Nonpoint source pollution
Encyclopedia
Water pollution
Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
affects a water body from sources such as polluted runoff
Surface runoff
Surface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...
from agricultural areas draining into a river, or wind-borne debris blowing out to sea. Nonpoint source air pollution affects air quality from sources such as smokestacks or car tailpipes. Although these pollutants have originated from a point source, the long-range transport ability and multiple sources of the pollutant make it a nonpoint source of pollution. Nonpoint source pollution can be contrasted with point source
Point source (pollution)
A point source of pollution is a single identifiable localized source of air, water, thermal, noise or light pollution. A point source has negligible extent, distinguishing it from other pollution source geometries. The sources are called point sources because in mathematical modeling, they can be...
pollution, where discharges occur to a body of water or into the atmosphere at a single location.
NPS may derive from many different sources with no specific solution to rectify the problem, making it difficult to regulate. It is the leading cause of water pollution in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
today, with polluted runoff from agriculture the primary cause.
Other significant sources of runoff include hydrological and habitat modification
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
, and silviculture
Silviculture
Silviculture is the practice of controlling the establishment, growth, composition, health, and quality of forests to meet diverse needs and values. The name comes from the Latin silvi- + culture...
(forestry).
Contaminated stormwater washed off of parking lot
Parking lot
A parking lot , also known as car lot, is a cleared area that is intended for parking vehicles. Usually, the term refers to a dedicated area that has been provided with a durable or semi-durable surface....
s, road
Road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...
s and highway
Highway
A highway is any public road. In American English, the term is common and almost always designates major roads. In British English, the term designates any road open to the public. Any interconnected set of highways can be variously referred to as a "highway system", a "highway network", or a...
s, and lawn
Lawn
A lawn is an area of aesthetic and recreational land planted with grasses or other durable plants, which usually are maintained at a low and consistent height. Low ornamental meadows in natural landscaping styles are a contemporary option of a lawn...
s (often containing fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
s and pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
s) is called urban runoff
Urban runoff
Urban runoff is surface runoff of rainwater created by urbanization. This runoff is a major source of water pollution in many parts of the United States and other urban communities worldwide.-Overview:...
. This runoff is often classified as a type of NPS pollution. Some people may also consider it a point source because many times it is channeled into municipal storm drain systems and discharged through pipes to nearby surface water
Surface water
Surface water is water collecting on the ground or in a stream, river, lake, wetland, or ocean; it is related to water collecting as groundwater or atmospheric water....
s. However, not all urban runoff flows through storm drain systems before entering waterbodies. Some may flow directly into waterbodies, especially in developing and suburban areas. Also, unlike other types of point sources, such as industrial discharge, wastewater plants and other operations, pollution in urban runoff cannot be attributed to one activity or even group of activities. Therefore, because it is not caused by an easily identified and regulated activity, urban runoff pollution sources are also often treated as true nonpoint sources as municipalities work to abate them.
Principal types
Sediment
SedimentSediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
(loose soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
) includes silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
(fine particles) and suspended solids
Suspended solids
Suspended solids refers to small solid particles which remain in suspension in water as a colloid or due to the motion of the water. It is used as one indicator of water quality....
(larger particles). Sediment may enter surface waters from eroding stream banks, and from surface runoff
Surface runoff
Surface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...
due to improper plant cover on urban and rural land Sediment creates turbidity
Turbidity
Turbidity is the cloudiness or haziness of a fluid caused by individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality....
(cloudiness) in water bodies, reducing the amount of light reaching lower depths, which can inhibit growth of submerged aquatic plants and consequently affect species which are dependent on them, such as fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
and shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
. High turbidity levels also inhibit drinking water purification
Water purification
Water purification is the process of removing undesirable chemicals, materials, and biological contaminants from contaminated water. The goal is to produce water fit for a specific purpose...
systems.
Sediment can also be discharged from multiple different sources. Sources include construction
Construction
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...
sites (although these are point sources, which can be managed with erosion control
Erosion control
Erosion control is the practice of preventing or controlling wind or water erosion in agriculture, land development and construction. Effective erosion controls are important techniques in preventing water pollution and soil loss.-Introduction:...
s and sediment control
Sediment control
A sediment control is a practice or device designed to keep eroded soil on a construction site, so that it does not wash off and cause water pollution to a nearby stream, river, lake, or bay...
s), agricultural fields, stream banks, and highly disturbed areas.
Nutrients
Nutrients mainly refers to organic matter from runoffs, landfill, livestock operation and corp lands, etc. It mainly include Phosphorus and Nitrogen.Phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
is a nutrient that occurs in many forms that are bioavailable. It is a main ingredient in many fertilizers used for agriculture as well as on residential and commercial properties, and may become a limiting nutrient in freshwater systems. Excess amounts of phosphorus in these systems lead to algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
blooms and consequently hypoxia
Hypoxia (environmental)
Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...
(in saltwater bodies) and eutrophication
Eutrophication
Eutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...
(in freshwater bodies). Phosphorus is most often transported to water bodies via soil erosion forms of phosphorus tend to be adsorbed
Adsorption
Adsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid...
to soil particles.
Nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
is the other key ingredient in fertilizers, and it becomes a pollutant in saltwater systems where nitrogen is a limiting nutrient. Excess amounts of bioavailable nitrogen in these systems lead to a bloom of algae and diatoms. When the excessively large population of autotrophs reach the end of their life cycles, the process of decomposition
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...
consumes oxygen. The result is very suppressed levels of dissolved oxygen in the water, otherwise known as hypoxia
Hypoxia (environmental)
Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...
.
Nitrogen is most often transported by water as nitrate
Nitrate
The nitrate ion is a polyatomic ion with the molecular formula NO and a molecular mass of 62.0049 g/mol. It is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by three identically-bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a...
(NO3). The nitrogen is usually added to a watershed as organic-N or ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
(NH3), so nitrogen stays attached to the soil until oxidation converts it into nitrate. Since the nitrate is generally already incorporated into the soil, the water traveling through the soil (i.e., interflow
Interflow
In hydrology, interflow is the lateral movement of water that occurs in the upper part of the unsaturated zone, or vadose zone, that directly enters a stream channel or other body of water without having occurred first as surface runoff ....
and tile drainage
Tile drainage
Tile drainage is an agriculture practice that removes excess water from soil subsurface. Whereas irrigation is the practice of adding additional water when the soil is naturally too dry, drainage brings soil moisture levels down for optimal crop growth...
) is the most likely to transport it, rather than surface runoff.
Toxic contaminants and chemicals
Compounds including heavy metals like leadLead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
, mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
, zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
, and cadmium
Cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Similar to zinc, it prefers oxidation state +2 in most of its compounds and similar to mercury it shows a low...
, organics like polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), fire retardants, and other substances are resistant to breakdown. These contaminants can come from a variety of sources including mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
operations, vehicle emissions, fossil fuel
Fossil fuel
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
combustion, urban runoff, industrial operations and landfills.
Toxic chemicals mainly include organic compounds
Organic
Organic may refer to:* Of or relating to an organism, a living entity* Of or relating to an organ- Chemistry :* Organic matter, matter that has come from a once-living organism, is capable of decay or the product of decay, or is composed of organic compound* Organic chemistry, chemistry involving...
and inorganic compounds. These compounds include pesticides like DDT
DDT
DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....
, acids, and salts that have severe effects to the ecosystem and waterbodies. These compounds can threaten the health of both humans and aquatic species while being resistant to environmental breakdown, thus allowing them to persist in the environment. These toxic chemicals could come from croplands, nurseries, orchards, building sites, gardens, lawns and landfills.
Acids and salts mainly are inorganic pollutants from irrigated lands, mining operations, urban runoffs, industrial sites and landfills.
Pathogens
Pathogens are bacteria and viruses that can be found in water and cause diseases in humans. Typically, pathogens cause disease when they are present in public drinking water supplies. Pathogens found in contaminated runoff may include:- Cryptosporidium parvumCryptosporidium parvumCryptosporidium parvum is one of several protozoal species that cause cryptosporidiosis, a parasitic disease of the mammalian intestinal tract....
- Giardia lambliaGiardia lambliaGiardia lamblia is a flagellated protozoan parasite that colonizes and reproduces in the small intestine, causing giardiasis. The giardia parasite attaches to the epithelium by a ventral adhesive disc, and reproduces via binary fission...
- SalmonellaSalmonellaSalmonella is a genus of rod-shaped, Gram-negative, non-spore-forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which grade in all directions . They are chemoorganotrophs, obtaining their energy from oxidation and reduction...
- Novovirus and other virusVirusA virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es - Parasitic wormParasitic wormParasitic worms or helminths are a division of eukaryoticparasites that, unlike external parasites such as lice and fleas, live inside their host. They are worm-like organisms that live and feed off living hosts, receiving nourishment and protection while disrupting their hosts' nutrient...
s (helminths).
Coliform bacteria
Coliform bacteria
Coliform bacteria are a commonly used bacterial indicator of sanitary quality of foods and water. They are defined as rod-shaped Gram-negative non-spore forming bacteria which can ferment lactose with the production of acid and gas when incubated at 35-37°C...
and fecal matter
Fecal Matter
Fecal Matter was a short-lived punk band from Aberdeen, Washington, that formed in late 1985. It was the first band conceived by Kurt Cobain, who would become famous as the frontman and guitarist of the seminal grunge band, Nirvana. The band recorded only one demo tape, Illiteracy Will Prevail,...
may also be detected in runoff. These bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
are a commonly used indicator
Indicator bacteria
Indicator bacteria are types of bacteria used to detect and estimate the level of fecal contamination of water.Each gram of human feces contains approximately ~100 billion bacteria . These bacteria may include species of pathogenic bacteria, such as Salmonella or Campylobacter, associated with...
of water pollution, but not an actual cause of disease.
Pathogens may contaminate runoff due to poorly managed livestock
Livestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...
operations, faulty septic systems, improper handling of pet waste, contaminated storm sewers, and sewer overflow.
Urban and suburban areas
UrbanUrban area
An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...
and Suburban Areas are a main sources of nonpoint source pollution due to the amount of runoff
Runoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
that is produced due to the large amount of paved surfaces. Paved surfaces, such as asphalt
Asphalt
Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...
and concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
are impervious to water penetrating them. Any water that is on contact with these surfaces will run off and be absorbed by the surrounding environment. These surfaces make it easier for stormwater to carry pollutants into the surrounding soil.
Construction sites located in urban
Urban area
An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...
and suburban areas tend to have disturbed soil that is easily eroded by precipitation
Precipitation
Precipitation may refer to:* Precipitation , rain, sleet, hail, snow and other forms of water falling from the sky* Precipitation , the condensation of a solid from a solution during a chemical reaction...
like rain
Rain
Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...
, snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
, and hail
Hail
Hail is a form of solid precipitation. It consists of balls or irregular lumps of ice, each of which is referred to as a hail stone. Hail stones on Earth consist mostly of water ice and measure between and in diameter, with the larger stones coming from severe thunderstorms...
. Additionally, discarded debris on the site can be carried away by runoff waters and enter the aquatic environment.
Typically, in suburban areas, chemicals are used for lawn care. These chemicals can end up in runoff and enter the surrounding environment via storm drain
Storm drain
A storm drain, storm sewer , stormwater drain or drainage well system or simply a drain or drain system is designed to drain excess rain and ground water from paved streets, parking lots, sidewalks, and roofs. Storm drains vary in design from small residential dry wells to large municipal systems...
s in the city. Since the water in storm drains is not treated before flowing into surrounding waterbodies, the chemicals enter the water directly.
Agricultural operations
AgriculturalAgriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
operations account for a large percentage of all nonpoint source pollution in the United States. When large tracts of land are plowed to grow crops, it exposes and loosens soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
that was once buried. This makes the exposed soil more vulnerable to erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
during rainstorms. It also can increase the amount of fertilizer and pesticides carried into nearby bodies of water.
Atmospheric inputs
Atmospheric inputs of pollutionPollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
into the air can come from multiple sources. Typically, industrial facilities, like factories
Factory
A factory or manufacturing plant is an industrial building where laborers manufacture goods or supervise machines processing one product into another. Most modern factories have large warehouses or warehouse-like facilities that contain heavy equipment used for assembly line production...
, discharge pollution via a smokestack. Although this is a point source of pollution, due to the distributional nature, long-rage transport, and multiple sources of the pollution, it is considered a nonpoint source. Additionally, atmospheric pollution can become water pollution
Water pollution
Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
by being washed out of the atmosphere in the form of rain
Rain
Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...
or snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
.
Forestry and mining operations
ForestryForestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
and mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
operations can have significant inputs to nonpoint source pollution.
Forestry
ForestryForestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
operations reduce the number of trees in a given area, thus reducing the soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
stability in that area as well. This action, coupled with the heavy machinery rolling over the soil increases the risk of erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
.
Mining
Active mining operations are considered point sources of pollution, however runoffRunoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
from abandoned mining operations contribute to nonpoint source pollution. In strip mining operations, the top of the mountain is removed to expose the desired ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
. If this area is not properly reclaimed once the mining has finished, soil erosion can occur. Additionally, there can be chemical reactions with the air and newly exposed rock to create acidic runoff
Runoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
. Water that seeps out of abandoned subsurface mines can also be highly acidic. This can seep into the nearest body of water and change the pH in the aquatic environment.
Marinas and boating activities
Chemicals used for boat maintenance, like paintPaint
Paint is any liquid, liquefiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film. One may also consider the digital mimicry thereof...
, solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
s, and oil
Oil
An oil is any substance that is liquid at ambient temperatures and does not mix with water but may mix with other oils and organic solvents. This general definition includes vegetable oils, volatile essential oils, petrochemical oils, and synthetic oils....
s find their way into water through runoff. Additionally, spilling fuels or leaking fuels directly into the water from boats contribute to nonpoint source pollution. Nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...
and bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
levels are increased by poorly maintained sanitary waste receptacles on the boat and pump-out stations.
Control
Urban and suburban areas
To control for nonpoint source pollution, many different approaches can be undertaken in both urban and suburban areas. Buffer stripBuffer strip
A buffer strip is an area of land maintained in permanent vegetation that helps to control air, soil, and water quality, along with other environmental problems, dealing primarily on land that is used in agriculture. Buffer strips trap sediment, and enhance filtration of nutrients and pesticides by...
s provide a barrier of grass in between impervious paving material like parking lots and roads, and the closest body of water. This allows the soil to absorb any pollution before it enters the local aquatic system. Retention ponds can be built in drainage areas to create an aquatic buffer between runoff
Runoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
pollution and the aquatic environment. Runoff
Runoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
and storm water drain into the retention pond allowing for the contaminates to settle out and become trapped in the pond. The use of porous pavement
Permeable paving
Permeable paving is a range of materials and techniques for paving roads, cycle-paths, parking lots and sidewalks that allow the movement of water and air around the paving material. Although some porous paving materials appear nearly indistinguishable from nonporous materials, their environmental...
allows for rain and storm water to drain into the ground beneath the pavement, reducing the amount of runoff that drain directly into the water body. Restoration methods such as constructing wetlands are also used to slow runoff as well as absorb contamination.
Construction site
Construction Site
Construction Site is a television series created by The Jim Henson Company in 1999, and consists of 7 construction vehicles. The show was broadcast on ABC Kids for a while, and had a range of videos. It was originally produced for and shown on CITV starting in 1999. In 2000 it was nominated for a...
s typically implement simple measures to reduce pollution and runoff. Firstly, sediment or silt fence
Silt fence
A silt fence, sometimes called a "filter fence," is a temporary sediment control device used on construction sites to protect water quality in nearby streams, rivers, lakes and bays from sediment in stormwater runoff...
s are erected around construction sites to reduce the amount of sediment and large material draining into the nearby water body. Secondly, laying grass or straw along the border of construction sites also work to reduce nonpoint source pollution.
Agricultural operations
To control sediment and runoff, farmers may utilize erosion controlErosion control
Erosion control is the practice of preventing or controlling wind or water erosion in agriculture, land development and construction. Effective erosion controls are important techniques in preventing water pollution and soil loss.-Introduction:...
s to reduce runoff flows and retain soil on their fields. Common techniques include contour plowing
Contour plowing
Contour plowing or contour farming is the farming practice of plowing across a slope following its elevation contour lines. The rows formed slow water run-off during rainstorms to prevent soil erosion and allow the water time to settle into the soil...
, crop mulch
Mulch
In agriculture and gardening, is a protective cover placed over the soil to retain moisture, reduce erosion, provide nutrients, and suppress weed growth and seed germination. Mulching in gardens and landscaping mimics the leaf cover that is found on forest floors....
ing, crop rotation
Crop rotation
Crop rotation is the practice of growing a series of dissimilar types of crops in the same area in sequential seasons.Crop rotation confers various benefits to the soil. A traditional element of crop rotation is the replenishment of nitrogen through the use of green manure in sequence with cereals...
, planting perennial crops and installing riparian buffer
Riparian buffer
A riparian buffer is a vegetated area near a stream, usually forested, which helps shade and partially protect a stream from the impact of adjacent land uses...
s. Conservation tillage is a concept used to reduce runoff while planting a new crop. The farmer leaves some crop reside from the previous planting in the ground to help prevent runoff during the planting process.
Nutrients (nitrogen and phosphorus) are typically applied to farmland as commercial fertilizer; animal manure
Manure
Manure is organic matter used as organic fertilizer in agriculture. Manures contribute to the fertility of the soil by adding organic matter and nutrients, such as nitrogen, that are trapped by bacteria in the soil...
; or spraying of municipal or industrial wastewater (effluent) or sludge. Nutrients may also enter runoff from crop residue
Crop residue
There are two types of agricultural crop residues:Field residues are materials left in an agricultural field or orchard after the crop has been harvested. These residues include stalks and stubble , leaves, and seed pods...
s, irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...
water, wildlife
Wildlife
Wildlife includes all non-domesticated plants, animals and other organisms. Domesticating wild plant and animal species for human benefit has occurred many times all over the planet, and has a major impact on the environment, both positive and negative....
, and atmospheric deposition
Deposition (Aerosol physics)
In aerosol physics, Deposition is the process by which aerosol particles collect or deposit themselves on solid surfaces, decreasing the concentration of the particles in the air. It can be divided into two sub-processes: dry and wet deposition. The rate of deposition, or the deposition velocity,...
. Farmers can develop and implement nutrient management
Nutrient management
Nutrient management is a system used by farmers to manage the amount, form, placement, and timing of the application of nutrients to plants...
plans to reduce excess application of nutrients.
To minimize pesticide impacts, farmers may use Integrated Pest Management
Integrated Pest Management
Integrated pest management is an ecological approach to agricultural pest control that integrates pesticides/herbicides into a management system incorporating a range of practices for economic control of a pest...
(IPM) techniques (which can include biological pest control
Biological pest control
Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...
) to maintain control over pests, reduce reliance on chemical pesticides, and protect water quality.
Forestry operations
With well planned placement of both logging trails, also called skid trails, can reduce the amount of sedimentSediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
generated. By planning the trails location as far away from the logging activity as possible as well as contouring the trails with the land, it can reduce the amount of loose sediment in the runoff. Additionally, by replanting trees on the land after logging, it provides a structure for the soil to regain stability as well as replaces the logged environment.
Marinas
By installing shut off valves on fuel pumps at the dock, it can help reduce the amount of spillover into the water. Additionally, pump-out stations that are easily accessible to boaters in the marina can provide a clean place in which to dispose of sanitary waste without dumping it directly into the water. Finally, something as simple as having trash containers around the marina can prevent large objects from entering the water.Water pollution
Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
affects a water body from sources such as polluted runoff
Surface runoff
Surface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...
from agricultural areas draining into a river, or wind-borne debris blowing out to sea. Nonpoint source air pollution affects air quality from sources such as smokestacks or car tailpipes. Although these pollutants have originated from a point source, the long-range transport ability and multiple sources of the pollutant make it a nonpoint source of pollution. Nonpoint source pollution can be contrasted with point source
Point source (pollution)
A point source of pollution is a single identifiable localized source of air, water, thermal, noise or light pollution. A point source has negligible extent, distinguishing it from other pollution source geometries. The sources are called point sources because in mathematical modeling, they can be...
pollution, where discharges occur to a body of water or into the atmosphere at a single location.
NPS may derive from many different sources with no specific solution to rectify the problem, making it difficult to regulate. It is the leading cause of water pollution in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
today, with polluted runoff from agriculture the primary cause.
Other significant sources of runoff include hydrological and habitat modification
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
, and silviculture
Silviculture
Silviculture is the practice of controlling the establishment, growth, composition, health, and quality of forests to meet diverse needs and values. The name comes from the Latin silvi- + culture...
(forestry).
Contaminated stormwater washed off of parking lot
Parking lot
A parking lot , also known as car lot, is a cleared area that is intended for parking vehicles. Usually, the term refers to a dedicated area that has been provided with a durable or semi-durable surface....
s, road
Road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...
s and highway
Highway
A highway is any public road. In American English, the term is common and almost always designates major roads. In British English, the term designates any road open to the public. Any interconnected set of highways can be variously referred to as a "highway system", a "highway network", or a...
s, and lawn
Lawn
A lawn is an area of aesthetic and recreational land planted with grasses or other durable plants, which usually are maintained at a low and consistent height. Low ornamental meadows in natural landscaping styles are a contemporary option of a lawn...
s (often containing fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
s and pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
s) is called urban runoff
Urban runoff
Urban runoff is surface runoff of rainwater created by urbanization. This runoff is a major source of water pollution in many parts of the United States and other urban communities worldwide.-Overview:...
. This runoff is often classified as a type of NPS pollution. Some people may also consider it a point source because many times it is channeled into municipal storm drain systems and discharged through pipes to nearby surface water
Surface water
Surface water is water collecting on the ground or in a stream, river, lake, wetland, or ocean; it is related to water collecting as groundwater or atmospheric water....
s. However, not all urban runoff flows through storm drain systems before entering waterbodies. Some may flow directly into waterbodies, especially in developing and suburban areas. Also, unlike other types of point sources, such as industrial discharge, wastewater plants and other operations, pollution in urban runoff cannot be attributed to one activity or even group of activities. Therefore, because it is not caused by an easily identified and regulated activity, urban runoff pollution sources are also often treated as true nonpoint sources as municipalities work to abate them.
Principal types
Sediment
SedimentSediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
(loose soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
) includes silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
(fine particles) and suspended solids
Suspended solids
Suspended solids refers to small solid particles which remain in suspension in water as a colloid or due to the motion of the water. It is used as one indicator of water quality....
(larger particles). Sediment may enter surface waters from eroding stream banks, and from surface runoff
Surface runoff
Surface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...
due to improper plant cover on urban and rural land Sediment creates turbidity
Turbidity
Turbidity is the cloudiness or haziness of a fluid caused by individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality....
(cloudiness) in water bodies, reducing the amount of light reaching lower depths, which can inhibit growth of submerged aquatic plants and consequently affect species which are dependent on them, such as fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
and shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
. High turbidity levels also inhibit drinking water purification
Water purification
Water purification is the process of removing undesirable chemicals, materials, and biological contaminants from contaminated water. The goal is to produce water fit for a specific purpose...
systems.
Sediment can also be discharged from multiple different sources. Sources include construction
Construction
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...
sites (although these are point sources, which can be managed with erosion control
Erosion control
Erosion control is the practice of preventing or controlling wind or water erosion in agriculture, land development and construction. Effective erosion controls are important techniques in preventing water pollution and soil loss.-Introduction:...
s and sediment control
Sediment control
A sediment control is a practice or device designed to keep eroded soil on a construction site, so that it does not wash off and cause water pollution to a nearby stream, river, lake, or bay...
s), agricultural fields, stream banks, and highly disturbed areas.
Nutrients
Nutrients mainly refers to organic matter from runoffs, landfill, livestock operation and corp lands, etc. It mainly include Phosphorus and Nitrogen.Phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
is a nutrient that occurs in many forms that are bioavailable. It is a main ingredient in many fertilizers used for agriculture as well as on residential and commercial properties, and may become a limiting nutrient in freshwater systems. Excess amounts of phosphorus in these systems lead to algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
blooms and consequently hypoxia
Hypoxia (environmental)
Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...
(in saltwater bodies) and eutrophication
Eutrophication
Eutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...
(in freshwater bodies). Phosphorus is most often transported to water bodies via soil erosion forms of phosphorus tend to be adsorbed
Adsorption
Adsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid...
to soil particles.
Nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
is the other key ingredient in fertilizers, and it becomes a pollutant in saltwater systems where nitrogen is a limiting nutrient. Excess amounts of bioavailable nitrogen in these systems lead to a bloom of algae and diatoms. When the excessively large population of autotrophs reach the end of their life cycles, the process of decomposition
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...
consumes oxygen. The result is very suppressed levels of dissolved oxygen in the water, otherwise known as hypoxia
Hypoxia (environmental)
Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...
.
Nitrogen is most often transported by water as nitrate
Nitrate
The nitrate ion is a polyatomic ion with the molecular formula NO and a molecular mass of 62.0049 g/mol. It is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by three identically-bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a...
(NO3). The nitrogen is usually added to a watershed as organic-N or ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
(NH3), so nitrogen stays attached to the soil until oxidation converts it into nitrate. Since the nitrate is generally already incorporated into the soil, the water traveling through the soil (i.e., interflow
Interflow
In hydrology, interflow is the lateral movement of water that occurs in the upper part of the unsaturated zone, or vadose zone, that directly enters a stream channel or other body of water without having occurred first as surface runoff ....
and tile drainage
Tile drainage
Tile drainage is an agriculture practice that removes excess water from soil subsurface. Whereas irrigation is the practice of adding additional water when the soil is naturally too dry, drainage brings soil moisture levels down for optimal crop growth...
) is the most likely to transport it, rather than surface runoff.
Toxic contaminants and chemicals
Compounds including heavy metals like leadLead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
, mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
, zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
, and cadmium
Cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Similar to zinc, it prefers oxidation state +2 in most of its compounds and similar to mercury it shows a low...
, organics like polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), fire retardants, and other substances are resistant to breakdown. These contaminants can come from a variety of sources including mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
operations, vehicle emissions, fossil fuel
Fossil fuel
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
combustion, urban runoff, industrial operations and landfills.
Toxic chemicals mainly include organic compounds
Organic
Organic may refer to:* Of or relating to an organism, a living entity* Of or relating to an organ- Chemistry :* Organic matter, matter that has come from a once-living organism, is capable of decay or the product of decay, or is composed of organic compound* Organic chemistry, chemistry involving...
and inorganic compounds. These compounds include pesticides like DDT
DDT
DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....
, acids, and salts that have severe effects to the ecosystem and waterbodies. These compounds can threaten the health of both humans and aquatic species while being resistant to environmental breakdown, thus allowing them to persist in the environment. These toxic chemicals could come from croplands, nurseries, orchards, building sites, gardens, lawns and landfills.
Acids and salts mainly are inorganic pollutants from irrigated lands, mining operations, urban runoffs, industrial sites and landfills.
Pathogens
Pathogens are bacteria and viruses that can be found in water and cause diseases in humans. Typically, pathogens cause disease when they are present in public drinking water supplies. Pathogens found in contaminated runoff may include:- Cryptosporidium parvumCryptosporidium parvumCryptosporidium parvum is one of several protozoal species that cause cryptosporidiosis, a parasitic disease of the mammalian intestinal tract....
- Giardia lambliaGiardia lambliaGiardia lamblia is a flagellated protozoan parasite that colonizes and reproduces in the small intestine, causing giardiasis. The giardia parasite attaches to the epithelium by a ventral adhesive disc, and reproduces via binary fission...
- SalmonellaSalmonellaSalmonella is a genus of rod-shaped, Gram-negative, non-spore-forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which grade in all directions . They are chemoorganotrophs, obtaining their energy from oxidation and reduction...
- Novovirus and other virusVirusA virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es - Parasitic wormParasitic wormParasitic worms or helminths are a division of eukaryoticparasites that, unlike external parasites such as lice and fleas, live inside their host. They are worm-like organisms that live and feed off living hosts, receiving nourishment and protection while disrupting their hosts' nutrient...
s (helminths).
Coliform bacteria
Coliform bacteria
Coliform bacteria are a commonly used bacterial indicator of sanitary quality of foods and water. They are defined as rod-shaped Gram-negative non-spore forming bacteria which can ferment lactose with the production of acid and gas when incubated at 35-37°C...
and fecal matter
Fecal Matter
Fecal Matter was a short-lived punk band from Aberdeen, Washington, that formed in late 1985. It was the first band conceived by Kurt Cobain, who would become famous as the frontman and guitarist of the seminal grunge band, Nirvana. The band recorded only one demo tape, Illiteracy Will Prevail,...
may also be detected in runoff. These bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
are a commonly used indicator
Indicator bacteria
Indicator bacteria are types of bacteria used to detect and estimate the level of fecal contamination of water.Each gram of human feces contains approximately ~100 billion bacteria . These bacteria may include species of pathogenic bacteria, such as Salmonella or Campylobacter, associated with...
of water pollution, but not an actual cause of disease.
Pathogens may contaminate runoff due to poorly managed livestock
Livestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...
operations, faulty septic systems, improper handling of pet waste, contaminated storm sewers, and sewer overflow.
Urban and suburban areas
UrbanUrban area
An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...
and Suburban Areas are a main sources of nonpoint source pollution due to the amount of runoff
Runoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
that is produced due to the large amount of paved surfaces. Paved surfaces, such as asphalt
Asphalt
Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...
and concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
are impervious to water penetrating them. Any water that is on contact with these surfaces will run off and be absorbed by the surrounding environment. These surfaces make it easier for stormwater to carry pollutants into the surrounding soil.
Construction sites located in urban
Urban area
An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...
and suburban areas tend to have disturbed soil that is easily eroded by precipitation
Precipitation
Precipitation may refer to:* Precipitation , rain, sleet, hail, snow and other forms of water falling from the sky* Precipitation , the condensation of a solid from a solution during a chemical reaction...
like rain
Rain
Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...
, snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
, and hail
Hail
Hail is a form of solid precipitation. It consists of balls or irregular lumps of ice, each of which is referred to as a hail stone. Hail stones on Earth consist mostly of water ice and measure between and in diameter, with the larger stones coming from severe thunderstorms...
. Additionally, discarded debris on the site can be carried away by runoff waters and enter the aquatic environment.
Typically, in suburban areas, chemicals are used for lawn care. These chemicals can end up in runoff and enter the surrounding environment via storm drain
Storm drain
A storm drain, storm sewer , stormwater drain or drainage well system or simply a drain or drain system is designed to drain excess rain and ground water from paved streets, parking lots, sidewalks, and roofs. Storm drains vary in design from small residential dry wells to large municipal systems...
s in the city. Since the water in storm drains is not treated before flowing into surrounding waterbodies, the chemicals enter the water directly.
Agricultural operations
AgriculturalAgriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
operations account for a large percentage of all nonpoint source pollution in the United States. When large tracts of land are plowed to grow crops, it exposes and loosens soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
that was once buried. This makes the exposed soil more vulnerable to erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
during rainstorms. It also can increase the amount of fertilizer and pesticides carried into nearby bodies of water.
Atmospheric inputs
Atmospheric inputs of pollutionPollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
into the air can come from multiple sources. Typically, industrial facilities, like factories
Factory
A factory or manufacturing plant is an industrial building where laborers manufacture goods or supervise machines processing one product into another. Most modern factories have large warehouses or warehouse-like facilities that contain heavy equipment used for assembly line production...
, discharge pollution via a smokestack. Although this is a point source of pollution, due to the distributional nature, long-rage transport, and multiple sources of the pollution, it is considered a nonpoint source. Additionally, atmospheric pollution can become water pollution
Water pollution
Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
by being washed out of the atmosphere in the form of rain
Rain
Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...
or snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
.
Forestry and mining operations
ForestryForestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
and mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
operations can have significant inputs to nonpoint source pollution.
Forestry
ForestryForestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
operations reduce the number of trees in a given area, thus reducing the soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
stability in that area as well. This action, coupled with the heavy machinery rolling over the soil increases the risk of erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
.
Mining
Active mining operations are considered point sources of pollution, however runoffRunoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
from abandoned mining operations contribute to nonpoint source pollution. In strip mining operations, the top of the mountain is removed to expose the desired ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
. If this area is not properly reclaimed once the mining has finished, soil erosion can occur. Additionally, there can be chemical reactions with the air and newly exposed rock to create acidic runoff
Runoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
. Water that seeps out of abandoned subsurface mines can also be highly acidic. This can seep into the nearest body of water and change the pH in the aquatic environment.
Marinas and boating activities
Chemicals used for boat maintenance, like paintPaint
Paint is any liquid, liquefiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film. One may also consider the digital mimicry thereof...
, solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
s, and oil
Oil
An oil is any substance that is liquid at ambient temperatures and does not mix with water but may mix with other oils and organic solvents. This general definition includes vegetable oils, volatile essential oils, petrochemical oils, and synthetic oils....
s find their way into water through runoff. Additionally, spilling fuels or leaking fuels directly into the water from boats contribute to nonpoint source pollution. Nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...
and bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
levels are increased by poorly maintained sanitary waste receptacles on the boat and pump-out stations.
Control
Urban and suburban areas
To control for nonpoint source pollution, many different approaches can be undertaken in both urban and suburban areas. Buffer stripBuffer strip
A buffer strip is an area of land maintained in permanent vegetation that helps to control air, soil, and water quality, along with other environmental problems, dealing primarily on land that is used in agriculture. Buffer strips trap sediment, and enhance filtration of nutrients and pesticides by...
s provide a barrier of grass in between impervious paving material like parking lots and roads, and the closest body of water. This allows the soil to absorb any pollution before it enters the local aquatic system. Retention ponds can be built in drainage areas to create an aquatic buffer between runoff
Runoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
pollution and the aquatic environment. Runoff
Runoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
and storm water drain into the retention pond allowing for the contaminates to settle out and become trapped in the pond. The use of porous pavement
Permeable paving
Permeable paving is a range of materials and techniques for paving roads, cycle-paths, parking lots and sidewalks that allow the movement of water and air around the paving material. Although some porous paving materials appear nearly indistinguishable from nonporous materials, their environmental...
allows for rain and storm water to drain into the ground beneath the pavement, reducing the amount of runoff that drain directly into the water body. Restoration methods such as constructing wetlands are also used to slow runoff as well as absorb contamination.
Construction site
Construction Site
Construction Site is a television series created by The Jim Henson Company in 1999, and consists of 7 construction vehicles. The show was broadcast on ABC Kids for a while, and had a range of videos. It was originally produced for and shown on CITV starting in 1999. In 2000 it was nominated for a...
s typically implement simple measures to reduce pollution and runoff. Firstly, sediment or silt fence
Silt fence
A silt fence, sometimes called a "filter fence," is a temporary sediment control device used on construction sites to protect water quality in nearby streams, rivers, lakes and bays from sediment in stormwater runoff...
s are erected around construction sites to reduce the amount of sediment and large material draining into the nearby water body. Secondly, laying grass or straw along the border of construction sites also work to reduce nonpoint source pollution.
Agricultural operations
To control sediment and runoff, farmers may utilize erosion controlErosion control
Erosion control is the practice of preventing or controlling wind or water erosion in agriculture, land development and construction. Effective erosion controls are important techniques in preventing water pollution and soil loss.-Introduction:...
s to reduce runoff flows and retain soil on their fields. Common techniques include contour plowing
Contour plowing
Contour plowing or contour farming is the farming practice of plowing across a slope following its elevation contour lines. The rows formed slow water run-off during rainstorms to prevent soil erosion and allow the water time to settle into the soil...
, crop mulch
Mulch
In agriculture and gardening, is a protective cover placed over the soil to retain moisture, reduce erosion, provide nutrients, and suppress weed growth and seed germination. Mulching in gardens and landscaping mimics the leaf cover that is found on forest floors....
ing, crop rotation
Crop rotation
Crop rotation is the practice of growing a series of dissimilar types of crops in the same area in sequential seasons.Crop rotation confers various benefits to the soil. A traditional element of crop rotation is the replenishment of nitrogen through the use of green manure in sequence with cereals...
, planting perennial crops and installing riparian buffer
Riparian buffer
A riparian buffer is a vegetated area near a stream, usually forested, which helps shade and partially protect a stream from the impact of adjacent land uses...
s. Conservation tillage is a concept used to reduce runoff while planting a new crop. The farmer leaves some crop reside from the previous planting in the ground to help prevent runoff during the planting process.
Nutrients (nitrogen and phosphorus) are typically applied to farmland as commercial fertilizer; animal manure
Manure
Manure is organic matter used as organic fertilizer in agriculture. Manures contribute to the fertility of the soil by adding organic matter and nutrients, such as nitrogen, that are trapped by bacteria in the soil...
; or spraying of municipal or industrial wastewater (effluent) or sludge. Nutrients may also enter runoff from crop residue
Crop residue
There are two types of agricultural crop residues:Field residues are materials left in an agricultural field or orchard after the crop has been harvested. These residues include stalks and stubble , leaves, and seed pods...
s, irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...
water, wildlife
Wildlife
Wildlife includes all non-domesticated plants, animals and other organisms. Domesticating wild plant and animal species for human benefit has occurred many times all over the planet, and has a major impact on the environment, both positive and negative....
, and atmospheric deposition
Deposition (Aerosol physics)
In aerosol physics, Deposition is the process by which aerosol particles collect or deposit themselves on solid surfaces, decreasing the concentration of the particles in the air. It can be divided into two sub-processes: dry and wet deposition. The rate of deposition, or the deposition velocity,...
. Farmers can develop and implement nutrient management
Nutrient management
Nutrient management is a system used by farmers to manage the amount, form, placement, and timing of the application of nutrients to plants...
plans to reduce excess application of nutrients.
To minimize pesticide impacts, farmers may use Integrated Pest Management
Integrated Pest Management
Integrated pest management is an ecological approach to agricultural pest control that integrates pesticides/herbicides into a management system incorporating a range of practices for economic control of a pest...
(IPM) techniques (which can include biological pest control
Biological pest control
Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...
) to maintain control over pests, reduce reliance on chemical pesticides, and protect water quality.
Forestry operations
With well planned placement of both logging trails, also called skid trails, can reduce the amount of sedimentSediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
generated. By planning the trails location as far away from the logging activity as possible as well as contouring the trails with the land, it can reduce the amount of loose sediment in the runoff. Additionally, by replanting trees on the land after logging, it provides a structure for the soil to regain stability as well as replaces the logged environment.
Marinas
By installing shut off valves on fuel pumps at the dock, it can help reduce the amount of spillover into the water. Additionally, pump-out stations that are easily accessible to boaters in the marina can provide a clean place in which to dispose of sanitary waste without dumping it directly into the water. Finally, something as simple as having trash containers around the marina can prevent large objects from entering the water.Water pollution
Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
affects a water body from sources such as polluted runoff
Surface runoff
Surface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...
from agricultural areas draining into a river, or wind-borne debris blowing out to sea. Nonpoint source air pollution affects air quality from sources such as smokestacks or car tailpipes. Although these pollutants have originated from a point source, the long-range transport ability and multiple sources of the pollutant make it a nonpoint source of pollution. Nonpoint source pollution can be contrasted with point source
Point source (pollution)
A point source of pollution is a single identifiable localized source of air, water, thermal, noise or light pollution. A point source has negligible extent, distinguishing it from other pollution source geometries. The sources are called point sources because in mathematical modeling, they can be...
pollution, where discharges occur to a body of water or into the atmosphere at a single location.
NPS may derive from many different sources with no specific solution to rectify the problem, making it difficult to regulate. It is the leading cause of water pollution in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
today, with polluted runoff from agriculture the primary cause.
Other significant sources of runoff include hydrological and habitat modification
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
, and silviculture
Silviculture
Silviculture is the practice of controlling the establishment, growth, composition, health, and quality of forests to meet diverse needs and values. The name comes from the Latin silvi- + culture...
(forestry).
Contaminated stormwater washed off of parking lot
Parking lot
A parking lot , also known as car lot, is a cleared area that is intended for parking vehicles. Usually, the term refers to a dedicated area that has been provided with a durable or semi-durable surface....
s, road
Road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...
s and highway
Highway
A highway is any public road. In American English, the term is common and almost always designates major roads. In British English, the term designates any road open to the public. Any interconnected set of highways can be variously referred to as a "highway system", a "highway network", or a...
s, and lawn
Lawn
A lawn is an area of aesthetic and recreational land planted with grasses or other durable plants, which usually are maintained at a low and consistent height. Low ornamental meadows in natural landscaping styles are a contemporary option of a lawn...
s (often containing fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
s and pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
s) is called urban runoff
Urban runoff
Urban runoff is surface runoff of rainwater created by urbanization. This runoff is a major source of water pollution in many parts of the United States and other urban communities worldwide.-Overview:...
. This runoff is often classified as a type of NPS pollution. Some people may also consider it a point source because many times it is channeled into municipal storm drain systems and discharged through pipes to nearby surface water
Surface water
Surface water is water collecting on the ground or in a stream, river, lake, wetland, or ocean; it is related to water collecting as groundwater or atmospheric water....
s. However, not all urban runoff flows through storm drain systems before entering waterbodies. Some may flow directly into waterbodies, especially in developing and suburban areas. Also, unlike other types of point sources, such as industrial discharge, wastewater plants and other operations, pollution in urban runoff cannot be attributed to one activity or even group of activities. Therefore, because it is not caused by an easily identified and regulated activity, urban runoff pollution sources are also often treated as true nonpoint sources as municipalities work to abate them.
Principal types
Sediment
SedimentSediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
(loose soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
) includes silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
(fine particles) and suspended solids
Suspended solids
Suspended solids refers to small solid particles which remain in suspension in water as a colloid or due to the motion of the water. It is used as one indicator of water quality....
(larger particles). Sediment may enter surface waters from eroding stream banks, and from surface runoff
Surface runoff
Surface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...
due to improper plant cover on urban and rural land Sediment creates turbidity
Turbidity
Turbidity is the cloudiness or haziness of a fluid caused by individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality....
(cloudiness) in water bodies, reducing the amount of light reaching lower depths, which can inhibit growth of submerged aquatic plants and consequently affect species which are dependent on them, such as fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
and shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
. High turbidity levels also inhibit drinking water purification
Water purification
Water purification is the process of removing undesirable chemicals, materials, and biological contaminants from contaminated water. The goal is to produce water fit for a specific purpose...
systems.
Sediment can also be discharged from multiple different sources. Sources include construction
Construction
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...
sites (although these are point sources, which can be managed with erosion control
Erosion control
Erosion control is the practice of preventing or controlling wind or water erosion in agriculture, land development and construction. Effective erosion controls are important techniques in preventing water pollution and soil loss.-Introduction:...
s and sediment control
Sediment control
A sediment control is a practice or device designed to keep eroded soil on a construction site, so that it does not wash off and cause water pollution to a nearby stream, river, lake, or bay...
s), agricultural fields, stream banks, and highly disturbed areas.
Nutrients
Nutrients mainly refers to organic matter from runoffs, landfill, livestock operation and corp lands, etc. It mainly include Phosphorus and Nitrogen.Phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
is a nutrient that occurs in many forms that are bioavailable. It is a main ingredient in many fertilizers used for agriculture as well as on residential and commercial properties, and may become a limiting nutrient in freshwater systems. Excess amounts of phosphorus in these systems lead to algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
blooms and consequently hypoxia
Hypoxia (environmental)
Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...
(in saltwater bodies) and eutrophication
Eutrophication
Eutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...
(in freshwater bodies). Phosphorus is most often transported to water bodies via soil erosion forms of phosphorus tend to be adsorbed
Adsorption
Adsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid...
to soil particles.
Nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
is the other key ingredient in fertilizers, and it becomes a pollutant in saltwater systems where nitrogen is a limiting nutrient. Excess amounts of bioavailable nitrogen in these systems lead to a bloom of algae and diatoms. When the excessively large population of autotrophs reach the end of their life cycles, the process of decomposition
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...
consumes oxygen. The result is very suppressed levels of dissolved oxygen in the water, otherwise known as hypoxia
Hypoxia (environmental)
Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...
.
Nitrogen is most often transported by water as nitrate
Nitrate
The nitrate ion is a polyatomic ion with the molecular formula NO and a molecular mass of 62.0049 g/mol. It is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by three identically-bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a...
(NO3). The nitrogen is usually added to a watershed as organic-N or ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
(NH3), so nitrogen stays attached to the soil until oxidation converts it into nitrate. Since the nitrate is generally already incorporated into the soil, the water traveling through the soil (i.e., interflow
Interflow
In hydrology, interflow is the lateral movement of water that occurs in the upper part of the unsaturated zone, or vadose zone, that directly enters a stream channel or other body of water without having occurred first as surface runoff ....
and tile drainage
Tile drainage
Tile drainage is an agriculture practice that removes excess water from soil subsurface. Whereas irrigation is the practice of adding additional water when the soil is naturally too dry, drainage brings soil moisture levels down for optimal crop growth...
) is the most likely to transport it, rather than surface runoff.
Toxic contaminants and chemicals
Compounds including heavy metals like leadLead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
, mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
, zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
, and cadmium
Cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Similar to zinc, it prefers oxidation state +2 in most of its compounds and similar to mercury it shows a low...
, organics like polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), fire retardants, and other substances are resistant to breakdown. These contaminants can come from a variety of sources including mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
operations, vehicle emissions, fossil fuel
Fossil fuel
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
combustion, urban runoff, industrial operations and landfills.
Toxic chemicals mainly include organic compounds
Organic
Organic may refer to:* Of or relating to an organism, a living entity* Of or relating to an organ- Chemistry :* Organic matter, matter that has come from a once-living organism, is capable of decay or the product of decay, or is composed of organic compound* Organic chemistry, chemistry involving...
and inorganic compounds. These compounds include pesticides like DDT
DDT
DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....
, acids, and salts that have severe effects to the ecosystem and waterbodies. These compounds can threaten the health of both humans and aquatic species while being resistant to environmental breakdown, thus allowing them to persist in the environment. These toxic chemicals could come from croplands, nurseries, orchards, building sites, gardens, lawns and landfills.
Acids and salts mainly are inorganic pollutants from irrigated lands, mining operations, urban runoffs, industrial sites and landfills.
Pathogens
Pathogens are bacteria and viruses that can be found in water and cause diseases in humans. Typically, pathogens cause disease when they are present in public drinking water supplies. Pathogens found in contaminated runoff may include:- Cryptosporidium parvumCryptosporidium parvumCryptosporidium parvum is one of several protozoal species that cause cryptosporidiosis, a parasitic disease of the mammalian intestinal tract....
- Giardia lambliaGiardia lambliaGiardia lamblia is a flagellated protozoan parasite that colonizes and reproduces in the small intestine, causing giardiasis. The giardia parasite attaches to the epithelium by a ventral adhesive disc, and reproduces via binary fission...
- SalmonellaSalmonellaSalmonella is a genus of rod-shaped, Gram-negative, non-spore-forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which grade in all directions . They are chemoorganotrophs, obtaining their energy from oxidation and reduction...
- Novovirus and other virusVirusA virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es - Parasitic wormParasitic wormParasitic worms or helminths are a division of eukaryoticparasites that, unlike external parasites such as lice and fleas, live inside their host. They are worm-like organisms that live and feed off living hosts, receiving nourishment and protection while disrupting their hosts' nutrient...
s (helminths).
Coliform bacteria
Coliform bacteria
Coliform bacteria are a commonly used bacterial indicator of sanitary quality of foods and water. They are defined as rod-shaped Gram-negative non-spore forming bacteria which can ferment lactose with the production of acid and gas when incubated at 35-37°C...
and fecal matter
Fecal Matter
Fecal Matter was a short-lived punk band from Aberdeen, Washington, that formed in late 1985. It was the first band conceived by Kurt Cobain, who would become famous as the frontman and guitarist of the seminal grunge band, Nirvana. The band recorded only one demo tape, Illiteracy Will Prevail,...
may also be detected in runoff. These bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
are a commonly used indicator
Indicator bacteria
Indicator bacteria are types of bacteria used to detect and estimate the level of fecal contamination of water.Each gram of human feces contains approximately ~100 billion bacteria . These bacteria may include species of pathogenic bacteria, such as Salmonella or Campylobacter, associated with...
of water pollution, but not an actual cause of disease.
Pathogens may contaminate runoff due to poorly managed livestock
Livestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...
operations, faulty septic systems, improper handling of pet waste, contaminated storm sewers, and sewer overflow.
Urban and suburban areas
UrbanUrban area
An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...
and Suburban Areas are a main sources of nonpoint source pollution due to the amount of runoff
Runoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
that is produced due to the large amount of paved surfaces. Paved surfaces, such as asphalt
Asphalt
Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...
and concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
are impervious to water penetrating them. Any water that is on contact with these surfaces will run off and be absorbed by the surrounding environment. These surfaces make it easier for stormwater to carry pollutants into the surrounding soil.
Construction sites located in urban
Urban area
An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...
and suburban areas tend to have disturbed soil that is easily eroded by precipitation
Precipitation
Precipitation may refer to:* Precipitation , rain, sleet, hail, snow and other forms of water falling from the sky* Precipitation , the condensation of a solid from a solution during a chemical reaction...
like rain
Rain
Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...
, snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
, and hail
Hail
Hail is a form of solid precipitation. It consists of balls or irregular lumps of ice, each of which is referred to as a hail stone. Hail stones on Earth consist mostly of water ice and measure between and in diameter, with the larger stones coming from severe thunderstorms...
. Additionally, discarded debris on the site can be carried away by runoff waters and enter the aquatic environment.
Typically, in suburban areas, chemicals are used for lawn care. These chemicals can end up in runoff and enter the surrounding environment via storm drain
Storm drain
A storm drain, storm sewer , stormwater drain or drainage well system or simply a drain or drain system is designed to drain excess rain and ground water from paved streets, parking lots, sidewalks, and roofs. Storm drains vary in design from small residential dry wells to large municipal systems...
s in the city. Since the water in storm drains is not treated before flowing into surrounding waterbodies, the chemicals enter the water directly.
Agricultural operations
AgriculturalAgriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
operations account for a large percentage of all nonpoint source pollution in the United States. When large tracts of land are plowed to grow crops, it exposes and loosens soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
that was once buried. This makes the exposed soil more vulnerable to erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
during rainstorms. It also can increase the amount of fertilizer and pesticides carried into nearby bodies of water.
Atmospheric inputs
Atmospheric inputs of pollutionPollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
into the air can come from multiple sources. Typically, industrial facilities, like factories
Factory
A factory or manufacturing plant is an industrial building where laborers manufacture goods or supervise machines processing one product into another. Most modern factories have large warehouses or warehouse-like facilities that contain heavy equipment used for assembly line production...
, discharge pollution via a smokestack. Although this is a point source of pollution, due to the distributional nature, long-rage transport, and multiple sources of the pollution, it is considered a nonpoint source. Additionally, atmospheric pollution can become water pollution
Water pollution
Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
by being washed out of the atmosphere in the form of rain
Rain
Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...
or snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
.
Forestry and mining operations
ForestryForestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
and mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
operations can have significant inputs to nonpoint source pollution.
Forestry
ForestryForestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
operations reduce the number of trees in a given area, thus reducing the soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
stability in that area as well. This action, coupled with the heavy machinery rolling over the soil increases the risk of erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
.
Mining
Active mining operations are considered point sources of pollution, however runoffRunoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
from abandoned mining operations contribute to nonpoint source pollution. In strip mining operations, the top of the mountain is removed to expose the desired ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
. If this area is not properly reclaimed once the mining has finished, soil erosion can occur. Additionally, there can be chemical reactions with the air and newly exposed rock to create acidic runoff
Runoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
. Water that seeps out of abandoned subsurface mines can also be highly acidic. This can seep into the nearest body of water and change the pH in the aquatic environment.
Marinas and boating activities
Chemicals used for boat maintenance, like paintPaint
Paint is any liquid, liquefiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film. One may also consider the digital mimicry thereof...
, solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
s, and oil
Oil
An oil is any substance that is liquid at ambient temperatures and does not mix with water but may mix with other oils and organic solvents. This general definition includes vegetable oils, volatile essential oils, petrochemical oils, and synthetic oils....
s find their way into water through runoff. Additionally, spilling fuels or leaking fuels directly into the water from boats contribute to nonpoint source pollution. Nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...
and bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
levels are increased by poorly maintained sanitary waste receptacles on the boat and pump-out stations.
Control
Urban and suburban areas
To control for nonpoint source pollution, many different approaches can be undertaken in both urban and suburban areas. Buffer stripBuffer strip
A buffer strip is an area of land maintained in permanent vegetation that helps to control air, soil, and water quality, along with other environmental problems, dealing primarily on land that is used in agriculture. Buffer strips trap sediment, and enhance filtration of nutrients and pesticides by...
s provide a barrier of grass in between impervious paving material like parking lots and roads, and the closest body of water. This allows the soil to absorb any pollution before it enters the local aquatic system. Retention ponds can be built in drainage areas to create an aquatic buffer between runoff
Runoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
pollution and the aquatic environment. Runoff
Runoff
Run-off or runoff may refer to:* Surface runoff, the flow of water, from rain, snow melt, or other sources, over land* Runoff model , a mathematical model describing the rainfall-runoff relations of a rainfall catchment area or watershed...
and storm water drain into the retention pond allowing for the contaminates to settle out and become trapped in the pond. The use of porous pavement
Permeable paving
Permeable paving is a range of materials and techniques for paving roads, cycle-paths, parking lots and sidewalks that allow the movement of water and air around the paving material. Although some porous paving materials appear nearly indistinguishable from nonporous materials, their environmental...
allows for rain and storm water to drain into the ground beneath the pavement, reducing the amount of runoff that drain directly into the water body. Restoration methods such as constructing wetlands are also used to slow runoff as well as absorb contamination.
Construction site
Construction Site
Construction Site is a television series created by The Jim Henson Company in 1999, and consists of 7 construction vehicles. The show was broadcast on ABC Kids for a while, and had a range of videos. It was originally produced for and shown on CITV starting in 1999. In 2000 it was nominated for a...
s typically implement simple measures to reduce pollution and runoff. Firstly, sediment or silt fence
Silt fence
A silt fence, sometimes called a "filter fence," is a temporary sediment control device used on construction sites to protect water quality in nearby streams, rivers, lakes and bays from sediment in stormwater runoff...
s are erected around construction sites to reduce the amount of sediment and large material draining into the nearby water body. Secondly, laying grass or straw along the border of construction sites also work to reduce nonpoint source pollution.
Agricultural operations
To control sediment and runoff, farmers may utilize erosion controlErosion control
Erosion control is the practice of preventing or controlling wind or water erosion in agriculture, land development and construction. Effective erosion controls are important techniques in preventing water pollution and soil loss.-Introduction:...
s to reduce runoff flows and retain soil on their fields. Common techniques include contour plowing
Contour plowing
Contour plowing or contour farming is the farming practice of plowing across a slope following its elevation contour lines. The rows formed slow water run-off during rainstorms to prevent soil erosion and allow the water time to settle into the soil...
, crop mulch
Mulch
In agriculture and gardening, is a protective cover placed over the soil to retain moisture, reduce erosion, provide nutrients, and suppress weed growth and seed germination. Mulching in gardens and landscaping mimics the leaf cover that is found on forest floors....
ing, crop rotation
Crop rotation
Crop rotation is the practice of growing a series of dissimilar types of crops in the same area in sequential seasons.Crop rotation confers various benefits to the soil. A traditional element of crop rotation is the replenishment of nitrogen through the use of green manure in sequence with cereals...
, planting perennial crops and installing riparian buffer
Riparian buffer
A riparian buffer is a vegetated area near a stream, usually forested, which helps shade and partially protect a stream from the impact of adjacent land uses...
s. Conservation tillage is a concept used to reduce runoff while planting a new crop. The farmer leaves some crop reside from the previous planting in the ground to help prevent runoff during the planting process.
Nutrients (nitrogen and phosphorus) are typically applied to farmland as commercial fertilizer; animal manure
Manure
Manure is organic matter used as organic fertilizer in agriculture. Manures contribute to the fertility of the soil by adding organic matter and nutrients, such as nitrogen, that are trapped by bacteria in the soil...
; or spraying of municipal or industrial wastewater (effluent) or sludge. Nutrients may also enter runoff from crop residue
Crop residue
There are two types of agricultural crop residues:Field residues are materials left in an agricultural field or orchard after the crop has been harvested. These residues include stalks and stubble , leaves, and seed pods...
s, irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...
water, wildlife
Wildlife
Wildlife includes all non-domesticated plants, animals and other organisms. Domesticating wild plant and animal species for human benefit has occurred many times all over the planet, and has a major impact on the environment, both positive and negative....
, and atmospheric deposition
Deposition (Aerosol physics)
In aerosol physics, Deposition is the process by which aerosol particles collect or deposit themselves on solid surfaces, decreasing the concentration of the particles in the air. It can be divided into two sub-processes: dry and wet deposition. The rate of deposition, or the deposition velocity,...
. Farmers can develop and implement nutrient management
Nutrient management
Nutrient management is a system used by farmers to manage the amount, form, placement, and timing of the application of nutrients to plants...
plans to reduce excess application of nutrients.
To minimize pesticide impacts, farmers may use Integrated Pest Management
Integrated Pest Management
Integrated pest management is an ecological approach to agricultural pest control that integrates pesticides/herbicides into a management system incorporating a range of practices for economic control of a pest...
(IPM) techniques (which can include biological pest control
Biological pest control
Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...
) to maintain control over pests, reduce reliance on chemical pesticides, and protect water quality.
Forestry operations
With well planned placement of both logging trails, also called skid trails, can reduce the amount of sedimentSediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
generated. By planning the trails location as far away from the logging activity as possible as well as contouring the trails with the land, it can reduce the amount of loose sediment in the runoff. Additionally, by replanting trees on the land after logging, it provides a structure for the soil to regain stability as well as replaces the logged environment.
Marinas
By installing shut off valves on fuel pumps at the dock, it can help reduce the amount of spillover into the water. Additionally, pump-out stations that are easily accessible to boaters in the marina can provide a clean place in which to dispose of sanitary waste without dumping it directly into the water. Finally, something as simple as having trash containers around the marina can prevent large objects from entering the water.See also
- Nonpoint source pollution regulationNonpoint source water pollution regulations in the United StatesNonpoint source water pollution regulations are environmental regulations that restrict or limit water pollution from diffuse or nonpoint effluent sources such as polluted runoff from agricultural areas in a river catchments or wind-borne debris blowing out to sea. In the United States,...
- Agricultural surface runoff
- Agricultural nutrient runoff
- Agricultural wastewater
- Marine pollutionMarine pollutionMarine pollution occurs when harmful, or potentially harmful effects, can result from the entry into the ocean of chemicals, particles, industrial, agricultural and residential waste, noise, or the spread of invasive organisms. Most sources of marine pollution are land based...
- Point source pollution
- StormwaterStormwaterStormwater is water that originates during precipitation events. It may also be used to apply to water that originates with snowmelt that enters the stormwater system...
- Trophic state indexTrophic state indexThe quantities of nitrogen, phosphorus, and other biologically useful nutrients are theprimary determinants of a body of water's trophic state index...
- Urban runoffUrban runoffUrban runoff is surface runoff of rainwater created by urbanization. This runoff is a major source of water pollution in many parts of the United States and other urban communities worldwide.-Overview:...
- Water pollutionWater pollutionWater pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
- Water qualityWater qualityWater quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which...
External links
- U.S. EPA - Nonpoint Source Management Program
- Natural Resources Conservation ServiceNatural Resources Conservation ServiceThe Natural Resources Conservation Service , formerly known as the Soil Conservation Service , is an agency of the United States Department of Agriculture that provides technical assistance to farmers and other private landowners and managers.Its name was changed in 1994 during the Presidency of...
(U.S. Department of Agriculture):- Electronic Field Office Technical Guide - Detailed soil conservation guides tailored to individual states/counties
- Conservation Security Program - Financial & technical assistance to farmers
- "Practical ways to combat nonpoint source pollution" - Onondaga County Government, Syracuse, NY
