Kesterson Reservoir
Encyclopedia
The Kesterson Reservoir is the name of a former unit of the Kesterson National Wildlife Refuge which is part of the current San Luis National Wildlife Refuge
. The site gained national attention during the later half of the 20th century due to selenium
toxicity
and rapid die off of migratory waterfowl
, fish
, insects, plants and algae
within the Kesterson Reservoir.
in central California
. The reservoir and San Luis National Wildlife Refuge are located in western Merced County
, approximately 18 miles (29 km) north of Los Banos
, California. The refuge includes four units, the Kesterson, Freitas, Bear Creek and original San Luis Units. The refuge is 26609 acres (107.7 km²) and includes a variety of wetland
and riparian habitat which supports a large variety of waterfowl, mammals and other wildlife.
The San Joaquin Valley has been considered by historian Kevin Starr
as being "the most productive unnatural environment on Earth
" as approximately 25% of the United States
’ agricultural products originate from the valley. Examples of the agricultural exports from this area include grapes, cotton
, nuts
, citrus
, and vegetables. Cattle
and sheep ranching also contribute to the agricultural output of the area.
The San Joaquin Valley is bordered on the west by the Coast Range and on the east by the Sierra Nevada mountains. The Coast Range include Cretaceous
and Tertiary
marine sedimentary rocks. Weathering and oxidation of the Moreno Formation, a black marine shale, produces Pyrite
, FeS2, and Iron
Selenide
, FeSe2. As the weathered products concentrate in evaporative minerals and salts, selenates (for instance, Na2SeO4 · 10 H2O or Na2Mg(SeO4)2 · 4 H2O) and Sulfates (Na2SO4 · 10 H2O or Na2Mg(SO4)4 · 4 H2O) can form. This results in selenium salts and selenium rich soils that are sloughed off the mountains via debris flows or landslides into the San Joaquin valley. Additionally, the San Joaquin Valley has a shallow aquifer
bounded by impermeable clays.
The climate of the San Joaquin Valley does not lend itself well to agricultural production and results in large scale irrigation
projects in order to keep fertile farms in operation. According to some estimates, the climate of the San Joaquin Valley has approximately 10 inches (254 mm) of precipitation and over 90 inches (2,286 mm) of evaporation annually. In order to keep the area productive, irrigation is a requirement.
A side effect of irrigation in the San Joaquin Valley was that ground water levels began to rise over time. This led to a condition where excess water was accumulating and starting to harm crops. In 1968, the Bureau of Reclamation created the 134 km long San Luis Drain and the Kesterson Reservoir. Farmers in the San Joaquin valley installed drainage tiles in an effort to maintain water tables at 2 meters. The Kesterson reservoir was completed in 1971 by the Bureau of Reclamation and consisted of 12 evaporation ponds within the Kesterson National Wildlife Refuge.
drain water. Contributing to the salinity of the drain water was the highly-mobile ion of selenium, selenate
, SeO42-. Selenium begin to bioaccumulate in the waterfowl and wildlife that used the reservoir.
Prior to 1981, the Kesterson Reservoir supported a wide variety of life, including several species of fish. After 1981, the reservoir only supported the most saline tolerant mosquito fish. The habitat change occurred quickly and also included algal blooms and disappearing waterfowl. In 1982, the United States Fish and Wildlife Service
began a study to determine the cause for declining wildlife use at the reservoir. Selenium concentrations at these locations were found to be greater than 1400 micrograms per liter.
is an element that behaves very similarly to sulfur
. It is required for humans in small amounts, less than 55 micrograms. Selenium is the required element in the amino acids selenocysteine
and selenomethionine
. In humans, selenium is seen in antioxidant
enzymes such as gluthathione peroxidases and thioredoxin reductase
. It helps in the daily functioning of the thyroid gland. Selenium deficiency can lead to Keshan disease
, which is potentially fatal. Keshan disease includes such symptoms as myocardial necrosis which leads to weakening of the heart. If a diet is low in selenium and iodine
, Keshan-Beck disease may develop, which leads to immune deficiency, making the body less resilient to nutritional, biochemical and infectious diseases. Selenium is necessary for the conversion of the thyroid hormone thyroxine
(T4) into triiodothyronine
. A deficiency of selenium can cause hypothyroidism
, which results in extreme fatigue, mental slowing, Goitre
, cretinism
and miscarriage
.
In locations around the world with low selenium concentrations in soil, some research has indicated a higher incidence of HIV
/AIDS
. Lack of selenium strongly correlates with the progression of AIDS and the risk of death.
In concentrations greater than 400 micrograms per day, selenosis may develop. The symptoms of selenosis include gastrointestinal disorders, hair loss, sloughing of nails, fatigue, irritability and neurological damage. Cirrhosis
of the liver
, pulmonary edema
, and death
can occur with extreme concentrations of selenium.
came to the conclusion that high concentrations of selenium in the highly mobile selenate
state was the primary cause of deformation and abnormality of animals at the Kesterson Reservoir. In 1987, the site was declared a toxic waste dump. Remediation of the site began shortly after researchers reported their findings. The San Luis drain was closed and the Kesterson reservoir was drained. The Kesterson Reservoir was capped with soil in the late 1980s and closed as a wildlife area.
Because of the potential of other locations experiencing a similar fate (also known as "the Kesterson Effect"), the United States Geological Survey created the San Joaquin Valley Drainage Program and National Irrigation Water Quality Program to study the effects of irrigation drain water on surrounding ecosystems. 14 locations have been identified that have the potential to affect ecosystems in similar ways to that of the Kesterson Reservoir.
San Luis National Wildlife Refuge
The San Luis National Wildlife Refuge in the San Joaquin Valley of central California is one of the great remnants of a historically bountiful wintering grounds for migratory waterfowl on the Pacific Flyway...
. The site gained national attention during the later half of the 20th century due to selenium
Selenium
Selenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...
toxicity
Toxicity
Toxicity is the degree to which a substance can damage a living or non-living organisms. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
and rapid die off of migratory waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
, 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...
, insects, plants and 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...
within the Kesterson Reservoir.
Background
The Kesterson Reservoir is located in the heart of the San Joaquin ValleySan Joaquin Valley
The San Joaquin Valley is the area of the Central Valley of California that lies south of the Sacramento – San Joaquin River Delta in Stockton...
in central California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
. The reservoir and San Luis National Wildlife Refuge are located in western Merced County
Merced County, California
Merced County , is a county located in the Central Valley of the U.S. state of California, north of Fresno and southeast of San Jose. As of the 2010 census, the population was 255,793, up from 210,554 at the 2000 census. The county seat is Merced...
, approximately 18 miles (29 km) north of Los Banos
Los Banos
Los Banos could refer to:*Los Banos, California, United States*Los Baños, Laguna, Philippines...
, California. The refuge includes four units, the Kesterson, Freitas, Bear Creek and original San Luis Units. The refuge is 26609 acres (107.7 km²) and includes a variety of wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....
and riparian habitat which supports a large variety of waterfowl, mammals and other wildlife.
The San Joaquin Valley has been considered by historian Kevin Starr
Kevin Starr
Kevin Starr is an American historian, best known for his multi-volume series on the history of California, collectively called "Americans and the California Dream."-Life:Kevin Starr was born in San Francisco, California....
as being "the most productive unnatural environment on Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
" as approximately 25% of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
’ agricultural products originate from the valley. Examples of the agricultural exports from this area include grapes, cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....
, nuts
Nut (fruit)
A nut is a hard-shelled fruit of some plants having an indehiscent seed. While a wide variety of dried seeds and fruits are called nuts in English, only a certain number of them are considered by biologists to be true nuts...
, citrus
Citrus
Citrus is a common term and genus of flowering plants in the rue family, Rutaceae. Citrus is believed to have originated in the part of Southeast Asia bordered by Northeastern India, Myanmar and the Yunnan province of China...
, and vegetables. Cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
and sheep ranching also contribute to the agricultural output of the area.
The San Joaquin Valley is bordered on the west by the Coast Range and on the east by the Sierra Nevada mountains. The Coast Range include Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
and Tertiary
Tertiary
The Tertiary is a deprecated term for a geologic period 65 million to 2.6 million years ago. The Tertiary covered the time span between the superseded Secondary period and the Quaternary...
marine sedimentary rocks. Weathering and oxidation of the Moreno Formation, a black marine shale, produces Pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...
, FeS2, and Iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
Selenide
Selenide
A selenide is a chemical compound in which selenium serves as an anion with oxidation number of −2 , much as sulfur does in a sulfide. The chemistry of the selenides and sulfides are similar....
, FeSe2. As the weathered products concentrate in evaporative minerals and salts, selenates (for instance, Na2SeO4 · 10 H2O or Na2Mg(SeO4)2 · 4 H2O) and Sulfates (Na2SO4 · 10 H2O or Na2Mg(SO4)4 · 4 H2O) can form. This results in selenium salts and selenium rich soils that are sloughed off the mountains via debris flows or landslides into the San Joaquin valley. Additionally, the San Joaquin Valley has a shallow aquifer
Aquifer
An aquifer is a wet underground layer of water-bearing permeable rock or unconsolidated materials from which groundwater can be usefully extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology...
bounded by impermeable clays.
The climate of the San Joaquin Valley does not lend itself well to agricultural production and results in large scale 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...
projects in order to keep fertile farms in operation. According to some estimates, the climate of the San Joaquin Valley has approximately 10 inches (254 mm) of precipitation and over 90 inches (2,286 mm) of evaporation annually. In order to keep the area productive, irrigation is a requirement.
A side effect of irrigation in the San Joaquin Valley was that ground water levels began to rise over time. This led to a condition where excess water was accumulating and starting to harm crops. In 1968, the Bureau of Reclamation created the 134 km long San Luis Drain and the Kesterson Reservoir. Farmers in the San Joaquin valley installed drainage tiles in an effort to maintain water tables at 2 meters. The Kesterson reservoir was completed in 1971 by the Bureau of Reclamation and consisted of 12 evaporation ponds within the Kesterson National Wildlife Refuge.
Contamination
Due to the concentration of selenium in the Coast Range west of the San Joaquin Valley, selenium was transported into the valley and naturally accumulated on the valley floor. Selenium toxicity began to become a problem shortly after drainage tiles were installed. Initially (from 1971–78), the reservoir was receiving all fresh water. After 1978, this began to change and by 1981, all water coming into the Kesterson Reservoir was salineSaline water
Saline water is a general term for water that contains a significant concentration of dissolved salts . The concentration is usually expressed in parts per million of salt....
drain water. Contributing to the salinity of the drain water was the highly-mobile ion of selenium, selenate
Selenate
The selenate ion is SeO42–.Selenates are analogous to sulfates and have similar chemistry. They are highly soluble in aqueous solutions at ambient temperatures....
, SeO42-. Selenium begin to bioaccumulate in the waterfowl and wildlife that used the reservoir.
Prior to 1981, the Kesterson Reservoir supported a wide variety of life, including several species of fish. After 1981, the reservoir only supported the most saline tolerant mosquito fish. The habitat change occurred quickly and also included algal blooms and disappearing waterfowl. In 1982, the United States Fish and Wildlife Service
United States Fish and Wildlife Service
The United States Fish and Wildlife Service is a federal government agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats...
began a study to determine the cause for declining wildlife use at the reservoir. Selenium concentrations at these locations were found to be greater than 1400 micrograms per liter.
Selenium toxicity
SeleniumSelenium
Selenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...
is an element that behaves very similarly to sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
. It is required for humans in small amounts, less than 55 micrograms. Selenium is the required element in the amino acids selenocysteine
Selenocysteine
Selenocysteine is an amino acid that is present in several enzymes .-Nomenclature:...
and selenomethionine
Selenomethionine
Selenomethionine is an amino acid containing selenium. The L-enantiomer of selenomethionine, known as Se-met and Sem, is a common natural food source of selenium. In vivo, selenomethionine is randomly incorporated instead of methionine and is readily oxidized. Its antioxidant activity arises from...
. In humans, selenium is seen in antioxidant
Antioxidant
An antioxidant is a molecule capable of inhibiting the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent. Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions. When...
enzymes such as gluthathione peroxidases and thioredoxin reductase
Thioredoxin reductase
Thioredoxin Reductases are the only known enzymes to reduce thioredoxin . Two classes of thioredoxin reductase have been identified: one class in bacteria and some eukaryotes and one in animals. Both classes are flavoproteins which function as homodimers...
. It helps in the daily functioning of the thyroid gland. Selenium deficiency can lead to Keshan disease
Keshan disease
Keshan disease is a congestive cardiomyopathy caused by a combination of dietary deficiency of selenium and the presence of a mutated strain of Coxsackievirus, named after Keshan County of Heilongjiang province, Northeast China, where symptoms were first noted. These symptoms were later found...
, which is potentially fatal. Keshan disease includes such symptoms as myocardial necrosis which leads to weakening of the heart. If a diet is low in selenium and iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
, Keshan-Beck disease may develop, which leads to immune deficiency, making the body less resilient to nutritional, biochemical and infectious diseases. Selenium is necessary for the conversion of the thyroid hormone thyroxine
Thyroxine
Thyroxine, or 3,5,3',5'-tetraiodothyronine , a form of thyroid hormones, is the major hormone secreted by the follicular cells of the thyroid gland.-Synthesis and regulation:...
(T4) into triiodothyronine
Triiodothyronine
Triiodothyronine, C15H12I3NO4, also known as T3, is a thyroid hormone. It affects almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate....
. A deficiency of selenium can cause hypothyroidism
Hypothyroidism
Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
, which results in extreme fatigue, mental slowing, Goitre
Goitre
A goitre or goiter , is a swelling in the thyroid gland, which can lead to a swelling of the neck or larynx...
, cretinism
Cretinism
Cretinism is a condition of severely stunted physical and mental growth due to untreated congenital deficiency of thyroid hormones usually due to maternal hypothyroidism.-Etymology and use of cretin:...
and miscarriage
Miscarriage
Miscarriage or spontaneous abortion is the spontaneous end of a pregnancy at a stage where the embryo or fetus is incapable of surviving independently, generally defined in humans at prior to 20 weeks of gestation...
.
In locations around the world with low selenium concentrations in soil, some research has indicated a higher incidence of HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
/AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...
. Lack of selenium strongly correlates with the progression of AIDS and the risk of death.
In concentrations greater than 400 micrograms per day, selenosis may develop. The symptoms of selenosis include gastrointestinal disorders, hair loss, sloughing of nails, fatigue, irritability and neurological damage. Cirrhosis
Cirrhosis
Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules , leading to loss of liver function...
of the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
, pulmonary edema
Pulmonary edema
Pulmonary edema , or oedema , is fluid accumulation in the air spaces and parenchyma of the lungs. It leads to impaired gas exchange and may cause respiratory failure...
, and death
Death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
can occur with extreme concentrations of selenium.
Remediation
In 1981, ranchers in the San Joaquin Valley near the San Luis drain and Kesterson Reservoir discovered livestock deformities and death. Two years later, there was a large migratory waterfowl die off. Many birds were severely deformed. The Bureau of Reclamation, United States Fish and Wildlife Service and United States Geological SurveyUnited States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
came to the conclusion that high concentrations of selenium in the highly mobile selenate
Selenate
The selenate ion is SeO42–.Selenates are analogous to sulfates and have similar chemistry. They are highly soluble in aqueous solutions at ambient temperatures....
state was the primary cause of deformation and abnormality of animals at the Kesterson Reservoir. In 1987, the site was declared a toxic waste dump. Remediation of the site began shortly after researchers reported their findings. The San Luis drain was closed and the Kesterson reservoir was drained. The Kesterson Reservoir was capped with soil in the late 1980s and closed as a wildlife area.
Because of the potential of other locations experiencing a similar fate (also known as "the Kesterson Effect"), the United States Geological Survey created the San Joaquin Valley Drainage Program and National Irrigation Water Quality Program to study the effects of irrigation drain water on surrounding ecosystems. 14 locations have been identified that have the potential to affect ecosystems in similar ways to that of the Kesterson Reservoir.
- Tulare Basin, San Joaquin ValleySan Joaquin ValleyThe San Joaquin Valley is the area of the Central Valley of California that lies south of the Sacramento – San Joaquin River Delta in Stockton...
, California - Salton SeaSalton SeaThe Salton Sea is a shallow, saline, endorheic rift lake located directly on the San Andreas Fault, predominantly in California's Imperial Valley. The lake occupies the lowest elevations of the Salton Sink in the Colorado Desert of Imperial and Riverside counties in Southern California. Like Death...
, California - Middle Green River BasinGreen River (Utah)The Green River, located in the western United States, is the chief tributary of the Colorado River. The watershed of the river, known as the Green River Basin, covers parts of Wyoming, Utah, and Colorado. The Green River is long, beginning in the Wind River Mountains of Wyoming and flowing...
, Utah - Stillwater Management Area, Nevada
- Kendrick Reclamation ProjectNorth Platte RiverThe North Platte River is a major tributary of the Platte River and is approximately long counting its many curves, It travels about distance. Its course lies in the U.S...
, Wyoming - Gunnison RiverGunnison RiverThe Gunnison River is a tributary of the Colorado River, long, in the Southwest state of Colorado. It is the fifth largest tributary of the Colorado River, with a mean flow of 4320 ft³/s .-Description:...
Basin-Grand Valley Project, Colorado - San Juan River area, New Mexico
- Sun RiverSun RiverThe Sun River is a tributary of the Missouri River in the Great Plains, approximately 130 mi long, in Montana in the United States....
area, Montana - RivertonRiverton, WyomingRiverton is a city in Fremont County, Wyoming, United States. It is both the largest city in the county and the largest within the historical boundaries of the Wind River Indian Reservation. The city's population was 9,310 at the 2000 census...
Reclamation Project, Wyoming - Belle Fourche Reclamation, South Dakota
- Dolores-Ute Mountain Area, Colorado
- Lower Colorado River valley, Texas
- Middle Arkansas River BasinArkansas RiverThe Arkansas River is a major tributary of the Mississippi River. The Arkansas generally flows to the east and southeast as it traverses the U.S. states of Colorado, Kansas, Oklahoma, and Arkansas. The river's initial basin starts in the Western United States in Colorado, specifically the Arkansas...
, Colorado-Kansas - Pine River areaLa Plata County, ColoradoLa Plata County is the fourteenth most populous of the 64 counties of the State of Colorado of the United States. The county was named for the La Plata River and the La Plata Mountains. "La plata" is the Spanish language word for "silver". The United States Census Bureau estimated that the...
, Colorado.