International standards for drinking water
Encyclopedia
Drinking water quality standards describes the quality parameters set for drinking water
. Despite the truism that every human on this planet needs drinking water to survive and that water can contain many harmful constituents
, there are no universally recognised and accepted international standards for drinking water. Even where standards do exist, and are applied, the permitted concentration of individual constituents may vary by as much as ten times from one set of standards to another.
Many developed countries specify standards to be applied in their own country. In Europe this includes the Drinking water directive
and in the USA the United States Environmental Protection Agency
(EPA) establishes down standards as required by the Safe Drinking Water Act
. For countries without a legislative or administrative framework for such standards, the World Health Organisation publishes guidelines on the standards that should be achieved
Where standards do exist most are expressed as guidelines or targets and very few have any legal basis or are subject to enforcement. The European Drinking Water Directive and the Safe Water Act in the USA are two exceptions where there is a requirement to legally comply with specific standards.
In Europe this includes a requirement for member states to enact appropriate local legislation to mandate the directive in each country. Routine inspection and, where required, enforcement is enacted by means of penalties imposed by the European Commission
on non-compliant nations.
Countries with guideline values as their standards include Canada
which has guideline values for a relatively small suite of parameters, New Zealand
where there is a legislative basis but water providers have to make "best endeavours" to comply with the standards and Australia
. In addition a number of standards documents also make reference to the statistical treatment of results, dealing with temporal and seasonal variations, summation of related parameters and treatment of apparently aberrant results.
value such as the average concentration of copper is 2 mg/l. Many countries not only specify parametric values that may have health impacts but also specify parametric values for a range of constituents that by themselves are unlikely to have any impact on health. These include colour, turbidity
, pH
and the organoleptic
parameters (taste and smell).
It is possible and technically acceptable to refer to the same parameter in different ways that may appear to suggest a variation in the standard required. For example, Nitrite
may be measured as Nitrite ion
or expressed as N
. A standard of Nitrite as N of 1.4 mg/l would be equal to a nitrite ion concentration of 4.6 mg/l - an apparent difference of nearly three fold.
guidance and may adopt USA standards.
For man-made pollutant
s potentially occurring in drinking water the following standards are proposed.
Organic species:
" indicates that no standard has been identified by editors of this article and ns indicates that no standard exists.
Drinking water
Drinking water or potable water is water pure enough to be consumed or used with low risk of immediate or long term harm. In most developed countries, the water supplied to households, commerce and industry is all of drinking water standard, even though only a very small proportion is actually...
. Despite the truism that every human on this planet needs drinking water to survive and that water can contain many harmful constituents
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....
, there are no universally recognised and accepted international standards for drinking water. Even where standards do exist, and are applied, the permitted concentration of individual constituents may vary by as much as ten times from one set of standards to another.
Many developed countries specify standards to be applied in their own country. In Europe this includes the Drinking water directive
Drinking water directive
The European Drinking Water Directive , Council Directive 98/83/EC concerns the quality of water intended for human consumption and forms part of the regulation of Water supply and sanitation in the European Union....
and in the USA the United States Environmental Protection Agency
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
(EPA) establishes down standards as required by the Safe Drinking Water Act
Safe Drinking Water Act
The Safe Drinking Water Act is the principle federal law in the United States intended to ensure safe drinking water for the public. Pursuant to the act, the Environmental Protection Agency is required to set standards for drinking water quality and oversee all states, localities, and water...
. For countries without a legislative or administrative framework for such standards, the World Health Organisation publishes guidelines on the standards that should be achieved
Where standards do exist most are expressed as guidelines or targets and very few have any legal basis or are subject to enforcement. The European Drinking Water Directive and the Safe Water Act in the USA are two exceptions where there is a requirement to legally comply with specific standards.
In Europe this includes a requirement for member states to enact appropriate local legislation to mandate the directive in each country. Routine inspection and, where required, enforcement is enacted by means of penalties imposed by the European Commission
European Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
on non-compliant nations.
Countries with guideline values as their standards include Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
which has guideline values for a relatively small suite of parameters, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
where there is a legislative basis but water providers have to make "best endeavours" to comply with the standards and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
Range of standards
Although drinking water standards are frequently referred to as if they are simple lists of parametric values, standards documents also specify sampling location choice, sampling methods, laboratory analytical methods and laboratory AQCAnalytical quality control
Analytical quality control, commonly shortened to AQC refers to all those processes and procedures designed to ensure that the results of laboratory analysis are consistent, comparable, accurate and within specified limits of precision....
. In addition a number of standards documents also make reference to the statistical treatment of results, dealing with temporal and seasonal variations, summation of related parameters and treatment of apparently aberrant results.
Parametric values
A parametric value in this context is most commonly the concentration of a substance, e.g. 30 mg/l of Iron. It may also be a count such as 500 E. coli per litre or a statisticalStatistics
Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
value such as the average concentration of copper is 2 mg/l. Many countries not only specify parametric values that may have health impacts but also specify parametric values for a range of constituents that by themselves are unlikely to have any impact on health. These include colour, 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....
, pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
and the organoleptic
Organoleptic
Organoleptic is an adjective used to refer to the aspects of food or other substances as experienced by the senses, including taste, sight, smell, and touch.-USDA uses:...
parameters (taste and smell).
It is possible and technically acceptable to refer to the same parameter in different ways that may appear to suggest a variation in the standard required. For example, Nitrite
Nitrite
The nitrite ion has the chemical formula NO2−. The anion is symmetric with equal N-O bond lengths and a O-N-O bond angle of ca. 120°. On protonation the unstable weak acid nitrous acid is produced. Nitrite can be oxidised or reduced, with product somewhat dependent on the oxidizing/reducing agent...
may be measured as Nitrite ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
or expressed as N
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...
. A standard of Nitrite as N of 1.4 mg/l would be equal to a nitrite ion concentration of 4.6 mg/l - an apparent difference of nearly three fold.
Australian standards
Drinking water quality standards in Australia have been developed by the Australian Government National Health and Medical Research Council (NHMRC) in the form of the Australian Drinking Water Guidelines. These guidelines provide contaminant limits (pathogen, aesthetic, organic, inorganic and radiological) as well as guidance on applying limits for the management of drinking water in Australian drinking water treatment and distribution systems.European Union standards
The following parametric standards are included in the Drinking Water directive and are expected to be enforced by appropriate legislation in every country in the European Union. Simple parametric values are reproduced here but in many cases the original directive also provides caveats and notes about many of the values given.- AcrylamideAcrylamideAcrylamide is a chemical compound with the chemical formula C3H5NO. Its IUPAC name is prop-2-enamide. It is a white odourless crystalline solid, soluble in water, ethanol, ether, and chloroform. Acrylamide is incompatible with acids, bases, oxidizing agents, iron, and iron salts...
0.10 μg/l - AntimonyAntimonyAntimony is a toxic chemical element with the symbol Sb and an atomic number of 51. A lustrous grey metalloid, it is found in nature mainly as the sulfide mineral stibnite...
5.0 μg/l - ArsenicArsenicArsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...
10 μg/l - BenzeneBenzeneBenzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
1.0 μg/l - Benzo(a)pyrene 0.010 μg/l
- BoronBoronBoron is the chemical element with atomic number 5 and the chemical symbol B. Boron is a metalloid. Because boron is not produced by stellar nucleosynthesis, it is a low-abundance element in both the solar system and the Earth's crust. However, boron is concentrated on Earth by the...
1.0 mg/l - BromateBromateThe bromate anion, BrO, is a bromine-based oxoanion. A bromate is a chemical compound that contains this ion. Examples of bromates include sodium bromate, , and potassium bromate, .Bromates are formed many different ways in municipal drinking water...
10 μg/l - CadmiumCadmiumCadmium 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...
5.0 μg/l - ChromiumChromiumChromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
50 μg/l - CopperCopperCopper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
2.0 mg/l - CyanideCyanideA cyanide is a chemical compound that contains the cyano group, -C≡N, which consists of a carbon atom triple-bonded to a nitrogen atom. Cyanides most commonly refer to salts of the anion CN−. Most cyanides are highly toxic....
50 μg/l - 1,2-dichloroethane1,2-DichloroethaneThe chemical compound 1,2-dichloroethane, commonly known by its old name of ethylene dichloride , is a chlorinated hydrocarbon, mainly used to produce vinyl chloride monomer , the major precursor for PVC production. It is a colourless liquid with a chloroform-like odour...
3.0 μg/l - EpichlorohydrinEpichlorohydrinEpichlorohydrin is an organochlorine compound and an epoxide. This is a colorless liquid with a pungent, garlic-like odor, moderately soluble in water, but miscible with most polar organic solvents. Epichlorohydrin is a highly reactive compound and is used in the production of glycerol, plastics,...
0.10 μg/l - FluorideFluorideFluoride is the anion F−, the reduced form of fluorine when as an ion and when bonded to another element. Both organofluorine compounds and inorganic fluorine containing compounds are called fluorides. Fluoride, like other halides, is a monovalent ion . Its compounds often have properties that are...
1.5 mg/l - LeadLeadLead 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...
10 μg/l - MercuryMercury (element)Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
1.0 μg/l - NickelNickelNickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
20 μg/l - NitrateNitrateThe 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...
50 mg/l - NitriteNitriteThe nitrite ion has the chemical formula NO2−. The anion is symmetric with equal N-O bond lengths and a O-N-O bond angle of ca. 120°. On protonation the unstable weak acid nitrous acid is produced. Nitrite can be oxidised or reduced, with product somewhat dependent on the oxidizing/reducing agent...
0.50 mg/l - PesticidePesticidePesticides 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 0.10 μg/l - Pesticides - Total 0.50 μg/l
- Polycyclic aromatic hydrocarbons 0.10 μg/l Sum of concentrations of specified compounds;
- SeleniumSeleniumSelenium 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...
10 μg/l - Tetrachloroethene and Trichloroethene 10 μg/l Sum of concentrations of specified parameters
- TrihalomethaneTrihalomethaneTrihalomethanes are chemical compounds in which three of the four hydrogen atoms of methane are replaced by halogen atoms. Many trihalomethanes find uses in industry as solvents or refrigerants. THMs are also environmental pollutants, and many are considered carcinogenic...
s — Total 100 μg/l Sum of concentrations of specified compounds - Vinyl chlorideVinyl chlorideVinyl chloride is the organochloride with the formula H2C:CHCl. It is also called vinyl chloride monomer, VCM or chloroethene. This colorless compound is an important industrial chemical chiefly used to produce the polymer polyvinyl chloride . At ambient pressure and temperature, vinyl chloride...
0.50 μg/l
United States standards
In the USA the legislation controlling drinking water quality is the Safe Water Act which is implemented federally by the EPA. However many individual States also apply their own standards which may be more rigorous or include additional parameters. Standards set by the EPA in the USA are not international standards since they apply to a single country. However many countries look to the USA for appropriate scientific and public healthPublic health
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals" . It is concerned with threats to health based on population health...
guidance and may adopt USA standards.
World Health Organisation guidelines
These guidelines include the following recommended limits on naturally occurring constituents that may have direct adverse health impact:- Arsenic 10μg/l
- Barium 700μg/l
- Boron 2400μg/l
- Chromium 50μg/l
- Fluoride 1500μg/l
- Selenium 40μg/l
- Uranium 30μg/l
For man-made pollutant
Pollutant
A pollutant is a waste material that pollutes air, water or soil, and is the cause of pollution.Three factors determine the severity of a pollutant: its chemical nature, its concentration and its persistence. Some pollutants are biodegradable and therefore will not persist in the environment in the...
s potentially occurring in drinking water the following standards are proposed.
- Cadmium 3μg/l
- Mercury 6μg/l For inorganic mercury
Organic species:
- Benzene 10μg/l
- Carbon tetrachloride 4μg/l
- 1,2-Dichlorobenzene 1000μg/l
- 1,4-Dichlorobenzene 300μg/l
- 1,2-Dichloroethane 30μg/l
- 1,2-Dichloroethene 50μg/l
- Dichloromethane 20μg/l
- Di(2-ethylhexyl)phthalate 8 μg/l
- 1,4-Dioxane 50μg/l
- Edetic acid 600μg/l
- Ethylbenzene 300 μg/l
- Hexachlorobutadiene 0.6 μg/l
- Nitrilotriacetic acid 200μg/l
- Pentachlorophenol 9μg/l
- Styrene 20μg/l
- Tetrachloroethene 40μg/l
- Toluene 700μg/l
- Trichloroethene 20μg/l
- Xylenes 500μg/l
Comparison of parametric values
The following table provides a comparison of a selection of parameters concentrations listed by WHO, the European Union and the EPA." indicates that no standard has been identified by editors of this article and ns indicates that no standard exists.
| Parameter | World Health Organization | European Union | United States |
|---|---|---|---|
| Acrylamide | “ | 0.10 μg/ | “ |
| Arsenic | 10μg/l | 0.1 μg/l | 10μg/l |
| Antimony | ns | 5.0 μg/l | “ |
| Barium | 700μg/l | ns | “ |
| Benzene | 10μg/l | 1.0 μg/l | “ |
| Benzo(a)pyrene | “ | 0.010 μg/l | “ |
| Boron | 2.4mg/l | 1,0 mg/l | “ |
| Bromate | “ | 10 μg/l | “ |
| Cadmium | 3μg/l | 5,0 μg/l | “ |
| Chromium | 50μg/l | 50 μg/l | “ |
| Copper | “ | 2.0 mg/l | “ |
| Cyanide | “ | 50 μg/l | “ |
| 1,2-dichloroethane | “ | 3.0 μg/l | “ |
| Epichlorohydrin | “ | 0.10 μg/l | “ |
| Fluoride | 1.5 mg/l | 1.5 mg/l | 4 mg/l |
| Lead | “ | 10 μg/l | 15 μg/l |
| Mercury | 6μg/l | 1.0 μg/l | “ |
| Nickel | “ | 20 μg/l | “ |
| Nitrate | “ | 50 mg/l | “ |
| Nitrite | “ | 0.50 mg/l | “ |
| Pesticides (individual) | “ | 0.10 μg/ l | “ |
| Pesticides — Total | “ | 0.50 μg/l | “ |
| Polycyclic aromatic hydrocarbons l | “ | 0.10 μg/ | “ |
| Selenium | 40μg/l | 10 μg/l | “ |
| Tetrachloroethene and Trichloroethene | 40μg/l | 10 μg/l | “ |