Maximum Contaminant Level

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Maximum Contaminant Levels (MCLs) are standards that are set by the United States Environmental Protection Agency (EPA) for drinking water quality. [1] [2] An MCL is the legal threshold limit on the amount of a substance that is allowed in public water systems under the Safe Drinking Water Act (SDWA). The limit is usually expressed as a concentration in milligrams or micrograms per liter of water. [3]

Standardization or standardisation is the process of implementing and developing technical standards based on the consensus of different parties that include firms, users, interest groups, standards organizations and governments Standardization can help to maximize compatibility, interoperability, safety, repeatability, or quality. It can also facilitate commoditization of formerly custom processes. In social sciences, including economics, the idea of standardization is close to the solution for a coordination problem, a situation in which all parties can realize mutual gains, but only by making mutually consistent decisions. This view includes the case of "spontaneous standardization processes", to produce de facto standards.

United States Environmental Protection Agency Agency of the U.S. Federal Government

The Environmental Protection Agency (EPA) is an independent agency of the United States federal government for environmental protection. President Richard Nixon proposed the establishment of EPA on July 9, 1970 and it began operation on December 2, 1970, after Nixon signed an executive order. The order establishing the EPA was ratified by committee hearings in the House and Senate. The agency is led by its Administrator, who is appointed by the President and approved by Congress. The current Administrator is former Deputy Administrator Andrew R. Wheeler, who had been acting administrator since July 2018. The EPA is not a Cabinet department, but the Administrator is normally given cabinet rank.

Drinking water water safe for consumption

Drinking water, also known as potable water, is water that is safe to drink or to use for food preparation. The amount of drinking water required varies. It depends on physical activity, age, health issues, and environmental conditions. Americans, on average, drink one litre of water a day and 95% drink less than three litres per day. For those who work in a hot climate, up to 16 litres a day may be required. Water is essential for life.

Contents

Federal MCL development

Chart of Regulatory Analysis Processes under the Safe Drinking Water Act SDWA Regulatory Analysis Processes - Flowchart - EPA 2016.png
Chart of Regulatory Analysis Processes under the Safe Drinking Water Act

To set a Maximum Contaminant Level for a contaminant, EPA first determines how much of the contaminant may be present with no adverse health effects. This level is called the Maximum Contaminant Level Goal (MCLG). MCLGs are non-enforceable public health goals. The legally enforced MCL is then set as close as possible to the MCLG. The MCL for a contaminant may be higher than the MCLG because of difficulties in measuring small quantities of a contaminant, a lack of available treatment technologies, or if EPA determines that the costs of treatment would outweigh the public health benefits of a lower MCL. In the last case, EPA is permitted to choose an MCL that balances the cost of treatment with the public health benefits. [4] MCLs require monitoring, remediation, and public notice when standards are exceeded. [2] As of 2016, there were 88 MCLs for different organic and inorganic chemicals. [2]

Health effects are changes in health resulting from exposure to a source. Health effects are an important consideration in many areas, such as hygiene, pollution studies, occupational safety and health, nutrition and health sciences in general. Some of the major environmental sources of health effects are air pollution, water pollution, soil contamination, noise pollution and over-illumination.

Water purification process of removing undesirable chemicals, biological contaminants, suspended solids from water

Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water fit for specific purposes. Most water is purified and disinfected for human consumption, but water purification may also be carried out for a variety of other purposes, including medical, pharmacological, chemical, and industrial applications. The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination; and the use of electromagnetic radiation such as ultraviolet light.

For some contaminants, EPA establishes a Treatment Technique (TT) instead of an MCL. TTs are enforceable procedures that drinking water systems must follow in treating their water for a contaminant. [4]

MCLs and TTs are known jointly as "National Primary Drinking Water Regulations" (NPDWRs), or primary standards. [5]

Some contaminants may cause aesthetic problems with drinking water, such as the presence of unpleasant tastes or odors, or cosmetic problems, such as tooth discoloration. Since these contaminants do not cause health problems, there are no legally enforceable limits on their presence in drinking water. However, EPA recommends maximum levels of these contaminants in drinking water. These recommendations are called "National Secondary Drinking Water Regulations" (NSDWRs), or secondary standards. [4] [6]

Tooth discoloration abnormal tooth color, hue or translucency

Tooth discoloration is abnormal tooth color, hue or translucency. External discoloration is accumulation of stains on the tooth surface. Internal discoloration is due to absorption of pigment particles into tooth structure. Sometimes there are several different co-existent factors responsible for discoloration.

MCLs issued by states

Some state laws and regulations use the term "maximum contaminant level" to refer to MCLs promulgated within a state pursuant either to the federal SDWA or state law; for example, the New Jersey Safe Drinking Water Act. [7] In some cases, a state may issue an MCL for a contaminant that has not been regulated by EPA under federal law. For example, in 2018 New Jersey promulgated an MCL for perfluorononanoic acid (PFNA). [8] [9]

Perfluorononanoic acid, or PFNA, is a synthetic perfluorinated carboxylic acid and fluorosurfactant that is also an environmental contaminant found in people and wildlife along with PFOS and PFOA.

See also

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Safe Drinking Water Act Principal federal law in the United States intended to ensure safe drinking water for the public

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References

  1. United States. Safe Drinking Water Act of 1974. 42 U.S.C.   § 300f(3)
  2. 1 2 3 Joseph Cotruvo, Victor Kimm, Arden Calvert. “Drinking Water: A Half Century of Progress.” EPA Alumni Association. March 1, 2016.
  3. "National Primary Drinking Water Regulations (Summary tables)". Ground Water and Drinking Water. Washington, DC: U.S. Environmental Protection Agency (EPA). 2018-03-22.
  4. 1 2 3 "How EPA Regulates Drinking Water Contaminants". EPA. 2018-06-06.
  5. EPA. "National Primary Drinking Water Regulations." Code of Federal Regulations, 40 CFR Part 141.
  6. EPA. "National Secondary Drinking Water Regulations." Code of Federal Regulations, 40 CFR Part 143.
  7. State of New Jersey. New Jersey Safe Drinking Water Act. L.1977, c. 224, s. 1, effective September 17, 1977. NJSA 58:12A-1.
  8. Fallon, Scott (2018-09-06). "New Jersey becomes first state to regulate dangerous chemical PFNA in drinking water". North Jersey Record. Woodland Park, NJ.
  9. "Maximum Contaminant Levels (MCLs) for Perfluorononanoic Acid and 1,2,3-Trichloropropane; Private Well Testing for Arsenic, Gross Alpha Particle Activity, and Certain Synthetic Organic Compounds". New Jersey Register. Trenton, NJ: New Jersey Department of Environmental Protection. 2018-09-04. 50 N.J.R. 1939(a).