Drinking Water Quality and Contamination
ARSENIC, FLUORIDE, TRICHLOETHYLENE, MERCURY, COPPER, ENDOCRINE DISRUPTORS, NITRATE: RISKS AND STANDARDS
Naturally occurring and man-made contaminants in drinking water are of concern to all of us. Recently, an NRC report found "substantial evidence that trichloroethylene in drinking water might cause impaired intrauterine growth at environmentally relevant concentrations" [view report]. Another report, which reviewed the U.S. Environmental Protection Agency's (EPA) drinking water standard for fluoride, "concluded unanimously that the present MCLG [maximum contaminant level goal] of 4 mg/L for fluoride should be lowered" to lower the risk of developing severe enamel fluorosis [view report]. A 2001 report on arsenic [view report] found that men and women who daily consume water containing 20 parts per billion of arsenic have about a 7 in 1,000 increased risk of developing bladder or lung cancer during their lifetime. Perchlorate (a component of rocket fuel and fireworks) [view report], copper [view report], and nitrate and nitrite [view report] in drinking water have also been studied in depth by the NRC. A study of the toxicological effects of methylmercury [view report] summarizes laboratory experiments involving exposure of rats to methylmercury through drinking water. And the state of the science for endocrine disruptors in the environment was summarized in a 2000 report [view report].
CONTAMINANT CANDIDATE LIST
In the United States, the EPA is responsible for much of the drinking water regulation, and the NRC has contributed three reports to its efforts to periodically develop a drinking water contaminant candidate list (CCL). Its first report [view report] recommended a phased decision-making process to set priorities and decide which potential contaminants should receive more regulatory attention, monitoring, and research. The second report [view report] urged that a scientifically defensible and transparent process with increased opportunities for public input be used to develop its future CCLs of unregulated contaminants that are likely to pose risks to drinking water. Its third report [view report] recommended process for creating future CCLs consisting of simple screening criteria and expert judgment to winnow down the list of thousands of potential contaminants, followed by individual assessment to evaluate the likelihood that they would actually pose a public health risk.
CHALLENGES TO WATER SYSTEMS
Small water-supply systems [view report] often cannot afford the equipment and qualified operators necessary to ensure compliance with various safe drinking water regulations. Improving the quality of water service to these communities may involve streamlining pilot testing requirements to make technologies more affordable, consolidating the management and financial administration of small systems, and improving training programs. However, even large systems like New York City [view report] can face huge expenses installing water treatment, and have a motivation to protect their source water.
To support a country's population and economic goals, there needs to be a steady supply of high quality fresh water. Desalination and water purification is just one of the many technologies being explored to harness the water for potable use [view report].
Books Related to Drinking Water Quality and Contamination
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