EPA sets first-ever water quality criteria for nutrients, methylmercury
The Environmental Protection Agency has taken a significant step to protect waters from excessive nutrients that can choke waterways and lead to algae blooms, including Pfiesteria and red tide, resulting in fish kills and potentially harmful human health effects.
Dec. 28, 2000—The Environmental Protection Agency has taken a significant step to protect waters from excessive nutrients that can choke waterways and lead to algae blooms, including Pfiesteria and red tide, resulting in fish kills and potentially harmful human health effects.
For the first time, the agency is setting water quality criteria which serve as recommendations to states and tribes for water quality standards for nutrients, including nitrogen and phosphorous. States are expected to adopt or revise their nutrient standards by 2004, based on the new criteria.
The new criteria are expected to significantly reduce nutrients in the nation's waterways. In a l998 water quality report to Congress, nutrients were listed as a leading cause of water pollution. About half of the nation's waters surveyed by states do not adequately support aquatic life because of excess nutrients.
In 1998, states reported that excessive nutrients have degraded almost 3.5 million acres of lakes and reservoirs and over 84,000 miles of rivers and streams to the point where they no longer meet basic uses such as supporting healthy aquatic life.
At the same time today, EPA is protecting human health from methylmercury, the form of mercury that is found in contaminated fish. The toxic methylmercury is taken up by plant and aquatic life and accumulates in the fish which can be consumed by humans. Methylmercury is toxic to the nervous system.
EPA is issuing under the Clean Water Act its first water quality criterion for methylmercury to be used by states in determining methylmercury levels in fish tissue. The new methylmercury water quality criteria are based on a new risk assessment (a reference dose) that EPA has developed in response to last summer's recommendation by the National Academy of Sciences. Both the new criteria and the new reference dose are based on updated scientific data on environmental fate and human health effects of methylmercury.