Phosphorus Remains Biggest Challenge to Coastal Waters

The U.S. Environmental Protection Agency (EPA) released the 2010 National Coastal Condition Assessment showing that more than half of the nation’s coastal and Great Lakes near-shore waters are rated good for biological and sediment quality, while about one-third are rated good for water quality.

In almost all coastal waters, however, contaminants in fish tissue pose a threat to sensitive predator fish, birds and wildlife.

“Since more than half the nation’s population lives near coastal waters, and that number is increasing every year, it is important for us to understand the condition of these productive and fragile habitats so we can properly manage and protect them,” said Joel Beauvais, EPA Deputy Assistant Administrator for Water. “The latest science confirms we must keep paying close attention to our coastal waters, reduce the pollutants that are harming water quality, and protect those areas still in good condition.”

The summarized findings are:

  • Biological quality is rated good in 56 percent of coastal and Great Lakes near-shore waters. Healthy communities of bottom-dwelling macroinvertebrates are supported in these waters.
  • Water quality is rated fair in 48 percent of coastal and Great Lakes waters and good in 36 percent when measuring phosphorus, nitrogen, water clarity, chlorophyll, and dissolved oxygen concentrations. The most widespread stressor for water quality is phosphorus.
  • Sediment quality is rated good in 55 percent of coastal and Great Lakes near-shore waters based on low levels of sediment contaminants and sediment toxicity.
  • Ecological fish tissue quality is rated good for less than one percent of the nation’s waters. This means there is a potential threat to the most sensitive predators (fish, birds and wildlife) that consume fish in most waters.
  • Change in conditions were mixed between 2005-2006 and 2010. Water quality remained unchanged, biological quality improved 17 percent, and sediment quality declined by 22 percent. 

Excessive phosphorus, potentially from sources such as sewage and fertilizers, is the greatest contributor to the poor water quality rating in coastal waters. Selenium is the greatest contributor to the poor ecological fish tissue rating. It is a naturally occurring mineral in the environment that may be increasing due to human activities. For more information visit

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