NOAA: Coastal Waters Show Contaminant Decline
National Oceanic and Atmospheric Administration scientists on May 12 released a 20-year study showing that environmental laws enacted in the 1970s are having a positive effect on reducing overall contaminant levels in coastal waters of the United States.
However, the report points to continuing concerns with elevated levels of metals and organic contaminants found near urban and industrial areas of the coasts.
"It's interesting to note that pesticides, such as DDT, and industrial chemicals, such as PCBs, show significant decreasing trends around the nation, but similar trends were not found for trace metals," said Gunnar Lauenstein, manager of the NOAA Mussel Watch program. "What is of concern is that there are contaminants that continue to be problematic, including oil-related compounds from motor vehicles and shipping activities."
The report, "NOAA National Status and Trends Mussel Watch Program: An Assessment of Two Decades of Contaminant Monitoring in the Nation's Coastal Zone from 1986-2005," is the first that presents national, regional, and local findings in a quick reference format, suitable for use by policymakers, scientists, resource managers, and the public. The findings are the result of monitoring efforts that analyze 140 different chemicals in U.S. coastal and estuarine areas, including the Great Lakes.
Significant findings from this report include the following:
• Decreasing trends nationally of the pesticide DDT are documented with a majority of the sites monitored along the Southern California coast.
• Decreasing trends also were found for the industrial chemicals PCBs. The Hudson-Raritan Estuary, one area of the country where some of the highest concentrations of these chemicals were found, now shows 80 percent of monitored sites with significantly decreasing trends for this pollutant.
• Tributyl-tin, a biocide used as a compound to reduce or restrict the growth of marine organisms on boat hulls, was found to have greater than anticipated consequences as it affected not only the targeted organisms but also other marine and fresh water life as well. First regulated in the 1980s, this compound is now decreasing nationally.
The NOAA Mussel Watch Program also quantifies contaminants that are still entering the nation's waters and two major groups raise concern:
• Oil-related compounds (polyaromatic hydrocarbons, PAHs) from motor vehicles and shipping activities continue to flow into coastal waters daily.
• Flame retardants known as PBDEs are a new class of contaminants being evaluated to determine whether they are increasing and what effects they may have on marine and human health.