May 12, 2008
Coastal Waters Show Decrease In Contaminants
Concerns remain with continuing chemical inputs
NOAA scientists today 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 U.S. 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.
"We need to ensure the safety of our coastal waters for the rich resources they provide," says John H. Dunnigan, NOAA assistant administrator of the National Ocean Service. "This program shows that although our coasts are under tremendous pressure, policymakers and the public are able to work together to produce positive results."
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 (PAHs) from motor vehicles and shipping activities continue to flow into coastal waters daily. Because NOAA has been monitoring these areas for extended periods, baseline data already exist to help define the extent of environmental degradation. For example, PAH levels following the 2007 Cosco Busan oil spill in San Francisco Bay showed concentrations at the monitoring site near the spill were the highest ever recorded.
- Flame retardants known as PBDEs are a new class of contaminants currently being evaluated by NOAA to determine whether they are increasing in coastal waters and what effects they may have on both marine and human health. NOAA plans to issue a report on flame retardants in coastal waters later this year.
NOAA's Mussel Watch Program, founded in 1986, is the nation's longest continuous national contaminant-monitoring program in U.S. coastal waters. The program keeps collected tissue samples frozen so that overlooked or newly emerging contaminants can be retroactively analyzed, as is currently being done with flame retardants.
"The Mussel Watch Program 20-year assessment is a concise and informative review of contaminant monitoring in the nation's coastal waters," said Jack Schwartz with Massachusetts Marine Fisheries. "This report should well serve readers who may not necessarily be conversant with scientific literature on contaminant monitoring and fate and effects."
On the Net:
The report is available here
NOAA Center for Coastal Monitoring and Assessment