U.S. Coastal Waters Less Toxic Than 20 Years Ago

Oil related compounds from motor vehicles and shipping activities continue to flow into coastal waters daily, NOAA reports. These compounds, known as polycyclic aromatic hydrocarbons, or PAHs, have been monitored by NOAA scientists for decades so baseline data 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.

The Department of Health and Human Services has determined that some PAHs "may reasonably be expected to be carcinogens."

Gunnar Lauenstein is manager of the NOAA Mussel Watch program. (Photo courtesy NOAA)

"What is of concern is that there are contaminants that continue to be problematic, including oil-related compounds from motor vehicles and shipping activities," said Gunnar Lauenstein, manager of the NOAA Mussel Watch program, which produced the report.

The longest continuous national contaminant-monitoring program in U.S. coastal waters, the Mussel Watch program analyzes chemical and biological contaminant trends in sediment and bivalve tissue collected at over 280 coastal sites from 1986 to present.

"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."

The NOAA Mussel Watch scientists have monitored and analyzed 140 different chemicals in U.S. coastal and estuarine areas, including the Great Lakes.

"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 Lauenstein.

Scientist in the field packages oysters for shipment back to the laboratory where they are analyzed for contaminants. (Photo courtesy NOAA)

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.

"We need to ensure the safety of our coastal waters for the rich resources they provide," said John 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."

The report shows decreasing trends nationally of the pesticide DDT, although a majority of the sites monitored are along the Southern California coast.

Decreasing trends also were found for the industrial chemicals polychlorinated biphenyls, or PCBs. The Hudson-Raritan Estuary in New York and New Jersey, one area of the country where some of the highest concentrations of these chemicals were found, now shows 80 percent of monitored sites with 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 freshwater life as well. First regulated in the 1980s, this compound is now decreasing nationally.

Flame retardants known as PBDEs are a new class of contaminants currently being evaluated by the Mussel Watch Program to determine whether they are increasing in coastal waters and what effects they may have on both marine and human health.

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.

NOAA plans to issue a report on flame retardants in coastal waters later this year.

Copyright Environment News Service (ENS) 2008. All rights reserved.