Most of the country's coastal waters are free of serious chemical contamination, but local pockets of toxic pollution persist in most major urban areas, a government report says.
The six-year study by the National Oceanic and Atmospheric Administration, released Tuesday, concluded that chemical pollution has stabilized or even declined at most of 287 coastal sites examined in 23 states from Maine to Hawaii.The findings tracked the presence of 11 toxic chemicals - including lead, mercury, PCBs and pesticides such as DDT - in mussels, oysters, bottom-feeding fish and sediment.
"There are local pockets (of severe contamination), but it's not a general problem all over the United States," Thomas O'Connor, author of the NOAA report, concluded. He said the trend appears to be that chemical contamination of most coastal waters "seems to be decreasing."
But O'Connor said the study was aimed at assessing pollution over broad regions and not in smaller "hot spots" that are close to industrial emissions.
High levels of contamination for at least six of the 11 pollutants studied were found at 29 of the sites studied, most of them urban areas, the report said.
High contamination levels were found in Boston Harbor, along the New York-New Jersey coast, Baltimore Harbor and at San Diego, Los Angeles and Seattle, the report said.
While overall assessment indicated vast coastal waters were relatively free of chemical contamination, many severely polluted local areas were not included in the study.
For example, while the coastal areas in the Gulf of Mexico were found to be noticeably clean of toxic pollution, specific waterways near industrial sources of emissions such as the Houston Ship Channel were not part of the study.
Other well-known contamination sites not studied included the Chelsea River in Boston, the Cerritos Channel in Los Angeles, the Black Rock Harbor in Bridgeport, Conn., and some industrial waterways in the Seattle-Tacoma area, officials acknowledged.
O'Connor said the NOAA study was aimed, instead, at getting a picture of water contamination at sites that are generally "representative" of a broader region, not specific industrial waterways.
"If you go right near the industrial areas . . . you will get very high levels of contamination," he said.
The study tested for traces of metals such as lead, cadmium, mercury, copper and zinc as well as the pesticides DDT and chlordane, PCBs and toxic hydrocarbons. Many of these are severely restricted or banned altogether from use but continue to be found in coastal waters, the study said.
"While these new findings suggest some improvements in the health of the marine environment, the prognosis isn't all good," said Charles Ehler, director of NOAA's office of oceanography and marine assessment.
Here are test sites where samples of sediment and examination of marine life indicated high levels of contamination from a majority of the 11 chemicals under study. The study was conducted between 1984 and 1989 by the National Oceanic and Atmospheric Administration.
Deer Island, Dorchester Bay, Hingham Bay, Quincy Bay (all part of Boston Harbor).
Sheffield Island (part of Long Island Sound).
West Long Island Sound.
Mamaroneck, Hempstead Harbor, Throgs Neck (all part of Long Island Sound).
Jamaica Bay, Upper Bay, Lower Bay (all part of Hudson-Raritan Estuary).
Raritan Bay (portion in Hudson-Raritan Estuary).
Sandy Hook (part of New York Bight).
Watson Bayou (part of St. Andrew Bay).
Shirk Point (part of Choctawhatchee Bay).
South San Diego Bay.
Harbor Island (in San Diego Bay).
North San Diego Bay.
San Pedro Canyon.
Royal Palms Park (in Palos Verdes).
West Santa Monica Bay.