WASHINGTON (AP) -- Chemical contamination has abated along vast stretches of U.S. coastal waters, but high levels of toxic pollution are still found in major cities and industrial "hot spots," including Baltimore Harbor, the government said yesterday.
The report by the National Oceanic and Atmospheric Administration stemmed from a six-year study of chemical traces found in mussels, oysters, bottom-feeding fish and sediment at 287 coastal sites in 23 states, from Maine to Hawaii.
"There are local pockets [of severe contamination], but it's not a general problem all over the United States," concluded Thomas O'Connor, author of the NOAA report. He said the trend appeared to be that chemical contamination of most coastal waters "seems to be decreasing."
But the study, which tested for 11 chemicals, included a number of caveats aimed at making clear that while nationwide coastal water pollution may not be as severe as believed, there are many regions of the country where high levels of toxic chemicals continue to contaminate stretches of water.
The study did not include the examination of some "hot spots" already known to have high levels of chemical pollution because of their proximity to industrial facilities.
And while the overall assessment indicated that vast stretches of coastal waters are relatively free of chemical contamination, high levels of toxic chemicals continue to be found in waterways near such urban areas as Baltimore, Boston, the New York-New Jersey coastal area, San Diego, Los Angeles and Seattle.
At 29 of the 287 sites examined, high levels of contamination were found from at least six of the 11 toxic pollutants the investigators looked for. These included Baltimore Harbor, Boston Harbor and Salem Harbor in Massachusetts, West Long Island Sound and Jamaica Bay in New York and Elliott Bay in Washington.
Mr. O'Connor said the study was aimed at getting a picture of water contamination at sites that are more "representative" of a broader region, not specific industrial waterways.
The study tested for traces of such metals as lead, cadmium, mercury, copper and zinc as well as the pesticides DDT and chlordane, PCBs and toxic hydrocarbons.