The amount of contaminants and metals found in the mid-Atlantic?s oyster population are decreasing, reflecting a nationwide trend in coastal waters, according to a report released Monday.
The federal National Oceanic and Atmospheric Administration?s 20-year study examined the levels of 140 trace metals and organic compounds in the tissues of mussels and oysters in U.S. coastal areas, including the Chesapeake Bay.
“The good news is they are decreasing,” said Gunnar Lauenstein, manager of the NOAA Mussel Watch Program, of the contaminants.
The program monitors metals such as arsenic and contaminants such as oil-related compounds known as PAHs.
Lauenstein said trace elements will exist, but human activity such as shipping increases some of them.
The report shows a decrease in the pesticide DDT and the industrial chemicals PCBs in mussel and oyster tissues from 1986 to 2006.
PCBs, which act as flame retardants, DDT and PAHs are common organic chemical contaminants found in the Chesapeake Bay watershed, according to the Chesapeake Bay Program, a regional partnership focused on Bay restoration. Mercury is the most common metal in the watershed.
Mussels and oysters are good indicators of contamination levels because they are sedentary organisms that filter the water, Lauenstein said.
