Since 1986, the National Status and Trends Mussel Watch program has monitored chemical contaminants in bivalve mollusks (mussels) in coastal sites across the U.S, including nine in Long Island Sound.
Concentrations of chemicals in mussel tissues are related to the levels of chemicals in the water that they inhabit and in the food that they filter from the water. Therefore, if chemical concentrations in the water and/or in food sources decline, chemical concentrations in the mussels themselves should decline as well.
Overall, no chemical or metal has increased in concentration along Connecticut harbors. Contamination has been decreasing at many sites whose use of DDT and chlordane have been banned. In New York a majority of sites have seen a decline in chemical and heavy metal contamination. Port Jefferson has seen significantly declining trends in chemical contamination, but increasing trends in two metals, arsenic and copper.