Trends in organic contaminant distributions in oysters from the Gulf of Mexico

Sediments and oyster samples were collected from 48 to 65 sites in the gulf of Mexico as part of the NOAA National Status and Trends Mussel Watch Program. These samples were analyzed for a suite of organic contaminants including polynuclear aromatic hydrocarbons (PAHs), chlorinated pesticides and polychlorinated biphenlys (PCBs). Oyster samples from 44 of these sites were collected in three consecutive years. The most commonly observed trends are sites with constant contaminant concentrations within the constraints of natural variability for the three years. There are, however, sites where measurable changes occur in the three sampling years, indicating pulses of contamination at these sites.