Polychlorinated biphenyls and other organochlorine compounds in marine zooplankton off the east coast of Newfoundland, Canada

Marine zooplankton samples collected in 1993 and 1994 at 25 stations along the east coast of Newfoundland and Labrador were analyzed for polychlorinated biphenyls (PCBs) and persistent organochlorine (OC) compounds. Concentrations of these compounds were low (<1 ng/g wet weight). A few trichloro-, tetrachloro- and pentachlorobiphenyl congeners were detected in zooplankton. Hexachlorobenzene (HCB), α-hexachlorocyclohexane (αHCH) and some components of technical chlordane were also detected in the samples. Dichlorodichlorophenylethylene (DDE) and Dichlorodiphenyltrichloroethane (DDT) were consistently present in zooplankton at approximately equal concentrations. Analysis of variance with data calculated on either a wet weight or a lipid-normalized basis indicated that there were no significant differences in contaminant concentrations that could be attributed to sampling year or to the towing methods used to collect samples. Principal component analysis (PCA) of analytical data indicated that there were no spatial trends evident in either the concentrations or patterns of contamination. The patterns of PCB and OC contamination are consistent with the patterns previously reported in zooplankton from the Arctic. The concentrations of trace contaminants reported in this study are well below the concentrations reported for North Atlantic zooplankton sampled in the 1970s.