A sampling program was developed to determine whether the PCBs known to have been present in the operations of the two GE plants located upriver in the Hudson River Estuary were still detectable after 20 years. Bivalve molluscs were collected from 98 Peterson grab samples and subsequently analyzed for PCBs. In all but one case, the PCBs detected were found to be Aroclor 1254, that which is typically considered to be linked to the upsteam GE contamination. Concentrations were discovered in excess of both federal USEPA levels and New York State standards for fish consumption. The concentrations found in the clams sampled range from 0.056 g/L to 840 g/L. Statistical regressions were performed for the water quality indicators of salinity, dissolved oxygen, percent oxygen saturation, pH, and eH, all of which were measured at the time of sampling. Other variables including trace metals and latitude were also considered in the analysis in order to determine any predictive indicators of high concentrations of PCBs.