Significantly high concentrations of metals present in the City of Philadelphia sewage sludge can be found on occasion at points in the sediments in and near the sludge release site. Several bands with high concentrations of metals, in association with high organic carbon, have been partially identified and have persisted for at least 14 months in and adjacent to the southern part of the site. Ambient concentrations of the metals in question have been derived by statistical comparisons over a 3 year period. Polychlorinated biphenyls (PCB's) were widely distributed in concentrations that may be inimical to marine organisms with indicated cyclical inputs, possibly from the coastal zone. Mortalities of the mahogany clam, Arctica islandica, were indicated at loci in and near the ocean dumping activity. Detailed bathymetry of the impacted area south of the site indicates geomorphic features may affect the aggregation of dumped materials. Statistically significant changes of the benthic infaunal communities are occurring in the impacted area south of the sewage sludge release site. Mollusks in the vicinity of the site appear to harbor bacteria of sanitary significance.

U.S. Environmental Protection Agency, Region III, Annapolis Field Office. "July 1977." Includes bibliographical references (p. 167-168). "EPA 903/9-77-029."