SEWAGE CONTAMINATION IN SEDIMENTS BENEATH A DEEP-OCEAN DUMP SITE OFF NEW-YORK

The world's largest discharge of municipal sewage sludge to surface wa ters of the deep sea has caused measurable changes in the concentratio n of sludge indicators in sea-floor sediments, in a spatial pattern wh ich agrees with the predictions of a recent sludge deposition model. S ilver, linear alkylbenzenes, coprostanol, and spores of the bacterium Clostridium perfringens, in bottom sediments and in near-bottom suspen ded sediment, provide evidence for rapid settling of a portion of disc harged solids, accumulation on the sea floor, and biological mixing be neath the water-sediment interface. Biological effects include an incr ease in 1989 of two species of benthic polychaete worm not abundant at the dump site before sludge dumping began in 1986. These changes in b enthic ecology are attributed to the increased deposition of utilizabl e food in the form of sludge-derived organic matter.