The dominant species in the area, a tube-building amphipod, was found 

 in great density over the test area. The recolonization by these amphi- 

 pods and worms indicated that the spoil surfaces did not contain large 

 amounts of toxic materials. Species diversity varied spatially. Dis- 

 solved oxygen was lacking in the pore water of the spoil sediments, but 

 no anoxic conditions developed in the overlying water. Furthermore, 

 hydrocarbons and heavy metals did not appear in high concentrations in 

 the dumping grounds. 



The study recommended that the dumping area is suitable for further 

 disposal of relatively cohesive and unpolluted material, but that addi- 

 tional investigations should be made of the ocean bottom currents, of 

 the sediment characteristics, and of the rehabilitation and recoloni- 

 zation of the spoil area by benthic organisms. 



2. Delaware Bay 



Since 1961, the City of Philadelphia has disposed digested sludge 

 11.5 nautical miles (21.3 km) off Cape May, N.J. and Cape Henlopen out- 

 side Delaware Bay. The dumping grounds are 60 feet deep, and cover a 

 rectangular area 1 mile by 2 miles. (Guarino, 1967; Civil Engineering, 

 1968; Baxter, 1959; City of Philadelphia, 1968). In January 1971, the 

 City contracted research studies with the Franklin Institute Laboratories 

 and the Jefferson Medical College Laboratories: (a) to provide more de- 

 tailed environmental description of the dumping grounds; (b) to determine 

 the environmental and ecological effects of the dumping operations; and 

 (c) to determine the existence of pathogenic micro-organisms in the area. 



The interim results were summarized by Baxter, et al , (1971) as: 



a. Sediment samples taken from the Center of the disposal site and 

 the immediate vicinity consisted of clean sand along with gravel and 

 shell fragments. 



b. In all sediment samples taken in and around the disposal area, 

 no black sludge or samples emitting hydrogen sulfide were found. 



c. At the center of the sludge disposal area, starfish, sand dollars, 

 hermit crabs, and snails were found in good health. A good variation of 

 species was observed at all stations. 



d. Fish specimens collected at the disposal site included winter 

 flounder, mackeral, stargazer, long horn sculpin, and spiny dogfish. 



e. Dissolved oxygen measurements of bottom, middle and surface 

 waters at various points within and around the site showed no signs of 

 oxygen depletion or sag. 



f. Coliform levels in all bottom, mid and surface waters were zero. 



g. There were no indications of significant concentrations of heavy 

 metals in surf clams and other macrofauna collected in the area. 



