toxic (Brosnan and O'Shea, 1993). In 18 samples tested in 1990 from the Arthur Kill and vicinity, 

 amphipod mortality ranged from 18 to 61% (Aqua Survey, 1990a, 1990b). Five of nine samples col- 

 lected in 1990 were toxic to amphipods during the first phase of the EMAP survey conducted by U.S. 

 EPA (Schimmel et al., 1994). 



During Phase 1 of this survey, toxicity in 1 17 sediment samples was determined with three complimen- 

 tary tests performed in the laboratory. Four toxicity end-points were determined among the three tests. 

 Toxicity end-points included survival of amphipods, survival of bivalve larvae, morphological devel- 

 opment of bivalve larvae, and metabolic activity of a bioluminescent bacterium. During Phase 2, 57 

 additional samples from Newark Bay and vicinity were tested with the amphipod survival test. 



All four test end-points provided a wide range in response from the least toxic to the most toxic station. 

 In Phase 1, amphipod survival ranged from 0.0% in three samples to 99.0%. In Phase 2, amphipod 

 survival ranged from 0.0% in two samples to 100%. Bivalve embryo survival ranged from 16.1% to 

 over 100% relative to controls. Bivalve normal development ranged from 0.0% in two samples to 

 1007o in many samples. The Microtox EC50s ranged from 0.30 mg/ml to over 32.6 mg/ml. All four 

 end-points indicated that some of the stations and some of the sites were significantly more toxic than 

 the control sediments. 



The toxicity data developed for each station and site during Phase 1 are summarized in Table 37. A 

 single asterisk was assigned to those stations and sites that were significantly different from controls in 

 each test. Two asterisks were assigned where the numerical results were significantly different from 

 controls and were less than or equal to 80% of the control response. 



Based upon the results of all four test end-points combined, the samples from zones A (lower Hudson 

 River), G (lower Raritan River), I (central Raritan Bay), K (southern Raritan Bay), and M (outer bay, 

 New York Bight) were among the least toxic. Samples from these areas often were not toxic in any of 

 the tests, or in only one or two of them. Furthermore, toxicity test results rarely were less than 80% of 

 the control responses. Among the most toxic samples were those from zones B (western Long Island 

 Sound), C (upper East River), D (lower East River), and F (Newark Bay/Arthur Kill). Samples from 

 these areas often were highly toxic as indicated by toxicity in multiple tests and responses less than 

 80% of the control response. 



Table 37. Summary of toxicity test results for each station and site sampled during Phase 1. 



112 



