Among all of the substances quantified in Phase 2, the concentrations of the dioxins were most highly 

 correlated with amphipod survival. The scatterplot of the data showed a consistent pattern of decreas- 

 ing survival with increasing 2,3,7, 8-tcdd concentrations (Figure 40). All of the samples that were 

 highly toxic to the amphipods had 2,3, 7, 8-tcdd concentrations that exceeded the 100 pg/g guideline 

 proposed by the U.S. EPA (1993). 



The concentrations of all the dioxin, furan, and PCB congeners for which toxicity equivalency factors 

 were available (Barnes et al., 1991; Kutzet al., 1990) were normalized to (multiplied by) the appropri- 

 ate TEFs and the total cumulative TEQs were determined. Amphipod survival was highly correlated 

 with the total cumulative TEQs (Figure 41). Also, all of the samples that exceeded the U.S. EPA 

 (1993) guideline of 100 pg/g were highly toxic to the amphipods. Amphipod survival dropped to 50% 

 or less in samples with total dioxins TEQs of 150 pg/g or more. However, the sample with the highest 

 TEQ concentration was not sample 26, in which amphipod survival was zero. 



The relationships between amphipod survival and the concentrations of both lead and zinc were rela- 

 tively strong and consistent (Figures 42-43). All of the samples with lead concentrations that exceeded 

 the ERM value (Long et al., 1995) were highly toxic (survival <80%). Also, all except one sample with 

 zinc concentrations above the ERM value were highly toxic. Long et al. (1995) reported relatively 

 high confidence in the ERM values for both of the elements. However, two samples in which survival 

 was 0.0% and 20% had relatively low concentrations of both lead and zinc. The very high concentra- 

 tions of PCBs, dioxins, and other chlorinated hydrocarbons probably were more important in these 

 samples than the trace elements. Also, one sample with a very high concentration of zinc (>700 ug/g) 

 had relatively high amphipod survival (80%). Based upon these data, lead and zinc may have contrib- 

 uted to the observed toxicity in some of the samples. 



The correlations between the concentrations of PAHs and amphipod survival were relatively poor, 

 especially when compared to the strong correlations observed in the data from Phase 1 . The concentra- 

 tions of high molecular weight PAHs were relatively high in the samples that caused low amphipod 

 survival; however, this pattern was not consistent (Figure 44). For example, the HPAH concentration 

 in sample 26 was relatively low (less than the ERM value of 9600 ng/g) and one sample in which 

 amphipod survival was relatively high had the highest concentration of these compounds. Among the 

 three compounds for which EPA has developed SQCs, fluoranthene was most strongly correlated with 

 amphipod survival. However, the correlation between amphipod survival and fluoranthene concentra- 

 tions was not significant and the pattern was inconsistent (Figure 45). Three samples had fluoranthene 

 concentrations that either equalled or exceeded the SQC; amphipod survival was relatively high in one 

 and very low in the other. Based upon these data, it does not appear that the PAHs contributed substan- 

 tially to the observed toxicity in many of the Newark Bay samples. 



Of the 20 samples that were subjected to chemical analyses, 4 were not significantly different from 

 controls in the tests of amphipod survival, whereas 16 were significantly different from controls and 

 amphipod survival was less than 80% of the control survival. The average concentrations of the 2,3,7,8- 

 tcdd and dioxin TEQs that co-occurred with the nontoxic and the toxic samples are compared in Table 

 33. In addition, the average concentrations of these compounds in the toxic samples were compared 

 with the sediment guideline proposed by the U.S. EPA (1993). The average concentration of 2,3,7,8- 

 tcdd in the toxic samples exceeded the average concentration in the nontoxic samples by a factor of 

 10.6 and exceeded the guideline by a factor of 2.7. The concentrations of the dioxin TEQs, co-planar 

 PCB TEQs, and total cumulative TEQs in the toxic samples exceeded the concentrations in the non- 



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