p>0.05, n=50). The concentration of un-ionized ammonia exceeded the detection limit (0.35 wg/1) in 

 seven of the samples and the maximum recorded concentration was 620 «g/l. Three of the samples 

 exceeded the no- observed-effects concentration and none equalled or exceeded the unionized ammo- 

 nia LC50 for A. abdita (Figure 36) reported by Kohn et al. (1994). 



The correlations between amphipod survival and the concentrations of chlorinated organic compounds 

 and total organic carbon are listed and compared in Table 29. Nearly all of the pesticides and PCB 

 groups were significantly correlated with toxicity to the amphipods. Compounds that were very highly 

 correlated with amphipod survival included dieldrin (expressed both in dry weight and organic car- 

 bon), p, p'-DDE, and total PCBs (estimated by GC, as the total of quantified congeners, and by GC/ 

 MS). Amphipod survival was more highly correlated with the DDE isomers than with the DDT iso- 

 mers. The correlations with endrin were not significant. The correlations with total organic carbon 

 also were not significant. If the number of variables tested (18) were accounted for, only those corre- 

 lations shown with "**" would be significant. 



Table 29. Spearman-rank correlations (Rho, corrected for ties) between percent amphipod sur- 

 vival and the concentrations of chlorinated organic compounds in Newark Bay sediments (n=20). 



ns = not significant (p>0.05). *p<0.05, **p<0.001 



The correlations between amphipod survival and the concentrations of nearly all the dioxin and furan 

 compounds were highly significant (Table 30). The concentrations were expressed as units of dry 

 weight for individual compounds. Also, the concentrations of selected compounds were multiplied by 

 the respective 2,3,7,8-tcdd toxicity equivalency factors of Barnes et al. (1991) for co-planar PCBs and 

 Kutz et al. (1990) for dioxins and furans and summed to estimate the total toxicity equivalency quo- 

 tients (TEQ). The correlations were particularly strong for 2,3,7,8-tcdd, 2,3,7,8-tcdf, the cumulative 

 2,3,7,8-tcdd TEQ for total PCBs, and the total cumulative TEQ for dioxins, furans, and PCBs. Amphi- 

 pod survival was significantly correlated with tcdd-equivalent concentrations determined in H4IIE rat 

 hepatoma bioassays of the whole Fl extract and several of the extract fractions, but not with the F5 

 fraction (PAHs). If the number of variables tested (28) were accounted for, only those correlations 

 shown with "**" would be significant. 



97 



