a Long and Morgan (1990) 

 b Long et al. (1995) 

 c U.S. EPA (1994) 

 d Swartz et al. (1994) 



na = no applicable guidelines 



The average concentrations of the trace metals in the toxic samples rarely exceeded the averages in the 

 nontoxic samples by a great degree, and, except for mercury, were lower than the respective ERM 

 value (Table 35). The toxic/nontoxic ratios ranged from 0.8 to 2.9 for the metals. The toxic/nontoxic 

 ratios for each element were similar whether quantified as total extractable metal or as AVS simulta- 

 neously extracted metal. Although the average concentration of mercury in the toxic samples was 

 elevated relative to the ERM value, Long et al. (1995) reported only a moderate degree of confidence 

 in this guideline, suggesting that it should be higher. The concentrations of un-ionized ammonia were 

 lower in the toxic samples than in the nontoxic samples. 



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