Since the zeolite selectively removes ammonia, these results support 

 identification of ammonia as the toxicant. 



The suspect nonpolar organics at sites CS307.4 and DP281.1 seemed 

 to have different chemical and physical properties because no toxicity 

 could be obtained from DP281.1 by column absorption and elution with 

 methanol alone, whereas CS307.4 did yield toxicity with the methanol 

 extraction (Table 4.6). Moreover, toxic materials were eluted by a wider 

 range of methylene chloride/methanol mixtures (20-50%) from the CS307.4 

 sample than from the DP277.0 sample (25-40%, Table 4.7). Also, the 

 greatest toxicity in porewater sample DP281.1 was associated with resi- 

 due left on the filters after passage of porewater, whereas the greatest 

 toxicity in sample CS307.4 was in supernatant left after centrifuging 

 out most of the particles (Table 4.6). The DP277.0 elutriate contained 

 no organics detectable by gc-mass spectrography, whereas 34 organic 

 compounds were detected in the CS307.4 elutriate (Table 4.8). This was 

 surprising because the DP277.0 elutriates contained toxicity (Table 

 4.7), but perhaps there were undetectable quantities of nonpolar organ- 

 ics that were highly toxic. 



The elutriates from sample CS307.4 contained different combina- 

 tions of nonpolar organics (Table 4.8). No compounds were found above 

 the detection limits in the 20% fraction. The 25% fraction contained 

 the polycyclic aromatic hydrocarbon (PAH) naphthalene. The 30% fraction 

 contained primarily cyclic and branched hydrocarbons (cyclohexane, 

 octane) and PAHs. The 35-50% fractions contained numerous long chain 

 hydrocarbons such as heptadecane, undecane and dodecane. The 40 and 45% 

 fractions also contained the alkenes, eicosene and dotriacontanol . In 

 general, toxicity in these samples appears to be primarily due to 

 petroleum hydrocarbons and PAHs. Scubauer-Berigan and Ankley (1991) 



36 



