identifed non-polar organics associated with oil and grease as a source 

 of toxicity in sediments in the upstream portions of the Calumet Sag 

 Channel and Lake Calumet. 



4.4 Toxicity Identification Evaluation - Phase III 



Toxicity in sediment porewaters from the upper Illinois Waterway 

 is correlated with total ammonia concentrations (r = 0.85, Figure 4.3). 

 Jones and Lee (1988) found that of more than 30 contaminants measured in 

 sediments from New York Harbor, only ammonia concentrations correlated to 

 observed toxicity in grass shrimp. Ankley et al . (1990) identified 

 ammonia as a major toxicant in sediments from the lower Fox River and 

 Green Bay, Wisconsin. 



The fingernail clam, Musculium transversum, is sensitive to ammo- 

 nia. Anderson, Sparks and Paparo (1978) found that un-ionized ammonia 

 concentrations of 0.08-0.09 mg/1 inhibited the cilia on the gills of the 

 clams, and the growth of the clams in the laboratory was reduced at 

 concentrations between 0.20 and 0.34 mg/1 NH3-N. Un-ionized ammonia 

 concentrations greater than these are likely to occur in sediment pore- 

 waters of the upper Illinois Waterway, based on total ammonia concentra- 

 tions we measured (23.8-59.8 mg/1 NH3-N) and pH ranges known to occur in 

 the water column. The clams must draw oxygenated water from the water 

 column down their burrows to survive, and in doing so, they might shift 

 the pH from the low levels characteristic of anaerobic sediments to 

 higher levels characteristic of the water column, thereby increasing the 

 fraction of the total ammonia that exists in the toxic un-ionized form. 



In summary, several lines of evidence lead to the conclusion that 

 ammonia in sediment porewater was limiting macroinvertebrate populations 

 in the Illinois Waterway at the time this study was conducted. First, 



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