2.0 PROJECT GOALS AND GENERAL APPROACH 



The primary goal was to identify the toxicants in the sediments of 

 the Illinois Waterway. In addition, we hoped to identify upstream- 

 downstream patterns in toxicity and follow toxicity gradients upstream 

 to sources. 



We tested the toxicity of sediments taken widely along the entire 

 length of the Illinois Waterway, and from one reference site on the 

 Upper Mississippi River (Figures 1.1 and 1.2). Next, sediments that 

 exhibited toxicity were subjected to Phase I Toxicity Identification and 

 Evaluation (TIE) procedures (pH adjustment, addition of a chelating 

 agent, etc.), to characterize the toxicants (see Figures 1.3 and 1.4). 

 If the toxicity at all sites varied the same way in response to the 

 Phase I treatments, we would know we were dealing with one class of 

 toxicants, or perhaps even one major toxicant, and we could focus 

 additional sampling on the most toxic reach in the hope of identifying 

 the major source. At the same time. Phase II and Phase III TIE 

 procedures would confirm the identity of the toxicant or at least narrow 

 the range of suspect chemicals. However, if Phase I testing indicated 

 that different classes of toxicants occurred in different reaches of 

 the waterway, then we would have a much more complex task of identifying 

 multiple toxicants and multiple sources--a task that might extend well 

 beyond the budget and time limitations of this research. 



