ENVIRONMENTAL IMPLICATIONS 163 



and which can be used to address coal conversion. It includes a 

 description and a discussion of two major approaches that might be 

 taken (including their strengths and weaknesses), a summary of the 

 environmental data available on the various organic components of 

 coal-conversion effluents, and a suggested approach that we have 

 adopted for assessing the environmental implications of coal- 

 conversion effluents. 



Historically, the potential environmental hazards of aqueous 

 effluents have been evaluated by one of two approaches: (1) 

 identifying and subsequently evaluating all the various effluent 

 components or (2) testing the whole effluent. 



The first approach produces the data necessary to attain the 

 second and third major goals of ecological research. The types of 

 research involved in this approach include, in addition to determining 

 sublethal effects and the mechanisms of effects, determining the 

 ultimate fate of a compound within the environment and the critical 

 environmental pathways that lead to exposure of various biota. This 

 type of research can be referred to as mechanistic. It is essential in 

 developing predictive capabilities. Unfortunately, when the number 

 of compounds in an effluent stream is large, identifying all of them 

 and testing each individually and in concert becomes too costly and 

 time consuming. Such is the case in coal conversion, where perhaps 

 thousands of compounds may be present in a particular effluent 

 stream (Shults, 1976). 



The second approach, testing the whole effluent, enables us to 

 determine the acute toxicity of various effluent streams. Such data 

 reveal the relative toxicity of the streams although they do not allow 

 determination of what component(s) is(are) most toxic, and this 

 information is extremely important in assessing treatability and 

 developing control technology. This approach is particularly useful 

 for coal conversion where, as mentioned earlier, a great many 

 processes are currently under development. Thus, if he can produce 

 and deliver relevant data within the time frame the developing 

 technology follows, the ecologist has a unique opportunity to help 

 determine the ultimate form of- the technology(ies). For example, if 

 decisions on whether to pursue a technology are to be made in early 

 1980, then ecological-effects data pertaining to the technology must 

 be developed before that time. 



The toxic components of complex chemical mixtures (primarily 

 petroleum and synthetic petroleum) have been determined in two 

 ways. The most common method uses boiling point to separate a 

 mixture into smaller, similar fractions. Moore and Dwyer (1974), 

 reviewing the literature on the toxicity of aromatic hydrocarbons to 



