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SUMMARY 



This reviews the Biological Assessment prepared by EPA pursuant to 

 Section 7 of the Endangered Species Act, and entitled Assessment of Potential 

 Impact of the MWRA Outfall on Endangered Spec:es. The sections dealing with 

 potential nutrient impacts upon phytoplankton community structure and 

 dynamics and toxic bloom events are focused upon in this critique. The EPA 

 assessments of the potential nutrient-phytoplankton interactions accompanying 

 installation of the MWRA outfall site are seriously marred by numerous 

 misunderstandings of phytoplankton processes and their regulation; failure to 

 distinguish between mass balance effects, phytoplankton community 

 organization and species-specific processes; incomplete consideration of 

 available literature; the analytical approach used in data selection, 

 interpretation and in s/'/u extrapolation is seemingly slanted to favor the basic 

 conclusion reached - i.e., of non-endangerment, and the conclusions reached 

 are basically anecdotally-based rather than scientifically rigorous. It is 

 uncertain to what extent, and whether these shortcomings falsify the conclusion 

 arrived at by EPA: that the new outfall is unlikely to adversely impact 

 endangered species. EPA's acknowledged absence of key data sets, inability 

 to quantify complex factor interactions, the reliance on a "weight-of-evidence" 

 approach to arrive at conclusions (for which statistical confidence limits cannot 

 be derived), and shortcomings of the nutrient-phytoplankton analyses needed 

 for extrapolation to assess associated upper trophic level dynamics, however, 

 challenge whether this conclusion has the sound scientific basis required to 

 resolve this issue, or is an artifact. 



