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Evaluating impacts of pulp and paper mill process changes on bioactive contaminant loading to St. Louis Bay.
Citation:
Randolph, E., G. Ankley, J. Berninger, J. Cavallin, E. Eid, M. Hughes, M. Kahl, K. Jensen, J. Mayasich, A. Parrella, A. Schroeder, K. Stevens, AND Dan Villeneuve. Evaluating impacts of pulp and paper mill process changes on bioactive contaminant loading to St. Louis Bay. Midwest SETAC, Madison, WI, March 14 - 16, 2016.
Impact/Purpose:
not applicable
Description:
As a convergence point for human waste streams, wastewater treatment plants are recognized as point sources through which contaminants originating from domestic, industrial, and commercial activities enter surface waters. Effluent from the Western Lake Superior Sanitary District (WLSSD), which discharges into the St. Louis River (MN and WI, USA), has previously been shown to exhibit both estrogenic and aryl hydrocarbon receptor-mediated bioactivites. A long-standing question has been the relative contribution of domestic (accounting around 55% of inflow) versus industrial sources like the Sappi Pulp and Paper Mill (SPMM; accounting around 45% of inflow) to these bioactivities. During the summer of 2013 SPPM underwent a series of process changes which could potentially influence the contaminant loading into WLSSD. Consequently, a series of effects based monitoring studies on final treated effluent and receiving water were conducted pre-, during, and post SPPM process changes to determine whether these changes in processes markedly affected the bioactivity associated with the effluent. Fathead minnows were exposed to a constant flow of effluent of varying concentrations (100%, 20%, 5%) on site at WLSSD or caged within the St. Louis River receiving waters. Estrogenic activity, as determined using in vitro bioassays, was not markedly altered by the SPPM process changes. Additionally, consistent with previous years, no major impacts on steroid biosynthesis were evident. Hepatic expression of vitellogenin (vtg) mRNA was consistently elevated in males exposed to 100% effluent. This elevation of vtg mRNA was not seen in males exposed to 20% or 5% effluent. The relative abundance of Cytochrome P4501A1 mRNA showed induction in a dose dependent manner between treatment groups for all time points. Analysis of water samples from the different exposure periods yielded the detection of 70 organic contaminants within the final treated effluent. Based on these results, the hypothesis that a change in the pulping process at SPMM would affect contaminant loading from WLSSD into the St. Louis Bay was not supported.