Fox River sediment study to produce cleanup strategies After years of study, a coalition of Wisconsin paper industries, municipalities, and the state Department of Natural Resources is expected to announce later this year several scenarios to clean up some of the most contaminated river sediments in the United States. The Fox River Coalition's plans to clean up Wisconsin's polychlorinated biphenyl (PCB)tainted Fox River will be closely watched by environmentalists and federal agencies to see if the voluntary group can convert ground-breaking science into action. The highly contaminated sediments in the lower Fox River are also some of the best studied. Funded by EPA and the state, the Green Bay/Fox River Mass Balance Study began in 1988 and was designed to inform cleanup strategies by modeling mass balances for an entire river system. More than 50 federal, state, and academic researchers were involved. All point sources, sediments, and tributary inputs were measured for PCB congeners. Atmospheric inputs and losses were also measured, as were water column concentrations. "The modelers were involved from the beginning in deciding what data to collect, so we had good controls on all important parameters," said modeler John Connelly of HydroQual consultants in Mahwah, NJ. "That was an unusual situation." Results of the mass balance study, published in the Journal of Great Lakes Research in 1994, show that the single most important source of PCBs for Green Bay is contaminated Fox River sediments and that this contamination was caused mainly by past discharges from the area's paper mills. The Fox River valley has the highest concentration of paper mills in the world, and between 1960 and 1970 more than 150,000 kg of PCBs went into the river. Although PCB concentrations are gradually decreasing, the modeling predicts that without
cleanup action 100 years will pass before contamination decreases enough to end Green Bay fish consumption advisories. The Green Bay study also produced significant modeling advances, including a better way to characterize sediment flow, according to PCB modeler Mark Velleux, formerly with EPA and now with Wisconsin Department of Natural Resources. "For sediment transport models, settling and resuspension velocities are some of the most difficult variables to assign. But we found a way to treat these as functions of river flow, the principal independent variable. This advance, the Inplace Pollutant Export Model or IPX, is already being used on other rivers." The Fox River approach is now being expanded to the entire lake through EPA's Lake Michigan Mass Balance Study with the goal of producing a model to predict contaminant concentration in top predators for Lake Michigan. According to Glen Warren of the EPA Great Lakes National Program Office, sampling began in April 1994 and will be completed in October, with results expected in 1997. Interactive models produced by the Fox River mass balance study are being used by the Coalition to prioritize sediment bodies for cleanup. The Coalition is preparing several whole-river cleanup scenarios for public consideration, according to coordinator Jo Mercurio.
Modeling is the best way to prioritize cleanups, says Joe DePinto from the State University of New York at Buffalo. "Just measuring sediments does not give enough information to decide what to clean up. Modeling accounts for contaminant concentrations and for contaminant mobility. That's what you need." Environmental groups complain of delay but say they are "cautiously optimistic" about the Coalition's plans. "Funding is our main concern," said Lake Michigan Federation representative Dan Burke. "Until now the coalition has secured tens of thousands of dollars when it's been needed. But this cleanup is going to cost tens of millions. What happens if companies back out after so much public money has been spent to help fund the ground work?" While the Coalition pursues a voluntary path, Region 3 of the Department of Fish and Wildlife is moving ahead with the only legal mechanism available in this case: a Natural Resources Damage Assessment. Fish and Wildlife has identified five potentially responsible parties and is preparing an assessment plan, the first step in a process that leads to a restoration plan and claims filed against potentially responsible parties (PRPs) for damages. The department now is negotiating with the PRPs, according to T. J. Miller, Region 3 Chief of Division of Environmental Contamination. —REBECCA RENNER
VOL. 29, NO. 9, 1995 /ENVIRONMENTAL SCIENCE & TECHNOLOGY • 4 0 1 A
