Library: Letters: Fish & Wildlife

Mr. Tom Alcamo
U. S. Environmental Protection Agency (HSRL-6J)
77 West Jackson Blvd.
Chicago, Illinois 60604

Dear Mr. Alcamo:

This regards the proposed Statement of Work for the Design and Removal Actions at the WinstonThomas Wastewater Treatment Plant in Bloomington, Indiana. The Statement of Work covers the area that is within the metes and bounds of the established site for clean up at Winston-Thomas under the Consent Decree.

This letter has been prepared pursuant to our role as providers of biological and technical assistance to EPA under the Fish and Wildlife Coordination Act (16 USC 661 et seq.) and is consistent with the intent of the National Environmental Policy Act of 1969, the Endangered Species Act of 1973, and the U.S. Fish and Wildlife Service's Mitigation Policy.

We strongly concur with EPA that there needs to be a twelve inch thick soil cover, capable of supporting vegetation, over the abandoned lagoon areas, and that additional grading must be performed to provide adequate drainage and avoid ponding of water. We believe that 12 inches of soil is necessary to ensure elimination of PCB exposure to ecological receptors.

According to the topographic maps of the area, and the engineering evaluation CBS conducted on the tertiary lagoon, it is a fact that the bottom elevations of the tertiary lagoon equal floodplain elevations of Clear Creek. At these same elevations, water is frequently ponding on the West Side of Clear Creek cleanup area. Even if CBS is successful in keeping water from collecting in the lagoon (a dubious proposition if the berms are left standing or if they are taken down and Clear Creek is at flood stage), there will be so little soil left over bedrock in this area that it will undoubtly remain moist in all but the driest months. Under these circumstances, it is quite likely that many "moist soil plants" (i.e. native herbaceous vegetation adapted to germination in hydric soils) such as annual sedge, barnyardgrass, foxtail, fall panicum, crabgrass, and smartweed will proliferate in this area (Laubhan 1992). The seeds of these plants are valuable food sources for a host of wildlife species, including small mammals and passerine birds. These plants in combination with just an inch or two of water would provide excellent waterfowl habitat (Fredrickson and Taylor 1982). Water level management to promote "moist soil units" has been one of the most successful tools used by wildlife managers in the production and management of waterfowl in the Midwest over the last few decades (Fredrickson 1991).

Without any cover, the ecological risks of these exposures to avian receptors will likely approximate the PCB concentrations that we found in American robin utilizing Winston-Thomas in 1992. From a habitat perspective, the robin utilized the least contaminated parts of the Winston-Thomas site (the mowed bluegrass areas). All data collected from these bluegrass areas to date indicate that soil concentrations range from < 1-6 ppm. The robin eggs were roughly 3 times the soil concentration for the habitats utilized. We also expect that bioaccumulation will occur much more readily in moist areas, not altogether unlike the current conditions in the abandoned lagoon area. Some of the highest PCB concentrations ever documented in red-winged blackbird eggs were found in the abandoned lagoon area, and the interesting point of this is that the diet of red-wing blackbirds are at least 50% seeds! It is not unreasonable to expect that we will have red-wing blackbird eggs continue to exceed LD50 levels for PCBs in the tertiary lagoon area if the exposure route is not cut off.

The efficacy of the 6 inches of clean soil cover that has been proposed by CBS for cutting off this exposure route, while better than nothing, will not prevent exposures for long. Small mammals will utilize this area, and their burrowing will open up exposure pathways not only to the individuals burrowing, but to those species that feed on them. Any precipitation, and especially standing water, will speed PCB transport to the surface. Root zones of any vegetation growing here will likely penetrate this cover and during a short period of time render this cap ineffective. More importantly, the re-establishment of this exposure pathway from the contaminated lagoons to wildlife will allow for further concentration and bioaccumulation of PCBs in the Bloomington area wildlife food chain. A full 12 inches of clean cover will significantly reduce the risk of exposure to wildlife, and ensure that the PCB pathway to wildlife remains blocked.

EPA has proposed that ultimately there should be 12 inches of cover at the tertiary lagoon, but it has been willing to consider requiring only 6 inches of cover immediately, while providing for a short delay (one to two years) in implementing the additional clean cover required to allow for a decision on the ultimate use of the site which may alter the cover requirements. While we fear that inadequate clean soil cover poses a continuing risk to wildlife during all but the coldest part of winter, we appreciate the fact that it may be an appropriate exercise of EPA discretion under the NCP to delay implementation of the full twelve inch cover immediately.

If you have any question regarding these comments, or require further information, please contact Dan Sparks on my staff at (812) 334-4261, extension 219.

Sincerely yours,

David C Hudak
Supervisor

Literature Cited

Fredrickson, L.H. and T.S. Taylor. 1982. Management of seasonally flooded impoundments for wildlife. U.S. Department of the Interior, Fish and Wildlife Service, Washington, D.C. Resource Publication 148. 29 pp.

Fredrickson, L.H. 1991. Strategies for water level manipulations in moist-soil systems, in Waterfowl Management Handbook. U.S. Fish and Wildlife. Service, Washington, D.C. Fish and Wildlife Leaflet 13.4.6. 8 pp.

Laubhan, M. 1992. A technique for estimating seed production of common moist-soil plants, in Waterfowl Management Handbook. U.S. Fish and Wildlife Service, Washington, D.C. Fish and Wildlife Leaflet 13.4.5. 8 pp.