The Air Force is drafting a proposed plan evaluating alternatives for cleaning up contaminated sediment in creeks, vernal pools, and tailings (materials dredged out of the creeks in 1997 as a flood control measure) on the former McClellan Air Force Base. Chemicals used at McClellan from 1936-2001
- when the base was active - have contributed to soil contamination. The proposed plan will be available for public comment this summer.
Two main creeks flow through the central part of the former base: Magpie Creek and Don Julio Creek. In the western portion of the former base, the creeks enter a 225-acre natural habitat area for aquatic and wetland plants and animals. Canada geese, red-winged blackbirds, mallards, green herons, and many other birds nest or winter in the area. River otters and beavers inhabit the creeks, along with a variety of fish, crayfish, western pond turtles and other aquatic life.
Of particular concern are rare and endangered species which might live in or around creeks at the former base. Vernal pool fairy shrimp, a federally threatened species, have been found in the vernal pools that are scattered throughout the floodplain of the creeks. The creeks and adjacent habitats may also support the Giant Garter Snake and the Valley Elderberry Longhorn Beetle, two other federally listed species. Neither of these has been sighted at McClellan.
For purposes of evaluation, the creeks at McClellan were split into different sections, because each section of creek contains different levels of contamination and may or may not support significant wildlife habitat. Contaminants of concern included PCBs (polychlorinated biphenyls), dioxins/furans, PAHs (polycyclic aromatic hydrocarbons), Total DDT, bis(2-ethylhexyl)phthalate, cadmium and silver.
Cleanup actions must comply with CERCLA (the Comprehensive Environmental Response, Compensation and Liability Act) and strike the most appropriate balance between human health concerns, ecological risk mitigation, and impacts on habitat quality. Remedial action might include a variety of things, such as leaving low-level contamination in place and monitoring it over time or removing contaminated sediments.
Cleanup goals include: (1) reducing the current and future risk to ecological receptors (plants and animals) from exposure to contaminants in sediment to an acceptable level; and (2) reducing the potential risk to human health from consumption of crayfish or other biota from the creeks. According to the study, human health could be adversely affected if a person consumed regular meals of crayfish, fish or other organisms from the creeks throughout his or her lifetime (eight ounces, three times per month over a period of 30 years.) This potential risk would be addressed by imposing fishing restrictions.
The Air Force will be issuing the proposed plan this summer. The plan must be approved by regulators, and public comment is evaluated as part of the approval process. A 30-day public comment period will follow the plan’s release. For a copy of the proposed plan, notification of the timing of the public comment period, or a presentation to your group about the proposed plan, please contact Mary Hall at McClellan Community Relations, (916) 643-0830, extension 232; or by email at mary.hall.5.ctr@us.af.mil