Bioavailability and toxicological assessment of lead-contaminated sediments in an urban riverine marsh

Abstract

The La Crosse, Wisconsin Gun Club maintained a trapshooting range at the site of the La Crosse River Marsh (LRM) for three decades (1929-1963) resulting in lead (Pb)- contaminated sediments. Because Pb causes physical deformities, behavioral changes, and reproductive dysfunctions in humans and wildlife, it is essential that the potential Pb bioavailability and risk of these contaminated sediments to wildlife and humans be determined. Several fish species were sampled from a variety of trophic levels at reference sites (0-200 mg/kg) and within areas that contained low (400-1000 mg/kg), medium (2,000 - 4,000 mg/kg) and high (4,000 - 8,000 mg/kg) Pb-contaminated surface sediments. Pb from contaminated sites was bioavailable for fish with no correlations between Pb levels among fish and Pb levels from contaminated surface sediments. Also, Pb levels among fish did not differ between species. Additional, laboratory toxicity assays were conducted with zebrafish larvae to determine whether Pb-contaminated surface sediments from the LRM pose toxicological risk to fish. Lab results indicate exposure to LRM surface sediments induced mortality, impaired development, and caused neurotoxicity; however, toxicity was minimal with no distinct dose-response curve. Further research would help determine if remediation is needed or the LRM needs to be listed as a contaminated waters.