R7 AM Soil Ecotoxicology and Risk Assessment
Thursday, 17 November 2005: 8:00 AM - 11:40 AM in 327-329

(SAM-1117-754133) Evaluation of Ecological Risks at the Old Skeet Range, Naval Weapons Station Seal Beach, California.

Sample, B¹, Arenal, C¹, ¹ CH2M HILL, Sacramento, CA, USA

ABSTRACT- : Screening ecological risk assessments (ERAs) for the Old Skeet Range at Naval Weapons Station Seal Beach, California, identified potential risks from lead and antimony. Portions of the site lie within a National Wildlife Refuge and provide habitat for two federal T&E species (light-footed clapper rail and Beldings savannah sparrow). A baseline ERA was performed. Given screening results and up to 154000 mg/kg lead in soil, ecological risks were assumed. ERA focused on spatial delineation of risks and identification of potential cleanup levels. Assessment endpoints included plants, invertebrates, aquatic birds, terrestrial birds and mammals, and T&E species. Data collected included co-located soil or sediment and biota samples, bird and mammal liver tissue, and soil and sediment for bioaccessibility analyses. Site-specific plant and sediment invertebrate bioassays were also conducted. Concentrations of lead and antimony produced dietary estimates that exceeded toxicity thresholds for all bird and mammal receptors in some samples. Measured lead in livers of birds and mammals exceeded background but not effect thresholds. Estimated lead in livers of birds and mammals suggest risk at some sampling locations. Lead as shot exists in concentrations that present risks to birds. Toxicity attributable to lead and antimony was observed in the site-specific sediment bioassays. Results of plant bioassays were confounded by salt phytotoxicity. Lead and antimony exceeded literature-based plant and invertebrate toxicity values in some samples. Point-by-point risk results were used to develop two remediation footprints, one based on the most sensitive receptor (Beldings savannah sparrow) and the other based on the next most sensitive set of receptors. Based on several considerations (e.g., potential for significant habitat disruption and destruction), comparative analyses of the effects and benefits of different remedial alternatives were recommended. In particular, an evaluation weighing the relative benefits of remediation strategies versus damage to sensitive habitat is warranted.

Key words: Skeet Range, Lead Shot, Ecological Risk Assessment, Endangered Species