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Spider-mediated flux of PCBs from contaminated sediments to terrestrial ecosystems and potential risks to arachnivorous birds

Environmental Science and Technology

By:
, , ,
DOI: 10.1021/es9023139

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Abstract

We investigated aquatic insect utilization and PCB exposure in riparian spiders at the Lake Hartwell Superfund site (Clemson, SC). We sampled sediments, adult chironomids, terrestrial insects, riparian spiders (Tetragnathidae, Araneidae, and Mecynogea lemniscata), and upland spiders (Araneidae) along a sediment contamination gradient. Stable isotopes (?13C, ? 15N) indicated that riparian spiders primarily consumed aquatic insects whereas upland spiders consumed terrestrial insects. PCBs in chironomids (mean 1240 ng/g among sites) were 2 orders of magnitude higher than terrestrial insects (15.2 ng/g), similar to differences between riparian (820?2012 ng/g) and upland spiders (30 ng/g). Riparian spider PCBs were positively correlated with sediment concentrations for all taxa (r2 = 0.44?0.87). We calculated spider-based wildlife values (WVs, the minimum spider PCB concentrations causing physiologically significant doses in consumers) to assess exposure risks for arachnivorous birds. Spider concentrations exceeded WVs for most birds at heavily contaminated sites and were ?14-fold higher for the most sensitive species (chickadee nestlings, Poecile spp.). Spiders are abundant and ubiquitous in riparian habitats, where they depend on aquatic insect prey. These traits, along with the high degree of spatial correlation between spider and sediment concentrations we observed, suggest that they are model indicator species for monitoring contaminated sediment sites and assessing risks associated with contaminant flux into terrestrial ecosystems. ?? This article not subject to U.S. Copyright. Published 2009 by the American Chemical Society.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Spider-mediated flux of PCBs from contaminated sediments to terrestrial ecosystems and potential risks to arachnivorous birds
Series title:
Environmental Science and Technology
DOI:
10.1021/es9023139
Volume
44
Issue:
8
Year Published:
2010
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
2849
Last page:
2856
Number of Pages:
8