Spider-Mediated Flux of PCBs from Contaminated Sediments to Terrestrial Ecosystems and Potential Risks to Arachnivorous Birds

Citations Over TimeTop 10% of 2009 papers

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 (delta(13)C, delta(15)N) 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 (r(2) = 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 approximately 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.

Related Papers

• → The lateral extent of the subsidy from an upland stream to riparian lycosid spiders(2005)72 cited
• → Effects of reactive nitrogen deposition on terrestrial and aquatic ecosystems(2014)46 cited
• Activities and Ecological Role of Adult Aquatic Insects in the Riparian Zone of Streams(1989)
• → Monitoring of adult aquatic insect activities and ecological role in the riparian zone of streams in the Western Ghats, India(2016)2 cited
• The use of aquatic dipteran insect larvae to monitor heavy metal pollution(2008)