Polybrominated Diphenyl Ether Accumulation in an Agricultural Soil Ecosystem Receiving Wastewater Sludge Amendments

Few studies have addressed bioaccumulation of organic pollutants associated with land-application of biosolids. We thus examined PBDE burdens within a soil ecosystem receiving long-term sludge amendments and a reference soil ecosystem receiving only manure inputs. No PBDEs were detected in reference site samples, but sludge-amended soils contained 17 600 +/- 2330 mu g/kg Sigma 3-7PBDE (total organic carbon (TOG) basis). Sigma 3-7PBDE burdens were highest in soil invertebrates with the greatest contact with sludge-amended soil (e.g., Sigma 3-7PBDE of 10 300 +/- 2670 and 3000 +/- 200 mu g/kg lipid for earthworms and detritivorous woodlice, respectively). PBDEs were below quantitation limits in vegetation from the sludge-amended site. Surprisingly, we measured quantifiable PBDE burdens in only a single sample of predaceous ground spiders from the sludge-amended site. BDE-209 burdens in sludge-amended soil and earthworms were 7500 +/- 2800 mu g/kg TOG and 6500 +/- 4100 mu g/kg lipid, respectively. BDE 209 was detected in fewer taxa, but the burden in a detritivorous millipede composite was high (86 000 mu g/kg lipid). PBDE congener patterns differed among species, with worms and ground beetles exhibiting Penta-BDE-like patterns. Penta-BDE biota-soil accumulation factors (BSAFs) ranged from 0.006 to 1.2, while BDE-209 BSAFs ranged from 0.07 to 10.5. delta C-13 and delta N-15 isotope signatures were poorly correlated with PBDE burdens, but sludge-amended samples were significantly delta N-15 enriched.