PARENT SESSION
WP4 - Exposure and Analysis of Brominated Flame Retardants (BFRs)
Chair: Priest, Benjamin1, 1 Cambridge Isotope Laboratories, Andover, MA
2:10 PM to 5:30 PM - Wednesday, 20 November 2002
Room Ballroom F
(603) Bioavailability of polybrominated diphenyl ethers in biosolids and sediment to Lumbriculus variegatus.
Ciparis, Serena*,1, Hale, Robert1, La Guardia, Mark, 1 Virginia Institute of Marine Science, Gloucester Point, VA, USA
ABSTRACT- Polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants (POPs) currently used as flame retardant polymer additives. They appear to have a global distribution akin to the comparatively well-studied organochlorine POPs. High concentrations of PBDEs have been previously reported in US fish. High levels have also been observed in US biosolids, i.e. treated sewage sludge applied to agricultural, public and reclaimed lands as a fertilizer and soil conditioner. This practice provides an avenue for subsequent redistribution of PBDEs to surface waters. However, little is known about the bioavailability of biosolid- or sediment-associated PBDEs to aquatic organisms. In this study, freshwater oligochaetes, Lumbriculus variegatus, were exposed to composted biosolids (1500 ng/g total PBDEs) and artificial sediment spiked with a commercial Penta-BDE formulation and BDE 209 (1700 ng/g total PBDEs), the congener that constitutes the bulk of the Deca-BDE commercial product. Uptake was studied over a 28-day exposure period and elimination over 21 days. PBDEs were bioavailable to L. variegatus from both spiked sediment and biosolids. Uptake of PBDE congeners was 5-10 times greater from spiked sediment than from biosolids. For tetra- through hexa-brominated congeners, apparent steady-state concentrations were achieved within the 28-day exposure period. Of the seven PBDE congeners studied, BDE 47 and BDE 99 were the most prevalent in the substrates and oligochaetes. In the worms BDE 47 accumulated to a greater degree than BDE 99. BDE 47 also dominates in reports of burdens in wildlife. By the end of the 21-day depuration period, oligochaetes from both substrates had eliminated the majority of their 28-day body burden for all PBDE congeners. BDE 47 was eliminated more slowly than BDE 99. Uptake of PBDE congeners from biosolids and sediments by benthic organisms provides an pathway for their transfer to higher trophic levels. The reduced bioavailability of PBDEs in biosolids compared to spiked sediment has important implications for future studies.
Key words: polybrominated diphenyl ethers, biosolids, bioavailability, oligochaetes