Bioaccumulation of polychlorinated dibenzo-p-dioxins/dibenzofurans in E. fetida from floodplain soils and the effect of activated carbon amendment.
Laboratory studies were conducted to evaluate the bioaccumulation of aged polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in soil near the base of the terrestrial food chain using earthworms (E. fetida) as a model organism. This research also assessed the effect of activated carbon (AC) addition to soil on PCDD/F bioaccumulation in earthworms and passive uptake in polyoxymethylene (POM) samplers. Two soils taken from a wetland and a levee along the Tittabawassee River floodplain downstream of Midland, MI were used in this study. In the untreated soils, biota sediment accumulation factors (BSAFs) ranged from 0.17 for 2,3,7,8-TCDD to 0.02 for some of the higher chlorinated congeners, which were substantially lower than would be predicted using a conventional equilibrium partitioning model. The addition of AC to the floodplain soils generally reduced the BSAF values to lower than 0.02. Amendment of the wetland soil (having a high organic content) with 2% and 5% AC resulted in a 78 and 91% reduction of toxicity equivalent (TEQ) in earthworms, respectively. More strikingly, amendment of the natural levee soil (having a low organic content) with 2% and 5% AC showed >99% reduction of TEQ in earthworms. Also, freely dissolved aqueous concentrations of PCDD/Fs in soil slurries, as measured by equilibrium passive samplers, decreased up to 99% with AC treatment. Results of this study indicate that bioaccumulation of PCDD/Fs in earthworms from historically impacted floodplain soils is low and can be further reduced by amending with a strong sorbent.
Fagervold
Sonja K
SK
Department of Civil and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland 21250, USA.
Chai
Yunzhou
Y
Davis
John W
JW
Wilken
Michael
M
Cornelissen
Gerard
G
Ghosh
Upal
U
D000818:Animals; D001572:Benzofurans / Q000737:chemistry / Q000378:metabolism*; D002244:Carbon / Q000494:pharmacology*; D000072338:Dibenzofurans, Polychlorinated; D020387:Food Chain; D009835:Oligochaeta / Q000187:drug effects / Q000378:metabolism*; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000378:metabolism*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism
D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D000072317:Polychlorinated Dibenzodioxins; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D014867:Water; D002244:Carbon