Surfactants differentially impact p,p'-DDE accumulation by plant and earthworm species.
The effect of four surfactants (Triton X-100, Tween-80, rhamnolipids, cyclodextrin) at 100-1000 mg/L on p,p'-DDE phytoextraction by Cucurbita pepo (zucchini) under field conditions and p,p'-DDE bioaccumulation by earthworm species (Eisenia fetida, Lumbricus terrestris) under laboratory conditions was investigated. Abiotically, surfactants (except cyclodextrin) increased contaminant desorption from soil by 4-fold, with higher concentrations generally promoting greater release. Cyclodextrin had no effect on DDE desorption. DDE concentrations in unamended zucchini roots and stems were 30- and 7.8-fold greater than soil levels, respectively, and 1.6% of the contaminant was extracted from the soil. The surfactant effects were cultivar specific. Triton X-100 increased DDE uptake in "Costata" by 2.6-fold, yielding 5% contaminant phytoextraction. In "Goldrush", DDE accumulation decreased by 69% across all surfactants. Surfactants significantly increased DDE bioaccumulation by earthworms. For E. fetida with all surfactants and L. terrestriswith Triton X-100 and cyclodextrin, DDE accumulation increased 2.5-7.2-fold, paralleling abiotic desorption. However, Tween-80 and rhamnolipids increased DDE accumulation in L. terrestris by 74 and 36 fold, respectively. These dramatic increases in contaminant bioaccumulation do not correlate with the increased availability observed abiotically. Surfactant-mediated increases in contaminant bioavailability are an unexpectedly complex process and clearly present unanticipated concerns over pollutant exposure to nontarget organisms.
White
Jason C
JC
Department of Soil and Water, Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, Connecticut 06504, USA. jason.white@po.state.ct.us
Peters
Richard
R
Kelsey
Jason W
JW
D000818:Animals; D028464:Cucurbita / Q000378:metabolism*; D003633:Dichlorodiphenyl Dichloroethylene / Q000737:chemistry / Q000378:metabolism*; D009835:Oligochaeta / Q000378:metabolism*; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000737:chemistry / Q000378:metabolism; D013501:Surface-Active Agents / Q000737:chemistry*; D013997:Time Factors
D012987:Soil; D012989:Soil Pollutants; D013501:Surface-Active Agents; D003633:Dichlorodiphenyl Dichloroethylene