EFFECT OF C60 FULLERENES ON THE ACCUMULATION OF WEATHERED p,p′‐DDE BY PLANT AND EARTHWORM SPECIES UNDER SINGLE AND MULTISPECIES CONDITIONS

Abstract

The use of engineered nanomaterials has increased dramatically in recent years, but an understanding of nanomaterial fate and effects in the environment is lacking. In particular, the interaction of nanomaterials with coexisting organic contaminants and the subsequent implications for sensitive biota is almost completely unknown. Here, the effect of C60 fullerenes on the accumulation of weathered dichlorodiphenyldichloroethylene (p,p'-DDE; DDT metabolite) by Cucurbita pepo (pumpkin) and Eisenia fetida (earthworm) was determined under single and multispecies conditions. The plants, in the presence or absence of earthworms, were grown in soil containing weathered DDE (200 ng/g) and 0 or 1,670 mg/kg C60 fullerenes. Plants and earthworms were added either simultaneously or sequentially (earthworms after plants). Neither DDE nor C60 had an impact on survival or biomass of plants and earthworms, although fullerenes significantly decreased (29.6-39.0%) the relative root mass. Under single or multispecies conditions, C60 had little impact on DDE bioaccumulation by either species. The DDE concentrations in non-fullerene-exposed shoots, roots, and earthworms were 181, 7,400, and 8,230 ng/g, respectively. On fullerene exposure, the DDE content was nonsignificantly lower at 163, 7280, and 7540 ng/g, respectively. In the presence of the earthworms, C60 significantly decreased the shoot DDE content (28.6%), but no impact on root concentrations was observed. Root DDE content was unaffected by the presence of fullerenes and decreased by 21.6 to 37.5% during coexposure with earthworms. Earthworm DDE content was decreased by plant presence. Earthworms added to soils after plant harvest accumulated more DDE but were unaffected by the C60 exposure. Additional work is necessary, but these findings suggest that fullerenes may have minimal impact on the bioaccumulation of weathered cocontaminants in soil.