Assessing Biological Interactions and Potential Impacts of Emerging Carbonaceous Materials to Terrestrial Organisms

[摘要] This research addresses the potential ecotoxicity of two emerging carbonaceousmaterials: C 60 and biochar. The use of these materials is rapidly increasing, as wellas their potential for widespread applications. Thus, information about unintendedconsequences associated the widespread use, incidental or accidental release, anddisposal of these emerging materials is needed. The environmental impacts of C 60 , itsstable water suspension (nC 60 ), and biochar are assessed here using bacteria andearthworms as model receptors.The antibacterial activity of nC 60 can be mitigated by the presence of natural organicmatter as a soil constituent or dissolved in the water column. Sorption to soil mightdecrease the bioavailability of nC 60 and thus its toxicity to bacteria. Aqueousorganic matter also may mitigate nC 60 toxicity. Pristine C 60 showed toxicity to theearthworm's reproduction and was rapidly bioaccumulated by earthworms, although to alower extent than smaller phenanthrene molecules that are more hydrophobic; thus, thelarge molecular size of C 60 hinders its bioaccumulation. Less bioaccumulation occurredat higher C 60 concentration in soil, which is counterintuitive and reflects thathigher C 60 concentrations that exceed the soil sorption capacity exist as largerprecipitates that are less bioavailable. Earthworms avoided soils amended with highconcentrations of dry biochar, and experienced significant weight loss after 28-dayexposure. The avoidance response was likely to avert desiccation rather than to avoidpotential toxicants (i.e., PAHs formed during biochar production by pyrolysis) ornutrient scarcity. By wetting the biochar to field capacity before exposing the worms,this adverse effect can be completely mitigated. Overall, this research provides afoundation for ecotoxicity assessment associated with exposure to C 60 or biochar, andestablishes a method by which other emerging materials can be evaluated for theirpotential environmental impacts.

[发布机构] Rice University

[效力级别] health