Abstract

Production of engineered carbon-based nanomaterials (CNM) is rising, with increased risk of release to the environment during production, transportation, use, and disposal. This trend highlights a need to understand potential impacts of CNM on the natural environment. Fullerenes (n-C60) are insoluble in water, and form aggregates that settle quickly, suggesting higher relative vulnerability of aquatic benthic ecosystems. This study aimed to determine eco-toxicity of fullerene and its functionalized derivatives on functionally representative benthic organisms, and evaluate how the potential lethal and sub-lethal effects of fullerene on these organisms indirectly impact benthic ecosystem function, including decomposition, primary productivity and nutrient cycling. We conducted chronic and acute traditional laboratory toxicity tests and a microcosm experiment in natural sediments. Standard toxicity tests indicated that population growth of Lumbriculus variegatus was reduced at 25 to 150 mg C60 kg-1, but C70 and the fullerene derivative C60-PCBM did not affect growth or weight of organisms in artificial sediments at 25 mg kg-1. Survivorship and growth were lower in natural sediments with historic contamination, but there was no measurable additive influence of C60. Photosynthesis by the benthic diatom Nitzschia palea was inhibited in the presence of C60, and at high exposure chlorophyll a increased. L. variegatus had strong effects on benthic ecosystem function, especially metabolism and nitrogen cycling, but C60 ≤ 30 mg kg-1 sediment did not influence the role of L. variegatus in driving benthic processes. These observations suggest that at moderate to high concentrations under ideal conditions, C60 may directly impact benthic organisms. However, under natural conditions with low to moderate concentrations, C60 does not indirectly impact the ecosystem processes maintained by such organisms. These results are a step further towards a better understanding of potential impacts of CNMs on aquatic ecosystems, and can aid in the development of regulatory policies.

Publication Date

6-25-2018

Document Type

Thesis

Student Type

Graduate

Degree Name

Environmental Science (MS)

Department, Program, or Center

Thomas H. Gosnell School of Life Sciences (COS)

Advisor

Anna Christina Tyler

Advisor/Committee Member

Callie Babbitt

Advisor/Committee Member

Corey Ptak

Campus

RIT – Main Campus

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