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Toxicity of sediment oiled with diluted bitumens to freshwater and estuarine amphipods
Citation:
Barron, M., E. Moso, R. Conmy, P. Meyer, AND D. Sundaravadivelu. Toxicity of sediment oiled with diluted bitumens to freshwater and estuarine amphipods. MARINE POLLUTION BULLETIN. Elsevier Science Ltd, New York, NY, 163:7, (2021). https://doi.org/10.1016/j.marpolbul.2020.111941
Impact/Purpose:
This manuscript describes the results of laboratory-based exposure studies to examine the toxicity of sediments oiled with diluted bitumens (dilbits) to two benthic invertebrate species. The ecotoxicological implications of dilbit toxicity are of concern because the increased risk of exposure of aquatic environments to catastrophic spills as the transport these petroleum products increases in North America. Little is known about the fate and effects of these unconventional oils that can sink and associate with sediment. This paper includes new information to improve our understanding of the effects of dilbits on benthic organisms. We compared toxicity-based benchmarks derived from this study to dilbit concentrations measured in sediments in the environment after spill events, and conclude that dilbit spills in aquatic habitats may pose substantial risks to freshwater and estuarine benthic organisms. This information will assist resource managers to assess future risk and impacts from dilbit spills in freshwater and estuarine environments.
Description:
To address knowledge gaps and the lack of benchmarks on the toxicity of dilbit oiled sediments, weathered Cold Lake Blend (CLB) and Western Canadian Select (WCS) were assessed in 10-day sediment tests with the amphipods Hyalella azteca and Leptocheirus plumulosus. Lowest observed effect concentrations (LOECs) and 20% effect levels (EC20s) were determined for wet weight sediment concentrations of TPH and total PAHs normalized to 1% organic carbon. LOECs and EC20s for TPH ranged from 216 to 1165 mg/kg sediment in H. azteca, and from 64 to 75 mg/kg sediment in L. plumulosus. Dilbit LOECs and EC20s for total PAHs ranged from 2.9 to 11.8 mg/kg sediment in H. azteca, and from 0.75 to 0.87 mg/kg in L. plumulosus. Comparison of toxicity-based benchmarks derived from the current study to sediment concentrations from past spills indicate that dilbit spills in aquatic habitats may pose substantial risks to freshwater and estuarine benthic organisms.
URLs/Downloads:
DOI: Toxicity of sediment oiled with diluted bitumens to freshwater and estuarine amphipods