title: Addition of contaminant bioavailability and species susceptibility to a sediment toxicity assessment: application in an urban stream in China.
abstract: Sediments collected from an urban creek in China exhibited high acute toxicity to Hyalella azteca with 81.3% of sediments being toxic. A toxic unit (TU) estimation demonstrated that the pyrethroid, cypermethrin, was the major contributor to toxicity. The traditional TU approach, however, overestimated the toxicity. Reduced bioavailability of sediment-associated cypermethrin due to sequestration explained the overestimation. Additionally, antagonism among multiple contaminants and species susceptibility to various contaminants also contributed to the unexpectedly low toxicity to H. azteca. Bioavailable TUs derived from the bioavailability-based approaches, Tenax extraction and matrix-solid phase microextraction (matrix-SPME), showed better correlations with the noted toxicity compared to traditional TUs. As the first successful attempt to use matrix-SPME for estimating toxicity caused by emerging insecticides in field sediment, the present study found freely dissolved cypermethrin concentrations significantly improved the prediction of sediment toxicity to H. azteca compared to organic carbon normalized and Tenax extractable concentrations.
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors.forename: Huizhen
authors.initials: H
authors.lastname: Li
authors.forename: Baoquan
authors.initials: B
authors.lastname: Sun
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lydy
authors.forename: Jing
authors.initials: J
authors.lastname: You
mesh_terms: D033304:Amphipoda; D000818:Animals; D002681:China; D002947:Cities; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry*; D018570:Risk Assessment; D045483:Rivers / Q000737:chemistry*; D013045:Species Specificity; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical