title: Sediment nickel bioavailability and toxicity to estuarine crustaceans of contrasting bioturbative behaviors--an evaluation of the SEM-AVS paradigm.
abstract: Robust sediment quality criteria require chemistry and toxicity data predictive of concentrations where population/community response should occur under known geochemical conditions. Understanding kinetic and geochemical effects on toxicant bioavailability is key, and these are influenced by infaunal sediment bioturbation. This study used fine-scale sediment and porewater measurement of contrasting infaunal effects on carbon-normalized SEM-AVS to evaluate safe or potentially toxic nickel concentrations in a high-binding Spartina saltmarsh sediment (4%TOC; 35-45 μmol-S2-·g(-1)). Two crustaceans producing sharply contrasting bioturbation--the copepod Amphiascus tenuiremis and amphipod Leptocheirus plumulosus--were cultured in oxic to anoxic sediments with SEM[Ni]-AVS, TOC, porewater [Ni], and porewater DOC measured weekly. From 180 to 750 μg-Ni·g(-1) sediment, amphipod bioturbation reduced [AVS] and enhanced porewater [Ni]. Significant amphipod uptake, mortality, and growth-depression occurred at the higher sediment [Ni] even when [SEM-AVS]/foc suggested acceptable risk. Less bioturbative copepods produced higher AVS and porewater DOC but exhibited net population growth despite porewater [Ni] 1.3-1.7× their aqueous [Ni] LOEC. Copepod aqueous tests with/without dissolved organic matter showed significant aqueous DOC protection, which suggests porewater DOC attenuates sediment Ni toxicity. The SEM[Ni]-AVS relationship was predictive of acceptable risk for copepods at the important population-growth level.
authors.affiliation: Department of Environmental Health Sciences, Norman J. Arnold School of Public Health, University of South Carolina , Columbia, South Carolina 29208, United States.
authors.forename: G Thomas
authors.initials: GT
authors.lastname: Chandler
authors.forename: Christian E
authors.initials: CE
authors.lastname: Schlekat
authors.forename: Emily R
authors.initials: ER
authors.lastname: Garman
authors.forename: Lijian
authors.initials: L
authors.lastname: He
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Washburn
authors.forename: Emily R
authors.initials: ER
authors.lastname: Stewart
authors.forename: John L
authors.initials: JL
authors.lastname: Ferry
mesh_terms: D033304:Amphipoda / Q000187:drug effects; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001681:Biological Assay; D001682:Biological Availability; D002244:Carbon / Q000494:pharmacology; D033342:Copepoda / Q000187:drug effects; D003445:Crustacea / Q000187:drug effects*; D063366:Estuaries; D019015:Geologic Sediments / Q000737:chemistry*; D007814:Larva / Q000187:drug effects; D008670:Metals / Q000302:isolation & purification*; D009532:Nickel / Q000633:toxicity*; D016062:Porosity; D013440:Sulfides / Q000302:isolation & purification*; D014835:Volatilization; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D008670:Metals; D013440:Sulfides; D014874:Water Pollutants, Chemical; D002244:Carbon; D009532:Nickel