title: Methodological and Environmental Impacts on Bioaccessibility Estimates Provided by Single-Point Tenax Extractions.
abstract: Single-point Tenax extractions (SPTEs) of hydrophobic organic contaminants provide estimates of bioaccessibility through consistent measures of the chemical concentration initially in the rapidly desorbing fraction in sediment (CrapT0), such that a constant ratio is expected between SPTE and CrapT0(CT/CrapT0, where T is the duration of the SPTE). As environmental factors (i.e., aging time and organic carbon content) and contaminant hydrophobicity can affect the CrapT0, the utility of the SPTEs as exposure estimates hinges on the consistency of the CT/CrapT0ratio. Individually these factors have little impact on the ability of SPTEs to represent bioaccumulation, but the effect of these factors in combination, as well as SPTE methodological variation on the CT/CrapT0ratio is poorly understood. The current study evaluated how environmental and methodological variation-expressed as varying Tenax to organic carbon mass (Tenax:OC) ratios-impacts the C24h/CrapT0ratio of pyrethroids in laboratory-spiked sediments. A multiple regression analysis was used to examine the impact of organic carbon, pyrethroid hydrophobicity, Tenax mass, and aging time on the C24h/CrapT0ratio. Only aging time of the pyrethroids in sediment significantly affected the C24h/CrapT0ratio with a slight decline of -0.0027/d in the C24h/CrapT0ratio, and this decline was considered negligible as a consistent C24h/CrapT0ratio of 1.46 ± 0.03 was observed across all experimental treatments. This result further demonstrates the consistency of SPTEs to estimate bioaccessibility of hydrophobic contaminants in sediment and subsequent exposure.
authors.affiliation: Center for Fisheries, Aquaculture and Aquatic Sciences and Department of Zoology, Southern Illinois University, Life Science II Rm 251, 1125 Lincoln Drive, Carbondale, IL, 62901, USA.
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Nutile
authors.affiliation: Biology and Environmental Studies, Alma College, Alma, MI, 48801, USA.
authors.forename: Amanda D
authors.initials: AD
authors.lastname: Harwood
authors.affiliation: Center for Fisheries, Aquaculture and Aquatic Sciences and Department of Zoology, Southern Illinois University, Life Science II Rm 251, 1125 Lincoln Drive, Carbondale, IL, 62901, USA.
authors.forename: Federico L
authors.initials: FL
authors.lastname: Sinche
authors.affiliation: Center for Fisheries, Aquaculture and Aquatic Sciences and Department of Zoology, Southern Illinois University, Life Science II Rm 251, 1125 Lincoln Drive, Carbondale, IL, 62901, USA.
authors.forename: Kara E
authors.initials: KE
authors.lastname: Huff Hartz
authors.affiliation: Center for Fisheries, Aquaculture and Aquatic Sciences and Department of Zoology, Southern Illinois University, Life Science II Rm 251, 1125 Lincoln Drive, Carbondale, IL, 62901, USA.
authors.forename: Peter F
authors.initials: PF
authors.lastname: Landrum
authors.affiliation: Center for Fisheries, Aquaculture and Aquatic Sciences and Department of Zoology, Southern Illinois University, Life Science II Rm 251, 1125 Lincoln Drive, Carbondale, IL, 62901, USA. mlydy@siu.edu.
authors.forename: Michael J
authors.identifier: http://orcid.org/0000-0003-1633-2109
authors.initials: MJ
authors.lastname: Lydy
mesh_terms: D004777:Environment; D019015:Geologic Sediments / Q000737:chemistry; D011108:Polymers / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D011108:Polymers; D014874:Water Pollutants, Chemical; C010514:tenax