Methodological and Environmental Impacts on Bioaccessibility Estimates Provided by Single-Point Tenax Extractions

• Published in: Archives of environmental contamination and toxicology 2017-05, Vol.72 (4), p.612-621
• Main Authors: Nutile, Samuel A., Harwood, Amanda D., Sinche, Federico L., Huff Hartz, Kara E., Landrum, Peter F., Lydy, Michael J.
• Format: Article
• Language: English
• Subjects: Aging; Bioaccumulation; Bioavailability; Carbon; Carbon content; Chemical contamination; Consistency; Contaminants; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental factors; Environmental Health; Environmental impact; Estimates; Exposure; Geologic Sediments - chemistry; Hinges; Hydrophobicity; Monitoring/Environmental Analysis; Multiple regression analysis; Organic carbon; Organic contaminants; Pollution; Polymers - analysis; Pyrethroids; Sediment pollution; Sediments; Soil Science & Conservation; Water Pollutants, Chemical - analysis
• ISSN: 0090-4341; 1432-0703
• DOI: 10.1007/s00244-017-0395-8

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 ( C rap T 0 ), such that a constant ratio is expected between SPTE and C rap T 0 ( C T / C rap T 0 , 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 C rap T 0 , the utility of the SPTEs as exposure estimates hinges on the consistency of the C T / C rap T 0 ratio. 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 C T / C rap T 0 ratio 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 C 24h / C rap T 0 ratio 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 C 24h / C rap T 0 ratio. Only aging time of the pyrethroids in sediment significantly affected the C 24h / C rap T 0 ratio with a slight decline of −0.0027/d in the C 24h / C rap T 0 ratio, and this decline was considered negligible as a consistent C 24h / C rap T 0 ratio 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.