title: Oral relative bioavailability of Dichlorodiphenyltrichloroethane (DDT) in contaminated soil and its prediction using in vitro strategies for exposure refinement.
abstract: In this study, the bioavailability of DDTr (sum of DDT, DDD and DDE isomers) in pesticide-contaminated soil was assessed using an in vivo mouse model. DDTr relative bioavailability (RBA) ranged from 18.7±0.9 (As35) to 60.8±7.8% (As36) indicating that a significant portion of soil-bound DDTr was not available for absorption following ingestion. When DDTr bioaccessibility was assessed using the organic Physiologically Based Extraction Test (org-PBET), the inclusion of a sorption sink (silicone cord) enhanced DDTr desorption by up to 20-fold (1.6-3.8% versus 18.9-56.3%) compared to DDTr partitioning into gastrointestinal fluid alone. Enhanced desorption occurred as a result of the silicone cord acting as a reservoir for solubilized DDTr to partition into, thereby creating a flux for further desorption until equilibrium was achieved. When the relationship between in vivo and in vitro data was assessed, a strong correlation was observed between the mouse bioassay and the org-PBET+silicone cord (slope=0.94, y-intercept=3.5, r(2)=0.72) suggesting that the in vitro approach may provide a robust surrogate measure for the prediction of DDTr RBA in contaminated soil.
authors.affiliation: Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia. Electronic address: Albert.Juhasz@unisa.edu.au.
authors.forename: Albert L
authors.initials: AL
authors.lastname: Juhasz
authors.affiliation: South Australian Health and Medical Research Institute, Gilles Plains, SA 5086, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Herde
authors.affiliation: Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
authors.forename: Euan
authors.initials: E
authors.lastname: Smith
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000284:Administration, Oral; D000327:Adsorption; D000818:Animals; D001682:Biological Availability; D003634:DDT / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics; D005260:Female; D007306:Insecticides / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008807:Mice, Inbred BALB C; D012828:Silicones / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics
chemical_list: D007306:Insecticides; D012828:Silicones; D012989:Soil Pollutants; D003634:DDT
keywords: Bioaccessibility; Correlation; DDT; Relative bioavailability; Sorption Sink