title: Assessment and improvement of biotransfer models to cow's milk and beef used in exposure assessment tools for organic pollutants.
abstract: The aim of this study was to assess and improve the accuracy of biotransfer models for the organic pollutants (PCBs, PCDD/Fs, PBDEs, PFCAs, and pesticides) into cow's milk and beef used in human exposure assessment. Metabolic rate in cattle is known as a key parameter for this biotransfer, however few experimental data and no simulation methods are currently available. In this research, metabolic rate was estimated using existing QSAR biodegradation models of microorganisms (BioWIN) and fish (EPI-HL and IFS-HL). This simulated metabolic rate was then incorporated into the mechanistic cattle biotransfer models (RAIDAR, ACC-HUMAN, OMEGA, and CKow). The goodness of fit tests showed that RAIDAR, ACC-HUMAN, OMEGA model performances were significantly improved using either of the QSARs when comparing the new model outputs to observed data. The CKow model is the only one that separates the processes in the gut and liver. This model showed the lowest residual error of all the models tested when the BioWIN model was used to represent the ruminant metabolic process in the gut and the two fish QSARs were used to represent the metabolic process in the liver. Our testing included EUSES and CalTOX which are KOW-regression models that are widely used in regulatory assessment. New regressions based on the simulated rate of the two metabolic processes are also proposed as an alternative to KOW-regression models for a screening risk assessment. The modified CKow model is more physiologically realistic, but has equivalent usability to existing KOW-regression models for estimating cattle biotransfer of organic pollutants.
authors.affiliation: Department of Geography and Environmental Science, School of Archaeology, Geography and Environmental Science, University of Reading, Reading RG6 6DW, United Kingdom.
authors.forename: Koki
authors.initials: K
authors.lastname: Takaki
authors.affiliation: Department of Geography and Environmental Science, School of Archaeology, Geography and Environmental Science, University of Reading, Reading RG6 6DW, United Kingdom.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Wade
authors.affiliation: Department of Geography and Environmental Science, School of Archaeology, Geography and Environmental Science, University of Reading, Reading RG6 6DW, United Kingdom. Electronic address: c.d.collins@reading.ac.uk.
authors.forename: Chris D
authors.initials: CD
authors.lastname: Collins
mesh_terms: D000818:Animals; D004781:Environmental Exposure / Q000032:analysis*; D004785:Environmental Pollutants / Q000737:chemistry / Q000378:metabolism*; D005399:Fishes / Q000378:metabolism; D006801:Humans; D008892:Milk / Q000378:metabolism*; D008954:Models, Biological; D009930:Organic Chemicals / Q000737:chemistry / Q000378:metabolism*; D021281:Quantitative Structure-Activity Relationship; D000069466:Red Meat; D018570:Risk Assessment
chemical_list: D004785:Environmental Pollutants; D009930:Organic Chemicals
keywords: Cattle biotransfer model; Exposure assessment tools; Model intercomparison; Organic pollutants; Quantitative structure–activity relationship