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ASSESSING SOIL ARSENIC BIOAVAILABILITY IN THE LABORATORY MOUSE
Citation:
THOMAS, D. J., M. F. HUGHES, K. HERBIN-DAVIS, AND P. SEALES. ASSESSING SOIL ARSENIC BIOAVAILABILITY IN THE LABORATORY MOUSE. Presented at International Society of Exposure Analysis (ISEA) Annual Meeting, Durham, NC, October 15 - 18, 2007.
Impact/Purpose:
Research presentation.
Description:
Variation among soils in the bioavailability of arsenic can be a critical determinant of the risk posed by exposure to these soils. Although in vitro techniques can provide vital data on aspects of bioavailability of metals and metalloids from soils, these results must be validated in an animal model. A useful animal model provides a measure of bioavailability and allows comparison of bioavailability for different soil matrices. Inbred strains of laboratory mice are potentially good models for development of a bioavailability assay. Laboratory mice are well characterized physiologically and can be manipulated experimentally (e.g, altered dietary components, altered genotype). There is also a large body of data on the absorption, metabolism, disposition, and excretion of inorganic and methylated arsenicals in the mouse which is germane to evaluating the differences and similarities between mouse and human. Initial studies are comparing arsenic bioavailabilities in soils with known arsenic contents with the bioavailability of sodium arsenate. Here, soils (e.g., NIST SRM 2710) or sodium arsenate are added to a standard powdered mouse chow (AIN-93G purified rodent diet) at the one percent (weight/weight) level. Adult female C57BL/6 mice have had free access to this amended chow and tap water for nine days. Urine and feces are collected on a daily basis and food intake is monitored throughout this period. At the end of the nine-day exposure period, mice are euthanized and tissues collected. Data on food consumption and arsenic contents of excreta and selected tissues are used to calculate the bioavailability of arsenic in each soil matrix. Development and refinement of this animal model should provide a convenient and rapid means to assess the absolute and relative bioavailability of arsenic in soils. These data may be of great value in risk assessment. (This abstract does not reflect US EPA policy.)