title: Modeling zinc regulation in small mammals.
abstract: Due to large zinc discharges into the global environment, both terrestrial and aquatic environments have been polluted with zinc. The embanked floodplains of the lower Rhine River in the Netherlands contain large amounts of heavy metals, including zinc. These large amounts of heavy metals may pose risks to flora and fauna by accumulation in food webs, and risk assessment may be required. However, toxicokinetic models for zinc metabolism in mammalian wildlife species are currently lacking. The present study describes the development of a zinc kinetics model that predicts internal zinc concentrations in small mammals by modeling zinc absorption and excretion dependent on the dietary zinc intake using adapted Michaelis-Menten equations. The equations were parameterized based on experimental data reported in the scientific literature. Within the dietary zinc range of 3 to 104 mg/kg dry weight, the model predicts internal zinc concentrations and shows that the internal zinc is regulated within this range. Outside this range, the model could not be calibrated due to a lack of data. Validation of the model with four small mammal species living in an embanked floodplain along a distributary of the Rhine River illustrated that the model predicts internal zinc concentrations differing up to a factor of 1.6 (Common shrew) to 1.7 (Common vole) from field measurements.
authors: Department of Environmental Science, Institute for Wetland and Water Research, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands. m.loos@science.ru.nl
authors: Mark
authors: M
authors: Loos
authors: Ad M J
authors: AM
authors: Ragas
authors: Julian J
authors: JJ
authors: Tramper
authors: A Jan
authors: AJ
authors: Hendriks
mesh_terms: D000818:Animals; D003411:Arvicolinae / Q000254:growth & development / Q000378:metabolism*; D004781:Environmental Exposure; D004784:Environmental Monitoring; D020387:Food Chain; D015386:Hazardous Substances / Q000032:analysis / Q000633:toxicity; D016014:Linear Models; D008954:Models, Biological; D009426:Netherlands; D018570:Risk Assessment; D045483:Rivers / Q000737:chemistry; D012788:Shrews / Q000254:growth & development / Q000378:metabolism*; D054928:Validation Studies as Topic; D015032:Zinc / Q000493:pharmacokinetics*
chemical_list: D015386:Hazardous Substances; D015032:Zinc