Mercury distribution and excretion in prairie voles following exposure to methylmercury and chelation treatment

Abstract

2,3-Dimercapte-1- propane-sulfonic acid (DMPS) is a known chelator of heavy metals such as mercury, arsenic, and lead. DMPS can remove these metals from soft tissue and allow metal excretion via urine. The efficiency of DMPS as a chelator of mercuric and methylmercury ions was tested. Methylmercury (MeHg) doses of 0.00 mg/L, 0.01 mg/L, 0.10 mg/L, and 1.00 mg/L MeHg were provided to a total of 260 prairie voles (Microtus ochrogastoi) in water for 0, 3, 6, or 12 weeks. Non-chelation and pest-chelation urine, kidney, liver, and brain were collected from equal numbers of voles at each time point. Samples were digested in strong base and treated with stannous ion or borohydride to allow Hg"^^ and MeHg"^ speciatien via cold vapor atomic absorption. Results of the project showed a significant increase in urinary mercury species from nen-chelation to post-chelation samples and in DMPS treated vs non-DMPS treated voles. Results indicate a correlation between analyte concentrations in tissues versus dosages (r^=0.32 to 0.99). Significant correlations (p<0.001) were also found among analyte concentrations in tissues. Regressions of toxicant concentrations in target tissues were then developed to evaluate the Hg and MeHg distribution and excretion ever the 12 weeks of dosing. While providing important pharmacokinetic information, these studies also establish the foundation for non-lethal monitoring of wildlife exposure to metals.