While the analysis of total arsenic in urine by ICP-MS is a rapid and accurate determination of a person’s arsenic exposure, the effects of the exposure are dependent on the physical and chemical properties and toxicity of different arsenic species. Inorganic arsenic is a naturally occurring element found in soil and in some types of pesticides, treated wood, and other products. Organic arsenic, on the other hand, is found in food, specifically seafood, and is relatively non-toxic. Coupling liquid chromatography to an ICP-MS (LC-ICP-MS) allows for the accurate determination of several arsenic species. We used this method to analyze children’s urine as part of the Minneapolis Children’s Arsenic Study.
The Minneapolis Children’s Arsenic Study is one component of the Minnesota Biomonitoring Program conducted by the Minnesota Department of Health. This study examined the urine of 65 children, ages 3 – 10, for arsenic exposure. The children involved in the study live near the former CMC Heartland Lite Yard site, where arsenic-containing pesticides were manufactured and stored between 1938 and 1963. We will present our ICP-MS method for measuring total arsenic concentrations for all 65 study participants. We found that approximately one third of study participants’ samples had total arsenic concentrations high enough to warrant speciation analysis. We will present our LC-ICP-MS method for determining the concentrations of six arsenic species. We found that all speciated samples contained low levels of the inorganic arsenic metabolite, dimethyl arsinic acid. In addition, we found that the urine samples for the three children who had above-normal levels of total arsenic contained predominantly the organic, or relatively non-toxic, arsenic species. |
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