Iowa Population Exposures to Metals and Metalloids in Well Water

Previous Iowa studies suggest low levels and chronic arsenic exposures are associated with prostate cancer. The rural Iowa population heavily relies on private wells for drinking water resources and thus is vulnerable to contaminants such as heavy metals found in well water. The Iowa Biomonitoring Program focuses on determining the extent of chemical exposure through urine biomarker testing in the rural Iowa population which uses private well water as their primary drinking water source. Besides the previously identified high risk of arsenic, the current exposure study expands to a panel of 16 elements such as lead, arsenic, cadmium, barium, strontium and uranium. The State Hygienic Laboratory at the University of Iowa (SHL) enrolled 1189 participants for the private well study for surveillance of arsenic and other elements of interest as part of a larger surveillance effort. Water samples and urine specimens were collected by 1018 participants and sent to the State Hygienic Laboratory for analysis. Analytical methods used for the determination of elements in water and urine were validated prior to use and were based on established methods from the Centers for Disease Control and Prevention (CDC). Water samples and urine specimens were analyzed for lead, cadmium, uranium, arsenic, tin, strontium, cobalt, thallium, manganese, barium, beryllium, molybdenum, tungsten, cesium, platinum, and antimony. The initial analysis of the data indicates statistically significant positive correlations between well water and urinary concentrations of arsenic, uranium and strontium (Spearman's rank-order correlation coefficients of 0.230, 0.466, and 0.314, respectively). Cadmium, lead, and other metals tested showed no significant correlation with well water. For the first time in Iowa, we identified a moderate association of urine uranium to uranium found in well water. This suggests that exposure to uranium is occurring by drinking well water. In addition, the correlation of arsenic in well water and urine showed a weak positive association as evidence of exposure to arsenic from drinking well water. Strontium was also correlated in urine and well water. Participants whose well water had arsenic levels at or above the maximum contaminant level (MCL) were contacted to increase awareness of the risk of arsenic exposure. Most of the participants indicated they had water treatment systems in use which may explain the weak correlation and give supporting evidence of public health outreach in the area.