Uranium exposure to a community population: renal proximal tubule damage and other biomarkers of renal function

Abstract

Background: We evaluated uranium exposure estimates, urine uranium and biomarkers of renal function in the Fernald Community Cohort (FCC), a volunteer population who lived within 5 miles of a uranium ore processing plant in Fernald, OH, USA during plant operation (1951-1989) and followed 1990-2008 in a medical monitoring program which included clinical laboratory measurements of biomarkers of renal function. Uranium plant workers were excluded. Materials and Methods: Releases of soluble and insoluble uranium particulates from this plant during operation from 1952-1989 were used by the US Centers for Disease Control and Prevention in developing dose estimation models, and we used this algorithm to estimate U exposure for 8770 persons in the FCC. We conducted a validation study of 189 members of the cohort, selected on exposure criteria (highest exposure scores, with and without a well or cistern as a drinking water source). Urine samples of these 189 persons, collected in the early 1990’s, were submitted to the US Armed Forces Institute of Pathology for urine U measurements. Results: Urine uranium (U) levels for most of this study sample were within the 1999-2000 NHANES normal population 95% reference interval (0.006-0.009 ?g/gr Cr); 12% were above the 95th% value. Geometric mean concentrations were highest for those using a well (0.010 ug/gCr) or cistern (0.009 ug/gCr) as a drinking water source compared to those living far from the plant (0.007 ug/gCr). A strong correlation existed between urine U and urine ? -2-microglobulin (?2M, a biomarker of renal proximal tubule function) in sub-groups of those with high ?2M (R=0.664-Spearman), and a mild correlation among those using a well (R=0.238, Pearson) or cistern (R=0.218, Spearman) as drinking water source. Serum creatinine, blood urea nitrogen and urinary microglobulin also were associated with urine U. Conclusions: Chronic, low dose uranium exposure including soluble uranium particulates is reflected by urine U concentration and is associated with renal health effects.