2025/07/14 by Catherine M. Lucey, Brandon L. Pearson, Kathryn DeSantis +5 · 1 citation
Chemistry · Health Professions · Environmental Science · #Radioactive element chemistry and processing #Radioactivity and Radon Measurements #Mercury impact and mitigation studies
paper · doi:10.1021/acs.est.5c03403
Chronic low-level uranium (U) exposure through drinking water is a public health risk in the United States. Nearly two-thirds of community water systems, serving 320 million people, have detectable U levels, with 2% exceeding the EPA’s maximum contaminant level of 30 μg/L. Ingested U accumulates in kidneys and is nephrotoxic at high levels. Uranium binds to proximal tubule cells, causing injury and interfering with kidney function. Epidemiological studies suggest that even low-level (<30 μg/L) of U exposure could damage kidneys. Current biomarkers, like urinary U levels, fail to indicate tissue-specific concentrations and metabolic interactions in kidneys. Fractionation of 238 U/ 235 U may potentially serve as a biomarker for the metabolic interaction of U with organs. Our experiments with mice showed changes in U isotopic composition ( 238 U/ 235 U expressed as δ 238 U) in organs after administering 50 mg/L U via drinking water for 2, 7, and 14 days. We found 235 U enrichment in kidneys and bones, the target organs, while urine was enriched in 238 U. Our results provide evidence of isotopic fractionation resulting from U accumulation in kidneys. Urinary U isotopic composition may, thus, provide a sensitive, noninvasive measurement of renal U bioaccumulation that could aid early detection of nephrotoxicity and prevention of irreversible kidney damage.