Probabilistic Risk Assessment of Nephrotoxic Effect of Uranium in Drinking Water

Abstract

Assessments of the health effects of pollutants generally use models in which exposure variables and model parameters are point values, often chosen as conservative estimates. A more realistic approach is to characterize the uncertainty of each variable and parameter explicitly as a probability distribution. This paper presents a probabilistic version of an established model for metabolism of ingested uranium and characterizes the parameters of the model as distributions. It then characterizes the uncertainty of the threshold level for nephrotoxic risk of uranium, and uses distributions of the heterogeneity in drinking water intake of uranium in the U.S. to assess nephrotoxic risk. It further evaluates the implications of inadequate data on the heterogeneity of dietary intake.

Cancer Incidence and Mortality in Populations Living Near Uranium Milling and Mining Operations in Grants, New Mexico, 1950–2004

“…More recent papers have been published on effects of uranium at levels below 3 µg/g, and those papers have discussed possible mechanisms of uranium toxicity (Diamond 1989;Leggett 1989Leggett , 1994Zhao and Zhao 1990;Morris and Meinhold 1995). It is thought that the kidney may develop an acquired tolerance to uranium after repeated doses; however, this tolerance involves detectable histological (structural) and biochemical changes in the kidney that may result in chronic damage.…”

“…The researchers proposed that the severity of effects increases with increasing dose to the kidney with probably no effects below 0.1 to 0.2 µg/g, possible effects on the kidney at 0.5 µg/g, more probable effects at 1 µg/g, and more severe effects at 3 µg/g and above (Morris and Meinhold 1995;Killough et al 1998b). …”

“…ATSDR's health-based guidelines for ingested (and inhaled) uranium are lower than the lower limit threshold for kidney toxicity proposed by Morris and Meinhold (1995). ATSDR's guidelines are derived by use of levels of toxicity observed in animal studies, and those guidelines incorporate safety factors to account for uncertainty in extrapolating from animals to humans and to protect the most sensitive human individuals (ATSDR 1992).…”

Ground Water Ingestion Dose Due to Intake of Radionuclide (Natural U and 226Ra) to Population Around Uranium Mining Complex at Jaduguda

“…Though, intake of uranium by members of the public can occur through various routes. However the principal route of ingestion of uranium is through drinking water [18] and to a lesser extent through the foodstuff. Intake of uranium through drinking water by population residing around the uranium mining area has been considered in the present study.…”

Fission track estimation of uranium concentrations in liquid homeopathic medicine samples

“…Chemically, its hexavalent state is particularly important because of its adverse health effects as it can damage the kidneys, preventing normal elimination of urea and other waste products, resulting in renal dysfunction. Therefore, it may be hazardous if inhaled or ingested in excessive quantities (Cothern and Lappenbusch, 1983;Leggett, 1989;Morris and Meinhold, 1995;Kurttio et al, 2002). Hence the assessment of high concentration of uranium in medicine is most important.…”