Toxicological risk assessment of protracted ingestion of uranium in groundwater.

Abstract

Groundwater samples have been collected from far-reaching locations in Solan and Shimla districts of Himachal Pradesh, India, and studied for uranium concentration using LED fluorimetry. In this region, uranium in groundwater varies from 0.12 to 19.43μgL-1. Radiological and chemical toxicity is accounted for different uranium isotopes. The average mortality risk for uranium isotopes 234U, 235U, and 238U are 2.6 × 10-12, 3.5 × 10-10, and 5.9 × 10-8, respectively. Similarly, the mean morbidity risk for 234U, 235U and 238U are 4.1 × 10-12, 5.6 × 10-10 and 9.5 × 10-8, respectively. An attempt has also been made to calculate doses for different age-groups. Highest doses, ranging from 0.30 to 48.23µSvyear-1, are imparted to infants of 7-12months of age which makes them the most vulnerable group of population. Using Hair Compartmental Model for uranium and mean daily uranium intake of 3.406μg for 60-year exposure period, organ-specific doses due to uranium radioisotopes, retention in prime organs/tissues and excretion rates via urine, feces and hair pathway are estimated. In this manuscript, the transfer coefficients for kidney, liver, skeleton, GI tract, soft tissues, urinary bladder, and blood are analyzed. Hair compartment model and ICRP's biokinetic model are compared in terms of uranium load in different organs after 60years of protracted ingestion. The study on biokinetic behavior of uranium is the first of its kind in the area which is dedicated to environmental and social cause.