Risk Characterization of Contaminated Water Pathways and Toxicity Determination

Abstract

Radionuclide contaminants of most environmental significance are those taken up by plants; and have high rates of transfer to vegetable and animal products, such as crops, milk and meat, and have relatively long radiological half-lives. Soil type (particularly clay mineral composition and organic matter content), tillage practice, and climate affect radionuclide transport to rivers and groundwater. Prior to the Chernobyl accident, the respective concentrations of the ⁹⁰Sr and ¹³⁷Cs in the Pripyat water averaged 0.011 and 0.007 Bq/l. After some rainfalls, the respective concentrations of ⁹⁰Sr and ¹³⁷Cs in the Dnipro and Pripyat rivers ranged from 1.59 to 2.70 Bq/l and from 3.35 to 5.95 Bq/l. In contrast to ¹³⁷Cs, the radionuclide ⁹⁰Sr is transported by streams as a soluble compound (50–99%). Rainfall exacerbated contamination at the Chernobyl site by the addition of airborne radioactive particles (micro- and/or nano-sizes) to surface and ground-water system increasing genotoxicity to plants.