THE CR CONCENTRATION IN GROUNDWATER RESOURCES AND ITS RENAL DAMAGES (PROTEINURIA) IN BIRJAND, NE IRAN

Due to supplying the most potable water of the Birjand and southern villages from ophiolite units, it is essential to investigate the concentration of Cr in groundwater resources, and also the health effects of Cr-contaminated water consumption (i.e. proteinuria) among residents. To achieve this aim, 15 groundwater samples and 200 urine samples (100 samples from each Birjand and Qaen residences, as case and control groups, respectively) were collected. The concentrations of Cr, major cations/anions in water samples were measured in the geochemistry laboratory of university of Ottawa using ICP-AES and IC, respectively.Urinary Cr concentration was detected using GFAA in Toxicology Laboratory of Mashhad IR Hospoital, serum creatinine was detected in Birjand IR Hospoital, and urine protein was determined in Birjand University of Medical Sciences.

The results of this Study show that the ultramafic and mafic rocks (ophiolite unites) have a large impact on groundwater resources of the area. The maximum concentrations of Cr in rural drinking water and in Birjand aquifer are 0.05 ppm and 0.12 ppm, respectively. According to the pH of sediments and Eh-pH diagram of water samples, the Cr in water resources is as Cr (VI). The composition diagrams and Gibbs model of water samples show that the weathering of silicate rocks (ultramafic rocks) is the most important factor controlling the chemistry of groundwater resources which mostly have magnesium bicarbonate type.

Based on the obtained data, the mean concentrations of Cr and Cr/creatinine in case group (Birjand) was higher than the that of the control group (Qaen) and there is no significant relationship between the protein/creatinine ratio and mean Cr/creatinine. However, the mean Cr concentration in the urine samples of case group (7.6 µg/l) is much higher than that of the control group (1.4 µg/l) and normal human urinary concentration (0.6 µg/l). In terms of correlation of the source of drinking water and urine Cr concentrations, the present study showes that the Cr concentrations in the urine of people who are drinking purified water is significantly lower than that of individuals who are using municipal tap water and water purification simultaneously. Therefore, it seems that water purification plays an important role in reducing of Cr intake by individuals.