Evaluation of radon concentration and heavy metals in drinking water and their health implications to the population of Quetta, Balochistan, Pakistan

The purpose of this study is to estimate the concentrations of radon and heavy metals in drinking water and assess their health implications to the population of Quetta, Pakistan. The concentration of radon and heavy metals was measured in drinking water collected from tube wells of different depths of the Quetta, Balochistan, Pakistan, using RAD7 detector and Atomic Absorption Spectrometer, respectively. The results show that the concentration of radon ranged from 3.56 +/- 0.98 to 8.56 +/- 1.32Bq/L with an average of 5.67 +/- 1.34Bq/L. The average value of contribution of radon in water to indoor air was found 2.02 +/- 0.47mBq/L. In addition to concentration of radon in drinking water, physiochemical parameters like pH and electrical conductivity (EC), and annual effective doses for different age groups were also estimated. Positive correlation of (R-2 = 0.8471) was observed between depth of well and concentration of radon, however no such relations were found among pH and EC with concentration of radon. Average values of annual effective doses due to intake of radon for age groups 0-1 years (infants), 2-16 years (Children) and >= 17 years (adults) were found (3.00 +/- 0.71)x10(-2), (1.1 +/- 0.26)x10(-2) and (1.45 +/- 0.34)x10(-2) mSv/y, respectively. Average values of heavy metals concentrations were found 1.85 +/- 0.64, 3.21 +/- 0.75, 5.06 +/- 1.19, and 2.47 +/- 0.77 and 5.58 +/- 1.23 mu g/L for As, Cr, Ni, Cd and Pb, respectively. The values of radon concentration and heavy metals in drinking water were found below the USEPA permissible limits, Thus we conclude that, the investigated waters are safe.