Water Quality Assessment and Evaluation of the Human Health Risk of Tap Water Use in the Karbala Governorate, Iraq

The availability of tap water sources is an important aspect of public health. Radon concentrations in water are an important source of water pollution. The water quality in seven Karbala sites in Iraq was evaluated using five parameters: temperature (T), total dissolved solids (TDS), pH, electrical conductivity (EC), and salinity (S). The ²²²Rn levels in the tap water samples were studied using a CR-39 detector. The concentrations of radon gas in the tap water samples were less than the accepted international limit of 11.1 Bq L^–1, and the annual effective dose was less than the required international value of 1 mSv year^–1. Therefore, the tap water used in all areas of the Karbala governorate is safe in terms of its ²²²Rn content. Water temperatures in Karbala City are below the Canadian Council of Ministers of the Environment (CCME) standard limit of 15°C, except for the Northern Drainage (Al-Shariea Site), where the temperature is above the limit because of the different intended sampling and the hot Iraqi environment. The TDS difference measured in tap water is greater than the water level limit of 500 mg L^–1 set by the World Health Organization (WHO) and CCME, and the measured pH values were within the standard ranges, 6.5–8.5 and 6.5–9, defined by the WHO and CCME, respectively. All water samples had electrical conductivities above the WHO requirement of 1000 S cm^–1 but below the CCME standard of 1500 S cm^–1. The content of primary cations (Ca²⁺, Mg²⁺, Na⁺, and K⁺) and heavy metals (zinc, copper, nickel, lead, and cadmium) was determined by flame atomic absorption spectroscopy (FAAS),. Primary cations follow the order Na⁺ > K⁺ > Ca²⁺ > Mg²⁺, and heavy metal ions, the order Zn²⁺ > Pb²⁺ > Cu²⁺ > Cd²⁺ > Ni²⁺. The average readings for Pb²⁺ and K⁺ were greater than the optional safe levels recommended by the CCME and WHO.