Comparative health risk assessment of nitrate in drinking groundwater resources of urban and rural region(Isfahan, Iran), Using GIS

Abstract

Abstract Background : Groundwater contaminant such as nitrate (NO 3 - ) is one of the environmental factors that can affect human health . Methemoglobinemia of infants, thyroid disorders, and probably some carcinogenic effects, are health concerns associated with dietary nitrate. Isfahan province has a dry and semi-arid desert climate that the main source of various applications in this province is groundwater resources. This study evaluated spatial analysis of the concentration of NO 3 - in groundwater resources and its possible health risk to residents. Results : It was indicated that nitrate concentrations in the rural and urban areas were in the range of 0.4–137 mg/L NO 3 − with the mean of 33.72 mg/L NO 3 − , and 2.9-209 mg/L NO 3 - with the mean of 38.87 mg/L, respectively. As well, 226 samples (25%), and 104 (24%) ones were detected above the Iran and World Health Organization guidelines 50 mg/L as NO 3 − . While the highest levels of NO 3 − which were located in the west and central groundwater resources of the province were in the agricultural and residential areas. The HQ for Infants, in 32% of samples, urban 136 and rural 297 samples were higher than 1 (HQ>1). Also, in urban area HQ was more than 1 in 8, 5, 1, and 3 samples in children, teens, male and female, respectively. Conclusions : Infants were the most vulnerable compared with the other groups. Therefore, in some areas, there are potential risks of methemoglobinemia, especially for infants. So, it is critical to adopt specific strategies to reduce the nitrate concentration in the studied groundwater.