Spatial Distribution and Temporal Variability of Arsenic in Groundwater Resources of Sirjan Plain

Groundwater contamination is one of the most important threats to natural ecosystems and human health. Therefore, groundwater quality assessment, due to the provision of a large part of agricultural and drinking consumption, is very important and can help improve the management of water resources. One of the causes of groundwater pollution is the existence of heavy metals, especially arsenic, the overload of which causes many problems, such as various diseases. Groundwater pollution with arsenic has been reported in most parts of the world and Iran, specifically Kerman Province. In the present study, spatial distribution and temporal variability of arsenic in groundwater resources of Sirjan Plain, located in Kerman Province, are investigated. For this purpose, sampling was performed from 22 groundwater resources (agricultural wells, drinking water and qanats) with suitable spatial distribution in the plain on the seasonal basis (from winter 2015 to spring 2017) and the amount of arsenic in the water resources was measured. The spatial distribution analysis showed that the concentration of arsenic in groundwater samples varied from 1μg/l to 200 μg/l. The highest concentrations of arsenic was in the northeastern part of the plain and in parts of the central area, and a decreasing trend was found towards the north and south of the plain. It was shown that 68% of the available water was not suitable for drinking. Also, results of the seasonal sampling and the assessment of groundwater level showed that, with the increasing discharge of groundwater resources and reducing level of groundwater, arsenic concentration was increased. It can be concluded that, with the excessive discharge of groundwater and further decrease in the level of groundwater, there was a potential for increasing arsenic concentration.