Arsenic, lead and antimony contamination of the Sefidrud sub-basin (Kurdistan province): An indication for the high incidence of gastric and esophagus cancers in Northwest Iran

Abstract

The Sefidrud sub-basin, extending from Kurdistan to the southern Caspian Sea, is the main drainage basin of the Kurdistan Province. Based on previous works and new field investigation, potentially contaminated areas were identified and approximately sixty groundwater samples were collected from wells and springs during the dry (October 2020) and wet (April 2021) seasons; along with 40 rock and soil samples. After analyzing the samples by coupled plasma mass spectrometry and modeling in ArcGIS software, we present a new dataset of toxic element contamination in the water resources of Kurdistan Province. Higher toxic element concentrations include arsenic, antimony, and lead of which 80, 28, and 13.3% of samples had concentrations higher than WHO guidelines, respectively. The severely contaminated sites mainly include east Qorveh, north and northeast Dehgolan, and south and southwest Bijar, which, based on the data of rock and rock samples, are associated with geological phenomena. A review of published research and comparison of the geology of northwest Iran with that of western and southern Iran implies that the high incidence of gastric and esophagus cancers in northwest Iran is mainly linked to the geology of the contaminated areas, which increases the exposure of the toxic element through drinking and irrigation water. Results indicate that the main sources of toxic elements are geogenic, and are primarily related to geothermal processes and contributions from altered young acidic rocks (mainly resulted from Miocene-Quaternary volcanic activities) of northwest Iran.