Investigation of arsenic content in drinking water of residents in Inner Mongolia Autonomous Region from 2017 to 2019 / 中华地方病学杂志

ABSTRACT

Objective:To investigate the distribution of arsenic content in drinking water of residents in Inner Mongolia Autonomous Region, and to provide a scientific basis for formulation of detailed prevention and control measures for endemic arsenic poisoning.Methods:From 2017 to 2019, water arsenic survey was carried out in all natural villages in 103 banners (counties, districts) of 12 leagues (cities) in Inner Mongolia Autonomous Region, and drinking water samples were collected according to different water supply modes (engineering water supply, physical and chemical water purification, decentralized water supply). Among them, engineering water supply one factory water sample was collected from each water modification project in dry season and wet season; and one terminal water sample was collected in historical arsenism area/high arsenic exposed villages covered by the project. Physical and chemical water purification one water sample was collected from each household. Decentralized water supply in historical arsenism area/high arsenic exposed villages, one water sample was collected from each household; in the villages with historical qualified water arsenic, one household was selected according to the five directions of east, south, west, north and middle, and one water sample was collected from each household. The content of arsenic in water was detected by atomic fluorescence spectrometry and a distribution map of water samples with excessive arsenic was drawn using ArcGIS 10.2 software.Results:A total of 90 455 water samples were collected, including 31 617 water samples for engineering water supply, 2 702 water samples for physical and chemical water purification, and 56 136 water samples for decentralized water supply. The medians of water arsenic content of engineering water supply, physical and chemical water purification, and decentralized water supply were 1.00, 1.00 and 0.50 μg/L, respectively, and the differences among different water supply modes were statistically significant (χ 2 = 1 147.831, P < 0.05). A total of 486 water samples with excessive arsenic were detected, the detection rate was 0.54% (486/90 455). The detection rates of water samples with excessive arsenic in engineering water supply and decentralized water supply were 1.48% (469/31 617) and 0.03% (17/56 136), the detection rate of water samples with excessive arsenic in engineering water supply was higher than that in decentralized water supply (χ 2 = 775.401, P < 0.05); there was no water samples with excessive arsenic in physical and chemical water purification. The top three areas with the detection rates of water samples with excessive arsenic were Bayannaoer [15.38% (343/2 230)], Hohhot [2.00% (86/4 293)], and Ordos [0.85% (50/5 848)]. ArcGIS 10.2 software showed that the water samples with excessive arsenic were mainly distributed in the western region in the shape of focal and block, and only existed sporadically in the eastern region. Conclusions:The detection rate of water samples with excessive arsenic in engineering water supply in Inner Mongolia Autonomous Region is high, the water samples with excessive arsenic are mainly distributed in the western region in the shape of focal and block, and sporadically in the eastern region. The management and supervision of engineering water supply should be strengthened, in areas where the water arsenic exceeds the standard, we should take physical and chemical water purification measures, such as change water sources, increase water purification equipment, and improve water purification technology to reduce arsenic hazards, so as to ensure that residents can drink qualified water.