Analysis of surveillance results of water-borne endemic arsenism in Inner Mongolia in 2015

Objective To understand the changes of arsenic poisoning in drinking water arsenic poisoning areas in Inner Mongolia Autonomous Region, to provide a scientific basis for timely adjustment of local arsenic poisoning prevention and control measures. Methods In accordance with the requirements of the national "Surveillance Scheme of Drinking-Water-Borne Endemic Arsenism", 38 villages were selected from 8 cities as monitoring sites in Inner Mongolia Autonomous Region in 2015. The situation of the villages in improving water quality and operation of the arsenic reducing projects was investigated, water samples were collected to detect water arsenic content of all the monitoring villages exposed or previously exposed to high arsenic water in the resident population, and 30 adult patients with arsenic poisoning were tested urine arsenic level. Results Thirty-eight monitored villages had changed the water sources; the change rate was 100.00% (38/38) . Water arsenic content qualified projects were 17, covering 36 villages. The project with water arsenic content exceeded the national standard was 1, the rate of exceeded standard was 5.56% (1/18), covering 2 monitored villages. In the 36 water arsenic content qualified natural villages, 4 163 people were examined, and arsenic poisoning patients detection rate was 10.21%(425/4 163). The incidence of mild, moderate, severe and skin cancer cases was 7.59% (316/4 163), 1.68% (70/4 163), 0.86% (36/4 163) and 0.07% (3/4 163), respectively, no new cases and new skin cancer cases. In the natural villages where the content of arsenic in water exceeded the standard, 461 resident people who were drinking high arsenic water were examined. The detection rate of arsenic poisoning patients was 3.69% (17/461), no moderate, severe, new and skin cancer cases. A total of 1 107 patients with arsenic poisoning were tested for urinary arsenic levels in the 36 villages with normal water available and water arsenic levels in the range of 0.000-0.441 mg/L with a median of 0.011 mg/L. The content of urinary arsenic in 60 patients with arsenic poisoning was detected in the 2 natural villages with the arsenic content exceeded the standard. The range was 0.030-0.268 mg/L and the median was 0.155 mg/L. Conclusions The projects of anti-arsenic water have effects in Inner Mongolia Autonomous Region. But there are still water projects with water arsenic content exceeded the standard, which seriously affects the health of residents, and the water management and maintenance of water projects needs to be strengthened. Key words: Arsenic poisoning; Water improvement project; Monitoring results