Investigation of the epidemiology of endemic arsenism in Ying County of Shanxi Province and the content relationship between water fluoride and water arsenic in aquatic environment

Objective To investigate the epidemical range, the distribution features and the state of endemic arsenism in Ying County. Methods According to the demand of The National Distribution Investigation and Implementation Project for Endemic Arsenism, an epidemiological investigation on the arsenic content in drinking water and the population exposed to arsenic in Ying County was carried out by screening methods. Arsenic contents in drinking water, urine of arsenism sufferers, local food as well as fluoride content in drinking water were determined. Results It had been observed that 16.49% of the water samples tested exceeded the national quality standard of 0.05 mg/L for drinking water. Water fluoride content varied in water with different content of arsenic (F = 21.83, P 0.01). Water arsenic content tended to increase along with the depth of wells (F = 187.53, P 0.01) but that of fluoride tended to decrease (F = 27.98, P 0.01). 26.37% of the urine samples tested from arsenism sufferers exceeded the national standard. All food samples tested were within the national standard level. 216 patients with endemic arsenism were discovered, 18 diseased villages were confirmed to be the districts of slight arsenism and 16 482 people lived in the area of high-risk. Conclusions Ying County is widely exposed to high arsenic, however, the local people drink arsenic water just in a short period, and thus the situation isn't serious. Since the wells of low content of fluoride and arsenic are mostly sunk about 50m under beneath, hygiene water resource should be chosen safely according to the local conditions to ensure the success of the preventive countermeasures of defluoridation and arsenic removal.