中国饮水型砷中毒区的水化学环境与砷中毒关系

中国各饮水型砷中毒区的水化学特点受沉积环境和气候因素所控制,砷中毒的流行和发病程度与其地下水的水化学环境、水中砷的形态和价态有密切联系。在实地考察监测和对台湾、新疆、内蒙古、山西、吉林饮水型砷中毒病区环境和地下水水化学特征总结的基础上,系统分析了饮水水源中总As、As(III)、甲基胂、腐植酸与砷中毒的关系,揭示了不同病区病情差异的原因。研究表明,除台湾外,各砷中毒区均分布在干旱半干旱区;各病区多分布在沉积盆地中心或平原内相对低洼的地带,饮用的地下水均取自中新生代地层;砷中毒病情不仅与总砷含量有明显的剂量-效应关系,还与As(III)和甲基胂的浓度直接相关。台湾、内蒙古和山西病区地下水为富含有机质的复杂还原环境,水中不仅As(III)含量高,且检出有机物、腐植酸和甲基胂,新疆和吉林病区地下水为以无机砷中As(V)为主的氧化环境,吉林病区未检测出甲基胂,这是新疆与吉林病区患病率较低的主要原因。研究成果可为区域防病改水、砷中毒的预报提供重要技术支撑。

Relationship between Hydrochemical Environment and Arsenism in Areas with Arsenic Poisoning Drinking Water in China

Hydrochemical characteristic of drinking water in arsenism areas, is dominated by depositional environment and climatic factor in China. The arsenism prevalence and disease extent are closely related with its groundwater hydrochemical environment, arsenic morphology and valence. Based on field investigation, samples detection and analysis of the environment and groundwater hydrochemical characteristics of drinking water type arsenism areas were carried out on Jiayi and Nantai County of Taiwan Province, Kuitun City of the Xinjiang Uygur Autonomous Region, the Yellow River Hetao Plain in Inner Mongolia Autonomous Region, Datong City of Shanxi Province and the western of Jilin Province. The relationship between arsenism and total arsenic, As(III), monomethyl arsine and humic acid were analyzed in different areas and the reasons for the differences of disease extent between arsenism areas were discussed. Results showed that the arsenim areas are distributed in the arid and semi-arid area except Taiwan. The illness areas are mainly located in the center of sedimentary basins and low-lying areas of plain, where the drinking groundwater is taken from Mesozoic and Cenozoic layer. A significant dose-response relation was observed between disease condition of arsenism and the total arsenic levels as well as the contents of As(III) and monomethyl arsine. Not high content of As(III) and organic matter, but humic acid and monomethyl arsine were detected in groundwater in Taiwan, Inner Mongolia and Shanxi where the groundwater is in complex organic-rich reduction environment. By contrast, the high arsenic groundwater in Xinjiang and Jilin are in oxidation environment mainly with inorganic arsenic As(V), which is the main reason for the low prevalence in these areas. The researches provide important technical support for regional disease prevention and water improvement and forecasting of arsenism.