陕南地方性砷中毒病区人群尿中不同化学形态砷含量调查

An investigation on arsenide valence and speciation in urine of people in the endemic arsenism areas in the south of Shaanxi Province

目的了解陕南地方性砷中毒病区暴露人群尿中不同化学形态砷含量和总砷（total arsenic，TAs）含量以及与砷中毒的关系。方法根据砷中毒调查历史资料，选择陕南安康市的紫阳、平利2个县的11个病区村作为调查点。选择与其邻近且自然环境与生活习惯相近的非病区白河县的3个村镇作为对照点。在调查点分采暖及非采暖两季，抽取40岁以上人群做流行病学调查，然后按病情分层，每季每层收集尿样约40份；对照点抽取40岁以上人群，两季分别收集尿样约20份。采用氢化物发生-原子荧光法（HG-AFS）测定TAs，液相色谱-氢化物发生．原子荧光法（LC-HG-AFS）测定无机3价砷（As^3＋）、二甲基砷（DMA）、一甲基砷（MMA）和无机5价砷（As^5＋），对不同地区、病情、年龄、性别、季节的人群尿中不同化学形态砷和TAs含量进行比较。结果病区人群尿中总TAs、As^3＋、DMA、一甲基化率（PMI）、二甲基化率（SMI）的中位数（35．3、2．2、24．5μg／L，0．84、0．90）显著高于对照人群（16．0、0．6、10．3μg/L，0．78、0．81；Z=-9．069、-7．314、-8．913、-2．183、-3．853；P〈0．01或〈0．05），且病区正常人群尿中TAs、As^3＋、DMA、SMI（31．6、2．0、23．1μg／L，0．91）也显著高于对照人群（Z=-7．164、-6．136、-7．023、-2．916，P均〈0．01）。砷中毒病情与TAs、DMA、年龄呈正相关关系（r=0．370、0．367、0．594，P均〈0．01）。男性砷中毒检出率、TAs、As^3＋、DMA（59．9％，37．4，2．5、25．2μg／L）明显高于女性（22．4％，30．0、1．6、20．9μg／L；χ^2=54．878，P〈0．01；Z=-3．332、-4．449、-2．681，P均〈0．01）。采暖季As^3＋、MMA、As^5＋、PMI、SMI（1．5、2．1、1．4μg／L，0．87、0．92）与非采暖季（2．6、3．3、3．0μg／L，0．82、0．88）比较差异有统计学意义（Z=-6．870、-5．512、-8．542、-2．262、-4．544，P〈0．01或〈0．05）。结论人群尿样中TAs、As^3＋、DMA含量与当地砷含量有关，在病区的确定上有一定的参考意义。男性与女性比较。为较高的砷中毒易感人群。

Objective To investigate the urinary arsenic levels of exposed population in various forms of and total arsenic （TAs） content as well as their relationship with arsenic poisoning in southern Shaanxi arsenic poisoning area. Methods According to the historical data of the investigation on arsenic poisoning, 11 disease villages were chosen as survey sites in Ziyang and Pingli counties, Ankang city; three neighbor villages were chosen as control sites in Baihe. Baihe was a non-endemic arsenic poisoning area county, which had the same natural environment and living habits. In the survey sites, people over the age of 40 were selected for epidemiological investigation in both heating and non-heating seasons, and 40 urine samples were collected at each severity levels of the disease and in different seasons. Meantime, 20 urine samples of the same age group were collected in the control sites in each season. Hydride generation-atomic fluorescence spectrometry （HG-AFS） was used to determine TAs, liquid chromatography-hydride generation-atomic fluorescence spectrometry （LC-HG-AFS） was used to determine the amount of inorganic trivalent arsenic （As^3＋）, dimethylarsine （DMA）, monomethylarsine （MMA） and inorganic pentavalent arsenic （AS^5＋）, and the various forms and TAs were compared between different survey sites , severity levels, ages, sexes, and seasons. Results The medians of TAs, As^3＋, DMA, primary methylation index （PMI）, and secondary methylation index （SMI） in diseased area （35.3, 2.2, 24.5 μg/L; 0.84, 0.90） were significantly higher than those of the control group （16.0, 0.6, 10.3 μg/L; 0.78, 0.81; Z = - 9.069, - 7.314, - 8.913, - 2.183, - 3.853, P 〈 0.01 or 〈 0.05）, and the medians of TAs, As^3＋, DMA, and SMI （31.6, 2.0, 23.1 μg/L; 0.91） of the normal population in the diseased area were significantly higher than those of the control group （16.0, 0.6, 10.3 μg/L; 0.81; Z = - 7.164, - 6.136, - 7.023, - 2.916, all P 〈 0.01）. Illness had positive correlations with TAs, DMA, and ages （r = 0.370, 0.367, 0.594, all P 〈 0.01）. Men arsenic poisoning detection rate, TAs, As^3＋, and DMA （59.9%, 37.4, 2.5, 25.2 μg/L） were significantly higher than those of women （22.4%, 30.0, 1.6, 20.9 μg/L; χ^2 = 54.878, P 〈 0.01; Z = - 3.332, - 4.449, - 2.681, all P 〈 0.01）. The medians of As^3＋, MMA, As^5＋, PMI, and SMI in the heating season （1.5, 2.1, 1.4 μg/L; 0.87, 0.92） were significantly different from those in the non-heating season （2.6, 3.3, 3.0 μg/L; 0.82, 0.88; Z = - 6.870, - 5.512, - 8.542, - 2.262, - 4.544, P 〈 0.01 or 〈 0.05）. Conclusions The TAs, As^3＋, and DMA of urine samples are related to local arsenic background, so they have some reference value for determination of diseased areas. Men are more susceptible to arsenic poisoning than women.