摘要
吉林省饮水型砷中毒区是继中国内蒙古和山西病区后发现的新病区。该病区主要分布在吉林省西部的通榆县和洮南市,其水文地质单元属于松嫩平原大型蓄水盆地的西部,是由第四系潜水、承压水和新近系承压水组成的多层结构的含水系统。采用瞬时采样法采集了区内潜水和承压水样品,共194份;通过GIS的空间叠加技术、化验与测试技术,进行了区域水化学环境特征与饮水型砷中毒的关系研究。结果表明：受区域地质构造控制,在低洼地带堆积了巨厚的粉砂淤泥质冲积物和富含有机质的湖积物,为地下水砷的赋存提供了空间。区域地下水砷含量的范围值为0.001~0.339mg·L-1,水砷价态以As（V）为主,高砷水主要分布在由若干隆起形成的中间低洼地带中地下水埋深大于10m的潜水、第四系和新近系承压水含水层中。高砷地下水的形成与特定的水文地质条件和水化学环境有关,氯化物-重碳酸钠型水中的砷含量最高。臭葱石（FeAsO4·2H2O）等含铁、含锰矿物在进入地下水的溶解过程中,形成铁、锰的氧化物和砷的化合物,如砷酸盐和亚砷酸盐。伴随着水环境中Eh的降低,氧化物被还原形成更为活泼的离子组分,吸附在氧化物表面的含砷化合物进而解吸,使砷从含水层的沉积物中向水中溶解和迁移。
The arsenism area of drinking water type in Jilin Province of China is a new endemic area,which was found after the endemic areas in the Inner Mongolia and in Shanxi Province.The endemic area mainly belongs to Tongyu County and Taonan City of the western Jilin Province.Its hydrogeological unit is part of the west of the large water storing basin of Songnen Plain.The aquifer system consists of Quaternary phreatic and confined water and Neogene confined water.A total of 194 groundwater samples were collected with instantaneous method from phreatic and confined aquifers.By GIS spatial overlay technology and laboratory and testing technology,the research on the relationship between the characteristics of regional hydrochemical environment and arsenism of drinking water type was conducted.The results show that the very thick silty mud alluvium and the lake sediments rich in organic matter accumulated in depression areas provided the space for groundwater arsenic by the regional geological structure control.The total arsenic concentration ranges from 0.001to 0.339mg·L-1,and the valence of arsenic is mainly As（V）.The distribution of arsenic at the present time has close relationship with the spatial variation of Fe,Mn,as well as Cl-,PO3-4,HCO-3and SO2-4.The high arsenic samples were mainly in the depression areas around with some uplifts,where the depth is more than 10min the aquifer of phreatic water and of Quaternary and Neogene confined water.The formation of the high arsenic water was related to the specific hydrogeological condition and hydrochemical environment.The highest arsenic content was found to be the water of chloride-sodium bicarbonate type.The dissolution of the redox sensitive iron and manganese oxide compound and hydroxide as well as the arsenic compounds（arsenate or arsenide）are likely the major mechanisms in controlling its spatial variation of arsenic in the study area.In the dissolution process of the groundwater,the scorodite（FeAsO4·2H2O）and other iron and manganese minerals formed iron and manganese oxides and arsenic compounds,such as arsenate and arsenite.With the decrease of Eh in the water,the oxides were reduced to form more active ions.And the arsenic compounds adsorbed on the surface of the oxide dissolved and precipitated.Then the arsenic dissolved and migrated from sediments in the aquifer to the water.The study finally concludes that the presence of arsenic in regional groundwater flow regime exhibits the highest concentration in chloride-sodium bicarbonate groundwater in the central area,which is consistent with the above findings and many previous studies of the international community in this special field.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2014年第4期30-36,共7页
Earth Science Frontiers
基金
中国地质调查局项目(1212010634701)
吉林省地质调查局项目(1212010511208)
吉林省环境保护厅重点科技项目(20070101)
关键词
砷中毒
地下水
水化学环境
砷的价态
成因分析
arsenism
groundwater
hydrochemistry environment
the valence of arsenic
cause analysis
