龙南足洞稀土矿区地下水水质特征及健康风险评价

随着长时间对离子型稀土矿的过度开采,其矿区及周边生态环境治理刻不容缓。为提供原地浸矿开采技术导致的矿区及周边地下水污染的修复科学依据,对龙南足洞稀土矿区地下水进行监测,运用修正的内梅罗指数法和健康风险模型进行地下水质综合评价和暴露风险评估。结果表明：浸矿期间污染物在地下水中的迁移缓慢,对浅层地下水的影响大。随着距离和时间的增长,污染物浓度降低。矿区内地下水水质极差,铅超标率为31.71%,硫酸根超标率为4.88%,氨氮超标率为53.66%,氨氮迁移距离为3500米。该地区地下水污染物健康风险指数依次为铅>氨氮>硝酸盐氮>亚硝酸盐氮,幼儿、儿童和成人非致癌风险指数超标率为7.32%、4.88%、0.48%。

Groundwater quality characteristics and health risk assessment in Longnan zudong rare earth mine

With the over-exploitation of ion-type rare earth ore for a long time, it is urgent to control the ecological environment of its mining area and its surroundings. In order to provide scientific basis for remediation of groundwater pollution in mining area and surrounding areas caused by in-situ leaching mining technology, groundwater monitoring was carried out in Longnan zudong rare earth mining area, comprehensive underground water quality assessment and exposure risk assessment were carried out by using modified Nemerow index method and health risk model. The results showed that the pollutants moved slowly in the groundwater during leaching and had great influence on the shallow groundwater. With the increase of distance and time, the pollutant concentration decreased. The groundwater quality in the mining area was extremely poor. The lead exceeding standard rate was 31.71%, the sulfate exceeding standard rate was 4.88%, and the ammonia nitrogen exceeding standard rate was 53.66%. The migration distance of ammonia nitrogen was 3500 meters. The health risk index of groundwater pollutants in this area was lead > ammonia nitrogen > nitrate nitrogen > nitrite nitrogen, and the non-carcinogenic risk index of young children, children and adults exceeded the standard rate of 7.32%, 4.88% and 0.48% respectively.