加油站地下水中甲基叔丁基醚污染特征

Pollution Characteristics of Methyl Tert-Butyl Ether in Groundwater of Gas Stations

为研究加油站地下水中甲基叔丁基醚(MTBE)的污染特征,对上海市14个行政区71个加油站周边地下水中的MTBE进行为期1年的系统监测及健康风险评估。结果表明,上海市各区加油站地下水中MTBE普遍有检出,检出质量浓度在ND~11919μg/L(ND表示未检出),且各点位的MTBE浓度差别较大。在71个点位中,MTBE的检出点位数有59个,超标点位数有24个,总检出率、总超标率分别为83.1%、33.8%。从第1~4季度,MTBE的检出率和超标率都呈增长趋势,表明地下水中MTBE的污染程度逐渐增强。同时,地下水中MTBE浓度和石油烃浓度呈显著正相关关系,说明MTBE污染很可能源于油品存储、使用过程的泄漏。对24个MTBE超标点位进行健康风险评估结果显示,从第1~4季度,共计有11次MTBE的浓度已超健康风险临界值,可能对人体健康造成风险,有2次的MTBE浓度在临界值附近,需警惕。随着时间推移,MTBE对人体健康造成的风险正逐渐增加。此外,对地下水中MTBE浓度进行了风险评估,确定MTBE风险控制值为1.9μg/L。

In order to investigate the pollution characteristics of methyl tert-butyl ether(MTBE)in groundwater of gas station,one year system monitoring of MTBE in groundwater around 71 gas stations in 14 administrative regions of Shanghai was conducted.The monitoring results showed that MTBE was generally detected in the groundwater of gas stations in most districts of Shanghai.The detection mass concentration range of MTBE was ND~11919μg/L(ND indicated not detected)and the MTBE concentration showed significant difference among various points.The total detection and the over-standard rate of MTBE was 83.1%and 33.8%,respectively.From the first quarter to the fourth quarter,the detection rate and the over-standard rate of MTBE showed an increasing trend,indicating that the pollution level of MTBE in groundwater was gradually increasing.At the same time,MTBE concentration in groundwater was highly positively correlated with petroleum hydrocarbon concentration,indicating that MTBE pollution may be caused by oil leak during storage and use process.The health risk assessment results of 24 MTBE exceeding standard points showed that,from the first quarter to the fourth quarter,the concentration of MTBE had exceeded the health risk threshold for 11 times,probably threatening to human health.The MTBE concentration got close to the critical value for two times,being a warning sign.The risk of MTBE to human health was gradually increasing over time.Also,a risk assessment was conducted on the MTBE concentration in groundwater,and the MTBE risk control value was determined to be 1.9μg/L.