上海市河网水体中As的分布特征及其生态风险评价

2012年4月,在上海市河网采集表层水和沉积物样品各53个,测定其As含量,并采用潜在生态风险指数法对沉积物As的污染状况进行了评价。研究结果表明,上海市河网表层水和沉积物中As的含量分别为0.47～8.84μg·L-1和3.72～12.65μg·g-1,其中表层水中As的浓度处于中国地表水环境质量标准Ⅰ类水平,沉积物中As的浓度有15个样点超过了上海市土壤背景值,但均低于欧盟标准推荐值;表层水中As的浓度与pH呈显著正相关,说明pH值影响河水中As的迁移和转化;沉积物中As的浓度与总有机碳含量呈显著性正相关,说明沉积物中的As主要与总有机碳结合在一起;潜在生态风险评价结果显示,上海市河网沉积物中的As属于低生态风险。

Distribution Characteristics and Ecological Risk Assessment of As in Waters of Shanghai River Network

Fifty-three surface water and sediment samples were collected in Shanghai river network to determine the contents of As. The pollution statue of As in the sediments was evaluated using potential ecological risk index. Results showed that the contents of As in the surface waters and the sediments ranged from 0.47 to 8.84 μg·L-1 and from 3.72 to12.65 μg·g-1, respectively. The concentrations of As in the surface water was below the I standard value of surface water environmental quality in China (GB 3838-2002). As concentrations of 15 sediment samples were higher than that of the soil environmental background value of Shanghai, which were lower than the recommended value by EU. The significant positive correlation between the concentration of As and pH in the surface water indicated that pH values influenced the migration and transformation of As in the water. The concentrations of As in the sediments had significant positive correlation with total organic carbon (TOC), suggesting that As in the sediments was mainly bound with TOC. The results of potential ecological risk assessment showed that As in the sediments was in the low ecological risk in Shanghai river network.