松花江沉积物汞的新变化:分布、演化与现状及潜在生态风险评估

分析了第二松花江中下游和松花江干流表层沉积物中总汞的含量水平和分布规律,同期采集了牡丹江、黑龙江沉积物作为对照,并采用地累积指数法以及潜在生态风险指数法,初步评价了松花江沉积物中汞的污染状况和潜在的生态风险.结果表明,松花江10个断面沉积物总汞含量范围0.029~1.317 mg·kg~(-1),均值0.183 mg·kg~(-1).第二松花江3个典型断面沉积物总汞含量均显著高于松花江干流的7个典型断面(P0.05).地累积指数(Igeo)及潜在生态风险指数(Er)表明第二松花江3个典型断面沉积物汞污染程度为偏中度至重度污染,存在高度生态风险;松花江干流7个典型断面为轻度污染,具有较高生态风险.近10年松花江沉积物汞含量变化及空间分布结果显示,现阶段第二松花江沉积物汞含量有所下降,但松花江干流个别江段沉积物汞含量有所上升,应引起重视.

Changes of total mercury in sediments from Songhua River:distribution, evolution and potential ecological risk

The occurrence and accumulation of total mercury (T-Hg) in sediments collected from the Secondary (SSR) and the main stream of the Songhua River (SR) were analyzed in this study. Meanwhile, samples collected from Mudanjiang and Heilongjiang River were employed as control, and the potential ecological risks of mercury were calculated and assessed using index of geoaccumulation (I_geo) and potential ecological risk assessment method (E_r). The results showed that the T-Hg concentrations in sediments at ten sections of the river ranging from 0.029~1.317 mg·kg^-1 with mean concentration of 0.183 mg·kg^-1. T-Hg concentrations in sediments at three typical segments of SSR were all significantly higher than those seven segments of SR (P<0.05). The I_geo and E_r indexs revealed that the T-Hg pollution levels in SSR were moderate to severe with high ecological risk, while the pollution levels in SR were mild with lower ecological risk. Comparison of monitoring results in recentten years indicated that although T-Hg pollution levels at SSR declined, certain sections of SR increased, which needed more attention.