闽江流域表层沉积物硫化物及重金属生物毒性研究

Acid-volatile sulfide and heavy metals biotoxicity in surface sediments of Minjiang River

根据2012—2013年福建省闽江流域富屯溪、建溪和沙溪等支流以及干流7个站位表层沉积物调查数据,对硫化物(AVS)、有机碳及重金属(SEM)等物质进行了研究。结果表明,各站位硫化物两年平均含量在0.461 0~1.814 0μmol·g^(-1)之间,有机碳平均含量在0.76%~1.51%之间,尤溪S5站位硫化物含量明显高于其他站位,与此对应有机碳含量也较高,这与沿岸人类活动的强度有关;闽江干流S7站位硫化物含量最低,主要受水动力特征影响。各站位沉积物重金属(Cu、Pb、Cd、Hg和As)含量基本呈现Cu>Pb>As>Hg>Cd的趋势,其中Cu和Pb是主要污染重金属。SEM平均含量在0.47~3.58μmol·g^(-1)之间,金溪S2、古田溪S6站位SEM/AVS(摩尔比值)小于1,重金属潜在生态危害风险较小;其他站位SEM/AVS大于1,生物有效性高,具有潜在的毒性效应。与水体沉积物中金属元素对底栖生物产生毒性效应的阈值比较,单个重金属中Pb和Cd可能产生的生物有效性高于Cu,具有对底栖生物产生毒性效应的潜力。

Based on the data from seven sampling stations of surface sediments in 2012 and 2013,the acid volatile sulfide( AVS),total organic carbon and heavy metals in Minjiang River basin were studied. The results indicated that the average concentrations of acid volatile sulfide ranged from 0. 461 0 ~ 1. 814 0 μmol·g^(-1),the average contents of total organic carbon varied between 0. 76% ~ 1. 51%. The contents of acid volatile sulfide and corresponding total organic carbon in S5 station of Youxi were significantly higher than that in other stations due to the influence from human activity. In comparison,the content of acid volatile sulfide in S7 station of Minjiang main stream was the lowest,which was mainly affected by hydrodynamic characteristics. The content and variation of acid volatile sulfide were affected by many factors,so the regularity of spatial distribution was not significant. It was found that the metal concentrations were in the order of Cu > Pb > As > Hg >Cd. Among heavy metals, Cu and Pb were the dominating species. The simultaneous extracted metals( SEM) average values ranged from 0. 47 ~ 3. 58 μmol·g^(-1). By comparing the ratio of SEM to AVS,the values of all stations were greater than 1 except S2 and S6,which had high bioavailability and potential biotoxicity. Compared with the threshold of toxic effects of metal elements in water sediments on benthic organisms,the bio-availability of Pb and Cd was higher than that of Cu in the single heavy metal,which had the potential to produce toxic effect on benthic organisms.