樟湖库湾网箱养殖区表层沉积物中AVS-SEM研究

    Study of AVS-SEM in surface sediments in cage farming of Zhanghu reservoir bay, Fujian Province

    • 摘要: 为评价水库网箱养殖区表层沉积物重金属的潜在生态风险,在水口水库樟湖库湾采集5个站位的表层沉积物,对其酸可挥发性硫化物(AVS)和同步提取的重金属(SEM)进行了研究。结果表明,AVS含量范围在0.57~2.13 μmol·g-1之间,SEM含量范围在1.66~6.35 μmol·g-1之间,Zn、Cr、Cu是主要重金属,占SEM总量超过80%。SEM/AVS年平均值在1.65~9.11之间,Cr不列入计算则为1.42~7.75,(SEM-AVS)值基本小于5,AVS对重金属的束缚有重要影响,表层沉积物重金属尚不会对底栖生物产生明显毒性。就单个重金属而言,Pb可能产生的生物毒性最高。网箱养殖需对硫化物中重金属再次释放及生成H2S的潜在性危害提高警惕。

       

      Abstract: In order to investigate the potential ecological risks of heavy metals at cage farming in surface sediments, 5 samples were collected from Zhanghu reservoir bay in Shuikou reservoir and the acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) were studied. The results indicated that the AVS concentrations ranged from 0.57-2.13 μmol·g-1, and the SEM concentrations ranged from 1.66-6.35 μmol·g-1. Among heavy metals, Zn, Cr and Cu were the dominating metals, accounting for over 80% of SEM. By comparing the ratio of SEM to AVS, the values of annual average were ranged from 1.65-9.11. If Cr was not included in the calculation, the values were ranged from 1.42-7.75, and the value of (SEM-AVS) were mainly smaller than 5. These indicated that heavy metals were associated with the AVS phase in the sediments, while metals in surface sediments could not cause toxicity to benthic organism. Compared with the threshold of toxic effects, the most toxic metal was Pb in terms of individual heavy metals. According to the present study, the potential toxic effects of heavy metal release and hydrogen sulfide (H2S) production from sulfides on cage aquaculture should be on the alert.

       

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