太湖梅梁湾与五里湖沉积物活性硫和重金属分布特征及相关性研究

对太湖梅梁湾和五里湖表层及柱状沉积物中的酸性可挥发性硫化物(AVS)、同步可提取金属(SEM)及重金属总量的分布特征进行研究.分析发现,表层沉积物中的AVS与SEM具有相同的分布特征,其浓度均自河口稳定沉降区至湾(湖)心方向减小.表层沉积物中AVS/SEM<1,说明表层重金属具有潜在的生物有效性.AVS浓度在沉积深度上具有先增加后减小的趋势,且波动幅度较大,而SEM的浓度保持相对稳定.比较SEM与重金属总量得知:Cu和Ni的提取量有自表层至下层逐渐降低的趋势,表明硫结合态的Cu、Ni在逐渐增加;Pb和Zn的提取量与硫态沉积物相比较低,说明太湖AVS对Pb和Zn的控制作用较小.由AVS与活性铁的摩尔比可知,重金属在研究湖区沉积物中变化较强.

Distribution Characteristic and Correlation Relationship of Reactive Sulfur and Heavy Metals in Sediments of Meiliang Bay and Wuli Lake of Taihu Lake

The distribution characteristic of acid volatile sulfide (AVS), simultaneously extracted metals (SEM), and total metals were studied in the surface and core sediments of Meiliang Bay and Wuli Lake in Taihu Lake. It was found that there were similar distribution characteristics for AVS and SEM in surface sediments, and the concentration of AVS and SEM decreased from the steady deposition area of estuary to the centre of the bay (lake). The ratio of AVS/SEM was < 1 in the surface sediments, indicating that heavy metals in surface sediment might have potential bioavailability. The concentration of AVS increased with sediment depth, followed by decrease with large variation, while the concentration of SEM remained constant. Though comparing the concentration of SEM with total metals, it was shown that the extracted Cu and Ni decreased with sediment depth, indicating that increasing association of Cu and Ni with sulphides in deeper sediment layer, while the lower extracted ratios for Pb and Zn compared with sulfidic sediment illustrated that the AVS should not have a strong controlling on sediment Pb and Zn. From the molar ratio of AVS and reactive iron, it is known that the heavy metals were rather dynamic and active in sediments of studied sites.