铜锈环棱螺对沉积物中重金属的生物积累及其与重金属赋存形态的关系

Bioaccumulation of sediment heavy metals in Bellamya aeruginosa and its relations with the metals geochemical fractions

以铜锈环棱螺(Bellamya aeruginosa)为测试生物,采用28d沉积物生物积累试验研究铜锈环棱螺对污染河流沉积物中重金属的生物积累,并探讨其与重金属赋存形态的关系.结果表明:铜锈环棱螺肝胰脏对Cd、Pb、Cu、Cr、Zn和Mn均具有较强的积累作用.不同重金属的积累量存在较大差别,Zn的积累量最多,占重金属总积累量的84.32%±4.36%,其次为Cu,占7.67%±2.84%;Pb、Cr和Mn的比例相对较少,分别为3.62%±1.84%、2.22%±1.03%和1.33%±0.15%;Cd所占比例最少,为0.83%±0.53%.肝胰脏中重金属元素之间的相关性均不显著.肝胰脏金属污染指数与沉积物污染综合指数具有显著的正相关关系,铜锈环棱螺可以作为沉积物重金属污染的监测生物.不同沉积物Cd、Cr、Zn和Mn的生物-沉积物积累因子(BSAF)具有较大的差异,Cu和Pb的BSAF比较稳定.Cd的生物积累与沉积物中Cd的可交换的与酸可溶态及可氧化态显著相关;Pb的生物积累与Pb的可还原态显著相关;Cu的生物积累与Cu的可氧化态显著相关;Mn的生物积累与Mn的可交换的与酸可溶态和可还原态显著相关;Cr和Mn的生物积累与其不同形态和总量均不相关.BSAF不宜作为衡量铜锈环棱螺对沉积物中重金属生物积累能力的指标.

A 28-day sediment bioaccumulation test was conducted to study the bioaccumulation of river sediment heavy metals in Bellamya aeruginosa, and its relations with the geochemical fractions of the metals. A higher bioaccumulation of Cd, Pb, Cu, Cr, Zn, and Mn was found in the hepatopancreas of B. aeruginosa, with the greatest accumulation of Zn （84.32%±4.36%）, followed by Cu （7.67%±2.84%）, Pb （3.62%±1.84%）, Cr （2.22%±1.03%）, Mn （1.33%±0.15%）, and Cd （0.83%±0.53%）. No significant correlations were observed between the heavy metals accumulations in B. aeruginosa hepatopancreas, but the significant positive correlation between the metals pollution index of hepatopancreas and the Nemerow pollution index of sediments suggested that B. aeruginosa could be used as a potential bioindicator for sediment heavy metals pollution. The biota-sediment accumulation factors （BSAFs） for Cd, Cr, Zn, and Mn from different sediments showed a higher variability, while the BSAFs for Cu and Pb were relatively constant. The bioaccumulation of Cd had significant correlations with exchangeable Cd, weak acid soluble Cd, and oxidizable Cd; Pb bioaccumulation had significant correlation with reducible Pb; Cu bioaccumulation had significant correlation with oxidizable Cu; while Cr and Mn bioaccumulation had no correlations with the total concentrations and geochemical fractions of the two metals. Therefore, it would be inappropriate to use the BSAF as the indicator for the bioaccumulation of heavy metals in B. aeruginosa.