模拟酸雨对巢湖底泥营养盐和重金属释放及其影响

通过降低巢湖上覆水pH值以模拟限定条件的酸雨,旨在探究模拟酸雨对巢湖底泥营养盐和重金属释放的影响,以期预测酸雨或者酸性废水对湖泊生态系统稳定性的影响。结果表明:模拟酸雨过后上覆水的pH值均有回升,但强酸性模拟酸雨(pH 4.0)的恢复力较差;试验期间水体中的DO大小顺序始终为对照组试验组(pH 5.5)试验组(pH 4.0);模拟酸雨促进了底泥中氮和磷的的释放,且试验组(pH 4.0)上覆水中TN和TP含量显著高于试验组(pH 5.5)(p0.05);弱酸性模拟酸雨条件下以Fe/Al-P释放为主,强酸性模拟酸雨作用下以Ca-P释放为主;对照组的微囊藻生物量显著高于模拟酸雨组,说明模拟酸雨抑制微囊藻生长;pH值、TN、TP和Fe/Al-P均与底泥中四种主要重金属Pb、Zn、Cd和Cu含量显著相关(P0.05),说明酸雨和营养盐均是影响底泥中重金属赋存形态和释放性的重要因子。

Effects of Simulated Acid Rain on the Distribution and Transformation of Pollutants in Sediment of Lake Chaohu

The aim of this paper is to study the effects of simulated acid rain on the release of nutrient salts and heavy metals of sediment by reducing the pH value of overlying water from chaohu lake, so as to predict the effects of acid rain or acid wastewater on the stability of lake ecosystem.The simulated results showed that the pH value of the overlying water recovered after simulated acid rain, but the resilience of strongly acidic simulated acid rain (pH 4.0) was poor. During the experiment, the order of DO content in water was CK > the test group (pH 5.5) > the test group (pH 4.0). The simulated acid rain promoted the release of nitrogen and phosphorus in the sediment, and the content of TN and TP in the overlying water of the test group (pH 4.0) was significantly higher thanthe test group (pH 5.5) (P<0.05). Iron/aluminum phosphate were released mainly under weakly acidic simulated acid rain condition while calcium phosphate were released mainly understrongly acidic simulated acid rain condition. The biomass of Microcystis sp. was the largest of the control group, but not the two experimental groups, indicating that the simulated acid raincould inhibit the growth of Microcystis sp.. The pH value, TN, TP and Iron/aluminum phosphate were significantly correlated with the content of Pb, Zn, Cd and Cu, the four major heavy metals in the sediment (P<0.05), indicating that acid rain and nutrient salts were important factors affecting the occurrence and release of heavy metals in the sediment.