不同环境下镉对小球藻吸收磷速率的影响

The effect of cadmium on the uptake rates of phosphorus by Chlorella vulgaris under different conditions

在人工配制的污水中进行静态模拟实验，研究了不同光照强度及不同pH值下，镉对小球藻（Chlorella vulgaris）在悬浮和固定状态下对污水中正磷酸盐的吸收速率的影响。结果表明，镉存在的情况下，在实验所设的各光照强度内，悬浮态小球藻对磷的吸收速率为4～10μg／（h·个），固定化小球藻为12～16μg／（h·个）；而相同的镉浓度下，在不同的pH范围中，悬浮态小球藻对磷的吸收速率为1．9～9．4μg／（h·个），固定化小球藻为5．7～12μg／（h·个）。在不同光照强度下，镉总体上降低了小球藻对磷的吸收速率，其中使悬浮藻普遍下降40％～60％，而固定处理使藻受镉的影响较少，至多下降10％～20％，但在个别光照强度下镉反而促进了小球藻对磷的吸收速率。不同pH值时，无论悬浮态还是固定态，镉在大多pH下使小球藻的磷吸收速率下降20％～30％，固定处理并没有减少镉的影响，同样在个别pH下镉促进了对磷的吸收。

Experiments in laboratory using simulated settled domestic wastewater were employed to study the effect of cadmium on the uptake rates of phosphorus by Chlorella vulgaris in two forms, alga entrapped in calcium alginate as algal beads（AB） and free alga（FA）, under different light intensities and different pH values. When cadmium was added, the uptake rates of phosphorus by FA and AB were 4-10μg/（h · cell） and 12 -16 μg/（h · cell）, respectively, under different light intensities and under different pH values those by FA and AB were 1.9-9.4μg/（h · cell） and 5.7-12μg/（h · cell）, respectively. Cadmium reduced the phosphorus uptake rates of the algae in most light intensities, rates of FA decreasing 40%-60% and rates of AB protected by calcium alginate decreasing 10% -20% at best. Under most pH values, inhibition of cadmium dropped 20%-30% of the phosphorus uptake rates of the algae, no matter FA or AB, calcium alginate works nothing. However, in some light intersities or pH, cadmium improved the phosphorus absorption of C. vulgaris.