Hg^（2＋）对固定化小球藻污水净化及生理特征的影响

Effects of Mercury on Sewage Purification and Physiological Characteristics of Immobilized Chlorella

利用褐藻酸钙凝胶包埋固定普通小球藻，对人工配制的含汞污水进行静态净化实验。研究了不同浓度Ｈｇ（２＋）对固定化小球藻净化污水中氨氮、正磷酸盐的效率及其４个生理指标（叶绿素ａ、光合强度、生长和过氧化物酶）的影响，并与悬浮藻对照比较。结果表明；由于小球藻的固定化增加了对Ｈｇ（２＋）毒性的抗性，０．２×１０（－６）浓度的Ｈｇ（２＋）对其净化效率无多大影响，而悬浮藻的净化效率明显下降。随着Ｈｇ（２＋）浓度的增加，；固定藻的净化效率逐渐下降，但其净化效率仍高于不含Ｈｇ（２＋）污水中悬浮藻的净化效率、且固定藻的生长、叶绿素ａ含量、光合强度和过氧化物酶活性与悬浮藻一样随Ｈｇ（２＋）浓度的增加而降低，但较悬浮藻高。

Chlorella vulgaris entrapped in an alginate gel was used to remove NH_4￣+- N and PO_4￣(-3)-P from wastewaters containing different levels of mercury (Hg￣(2+) ) in laboratory, and the effects of mercury on the removals of nutrient salts and on the physiological features such as chlorophyll-a,photosynthetical intensity, growth and peroxidase activity of the immobilized algae were examined and compared with those of free algae(control).It was found that the immobilized algae had an increased resistance to the toxicity of mercury so that a concentration of 0. 2 ×10￣(-6)Hg￣(2+)or less did not significantly affect its efficiency in removing the nutrients while allowing the free algae to have a significantly reduced efficiency in removing the nutrients. As the Hg￣(2+) concentration increased,the immobilized algae had a gradually decreasing removal of nutrients which was still higher than that of free algae in a wastewater without Hg￣(2+). Similarly, the growth,chlorophyll-a content, photosynthetical intensity and peroxidase activity of the immobilized algae decreased with increasing the Hg￣(2+) concentration but were still higher than those of free algae.