铜对缘管浒苔（Enteromorpha linza）的毒性效应

TOXIC EFFECT OF COPPER ON BENTHIC GREEN AIGAE IN THE YELLOW SEA

研究了铜对缘管浒苔（Ｅｎｔｅｒｏｍｏｒｐｈａｌｉｎｚａ）的毒性效应，试验了不同的配合剂对铜的毒性效应及累积量的影响。结果发现，铜对缘管浒苔的毒性效应阈值为０．１０ｍｇ／Ｌ；０．５０ｍｇ／ＬＣｕ￣（２＋）可使缘管浒苔迅速死亡，培养９６ｈ后光合作用强度下降为零。ＥＤＴＡ可抑制铜在藻体中的累积，缓解毒性；８－羟基喹啉则促进铜在藻体中的累积，加刷了毒性。和铜污染的培养介质短期接触（＜１ｍ后，加入足量ＥＤＴＡ，藻体生长和对照组相当，较长时间接触（＞４ｈ）后，ＥＤ－ＴＡ不能使藻恢复生长。结合ＥＤＴＡ“洗脱”实验提出，Ｃｕ￣（２＋）可能首先经离子交换机制结合于藻体表面，之后，才逐步向细胞内转移。

Interactions between dissolved Cu and one common benthic green algae,Enteromorpha Linza were studied in the laboratory,including the influence of chelators on Cu accumulation and toxicity of Cu on the growth of E. Linza The results show that the threshold concentration of cu￣(2+) on the toxicity of E. Linza is ca. 0.10mg/L in solutions;0.50mg/L of Cu in seawater may limit the growth of E. Linza and the photosynthesis intensity drops to zero when the algae is cultured for four days. EDTA may inhibit the accumulation of Cu￣(2+) in algae,hence decrease the toxicity of Cu whereas 8-hydroxy quinoline fa-clitates the absorption of Cu by E. Linza and increases toxicity of Cu. If the E. Linza is cultured in seawater with 0.20mg/L Cu￣(2+) , EDTA may release the algae from pollution when the culture is less than one kour, and the E. Linza growth rate is the same as that of reference sample(algae cultured free of Cu). Longer culture(e. g. 4h)may induce irreversable effect and addition of EDTA can not decrease the toxicity of Cu to E. Linza. This experiment,in combina-tion with EDTA leaching study, indicates that toxicity of Cu on E. Linza can be described by two step models: ion exchange which introduces Cu￣(2+) to the surface of E. Linza and accumulation of Cu in E. Linza which may result in toxic effects.