一种评价重金属污染对大型海藻毒性效应的新方法

NEW METHOD FOR EVALUATING TOXICITY OF HEAVY METALS ON MARINE MACROALGAE

提出一种监测污染物对大型海藻毒性效应的新方法。该方法仅需将在有害环境中生长或培养的大型海藻置于一封闭的、经0．45μm膜过滤的海水体系中，在一定条件下培养1h（设白、黑二瓶），之后测定白、黑二瓶pH值共计算其差值△pH(i)，再同样测定对照组白、黑二瓶pH差值部△pH(c)，计算△pH(i)/△pH(c)，则此计算值即可用来代表相对光合作用速率，并用于评价毒性效应大小。另外，还较详尽地论证了该方法的水化学依据。

A new method for evaluating toxicity of heavy metal pollutants to mallne macroalgae was developed. Accowhng to thes method, macroalgae which lived in heavy metal conednated waters were cultUred in 250ml airtight bottle filled with 0.45μm membrane filtrated seawater for 1 hour, then pH of cultUre medium in light and black bottles were measmed. The value △pH(i)/ △pH(c), and c denote experiment and control samples respechvely) indicates the approximate relative Photosynthehc rate. It can be used to evalat toxicity of heavy metal pollutants to mallne macroalgae. Using mis mcthod, the toxicity of Cd2+ (0.0, 0.2, 1.0, 5.0, 10.0mg/ L) and Hg2+ (0.0, 0.05, 0.20, 0.50mg/ L) on Ulva pertusa Kjellm were tested and compared with the fesults obtrined from tradihonal method i.e. the dissolved oxygen methed; the results are comparale. It was found tha the 96h threshold concentrahons of Cd+ and Hg2+ on the tOxicity of Ulva pertusa Kjellm are 0.20-1.00mg/ L and 0.05-0.20mg/ L, respechvely. Using this method, the effect of CU2+ and its chelators on Enteromerpha lihza's growth were also studied. The result shows that Cu2+ has a large effect on the growth of Antermorpha linza. The growth is ichbited when the concentrahon of copper ions is higher than 0.20mg/L. The toxicity of copper was changed sighificantly with the existence of EUTA or 8-hydroxy qulnaldine in the culbe medium. The chemical speciation is an important factor affechng toxicity of heavy metals. Due to EDTA inhibits while 8-hydroxy qulnaldine enhances the absothane of copper by Entemerpha linza, so EDTA alleviates the toxicity but 8-hydroxy qulnaldine significanily exacerbares copper toxicity to Antermerpha linza. These resultS are qulte comparable to the results obtained by using weighting method. The aquatic chethestry principle of ffos method was discussed in detail.