制药直排废水和处理后废水对不同营养级别水生生物的毒性

以沈阳市某制药厂制药废水为研究对象,比较制药废水对不同营养级别水生生物的毒性效应,并评估水处理过程对毒性的削减效率。结果表明,制药直排废水和处理过程中各工艺出水对斑马鱼、大型蚤的毒性单位(TU)在1.2~2.9,对斜生栅藻、发光细菌无明显生长抑制和发光抑制效应;进水、水解和好氧过程的草履虫毒性TU在1.2~1.5。生物对制药废水毒性反应的灵敏性从高到低依次为斑马鱼、大型蚤、草履虫、明亮发光杆菌和斜生栅藻。该制药废水经水解酸化-好氧法处理后,水质达到《化学合成类制药工业水污染物排放标准》,但出水仍对大型蚤和斑马鱼产生急性毒性作用。理化指标(COD、BOD_5、NH_3-N)与毒性指标值无显著相关性,毒性去除率低于理化指标去除率。制药废水的毒性随生物营养级别升高而增强,表明其对高等生物具有潜在危害。

Toxic effects of the pharmaceutical sewage pre-and-post treatment on the survival of the aquatic organisms at different trophic levels

The present study aims to evaluate the potential hazardous effects that may be caused by the discharge of the pharmaceutical sewage.For this purpose,we have made evaluation activities and compared the toxic effects of such sewage on different aquatic organisms,such as bacteria,like Photobacterium phosphoreum,phytoplankton,such as Scenedesmus obliquus,zooplankton,such as Paramecium caudatums and Daphnia magna),as well as fish,e.g.Denio rerio in hoping to reduce the toxic effects throughout the treating process.The results of our experiments have shown that the toxicity unit (TU) of the pharmaceutical sewage has still been ranging in an ascending order of 1.2-2.9 to Denio rerio and Daphnia magna.On the other hand,no significant adverse effects have been found on Scenedesmus obliquus and Photobacterium phosphoreum.We have also found that the influents and the effluents from the hydrolysis and aerobic process may both result in lethality effect on the fish Paramecium caudatums,with TU values being at a level between 1.2-1.5.As to the sensitivity of the organisms under study proves to follow a descending order:Denio rerio ＞ Daphnia magna ＞ Paramecium caudatums ＞ Photobacterium phosphoreum and Scenedesmus obliquus.After being treated through the hydrolytic acidificationaerobic process,it can be found that the physicochemical indexes of the effluents can be made to come up to the discharge standard given in the "Chemical Synthetic Pharmaceutical Industrial Water Pollutants".The removal rate of the physiochemical indexes can be made to reach over 80％.Nevertheless,the effluents after being treated still remain acutely toxic on Daphnia magna and Denio rerio,with the said testing unit above 1.0,though the physiochemical indexes,including those of COD,BOD5 and NH3-N,may not indicate obvious correlation with the toxicity indexes.Besides,the toxicity removing rate proves to range between 44％ and 50％,much lower than the reduced rate in the physicochemical indexes,which tends to show that the toxicity of the pharmaceutical sewage has been enhanced with the increasing trophic levels of the tested organisms,thus reminding us of the potential adverse effect of the pharmaceutical sewage on the organisms at higher trophic levels.The results of the present study imply that further treatment of the pharmaceutical sewage remains necessary to reduce the toxicity of the pharmaceutical sewage more thoroughly.Along with it,it is also recommended to use more comprehensive toxic indictors to demonstrate more effectively the physicochemical indicating parameters so as to produce a more comprehensive safety evaluation for such sewage.