Acute Toxicity Study Of Screening Of Sensitive Species Fish In The Paper Mill Industry Wastewater

For the past few years, more and more emergent water Pollution accidents happened, the safety of drinking water and source water area are inereasly concerned. Therefore, it is important to control of the water pollution, which is the prerequisite to achieving realtime online monitoring and evaluating water quality precisely.The toxic effects of polluted water on fish could relect the condition of water pollution, and it is helpful to make the risk assessment of pollution water for human being. Using fish to monitor water pollution would supplement the routine water monitoring.First,six fish species, Brachydanio rerio(zebrafish),Oryzias latipes (medaka),puntius tetrazon,Hyphessobrycon,Carassius auratus were choosen as target species for evaluating the toxic effects of papermaking wastewater. zebrafish and medaka were proved to be ideal fish species for the toxicity evaluation of the paper mill industry wastewater, which based on the process of screening targeted fish and pre-acute toxicity test. Testing methods for industrial wastewater—fish acute toxicty using zebrafish and medaka, both of the screening of sensitive species fish, were applied to monitoring the wastewater form the paper mill industry, which observed the behavior of fish.Sencond,Toxicity rank of wastewater was evaluated based on it. Last, the single toxicity of LAS on sensitive species fish were tested. The result showed that:1. The effects of paper mill industry wastewater on the acute toxicity of zebrafish and medaka showed that the wastewater of high toxic on them, the effects of papermaking wastewater on the acute toxicity of Brachydanio rerio and Oryzias latipes were studied. The results showed that the 24h LC50 of Brachydanio rerio,Oryzias latipes stressed by papermaking wastewater were 40.10% and 49.84%.Then,the 48h LC50 of Brachydanio rerio, Oryzias latipes stressed by papermaking wastewater were 33.74% and 45.71%, Meanwhile, the 72 h LC50 of them stressed by papermaking wastewater were 33.25% and 42.94%,beyond that the 96h LC50 of Brachydanio rerio, Oryzias latipes stressed by papermaking wastewater were 32.10% and 40.07% respectively, which showed that they had the correlation effect which increased with the time prolonging. The effects of papermaking wastewater on aquatic animals were dominated by Oryzias latipes, followed by Brachydanio rerio and in order of ranking. It can be seen in the test that the sensitivity of Brachydanio rerio are much greater than Oryzias latipes on the toxicity effects of papermaking wastewater.2. Acute toxicity were tested of two common fish species showed that the influence of surrounding formed by the Tua of both were higher than 0.3, between 2 and 10 Tua. The acute oral toxicity degree of paper mill industry wastewater on fishes was medium toxic according the Toxicity Rank of wastewater.3. The effects of LAS on the acute toxicity of zebrafish and medaka showed that the LAS of high toxic on them, The LC50 of LAS after 24h,48h,72h and 96h and zebrafish safety concentration were 7.31,6.79,6.67 and 6.30 mg/L, and that of medaka were 9.35,9.10,8.93 and 8.58 mg/L, which showed that they had the correlation effect which increased with the time prolonging.