Time Effect For The Study Of Monitoring Toxicity Of Sewage From Pollution Sources By Small-sized Fishes

Water plays an essential role in human society. With the rapid development of modern industry, all kinds of organic-inorganic pollutants are poured into water environment. These harmful pollutants then accumulate in water body, which makes water pollution more serious in our country. In order to decrease the pollution from industrial sewage and protect water source and water ecosystem, more concerns are paid on sewage evaluations and more bio-monitor works are being carried on.Fish is a species which live in water for whole life with a relatively perfect tissue system. Fish also extremely enjoys a feeling of toxic and harmful stimulants. Therefore, fish test is not only an important method to measure sewage toxicity, but also a common method for regulators to monitor sewage. So far, some bio-standards have been set up for fish tests, such as GB/T13267-1991, which is a standard method to test the water acute toxicity to freshwater fish; GB/T21281-2007, which is a method to determine acute toxic level of dangerous chemicals to fishes; GB/T21814-2008, which clarities the industrial acute toxicity on fish test; etc. However, both the new national standards and the traditional standards need development in order to be better used in daily life. The error from diluting and long experimental time, discounts the wide use of bio-comprehensive monitors.More effective and faster methods are needed in water-pollution source management and dealing with emergent water pollution accidents. This study carries on various acute toxic experiments on5kinds of fishes such as Hemigrammus rhodostomuss, Brachydanio rerio, Puntius tetrazona, Xiphophorus maculates and Paracherirodom innesi in various industrial sewages. After achieving LC50and TL50, the correlations between them were analyzed. The researcher took time as alternating quantity, and then determined the toxicity of the medium lethal time from combining different species of experimental fishes. This method overcomes the current one for being more accurate and faster, which satisfies the need for monitoring water-pollution source. This method contributes a lot on practicability and broadness on daily monitoring management.The main conclusions are stated as following.By experimented on the five species fish, Hemigrammus rhodostomuss, Brachydanio rerio, Puntius tetrazona, Xiphophorus maculates and Paracherirodom innesi, the Correlation Coefficient of LC50tested from new method and traditional methods are between0.85-0.95, which is significantly correlated. This indicated that, LT50is available to be used as toxicity measurement standard instead of LC50.The new method is more accurate and sensitive than the former methods, which contributes to sewage management.The assessment by the new method on electric, chemical, pharmaceutical, dyeing, electroplating, paper-making and other industries are similar with Lijun Li’s assessment got by traditional method.