Updated Study Of Water Quality Criterion Of Pentachlorophenol For Protection Of Aquatic Organism In Tai Lake

The water environment in Tai lake has been seriously contaminated, with almost all the water bodies suffering from pollutions at different extents. Especially in recent years, with the rapid development of economy, water pollution accidents occur regularly. Currently the water criterion research on Tai lake has just started, and the previously standards of water pollutants are mainly based on the national standard of water quality, which are unsuitable for aquatic organisms and environmental characteristics in Tai lake. The criterion studies regarding water quality play a key role in the control and surveillance over the water pollution in Tai lake. Pentachlorophenol, ubiquitous in the surface water in China, is a typical priority control pollutant with complex environmental behaviors and toxic effects. Therefore, in the present study, pentachlorophenol was employed as an example to explore a suitable calibration path in protecting water quality criterion of aquatic organisms in this basin, which might lay a solid foundation for calibration researches on water quality criterion.Since aquatic organisms in different basins have a varying tolerance for pentachlorophenol, in this study, the toxicity test data of pentachlorophenol was introduced complementally in nine species of typical aquatic organisms among four phyla in Tai lake (Limnodrilus hoffmeisteri, Daphnia magna, Neocaridina denticulate, Scenedesmus obliquus, Rana chensinensis, Pelteobagrus fulvidraco, Hypophthalmichthy smolit, Hypophthalmichthys nobilis, Ctenopharynodon idellus).Moreover, the previously pentachlorophenol toxicity data of aquatic organism species in Tai lake was obtained through the extensive literature searches using some database. Then the statistic analysis was performed to deduce the water quality criterion of aquatic organism in Tai lake with pentachlorophenol perturbation via the method of Species Sensitivity Distribution (SSD).As the compositions of aquatic organisms in different basins are quite different, the composition historical developments of phytoplankton, aquatic plants, zooplankton, benthic animals and fish were investigated, and the water quality criterion of aquatic organisms in Tai lake with the protection of pentachlorophenol was further calibrated by using Species Sensitivity Weighted Distribution (SSWD).It is known that the water environment characteristics of different basins are quite different, the toxicity tests of nine species of aquatic organisms among four phyla (Limnodrilus hoffmeisteri, Daphnia magna, Neocaridina denticulate, Scenedesmus obliquus, Rana chensinensis, eobagrus fulvidraco, Hypophthalmichthy smolitrix, Hypophthalmichthys nobilis, Ctenopharynodon idellus) were carried out with raw water, which were collected in four different points (Huangnian Bridge, Fenshui Bridge, Dapu Harbor and Chendong Harbor) of Tai lake. The water-effect ratio of this basin is 4.72.According to this result, when pH=7.8, to protect 99%,95%,90%, and 80% of aquatic organism composition in this basin of 1980s, the criteria maximum concentrations of pentachlorophenol are 23.27,94.42,178.04, and 354.24 μg/L, respectively, and the corresponding criteria continuous concentration 1.02,8.29,21.41, and 59.92 μg/L. However, in order to protect 99%,95%,90%, and 80% of aquatic organism composition in this basin of the early 21th century, the criteria maximum concentrations of pentachlorophenol are increased to 56.40,208.74,377.36, and 717.91 μg/L, respectively, and the corresponding criteria continuous concentration 7.83,44.13, 96.50, and 225.59 μg/L, respectively. Altogether, in order to restore the water quality to the state of 1980s, more strict water quality criterion is needed compared to that of protecting the current water bodies.In conclusion, through this calibration study, matrix values of water quality criterion under different pH were determined, which was with the protection of pentachlorophenol covering 99%,95%,90%, and 80% of aquatic organism composition of both 1980s and today. The findings pave new avenues for future studies of water quality criteria and standards in Tai lake.