Research Of Water Quality Criteria For Nonylphenol Based On Multi Effect Endpoints

As a typical endocrine disrupting compounds,nonylphenol（NP）with low concentrations can directly affect the growth of many aquatic organism.Over the past more than two decades,a majority of studies have validated that NP presented widely in the various environment medias,in particular,which can worsen the water quality to a great extent.As yet,water quality criteria（WQC）with respect to nonylphenol pollution have not been established in China.Therefore,it is of very importance and emergency to conduct a systemic study of water quality criteria on NP based on the characteristics of biota in China.Here,the WQC of nonylphenol based on different endpoints was derived from an analysis of species sensitivity distribution.This study not only provide useful reference to establish the water quality standard of EDCs pollutants,but also can serve as the theoretical basis to promulgate relevant water quality criteria by environmental ministry,additionally,it is also meaningful to the prevention and control of NP freshwater pollution.The main results are as follows:On the basis of characteristics of freshwater biota in China,the screening principles of toxicity data and the reliability evaluation system of toxicity data were constructed.Regarding the selection of toxic data for EDCS such as NP,the present study pointed out a general principle with a wide species range of three families and eight categories,also highlighted the characteristics of freshwater biota and highly sensitive species in China.The study can focus on the NP acute water quality criteria aimed at the invertebrates such as the water fleas,especially for the carp,crucian carp and the rare carp.For the sensitivity distribution of species,owing to its good robustness,the log-logistic function is proved to be the optimal distribution.On the basis of an analysis of minimum sample size,a stable value of HC₅ can be achieved when the amount of data exceed twelve.To analyze the multi effect endpoint,a series of criteria values were observed:the value of acute toxicity is 23.55μg/L,while the corresponding value of the mixing effect is 1.42μg/L;the values of reproduction（vertebrates）,reproduction（invertebrate）,growth/development,and survival are 0.53μg/L,1.41μg/L,1.67μg/L,9.53μg/L,respectively.As a result,the values of 1.42μg/L and 0.53μg/L could be recommended as a chronic criteria value of NP in China,a reference criteria value for rare aquatic habitat and fish spawning ground,respectively.Among 45 surface fresh water in China,the concentration of NP ranged from nd³2.85μg/L,with an average value of 1.397μg/L.The range of risk quotient of NP is 0.014⁶.015,most of surface water（87.5%）are not high risk ones.By the probability risk assessment method,it can be concluded that the level of NP pollution in the surface water in China pose little influence on the growth/development of the organisms and the reproduction of the invertebrates,which has no threat to their survival,but it is harmful to the reproductive health of vertebrates to a certain degree.