Preliminary Aquatic Life Criteria Development Of Ammonia In Qingyi River Basin

The water quality standards currently used in China have been developed with reference to water quality criteria and standards in developed countries.In recent years,in order to provide scientific basis for water quality management,some researchers have carried out researches on the water quality criteria of pollutants at the national level.However,China has a wide land and large environmental diversity in different regions.Using the national water quality criteria as a reference for the deduction of local standards will inevitably lead to inadequate protection or excessive protection.Ammonia is the main pollutant present in China's water bodies at the present stage,and also the main pollution factor in Qingyi River,a tributary of the Shaying River system in the Huai River Basin at the beginning of the study.Some scholars have been developing aquatic life criteria nationwide and in Taihu and Liaohe River basins.However,the relevant research on the aquatic life criteria of ammonia in the Huai River Basin research is not deep enough.On this basis,we carried out researches on the aquatic life criteria of ammonia in the Qingyi River Basin.Firstly,through the basic data research,the list of the existing aquatic organisms in the Qingyi River Basin has been obtained,of which the aquatic plants,zooplankton,aquatic vertebrates and benthos accounted for 59.7%,19.4%,10.6% and10.2%,respectively.In combination with the list of aquatic organisms in the Qingyi River Basin and the principles for the screening of toxicity data and transformation methods,the acute toxicity data for 26 aquatic organisms which belonged to 5phylum,18 families and chronic toxicity data for 6 aquatic organisms which belonged to 2 phylum,4 families were obtained.The data of acute toxicity were abundant,except for aquatic plants,the species of zooplankton,aquatic vertebrates and benthos accounted for 29.6%,51.9% and 18.5%,respectively.Which have great differences in the composition of aquatic organisms in the actual water bodies of the Qingyi River Basin.Based on this consideration,the SSD method is improved.There is less chronic toxicity data and a supplemental toxicity test is needed to derive a Criteria Continuous Concentration using the acute-chronic ratio.Secondly,to supplement the acute and chronic ratio data,the semi-fluid method was used to investigate the toxicity of ammonia on red carp for 96 h and 28 d.When the water temperature was 20.0? and the pH value was 7.00,the acute toxicity data for deducing the CMC of ammonia was 189.430 mg TAN/L,and the chronic toxicity data for deducing the ammonia CCC was 14.120 mg TAN/L.According to the relationship between the sensitivity of each biochemical index to ammonia stress and the dose-effect relationship with ammonia concentration,the combination of SOD,MDA and GSH index can be used to evaluate the impact of ammonia nitrogen stress on the body of red carp.Thirdly,based on the toxicity data screening and the test results,Species Sensitivity Ranking(SSR),species sensitivity distribution(SSD),and improved species sensitivity distribution(improved SSD)after considering the composition of aquatic organisms in the basin were used to determine the aquatic life criteria of ammonia in the Qingyi River Basin.It was deduced that when the water temperature was 20? and the pH was 7.0,the values of CMC of ammonia on aquatic organisms were 6.347,7.064,and 9.077 mg TAN/L,respectively,and the values of CCC were2.898,1.517 mg and 2.078 mg TAN/L,respectively.At last,combined with the results of the values of CMC and CCC.As for water quality emergency risk management,it is recommend to refer to the improved SSD derivation results,and the water quality emergency risk could be divided into four grades of ?-?,the values of which are 2.9,5.9,17.3 and 25.5,respectively.It is recommended to refer to the results of the SSR derivation during the long-term protection of aquatic life in Qingyi River.When the requirements for the protection of aquatic organisms are high,the protective concentrations in summer and non-summer are 0.1 and 0.7 mg/L,respectively.It can be a little lower at the stage of water quality improvement,and the concentrations of ammonia in summer,non-summer,andannual average are 0.4,1.2,and 1.0 mg/L,respectively.