Environmental Quality Assessment Of Collapse Pond Water In Sudong Coal Mining Area

The collapse pond is a special surface water area and plays an important role in the mining area ecology.At present,there are many ways to use of collapse ponds,such as water supply,fish farming,and agricultural irrigation.At the same time,it is also a gathering place of surface runoff.Beset by the special environment in which the collapse ponds are located,they had to face with various organic and inorganic pollution,the change trend of water quality is of great concern.This paper selected the collapse ponds in different formation periods in Sudong mining area as the research object.Through the initial investigation,sampling and testing.The chemical characteristics,heavy metal content changes were analyzed,health risk assessment of the collapse ponds were evaluation,and the water quality of the collapse ponds was comprehensively evaluated.The main research results were as follows:?1?The changes of hydrochemical characteristics of seasons were showed that the change trend of main ions in the Luling pond?formed about 50 years?was relatively stable and less affected by the external environment.The change trend of Zhuxianzhuang ponds?formed about 25³5 years?was unstable,it was greatly affected by the environment,and the change rule was not obvious.It indicated that the main ions in collapse ponds had cumulative effect and stability with the increase of formation time,and were less affected by the environment.?2?The water chemical types of three collapse ponds were classified,the results indicated that the hydro-chemical type in Luling pond and Zhuxianzhuang 1#pond was HCO₃-Na-Mg,and the type in Zhuxianzhuang 2#pond was SO₄-Na-Mg-Ca.The types were same to the shallow groundwater in the area.It was indicated the content of anion and cation in the collapse ponds of Sudong mining area was mainly from the recharge of shallow groundwater,the shallow groundwater determined the hydrochemical type of the collapse pond in the area to some extent.And the result of multivariate statistics analysis showed that the content change of pH?TDS?EC?Cl^-?SO₄^2-?HCO₃^-is affected by the pollution of coal gangue and agricultural non-point source,Na⁺?K⁺mainly came from ion exchange,and Ca²⁺?Mg²⁺was related to the recharge of shallow groundwater.?3?The results of heavy metal content analysis showed that the average values of Cd,Cu,As and Ni in the collapse ponds of the Sudong mining area were 2.6,1.4,6.1and 2.1 times of the same heavy metals of surface water,respectively,which exceeded the background value of surface water.The coefficient of variation of Pb and Zn was greater than 30%.?4?The results of health risk assessment showed that the health risk of Cr,Cd and As of chemical carcinogens was 8.65×10^-5,2.32×10^-66 and 7.89×10^-5,respectively,the health risk of Cr and As were above 5 x 10^-6,which indicated that Cr and As was a potential hazard for people.The risk of health risk of Cu,Ni,Zn and Pb of non-chemical carcinogens was small,and the order of magnitude was4.68×10^-138.68×10^-11.?5?Based on the analysis of the grid sampling results of collapse pond,the environmental influence mechanism of Luling pond of TN,TP and other index were revealed.The eutrophication degree and irrgationwater were evaluated by fuzzy comprehensive evaluation and SAR,%Na.Figure[19]table[12]reference[78]...