Analysis And Evaluation Of Heavy Metal Pollution In Water Body Of Coal Mining Subsidence Area In Panyi Coal Mine

Waterlogged area in coal field is of great importance for the local environment,sustainable development and healthy of local residence.In this paper,waterlogged area in Panyi Coal Mine of Huainan City,Anhui Province is taken as the research area and the heavy metal pollution in the research waterbody is studied.In the whole study area,14 representative sampling sites were set up,and the contents of Cu,Pb,Zn,Cd,Cr,Fe in the four seasons were tested and the inverse distance weighted interpolation method was used to analyze distribution of heavy metal concentration in the waterlogged area,and then the possible sources of all kinds of heavy metals were also analyzed.Besides that,the degree of heavy metals pollution in the study area was evaluated by single factor index method and Nemero comprehensive index evaluation method.The health risks of heavy metals Cu,Pb,Zn,Cd,Cr and Fe in the study area were evaluated by the health risk assessment model recommended by the USEPA as well.Based on the above research,the following conclusions were made:(1)Through the analysis of the concentration of heavy metals in the waterlogged area,the contents of heavy metals Cu,Pb,Zn,Cd and Cr did not exceed the national standard of class I water in four seasons;the Fe content in the spring and surmmer did not exceed the national Class I water standards,but Fe content in the fell and winter are more than the nationai V class water standards.The spatial distribution of heavy metal content in water is as follows:the content of heavy metals in the study area was high in the West and low in the East,and the seasons were basically the same,and the high concentration area was mainly concentrated in the vicinity of 4 point and 5 point.The main pollution of the subsided water area may be due to the discharge of the sewage from the Panyi Mine in the upper reaches of the Nihe River,the leaching action of coal gangue and the ash storage yard on the West Bank of the collapse area and the surrounding agricultural production activities.The seasonal variation results showed that the contents of heavy metals Cu,Cd and Cr were higher in spring,and the content of Pb,Zn and Fe in winter was higher,and the content of heavy metals in summer was lower.The minimum concentration of heavy metals in four seasons is in summer,and the average maximum is different in each season.The average concentration of heavy metals in the year was Fe>Zn>Cr>Cu>Pb>Cd.(2)The pollution degree of heavy metals in the study area was evaluated by single factor index evaluation method and Nemero comprehensive index evaluation method,and the results of the two methods were basically the same.The water in the four seasons was not polluted by heavy metals Cu,Pb,Zn,Cd,Cr.However,the pollution status of Fe was different in the four seasons,the water in the study area in spring and summer was not polluted by Fe,but in the autumn and winter,it was polluted by Fe.,(3)According to the health risk assessment model recommended by USEPA,the health risk of heavy metals Cu,Pb,Zn,Cd,Cr and Fe in the study area were evaluated.According to the criteria recommended by the Ministry of Environmental Protection,the results of the evaluation showed that all of the carcinogenic risk caused by carcinogens was significant,all non-carcinogenic substances caused by non-carcinogenic health risk is not obvious.Total health risk caused by All carcinogenic and non carcinogenic substances is exist.The overall health risk of the study area is mainly caused by carcinogenic risk,and the carcinogenic risk is mainly caused by Cr.