The Geochemical Characteristics And Environmentalevaluation Of Quality In Mercury Mine Area Of Guizhou Wanshan

Guizhou Wanshan District,as one of the world's largest mercury mines and the largest domestic production base of mercury,from the beginning of the Qin Dynasty mercury mining and smelting has been up to 600 years,has a long history,large-scale mining left a lot of historyproblem.The whole mine smelting mercury ore slag and waste rock piled up,and the point of a wide range of mercury mine slag,mercury-containing waste gas and waste water are all directly discharged into the natural environment,a serious threat to the ecological environment and human health.Based on the investigation and research on the hydrogeological environment of the typical mercury mine in Wanshan,Guizhou Province,this paper explores the soil geology of the mining area by using the method of environmental geochemistry,which is based on the environmental protection and public welfare industry research project of China Environmental Protection Department.The atmospheric dust and the main crops in the heavy metal content and characteristics,and simulated rain on the slag leaching experiments,obtained slag leaching solution of heavy metal content characteristics,according to the human and the surrounding environment by the degree of heavy metal pollution risk,close to mountains mine after the pit integrated environmental management evaluation of the situation.The following results were achieved through research:1?Karst study area is not developed to the main superficial fissure,there is no regional karst pipes,underground river.Water Enrichment of Water weaker,smaller underground water,ground water is not abundant.Groundwater runoff with a short route,the nearest excretion characteristics.To watershed,surface river basin boundaries as hydrogeological units,or high ground water from the watershed to the low-lying parts?valley?parts of the bus,and then into several rivers.Hydro-geophysical exploration found six bedrock deep study area has low resistivity anomaly position,presumably due to corrosion fracture zone.2?The average contents of Cr,Ni,Cu,Zn,As,Cd,Pb and Hg in the soil were 73.08,50.01,40.88,2.57,45.53,1.50,53.44 and 35.10,respectively.The results showed that the average contents of Ni,As,Cd and Hg were more than Grade 2,and the Hg elements exceeded the most serious,and the average content exceeded 70 times,and the average The maximum content of Hg elements in the smelter was 81.46 mg / kg,which was 163 times higher than that of the secondary standard,which was the highest in the whole study area.Secondly,the average content of Cd elements exceeded 5 times,among which the Cd element in the tail pond area was 5.25 mg / kg,exceeding 17.5 times.3?The pH value of the vertical section of the smelter was weakly alkaline,and the change of the heavy metal elements decreased with the increase of the depth,and the obvious enrichment was observed at the top level.The pH value of the tailings was reduced by the slag The content of heavy metals in the range of 0 60 cm,the content of heavy metals gradually increased,reached the maximum at 60 cm,then 60 100 cm,the content of heavy metals increased with depth,the elements Content to a minimum,the profile has a middle enrichment.4?In the study area,the contents of Hg and Cd in the two samples were significantly higher than those in the samples.The contents of Hg and Cd in the soil were mainly affected by the contents of Hg and Cd in the soil.The Pb,The content of Pb in the corresponding soil did not exceed the secondary standard of soil quality environment,and it was deduced that the three kinds of plant samples had strong absorption ability to Pb element.5?The contents of Zn,Cd and Hg in the tailings reservoir were the most serious,and the contents of As and Hg were higher than those of the 18th-stage tailings reservoir.The Hg and Zn elements in the smelter area exceeded the standard.In contrast,Wan Shanzhen regional atmospheric dust pollution is relatively light.Overall,the study area of atmospheric dust in the Hg elements is excessive,need to strengthen the study area of dust and dust control,to protect the health and safety of the human body.6?The water content of the river water in the Wanshan Mercury Mine is between 7.98 and 8.71 under the action of water rock reaction and slag leaching.Cation is predominantly Ca²⁺,followed by Mg²⁺,which is consistent with the main characteristics of water composition in carbonate rocks.Anions to SO42-,HCO3-based,SO42-concentration in the Dashui River tailings reservoir waters the highest,suggesting that SO42-mainly from the tailings leaching.Metal,Cu,Pb,Zn,Mn,Fe,Cd and As did not exceed the standard of environmental quality standards for surface water except Hg.Hg elements in Dashui River waters exceeded,may come from the tailings of the tailings leaching.The correlation between F-,SO42-,Cl-,NO3,K+,Na +,Ca²⁺ and heavy metal elements Hg,Mn and Cd is better.7?The leaching rate of heavy metals in five samples of the study area is the highest of Cr element.When pH = 7,the leaching rate of each heavy metal element is the highest.Through the leaching trend analysis,As and Pb elements are more easily leached in acidic environment,Cr element is more likely to migrate and leach under neutral conditions.In addition,the leaching of Cr in the leaching solution increases with time,which is different from other elements.8?The environmental assessment of surface water,atmospheric dust and plant samples in the study area was carried out by using the single factor index method and potential ecological risk index method.The Hg elements in the upper reaches of the Dashui River were highly polluted by the potential ecological risk coefficient analysis.The potential ecological risk coefficient of single heavy metal element in maize is a slight pollution,and the four seasons are strong pollution,while pepper is extremely polluted.All Hg elements in atmospheric dust of the potential ecological risk coefficient of more than 320,are highly polluting.The environmental pollution of the surface soil in the study area is strongly polluted.From the regional point of view,the pollution load index of soil in Wanshan Town is very strong pollution,and soil pollution load index is strong pollution in the other five regional.