Contents Of Different Media Elements In Water System Of Manaoke Gold Mining Area And Quality Evaluation

The main way for the development of water environment in mines is water system.As a pro-sulphur(copper)element,gold is associated with a large amount of elements such as Hg,Zn,Cd,As,etc.,to ascertain the distribution law and migration and transformation behavior of different media elements in the surrounding water system of gold mining areas,and to treat the mining environment and regional water environment pollution.Prevention is of great significance.The paper is based on the water system of the Maocao Gold Mine,and relies on the special research project of the Ministry of Environmental Protection of the Ministry of Environmental Protection on“the identification and pollution risk assessment of heavy metal pollution in groundwater in the southwestern mining area”to identify the overlying water,sediment,and interstitial water in the surrounding water system of the mining area.Based on the spatial distribution characteristics of the elements,combined with the characteristics and patterns of the element content on the sediment profile,the rule of migration and transformation of different elements in the mining area is discussed,and the environmental quality of sediments is evaluated.The results show that:(1)The pH of the river's overlying water in the study area is between 8.09 and8.41,which is weakly alkaline.Dissolved oxygen content of more than 5ppm,are oxygen-rich rivers,water chemistry type is mainly calcium magnesium carbonate type.(2)The contents of heavy metals in the overlying water and interstitial water at each sampling point are as follows:As>Zn>Pb>Cu>Cd.The order of the contents is the same as the order of the elements in most sediments.Except for the No.3sampling point,the heavy metal elements in the sediments are:As>Zn>Cu>Pb>Cd.The order of the same heavy metal elements in the three media is:sediment>gap water>overlying water.(3)Heavy metal elements are mainly concentrated in the middle and upper parts of interstitial water and sediments.The vertical distribution of elements between different interstitial water profiles differs,but the distribution of elements in different sediment profiles is similar,indicating that the distribution of heavy metals in the sediments in the study area is more stable than that of interstitial water,and the deposition of different sites is different.The sources of heavy metals may be the same.(4)Sediment profile The content of different particle size granular elements is roughly as follows:less than 160 mesh particle size>100 mesh-160 mesh particle size>80 mesh-100 mesh particle size>20 mesh-80 mesh particle size.The smaller the particle size is,the higher the content of heavy metal elements is.Due to the large surface area of the fine-grained sediment particles,it has a strong adsorption effect and is more conducive to element enrichment.(5)In most sampling sites,Cd is mainly in the form of acid-soluble state;Pb is mainly in the reduced state at the second sampling point and the fourth sampling point;in addition to Cd and Pb,the rest of the elements are mainly in the residue state.The order from high to low is residue,reducible,oxidizable and acid-soluble.(6)Correlation analysis showed that K,Na,and Cl~-in the overlying water are both well correlated,and As has strong correlation with other elements.Interstitial water and sediments show Zn and As in other elements.More significant correlation.In addition to lead,the correlation between overlying water and interstitial water is significant,and it has a good correlation.(7)The Dashegougou tributary flows through the mining area.The reach of the river section is greatly affected by mining activities.The content of heavy metal elements in the sediment is high in the sampling point,and the migration of elements in the surface sediments of each heavy metal element is relatively large.It is easier to migrate from sediments to interstitial water.With increasing depth,the mobility decreases first and then increases.At the bottom,the sediments show greater mobility.The upper and lower reaches of the Heihe River are relatively less affected by mining,and the migration of each element is not obvious.The content of elements in the interstitial water is often higher than the content of elements in the overlying water.If there is a concentration difference,the elements will diffuse from the interstitial water to the overlying water.(8)The geological accumulation index method shows that the Dashuigou tributary flowing from the mining area and the downstream of the tributary that meets Heihe River are both subject to As,Cd pollution to varying degrees,and the pollution level is from none to medium to extremely strong,among which As The degree of pollution at the junction of the Dashi'ergou tributary and the Heihe River reaches a strong level.The pollution level in the lower reaches of Heihe River is medium-strong.Except for the upper reaches of the Heihe River,Cd has moderate pollution in other river basins in the two rivers,so the mine discharges Wastewater is the main reason for the increase of As and Cd in the water content of the mining area.The potential ecological hazard index shows that the Dashuigou tributary is a strong-strong potential ecological hazard,and the intersection with the Heihe River is a slight-strong potential ecological hazard.The upper and lower reaches of the Heihe River is a slight ecological hazard.