The Mineral Occurrence State Of Arsenic In Typical Gold Mines And The Characteristics Of Arsenic Accumulation In Farmland Soil

China is rich in mineral resources,and the heavy metal pollution caused by mining activities is an important problem in environmental protection,especially arsenic pollution.The toxicity of arsenic in soil is not only related to its total amount,but also closely related to the mineral characteristics of arsenic occurrence.It is important to understand the ways of arsenic release and migration and its pollution behavior based on mineralogical information.Based on the analysis of the characteristics of arsenic minerals in the samples of the Qinglong Banbishan gold mine and its surrounding environment in Hebei province,this paper discusses the influence of arsenic gold deposits on the surrounding crops and human health,thus revealing the arsenic migration behavior and harm degree,and providing scientific basis for the investigation of environmental pollution in mining activities and the protection of farmland.The main research results of this paper are as follows:(1)The occurrence minerals of arsenic in the ore,tailings and waste rock of Banbishan gold mine in Qinglong county are mainly arsenopyrite.SEM-EDS results showed that arsenic was released during the oxidation of arsenopyrite,Raman spectroscopy revealed hematite in the oxidation zone.(2)Arsenic accumulation was obvious in the farmland soil affected by the mining activities of Banbishan gold mine.The analysis by polarized light microscope and scanning electron microscope showed that arsenic in the soil was mainly in the form of arsenopyrite,and there was no obvious oxidation of arsenopyrite.(3)Arsenic in the surrounding farmland of Banbishan gold mine is 7.2~196.2mg/kg,with an average value of 31.8 mg/kg,which is 25 mg/kg above China’s standard value of soil arsenic(GB15618-2018).Arsenic content of food crops is 0.01~0.12 mg/kg,which is lower than the standard value of China’s ministry of agriculture(NY 861-2004)As≤0.7 mg/kg.Arsenic content of vegetables is 0.04~0.42 mg/kg,which is lower than the limit of arsenic in GB 2706-2017(As≤0.5 mg/kg).The possible reason is that arsenic in the soil is mainly in the mineral form of arsenopyrite,which is relatively stable in the environment and uneasy to be enriched and transported in crops.(4)The results of human health risk assessment show that the waste rock in Banbishan gold mine has high carcinogenic risk to both adults and children,and the tailings have carcinogenic risk to children...