| Coal is one of the energy of people's production and living.The exploitation of coal has a certain impact on the surrounding ecological environment,especially that heavy metals stored in natural form released into the surface environm ent and pose a threat to the environmental and human health risks of the surrounding e nvironment.Therefore,it is of great significance for the sustainable development of the region,the control of pollutants,the ecological health risks and the prevention and control of diseases to study the heavy metal pollution,health risks and the environmental migration of heavy metals in the energy development zones.This study is maily conducted the research and evaluation of the amount,spatial distribution,the feature of migration and accumulation,environmental pollution assessment and population health risk of heavy metals among multi-media environment in the typical energy development area bordering the southern part of Inner Mongolia Autonomous Region and the northern part of Shaanxi province.The surface dust,coal gangue,typical plants,surface water and groundwater were taken as the research medium and emoloying the methods of spatial analysis,multivariate statistical analysis,pollution load index and population health risk assessment model were used to study.It also analyses the difficulty degree of migration from gangue to different medias of lead and features of its metrological characteristics by making ratio of the amount of heavy metals in different mediums to it in gangue.The main conclusions are as follows:(1)The average concentration of heavy metals Hg,Cd,Co,Sr,and Ba elements in the area of 2015 and 2016 in the typical energy development area bordering the southern part of Inner Mongolia Autonomous Region and the northern part of Shaanxi province exceeds the soil background value of the Shaanxi province,but the amount of heavy metals in 2016 are low because of the heavy rainfall.The Cr-V,Cr-Ti,Cr-Ni,Cr-Cu,Cr-Zn,Cu-Zn,Zn-Ni and so on in dust have a significant positive correlation and the source of them may be the same.There are the maximum value of the amount of heavy-metal elements around the small and medium-sized coal mines and its pollution load index of heavy metal elements and carcinogenic and non-carcinogenic risk value are higher than other places,therefore,the local authorities ought to put their concentration on the pollution degree of heavy metals around the small and medium-sized coal mines.As,Cr and Ni are the main elements of carcinogenic risk to children,while Cr and Ni are the main elements of carcinogenic risk to adults,and children are more sensitive to heavy metal pollution.It is judged that heavy metals in dust may migrate mainly from coal gangue by analyzing the relationship between dust and the amount of heavy metal in coal gangue.(2)There is a certain correlation between heavy metal Cr and Cu,As and Cd in regional dominant plant leaves(Populus alba),and the spatial distribution of As and Cd,Cr and Cu are similar,and the resource of them may be the same.Most of their extremums appear in the surrounding arae of small and medium-sized coal mines,which indicates that industrial activities in the mining area are one of the reasons for the high content of heavy metals in the plant leaves.The average enrichment coefficient of Cd in plant leaves is more than 1,and the enrichment coefficients of the other six kinds of toxicity heavy metal elements are less than 1,therefore,the enrichment degree of the other six elements is not high.(3)The quality of the surface water in the energy development area is poor and it only meets the Class IV water standards of GB383 8-2002 and can not be used as source water,the concentrated water source of drinking water and the water area with human contact.The ammonia nitrogen value in the groundwater exceeds the standard value of GB/T14848-93 Class ?,and it can be only used for agriculture and partly used for industry and can not be used as centralized sources of water supply.In the study area,As,Cr and Cd are the primary risk factors of non-carcinogenic health risk,and the relevant decision-making departments and environmental protection departments should attach great importance to it(4)There is a significant positive correlation between some heavy metals in the dust and coal gangue,and the amount of Cd and Ni in plant leaves are positively correlated with the amount of Hg and Cd in coal gangue respectively,therefore,their sources are the the same.As,Cd,Hg,Pb in coal gangue can more easily migrate to dust for accumulation and then they may migrate to the plant leaves. |
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