Ecological risk assessment and early warning of heavy metal cumulation in the soils near the Luanchuan molybdenum polymetallic mine concentration area,Henan Province,central China

The Luanchuan molybdenum polymetallic mine concentration area is rich in mineral resources and has a long history of mining.The environmental impact of long-term mining activities cannot be ignored.It is of great significance to study the ecological risk and the accumulation trends of heavy metals in the soil of mining areas for scientific prevention and control of heavy metal pollution.Taking the Taowanbeigou River Basin in the mine concentration area as the research object,the ecological pollution risk and cumulative effect of heavy metals in the soil of the basin were studied by using the comprehensive pollution index method,potential ecological risk assessment method and geoaccumulation index method.On this basis,the cumulative exceeding years of specific heavy metals were predicted by using the early warning model.The comprehensive potential ecological risk of heavy metals in the soil near the Luanchuan mine concentration area is moderate,and the single element Cd is the main ecological risk factor,with a contribution rate of 53.6%.The overall cumulative degrees of Cu and Pb in the soil are“none-moderate”,Zn and Cd are moderate,Mo has reached an extremely strong cumulative level,Hg,As and Cr risks are not obvious,and the overall cumulative risks order is Mo>Cd>Zn>Cu>Pb>Hg.According to the current accumulation rate and taking the risk screening values for soil contamination of agricultural land as the reference standard,the locations over standard rates of Cu,Zn and Cd will exceed 78%in 90years,and the over standard rate of Pb will reach approximately 57%in 200 years.The cumulative exceeding standard periods of As,Cr and Hg are generally long,which basically indicates that these elements do not pose a significant potential threat to the ecological environment.Mining activities will accelerate the accumulation of heavy metals in soil.With the continuous development of mining activities,the potential pollution risk of heavy metals in the soil of mining areas will also increase.

Occupational risk assessment based on employees’ knowledge and awareness of hazards in mining

Analyses and assessments of hazards occurring in work processes are carried out by teams,in which there is usually one representative of the personnel,as the embodiment of the active participation of employees in the assessment of occupational risks.This is why the article presents research on all employees’knowledge and awareness about risks in their work environment.The research was carried out in the form of an employee survey in one of the open-pit mines,at workstations dealing with the loading and transporting of excavated material.The survey included a list of 40 hazards divided into four groups:(1)hazards related to machines and equipment used,(2)hazards related to exposure,(3)hazards with an impact extending beyond the workstation and(4)hazards of an ergonomic nuisance nature,where employees were required to indicate which hazards apply to their workplaces and determine their level of signifcance,probability of occurrence and the scale of possible efects.In this way,a hierarchical identifcation of threats occurring at the analyzed workplaces was made,and the obtained results were used to determine the amount of occupational risk both for specifc workstations and for the whole technological process.The measures of the magnitude of occupational risk obtained using the proposed method have showed that,according to the respondents,greatest risks at the workstation are associated with moving machines and vehicles and with mobile equipment.Equally important risks,which were often mentioned by employees,were those directly related to their health,i.e.,related to ergonomic nuisance and exposure.Threats resulting from geological and mining conditions,considered typical for mining,were important for the surveyed miners but they were not the most important owing to proper prevention,good organization of work and high safety culture The active involvement of the crew in the process of assessing occupational hazards allowed to identify the signifcance of each hazard,in the opinion of the personnel working at various places and to use this ranking for determining occupational risk levels in the mining company concerned.The research has also outlined another goal to be achieved:a comparison of the relative signifcance of hazards identifed by the employees and of the hazards listed in occupational risk assessment matrices used by mines.