Groundwater Quality Surroundings Mining Activities Areas in Arlit Region(Tim MersoïBasin,North Niger)

The study area is a semi-arid area located in the Arlit region.This area contains significant uranium deposits that have been mined by two mining companies since 1968.The objective of this study is to determine the impact of these activities on existing aquifers,in particular Izegouande aquifer.A methodological approach based on hydrochemical methods focusing on the analysis of nitrates and sulfates showed that waters of Izegouande aquifer have high nitrate concentrations ranging from 16 mg/L to 60 mg/L,higher than WHO(World Health Organization)standards drinking water.In addition,these waters show elevated sulfate levels ranging from 16 mg/L to 57 mg/L,therefore acceptable.These high concentrations of nitrates and sulfates are located mainly near wastewater treatment of Arlit city and near industrial zone,which are potential areas for transfer of these elements such as nitrates and sulfates.It is therefore urgent to carry out periodic and regular checks on groundwater in these areas.

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.