华南典型离子型稀土矿区地下水污染特征及成因分析OACSTPCD

Taking the typical ion-type rare earth mining area left over from history in South China as the research object,the groundwater samples in mining area were cellected to monitor pH,"three nitrogen",heavy metals,rare earth elements and other indicators for the quality and pollution assessment and spatial distribution characteristics analysis.Methods such as Piper three-plot of hydrochemical type,soil and water concentration comparison and ionic concentration correlation analysis were adopted to further study the source,migration and transformation of the main contaminants.The results showed that the groundwater pH and NH4+-N generally exceeded the standard,and the pollution index(Pki)of NH4+-N and Pb was the highest which reached 197.70 and 96.99,respectively.The groundwater pollution in pile leaching mining area was more serious than that in situ leaching mining area.The injection of leaching agents causes soil acidification and residual ammonium nitrogen,which was an important source of ammonia nitrogen supply in groundwater in mining areas.Under acidic conditions,the likelihood of nickel,cadmium,mercury,arsenic,lead,neodymium,and lanthanum precipitation from soil increases in sequence.