Anthropogenic activities in the Pearl River Delta （PRD） have caused a deterioration of groundwater quality over the past twenty years as a result of rapid urbanization and industrial development. In this study, the ...Anthropogenic activities in the Pearl River Delta （PRD） have caused a deterioration of groundwater quality over the past twenty years as a result of rapid urbanization and industrial development. In this study, the hydrochemical characteristics, quality, and sources of heavy metals in the groundwater of the PRD were investigated. Twenty-five groundwater samples were collected and analyzed for pH, electrical conductivity （EC）, total dissolved solids （TDS）, δ18O,δ~2H, major ions, and heavy metals. The groundwater was slightly acidic and presented TDS values that ranged from 35.5 to 8,779.3 mg.L-1. The concentrations of the major ions followed the order Cl- 〉 HCO3-〉 Na＋ 〉 SO24- 〉 NO3 〉 NH4＋ 〉 Ca2＋ 〉 K＋ 〉 Mg2＋ 〉 Fe2＋/3＋ 〉 Al3＋. Ca-Mg- HCO3 and Na-K-HCO3 were the predominant types of facies, and the chemical composition of the groundwater was primarily controlled by chemical weathering of the basement rocks, by mixing of freshwater and seawater and by anthropogenic activities. The heavy metal pollution index （HPI） indicated that 64% of the samples were in the low category, 16% were in the medium category and 20% were in the high category, providing further evidence that this groundwater is unsuitable for drinking. Lead, arsenic, and manganese were mainly sourced from landfill leachate; cadmium from landfill leachate and agricultural wastes; mercury from the discharge of leaehate associated with mining activities and agricultural wastes; and chromium primarily from industrial wastes. According to the irrigation water quality indicators, the groundwater in the PRD can be used for irrigation in most farmland without strong negative impacts. However, approximately9 million people in the Guangdong Province are at risk due to the consumption of untreated water. Therefore, we suggest that treating the groundwater to achieve safer levels is necessary.展开更多
基金This study is supported in part by grants from the National Natural Science Foundation of China （ Grant No. 41103007）, the Fundamental Research Funds for the Beijng Jiaotong University （No. C13JB00070） and Beijing Natural Science Foundation （No. 8142031）. The authors express that great thanks to the anonymous reviews for their time and efforts.
文摘Anthropogenic activities in the Pearl River Delta （PRD） have caused a deterioration of groundwater quality over the past twenty years as a result of rapid urbanization and industrial development. In this study, the hydrochemical characteristics, quality, and sources of heavy metals in the groundwater of the PRD were investigated. Twenty-five groundwater samples were collected and analyzed for pH, electrical conductivity （EC）, total dissolved solids （TDS）, δ18O,δ~2H, major ions, and heavy metals. The groundwater was slightly acidic and presented TDS values that ranged from 35.5 to 8,779.3 mg.L-1. The concentrations of the major ions followed the order Cl- 〉 HCO3-〉 Na＋ 〉 SO24- 〉 NO3 〉 NH4＋ 〉 Ca2＋ 〉 K＋ 〉 Mg2＋ 〉 Fe2＋/3＋ 〉 Al3＋. Ca-Mg- HCO3 and Na-K-HCO3 were the predominant types of facies, and the chemical composition of the groundwater was primarily controlled by chemical weathering of the basement rocks, by mixing of freshwater and seawater and by anthropogenic activities. The heavy metal pollution index （HPI） indicated that 64% of the samples were in the low category, 16% were in the medium category and 20% were in the high category, providing further evidence that this groundwater is unsuitable for drinking. Lead, arsenic, and manganese were mainly sourced from landfill leachate; cadmium from landfill leachate and agricultural wastes; mercury from the discharge of leaehate associated with mining activities and agricultural wastes; and chromium primarily from industrial wastes. According to the irrigation water quality indicators, the groundwater in the PRD can be used for irrigation in most farmland without strong negative impacts. However, approximately9 million people in the Guangdong Province are at risk due to the consumption of untreated water. Therefore, we suggest that treating the groundwater to achieve safer levels is necessary.
