A Regional Scale Investigation on Groundwater Arsenic in Different Types of Aquifers in the Pearl River Delta, China

Qinxuan Hou,Jingtao Liu,Chunyan Liu,Ying Zhang,Mengjian Hua,Jichao Sun,Jihong Jing

doi:10.1155/2018/3471295

Qinxuan Hou, Jingtao Liu + Show 5 more

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https://doi.org/10.1155/2018/3471295

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Abstract

Nearly 400 groundwater samples were collected from different types of aquifers in the Pearl River Delta (PRD), and the concentrations of groundwater arsenic (As) and other 22 hydrochemical parameters in different types of aquifers were then investigated. Results showed that groundwater As concentration was up to hundreds μg/L in granular aquifers, while those in fissured aquifers and karst aquifers were only up to dozens and several μg/L, respectively. Correspondingly, about 9.4% and 2.3% samples with high concentrations (>0.01 mg/L) of As were in granular and fissured aquifers, respectively, but no samples with high concentration of As were in karst aquifers. The source and mobilization of groundwater As in granular aquifers are likely controlled by the following mechanism: organic matter in marine strata was mineralized and provided electrons for electron acceptors, resulting in the release of NH4+ and I- and the reduction of Fe/Mn and NO3-, and was accompanied with the mobilization of As from sediments into groundwater. By contrast, both natural processes including the competitive adsorption between As anions and F-/PO43-/HCO3- and anthropogenic processes including industrialization were responsible for high concentrations of groundwater As in fissured aquifers.

Highlights

Arsenic (As) is discovered as one of the most common toxic elements in environments
The present study aims to (1) investigate the concentrations of groundwater As in different types of aquifers in the whole Pearl River Delta (PRD) on a regional scale and (2) discuss the influence factors on the distribution of groundwater As in aquifers. Multivariate statistical techniques such as principal components analysis (PCA) have been used in this study, because PCA can help to understand the hydrochemical processes and provide information about which factors are responsible for high levels of groundwater As in aquifers [7]
After the PCs were reduced from seven PCs to two PCs, we found groundwater As in granular aquifers was closely related I−, NO2−, and to NH4+ and PO43− but Mn (Figure 4)

Summary

Introduction

Arsenic (As) is discovered as one of the most common toxic elements in environments. Groundwater with high concentrations of As is a major environmental and public health problem on a global scale. The present study aims to (1) investigate the concentrations of groundwater As in different types of aquifers in the whole PRD on a regional scale and (2) discuss the influence factors on the distribution of groundwater As in aquifers. Multivariate statistical techniques such as principal components analysis (PCA) have been used in this study, because PCA can help to understand the hydrochemical processes and provide information about which factors are responsible for high levels of groundwater As in aquifers [7]. The results obtained from this study can be a useful reference on the groundwater management of this region

Study Area

Materials and Methods

Results and Discussion

Conclusions