Groundwater Quality in Agricultural Lands Near a Rapidly Urbanized Area, South China.

Lingxia Liu,Wenzhong Wang,Shihua Qi

doi:10.3390/ijerph18041783

Abstract

Understanding the groundwater quality and its factors is a key issue in the context of the use and protection of groundwater resources in agricultural areas near urbanized areas. This study assessed the groundwater quality in agricultural areas in the Pearl River Delta (PRD) by a fuzzy synthetic evaluation method and determined the main factors controlling the groundwater quality by principal component analysis (PCA). Results showed that approximately 85% of groundwater sites in agricultural lands in the PRD were good-quality (drinkable). Drinkable groundwater was 95% and 80% in fissured aquifers and porous aquifers, respectively. Poor-quality groundwater in porous aquifers was controlled by four factors according to the PCA, including the seawater intrusion; the lateral recharge and irrigation of surface water and geogenic sources for As, Fe, NH4+, and Mn; the wastewater infiltration; and the geogenic sources for iodide. By contrast, another four factors, including the infiltration of wastewater and agricultural fertilizers, the geogenic sources for heavy metals, the geogenic sources for iodide, and the irrigation of contaminated river water, were responsible for the poor-quality groundwater in fissured aquifers. Therefore, in the future, the groundwater protection in agricultural lands in the PRD should be strengthened because the majority of groundwater in these areas was good-quality and suitable for drinking and agricultural purposes. In addition, poor-quality groundwater in agricultural lands in the PRD was a small proportion and negligible because the factors for poor-quality groundwater are complicated.

Highlights

Groundwater resources are important for agricultural purposes and rural residents in agricultural areas [1,2,3], and the groundwater quality is a key issue for the management of groundwater resources in these areas
Groundwater is often used for agricultural irrigation in agricultural lands in the Pearl River Delta (PRD), south China, because it is free of charge and convenient [4]
Unlike Zhang et al [5] who focused on the groundwater quality in urbanized areas and peri-urban areas in the PRD by using this hydrochemical dataset, this study focuses on the groundwater quality in agricultural areas

Summary

Introduction

Groundwater resources are important for agricultural purposes and rural residents in agricultural areas [1,2,3], and the groundwater quality is a key issue for the management of groundwater resources in these areas. It is meaningful to understand the status of groundwater quality and the main factors controlling groundwater quality for groundwater management in agricultural areas in the PRD. The status of groundwater quality in urbanized areas and peri-urban areas in the PRD was reported, but that in agricultural areas has received little attention [5]. The groundwater quality in agricultural areas is sensitive to the contaminants originating from agricultural chemicals, such as nitrate and chloride [1,6,7]. In the PRD, the groundwater quality in agricultural areas is affected by agricultural activities but may be influenced by urbanization and industrialization, because agricultural lands are

Methods

Results

Conclusion