Hydrogeochemical Characterization and Quality Assessment of Groundwater in a Long-Term Reclaimed Water Irrigation Area, North China Plain

Xiaomin Gu,Geping Meng,Zhongyong Hao,Yong Xiao,Huijun Yan,Qiuming Pei,Shiyang Yin,Qichen Hao,Honglu Liu

doi:10.3390/w10091209

Abstract

Water scarcity has led to wide use of reclaimed water for irrigation worldwide, which may threaten groundwater quality. To understand the status of groundwater in the reclaimed water irrigation area in Beijing, 87 samples from both shallow and deep aquifers were collected to determine the factors affecting groundwater chemistry and to assess groundwater quality for drinking and irrigation purposes. The results show that groundwater in both shallow and deep aquifers in the study area is weakly alkaline freshwater with hydrogeochemical faces dominated by HCO3-Na·Mg·Ca, HCO3-Mg·Ca·Na, HCO3-Ca·Na, and HCO3-Na. The chemical composition of groundwater in both shallow and deep aquifers is dominantly controlled by the dissolution of halite, gypsum, anhydrite, and silicates weathering, as well as ion exchange. Geogenic processes (rock weathering and ion exchange) are the only mechanisms controlling groundwater chemistry in deep aquifers. Besides geogenic processes, evaporation and anthropogenic activities also affect the chemistry of shallow groundwater. Quality assessment reveals that both shallow and deep groundwater are generally suitable for drinking and irrigation purposes. The quality of deep groundwater is more excellent for drinking than shallow groundwater. However, long-term use of deep groundwater for irrigation exhibits higher potential risks to deteriorate soil property due to the relative higher permeability indexes (PI). Therefore, it is recommended that deep groundwater is preferentially used for drinking and domestic purpose, and shallow groundwater for agricultural irrigation.

Highlights

Water scarcity has been one of the most serious problems that restrict economic development in many regions around the world, especially in arid and semiarid regions [1,2]
The shortage of water sources led to long-term use of wastewater and reclaimed water for irrigation in the semi-arid regions, and it may threaten the quality of groundwater as well
Factors influencing groundwater chemistry and its quality in Beijing were discussed in detail

Summary

Introduction

Water scarcity has been one of the most serious problems that restrict economic development in many regions around the world, especially in arid and semiarid regions [1,2]. Water 2018, 10, 1209 for agricultural, domestic, and industrial purposes [3,4] These purposes are dominantly controlled by groundwater chemistry [5]. In order to alleviate the water shortage, wastewater and reclaimed water have been utilized for agricultural irrigation in Beijing Plain since the 1950s [9]. Water reuse for irrigation may lead to some negative environmental consequences, such as soil structure deterioration, enrichment of heavy metals and other pollutants in soils and agricultural corps, groundwater pollution as well [9,10]. Bao et al found that long-term wastewater irrigation had resulted in nutrient elements and heavy metals accumulation in soil at some extent, but it did not constitute pollution in shallow groundwater [16,19].

Objectives

Methods

Results

Conclusion