An assessment of groundwater quality for drinking and agricultural purposes in Ca Mau peninsula, Vietnamese Mekong Delta

Abstract

Groundwater serves as the major source for drinking water and the only fresh water source in the dry season in Ca Mau province, the Vietnamese Mekong Delta. The study is performed to assess groundwater quality in the area. Groundwater Quality Index (GWQI), magnesium hazard (MH), sodium percentage (Na%), sodium adsorption ratio (SAR), permeability index (PI) combined with geostatistical tools were conducted by using groundwater quality data from 400 samples collected from private wells. GWQI values suggest that 7%, 63%, 28%, 2%, 1% of total samples are classified into excellent, good, poor, very poor and unsuitable for drinking water. High Cl and TDS are the main cause of high GWQI values suggesting that saltwater intrusion deteriorates groundwater quality. For irrigation purposes, 4%, 17%, 36%, 43% of total samples classify into Good, Permissible, Doubtful, Unsuitable respectively by Na% indicator; 55.0%, 30.9%, 11.9%, 2.2% of total samples is Excellent, Good, Doubtful and Unsuitable according to SAR, 54% samples are unsuitable by MH index, and all samples are good by PI. This study provides useful information on groundwater quality for various purposes in Ca Mau province, that could help water management and water users to identify the necessary approach for groundwater protection and water-treatment methods before utilising the groundwater source for specific purposes in the study area.

Đánh Giá Tài Nguyên Nước Mặt Thành Phố Cà Mau, Tỉnh Cà Mau

“…Tài nguyên nước mặt của toàn tỉnh Cà Mau cũng đã được triển khai thực hiện trong một số nghiên cứu trước đây với các số liệu từ trước năm 2015 [1], [2] hoặc đánh giá diễn biến nguồn nước mùa kiệt, ranh giới mặn cho vùng bán đảo Cà Mau dưới ảnh hưởng của biến đổi khí hậu -nước biển dâng [3]. Mặt khác ở khu vực bán đảo Cà Mau nói chung và thành phố Cà Mau nói riêng đang gặp nhiều khó khăn do nguồn nước ngầm bị nhiễm mặn trong thời gian gần đây do việc khai thác quá mức phục vụ sinh hoạt và sản xuất [4]- [6]. Tài nguyên nước khu vực bán đảo Cà Mau cũng đã có những dấu hiệu bị tổn thương [7].…”

Groundwater resources in Bac Lieu province, Mekong Delta: current groundwater extraction and related issues

“…Salinization can cause by many processes such as infiltration of seawater from surface, up-conning by over extraction [5]. Consequently, using of contaminated groundwater can adversely impacts on human health and reduce agriculture production [6]. Groundwater is a hidden recourse; therefore, sustainable management of groundwater in the coastal aquifer is not an easy task [2].…”

“…The city has about 158 000 people [10] and mostly dependent on groundwater for their drinking purpose [11]. Salinization and contamination of groundwater are observed in some surrounding area of Bac Lieu Province such as Ca Mau [12], Soc Trang province [13]. Groundwater issues in the Bac Lieu Province is rarely reported, therefore, this paper aims to understand groundwater system, current groundwater extraction and groundwater problems.…”

Use of hydrogeochemical tools to evaluate seawater intrusion: a case study of Upper Pliocene Aquifer in the Ca Mau Peninsula, Vietnam

“…Every year, CMP faces the problem of increasingly serious drought and salinity, leading to increasing demand for groundwater exploitation [3]. Ha Quang Khai et al, 2022 pointed out that about 31% of groundwater samples in the Ca Mau Peninsula were classified as poor and unsuitable for drinking purposes [4]. Bauer et al, 2022 [5] indicated obvious evidence of recent salinization, which may be caused by the vertical penetration of saline Holocene groundwater through natural and anthropogenic pathways into deep aquifers.…”

“…Bauer et al, 2022 [5] indicated obvious evidence of recent salinization, which may be caused by the vertical penetration of saline Holocene groundwater through natural and anthropogenic pathways into deep aquifers. Ha Quang Khai et al, 2021 [4] pointed out that saline groundwater is widely observed in aquifer systems by spatial analysis of TDS (Total Dissolved Solid) data and wells in the study area have to be carefully installed by vertical seepage of saline groundwater from shallow aquifers. Nguyen Dang Tinh et al, 2020 estimated that the secure fresh groundwater exploitable reserve for the n2 2 aquifer in the Ca Mau Peninsula area is 130,684 m 3 /day [6].…”