Assessment of groundwater quality of middle – Upper pleistocene aquifer in Ca Mau peninsula

Abstract

Groundwater quality is a matter of concern in Ca Mau Peninsula. There have been many organizations, domestic and foreign scientific researchersworking on the issue, and they have produced various results regardinggroundwater pollution (arsenic, heavy metal, minerals, or saltwater intrusion…). In this paper, the authors assess groundwater quality by using the water quality index (WQI) to transform complex data into simple indicators that are easy to understand, and let people in the studied areas be aware of the pollution issue of the water resources they are using. Groundwater samples are collected from national monitoring wells and from exploitation works in the area. Indicators such as pH, TDS (total dissolved solids), total hardness (TH), total alkalinity (Na ++ K +), sulfate (SO42-), chloride (Cl), and nitrate ( NO3) are used to calculate WQI values.The WQI values of the middle Pleistocene aquifers of Ca Mau Peninsula range from 36.09 to 1,344. Based on these values, authors have classified groundwater samples into 5 groups of different qualities, from the very high quality to the unusable one. The very high quality accounts for 14% of the samples; good quality accounts for 49%, average quality accounts for 24%, poor quality accounts for 7%, and unusable accounts for 6% of the total samples.There is about 10% of the samples exceeding permissible limits of TDS, whereas the sulfate and chloride range from 20% to 21%. Samples of poor and unusable qualityare mainlyfrom Soc Trang province. Most of themhavethe TDS levels greater than 1, and some have an abnormally high level ofsulfatewhen compared with other samples in the area. The study hasyielded a more comprehensive assessment of groundwater quality, allowing regulators to plan water resources more reasonably and be able togive in time advices tothe people.

Groundwater Quality Assessment Using Water Quality Index, Principal Component and Cluster Analyses: A Case Study

“…The groundwater quality index (GWQI) was used to evaluate overall groundwater quality. GWQI was calculated using the formula (1) (Dao et al, 2016;Li et al, 2021):…”

“…Especially, in the Mekong delta, surface water has been strongly polluted by agricultural and aquaculture activities, salinity intrusion, domestic and industrial contaminants. Therefore, this water resource is unsuitable for human use and places more importance on alternative freshwater resources such as groundwater (Dao et al, 2016). However, the availability and quality of groundwater are currently affected by both natural processes and anthropogenic activities.…”

“…For example, CA classified all monitoring sites into two clusters based on the pollution index of groundwater and ecological risk index, which benefits recognizing the areas that need to treat contaminated groundwater before drinking in Ojoto (Egbueri, 2020). In Mekong Delta, the groundwater quality index (GWQI) has been applied in previous studies to evaluate groundwater quality (Dao et al, 2016;Huynh et al, 2019). This tool can combine many different water parameters into only one index, which allows recognizing the composite impact of these parameters on groundwater in a particular area.…”

“…Huynh et al (2019) reported that the northeast and southeast regions of An Giang were classified as "bad water" for the period of ten years (2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018) based on the results of GWQI. Dao et al (2016) calculated the GWQI in Ca Mau Peninsula in the range of 36.09 to 1,344.00, with approximately 50% of total samples in the good quality group. To the best of our knowledge, there are no comprehensive studies that assess groundwater quality using the WQI, PCA, and CA in Can Tho City.…”

Groundwater quality evaluation using Water Quality Index and GIS technique for the Holocene and Pleistocene aquifers in the coastal zone of Ninh Thuan province

“…Ngoài ra, một số nghiên cứu khác đã sử dụng chỉ số WQI để đánh giá chất lượng NDĐ dựa trên các thông số hóa lý và hóa học ở khu vực Cà Mau, Tp. Hồ Chí Minh, Bà Rịa-Vũng Tàu,… [20,21] để dễ dàng nhận định về các vấn đề ô nhiễm nguồn nước đang sử dụng trong ăn uống và sinh hoạt hàng ngày. Tuy nhiên, khu vực ven biển tỉnh Ninh Thuận, các nghiên cứu trước đây chủ yếu đánh giá chất lượng nước mặn -nhạt ở các tầng chứa nước [22] thông qua thông số TDS.…”