Assessment of Groundwater Quality in the Holocene Aquifer in Duy Tien District, Ha Nam Province using Groundwater Quality Index (GWQI)

Abstract

This study aims to assess the pollution level of groundwater in the Holocene aquifer in the Duy Tien district, Ha Nam province, using the groundwater quality index (GWQI). Groundwater samples were collected from 20 wells and dug wells in households in rainy and dry seasons. The results showed that many parameters such as ammonium, nitrite, total hardness, chloride, Fe, Mn, Pb, As exceeded the permitted limits according to QCVN 09-MT: 2015/BTNMT. In particular, the ammonium concentrations at all monitoring wells were higher 2,73 ÷ 28,3 times than permitted values. The GWQI ranged between 84 ÷ 369 in the rainy season and 67 ÷ 290 in the dry season, while the proportion of wells with "very poor water" quality in the rainy and dry season was 50% and 65%, respectively. The GWQI values can be a scientific basis for effective use and protecting groundwater resources.

Evaluating Groundwater Quality Using Multivariate Statistical Analysis and Groundwater Quality Index

“…Groundwater in Soc Trang province had a significant concentration of Fe (0.04-19.8 mg/L, averaged at 2.17 mg/L) [37]. Other studies also found high Fe concentrations in groundwater [28,33,51]. The Fe concentration in groundwater in the former study was higher than that in the current study.…”

“…The causes of groundwater pollution at the GW24 site may be due to seawater intrusion and improper wastewater and waste management. Compared with other studies, the overall groundwater quality in Ca Mau was better than that in Ha Nam province (GWQI 67-369) [33], but it was worse than the groundwater quality in Ba Ria -Vung Tau [19] and the groundwater quality in Dong Thap, An Giang, Hau Giang, and Kien Giang [15]. The difference in results of GWQI in various areas in the current and former studies could be from the input data.…”

“…Former studies also measured pH values in groundwater. For example, pH in groundwater wells in the Ho Chi Minh City area was in the range of 3.4-7.4 [28], in the areas of Ba Ria -Vung Tau, it was 4.30-7.80 [19], and in the areas of Ha Nam Province, it was 6.19-7.33 [33]. A previous study also found that groundwater pH in the Mekong Delta of Vietnam was in the range of 6.54-7.76 [15].…”

“…Sources of NH4 + -N contaminating groundwater could be inappropriate discharges of waste and wastewater from domestic and industrial activities, landfill leachate, and the application of fertilizers in agriculture [15,20,23,28,37,46]. NH4 + -N in groundwater was found up to 28.2 mg/L in Duy Tien district in Ha Nam province [33], at 16,086 mg/L at Xuan Mai town in Hanoi [47], and at 57.3 mg/L at Valley Kathmandu in Nepal [48]. Other studies found NH4 + -N concentrations in groundwater in the Mekong Delta, Vietnam, at 0.24-10.8 mg/L [18], 0.07-2.55 mg/L in An Giang groundwater [24], and 0-7 mg/L in Tra Vinh groundwater [23].…”