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

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.

Indications of recent warm and dry summers' impact on private wells for drinking-water supply in Germany: a review of press articles

Climatic changes lead to seasonal droughts with declining groundwater levels, and – especially in rural regions – private wells in the upper aquifer might fall dry. However, only limited information and no systematic administrative reporting of the extent are available for Germany yet. Therefore, a systematic analysis of newspaper articles as a promising source of information was conducted for the extraordinarily hot summers of 2018, 2019 and 2020. The results of the databases' search were analysed with respect to frequency and local and regional hotspots, relations to climatic data, extent of the reported dry-fallings and emergency water supply. The analysis indicates hotspots particularly for the federal states of Saxony, where a subsidy programme for connecting to the public water supply was reissued in 2019, for Bavaria and North Rhine-Westphalia. Emergency supply was realised through various approaches. It was partly required until the winter months and did not always have drinking-water quality. As private wells are particularly vulnerable to the effects of climate change, their operators should be involved as a stakeholder group in future discussions about allocating water resources to increasingly competing uses in periods of scarcity.

Microbiological quality of well water from Koprivnica-Križevci County in 2018

In this study, microbiological quality of drinking water deriving from the private wells from Koprivnica-Križevci County was investigated. A total of 287 samples from different locations were collected during 2018 and analysed for the following microbiological parameters: total coliforms, Escherichia coli, Enterococcus spp., Clostridium perfringens, Pseudomonas aeruginosa, and the number of aerobic heterotrophic bacteria at 36 °C and 22 °C. The results showed that 24 % of the analysed water samples were of unsatisfactory microbiological quality, with high incidence of faecal contamination. Well water is still the main source of drinking water for many residents of this County, especially in its rural parts, so continuous monitoring and disinfection of drinking water deriving from private wells is of exceptional importance for the public health.

Evaluating the impact of free private well testing outreach on participants' private well stewardship in New Jersey

Over 1 million people in New Jersey (NJ) are estimated to receive drinking water from private wells. The most commonly detected contaminants in NJ private well water are naturally occurring arsenic and gross alpha (8.3 and 10.9%, respectively). Between 2015 and 2018, three free and voluntary private well testing events tested a total of 571 at-risk wells and 226 (40%) were identified as having one or more contaminants exceeding drinking water standards. Participants were invited to complete a survey to evaluate household characteristics, participant experience, and private well stewardship behavior patterns. Of 529 delivered surveys, 211 (40%) participants completed surveys. Among respondents, 63% reported plans to test their private wells in the future. Among failed wells, 45% of households reported performing mitigative action in response to the event, either through the installation of water treatment system or switching to bottled water. The survey evaluation identified previous knowledge of well contamination risks and discussing test results with a third party as important factors for promoting self-reported stewardship behavior. The evaluation provides guidance for outreach organizers to develop effective testing events and further considers the private well owners' experience of the outreach events to identify information for ‘best practices’ and improvements of future programs.

Well-Digging

Wells are of great importance in this arid zone to provide for household needs and water livestock. Well-digging by individual households in Kala has become a major activity, the number growing from 16 in 1980 to 43 in 1983. Private wells are dug mainly to exchange water with visiting livestock keepers during the dry season, in exchange for the dung from the herd, which builds up soil fertility in the village fields, and produces higher millet yields. Analysis of the profitability of well-digging explores costs and returns, for the four different household types, A, B, C, D in order to understand the wide range in returns from this investment over time. Risks to the well’s capital value, ways to control this risk, and flexibility in such an investment are described before assessing the consequences for those households unable to invest in this asset.

Development and application of an adsorption-direct extraction method for recovering nucleic acids of enteric viruses and host-specific Bacteroidales from groundwater

In this study, the adsorption-elution method was modified to concentrate viral particles in water samples and investigate the contamination of groundwater with norovirus genogroup II (NoV GII), rotavirus A (RVA), and pepper mild mottle virus (PMMoV). The mean recovery rate of a murine norovirus strain, which was inoculated into groundwater samples collected from a deep well, was the highest (39%) when the viral RNA was directly extracted from the membrane instead of eluting the adsorbed viral particles. This adsorption-direct extraction method was applied to groundwater samples (20 L) collected from deep wells used for public drinking water supply (N = 22) and private wells (N = 9). RVA (85 copies/L) and NoV GII (35 copies/L) were detected in water samples from a deep well and a private well, respectively. PMMoV was detected in 95% and 89% of water samples from deep wells and private wells, respectively, at concentrations of up to 990 copies/L. The modified method could also be used to extract bacterial DNA from the membrane (recovery rate of inoculated Escherichia coli K-12 was 22%). The Bacteroidales genetic markers specific to ruminants (BacR) and pigs (Pig2Bac) were detected in samples from a deep well and private well, respectively. The modified virus concentration method has important implications for the management of the microbiological safety in groundwater supply. IMPORTANCE We investigated the presence of enteric viruses and bacterial genetic markers to determine fecal contamination in groundwater samples from deep wells used for public drinking water supply and private wells in Japan. Groundwater is often subjected to chlorination; malfunctions in chlorine treatment result in waterborne disease outbreaks. The modified method successfully concentrated both viruses and bacteria in 20 L groundwater samples. Norovirus GII, rotavirus A, pepper mild mottle virus, and Bacteroidales genetic markers specific to ruminants and pigs were detected. Frequent flooding caused by increased incidences of extreme rainfall events promotes the infiltration of surface runoff containing livestock wastes and untreated wastewater into wells, possibly increasing groundwater contamination risk. The practical and efficient method developed in this study will enable waterworks and the environmental health department of municipal/prefectural governments to monitor water quality. Additionally, the modified method will contribute to improving the microbiological safety of groundwater.