Safe Limits For Drinking Water Research Articles

Addressing Nitrate Contamination in Groundwater: The Importance of Spatial and Temporal Understandings and Interpolation Methods

Iranian water security is threatened by groundwater (GW) degradation. The excessive use of GW for agriculture in Iran is degrading these resources. Livestock waste disposal and sewage irrigation are also major contributors. Nitrate (NO3) contamination in GW is a growing global concern, posing serious health and environmental risks. Soil can easily leach NO3 into GW, causing long-term contamination. Understanding the temporal and spatial patterns of NO3 pollution is vital in protecting human health and establishing safe drinking water limits. Choosing an appropriate interpolation method is crucial for creating a reliable spatial variability map, which is essential for environmental research and decision-making. This study used 85 GW samples collected over four periods to create interpolated maps and examine the spatial variability of NO3 levels. Spatial interpolation methods were performed using the geostatistical tool within ArcGIS Software. The results showed that Empirical Bayesian Kriging (EBK) was the most effective of the five evaluated interpolation methods, although the performance of each method varied depending on the period sampled. Therefore, the choice of interpolation method should be tailored to the study’s specific needs and the characteristics of the data being interpolated. The EBK method produced interpolation maps that illustrated the spatial distribution of NO3 concentrations, both within and exceeding the recommended guidelines. Interpolation methods can assist in creating spatial maps of NO3 concentrations, identifying pollution sources, and developing targeted management strategies. These maps demonstrate the potential impact of human activities on the observed patterns. A thorough understanding of Iran’s current GW quality is very important and valuable for management and policymakers.

Surface water quality, public health, and ecological risks in Bangladesh-a systematic review and meta-analysis over the last two decades.

Water quality has recently emerged as one of the utmost severe ecological problems being faced by the developing countries all over the world, and Bangladesh is no exception. Both surface and groundwater sources contain different contaminants, which lead to numerous deaths due to water-borne diseases, particularly among children. This study presents one of the most comprehensive reviews on the current status of water quality in Bangladesh with a special emphasis on both conventional pollutants and emerging contaminants. Data show that urban rivers in Bangladesh are in a critical condition, especially Korotoa, Teesta, Rupsha, Pashur, and Padma. The Buriganga River and few locations in the Turag, Balu, Sitalakhya, and Karnaphuli rivers have dissolvable oxygen (DO) levels of almost zero. Many waterways contain traces of NO3, NO2, and PO4-3 pollutants. The majority of the rivers in Bangladesh also have Zn, Cu, Fe, Pb, Cd, Ni, Mn, As, and Cr concentrations that exceed the WHO permissible limits for safe drinking water, while their metal concentrations exceed the safety threshold for irrigation. Mercury poses the greatest hazard with 90.91% of the samples falling into the highest risk category. Mercury is followed by zinc 57.53% and copper 29.16% in terms of the dangers they pose to public health and the ecosystem. Results show that a considerable percentage of the population is at risk, being exposed to contaminated water. Despite hundreds of cryptosporidiosis cases reported, fecal contamination, i.e., Cryptosporidium, is totally ignored and need serious considerations to be regularly monitored in source water.

Investigating the current trend of selected heavy metal pollution with possible ecological and human health effects along the uMgeni River of KwaZulu-Natal, South Africa

ABSTRACT This study aims to evaluate the concentrations, water quality analysis and health risk assessment of metals contained in water, soil and sediment samples along the uMgeni River, Durban, South Africa. Eleven heavy metals were studied and analysed using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). The concentrations of the heavy metal in water samples were in the order of As > Mn > Cd > Cr > Mo > Zn > Cu > Co > Ag > Ni with Pb not been detected in the water samples. All the heavy metals were found to be higher than the tolerable limits for safe drinking water as provided by the WHO and USEPA except for the Zn and Pb which were lower. The water quality index, heavy metal environmental index, and heavy metal toxicity index revealed that the quality of the water is poor and unfit for both domestic and irrigation uses. Similarly, the health risk assessment revealed that both carcinogenic-non-carcinogenic risk values for the heavy metals were higher than the threshold values provided by the USEPA and were more prevalent for children than adults.

An integrated approach for the characterization of groundwater quality using multivariate statistical techniques and spatial analysis

ABSTRACT. Ground water accessed via wells in areas of Tiruvallur district of the southern Indian state of Tamil Nadu has been a subject to increase sea-water intrusion. The present study highlights the potable water crisis in the northern district evaluated using GIS-assisted determination of water quality parameters across fifty sampling sites. The most informative parameters evaluated within this study were TDS, EC, TH, Na+, Mg2+, Ca2+, Cl- and SO42- while parameters such as pH, CO32-, etc. had limited correlated significance to water quality. The total dissolved solids (TDS) and electrical conductivity (EC) determined in the study area indicated significantly elevated levels across the sampling sites. Weighted arithmetical indexing (WAI) of the water quality parameters indicated 30 out of 50 water sources meet the tolerance limits for both drinking and irrigation. Based on BIS standards, only 13 sites met acceptable limits for safe drinking water. Principal component analysis and piper plot analysis revealed a significant involvement of Mg2+, Na+, Cl- and SO42- in the impairment of water quality, particularly in the coastal zones. Spatial hydro-chemical profiles developed in this study reveal ‘hot-spots’ of sea-water tainted water sources, and the hydro-chemical dominance of alkali earth components. Altogether, the study findings indicate a widening water crisis on top of over-exploited water resources and discuss possible factors and remedial steps in addressing the situation.
 
 KEY WORDS: Ground water, Principal component analysis, Piper Plot, Water quality index, Irrigation suitability
 
 Bull. Chem. Soc. Ethiop. 2022, 36(2), 241-260. 
 DOI: https://dx.doi.org/10.4314/bcse.v36i2.1

English

This research investigates the microbial and physicochemical characteristics of five local hand dug wells used for drinking and agricultural activities in Blama, Small-Bo Chiefdom, in the Kenema District, Eastern Province of Sierra Leone. These five local hand-dug wells were randomly selected based on the availability of water in them throughout the year. The physical characteristics examined are: pH, turbidity, conductivity, temperature, total dissolve solid (TDS); and the chemical characteristics, such as: Residual chlorine (R. Chorine), magnesium, potassium, nitrite, iron, fluoride, ammonia, copper; and the microbial characteristics include: Total coliforms, fecal coliform and non-fecal coliform. Samples were collected in 500 ml sterilized plastic containers and transported to the laboratory, within 30 min. The results analysed indicate that the physical and chemical characteristic are within the WHO guideline limits for safe drinking water. However, a large amount of non-Faecal coliform was recorded in all the water samples analysed which exceed the World Health Organization standard for non-faecal coliform ((<10), and with no presence of residual chlorine. It can therefore be concluded that the water sample analyzed was potable and fit for drinking and agricultural activities. Key words: Hand-dug, well, local, safe and sample.

Comprehensive Assessment of the Effect of Various Anthropogenic Activities on the Groundwater Quality

Water pollution had become a major problem due to its’ negative impact on the human health. Effects of humaninduced actions on groundwater quality were examined in this study. The physicochemical, heavy metals and microbial parameters of groundwater, sampled during the two major climatic periods in Nigeria, were measured according to APHA approved procedures. Results obtained from laboratory tests revealed that anthropogenic activities had substantial effect on the groundwater quality. The groundwater TDS, nitrate, BOD, chloride and phosphate concentrations varied from 23.93 to 42.32 mg/L, 0.54 to 2.16 mg/L, 2.23 to 4.72 mg/L, 10.78 to 19.15 mg/L, and 0.22 to 0.36 mg/L respectively. Likewise, Cd concentration fluctuated between 0 and 0.001 mg/L, Cu varied between 0 and 0.149 mg/L, Fe varied between 0 and 0.293 mg/L, Pb varied between 0 to 0.105 mg/mL, Zn varied between from 0 and 0.768 mg/L, while Ni fluctuated between 0 and 0.001 mg/L. The findings revealed that areas with poor sanitary situations had poor groundwater quality, compared to the areas with improved sanitary situations. Regarding the microbial population, the highest Total Bacteria and Fungi Counts recorded in the groundwater were 1.11×102 cfu/mL and 1.23×102 cfu/mL respectively. Similarly, the highest recorded Enterobacterial spp., Staphylococus arurius, E. coli, Proteus spp. and Shegeela spp. populations were 26.22×102 cfu/mL, 1.23×102 cfu/mL, 0.41 MPN/100 mL, 0.12 cfu/ml and 0.30×102 cfu/mL respectively. Although, the groundwater physicochemical parameters and heavy metals concentrations were within safe drinking water limits; the groundwater was largely contaminated with pathogenic microorganisms, mostly during the rainy season.

Appraisal of vulnerable zones of non-cancer-causing health risks associated with exposure of nitrate and fluoride in groundwater from a rural part of India

The present investigation carried out from a rural part of Nalgonda district, Telangana, India was to know the general groundwater quality and also to measure the vulnerable zones of non-cancer-causing health risks with respect to infants, children, and adults due to the consumption of nitrate and fluoride contaminated groundwater. Groundwater samples were collected from the study area and analyzed for the major physicochemical parameters. Nitrate and fluoride contents ranged from 2 to 700 mg/L and 0.3 to 4.7 mg/L, in which 59.09% and 31.82% of the groundwater samples exceed the safe drinking water limits of 45 mg/L and 1.5 mg/L, which spread over an area of 77.59% and 25.41%, respectively. Domestic wastes, septic tank spillages, animal wastes, and nitrate composts are the prime sources of nitrate, while the fluoride-bearing minerals and phosphate fertilizers are the main sources of fluoride in the aquifer regime. Individual non-cancer-causing health index obviously suggested the nitrate as the higher health risk than fluoride. The total non-cancer-causing health index was observed to be more than the acceptable limit of 1.0 in 95.5% of the total groundwater samples concerning infants, children, and adults. The vulnerable intensity of this index appeared to be higher in infants than in children and adults due to the differences in their body weights. The spatial coverage area of very health risk is more in infants (37.45%) than that of children (36.78%) and adults (30.34%). Thus, the present study suggested suitable measures for the improvement of groundwater quality and consequently the health conditions of the locals.

AQUIFER CHARACTERIZATION AND PHYSIOCHEMICAL ANALYSIS OF DISTRICT DERA GHAZI KHAN PUNJAB, PAKISTAN

The study area is located in the arid section of Punjab province, Pakistan. The accessibility of freshwater is the main problem in this area. The area is mainly flat and alluvial deposits are present down to 800 m. The groundwater is not fit for drinking because of its salinity. Hence, it is essential to mark the transition between fresh water and saltwater. Resistivity models were used to locate freshwater areas. The saltwater areas are between 10 and 30 m deep. Salt flats and clayrich deposits are visible on resistivity maps and were identified by low resistance values. After linking resistivity data and maps, it is determined that the south portion of the area has a freshwater aquifer, especially at a depth of 200 m. At this depth, the quality of water is very good, regardless of its mild salinity in some areas. The margin between salty and freshwater is set to no degree. This is dependent upon the recharge and usage of an aquifer. Groundwater pollution poses a severe threat to the city’s residents. Results from the physio-chemical analysis of the water samples confirm the presence of arsenic in excessive amounts in water samples and are outside the limits set by the WHO and NDWQS. Just two out of 10 samples are within the limits for safe drinking water. The results of this research are valued for groundwater management and the installation of tubular wells in freshwater areas for households and irrigation purposes.

Effect of Distance of Sanitary Pits on the Physicochemical Properties of Hand Dug Well Water Samples Consumed by People Living in Akwuke Community, Enugu South Local Government Area of Enugu State

Studies were carried out to evaluate the effect of distance of sanitary pits on the physicochemical properties of hand-dug well water samples consumed by people living in Akwuke community, Enugu South Local Government Area of Enugu State, using standard analytical procedures and instrumentation. The mean range of pH, turbidity, electrical conductivity, total dissolved solids, nitrate and sulphate in the well water samples at the determined sampling distances of 3, 6 and 10 m from the sanitary pits were 5.9 - 7.24, 1.92 - 6.63 NTU, 122.03 - 303.91 μs/cm, 100.00 - 261.90 mg/L, 1.21 - 4.68 mg/L and 28.89 - 49/61 mg/L respectively. The investigated mean physicochemical parameters of the well water samples were generally observed to increase with decrease in the distance of the well water samples from the sanitary pits. The levels of the determined physicochemical parameter of the well water samples at sampling distances of 3, 6, and 10 m respectively from the sanitary pits were statistically significant. The mean pH values of the well water samples at sampling distances of 3 and 6 m respectively from the sanitary pits were below the WHO recommended threshold limits for safe drinking water. Additionally, the mean values of turbidity and total dissolved solids of the well water samples at a sampling distance of 3 m from the sanitary pits were above the WHO permissible limits. The pH, turbidity and total dissolved solids are some of the most important parameters used in assessing the quality of any water source, therefore, the poor physicochemical properties of well water samples at a sampling distance of 3 m from the sanitary pits could put at severe health risk consumption of this water over a prolonged time. Siting well water at a reasonable far distance (above 10 m) for sanitary pits especially in communities with severe water scarcity would definitely help guarantee access to safe drinking water by rural as well as urban dwellers in Nigeria.

The direct and indirect effects of copper on vector-borne disease dynamics

Metal pollution is a growing concern that affects the health of humans and animals globally. Copper is an essential insect micronutrient required for respiration, pigmentation and oxidative stress protection but can also act as a potentially toxic trace element. While several studies have focused on the negative fitness effects of copper on the aquatic larvae of mosquitoes, the effects of larval copper exposure on adult mosquito fitness (i.e., survival and fecundity) and their ability to transmit parasites (i.e., vector competence) remains unclear. Here, using a well-studied model vector-parasite system, the mosquito Aedes aegypti and parasite Dirofilaria immitis, we show that sublethal copper exposure in larval mosquitoes alters adult female fecundity and vector competence. Specifically, mosquitoes exposed to copper had a hormetic fecundity response and mosquitoes exposed to 600μg/L of copper had significantly fewer infective parasite larvae than control mosquitoes not exposed to copper. Thus, exposure of mosquito larvae to copper levels far below EPA-mandated safe drinking water limits (1300μg/L) can impact vector-borne disease dynamics not only by reducing mosquito abundance (through increased larval mortality), but also by reducing parasite transmission risk. Our results also demonstrated that larval copper is retained through metamorphosis to adulthood in mosquitoes, indicating that these insects could transfer copper from aquatic to terrestrial foodwebs, especially in urban areas where they are abundant. To our knowledge this is the first study to directly link metal exposure with vector competence (i.e., ability to transmit parasites) in any vector-parasite system. Additionally, it also demonstrates unequivocally that mosquitoes can transfer contaminants from aquatic to terrestrial ecosystems. These results have broad implications for public health because they directly linking contaminants and vector-borne disease dynamics, as well as linking mosquitoes and contaminant dynamics.

Evaluation of low-cost alternatives for water purification in the stilt house villages of Santa Marta's Ciénaga Grande

Water purification is indispensable to guarantee safe human consumption and to prevent diseases caused by the ingestion of contaminated water. This requires a series of water treatment processes which require investment. However, the economic limitations of rural communities hinder their ability to implement such water-treatment systems, as is the case in Ciénaga Grande of Santa Marta (“Large Swamp”, in English) in Colombia. Low-cost systems can be used instead as simple and safe alternatives. Therefore, the objective of this work was to evaluate non-conventional, low-cost water processes to purify the water from the collection point of two stilt house villages in Ciénaga Grande of Santa Marta. These include: 1) Using two natural coagulants, Moringa Oleifera and Cassia Fistula; 2) filtration through a biosand filter and a carbon activated filter; and 3) disinfection through UV-C Radiation and through solar disinfection. The results showed a turbidity values reduction between 52% and 96% using the two natural coagulants; both turbidity and total coliforms achieved reductions of 98.4% and 76.9%, respectively in the filtration process; and removal of total coliforms up to 98.8% in the disinfection process. Despite the high rates of reduction in the different parameters, the water does not comply with the recommended limits for safe drinking water.

Trends and probabilistic stability index for evaluating groundwater quality: The case of quaternary alluvial and quartzite aquifer system of India

This study proposed a novel groundwater-quality stability index (GQSI), which considers probabilistic estimate of reliability and resilience based on multi-year dataset. The developed index is validated and optimized adopting optimum index factor approach. The vulnerabilities of different groundwater quality parameters are also computed to provide an insight about the deviations of their concentrations from the safe drinking water limits. The application of the developed stability index is demonstrated through a case study in quaternary alluvial and quartzite aquifer system of India. In addition, trends in the groundwater quality parameters are identified by using variance-corrected Mann-Kendall test, and trends are quantified by using Sen's slope estimation test. Box-whisker plots revealed that EC and TDS mostly exceed their maximum permissible limits prescribed for drinking water in the southern and southwest hard-rock formations. Whereas, most parameters do not cross their maximum desirable limits in the central and northern alluvial formations. Increasing trends of potassium and bicarbonate, and decreasing trends of carbonate, calcium, sulfate, and fluoride are found prominent. The GQSI values indicated high stability of groundwater quality under older alluvium geology and low stability under the gneiss and mica-schist. Results of the GQSI are found in agreement with that of groundwater-quality index (GQI) at 84% sites, which proved adequacy of the developed GQSI. Also, three classes (‘low’/‘poor’, ‘moderate’, and ‘high’/‘good’) of both the GQSI and GQI showed a good coherence at 83, 78, and 87% sites. However, GQSI is more advantageous than GQI due to former's statistical framework, consistency and comparability over different areas. Three optimum index factors, i.e., TDS, pH and nitrate, are found to have the maximum impact on overall groundwater quality with their largest variations. Results of the optimum groundwater-quality stability index (OGQSI) and GQSI closely matched with each other, and a significant linear relationship (R2 = 0.70) existed between them. Therefore, OGQSI is a cost-effective approach for adequate monitoring and satisfactory evaluation of the groundwater quality in low-income nations.

Environmental status of groundwater affected by chromite ore processing residue (COPR) dumpsites during pre-monsoon and monsoon seasons.

Chromite ore processing residue (COPR) is generated by the roasting of chromite ores for the extraction of chromium. Leaching of carcinogenic hexavalent chromium (Cr(VI)) from COPR dumpsites and contamination of groundwater is a key environmental risk. The objective of the study was to evaluate Cr(VI) contamination in groundwater in the vicinity of three COPR disposal sites in Uttar Pradesh, India, in the pre-monsoon and monsoon seasons. Groundwater samples (n=57 pre-monsoon, n=70 monsoon) were taken in 2014 and analyzed for Cr(VI) and relevant hydrochemical parameters. The site-specific ranges of Cr(VI) concentrations in groundwater were <0.005 to 34.8mgL-1 (Rania), <0.005 to 115mgL-1 (Chhiwali), and <0.005 to 2.0mgL-1 (Godhrauli). Maximum levels of Cr(VI) were found close to the COPR dumpsites and significantly exceeded safe drinking water limits (0.05mgL-1). No significant dependence of Cr(VI) concentration on monsoons was observed.

Assessment of some potential harmful trace elements (PHTEs) in the borehole water of Greater Giyani, Limpopo Province, South Africa: possible implications for human health.

The present investigation was conducted in order to evaluate the occurrence and distribution patterns of some potentially harmful trace elements in the borehole water of the Greater Giyani area, Limpopo, South Africa, and their possible implications on human health. Twenty-nine borehole water samples were collected in the dry season (July/August 2012) and another 27 samples from the same localities in the wet season (March 2013) from the study area. The samples were analysed for trace elements arsenic (As), cadmium (Cd), chromium (Cr), selenium (Se), and lead (Pb) using the inductively coupled plasma mass spectrometry technique. The average concentrations of As, Cd, Cr, Se, and Pb were 11.3, 0.3, 33.1, 7.1, and 6.0µg/L in the dry season and 11.0, 0.3, 28.3, 4.2, and 6.6µg/L inthe wet season, respectively. There was evidence of seasonal fluctuations in concentrations of all analysed elements except for As, though Cd and Pb displayed low concentrations (<0.2 and <6.0µg/L, respectively) in almost all sampled boreholes. Se and Cr concentrations slightly exceed the South African National Standard permissible limits for safe drinking water in few boreholes. A total of four boreholes exceeded the water quality guideline for As with two of these boreholes containing five times more As than the prescribed limit. The spatial distribution patterns of elevated As closely correlate with the underlying geology. The findings of this investigation have important implications for human health of the communities drinking from the affected boreholes.

Modelling the Spatial Distribution of Arsenic in Water and Its Correlation with Public Health, Central Indus Basin, Pakistan

Like India, Bangladesh and China, Pakistan also has some regions where concentration of Arsenic in water has crossed the WHO safe drinking water limits, 10 ppb. Presence of Arsenic in drinking water is causing serious human health issues for the local residents of Sindh and southern Punjab, which needs serious attention. The present study is focused on the spatial distribution of Arsenic in groundwater and its relationship with the major reported human diseases at settlement level of District Layyah. Data collection is done by taking water samples from hand pumps and health issues reported at the local health care centers adjoining to that sampling pump. The spatial distribution of Arsenic concentration in groundwater is done by using Inversion Distance Weight (IDW) technique. Arsenic Risk Index (ARI) is developed based of WHO health standards, and then used to divide study area into two Arsenic Risk Zones as no risk and high risk with As values less or equal to 10 ng·ml-1 and greater than 10 ng·ml-1, respectively . In the final step these zones were correlated with the diseases at village level. The results show that, Arsenic is high near the Indus River and it decreases in central and eastern parts towards Chenab River. Same trend of Indo-Chenab Arsenic gradient is followed by skin diseases among the people especially, in tehsil Layyah and tehsil Koror. It is concluded that high Arsenic amount in water and skin diseases are highly dependent on the recharge from Indus River.

Ground water quality near municipal solid waste dumping site at Thirupperumthurai, Batticaloa

Groundwater is a precious natural water resource considered as a readily available and safe source of water for domestic, agriculture and industrial uses. In Sri Lanka, groundwater is being polluted due to various human activities. Improper solid waste management is one of the major sources of environmental pollution deteriorating groundwater quality around landfill sites. In this view, present study was carried out to assess the impact of existing landfill site on groundwater quality at Thirupperunthurai, Batticaloa. In order to achieve this, 20 well water samples around landfill site at different distance were analyzed. Parameters analyzed are pH, EC, TDS, BOD, COD, total hardness, phosphate, nitrate, copper, lead and coliform population. Results revealed that concentration of all the parameters except for pH, are higher than acceptable limits for safe drinking water. The distance from the landfill site also influences on groundwater quality. Overall, the groundwater is highly polluted due to existing landfill site in this study area. Therefore, the relevant authority should take immediate measures to rescue this area. DOI: http://dx.doi.org/10.4038/jas.v10i1.8044 The Journal of Agricultural Sciences, 2015, vol.10, no1: p.21-28

OCCURRENCE OF ARSENIC, LEAD, THALLIUM AND BERYLLIUM IN GROUNDWATER

The occurrence of carcinogenic and heavy metals in groundwater sources in Urban-west region of Zanzibar Island is an issue that is not very well known. This could be also coupled with the absence of drinking water treatment plants. This study for the first time reports on the occurrence and the levels of three carcinogenic metals-Arsenic (As), Beryllium (Be) and lead (Pb) in thirty groundwater samples collected from Zanzibar’s Urban/West region. The levels of alkalinity, Magnesium (Mg) and Thallium (Tl) were also determined. The concentrations of As, Be, TI and Pb in the water samples were determined by the Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Palintest photometry procedures were used to determine the levels of total alkalinity and magnesium. Be, As, Tl and Pb were not detected (nd) in some water samples. The ranges of concentrations of Be, As, TI and Pb in the samples were; nd to 6100 ng L-1, nd to 6600 ng L-1, nd to 11600 ng L-1 and nd to 31400 ng L-1 respectively. The levels of total alkalinity varied from 38 to 380 (mg L-1 as CaCO3). The proportions of water samples contaminated with Be, Tl, As and Pb were 43.3, 66.7, 70 and 96.7% respectively. About 23% of the water samples had Pb concentrations beyond WHO limits for safe drinking water, while 30 and 56.67% of the samples had Be and Tl concentrations beyond the US EPA’s maximum limits. The concentration of arsenic in each water sample was within WHO limits. The occurrence and the levels of carcinogenic metals in water sources could be a potential cause of cancer cases in Zanzibar. Therefore, prompt action is required to control the levels of these hazardous metals, and other possible contaminants in Zanzibar’s domestic water systems.

A Systematic Study of the Chemical Stress Response Induced by Bleach And Vinegar in E. Coli on Viability and Protein Expression Profiles Using Plating Assays And Matrix‐Assisted Laser Desorption Ionization (MALDI) Biotyper™ System

Bacterial water contamination is a serious global public health problem. Even though most mammals carry Escherichia coli (E. coli) in their guts, certain strains can lead to severe ailments of the gastro‐intestinal tract including diarrhea, the second leading cause of death in children under five. While the contamination frequently originates at the water source, water storage conditions can heavily exacerbate the health risk. Here, we present our systematic study of the effects of two ordinary household chemicals, bleach and vinegar, on E. coli viability and protein expression profiles, as a function of chemical concentration, contact time, E. coli density, and incubation temperature, A combination of standard culture plating assays and spectroscopic measurements were used to assess viability and to determine the minimal chemical concentration required to keep bacterial levels below the EPA's safe drinking water limits. Matrix‐assisted Laser Desorption Ionization (MALDI) Biotyper was used to compare the unique molecular fingerprint of E. coli subjected to multiple chemical stress conditions and harvested at different time points. This work represents the initial step in identifying E. coli proteins sensitive to chemical treatment and could provide insights into the mechanism of stress response in E. coli that would be important in developing strategies to overcome bacterial resistance.

Naturally occurring arsenic in terrestrial geothermal systems of western Anatolia, Turkey: Potential role in contamination of freshwater resources

Arsenic (As) contamination in terrestrial geothermal systems has been identified in many countries worldwide. Concentrations higher than 0.01mg/L are detrimental to human health. We examined potential consequences for As contamination of freshwater resources based on hydrogeochemical investigations of geothermal waters in deep wells and hot springs collected from western Anatolia, Turkey. We analyzed samples for major ions and trace element concentrations. Temperature of geothermal waters in deep wells showed extreme ranges (40 and 230°C), while, temperature of hot spring fluids was up to 90°C. The Piper plot illustrated two dominant water types: Na-HCO3− type for geothermal waters in deep wells and Ca-HCO3− type for hot spring fluids. Arsenic concentration ranged from 0.03 to 1.5mg/L. Dominance of reduced As species, i.e., As(III), was observed in our samples. The Eh value ranged between −250 and 119mV, which suggests diverse geochemical conditions. Some of the measured trace elements were found above the World Health Organization guidelines and Turkish national safe drinking water limits. The variation in pH (range: 6.4–9.3) and As in geothermal waters suggest mixing with groundwater. Mixing of geothermal waters is primarily responsible for contamination of freshwater resources and making them unsuitable for drinking or irrigation.

Investigation into the physico-chemical properties and hydrochemical processes of groundwater from commercial boreholes In Yenagoa, Bayelsa State, Nigeria

The physico-chemical and hydrochemical study of commercial borehole waters in Yenagoa, Bayelsa State have been carried out. Eight commercial borehole water samples were analyze for various physico-chemical parameters using standard methods. The results obtained shows that the water samples quality examined compared favourably with WHO (1998) standard for drinking water. Although the values for pH (5.20±0.14, 6.10±0.10, 6.20±0.10, 6.20±0.20 in well 2, 5, 6, and 7 respectively), electrical conductivity (EC) of 520.00±5.50 mS/cm in well 7, biochemical oxygen demand (BOD) of 9.55±0.26 mg/L in well 3, Ca (9.25±0.10, 8.25±0.03 and 7.90±0.10 mg/L in well 2, 3, and 7 respectively) and all values obtained for Fe exceeded the WHO permissible limits for safe drinking water. The concentration of heavy metals; lead, copper, chromium, cadmium and arsenic (major sources of ground water pollution) were below detectable limit except at well 5, 6, and 7 where lead values of 0.03±0.001, 0.008±0.00, 0.04±0.00 mg/L respectively were obtained. The hydrochemical analysis shows that ion exchange and silicate weathering are the major prevailing hydrochemical processes in the groundwater. All the results obtained were however not significantly different from other reported values within the Niger Delta region. The higher concentrations of some of the parameters (pH, Ec, BOD, Fe, Ca 2+ ) and the present of lead in some samples is an indication of some levels of pollution in the boreholes/ground water. This therefore calls for appropriate treatment measures before the consumption of these waters by the populace to avoid long term accumulative health problems of these pollutants. Recommendations on the strategies to reduce/eliminate some of these pollutants were made. Key words: Physico-chemical properties, hydrochemical processes, groundwater, boreholes, Yenagoa.