Tellus regional stream water geochemistry: environmental and mineral exploration applications

Regional stream water geochemistry acquired as part of the Tellus programme in Ireland has been analysed to assess its potential for application to environmental assessment and mineral exploration. Interpolated geochemical maps and multivariate statistical analysis, including principal component analysis and random forest classification, demonstrate broad geogenic control of stream water chemistry, with both bedrock and subsoil contributing to the patterns observed. Surface water regulations set Environmental Quality Standard values for individual Priority Substances and Specific Pollutants that may depend on background concentrations and/or water hardness. The high resolution of Tellus stream water data and their location on low-order streams have allowed estimation of background concentrations and water hardness in the survey area, with significant implications for water monitoring programmes. Anthropogenic inputs to stream water in the survey area come mainly from agricultural sources and Tellus data suggest few catchments are unaffected. Comparison of Tellus stream water geochemistry with stream sediment and topsoil geochemistry suggest that stream water geochemistry has strong potential for use in mineral exploration, with the same base metal and gold pathfinder anomalies apparent in all three data sets. Cluster analysis indicates that base metals in stream water are associated with organic matter but statistical analysis may be employed to distinguish mineralization-related signatures.Supplementary material: Comparison of cation/anion associations using Piper plots and principal component analysis is available at https://doi.org/10.6084/m9.figshare.c.5683094Thematic collection: This article is part of the Hydrochemistry related to exploration and environmental issues collection available at: https://www.lyellcollection.org/cc/hydrochemistry-related-to-exploration-and-environmental-issues

Characterization and Modification of Clay for Removal of Drinking Water Hardness

Hardness in drinking water is a major problem in domestic usage. It is important to use drinking water within the tolerance limits of hardness. Clay samples obtained from two different areas in Sri Lanka were analysed, modified, and optimized with a view to suppress the hardness in drinking water. Characterization of clay was carried out using XRD (X-ray diffraction spectroscopy), FTIR (Fourier transformed infrared spectroscopy), and SEM (Scanning electron microscope). Variation of the adsorption capacity of clay was analysed at different firing temperatures of the clay samples. XRD analysis revealed that both clay types are consisting of Kaolinite as the main constituent. The hardness adsorption efficiency and the retention of hardness adsorption in prolonged cycles has been observed when the clay is heated at different temperatures. In addition, the water hardness adsorption efficiency was enhanced by the cationic modification using sodium chloride. The results further reveals that the Freundlich isotherm is best fit for Ca2+ adsorption on both Biyagama and Deniyaya clay whereas that for the Mg2+ adsorption is Langmuir isotherm. The present study is useful to develop low-cost clay-based materials to minimize water hardness.

EFFECTIVENESS ANALYSIS OF SOFTENING METHODS OF WATER FROM NATURAL SOURCES

The results of chemical analysis of natural waters from surface (river, water supply) and underground (well, well) sources are given. Water selection for analysis was carried out in a number of cities and villages of the Samara and Penza regions. The analysis was performed on the following indicators: total stiff ness, hydrogen index, calcium, magnesium, iron cations, chlorides, sulfates, hydrocarbonates, permanganate oxidability. The most common chemical indicator of water quality exceeding MPC was identifi ed. The negative impact of rigid water on the operation of boiler units and household needs is shown. Various methods of water softening are illuminated. The results of determination of water hardness before softening and after fi ltration through a layer of cationite and anionite are presented. Based on the obtained indicators, recommendations are given on the selection of softening methods for various types of boilers.

EFFECTIVENESS ANALYSIS OF SOFTENING METHODS OF WATER FROM NATURAL SOURCES

The results of chemical analysis of natural waters from surface (river, water supply) and underground (well, well) sources are given. Water selection for analysis was carried out in a number of cities and villages of the Samara and Penza regions. The analysis was performed on the following indicators: total stiff ness, hydrogen index, calcium, magnesium, iron cations, chlorides, sulfates, hydrocarbonates, permanganate oxidability. The most common chemical indicator of water quality exceeding MPC was identifi ed. The negative impact of rigid water on the operation of boiler units and household needs is shown. Various methods of water softening are illuminated. The results of determination of water hardness before softening and after fi ltration through a layer of cationite and anionite are presented. Based on the obtained indicators, recommendations are given on the selection of softening methods for various types of boilers.

Bacteriological and Physico-chemical Qualities of Halabja Drinking Water

Water is crucial for all known forms of life without providing any calories or organic nutrients, while many people, especially in developing countries, may not be able to access pure and safe drinking water. They could lose their lives or become sick because waterborne diseases could contaminate the water, and when the chemical and/or physical properties of the water are not within the national and international standards. Thus, the present study aimed to evaluate water quality of the Halabja drinking water and Sirwan river. Halabja city is located to north of Iraq, north-east of the capital Baghdad. Every week of the year 2019, apart from official holidays, water samples were collected from each of river and several areas (4-10 sections) in Halabja for the bacteriological analysis, while chemical and physical water quality was monthly checked. The results showed no detectable waterborne pathogens in all drinking water samples. Additionally, values of pH, turbidity, total dissolved substances, and electrical conductivity of the purified water samples had ranges of 7.97–8.5, 0.02-0.8 NTU, 246–362 mg/L, and 383–566 µS/cm, respectively. The treated drinking water was free of Free Residual Chlorine (FRC) and nitrite. The amounts of chloride, sulfate, and nitrate varied during the year 2019, with ranges of 48.2- 73.8, 36-141.5, and 1-5 mg/L, respectively. The values of water hardness and Ca+2 and Mg+2 concentrations ranged 132- 344, 48–89.5, and 2.2-29.2 mg/L, respectively. Based on the results, values of all the above parameters were within the Iraqi and the World Health Organization (WHO) drinking water standards, although the value of water hardness and the concentration of Ca+2 were near the upper limits of the standards, which might cause harm to the human body.

Purification of Waste Water of Oil-And-Fat Production By Compositions of Reagent-Adsorbents

This article shows the possibility of using reagent-adsorbent compositions, i.e. charred defecate obtained at 600 °C and activated bentonite of the Askamar deposit in a ratio of 1:5. It was found that with the use of reagent-adsorbent compositions it will allow to purify wastewater from oil and fat production to pH-7.2 and transparency of 0.44, and also the water hardness is reduced from 17 mEq / l to 4.0 mEq / l, which allow the recycling of wastewater for technical needs.

Removal of hardness from drinking water by electrocoagulation using iron electrodes

In the present study laboratory studies are carried out to examine the removal of hardness by electrocoagulation process from drinking water using iron rod electrodes in batch mode. The purpose of this study was to investigate the efficiency of EC process in removal of water hardness through iron-rod electrodes in varying conditions. Experimental water sample was taken from water distribution network of local area Pune City, Maharashtra state, India. The indices for calcium and total hardness removal in pH (4.0, 7.0, and 10.0), electrical potential of 12 and 24 V and reaction times of 5 minutes to 30 minutes were measured. The maximum efficiency of hardness removal which was obtained at pH 10.0, voltage of 12 and reaction time of 60 min are equal to 98.5% and 97.5% for calcium and total hardness, respectively. Final pH of remained solution has also increased which rises with acidic pH and decreases in alcoholic pH, so the results demonstrate the direct effect of pH, potential difference and reaction time on hardness removal using EC process.

The Groundwater Geochemistry and the Human Health Risk Assessment of Drinking Water in an Area with a High Prevalence of Chronic Kidney Disease of Unknown Etiology (CKDu), Sri Lanka

Chronic kidney disease of unknown etiology (CKDu) has become an alarming health issue in Sri Lanka. The disease is more notable among farming communities and people who consume groundwater as their main source of drinking water. To assess the possible links between drinking water chemistry and expansion of CKDu, the study was compared with hydrogeochemical data of drinking water sources in a CKDu prevalent area (Girandurukotte GND, Badulla District) and a reference area (Dambethalawa GND, Ampara District) in Sri Lanka. Based on the results, nephrotoxic heavy metal (Cd, Cr, Pb, and As) concentrations were significantly higher in the CKDu prevalent site than the reference area, compromised the harmful consequences to the people in the CKDu hotspot. Results of the inverse distance weighted (IDW) interpolation tool indicated the nephrotoxic heavy metals contents including Cd, Pb, As, and Cr in CKDu hotspot were changed in the ranges of 9.78–187.25 μg/L, 0.08–0.66 μg/L, 20.76–103.30 μg/L, and 0.03–0.34 μg/L. The random distribution patterns were shown by the result in Moran’s index values. Noteworthy, the results have emphasized a strong association between fluoride and water hardness. The frequency of occurrence above the threshold limit of fluoride was 28% in non-CKDu water samples, while 81% in CKDu prevalent sites. The hardness values in the CKDu prevalent site indicated “moderately hard water,” while the non-CKDu area indicated the “soft water.” Furthermore, this paper quantified overall water quality and heavy metal contamination and assessed the human health risks associated with drinking water. According to the results of the water quality index, 90% of the samples in the CKDu prevalent area were classified as “poor water” and “very poor water” for drinking purposes, while 73.33% of the samples in the non-CKDu area were “good” and “excellent” for drinking usage. Calculated chronic daily intake (CDIoral) and hazard quotient (HQoral) of nephrotoxicants were higher in CKDu hotspot than the non-CKDu site. Besides, the hazard index (HI) values obtained for the CKDu prevalent area exceeding the acceptable limit (HI = 1) indicated potential health risks to the people in those areas. This study suggests that long-term exposure to nephrotoxic heavy metals, water hardness, and fluoride present in drinking water may threaten human health and affect kidney functions. Therefore, regular monitoring and better management of water supplies in CKDu prevalent areas are essential to determine the contamination load and reduce the health impacts due to excessive and long-term exposure to the nephrotoxicants.