Potential Groundwater Contamination Research Articles

Saline and hydrocarbon-bearing fluids detected in shallow aquifers of southern New Brunswick, Canada: Natural occurrence, or deep migration along faults and industrial wellbores?

Unconventional hydrocarbon production has sparked public concerns for several years, especially regarding potential potable groundwater contamination by hydrocarbons, brines, and various chemicals related to hydraulic fracturing operations. One possible contamination mechanism is upward migration of deep-seated contaminants over large vertical distances, through preferential pathways such as leaky well casings or permeable geological faults. In New Brunswick (Canada), thermogenic hydrocarbons and brackish water were previously reported in shallow water wells, some of them located close to unconventional gas wells or to major faults, but the exact origin of these fluids remained uncertain. The objective of this paper is to determine whether the presence of these fluids is the result of migration from the deep (>1 km) hydrocarbon bearing units (via natural or anthropogenic migration pathways), or whether they rather originate within the shallow aquifer (<100 m) or from intermediate zone. Tracking fluid origin was achieved by fingerprinting compositional and isotopic values of three indicators: 1) water isotopic signature (including tritium (3H), radiocarbon (14CDIC), δ18OH2O, δ2HH2O), 2) salinity (including Na, Ca, K, SO4, Cl, Br, 87Sr/86Sr), and 3) hydrocarbons (compositional data and δ13CCH4). These various analyses were conducted, when relevant, on samples of different matrices composing the hydrogeological system, namely shallow groundwater (12–90 m depth), shallow bedrock gas (8–131 m), and intermediate zone evaporitic rocks (173–332 m); they were compared with previously published values for deep basin brines and gases (1940–3168 m) from the hydrocarbon bearing Carboniferous Albert Formation. This unique suite of indicators, analytes and matrices allowed drawing the conclusion that thermogenic gas and high salinities present in the sampled wells were naturally occurring and originating from shallow and intermediate-zone bedrock units. Results obtained through this approach did not provide any evidence that hydrocarbon wells in this area have acted as preferential migration pathways for deep-seated fluids towards shallow aquifers.

Biochar obtained from eucalyptus, rice hull, and native bamboo as an alternative to decrease mobility of hexazinone, metribuzin, and quinclorac in a tropical soil.

Mobile herbicides have a high potential for groundwater contamination. An alternative to decrease the mobility of herbicides is to apply materials with high sorbent capacity to the soil, such as biochars. The objective of this research was to evaluate the effect of eucalyptus, rice hull, and native bamboo biochar amendments on sorption and desorption of hexazinone, metribuzin, and quinclorac in a tropical soil. The sorption-desorption was evaluated using the batch equilibrium method at five concentrations of hexazinone, metribuzin, and quinclorac. Soil was amended with eucalyptus, rice hull, and native bamboo biochar at a rate of 0 (control-unamended) and 1% (w w-1), corresponding to 0 and 12 t ha-1, respectively. The amount of sorbed herbicides in the unamended soil followed the decreasing order: quinclorac (65.9%) > metribuzin (21.4%) > hexazinone (16.0%). Native bamboo biochar provided the highest sorption compared to rice hull and eucalyptus biochar-amended soils for the three herbicides. The amount of desorbed herbicides in the unamended soil followed the decreasing order: metribuzin (18.35%) > hexazinone (15.9%) > quinclorac (15.1%). Addition of native bamboo biochar provided the lowest desorption among the biochar amendments for the three herbicides. In conclusion, the biochars differently affect the sorption and desorption of hexazinone, metribuzin, and quinclorac mobile herbicides in a tropical soil. The addition of eucalyptus, rice hull, and native bamboo biochars is a good alternative to increase the sorption of hexazinone, metribuzin, and quinclorac, thus, reducing mobility and availability of these herbicides to nontarget organisms in soil.

Microbial, chemical, and isotopic monitoring integrated approach to assess potential leachate contamination of groundwater in a karstic aquifer (Apulia, Italy)

Landfill sites are subjected to long-term risks of accidental spill of leachate through the soil and consequential contamination of the groundwater. Wide areas surrounding the landfill can seriously be threatened with possible consequences to human health and the environment. Given the potential impact of different coexisting anthropic pollution sources (i.e., agriculture and cattle farming) on the same site, the perturbation of the groundwater quality may be due to multiple factors. Therefore, it is a challenging issue to correctly establish the pollution source of an aquifer where the landfill is not isolated from other anthropic land uses, especially in the case of a karstic coastal aquifer. The present study is aimed at setting in place an integrated environmental monitoring system that included microbiological, chemical, and isotope methods to evaluate potential groundwater pollution in a landfill district in the south of Italy located in Murgia karstic aquifer. Conventional (microbial plate count and physical–chemical analyses) and advanced methods (PCR-ARISA, isotope analysis of δ18O, δ2H, 3H, δ 13C, δ 15N-NO3−, and δ 18O-NO3−) were included in the study. Through data integration, it was possible to reconstruct a scenario in which agriculture and other human activities along with seawater intrusion in the karst aquifer were the main drivers of groundwater pollution at the monitored site. The microbiological, chemical, and isotope results confirmed the absence of leachate effects on groundwater quality, showing the decisive role of fertilizers as potential nitrate sources. The next goal will be to extend long-term integrated monitoring to other landfill districts, with different geological and hydrogeological characteristics and including different sources of pollution, to support the ecological restoration of landfills.

Durability, Capillary Rise and Water Absorption Properties of a Fiber-Reinforced Cement-Stabilized Fly Ash–Stone Dust Mixture

The management of unutilized fly ash poses challenges due to concerns about storage and its potential groundwater contamination. Within the road industry, where the bulk utilization of fly ash is feasible, its unsuitability for use in the base and sub-base layers of pavements due to its low strength and a high proportion of fine particles has been a limitation. The incorporation of stone dust alongside fly ash, treated with lime or cement, yields superior strength and stiffness. Apart from strength, the stabilized mix’s durability, capillary rise, and water absorption properties are crucial for determining its suitability for pavement applications. Observations from this study reveal that fiber-reinforced cement-stabilized fly ash–stone aggregate specimens treated with 4% and 6% cement, with and without fibers, met the limiting mass loss of 20%, as specified in IRC SP: 89. The mass loss decreases with an increase in cement and fiber content. However, the capillary rise in the mixes increases with a higher percentage of fly ash and fiber content but decreases with increased cement content. Cement addition results in a reduction in water absorption; however, the addition of fibers results in an increase in water absorption. A linear correlation has been established between mass loss and UCS and IDT, which can be used to evaluate the suitability of materials for the structural layer without conducting a wet–dry durability test, which typically takes one month. This study proposes that cement-stabilized fly ash and stone aggregate mixtures with 4% and 6% cement can be used as the subbase and base of pavement based on wet–dry mass loss criteria and water absorption criteria. Observations from this study reveal that fiber-reinforced cement-stabilized fly ash–stone aggregate specimens treated with 4% and 6% cement, with and without fibers, met the limiting mass loss of 20%, as specified in IRC SP: 89. The mass loss decreases with an increase in cement and fiber content. However, the capillary rise in the mixes increases with a higher percentage of fly ash and fiber content but decreases with increased cement content. Cement addition results in reduction in water absorption. However, the addition of fibers results in increase in water absorption. A linear correlation is established between mass loss and UCS and IDT, which can be used to evaluate the suitability of materials for the structural layer without conducting wet–dry durability tests, which take one month. This study proposes that cement-stabilized fly ash and stone aggregate mixtures with 4% and 6% cement can be used as the subbase and base of pavement based on wet–dry mass loss criteria and water absorption criteria.

Termite IPM in historic sites

Abstract Given the traditional use of wood, historical structures are susceptible to termite damage which can irreversibly affect their historical significance. Methods like drilling into the foundation for termiticide injection are impractical and potentially harmful to the structural integrity of these structures. Moreover, the location of these structures in ecologically sensitive areas prohibits the use of soil termiticides due to potential contamination of groundwater, rivers, or oceans. Termite Integrated Pest Management (IPM) strategies include baiting programs that use minimal quantities of benign insecticides to reduce environmental impact. This approach is consistent with the risk management component of termite IPM. Bait systems are proven to be effective in eliminating termite colonies, contributing to the benefit component of IPM by preserving the value of historical sites. This article discusses successful baiting interventions at notable locations such as the Statue of Liberty National Monument, New York, USA, the Christiansted National Historic Site in St. Croix, US Virgin Islands, and the Historic Tzu-Su Temple in Taiwan.

Seawater softening by nanofiltration enables ecofriendly Dead Sea level stabilisation while creating the basis for cost-effective inland desalination

Increased water extraction led to accelerated shrinkage of the Dead Sea, seriously damaging the environment and posing an economic risk for industry and tourism. The surrounding countries are willing to avert this looming crisis; however, previous approaches became infeasible due to economic, political and ecological hurdles. Motivated by this issue, we propose an alternative sustainable concept based on nanofiltration. We carried out basic design and cost estimations, showing that nanofiltration permeate produced from seawater allows environmentally friendly Dead Sea recharge, minimising gypsum precipitation, algae blooms and groundwater contamination potential on the conveyance routes. Dead Sea level stabilisation with nanofiltration permeate from Med Sea water costs between 0.54 and 0.7 $/m3 at 7 % weighted average cost of capital, significantly lower than treating Red Sea water (0.76 to 0.86 $/m3). Furthermore, providing NF permeate at the Dead Sea in transboundary exchange with Israel allows Jordanian and Palestinian inland desalination for regional potable water production. In the Jordan case, potable water costs at the major demand center, Amman, range between 1.56 and 1.76 $/m3, significantly lower than the national supply from the Red Sea. This study promises a new, feasible solution for trilateral research and implementation cooperation on the Dead Sea issue.

Microplastics attenuation from surface water to drinking water: Impact of treatment and managed aquifer recharge – and identification uncertainties

River water can be used to recharge aquifers exploited for drinking water production. Several recent studies reported microplastics (MPs) in river water, and therefore, the potential contamination of groundwater by MPs is a growing concern among stakeholders and citizens. In this research, we investigate the fate of MPs (> 20 μm) along six different stages of a major Managed Aquifer Recharge (MAR)-water supply system in Switzerland. About 20 l of water were filtered using steel meshes at each location in triplicates. In the laboratory, MPs deposited on the anodisc filters were identified using Focal Plane Array (FPA) micro-Fourier-Transform-InfraRed (μFTIR) spectroscopy. The obtained hyperspectral data were processed using the imaging software Microplastics Finder for MPs identification and classification. Our results revealed a 20-fold decrease in MPs concentration from the Rhine River bed water (112 ± 27.4 MPs/l) to after the coagulation, flocculation and sedimentation (5.5 ± 2.2 MPs/l), a further 3-fold decrease to after the sand-filtration system (1.8 ± 0.9 MPs/l), corresponding to an overall removal efficiency of 98.4 %. The MPs concentrations remained low following MAR (2.7 ± 0.7 MPs/l) through a Quaternary gravel aquifer. Activated carbon filters did not substantially further reduce MPs concentrations. The percentage of fragments (≈95 %) prevailed over fibers (≈5 %) at all locations, with fibers being longer and more abundant in the river water. Overall, this study demonstrates the effectiveness of the treatment systems to remove MPs larger than 20 μm. Finally, we calculated an uncertainty in MPs concentrations of one order of magnitude depending on the user-defined parameters inside the MPs identification and classification model. The Quality Assurance/Quality Control approach followed during laboratory analysis highlighted an accumulation of surrogate particles at the edges of the disc, which would have an impact for MPs number upscaling.

Design and evaluation of microencapsulation technology to reduce the environmental impact of copper fungicides in vineyards

Grapevine is a relevant crop in the European area, that has been traditionally linked to the use of copper fungicides for downy mildew control (Plasmopara viticola). The continued use among the years of this type of copper fungicides has caused an environmental impact, mainly accumulating copper ions in the soil and also resulting in surface and groundwater pollution. To reduce the amount of copper used in vineyard crop protection strategies, and for instance, the contamination, a microencapsulated copper product has been developed. Deposition trials in artificial vegetation were assessed in order to define the optimal formulation characteristics linked with leaf deposit. Also, field trials in real conditions were performed to compare the newly developed copper product with a conventional one. These studies were completed with an evaluation of the microencapsulated product behaviour into two different soil types and its leaching that can consequently be potential groundwater contamination. Microencapsulated formulation resulted in higher deposition compared to the reference product. The obtained results are a relevant drawing up on a way to reduce the amount of copper used, due to the microencapsulated product having the potential to reduce the amount of copper used in vineyard crop protection and the environmental impact they cause.

Inventory of pesticides and their potential risk of contamination in the semi-arid region of Ceará (Cariri–CE, Brazil)

The present study deals with pesticides, and their potential risk of contamination in the municipalities of the Cariús River micro-watershed (Cariri – CE). In general terms, it aimed to analyze the environmental fragility to the use of pesticides and to identify the active principles used, their respective environmental risks and their process of accumulation, transport and contamination of soil and water, in the area that covers the municipalities of Santana do Cariri, Nova Olinda, Farias Brito and Cariús, located in the south of the state of Ceará. To carry it out, the GUS Index (Groundwater Ubiquity Score) was applied in the active principles of pesticides sold and applied in the region, as in a model suggested by Neves, Gomes and Spadotto (1998), which takes into account the leaching and resulting surface runoff variables, and the natural characteristics (Pedology, hydraulic conductivity, altitude and slope) in the delimitation of areas with natural susceptibility to environmental impacts resulting from the application of pesticides. The results indicated that the entire region is susceptible to contamination caused by the indiscriminate use of pesticides, with great potential for contamination of groundwater and surface water. Due to their high leaching capacity, the following products should be abolished: Connect, Atrazine Nortox 500 SC, Calaris, Nicosulfuron Nortox 750 WG, DMA® 806 BR, Tucson, Quallis, U46, Artys, Aminol, Tordon and Disparo®. Glyphosate, Karate Zeon 50 CS, Klorpan, Pyrinex 480 EC, and Decis 25EC should be avoided or replaced with alternative techniques. It is recommended to diversify the production and promotion of organic agriculture through sustainable agricultural techniques/practices and with lower environmental impacts.

Potential toxic element contamination and non-carcinogenic risk assessment of groundwater from rapidly growing urban areas in Telangana, India.

Groundwater is a critical resource for drinking purposes that is under pressure and polluted with multiple inorganic contaminants. Among various contaminants, potentially toxic element contamination in groundwater has significant public health concerns due to their toxicity at a low level of exposure. This investigation aimed to assess the toxic element contamination and associated non-carcinogenic human health risk at rapidly growing urban centers in Telangana to ensure potable water and to generate baseline data in the study province. Thirteen potential toxic trace elements (Al, As, B, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn) were determined in 35 groundwater samples collected from the Karimnagar and Siddipet smart cities in lower Manair River basin using inductively coupled plasma mass spectrometry (ICP-MS). The trace element concentration is found in the range for Al (1-112µg/L), As (2-8µg/L), B (34-438µg/L), Cd (bdl-2µg/L), Co (bdl-17µg/L), Cr (bdl-4µg/L), Cu (bdl-216µg/L), Fe (4-420µg/L), Mn (bdl-3311µg/L), Ni (5-31µg/L), Pb (bdl-62µg/L), Se (1-18µg/L), and Zn (3-1858µg/L). Analytical data of groundwater revealed the occurrence of toxic elements observed as above the acceptable limits of Bureau of Indian Standards for drinking purposes found in the order of Al > Ni ≥ Mn > Se ≥ Cu ≥ Pb > Fe with 26% > 14% ≥ 14% > 9% ≥ 9% ≥ 9% > 6% of samples, respectively. The non-carcinogenic health risk to humans upon groundwater ingestion has been evaluated and found to be non-hazardous for all the individual elements studied except for aresenic. However, cumulative hazard quotient observed as > 1 in the category of infants and children might be a major potential health concern. This study provided baseline data and suggested implementing preventive measures to protect human health around the urban areas of lower Manair river basin, Telangana, India.

Heavy Metal Transport in Different Drip-Irrigated Soil Types with Potato Crop

Heavy metal (HM)-polluted soil is a serious concern, especially as brackish water is widely used for irrigation purposes in water-scarce countries. In this study, the HYDRUS-2D model was used to simulate HM (copper (Cu), lead (Pb), and zinc (Zn)) transport through agricultural land cultivated with potato crops under surface drip irrigation to explore the potential groundwater contamination risk. Three soil types, namely, silty clay loam, sandy loam, and sandy soil, and two irrigation schemes, irrigation every two days (scheme A) and irrigation every four days (scheme B), were considered during the simulations. Firstly, the ability of HYDRUS-2D to simulate water flow was validated using data obtained from a full growing season of the potato crop in a lysimeter irrigated by surface drip irrigation using El-Salam Canal water, Egypt (i.e., water contaminated by HMs). Secondly, the model was calibrated for solute transport parameters. After that, the investigated simulation scenarios were executed. The results showed that HYDRUS-2D effectively simulated water flow. Moreover, a good agreement between the simulations and experimental results of HM concentrations under the calibrated solute parameters was obtained with R2 values of 0.99, 0.91, and 0.71 for Cu, Pb, and Zn concentrations, respectively. HM distribution is considerably influenced by the HMs’ adsorption isotherm. The results of the investigated scenarios reveal that soil texture has a greater impact on HM concentrations in the simulation domain and on the contamination risk of the groundwater than the irrigation scheme. Under both irrigation schemes, lower HM concentrations were observed in sand, while higher values were observed in silty clay loam. Subsequently, the potential shallow groundwater contamination risk is greater when cultivating potatoes in sand, as higher HM concentrations were found in drainage water compared to the two other investigated soils, regardless of the irrigation scheme. The cumulative Cu, Pb, and Zn concentrations in drainage water corresponding to scheme A for silty clay loam and sandy loam were 1.65, 1.67, and 1.67 and 1.15, 1.14, and 1.15 times higher, respectively, than scheme B. To safeguard the sustainability of groundwater and agricultural lands irrigated with water contaminated by HMs, it is recommended to adopt an irrigation frequency of once every four days in soils with silty clay loam and sandy loam textures.

Potential groundwater contamination from oil drilling in the Okavango

Canadian oil and gas company, Reconnaissance Energy Africa (ReconAfrica), plans to exploit potential oil reserves in the Cubango Okavango River Basin (CORB) in Namibia and Botswana, where little is known about the local groundwater systems and how contamination and its effects could impact the region. Using borehole data from target oil and gas areas, we calculated hydraulic gradients, flow direction, and flow velocity to map potential groundwater contamination effects from oil and gas drilling in the region. We also plotted the major geological structures, calculated flowpaths, and estimated travel times for contaminated groundwater that may travel along these preferential flowpaths from the drill sites to the Okavango River and Delta. Results indicate that contaminated groundwater from the oil lease areas could take 3–23.5 years to reach the Okavango River system via the shallow sandy aquifer, but in a worst-case scenario, contamination could reach the Delta within four days via structures associated with dykes and faults that serve as primary flowpaths. Such contamination could adversely affect human health and the region's ecosystems and biodiversity. We recommend prohibiting oil exploration and production activities within the CORB until future studies can determine the impacts of hydrocarbon extraction with greater certainty.

ANALYSIS OF THE PERCOLATION BEHAVIOR OF PETROLEUM DERIVATIVES IN SANDYSOIL OF THE ALAGOAS COAST

Oil and its derivatives are applied in different ways in society and their commercialization, handling, and disposal raise concerns regarding the potential for contamination of soils and groundwater in cases of spillage. The present work aims to evaluate the behavior of the percolation of petroleum derivatives in sandy areas of the Alagoan coast. This analysis used automotive lubricating oil spill tests to evaluate the effect of viscosity (0w20 – 47.6 cSt, 5w30 – 64 cSt and 20w50 – 134.7cSt) and granulometry in sandy media (Praia do Saco – 3.06 μm in diameter, Cruz das Almas – 5.06 μm in diameter, and Barra de Sao Miguel – 5.47 μm in diameter). While verifying the influence of physicochemical characteristics of the soils, values of the average Sauter diameter, distribution of the sizes of the sediments, and the values of the total saturation (100%) of water were determined for all conditions analyzed. Thus, results show that, after determining the physicochemical characteristics of the soils and the oils applied in the bench tests, the viscosity of the oils and the values of the particle diameters of the sandy soils influence the percolation behavior. This influence was determined by the percolation behavior of the oils in sandy media, because for the analysis in a soil with a diameter of 3.06, the radial percolation was more significant for the oil with higher viscosity (20w50 - 134.7cSt) and in the axial percolation the behavior was more present for the lower viscosity oil (0w20 - 47.6 cSt). That is, in a sandy soil of the same diameter, radial flow increases with increasing viscosity and axial flow with the lowest viscosity. In addition, the radial flow is more expressive in smaller granulometries and the axial flow in larger granulometries for the same viscosity condition. However, it is of fundamental importance to evaluate the front of advance of the contaminants and, thus, to know the extent of the damage, so that the measures of environmental remediation are adopted.

Using Water Stable Isotopes and Cross-Correlation Analysis to Characterize Infiltration of Precipitation through Unsaturated Zone at the Velika Gorica Site of Zagreb Aquifer

The unsaturated zone plays a crucial role in the hydrological cycle and is a key factor in modeling and understanding hydrological processes. It regulates water transfer from the land surface to the groundwater while providing protection, transfer, and attenuation of potential groundwater contaminants. This research presents the first results of continuous in situ monitoring of all soil horizons of the Eutric Cambisols and the remaining unsaturated zone of the Zagreb aquifer (Velika Gorica well field). The Zagreb aquifer is the main source of potable water for the inhabitants of the City of Zagreb and Zagreb County, which is protected by the Republic of Croatia. Cross-correlation analysis and water stable isotopes (δ2H and δ18O) were used to investigate whether there is a hydraulic connection between precipitation and groundwater, the approximate duration of percolation, and whether there are indicators that suggest the presence of preferential flow or processes such as water mixing and/or evaporation. The cross-correlation analysis showed and confirmed the assumption of the presence of preferential flow with average lag times ranging from 1.59 up to 3.63 h. The results also indicate that low organic matter content may contribute to higher lag times associated with precipitation infiltration. It was found that only high-intensity precipitation events allow effective infiltration, and that the amount of infiltration depends on the water content of the soil at the beginning of each precipitation event. The isotopic results showed that the isotopic composition of the soil water in the first three soil horizons follows the one of precipitation, while deuterium excess confirmed that the sampled water is mobile water and that an evaporation process is possible in the A horizon. The results also show that suction cups can be used to determine the isotopic signature of both bulk and mobile water, depending mainly on the granulometric composition of the material in which they are installed.

DRASTIC-Fm-URBAN index: an updated and reliable GIS vulnerability mapping for the assessment of fractured rock media in urban areas

Fractured media hydrosystems sources are valuable worldwide for irrigation, water supply, and industrial purposes. Mapping and evaluating intrinsic groundwater vulnerability is a balanced integrative methodology to describe the potential groundwater contamination or pollution. The Geographical Information System (GIS) overlay mapping technique and multi-parametric methodology are largely employed to evaluate vulnerability in groundwater systems. However, the DRASTIC index methodology is often used for regional approaches and is the most recognised for groundwater vulnerability assessment for general purposes. Therefore, several adaptations were proposed, such as the DRASTIC‐Fm methodology focused on fractured rock media. This study proposes an updated multi-parametric DRASTIC-Fm-URBAN methodology’s concept, importance, and applicability, which supports the potential groundwater vulnerability on fractured media assessment for urban areas. This approach is more accurate, particularly on regional to local scales. The analytic hierarchy process (AHP) was applied to define the weight of each assessment parameter. In addition, the index DISCO-URBAN, SI and GODS were used in the historic springs of the Porto and Vila Nova de Gaia riverside urban area. In fact, coupling DRASTIC-Fm-URBAN and DISCO-URBAN vulnerability indexes are reliable approaches to be included as a tool to develop a robust hydrogeological conceptual site model for urban areas.

The Influence Of Rock Mineralogy On Groundwater In The Kampungbaru Formation,Coal Mining Area, Anggana And Surrounding Area, District. Kutai Kartanegara

Coal mining activities using the open pit mining system method will have impacts, both positive and negative impacts, positive impacts will cause changes in improving socio-economic life, while negative impacts will affect changes in hydrogeological conditions and environmental changes such as increasing soil/rock acidity so that it will cause water contaminated. This condition has an impact on decreasing the quality and quantity of groundwater as a source of clean water. The purpose of this study was to determine the hydrogeological conditions around the study site, and the influence of rock mineralogy as a potential source of groundwater contamination, especially in the Kampungbaru Formation. The methods used to obtain data such as; pumping test, rock mineralogy analysis (knowing the characteristics) by conducting studies; petrography, microscopic analysis of ore, XRD analysis, XRF analysis and analysis of the potential of acid mine water, while knowing the chemical characterization of water by analyzing the concentration of anion cations, and classifying water classes. Knowing the characterization of rock mineralogy and water chemistry, the level/value of potential groundwater contamination in the study area will be known. The hope of this research is to know and understand the characteristics of mineralogy of rocks and groundwater chemistry, as well as hydrogeological conditions in Kampungbaru Formation, so that groundwater contamination can be known. Specific benefits of the research, which is to explore more detail hydrogeology of the mine and surrounding areas, to understand the characteristics of rock mineralogy and the characteristics of groundwater chemistry, and to know the source of groundwater contamination of the research area. Practical benefits can provide information to the public and government about the potential of good quality groundwater around the research area and know the groundwater location of good quality. The results of hydrogeological studies, study of mineralogy characterization and groundwater chemistry will be obtained conclusion such as: 1) Characteristics of aquifer in Kampungbaru Formation included in the category of productive aquifers. 2) Mineralogy of rocks affect the chemical concentration .. 3) Kampungbaru Formation has the content of metal mineral elements and water chemical concentrations that contain many sulphide compounds as acid mine formers. Stratigraphy of the study area is included in the Kampungbaru Formation and is part of the Kutai Basin (Kutai Basin). Lithology The Kampungbaru Formation consists of a rocky outcrop with sandstone with coal insertions and sandstone units.&#x0D; &#x0D; Keywords: Hydrogeology, characteristics of mineralogy and groundwater chemistry, contamination

Characterization of Shiga toxin-producing Escherichia coli presence, serogroups and risk factors from private groundwater sources in western Ireland

Over recent years, Ireland has reported the highest crude incidence rates of Shiga toxin-producing Escherichia coli (STEC) enteritis in Europe. Unregulated private groundwater sources have emerged as an important potential transmission route for STEC, with up to 750,000 Irish residents reliant on these sources for domestic waters. This study aimed to investigate the prevalence and serogroup profile of STEC contamination from domestic private wells in western Ireland. Fifty-two groundwater sources were analysed during two sampling campaigns in the autumn (September/October) of 2019 (n = 21) and 2021 (n = 31). Untreated groundwater samples (30 L) were collected and analysed using the “CapE” (capture, amplify, extract) method. Extracted DNA was tested using multiplex real-time PCR for Shiga toxin stx1 and/or stx2 and eae genes. STEC positive DNA samples were tested for clinically relevant serogroups by real-time PCR. Data relating to 27 potential groundwater contamination risk factors were geospatially linked to each well and assessed for association with E. coli, stx1 and/or stx2 and eae presence/absence. Overall, 20/52 wells (38.4 %) were positive for E. coli (median concentration 8.5 MPN/100 mL as assessed by Colilert-18 method). Stx1 and/or stx2 was detected in 10/52 (19.2 %) wells overall and 8/20 E. coli positive wells, equating to a STEC to “generic” E. coli detection ratio of 40 %. Six of these wells (30 %) were also positive for eae. One or more serogroup-specific gene targets were identified in all but one stx1 and/or stx2 positive sample, with O145 (n = 6), O157 (n = 5) and O103 (n = 4) most prevalent. STEC presence was significantly associated with decreasing well depth (U = −2.243; p = 0.024) and increasing 30-day mean antecedent rainfall (U = 2.126; p = 0.034). Serogroup O104 was associated with increased sheep density (U = 2.089; p = 0.044) and detection of stx1 and/or stx2 + eae with increased septic tank density (U = 2.246 p = 0.023). Findings indicate high detection rates of clinically relevant STEC in E. coli contaminated groundwater sources in Ireland.

Evaluation of the Laboratory Degradation Performance of a Straw Drainage Board

Plastic drainage boards are installed into the foundation as vertical drainage channels in vacuum preloading projects. After construction, numerous plastic drainage boards are left in the foundation, causing not only white pollution but also potential groundwater contamination. Straw was utilized to produce degradable drainage boards in this study, and the feasibility of straw drainage boards was confirmed by laboratory degradation tests. The results revealed that Zhuhai’s soft marine soil is rich in degrading bacteria such as Bacteroidota and Firmicutes, which have adverse effects on the performance of the straw drainage board. The straw drainage board was deteriorated by bacteria in the foundation, and the discharge capacity and tensile strength dropped with time, with the discharge capacity degradation relationship as qw(t) = qw0(1 − 3.83 × 10−6t2). The discharge capacity and tensile strength of straw drainage boards are lower than those of plastic drainage boards, but they all meet the engineering requirements. Straw drainage boards can replace plastic drainage boards in vacuum preloading reinforcement projects, which not only solves the problem of environmental pollution but also expands the comprehensive utilization of straw resources in a new way.

Water vulnerability to pesticide contamination in a Brazilian semiarid watershed.

This study aimed to prepare an inventory of the main active ingredients of pesticides and estimate the risk of pollution of groundwater and surface water resources in a Brazilian semiarid basin. The inventory was prepared using data from government agency databases. The contamination risk estimate was obtained using the GOSS index, Groundwater Ubiquity Score (GUS), Groundwater Screening Index (GSI), Leachability Index (LIX), US Environmental Protection Agency (USEPA) criteria, Leaching Index (LEACH), and Relative Leaching Potential Index (RLPI). The inventory identified 57 active ingredients commercialized under a well-defined chemical class. Most of these (51.5%) belong to the very dangerous class, while 43.6% belong to the moderately toxic class. The GOSS model showed that 23.7% of the active ingredients have a low potential, 50.85% have a moderate potential, and 13.56% have a high potential for surface water contamination, with its transport being associated with the sediment. The GUS index indicates a low potential for groundwater contamination. However, the GSI points to a high potential for water contamination, the USEPA criteria for a possible contamination of groundwater, and, according to the LIX, most of the pollutants do so by leaching. The information provided contributes to the management of xenobiotic compounds in arid and semiarid basins, adding to the water security effort by providing tools for the assessment of potential pesticide pollution. Integr Environ Assess Manag 2023;19:804-816. © 2022 SETAC.

Numerical Analysis of Potential Contaminant Migration from Abandoned In Situ Coal Conversion Reactors

Abstract. In the context of a potential utilisation of coal resources located in the Mecsek mountain area in Southern Hungary, an assessment of groundwater pollution resulting from a potential water-borne contaminant pool remaining in in situ coal conversion reactors after site abandonment has been undertaken in the scope of the present study. The respective contaminants may be of organic and inorganic nature. A sensitivity analysis was carried out by means of numerical simulations of fluid flow as well as contaminant and heat transport including retardation to assess spatial contaminant migration. Hereby, the main uncertainties, e.g., changes in hydraulic gradient and hydraulic contributions of the complex regional and local fault systems in the study area, were assessed in a deterministic way to identify the relevant parameters. Overall 512 simulations of potential groundwater contamination scenarios within a time horizon exceeding the local post-operational monitoring period were performed, based on maximum contaminant concentrations, cumulative mass balances as well as migration distances of the contaminant plume. The simulation results show that regional faults represent the main contaminant migration pathway, and that contamination is unlikely assuming the given reference model parametrisation. However, contamination within a simulation time of 50 years is possible for specific geological conditions, e.g., if the hydraulic conductivity of the regional faults exceeds a maximum value of 1 × 10−5 m s−1. Further, the parameter data analysis shows that freshwater aquifer contamination is highly non-linear and has a bimodal distribution. The bivariate correlation coefficient heatmap shows slightly positive correlations for the pressure difference, the fault permeability and the simulation time, as well as a negative correlation for the retardation coefficient. The results of this sensitivity analysis have been integrated into a specific toolkit for risk assessment for that purpose.