Potential Groundwater Pollution Research Articles

Optimized fertilization using online soil nitrate data

Abstract. A new soil nitrate monitoring system that was installed in a cultivated field enabled us, for the first time, to control the nitrate concentration across the soil profile. The monitoring system was installed in a full-scale agricultural greenhouse setup that was used for growing a bell pepper crop. Continuous measurements of soil nitrate concentrations were performed across the soil profile of two plots: (a) an adjusted fertigation plot, in which the fertigation regime was frequently adjusted according to the dynamic variations in soil nitrate concentration, and (b) a control plot, in which the fertigation was managed according to a predetermined fertigation schedule that is standard practice for the area. The results enabled an hourly resolution in tracking the dynamic soil nitrate concentration variations in response to daily fertigation and crop demand. Nitrate–nitrogen (N–NO3) concentrations in and below the root zone, under the control plot, reached very high levels of ∼ 180 ppm throughout the entire season. Obviously, this concentration reflects excessive fertigation, which is far beyond the plant demand, entailing severe groundwater pollution potential. On the other hand, frequent adjustments of the fertigation regime, which were carried out under the adjusted fertigation plot, enabled control of the soil nitrate concentration around the desired concentration threshold. This enabled a substantial reduction of 38 % in fertilizer application while maintaining maximum crop yield and quality. Throughout this experiment, decision-making on the fertigation adjustments was done manually based on visual inspections of the soil's reactions to changes in the fertigation regime. Nevertheless, it is obvious that an algorithm that continuously processes the soil nitrate concentration across the soil profile and provides direct fertigation commands could act as a “fertistat” that sets the soil nutrients at a desired optimal level. Consequently, it is concluded that fertigation that is based on continuous monitoring of the soil nitrate concentration may ensure nutrient application that accounts for plant demand, improves agricultural profitability, minimizes nitrate down-leaching and significantly reduces water resource pollution.

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.

Long-term vinasse application enhanced the initial dissipation of atrazine and ametryn in a sugarcane field in Tucumán, Argentina.

The production of sugarcane bioethanol generates large volumes of vinasse, an effluent whose final disposal can produce an environmental impact that is of concern. The long-term disposal of vinasse in sugarcane fields could challenge crop management, such as the performance of traditional herbicides, by changing soil properties. This study aimed to evaluate the effect of long-term vinasse application on the field and the dissipation of atrazine and ametryn herbicides in a subtropical sugarcane agroecosystem, and to discuss the potential processes involved in it. Vinasse affected soil properties by increasing pH (12%), electrical conductivity (160%), and soil organic carbon (25%) at 0-10 cm depth of soil. Differences in the herbicide calculated sorption coefficient (Kd) varied according to the pedotransfer function applied and the herbicide type (atrazine or ametryn). During the first seven days after herbicide application, the soil underwent long-term vinasse application and increased atrazine and ametryn dissipation 45% and 33%, respectively, compared with the conventional fertilization scheme (control). The Pesticide Root Zone Model revealed that dissipation was mediated mainly by the degradation process rather than transport or other processes. The long-term application of vinasse in a typical sugarcane field of Tucumán, Argentina decreased the potential groundwater pollution of triazines and, adversely, reduced their bioavailability for weed control. For this, the present study presents original information about how long-term treatment with vinasse may require an adaptation of conventional management practices such as the application of herbicides in Argentina and other sugarcane-producing regions. Integr Environ Assess Manag 2024;20:1075-1086. © 2023 SETAC.

Elemental composition of salt and vulnerability assessment of saline groundwater sources selected based on ethnoarchaeological evidence in Romania

The study aimed to evaluate the elemental composition of salt extracted from shallow to saline groundwater sources selected based on ethnoarchaeological evidence in the Eastern Carpathians and Sub-Carpathians area of Romania and to assess their specific vulnerability using groundwater pollution potential (DRASTIC and DRASTIC-LU methodology). 198 saline water samples were collected from different site types, including natural saline springs, catchment saline springs, brine wells, salted lakes and ponds, during the period between 2007 and 2019. Scanning electron microscopy with energy-dispersive X-ray spectroscopy was employed to characterize the elemental composition of salt after dry-evaporating a predetermined volume of each collected sample. The results indicated that the salt concentration in the brines ranged from 0.1% to 41.3%, with the highest concentration found in wells and natural saline springs. The dominant component was sodium chloride, but several sites had high concentrations of potassium chloride, which is essential for human health. Over 95% of the analyzed samples also contained other minerals like calcium and magnesium, further highlighting the health benefits of these brine sources. However, two sites were slightly contaminated with heavy metals, posing potential health risks if consumed. The DRASTIC index, a standardized system for evaluating groundwater pollution potential, gave scores between 99 and 208, indicating moderate to very high intrinsic pollution potential. Similarly, the DRASTIC-LU index, which takes into account and the land use aspects, showed scores ranging from 114 to 258, suggesting low to very high vulnerability to contamination. These findings provide valuable information on the elemental composition of salt and the vulnerability of these brine sources, which are still used by rural communities for traditional practices like meat and fish preservation, milk curdling, and pickling. The study has important implications for sustainable management from both ethnoarchaeological and economic perspectives.

Cigarette butt pollution in popular beaches of Morocco: Abundance, distribution, and mitigation measures

Cigarette butts pose a significant challenge in managing solid litter, with an estimated 4.5 trillion of them being discarded into the environment annually. This study investigated the pollution of eleven beaches along the Moroccan Mediterranean by cigarette butts compared to other types of marine litter between 2018 and 2023. Sampling was conducted using the visual survey technique according to a standardized protocol. A total of 50, 575 items were collected with cigarette butts (14.62 %) and plastic caps/lids drinks (10.93 %) being the most common. Our survey of eleven beaches revealed 7395 cigarette butts, giving an average density of 0.06/m2 comparable to other countries in the Mediterranean. The analysis of the results shows significant differences in the abundance cigarette butts according to the beach typology, seasonality, sediment type, and number of beach users. Moreover, the study discovered a decrease in beach pollution during the COVID-19 pandemic lockdown, resulting in less litter collected compared to pre- and post-pandemic periods. The Cigarette Butt Pollution Index was categorized as very low pollution in M'diq and Kaa Asrass, low pollution in Ksar Sghir, Fnideq, Amsa, Oued Laou, significant pollution in Martil and Nador and sever pollution in Saidia and Sababia. The CBPI was higher during summer and winter, significantly associated with the density levels of beach users. The study recommends immediate action by the local administration to prevent the potential pollution of groundwater and sand by toxic substances leached from cigarette butts.

Retention and loss pathways of soluble nutrients in biochar-treated slope land soil based on a rainfall simulator

Global food crisis makes intense agricultural activity necessary, which accelerates soil degradation and increases pollution risk to nearby catchments. Application of biochar can effectively retain plant-required nutrients in soils. However, the linkage between retention and loss pathways of nutrients is still unclear, particularly at slope lands. Therefore, a simulated rainfall experiment (rainfall intensity ​= ​50 ​mm ​h−1) was conducted in a sandy soil with 10° gradient slope (indoor experiment) to clarify loss pathways of soluble C, N, P and K in biochar-amended soils. Wood biochar pyrolized at 300 ​°C (LWB) or 600 ​°C (HWB) was applied at 1% (LWB1; HWB1) or 2% (LWB2; HWB2). Our results show that the pathways for C, N, P and K loss was percolation ​> ​surface runoff ​> ​soil erosion. Compared to control, HWB2 treatment had a 2–4 times higher infiltration amount but 5–6 times lower surface runoff and soil loss, indicating that this treatment alleviated nutrient loss via erosion and runoff in the sloped soil. Among all treatments, HWB2 treatment was the most effective for retaining organic C, dissolved organic C, total N, and exchangeable K through various pathways. However, a substantial amount of soluble P was lost through percolation. Therefore, the potential pollution of groundwater by P through percolation pathway should be considered during biochar application.

Urban areas as sources of the groundwater contaminants N,N-dimethylsulfamide (N,N-DMS) and 1,2,4-triazole

Urban pollution from biocides used in building materials has raised emerging concern within recent years. The evidence that the use of biocides can pollute urban groundwaters is very limited, but in Denmark, the common degradation product from the two fungicides tolylfluanid and dichlofluanid, N,N-DMS, is particularly abundant in groundwater within urban areas, which suggests an urban source in addition to its well-known agricultural sources. In addition, another widespread groundwater pollutant, 1,2,4-triazole, may originate from the fungicides propiconazole and tebuconazole, that are also used in outdoor paint and wood protection products. To study the potential pollution of groundwater from fungicides used in outdoor paint and wood protection products, we surveyed concentrations in groundwater in two urban areas, we tested leaching from facades and soil concentrations close to facades and fences, and in lab-experiments, we determined the fate of N,N-DMS and 1,2,4-triazole under different redox conditions in soil sampled down to 7 m below surface.Shallow urban groundwater contained up to 1 μg/L N,N-DMS with concentrations of 0.1–0.3 μg/L below a typical Danish residential area. Despite a phase-out of tolylfluanid and dichlofluanid in paint in 2015, both compounds still wash-off wooden facades and fences and was detected in soil next to the treated wood. Much higher soil concentrations, however, were found for propiconazole and tebuconazole and their common degradation product 1,2,4-triazole, reflecting the fact that they are still in use in outdoor paint and wood protection products. 1,2,4-Triazole also leached to groundwater, but concentrations decreased sharply with depth, probably due to degradation that occurred at all tested soil depths and redox conditions. N,N-DMS, on the other hand, was not degraded in deeper soil layers or under anoxic conditions. Consequently, N,N-DMS may persist in groundwater below populated areas well into the future.

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.

Quantifying the contribution of ecological water replenishment on aquifer recovery using a refined groundwater model.

Due to its independent control and directly easy operation, ecological water replenishment (EWR) has been an important measure for restoring river ecosystems. However, the positive and negative contribution of the EWR activities to aquifer system are not fully understood under the combined influences of climate change and human activities across time scales. A refined groundwater flow model integrating an open channel flow at daily time scales is developed in a part of Northern China Plain to reproduce the dynamic process of groundwater level changes. After model calibration with groundwater level and runoff data, the changes of simulated groundwater level and river runoff have the Nash-Sutcliffe efficiency coefficient of 0.98 and 0.60, respectively. Results clearly demonstrate that the impulse response of aquifer recovery to runoff in three centralized EWRs. By using with and without EWR method, the simulated maximum contribution of EWR near river to aquifer recovery may be over 70 %. Scenario analysis method considering different precipitation, groundwater exploitation reduction and EWR activities are applied to evaluate the total quantities of aquifer recovery. The prediction of nine-year EWR activities under multiple scenarios shows that the increased groundwater level generally varies from 4.08 to 8.57 m, and the contribution of EWR accounts for 7.88 %-36.59 %. It is also noticed that 14 out of the 18 informal landfill sites will face potential groundwater pollution risks, indicating the negative influences of long-term EWR activities. This study can provide a method for quantifying the influences and contribution of EWR on aquifer recovery and can be referred to as a guideline for EWR evaluation with similar hydrogeological conditions.

Specifying the hydrogeological parameters range for a groundwater flow model in El-Qaa Plain aquifer, Sinai, Egypt

Hydrogeological parameters are very uncertain to specify in the groundwater flow models. Hence, it is important to specify a range for these parameters to be further utilized by the groundwater model users. In El-Qaa Plain, previous researchers have determined the hydrogeological parameters such as transmissivity, hydraulic conductivity, and mean annual recharge rate using geophysical methods, pumping tests, hydrological models, and groundwater flow models. However, they are also limited to specific locations and do not spatially distribute. In this paper, an effort has been accomplished to specify a specific range for the aquifer hydrogeological parameters using inverse groundwater modeling taking into account the spatial heterogeneity. These ranges could be taken into consideration during modeling groundwater flow. Hence, a finite-difference groundwater flow model has been applied using the ModFLOW model. Regularized pilot points method (RPPM) has been chosen as an inverse modeling technique to specify the accurate values of the aquifer parameters. Model-independent parameter estimation and uncertainty analysis (PEST) has been utilized to estimate the parameters. The results show that the geometric mean of the hydraulic conductivity in the study area ranges from proximity 1 to 2 m/day. Additionally, the geometric mean of the transmissivity ranges from nearly 200 to 500 m2/day. A relationship between the mean annual recharge rate and hydrogeological parameters has been determined. Besides, maps have been generated showing the spatial heterogeneity of the hydraulic conductivity. These maps could be further utilized by groundwater flow modelers to predict the potential of groundwater flow and pollution in the future.

Potential environmental pollution and human health risk assessment due to leachate contamination of groundwater from anthropogenic impacted site

One of the consequences of landfill systems is the emission of leachate, which is capable of causing contamination of the surrounding environment, including groundwater. Considering three major abandoned landfills in an urban area in Nigeria, the potential environmental pollution due to leachate generated from landfills and human health risk assessment of nearby groundwater were examined using laboratory standards (APHA 2012). The result revealed that the landfills' leachate pollution index (LPI) is 18.84, 19.57, and 19.66, indicating potential pollution of the environment, including groundwater and soil. Conformity of groundwater indicated that Arsenic (Ar-0.0001), Cadmium (Cd-0.002), Zinc (Zn-0.02), Barium (Ba-0.03), Manganese (Mn-0.05), Copper (Cu-0.02, 0.012), Chromium (Cr-0.006, 0.007), and Cobalt (Co-0.03, 0.015) are within the WHO permissible limit while Nickel (Ni-0.06) and Lead (Pb-0.05) exceeded the permissible limit. Using the USEPA model for human health risk assessment, the Total Hazard quotient (THQ) for ingestion and derma exposure indicated that the heavy metals have ≤1 across the three landfills, indicating that the exposed population experience no significant health risk. The THQ trended as Cd>Co>Zn>Ba>Mn>Cu>Cr>Ni>As>Pb for children across all the landfills. The estimation for Total Carcinogenic Risk (TCR) for carcinogenic metals (As, Cd, Cr, Ni, and Pb) from various landfill indicated no carcinogenic risk (TCR <10−6). Although the abandoned landfills showed potential environmental pollution and contamination of groundwater; however, the health risk assessment of the groundwater revealed no significant carcinogenic risk to the population exposed to it. Hence, the need for water treatment and evaluation of the soil contamination status of landfills.

Isotopic signature of anthropogenic sources of groundwater contamination with sulfate and its application to groundwater in a heavily urbanized and industrialized area (Upper Silesia, Poland)

Isotopic signatures of anthropogenic sulfate sources within the Upper Silesian urban area (southern Poland) were investigated to increase the reliability of the origin assessment of groundwater contaminants. To analyze δ34S and δ18O in sulfate, 64 samples were collected, representing several sulfate sources: synthetic and organic fertilizers, raw and treated wastewater, mine water, leachate from landfills, mine heaps, and industrial waste dumps. Additionally, 10 surface water samples were taken from contaminated rivers regarded as potential groundwater pollution sources. Results of δ34S and δ18O in sulfate derived from anthropogenic sources were compared with literature data, which indicated significant discrepancies for some contamination sources. The results were applied to assess SO42- origin in groundwater samples from the Gliwice aquifer. Apart from the δ34S and δ18O data, the study included measurements of major ions, inorganic nitrogen forms, trichloroethene and tetrachloroethene in groundwater. Isotopic analyses of river water samples confirmed the impact of urbanized and industrialized areas on surface water pollution and possible influence on groundwater contamination. The values of δ34S and δ18O similar to wastewater were reported for most groundwater samples from the Gliwice carbonate aquifer. Groundwater contamination was also manifested by higher values of electrical conductivity and concentrations of chloride, sodium, trichloroethene and tetrachloroethene. The comparison of recent isotopic data on SO42- sources with literature values clearly shows that it is very important to investigate local potential contamination sources to increase their reliability in determining the source of groundwater or river water pollution.

Groundwater Quality Assessment Using Groundwater Quality Index and Multivariate Statistical Methods and Human Health Risk Assessment in a Coastal Region of the Vietnamese Mekong Delta

This study aimed to evaluate the suitability of groundwater for drinking purposes and assess the associated human health risks for different age groups in a coastal province of Mekong Delta, Vietnam. Twenty groundwater samples were collected in Soc Trang Province, and various water quality parameters were analyzed. The data were employed to calculate entropy-weighted groundwater quality index (EWQI), principal component analysis (PCA), cluster analysis (CA), and non-carcinogenic and carcinogenic risks for adult and children health. The results revealed that groundwater in some locations, especially in GW19, was polluted by hardness, total dissolved solids, NH4+, Cl-, Fe, total coliform, and E. coli. In addition, 5 principal components from the PCA results could explain 84.5% of the total variation of groundwater quality, which also suggested that the potential groundwater pollution sources were geochemical processes, agricultural activities, domestic and industrial wastewater, seawater intrusion, and excessive nitrogen fertilizer application. The CA results showed that monitoring locations can be divided into 4 clusters based on their similarities in groundwater quality, and the most polluted group was found at cluster IV (GW19). The computed EWQI values ranged from 20.05 to 738.52, with approximately 45% of total samples classifying good to excellent water quality. The sampling points with undrinkable quality are mainly located in the northeast and center of the province. The ratio of children and adults under the threat of adverse health effects due to drinking groundwater contained non-carcinogenic substances (NH4+, NO2-, NO3-, Cd, Cu, F-, Mn, and As) ranged from 5 to 40%, and children had higher risks compared to adults. Additionally, the consumption of As-contaminated groundwater also poses carcinogenic risks for children, female and male adults ranging from 4.80×10-6 to 1.33×10-4. The findings of this study can provide helpful information for policymakers in the development of long-term water management strategies to protect community health.

Modelling hydrogeological parameters to assess groundwater pollution and vulnerability in Kashan aquifer: Novel calibration-validation of multivariate statistical methods and human health risk considerations

Modeling and Investigation on pollution potential of aquifers is a matter of importance in terms of management, development and land-use allocation as well as quality monitoring, pollution prevention and groundwater protection. The purpose of this study is to calibrate and modeling the methods used for pollution potential assessment, in which the impact and apportionment of hydrogeological parameters on groundwater pollution of an aquifer located in Kashan is considered. To do so, Analytic Hierarchy Process (AHP) and fuzzy-statistical analysis methods are used for weighting, ranking and standardize the parameters based on research awards of experts and Ad-Hoc systems. This was performed in such a way that the level and importance of each class of classification parameters is considered equal to the final model, and is equivalent to the reclassified class of indices of groundwater quality and human health risk to nitrate pollution. After ranking and standardizing the parameters as well as final model by using fuzzy-statistical approach, the process of weighting the parameters is accomplished with aid of AHP and Factor Analysis-weighted Principal Component Analysis (FA-PCA) methods based on their apportion and impact on groundwater pollution in addition to their correlation with nitrate map. In addition to the correlation with the standardized nitrate concentration, techniques of the root mean square error (RMSE) and coefficient of variation (COV) are employed to validate the model. The results illustrated that parameters of net recharge, soil media, impact of vadose zone, hydraulic conductivity and aquifer media have created the highest apportion and impact on groundwater pollution. In addition, it was found that weight of these parameters for calibrated and validated model of GPPI (groundwater pollution potential index) is proved to be 8.5, 3.4, 3.3, 2.6, 2.2, for GPRI (groundwater pollution risk index) as the best model is 4.4, 3.7, 3.1, 2.9, 1.1, and it is 4.8 for the land use layer, respectively. Weighting procedure was conducted by FA-PCA approach and following considerations were used; R = 73, RMSE = 1.08 and COV = 20%. Moreover, based on these models with better calibration-validation than generic model, it was found high pollution potential in western margin, high pollution risk in the central parts to the western margin, while it was observed not to have that very high pollution potential and risk in Kashan aquifer.

Hygienic assessment of the population risk due to consumption of water contaminated by pesticides recommended for the protection of potato plants

Widespread use of xenobiotics – chemical compounds that do not have natural biogeochemical cycles, annually leads to contamination of agricultural soils in Ukraine. Water contaminated with chemicals can cause allergic diseases, metabolic disorders, pathology of the respiratory, cardiovascular systems and cancer. The purpose. Hygienic assessment of the population risk due to consumption of water contaminated by pesticides recommended for the protection of potato plants. Materials and methods. Prediction of possible migration of studied pesticides into groundwater was carried out taking into account the rate of destruction of pesticides in soil (τ50), the coefficient of sorption by organic carbon and solubility in water by the index of potential leaching, index of potential pollution of groundwater and surface water(GUS), SCI-GROW – screening concentration in groundwater. Result. The results of the risk assessment showed that the values of the maximum possible daily intake of test pesticides with water (0.027-2.2740 μg/day) are significantly lower than the allowable daily intake of test substances (120-6000 μg/day), taking into account the results of field studies Ukraine and other European countries. The results indicate a relatively low risk to humans due to the inflow of water contaminated with pesticides of the studied groups. Conclusions. 1. High risk of groundwater pollution in soil and climatic conditions of Ukraine by studied herbicides, insecticides and fungicides according to GUS – index of potential leaching into groundwater, which should be taken into account when using them in the chemical protection system and solving monitoring studies. 2. Based on the risk assessment for the population, a relatively low risk for humans due to the inflow of water contaminated with pesticides of the studied groups. 3. This indicates the need to take into account the migration process of most of the studied pesticides in addressing the issue of monitoring studies in soil and water.

The Impact of Rapid Urban Growth on Potential Groundwater Pollution in Ngemplak Sub-District, Sleman District

Ngemplak Sub-District is one of the administrative regions in Sleman Regency which has experienced quite intensive urban development. Based on several studies, this region experienced a fairly rapid change in landuse. This landuse changes has resulted in pressure on the natural resources in this region, especially water resources. The study aims to develop a strategy to maintain the sustainable function of land resources in the midst of massive land changes in Ngemplak Sub-District. This research uses landuse comparative method at two different times to identify rapid urban growth. Whereas to identify potential groundwater pollution, this research uses the GOD method which is use three parameters, they are groundwater occurrence (G), overall aquifer class (O), and depth to water table (D). Based on the results of data processing, there was an increase in built-up area in Ngemplak Sub-District from 2006 to 2015 amounting to 235. 58 hectares. This increase in built-up area is a trigger factor for the emergence of environmental problems, namely the exploitation of water resources found in this region. Based on the results of data processing using the GOD method, the overall potential groundwater pollution in the Ngemplak Sub-District is included in the extreme class.

Evaluation of groundwater vulnerability to pollution using DRASTIC, composite DRASTIC, and nitrate vulnerability models

Background: Groundwater protection against pollution is a very important issue. Groundwater vulnerability maps are useful tools for protecting aquifers and assessing the potential for contamination. Therefore, the purpose of this study was to prepare vulnerability maps and perform sensitivity analysis to identify the most influential factors in the vulnerability of the studied aquifer. Methods: In this study, groundwater vulnerability to pollution was evaluated using DRASTIC, composite DRASTIC, and nitrate vulnerability (NV) models. Drastic is an index for the systematic assessment of potential groundwater pollution. In this method, the drastic index was calculated from the total weight and rank of the factors. For this purpose, first the factors affecting the pollution transfer, were weighted, ranked, and merged using GIS software. Then, using the overlapping techniques and after applying the necessary weight coefficients on each layer, a map of the vulnerability area of the study aquifer was prepared. Results: It was revealed that there is a significant linear relationship between all three models with the distribution of nitrate concentration. Accordingly, it was the most efficient NV model, followed by the composite DRASTIC (CD) and DRASTIC models, respectively. Also, in the studied aquifer, the DRASTIC index was between 147 and 136, the combined DRASTIC index was between 70 and 190, and the nitrate index was between 13 and 132. Conclusion: Vulnerability assessment of the studied aquifer using DRASTIC, and combined DRASTIC, and NV indices shows that, according to the DRASTIC index, 69.7% of the studied aquifer was in the medium vulnerability class. Also, according to the combined DRASTIC index, the largest area (53.62%) has low vulnerability and 31.56% has moderate vulnerability. But according to the nitrate index, 77.16% of the aquifers had very low vulnerability.

A GIS-based groundwater pollution potential using DRASTIC, modified DRASTIC, and bivariate statistical models.

The objective of the current study is groundwater vulnerability assessment using DRASTIC, modified DRASTIC, and three statistical bivariate models (frequency ratio (FR), evidential belief function (EBF), and weights-of-evidence (WOE)) for Sari-Behshahr plain, Iran. A total of 218 wells were sampled for nitrate concentration measurement in 2015. Datasets were generated using results from 109 wells having nitrate concentrations greater than 50 mg/L. The nitrate data were divided into two groups of 70% (76 locations as training dataset) for modeling and 30% (33 locations as a testing dataset) for model validation. Finally, five groundwater potential pollution (GPP) maps were produced by the training dataset and then evaluated using the testing dataset and receiver operating characteristic (ROC) method. Results of the ROC method showed that the WOE model had the highest predictive power, followed by EBF, FR, modified DRASTIC, and DRASTIC models. Results of the maps obtained revealed that high and very high pollution potential covered the southern part of the study areas, where big cities are located. Results of the present study can be replicated in other locations for identifying groundwater contaminant prone areas.

Penilaian Zona Kerentanan Air Tanah Terhadap Pencemaran dengan Metode SINTACS di Ranai (Pulau Bunguran)

Bunguran Besar Island in the Natuna Islands, Riau Islands Province, is dominated by a lowland topography with a sloping to steep morphological condition. In general, the plains on the island of Bunguran Besar have a plains topography with altitudes ranging from 5- 30 meters above sea level, and the highest altitude is on Mount Ranai, 920 meters above sea level. This condition causes environmental problems, especially on the plains that form basins with geodes that affect the condition of easily polluted groundwater resources influenced by the presence of shallow and close to the surface groundwater (aquifer). The condition of the aquifer, which is shallow and relatively close to the surface, has the potential for groundwater contamination by polluting sources. This study aims to determine the potential spatial groundwater pollution using the SINTACS method hydrogeological approach based on this background. The SINTACS method is a vulnerability approach by assigning a value and weight to each parameter or triggering the vulnerability. The primary data used for the vulnerability assessment were phreatic groundwater depth, soil texture, and slope. Meanwhile, the parameters of the infiltration conditions, the aeration conditions of the rocks, the compiler of lithology, and the hydraulic conductivity (K) or the passing of water in the rock were obtained from the secondary data approach. The scenario of groundwater pollution vulnerability uses the normal scenario impact approach. It is known that the condition of low vulnerability is 28% or an area of 486 km 2 , medium vulnerability is 20% or an area of 343.8 km 2 , high vulnerability is 0.04% or an area of 0.7 km 2, and very high vulnerability is 52% or an area of 898.7 km 2 . In general, the condition of vulnerability in Bunguran Besar Island is very high.

Outlook for the coal industry and new coal production technologies

Outlook for the coal industry and new coal production technologies