DRASTIC Approach Research Articles

Assessing groundwater contamination risk in industrial zone of Ranipet district, Southern India: A modified DRASTIC and Fuzzy-AHP approach

Groundwater plays a substantial function in sustaining the water requirements of Ranipet district, Tamil Nadu, India, across a variety of domains, including drinking water, agriculture, and industry. However, rising demand and industrial activities have caused concern about groundwater pollution and susceptibility in the region. So, this study employed a modified DRASTIC model to find the regions that are most vulnerable to groundwater contamination. The model includes a novel parameter, "proximity to industry,” in addition to the seven traditional factors (depth to water level, net recharge, aquifer media, soil media, topography, impact of vadose zone and hydraulic conductivity) to account for the industrial nature of the study region. The fuzzy-analytical hierarchy process (FAHP) was used to compute parameter weights and ratings. All the parameters are overlayed in ArcGIS software to create the groundwater vulnerability map (GWVM). The map revealed that the central area along the Palar River is highly vulnerable to contamination. The southern and northern parts have medium to extremely low groundwater contamination risks. The depth of the water table was the most significant component impacting the vulnerability, as per the sensitivity analysis. The model is further validated by chromium concentrations, which were shown to be high in highly sensitive zones and low in low-risk zones. This study also suggests the need for extensive and periodic groundwater quality assessments in highly vulnerable zones for sustainable water resource management.

Application of modified drastic model for oil spills pollution affecting water quality system in part of Niger delta region of Nigeria

Extensive environmental pollution has affected the water resource, agricultural lands, economy and health of the inhabitants of Ahoada communities of the Niger Delta region, Nigeria. The main sources of pollution are oil spills emanating from pipeline interdiction and production-related spillages. Oil spills in the Niger Delta adversely affects the physical, chemical and biological properties of soil, which subsequently results in food shortages due to the reduction of nutrient contents of soils. Therefore, it is crucial to understand the patterns and the types of contaminants for appropriate remediation of the polluted areas. This study applied a novel DRASTIC model approach, incorporating a data-driven method Weight of Evidence (WoE) to examine subsurface aquifer vulnerability to oil spills contamination and present same as in the maps. Geographic Information System (GIS) in combination with DRASTIC and a modified DRASTIC model called DRAPSTIC were used in assessing the extent and vulnerability of the aquifers of the area to contamination. The maps of the DRAPSTIC show similarity in terms of the distribution and classification of the vulnerability index. Very high and high vulnerability classes covered larger areas in Ahoada east under DRAPSTIC compared to DRASTIC. However, under the same DRAPSTIC, larger areas were covered by low vulnerability class in Ahoada West.

Comparative study of the vulnerability to groundwater pollution by the DRASTIC and SINTACS methods on the Amizour plain (Béjaia, North Algeria)

The present study deals with the vulnerability and the risks of pollution on the Amizour plain aquifer (north Algeria), already threatened by several sources of pollution (e.g., industries, agriculture, illegal dumping, etc.) that collapsed this region, without any planned environmental protection measures. In the aim to study the sensitivity of the Amizour plain against pollution two methods (DRASTIC and SINTACS models) were used and the results were compared and evaluated. The maps showed a similarity in the degrees of vulnerability ranged from high to medium. Most of the plain is affected by a high degree of vulnerability of 76% and 67% as estimated by DRASTIC and SINTACS, respectively. In fact, such remarkable degree is justified by the shallow position of the groundwater and the type of aquifer. The degree of groundwater vulnerability was 18% and 33% in the northern and southern part of the studied zone as estimated by DRASTIC and SINTACS methods, respectively. According to the DRASTIC approach, an area with a very high vulnerability (6%) was observed amidst the Amizour plain. Superimposing both maps of vulnerability and the pollution source sites allowed us through the risk map to frame the areas at high risk of groundwater contamination. This investigation will facilitate to make decisions in implementing of an accurate and urgent management project for safeguarding the studied zone. The applicability of these findings has been discussed and suggestions for attenuating the risk of contamination have been given.

Application of GIS‐based DRASTIC model and its validation with Solute Transport Model in the assessment of groundwater vulnerability index: A case study from coal mining region of India

AbstractThe intensive Coal mining in Dhanbad, India, is crucial for contaminating the groundwater resources. The present work aims to estimate the vulnerability of aquifers to contamination with the aid of a GIS‐based DRASTIC approach. This is finally validated by comparing the concentration of the contaminant computed by the Solute Transport Model. Using the soil moisture flow and pollutant transport model, an effort is made to validate the vulnerability of groundwater pollution. The vulnerability maps showed that some of this region's western southwest, and northern part lies in the highly vulnerable region. The major influential parameters in the present study for mapping the vulnerability are shallow depth to groundwater, higher net recharge and more permeable vadose zone. Furthermore, the surrounding mining activities are highly accountable for depleting groundwater superiority in the present research area. These vulnerability maps can be later on effectively used for environmental development and managing future water resources. The Solute Transport Model does not compute vulnerability; instead, it computes the concentration of the contaminant.

621 Ethical Considerations to Prevent Burns in Patients Who Smoke While Receiving Home Oxygen Therapy

IntroductionHome oxygen therapy (HOT) is prescribed to patients with pulmonary dysfunction as a means of improving survival and quality of life. However, ignition of HOT can lead to burns that carry significant morbidity and mortality. This is especially true for patients who actively smoke while on HOT, with prior studies showing that 87.3% of HOT-related burns were due to smoking. An ethical issue thus arises for providers who routinely treat this patient population: how to balance providing beneficial treatment for a patient with the responsibility to protect that patient from suffering unnecessary burn injuries.MethodsA literature review was conducted to determine the conversations surrounding this ethical dilemma in the scientific community. Thought was given to various solutions to address issues, and each solution was analyzed with respect to the traditional ethical principles of autonomy, beneficence, nonmaleficence, and justice.ResultsMultiple prevention considerations should be made for this patient population of active smokers on HOT. The first is to encourage more judicious prescription of home oxygen. This approach supports the principle of nonmaleficence as utilizing more prudence with prescription may prevent unnecessarily putting a patient at risk. A second strategy would be to discontinue a patient’s HOT if they were found to be an active smoker despite proper education; however, this solution conflicts with beneficence, especially if the patient relies heavily on HOT. A third, more drastic approach would be to withhold treatment of patients who repeatedly present with burns acquired secondary to smoking while on HOT. Refusal to treat conflicts not only with beneficence and maleficence but also with justice, as social factors play into which patients are more likely to smoke and, thus, may present with smoking-related burns while on HOT. Lastly, it is possible to address this challenge with broader, upstream solutions such as more thorough, longitudinal patient education on smoking cessation and the risks of smoking while on HOT. By doing so, physicians support all four of the traditional ethical principles.ConclusionsPatients who suffer from burn injuries secondary to HOT ignition present a unique ethical challenge. Though physicians are tasked with the duty to provide optimal care for these patients, they are also shouldered with the responsibility of patient education and advocacy. Physicians should address this outstanding dilemma by thinking more critically about potential solutions that are bolstered by ethical considerations.

Improving Bambara Groundnut Production: Insight Into the Role of Omics and Beneficial Bacteria.

With the rise in the world population, environmental hazards caused by chemical fertilizers, and a decrease in food supply due to global climate change, food security has become very pertinent. In addition, considerable parts of agriculture lands have been lost to urbanization. It has therefore been projected that at the present rate of population increase coupled with the other mentioned factors, available food will not be enough to feed the world. Hence, drastic approach is needed to improve agriculture output as well as human sustainability. Application of environmentally sustainable approach, such as the use of beneficial microbes, and improved breeding of underutilized legumes are one of the proposed sustainable ways of achieving food security. Microbiome-assisted breeding in underutilized legumes is an untapped area with great capabilities to improve food security. Furthermore, revolution in genomics adaptation to crop improvement has changed the approach from conventional breeding to more advanced genomic-assisted breeding on the host plant and its microbiome. The use of rhizobacteria is very important to improving crop yield, especially rhizobacteria from legumes like Bambara groundnut (BGN). BGN is an important legume in sub-Saharan Africa with high ability to tolerate drought and thrive well in marginalized soils. BGN and its interaction with various rhizobacteria in the soil could play a vital role in crop production and protection. This review focus on the importance of genomics application to BGN and its microbiome with the view of setting a potential blueprint for improved BGN breeding through integration of beneficial bacteria.

Assessment of the vulnerability to contamination of fractured aquifers based on DRASTIC method

Vulnerability map is an effective tool to assess and identify the areas that are most susceptible to groundwater contamination, and can aid in the planning and management of municipal groundwater. These maps can help decision-making regarding land use and cover, pointing out proper sites to rural and/or urban sprawling but also highlighting restrictions for groundwater withdrawal. This paper aims at evaluating the influence of the lineament density (DRASTIC-LD) and the influence of the land use and cover, along with the lineament density, (DRASTIC-LDLU) in the classification of the vulnerability of the Serra Geral Aquifer System. The DRASTIC approach was modified by adding the lineament density. The DRASTIC-LD method showed high (70.73%), moderate (17.04%) and very high (12.17%) vulnerability. The DRASTIC-LDLU method presented high (55.35%), extreme (19.65%), very high (14.66%) and moderate (10.31%) vulnerability. Lineament density and land use and cover had a significant influence on the vulnerability classification. The spatial distribution of vulnerable zones was quite similar to those obtained by applying the original DRASTIC model. However, a significant increase in vulnerability was observed across the study area when the lineament density parameter was added, followed by an even greater vulnerability when the lineaments were inserted together with land use land cover. Inserting these two parameters together provides a more accurate result of vulnerability in fractured aquifers, as it is a more faithful representation of the reality of this system.

A modified approach to quantify aquifer vulnerability to pollution towards sustainable groundwater management in Irrigated Indus Basin.

The quality of groundwater in the study watershed has worsened because of industrial effluents and residential wastes from the urbanized cities; therefore, there is an important need to explore the aquifer vulnerability to pollution for sustainable groundwater management in the Irrigated Indus Basin (IIB). This study proposed a novel methodology to quantify groundwater vulnerability using two fully independent methodologies: the first by reintroducing an improved recharge factor (R) map and the second by incorporating three different weight and rating schemes into a traditional DRASTIC framework to improve the performance of the DRASTIC approach. In the current study, we composed a recharge map from Soil and Water Assessment Tool (SWAT) output (namely SWAT recharge map) with a drainage density map to retrieve an improved composite recharge map (SWAT-CRM). SWAT-CRM along with other thematic layers was combined using weightage overlay analysis to prepare the maps of groundwater vulnerability index (VI). The weight scale (w) and rating scale (r) were assigned based on a survey of available literature, and we then amended them using the analytical hierarchy process (AHP) and a probability frequency ratio (PFR) technique. Results depicted that the region under high groundwater vulnerability was found to be 5-22% using traditional recharge maps, while those are 9-23% using improved SWAT-CRM. The area under the curve (AUC) revealed that groundwater vulnerability zones predicted with SWAT-CRM outperformed the DRASTIC model applied with the traditional recharge map. Groundwater electrical conductivity (EC) was>2500 mS/cm in the high groundwater vulnerability zones, while it was <1000 mS/cm in the low groundwater vulnerability zones. The outcomes of this study can be used to improve the sustainability of the groundwater resources in IIB through proper land-use management practices.

English

The impact of certain unregulated land-use activities harms the quality of water resources and reduces the sufficiency of drinking water in many developing countries. This study aimed to capture the impact of such activities and evaluate the specific groundwater vulnerability using a modified DRASTIC approach. The DRASTIC-LuPa&nbsp;was proposed and implemented for Aba City, Nigeria by incorporating land-use and the impact of pumping layers to the &ldquo;intrinsic&rdquo; DRASTIC parameters. The results of the analysis revealed that the area classified as &ldquo;low&rdquo; was 15 and 79.1% as &ldquo;medium&rdquo; and 5.9% as &ldquo;high&rdquo; vulnerability classes for the DRASTIC. Whereas for the DRASTIC-LuPa&nbsp;model 3.2% for &ldquo;low&rdquo;, 54.3% for &ldquo;medium&rdquo;, 41.8% for &ldquo;high&rdquo; and 0.7% for &ldquo;very high&rdquo; were found. The transitions in the vulnerability classes of areas displaying &ldquo;high&rdquo; and &ldquo;very high&rdquo; found in the DRASTIC-LuPa&nbsp;model represent the impact of urban hotspots observed in the area. This result implies that groundwater protection measures should be implemented in the area designated with &ldquo;low&rdquo; and &ldquo;medium&rdquo; vulnerability classes and used for abstracting clean water for drinking purposes. The proposed model enhances the predictability and guarantees better transferability of the approach in urban settings with similar urban trends. &nbsp; Key words:&nbsp;Drinking water, DRASTIC, groundwater, groundwater vulnerability assessment, Nigeria.

Using intrinsic vulnerability and anthropogenic impacts to evaluate and compare groundwater risk potential at northwestern and western coastal aquifers of Sri Lanka through coupling DRASTIC and GIS approach

Groundwater vulnerability assessment has become a crucial step in successfully protecting groundwater against pollution. An attempt of this study has been made to evaluate groundwater contamination risk using intrinsic vulnerability and land-uses in Vanathavillu, Kalpitiya and Katana area in Sri Lanka, using coupled DRASTIC with GIS as feasible methodology. The findings reveal that the groundwater in the areas under study falls under very low to high contamination risk. The higher risk of contamination has been identified in most of the Kalpitiya (about 82%) with the moderate along the beach in the west and next to Puttalam lagoon in the northeast and southeast. This is mainly due to pollution risk inherent with intense vegetable cultivation, over pumping, shallow groundwater tables and permeable sandy soil. Vanathavillu is under very low to moderate contamination risk, in which the moderate risk (about 13%) has especially been found the center, central southwest and west of the area. The relative less deep groundwater tables, possible seepage from the underlying limestone aquifer and less permeable red earth soil could be cause for the moderate risk in the area. Furthermore, results show that the Katana has low to moderately high groundwater contamination risk. Nitrate has a good agreement with the different pollution risk classes and that nitrate can be used as an indicator of aquifer degradation inherent with land-use activities in the coastal areas. Groundwater quality monitoring network should be set up to minimize the anthropogenic acts, particularly in high and moderate contamination risk zones.

Fuzzy or Non-Fuzzy? A Comparison between Fuzzy Logic-Based Vulnerability Mapping and DRASTIC Approach Using a Numerical Model. A Case Study from Qatar

Vulnerability maps are useful for groundwater protection, water resources development, and land use management. The literature contains various approaches for intrinsic vulnerability assessment, and they mainly depend on hydrogeological settings and anthropogenic impacts. Most methods assign certain ratings and weights to each contributing factor to groundwater vulnerability. Fuzzy logic (FL) is an alternative artificial intelligence tool for overlay analysis, where spatial properties are fuzzified. Unlike the specific rating used in the weighted overlay-based vulnerability mapping methods, FL allows more flexibility through assigning a degree of contribution without specific boundaries for various classes. This study compares the results of DRASTIC vulnerability approach with the FL approach, applying both on Qatar aquifers. The comparison was checked and validated against a numerical model developed for the same study area, and the actual anthropogenic contamination load. Results show some similarities and differences between both approaches. While the coastal areas fall in the same category of high vulnerability in both cases, the FL approach shows greater variability than the DRASTIC approach and better matches with model results and contamination load. FL is probably better suited for vulnerability assessment than the weighted overlay methods.

Progress in carbon capture technologies

Human factors are one of the key contributors to carbon dioxide emissions into the environment. Since the industrial revolution, the atmospheric carbon dioxide levels have increased appreciably. This has been attributed to the utilization of fossil fuels for energy generation coupled with the clearing of forests and extensive manufacturing of some industrial products such as cement. The increase in atmospheric concentrations of carbon dioxide has been widely linked to climate change and the Earth's temperature.A drastic approach is therefore needed in terms of policy formulation to address this global challenge. Carbon capture and storage are reliable tools that can be introduced to the industrial sector to address this issue. Therefore, this review presents a thorough investigation of the various technologies that can be harnessed to capture carbon dioxide. The cost associated with the capture, transport, and storage of the carbon dioxide is discussed. Socio-economic aspects of carbon capture and storage technologies are also presented in this review. Factors influencing public awareness of the technology and perceptions associated with carbon capture and storage should be a point for consideration in future research activities relating to this novel technology. This, in effect, this will ensure effective expert knowledge communication to the general public and foster social acceptance of this technology.

Combining quantity and quality controls to determine groundwater vulnerability to depletion and deterioration throughout South Africa

Groundwater vulnerability is normally associated with the potential for contamination, for example the DRASTIC approach, but the increasing importance of groundwater in human, agricultural, and industrial systems, implies that groundwater vulnerability is dependent on a range of other parameters and particularly parameters impacted by climate change. A robust method for evaluating groundwater vulnerability therefore requires the incorporation of multiple indices into one holistic evaluation. In this study, a model for groundwater vulnerability in South Africa was developed, calculating the combined weighted averages of nine spatial datasets; namely: (1) mean annual precipitation, (2) mean annual surface temperature, (3) tritium distribution in groundwater, (4) potential evaporation, (5) aquifer type and yield, (6) terrain slope, (7) electrical conductivity, (8) population density and (9) cultivated land use. The model was run through 36 different weighting scenarios and indicates that on average 22.4% of South Africa’s groundwater is predicted to have a very high vulnerability to depletion in quantity and deterioration in quality (12.2% very low; 35.4% low; 16.8% moderate and 13.1% high). A single weighting scenario (M-I/C-2/P-2) was chosen that showed good alignment to the previous assessments that predicted that 20.9% of groundwater resources in South Africa have very high vulnerability (1.5% very low; 35.7% low; 24.9% moderate and 17.0% high). The model was adjusted to reflect climate conditions 50 years into the future, resulting in a 3% increase in very high vulnerability areas and a 6% decrease in low vulnerability areas. The results suggest that large areas of South Africa have high groundwater vulnerability, especially in areas where groundwater supplements domestic supply and agriculture. The implementation of this method to evaluate groundwater vulnerability across diverse natural environments and political boundaries will supplement comprehensive groundwater vulnerability assessments and the development of effective groundwater management policy.

Groundwater vulnerability assessment of Hoshangabad and Budni industrial area, Madhya Pradesh, India, using geospatial techniques

The quality of groundwater can be determined by hydrogeological formations which vary geographically. Subsurface geology has significant role in governing the movement and quality of groundwater. The present study aims assessment of groundwater contamination vulnerability in Hoshangabad and Budni industrial area using the DRASTIC model approach. The model is hybridization of the seven parameters that provides input to the model. In the model, rating and weightage to each parameter were assigned as per the relative significance of the parameter in groundwater contamination. Groundwater contamination vulnerability index (GWVI) has been computed by integrating of these data layers in ArcGIS environment. The obtained GWVI in the area varies from 66 to 170, which was further divided into five zones, i.e. (1) very low GW contamination zone, (2) low GW contamination zone, (3) moderate GW contamination zone, (4) high GW contamination zone and (5) very high GW contamination zone. Further, the model has been validated by analysing the sulphide concentration in groundwater of the delineated GW contamination vulnerable zones. The model has been found effective for the prevailing hydrogeological settings of the area. The model can serve as an effective tool for the concerned authority, social workers and government/non-organizations for the management of groundwater resources in the area. Further, application of the GIS technique has been found useful in preparing the database of each variable of the model.

Applying a GIS based DRASTIC Model in the Assessment of Risk to Groundwater Resources Within the Underlying Aquifers in Part of Lagos State, Nigeria

Lagos, Nigeria is one of the megacities in Africa with an estimated annual growth rate of 8%, and its socio-economic growth has continually encouraged influx of people into the city. Hence, this has increased pressure on the underlying water resources with implications for public health and ecological related issues. In this study, anthropogenic induced risk posed to water resources within the underlying aquifers in part of Lagos State, Nigeria, was evaluated using qualitative DRASTIC modelling approach. Geo-hydrological data were acquired for site characterization and setting up of the model. The geology indicated multi-layered aquifer horizons, with extensive lateral lithological variations. The topography ranges between 1.5 and 60 m above mean sea level (amsl). The depth to groundwater is shallow, typically less than 1 m in the south, and a maximum depth of 20 m below ground level, in the north. A vulnerability map was developed from the cumulated sum of the DRASTIC index values. Anthropogenic activities within the study area were super-imposed on the vulnerability map to generate a risk map. The results show that 1% of the study area is designated as High-Vulnerability-High-Risk area. Also, High-Vulnerability-Medium-Risk and Medium-Vulnerability-High-Risk constitute 3% each of the area, while 16% and 25% were designated as Medium-Vulnerability-Medium-Risk and Low-Vulnerability-Medium-Risk, respectively. Although, based on the DRASTIC input parameters, approximately 75% of the area is designated as high and medium vulnerability, however absence of risk activities suggests no risk is posed to the underlying groundwater resource in approximately 52% of this delineated subarea.

Evaluating Antimycobacterial Screening Schemes Using Chemical Global Positioning System-Natural Product Analysis.

Most of the targeted discoveries in tuberculosis research have covered previously explored chemical structures but neglected physiochemical properties. Until now, no efficient prediction tools have been developed to discriminate the novelty of screened compounds at early stages. To overcome this deficit, a drastic novel approach must include physicochemical properties filters provided by Chemical Global Positioning System-Natural Product analysis (ChemGPS-NP). Three different screening schemes GSK, GVKBio, and NIAID provided 776, 2880, and 3779 compounds respectively and were evaluated based on their physicochemical properties and thereby proposed as deduction examples. Charting the physiochemical property spaces of these sets identified the merits and demerits of each screening scheme by simply observing the distribution over the chemical property space. We found that GSK screening set was confined to a certain space, losing potentially active compounds when compared with an in-house constructed 459 highly active compounds (active set), while the GVKBio and NIAID screening schemes were evenly distributed through space. The latter two sets had the advantage, as they have covered a larger space and presented compounds with additional variety of properties and activities. The in-house active set was cross-validated with MycPermCheck and SmartsFilter to be able to identify priority compounds. The model demonstrated undiscovered spaces when matched with Maybridge drug-like space, providing further potential targets. These undiscovered spaces should be considered in any future investigations. We have included the most active compounds along with permeability and toxicity filters as supplemented material.

The relationship between obesity and other medical comorbidities

IntroductionPrevalence of obesity is increasing at an alarming rate, fast becoming a global menace, and been associated with long-term comorbidity disease and the obese are more fold likely to develop these chronic diseases. MethodologyA prospective cross sectional study that employed a self-administered questionnaire of 17 medical comorbidity lists from Charlson Comorbidity Index CCI. The aim was to show the relationship between obesity and other medical comorbidities among 86 patients visiting Hospital Universiti Sains Malaysia HUSM. Patient self-reported outcome was used to obtain history of chronic diseases. Descriptive and one-way ANOVA test was used to show demographic data and the relationship between obesity and other medical comorbidities respectively. ResultsThe association detected by the study between the mean difference of BMI among the comorbidity groups was not significant, F(3, 82) = 0.82, P–value = 0.489, however, the mean BMI of patients in the “Severe-category” 34.8(S.D = 4.66) was higher than in the None-category mean: 32.10(SD = 12.38), implying that the patients in the “Severe-categories” are more obese and have more severe comorbid conditions. ConclusionThe trend showed a relationship between obesity and medical comorbidities in which patients with higher BMI are associated with more comorbid condition. However, a more drastic approach and further researches are needed to ensure adequate weight loss therapy to checkmate chronic illnesses.

A GIS-based modified DRASTIC approach for geospatial modeling of groundwater vulnerability and pollution risk mapping in Korba district, Central India

Intensive use of fertilizers in the agricultural lands and a swift-flying of coal and allied industries in Korba district, India in an unprecedented manner has led to groundwater contamination. Accordingly, an integrated modified DRASTIC and risk index model combined with other statistical techniques are applied to evaluate groundwater susceptibility and pollution risk in the region. The ArcGIS based spatial distribution map of the DRASTIC vulnerability index (DVI) reveals that the high (63%) and very high (23.61%) vulnerable zones identified in DVI map are reduced to that of 57.86% and 17.74%, respectively, when compared with pollution risk map. Results of sensitivity analysis, i.e., map removal sensitivity analysis and single parameter sensitivity analysis confirms that amongst seven DRASTIC parameters the net recharge parameter is the most influencing parameter in view of the groundwater contamination. The linear correlation coefficient (r = 0.89) obtained between risk index values and NO3 concentrations alongside nearly 75% of the study area comprises of agricultural lands and forest/tree clad area corresponds to high to very high risk contamination zones reveal the model validation in the light of the influence of anthropogenic contamination factor in these zones. Furthermore, elevated iron concentration also supports the certain influence of geogenic contamination within the study area. In essence, this study can be effectively utilized in the planning and management of precious groundwater resources in high to very high vulnerable and risk zones of the study area, for its overall sustainable development.

Optimizing the DRASTIC vulnerability approach to overcome the subjectivity: a case study from Shabestar plain, Iran

Due to the seasonality of Shabestar plain rivers, most of the water demands for agricultural and drinking sectors are provided from groundwater. The existence of agricultural activities has expanded the use of chemical and animal fertilizers that are possible to infiltrate and contaminate the groundwater resources. The purpose of this study is to provide an optimized DRASTIC approach for assessing the vulnerability of the Shabestar plain aquifer located in East Azarbaijan Province, North West of Iran. The effective parameters in this method include the depth to groundwater, net recharge, aquifer media, soil media, impact of the vadose zone, topographic slope, and hydraulic conductivity, which are being provided in seven layers in the ArcGIS software environment. After ranking each of the input parameters and applying their equivalent weight coefficients, the DRASTIC vulnerability index for the study area ranged between 53.3 and 118.3. Nitrate concentration values at 66 water wells were used for the validation of the DRASTIC-based vulnerability maps. The r value between the DRASTIC indices and the concentration of nitrate is 0.38 indicating a low correlation. Sensitivity analysis results showed that the impact of the vadose zone and aquifer media is significant on the intrinsic vulnerability of the study area. The Wilcoxon rank-sum test (WRST) was used for rate modification. Also, the weights of the DRASTIC approach were optimized by using the ant colony optimization (ACO) and genetic algorithm (GA). All optimized models increased the r compared to the typical DRASTIC method. The results indicate that WRST and GA methods were most successful for optimization of the rates and weights, respectively, where the WRST-GA-DRASTIC model obtained an r of 0.63.

Assessing perched aquifer vulnerability using modified DRASTIC: a case study of colliery waste in north-east England (UK)

DRASTIC is a commonly used approach for delineating areas that are vulnerable to contamination. This study examines the suitability of DRASTIC for evaluating the vulnerability of groundwater inside a colliery spoil-heap to contamination. The standard DRASTIC approach was modified according to the environmental conditions of spoil heaps that introduce contaminants to the environment. The parameter layers used in DRASTIC are depth to water, net recharge, aquifer media, soil media, topography, impact of the vadose zone and hydraulic conductivity. The values of the hydrogeological parameters used in DRASTIC were obtained from eight exploration boreholes drilled in a spoil heap in Northumberland, England (UK). The estimated DRASTIC vulnerability score was then mapped. Sensitivity analysis of the DRASTIC parameters and validation were implemented. The results indicated that, contrary to the DRASTIC assumptions, the contaminants were not introduced at ground surface, but instead were mainly initiated in the soil, vadose and aquifer zones. Consequently, these zones should receive high values of DRASTIC weights and rates. Zones characterized by low permeability and low recharge represent contaminant hot spots inside the spoil heap, and both parameters in these areas should also receive high values of weights and rates. Sensitivity analysis revealed that the soil, vadose zone, aquifer media, hydraulic conductivity and net recharge are the most controlling parameters with respect to vulnerability. The produced vulnerability map has a high degree of compatibility with the measured contaminant concentrations in the spoil. Thus, the standard DRASTIC approach should be modified before its application to mining waste spoil heaps.