Remedial Plan Research Articles

The Anthropogenic Footprint of Physical Harm on the Seabed of Augusta Bay (Western Ionian Sea); A Geophysical Investigation

Augusta Bay is an embayment of the Hyblean sector in south-eastern Sicily (Southern Italy) that faces the Ionian Sea and includes the Rada di Augusta, a wide littoral sector sheltered by breakwaters, which hosts intense harbor activities. Rada di Augusta and the adjacent Priolo embayment were listed in the National Remediation Plan (NRP) by the Italian Ministry of Environment, as they have suffered major anthropic impacts over the last seventy years. Indeed, extensive petrochemical and industrial activities, military and commercial maritime traffic, as well as agriculture and fishery activities, have resulted in a highly complex combination of impacts on the marine environment and seafloor. In this paper, we investigate the extent of human-driven physical impacts on the continental shelf, offshore of Rada di Augusta, by means of Multibeam echosounder, Side-Scan Sonar and Chirp Sonar profilers, as well as direct seabed samplings. At least seven categories of anthropogenic footprints, i.e., anchor grooves and scars, excavations, trawl marks, targets, dumping trails, isolated dumping and dumping cumuli, mark the recent human activities at the seafloor. The practice of dredge spoil disposal, possibly protracted for decades during the last century, has altered the seafloor morphology of the central continental shelf, by forming an up-to-9 m-thick hummocky deposit, with acoustic features noticeably different from those of any other shelf lithosome originated by natural processes. All available data were reported in an original thematic map of the seafloor features, offering an unprecedented opportunity to unravel sediment facies distribution and localization of anthropogenic disturbance. Finally, the shelf area was ranked, based on the coexistence of multiple stressors from human-driven physical harm, thus providing a semi-quantitative analysis of environmental damage classification in the area.

Retention of PFOS and PFOA Mixtures by Trapped Gas Bubbles in Porous Media.

The transport of per- and polyfluoroalkyl substances (PFAS) in soil and groundwater is important for site investigation, risk characterization, and remediation planning. The adsorption of PFAS at air-water interfaces has been shown to significantly contribute to PFAS retention, with subsequent effects on concentrations and the time scales of transport. In this study, column experiments were conducted to investigate the transport of perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and 6:2 fluorotelomer sulfonate (6:2 FTS) individually and in binary mixtures in the presence of a trapped gas phase, using clean sands to isolate adsorption to air-water interfaces. Consistent with previous studies, the transport of PFOS, PFOA, and 6:2 FTS was retarded by adsorption at the air-water interface, with greater retention of PFOS due to its higher affinity for the air-water interface. Chromatographic separation occurred in the experiments using binary mixtures of PFOS and PFOA, with greater retention at lower influent concentrations. The mixture experiments also showed enhanced breakthrough of PFOA in the presence of PFOS, where effluent concentrations of PFOA were temporarily greater than the influent concentration prior to the breakthrough of PFOS. This enhanced breakthrough was attributed to competition between PFOS and PFOA for adsorption to the air-water interface.

Microplastic/nanoplastic toxicity in plants: an imminent concern.

The toxic impact of microplastics/nanoplastics (MPs/NPs) in plants and the food chain has recently become a top priority. Several research articles highlighted the impact of MPs/NPs on the aquatic food chain; however, very little has been done in the terrestrial ecosystem. A number of studies revealed that MPs/NPs uptake and subsequent translocation in plants alter plant morphological, physiological, biochemical, and genetic properties to varying degrees. However, there is a research gap regarding MPs/NPs entry into plants, associated factors influencing phytotoxicity levels, and potential remediation plans in terms of food safety and security. To address these issues, all sources of MPs/NPs intrusion in agroecosystems should be revised to avoid these hazardous materials with special consideration as preventive measures. Furthermore, this review focuses on the routes of accumulation and transmission of MPs/NPs into plant tissues, related aspects influencing the intensity of plant stress, and potential solutions to improve food quality and quantity. This paper also concludes by providing an outlook approach of applying exogenous melatonin and introducing engineered plants that would enhance stress tolerance against MPs/NPs. In addition, an overview of inoculation of beneficial microorganisms and encapsulated enzymes in soil has been addressed, which would make the degradation of MPs/NPs faster.Graphical

High-resolution 3D geological modelling of heterogeneity in poorly exposed glacial deposits using sedimentary and glaciotectonic architectural element analysis: a case example from Sellafield in west Cumbria, UK

Three-dimensional modelling of superficial geology is challenging, particularly for complex industrial sites such as the Sellafield nuclear site, Cumbria, UK. A lithostratigraphic approach is sufficient to show distribution of key units where only a general understanding of hydrogeology is required. For many sites, however, a much higher-resolution understanding is needed to better characterize heterogeneity and identify potential pathways for contaminant transport within safety case development and remediation planning. Models that focus on often thin, laterally discontinuous, heterogeneous sedimentary units are beset with issues including (1) a lack of exposure coupled with a dearth of data gathered by low-intrusive and intrusive means, (2) structural, stratigraphic and sedimentological complexities making correlation between data points difficult and (3) uncertainties associated with data quality. However, these problems may be overcome by combining land-system-based sedimentary and glaciotectonic architectural analysis of local field analogues with the creation of a portfolio of generic unit-bounding surface geometries. We test this through the development of a high-resolution 3D geological model of Sellafield nuclear site, where exposures are sparse, but shallow site-investigation boreholes are many. The results demonstrate that land-system-based sedimentary and glaciotectonic architectural element analysis can be applied to capture substantial subsurface heterogeneity resulting from dynamic glacial processes.

Treatment of refractory Helicobacter pylori infection: A new challenge for clinicians.

Patients who have failed two or more attempts to eradicate Helicobacter pylori are commonly referred to as refractory. Although the incidence of refractory Helicobacter pylori infection is only 10-20%, with the increasing rate of antibiotic resistance in various regions, the treatment of refractory Helicobacter pylori infection has gradually become a difficult problem faced by clinicians. When choosing a rescue therapy, the physician must consider numerous factors. A longer treatment duration, higher doses of proton pump inhibitors (PPIs), or the use of potassium-competitive acid blocker (P-CAB) may increase the efficacy of triple therapy or bismuth quadruple therapy. Rescue treatment based on bismuth quadruple therapy usually achieves better results. At the same time, treatment based on drug susceptibility tests or genotypic resistance is recommended where available. Of course, appropriate empiric treatment can also be selected according to local drug resistance, a patient's previous medication history and compliance. It is the best choice if it can improve the success rate of the first treatment and reduce the occurrence of refractory Helicobacter pylori infection. This review aims to summarize the articles related to refractory Helicobacter pylori in recent years and to explore a better remedial treatment plan for clinicians.

Influence of Pedagogy on the Epistemological Estimation of Electrical Engineering Subject

Abstract : COVID-19 pandemic has brought sudden changes in teaching and learning process compared to conventional face to face mode of education all around the globe. During social distancing in pandemic environment, the most common change that has been introduced was to opt online and hybrid mode of learning using e-resources by students and faculty at several organizations. In our organization, the BlackboardTM platform has been used to teach the course either in e-learning or blended mode. The present work is an epistemic case study of an electrical engineering subject taught in blended mode to undergraduate students. The performances of the students have been analysed in continuous assessment as well as in final assignment. The analysis criteria was based on expected “course learning outcomes” taken from ABET guidelines which was planned before the commencement of academic semester. In this case study, a specific part of the final assignment in which a questionnaire was framed to assess the “Understanding”, “Apply”, “Analyzed”, “Evaluate” and “Create” levels of Bloom's Taxonomy by determining the correlation factor among various parameters. It was observed that students had felt the difficulty in achieving the satisfactory response in “Evaluate” and “Create” while performed well in first three levels of Bloom's Taxonomy. Based on analysis and results, it is concluded that to achieve satisfactory response of the students, continuous hands-onexperience of laboratory experiments and instruments are essential. In the coming months when it is difficult to start the face to face mode of teaching and learning, an alternate method for laboratory could be catered by introducing virtual laboratory and simulations. In addition a remedial plan has to be prepared to enhance the critical thinking of the students to improve the “Evaluate” and “Create” levels of students. Keywords ABET; Blended learning; Bloom's Taxonomy; Correlation Coefficients; Epistemology.

Study on simultaneous inversion groundwater pollution sources and aquifer parameters based on bilevel programming

Groundwater pollution source identification is the first step of groundwater remediation planning and an important link of groundwater pollution source identification. In order to make the inversion result more accurate, the bilevel programming is proposed to test its availability. In this paper, iterative time, optimization algorithm and noise level are used to test the accuracy of bilevel programming. The advantages and disadvantages of genetic algorithm, multi-objective genetic algorithm and simulated annealing algorithms are compared in searching optimal decision variables. The results show that the combination of multi-objective genetic algorithm and bilevel programming has better accuracy and robustness. The bilevel programming can be used to identify the groundwater pollution source and aquifer parameters.

Modeling of Water Losses in Hydraulic Tunnels under Pressure Based on Stepwise Regression Method

In this paper, we presented a methodology for efficient and accurate modeling of water losses in hydraulic tunnels under inside internal water pressure, based on multiple linear regression (MLR). The methodology encompasses all steps needed to obtain an adequate mathematical relation between total water losses and relevant measurements in the tunnel, such as reservoir water level, piezometric levels, concrete and water temperatures, size of cracks, etc. Once the data are preprocessed and input variables were chosen, correlation analysis and PCA (principal component analysis) reduction were performed in order to obtain the pool of regression functions. Through an iterative process, according to stepwise regression principles, the most adequate MLR model in terms of accuracy and complexity was chosen. The methodology presented has been validated in modeling water losses in the hydraulic tunnel under the pressure of PSHPP “Bajina Bašta” in the Republic of Serbia. The obtained results have shown significantly better accuracy compared to the results published by other authors, proving that the developed model can be used as a powerful tool in future analyses of tunnel losses and remediation planning.

Assessment of groundwater quality from some hostels around Kwame Nkrumah University of Science and Technology

Groundwater is regarded as a safe source of drinking water because it usually contains low microbial loads often requiring very little or no treatment before drinking. This study investigates water quality, health risks and the major factors controlling the water quality within the study area. From the results, the pH was acidic with a mean value of 5.646 ± 0.389 and an observed range of 5.02 to 6.35. Total dissolved solids and electrical conductivity concentrations were below the permissible limit of the World Health Organization (WHO). The presence of total and faecal coliforms bacteria in some of the boreholes strongly indicates likely microbial contamination and that pathogens may be present. The mean levels of heavy metals were in a decreasing order (mg/L) of Fe (0.323 ± 0.316) > Ni (0.088 ± 0.045) > Pb (0.079 ± 0.034) > Cr (0.06 ± 0.038) > Zn (0.048 ± 0.042) > Cu (0.031 ± 0.022). The levels of Cu, Cr, Fe, Pb and Ni exceeding the WHO limit suggest that groundwater from selected Hostels is unsuitable for drinking. Although most of the analysed heavy metals did not pose any severe health risks via ingestion route, HQdermal of Pb was >1 for children. The estimated hazard index of Cu, Ni, Cr, Pb, Fe and Zn via dermal and ingestion route were <1. Moreover, Cr surpassed the carcinogenic risk limit of 10−6 to 10−4. Multivariate analysis revealed three components accounting for 83.955% of the total variance in the groundwater samples. Principal component analysis revealed anthropogenic (i.e., agricultural and urban runoff) and geogenic activities as the possible sources of pollution within the study area. This study is significant for formulating the needed remediation plans to enhance water quality within the study area.

A Phenomenological Study of Teachers' Perception of Implementing remedial Instruction in an Online Distance Learning

The study explored the lived experiences and perceptions of the teachers at the university in implementing remedial instruction in online distance learning. The study participants are elementary, senior high school, and junior high school teachers who have been part of the new normal, online distance learning. The researchers used purposive sampling to recruit 10 participants. Strategies used to address study credibility include verbatim transcription and saturation of data. Then it was coded and analyzed for patterns and themes to identify the essence of participants' perceptions. The study revealed that implementing remedial instruction in online distance learning had brought challenges and obstacles to both teachers and students adapting to the new setup. The study recommends that the school administration must establish a strong remedial instruction enabler such as additional compensation, mental health, and spiritual support to the teachers and, at the same time, must provide a standardized remedial plan for the students. Doing so will lessen the extra loads of the teachers. It will help the struggling learners improve their academic performance, and most importantly, bringing this will help the gap between the students, teachers, and administration.

Contribution the Failure Mode Analysis and Criticality Evaluation Method to the Rehabilitation of Cork Oak (Quercus suber) Forests in Forest Massif of Tlemcen (Algeria)

The controling of forest sustainability and preforest ecosystems in achieving stability of forest ecosystem require the identification of biophysical indicators, anthropological, and technological. The significant degradation of Quercus suber formations in forest massif of Tlemcen (Algeria) are imposed by both climatic factors, the fires, the overgrazing land, anthropogenic aggression as well as by ineffective management. The making of a reference matrix would make possibility the identification of probable hazards and risks. This study aimed to identify the understanding how the mode of operation of a system to identify failures and treat, and the create the intention of eliminating or minimizing the associated risks. This matrix will consist of relevant indicators which easy guide to estimate and following the understanding of the forest degradation process in Algeria. The FMECA method allowed identification of 20 main defective targets which be grouped into 3 categories namely: technical, ecological, organizational, and facilitate of remediation. Each error can be scored and action plans can be prioritized, allowing different with all forest sector players to better understand the degradation of this natural space in order to implement efficient and appropriate remediation plans.

Chronic toxicity, bioavailability and bioaccumulation of Zn, Cu and Pb in Lactuca sativa exposed to waste from an abandoned gold mine

Abandoned mines with untreated waste cause environmental pollution. The complex mixture of mining waste includes high metal content, anthropogenic chemicals and sterile rocks. Adverse effects of contaminated soils have been widely assessed by the use of plants. The aim of this study was to assess the chronic toxicity of a contaminated soil by waste from an abandoned gold mine on Lactuca sativa and its relationship with the bioavailability and bioaccumulation of Zn, Cu and Pb. Soil samples were taken from the site of mining waste stacking and a reference site in La Planta (Argentina). Contamination indices were calculated and acute and chronic exposures on L. sativa were carried out. Phytotoxicity indices, morphological and biochemical parameters, and concentrations of Zn, Cu and Pb in pseudo total and bioavailable soil fractions and in plant tissue were determined. Concentration- and time-dependent toxicity effects were observed, especially on plant width, fresh aerial biomass, leaf area and percentage of plants with completely necrotic aerial biomass. High levels of Zn (1453.3 ± 220.3 μg g−1) were found in plant tissue compared to Pb (277.2 ± 18.0 μg g−1) and Cu (255.3 ± 25.6 μg g−1). Toxicological endpoints correlated with metal uptake and mining waste concentration. In addition, bioaccumulation factors correlated with mobilisable and water soluble fractions. The concentration of Pb in aerial biomass surpassed the permissible concentrations in leaf vegetables, even at the reference site, indicating that lettuce crop consumption could be risky for the local population's health. This study demonstrated a strong relationship between metal bioavailability, toxicity endpoints and bioaccumulation, contributing with novel information to future ecotoxicological risk assessments and remediation plans.

Recent progress of catalytic methane combustion over transition metal oxide catalysts.

Methane (CH4) is one of the cleanest fossil fuel resources and is playing an increasingly indispensable role in our way to carbon neutrality, by providing less carbon-intensive heat and electricity worldwide. On the other hand, the atmospheric concentration of CH4 has raced past 1,900 ppb in 2021, almost triple its pre-industrial levels. As a greenhouse gas at least 86 times as potent as carbon dioxide (CO2) over 20 years, CH4 is becoming a major threat to the global goal of deviating Earth temperature from the +2°C scenario. Consequently, all CH4-powered facilities must be strictly coupled with remediation plans for unburned CH4 in the exhaust to avoid further exacerbating the environmental stress, among which catalytic CH4 combustion (CMC) is one of the most effective strategies to solve this issue. Most current CMC catalysts are noble-metal-based owing to their outstanding C–H bond activation capability, while their high cost and poor thermal stability have driven the search for alternative options, among which transition metal oxide (TMO) catalysts have attracted extensive attention due to their Earth abundance, high thermal stability, variable oxidation states, rich acidic and basic sites, etc. To date, many TMO catalysts have shown comparable catalytic performance with that of noble metals, while their fundamental reaction mechanisms are explored to a much less extent and remain to be controversial, which hinders the further optimization of the TMO catalytic systems. Therefore, in this review, we provide a systematic compilation of the recent research advances in TMO-based CMC reactions, together with their detailed reaction mechanisms. We start with introducing the scientific fundamentals of the CMC reaction itself as well as the unique and desirable features of TMOs applied in CMC, followed by a detailed introduction of four different kinetic reaction models proposed for the reactions. Next, we categorize the TMOs of interests into single and hybrid systems, summarizing their specific morphology characterization, catalytic performance, kinetic properties, with special emphasis on the reaction mechanisms and interfacial properties. Finally, we conclude the review with a summary and outlook on the TMOs for practical CMC applications. In addition, we also further prospect the enormous potentials of TMOs in producing value-added chemicals beyond combustion, such as direct partial oxidation to methanol.

Evolution and Prospects in Managing Sewage Sludge Resulting from Municipal Wastewater Purification

Municipal sewage sludge is the residual material produced as a waste of municipal wastewater purification. It is a sophisticated multi-component material, hard to handle. For many years, it has been landfilled, incinerated, and widely used in agriculture practice. When unproperly discharged, it is very polluting and unhealthy. The rapidly increasing global amount of municipal sewage sludge produced annually depends on urbanization, degree of development, and lifestyle. Some diffused traditional practices were banned or became economically unfeasible or unacceptable by the communities. In contrast, it has been established that MSS contains valuable resources, which can be utilized as energy and fertilizer. The objective of the review was to prove that resource recovery is beneficially affordable using modern approaches and proper technologies and to estimate the required resources and time. The open sources of information were deeply mined, critically examined, and selected to derive the necessary information regarding each network segment, from the source to the final point, where the municipal sewage sludge is produced and disposed of. We found that developed and some developing countries are involved with ambitious and costly plans for remediation, the modernization of regulations, collecting and purification systems, and beneficial waste management using a modern approach. We also found that the activated sludge process is the leading technology for wastewater purification, and anaerobic digestion is the leading technology for downstream waste. However, biological technologies appear inadequate and hydrothermal carbonization, already applicable at full scale, is the best candidate for playing a significant role in managing municipal sewage sludge produced by big towns and small villages.

Feasibility Assessment of the Application of Groundwater Remediation Techniques in Rural Areas: A Case Study of Rural Areas in the Soutpansberg Region, Limpopo Province, South Africa

Groundwater contribution towards human health and livelihood depends on the contaminants level in groundwater. Many people in rural communities are being exposed to waterborne diseases resulting from drinking untreated contaminated groundwater. This study argues that the lack of implementation of available groundwater remediation methods and associated high costs are exposing rural communities to health risks. This study assessed 22 years of groundwater quality data from 12 boreholes and 2 springs to understand the contaminants level in the Soutpansberg region. A feasibility assessment of the application and design of a sustainable groundwater remediation technique was carried out based on individual- and community-based groundwater remediation types. The assessment considered groundwater management, cost and risk of theft and damage to infrastructure model for rural settings. This study determined that groundwater was not suitable for drinking purposes in some parts due to high concentration levels of NO3− and F−. The feasibility assessment indicated that community-based groundwater remediation schemes are more sustainable in rural areas when compared to individual household remediation. In this study, it is recommended that groundwater remediation plans must be included in any proposed water supply or drought intervention project in rural communities.

The movement ecology of fishes.

Movement of fishes in the aquatic realm is fundamental to their ecology and survival. Movement can be driven by a variety of biological, physiological and environmental factors occurring across all spatial and temporal scales. The intrinsic capacity of movement to impact fish individually (e.g., foraging) with potential knock-on effects throughout the ecosystem (e.g., food web dynamics) has garnered considerable interest in the field of movement ecology. The advancement of technology in recent decades, in combination with ever-growing threats to freshwater and marine systems, has further spurred empirical research and theoretical considerations. Given the rapid expansion within the field of movement ecology and its significant role in informing management and conservation efforts, a contemporary and multidisciplinary review about the various components influencing movement is outstanding. Using an established conceptual framework for movement ecology as a guide (i.e., Nathan et al., 2008: 19052), we synthesized the environmental and individual factors that affect the movement of fishes. Specifically, internal (e.g., energy acquisition, endocrinology, and homeostasis) and external (biotic and abiotic) environmental elements are discussed, as well as the different processes that influence individual-level (or population) decisions, such as navigation cues, motion capacity, propagation characteristics and group behaviours. In addition to environmental drivers and individual movement factors, we also explored how associated strategies help survival by optimizing physiological and other biological states. Next, we identified how movement ecology is increasingly being incorporated into management and conservation by highlighting the inherent benefits that spatio-temporal fish behaviour imbues into policy, regulatory, and remediation planning. Finally, we considered the future of movement ecology by evaluating ongoing technological innovations and both the challenges and opportunities that these advancements create for scientists and managers. As aquatic ecosystems continue to face alarming climate (and other human-driven) issues that impact animal movements, the comprehensive and multidisciplinary assessment of movement ecology will be instrumental in developing plans to guide research and promote sustainability measures for aquatic resources.

Application of the complementary ensemble empirical mode decomposition for the identification of simulation model parameters and groundwater contaminant sources

Identification of groundwater contaminant sources (GCSs) relies on actual observed data, and the observed data directly affects the accuracy of the identification results. However, the observed data inevitably contains noise due to accidental and systematic errors, and the identification results of GCSs based on the observed data containing noise are usually not reliable. This seriously restricts the rational design of contamination remediation plans and contamination risk assessment. To solve this problem, complementary ensemble empirical mode decomposition (CEEMD) was applied to the joint identification of simulation model parameters and GCSs information in this study for the first time. The wavelet analysis and CEEMD methods were used to reduce the noise in observed concentrations respectively, and the noise reduction effect of the two methods was compared and analyzed. Then the simulated concentrations, observed concentrations and noise-reduced observed concentrations with the best noise reduction effect were then applied to identify simulation model parameters and GCSs information, respectively, after which the corresponding identification results were compared and analyzed. The results showed that CEEMD could reduce the noise contained in the observed concentrations more effectively and make it closer to the actual values when compared with the wavelet analysis method. The accuracy of identification results based on the noise-reduced observed concentrations by was improved. As the noise contained in the observed concentrations increased, the noise reduction effect of the CEEMD decreased. Nevertheless, the accuracy of the identification results based on the noise-reduced observed concentrations was still higher than that of those based on the observed concentrations with the same intensity noise without denoising.

Selection of green remediation alternatives for chemical industrial sites: An integrated life cycle assessment and fuzzy synthetic evaluation approach

The concept of green site remediation calls for a model that can consider environmental impacts in the selection of site remediation alternatives. In this study, an integrated life cycle assessment (LCA)-fuzzy synthetic evaluation (FSE) model is developed to help practitioners select the optimal site remediation plan by incorporating life cycle impacts into the comprehensive suitability evaluation. The LCA module quantifies environmental and economic impacts using ReCiPe and Input-Output LCA methods, respectively. The impacts are evaluated along with other suitability considerations, presented in 32 indicators under ten criteria, by practitioners through a questionnaire survey. FSE is used to process the collected subjective judgments and generate a suitability index for informed selection. The integrated model is applied to a case study of an abandoned chemical industrial site contaminated by various organic chemicals and mercury. Four remediation alternatives, designed as the combined uses of ex-situ thermal desorption, in-situ thermal desorption, and in-situ containment, are evaluated. The LCA results show that the alternative with extensive use (treating 93.8 % of the contaminated soil) of in-situ thermal desorption is associated with the highest environmental and economic impacts, followed by the alternative with less extensive use (6.2 %) of in-situ thermal desorption. The FSE results show that the economic, technical, and environmental impact considerations are the top three important criteria. The integrated LCA-FSE results indicate that the alternative with mixed use of ex-situ thermal desorption and in-situ containment could be the optimal plan. Excluding LCA results could alter the suitability ranks of the alternatives.

Radon Level and Effects in Public and Residential Places in Nigeria

Reports from the World Health Organization (WHO) regarding radon as human lung carcinogen has generated a lot of research interest on the impacts of radon exposure to people all over the world. Radon concentration of different building types such as glass house, bricks and basement house structures at different locations geographically were reviewed to evaluate sustainable radon level as a strategic pathway for environmental sustainability in Nigeria. Volumes of expertises in research domain and their respective views were crystallized to forge status of Nigerians on the risk scale. Average mean radon concentration from cumulative survey suggested that dwelling and residential houses are within the recommended limit suggested by standard international and local organizations with little variations owing to several contributory factors. Research also shows that some buildings materials containing relative parent radionuclides of radon and its progenies can also contribute to indoor radon concentration, nevertheless, soil gas containing radon found in soils overlying basement rocks constitute the main source for indoor radon concentration within dwelling places. It is wholly to write that the delineated radon map will serve as a useful tool for determination of new building sites in Nigeria and as a guide for future radon remediation and monitory plan for the safest life in our dear Nation Nigeria.

A sequential decision-making framework with uncertainty quantification for groundwater management

Groundwater contamination causes significant groundwater supply risks that severely affect humans and livestock, especially in the era of climate change. Consequently, the need to develop and optimize remediation strategies such as pump and treat is indispensable. An effective and efficient strategy can reduce the spread of contaminants and cost of clean-up. However, developing such a strategy is challenging due to the inherent uncertainty and sequential nature of the problem. For example, taking actions such as drilling wells is interwoven with information gathering over time. In this paper, we formulate the groundwater remediation planning and decision problem as a partially observable Markov decision process (POMDP). A POMDP formulation allows planning by optimizing the trade-off between information gathering and the performance of possible future scenarios. We use a state-of-the-art POMDP solver called DESPOT for planning remediation strategies. The results show that DESPOT can yield much better remediation strategies than hand crafted heuristics and optimization methods. The superior performance of DESPOT is due to the incorporation of both previous information and future reward into the current decision. We also demonstrate the robustness of the POMDP formulation to measurement error.