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This systematic review addresses soil contamination by crude oil, a pressing global environmental issue, by exploring effective treatment strategies for sites co-contaminated with heavy metals and polycyclic aromatic hydrocarbons (PAHs). Our study aims to answer pivotal research questions: (1) What are the interaction mechanisms between heavy metals and PAHs in contaminated soils, and how do these affect the efficacy of different remediation methods? (2) What are the challenges and limitations of combined remediation techniques for co-contaminated soils compared to single-treatment methods in terms of efficiency, stability, and specificity? (3) How do various factors influence the effectiveness of biological, chemical, and physical remediation methods, both individually and combined, in co-contaminated soils, and what role do specific agents play in the degradation, immobilization, or removal of heavy metals and PAHs under diverse environmental conditions? (4) Do AI-powered search tools offer a superior alternative to conventional search methodologies for executing an exhaustive systematic review? Utilizing big-data analytics and AI tools such as Litmaps.co, ResearchRabbit, and MAXQDA, this study conducts a thorough analysis of remediation techniques for soils co-contaminated with heavy metals and PAHs. It emphasizes the significance of cation-π interactions and soil composition in dictating the solubility and behavior of these pollutants. The study pays particular attention to the interplay between heavy metals and PAH solubility, as well as the impact of soil properties like clay type and organic matter on heavy metal adsorption, which results in nonlinear sorption patterns. The research identifies a growing trend towards employing combined remediation techniques, especially biological strategies like biostimulation-bioaugmentation, noting their effectiveness in laboratory settings, albeit with potentially higher costs in field applications. Plants such as Medicago sativa L. and Solanum nigrum L. are highlighted for their effectiveness in phytoremediation, working synergistically with beneficial microbes to decompose contaminants. Furthermore, the study illustrates that the incorporation of biochar and surfactants, along with chelating agents like EDTA, can significantly enhance treatment efficiency. However, the research acknowledges that varying environmental conditions necessitate site-specific adaptations in remediation strategies. Life Cycle Assessment (LCA) findings indicate that while high-energy methods like Steam Enhanced Extraction and Thermal Resistivity - ERH are effective, they also entail substantial environmental and financial costs. Conversely, Natural Attenuation, despite being a low-impact and cost-effective option, may require prolonged monitoring. The study advocates for an integrative approach to soil remediation, one that harmoniously balances environmental sustainability, cost-effectiveness, and the specific requirements of contaminated sites. It underscores the necessity of a holistic strategy that combines various remediation methods, tailored to meet both regulatory compliance and the long-term sustainability of decontamination efforts.
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Restauración y Remediación Ambiental , Metales Pesados , Hidrocarburos Policíclicos Aromáticos , Contaminantes del Suelo , Hidrocarburos Policíclicos Aromáticos/análisis , Contaminantes del Suelo/metabolismo , Metales Pesados/análisis , Biodegradación Ambiental , Suelo/química , Inteligencia ArtificialRESUMEN
The aim of this study was to analyze various sustainability strategies for phosphate and phosphorous fertilizer production systems from the perspective of their holistic impacts on water, energy, and CO2 emissions. The study was conducted using the Water-Energy-Food (WEF) Nexus Tool 2.0, adapted to include the phosphate industry (WEF-P tool). It assesses the scenarios based on priorities identified by the Moroccan phosphate industry, such as the environmental impact of transporting phosphate rock by train and phosphate slurry by pipeline and increased desalinated water use. Results show that each scenario's sustainability can be assessed in terms of phosphate production, processes, resource (water and energy) availability, and CO2 emissions in mining and manufacturing areas. The analytical methodology of the tool is based on an integrated supply chain and life cycle assessment, which includes the production flows linking mining phosphate and manufacturing phosphorous fertilizers and their water and energy supply systems. Field surveys were used to identify the supply chain and estimate the relationships between production and resource consumption in each process. The tool is a decision-support platform that produces sustainability indices for multiple scenarios of resource allocation (water and energy) and CO2 emissions, allowing stakeholders to compare potential outcomes and formulate decisions based on their understanding of the actual trade-offs involved.
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Fertilizantes , Abastecimiento de Agua , Agua , Abastecimiento de Alimentos , Marruecos , Dióxido de Carbono , Fósforo , FosfatosRESUMEN
Food security and water sustainability in arid and semiarid regions are threatened by rapid population growth, declining natural resources, and global climate change. Countries in the arid regions compensate meat import by raising domestic livestock with cultivated green fodder, which diminishes lands for other crops and depletes precious water resources. This study presents for the first time an in-depth integrated food water ecosystem (FWEco) nexus modeling on the feasibility of restoring 10% of Kuwait's desert as grazing rangeland to alleviate water consumption from fodder production. Our results showed that revegetating 10% of the country's land with native species could support up to 23% of domestic livestock through natural grazing at optimal coverage (70%) and high productivity, and decrease water consumption by up to 90%. However, depending solely on natural rainfall is unlikely to achieve the optimal coverage. Strategic supplemental irrigation in the fall season (e.g., October and November) is required to maximize vegetation coverage and enhance food security and water sustainability. Significantly, strategic irrigation results in much lower net water consumption because irrigating native species requires much less water than green fodder cultivation. Therefore, revegetating desert lands with native species to restore their natural grazing service can be a sustainable approach to simultaneously improve food security and water sustainability in arid landscapes.
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Conservación de los Recursos Naturales , Ecosistema , Productos Agrícolas , Clima Desértico , Seguridad Alimentaria , AguaRESUMEN
Moving resource management and allocation away from sectoral silos to a paradigm founded in integration and leveraging cross-sectoral and trans-disciplinary synergies will result in expanded opportunities for economic development and improved social well-being (Mohtar, 2017; Mohtar and Daher, 2017). Interventions to address complex resource challenges must identify opportunities while cognizant of holistic, system level trade-offs (Daher and Mohtar, 2015; Daher et al., 2018a, b, c). These interventions must be contextualized locally: Texas has spatially varied water scarcity, energy resource abundance, and rapid population growth; in the northeastern United States water quality, drainage, and extreme weather events pose far greater challenges. While the overall system-of-systems quantification of water, energy, food and other interconnected systems remains similar across hotspots, the solutions to the challenges posed within each hotspot are bound by local knowledge, physical resource constraints, and governance challenges. This paper introduces the experience of the Texas A&M University Water-Energy-Food Nexus Initiative (WEFNI) in creating a University wide, three-year investigatory experience in which an interdisciplinary group addressed the resource challenges facing the San Antonio region. This Science of the Total Environment (STOTEN) Special Issue documents, in 9 distinct, yet complementary, research articles, the multiple dimensions of this resource hotspot. This paper reflects on the process of creating interdisciplinary teams and presents an overview of the questions and research conducted under thematic foci: data and modeling, trade-off analysis, water for food, water for energy, and governance. Lessons learned from the interdisciplinary experience are presented; potentially transferrable to addressing other resource hotspots within the US, and globally.
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Conservación de los Recursos Energéticos/métodos , Conservación de los Recursos Hídricos/métodos , Abastecimiento de Alimentos , Investigación Interdisciplinaria , TexasRESUMEN
The San Antonio Region is home to a rapidly growing population with developing energy and agricultural sectors competing for water, land, and financial resources. Despite the tight interconnectedness between water, energy, and food challenges, little is known about the levels of communication and coordination among the various officials responsible for making the decisions that affect the management and planning of the three resource systems. It has been postulated that efficient communication is a prerequisite to developing resource allocation strategies that avoid potential unintended negative consequences that could result from inefficient allocation of natural resources and competing demands. Factors that may impact communication are identified and their potential roles are considered in improving existing levels of communication between San Antonio's water officials and those at other energy, food, and water institutions in the San Antonio Region. A questionnaire designed to gather information on stakeholder concerns, frequency of communication, and participation in engagement forums was sent to public water officials in the Region. Using social network analysis and bivariate Ordinary Least Square regression analysis, the authors conclude that while modest levels of communication exist among water institutions, a very low level of communication exists between water institutions and those responsible for food and energy. It was further concluded that the frequency of communication among officials at different water institutions is higher among those that participated in stakeholder engagement activities. However, there is insufficient evidence to suggest that participation in stakeholder engagement activities improves communication frequency between water stakeholders and those in the food and energy sectors. There is also insufficient evidence to conclude that people at water institutions in San Antonio would have a higher frequency of communication with other water, energy, and food stakeholder in correlation with a higher level of concern about future water availability in the Region.
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Conservación de los Recursos Naturales/métodos , Abastecimiento de Alimentos/métodos , Abastecimiento de Agua/métodos , Agricultura , Humanos , Texas , AguaRESUMEN
Approaching water, energy, and food, as interconnected system of systems, as an alternative to traditional silo-based resources planning and management approaches continues to fall short of expectations of its research-backed benefits. The lack of nexus applications in policy and decision making can be related to numerous factors, with the main barrier being the complex nature of "nexus" systems combined with the disarray of tools attempting to model its interconnections. The paper aims to provide a method for comparing the perceived complexity of nexus tools identified by international organizations as well as primary literature sources. Eight separate criteria are introduced and discussed as measures of a tool "complexity index" and used to score the relative simplicity, or complexity, of a given tool. The result of this process is used to identify trends within existing nexus-assessment tools while guiding potential users towards appropriate tool(s) best-suited for their case study needs and objectives. The main objectives of this paper are to: 1) categorize nexus assessment tools according to a criteria-set which allows for suitable tool selection; 2) identify a method for rapid evaluation of the trade-offs for choosing different tools (simple-complex spectrum). The results of the comparative analysis of the selected nexus assessment tools concur with literature citing a growing gap between nexus research and applications in actual policy and decision-making settings. Furthermore, results suggest that tools receiving higher complexity scores, while being able to capture details to specific resource interactions, are unable to cover a larger number of interactions and system components simultaneously, as compared to lower complexity score tools. Lastly, the outcome of the analysis point towards the need for integrating more preliminary assessment capabilities, i.e. diagnostics, guidelines, and capacity building, into existing tools that improve the communication and translation of model outputs into policy and decision-making.
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Ecosistema , Monitoreo del Ambiente/métodos , Alimentos , Cadena Alimentaria , Programas Informáticos , AguaRESUMEN
The paper introduces a holistic framework that identifies the links between energy and other systems (water, land, environment, finance, etc.), and measures the impact of energy portfolios, to offer a solid foundation for the best sustainable decision making in energy planning. The paper presents a scenario-based holistic nexus tool, Energy Portfolio Assessment Tool (EPAT) that provides a platform for energy stakeholders and policymakers to create and evaluate the sustainability of various scenarios based on the water-energy-food (WEF) nexus approach. The tool is applied to a case study in Texas, USA. Scenarios considered are set by the U.S. Energy Information Administration (EIA): EIA Reference Case - 2015, EIA Clean Power Plan (CPP) & Reference Case - 2030, and EIA No-CPP & Reference Case - 2030. In the presence of the CPP, total water withdrawal is expected to decrease significantly, while total water consumption is projected to experience a slight decrease due to the increase in water consumption in electricity generation caused by the new electricity mix. The CPP is successful in decreasing emissions, but is accompanied by tradeoffs, such as increased water consumption and land use by electricity generation. The absence of the CPP will lead to an extreme surge in total water withdrawn and consumed, and in emissions. Therefore, conservation policies should move from the silo to the nexus mentality to avoid unintended consequences that result in improving one part of the nexus while worsening the other parts.
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This research investigates the relation between water, energy, and transportation systems, using the growing hydraulic fracturing activity in the Eagle Ford shale play region of southwest Texas in which the local water systems and road infrastructure were not designed for the frequent transport of water into the production site and of produced gas and oil from the site as are often required for hydraulic fracturing. The research: 1) quantifies the interconnections between water, energy, and transportation systems specific to the Eagle Ford shale region; 2) identifies and quantifies the economic, social, and environmental indicators to evaluate scenarios of oil and gas production; and 3) develops a framework for analysis of the economic, societal, and long term sustainability of the sectors and 4) an assessment tool (WET Tool) that estimates several economic indicators: oil and natural gas production, direct and indirect tax revenues, and average wages for each scenario facilitates the holistic assessment of oil and gas production scenarios and their associated trade-offs between them. Additionally, the Tool evaluates these social and environmental indices, (water demand, emissions, water tanker traffic, accidents, road deterioration, and expected average employment times). Scale of production is derived from the price of oil and gas; government revenues from production fluctuations in relation to rise and fall of the oil and gas market prices. While the economic benefits are straightforward, the social costs of shale development (water consumption, carbon emissions, and transportation/infrastructure factors), are difficult to quantify. The tool quantifies and assesses potential scenario outcomes, providing an aid to decision makers in the public and private sectors that allows increased understanding of the implications of each scenario for each sector by summarizing projected outcomes to allow evaluation of the scenarios and comparison of choices and facilitate the essential dialogue between these sectors.
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The 2017 Texas Water Development Board's State Water Plan predicts a 41% gap between water demand and existing supply by 2070. This reflects an overall projection, but the challenge will affect various regions of the state differently. Texas has 16 regional water planning zones characterized by distinct populations, water demands, and existing water supplies. Each is expected to face variations of pressures, such as increased agricultural and energy development (particularly hydraulic fracturing) and urban growth that do not necessarily follow the region's water plan. Great variability in resource distribution and competing resource demands across Texas will result in the emergence of distinct hotspots, each with unique characteristics that require multiple, localized, interventions to bridge the statewide water gap. This study explores three such hotspots: 1) water-food competition in Lubbock and the potential of producing 3â¯billionâ¯gallons of treated municipal waste water and encouraging dryland agriculture; 2) implementing Low Impact Developments (LIDs) for agriculture in the City of San Antonio, potentially adding 47â¯billionâ¯gallons of water supply, but carrying a potentially high financial cost; and 3) water-energy interrelations in the Eagle Ford Shale in light of well counts, climate dynamics, and population growth. The growing water gap is a state wide problem that requires holistic assessments that capture the impact on the tightly interconnected water, energy, and food systems. Better understanding the trade-offs associated with each 'solution' and enabling informed dialogue between stakeholders, offers a basis for formulating localized policy recommendations specific to each hotspot.
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Conservación de los Recursos Naturales/métodos , Abastecimiento de Agua/estadística & datos numéricos , Ciudades , Alimentos , Texas , AguaRESUMEN
Securing sources for water reuse and coordinating efforts of water governing agencies to do so are critical to realizing the potential of reused water to provide nearly 24% of the water demand of the San Antonio Region, defined as regions "L" and "K" by the Texas Water Development Board (TWDB). This research identifies key governance factors that contribute to increasing water reuse within the water planning sector and tests four governance-related hypotheses for their impact on efforts to increase water reuse in the Region. Variables tested include: the type and scale of water governance agency, the agency's frequency of communication with the TWDB, and the agency's familiarity with the TWDB water strategy supplies as defined in the Texas State Water Plan of 2017. A questionnaire addressing these variables was sent to water governing agencies in regions L and K; the response rate was 39.5%. Each variable was cross-tabulated with agency efforts to increase water reuse. Seven regression analysis models were calculated among the factors to test for statistical significance and impact on increasing water reuse efforts. Results indicate that nearly 70% of agencies in the regions have efforts to increase water reuse by as much as 10%. Among the tested hypotheses, frequency in communication with the TWDB was statistically significant for increasing agency efforts to reuse water. Results from these hypotheses are expected to help water managers identify key, governance-related factors that contribute to increased water reuse.
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The long-term effect of using treated wastewater is not clearly defined: some researchers argue that it is better than freshwater for the soil health; others disapprove, claiming that irrigation with unconventional water resources causes soil degradation. This study assesses the impact of irrigation with non-traditional water on the chemical and mineralogical properties of a calcareous clayey soil from West Texas. The exponential rise in population and the realities of climate change contribute to the global increase in freshwater scarcity: non-conventional water sources, such as treated wastewater (TWW) and brackish groundwater (BGW), offer potentially attractive alternative water resources for irrigated agriculture. For this research, the differences between TWW and BGW were addressed by collecting and analyzing water samples for salt and nutrient content. Soil samples from three horizons (Ap, A, and B) were obtained from three different fields: Rainfed (RF), BGW irrigated, and TWW irrigated. Soil was analyzed for texture, salinity, sodicity, and carbon content. Clay mineralogy of the three different fields was analyzed using the B-horizons. The outcomes from the analysis showed that the BGW from the Lipan aquifer has higher salinity and is harder compared to TWW. Although the exchangeable sodium percentage (ESP), sodium adsorption ratio (SAR), and electroconductivity (EC) increased marginally compared to the control soil (RF), the soils were in good health, all the values of interest (SARâ¯<â¯13, ESPâ¯<â¯15, pHâ¯<â¯8.5, and ECâ¯<â¯4) were low, indicating no sodicity or salinity problems. Smectite, illite, and kaolinite were identified in the three B-horizon samples using bulk X-ray diffraction (XRD). Overall, no major changes were observed in the soil. Thus, TWW and BGW are viable replacements for freshwater irrigation in arid and semi-arid regions.
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Soil aggregates structure (pedostructure) plays a pivotal role in regulating water and nutrient circulation, and consequently defines soil health, productivity, and water use efficiency. However, the soil aggregates structure is not currently considered in the quantification of soil-water holding properties. The authors applied a thermodynamic and soil structure-based approach to quantify soil-water holding properties. The paper provides a methodology, based on pedostructure concept, to quantify field capacity (FC), permanent wilting point (PWP), and available water (AW). The validity of the developed method was tested through application to two types of soil: a loamy fine sand soil and a silt loam soil. The calculated values for FC, PWP, and AW were compared with the FAO recommended values of FC, PWP and AW. For the loamy fine sand, the calculated values were: FC = 0.208 m3/m3, PWP = 0.068 m3/m3, and AW = 0.140 m3/m3 all of which fall within the recommended values of FAO for such a soil type. Similarly, the calculated values for the silt loam were: FC = 0.283 m3/m3, PWP = 0.184 m3/m3, and AW = 0.071 m3/m3 all were in agreement with the FAO recommended ranges for such a soil type. â¢A thermodynamic, structure-based approach for soil water holding properties.â¢Unique solutions for quantifying both field capacity and permanent wilting point.
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Wastewater reuse is a practice that has been gaining attention for the past few decades as the world's population rises and water resources become scarce. Wastewater application on soil can affect soil health, and the manner and extent to which this occurs depends heavily on soil type and water quality. This study compared the long-term (15+ years) effects and suitability of using secondary-level treated municipal wastewater and brackish groundwater for irrigation on the water holding capacity of a clayey, calcareous soil on a cotton farm near San Angelo, Texas. The soil-water holding properties were determined from the extracted hydrostructural parameters of the two characteristic curves: water retention curve and soil shrinkage curve based on the pedostructure concept. In the pedostructure concept, these hydrostructural parameters are characteristic properties of the soil aggregates structure and its thermodynamic interactions with water. Results indicate that use of secondary treated wastewater increased available water capacity in the top horizon (0-15â¯cm) and decreased the available water holding capacity of this particular soil in the sub-horizons (15-72â¯cm). The brackish groundwater irrigation resulted in no effect on available water capacity in the top horizon, but significantly decreased it in the sub-horizons as well. The rainfed soil was the healthiest soil in terms of water holding capacity, but rainfall conditions do not produce profitable cotton yields. Whereas, treated wastewater irrigated soil is producing the highest yields for the farmer. Thus, this treated wastewater source and irrigation system can serve as a suitable irrigation alternative to using brackish groundwater, enhancing the water resource sustainability of this region.
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Field data from five air sparging sites were used to assess the effect of several soil, contaminant, and air sparging system factors on the removal time and associated costs required to reach specified clean-up criteria. Numerical simulations were also performed to better assess the field data and to expand the data sets beyond the five field sites. Ten factors were selected and evaluated individually over a range of values based on information from practitioners and the literature. Trends in removal time and removal cost to reach a specified clean-up criterion were analyzed to ascertain the conditions controlling contaminant removal with variations in each factors' value. A linear sensitivity equation was used to quantify system dynamics controlling the observed contaminant removal trends for each factor. Factors found most critical across all field sites in terms of removal time and/or cost were contaminant type, sparge pulsing schedule, number of wells, maximum biodecay rate, total soil porosity, and aquifer organic carbon content. Factors showing moderate to low effect included the depth of the sparge point below the water table, air injection rate/pressure, horizontal air conductivity, and anisotropy ratio. At each field site, subsurface coverage of sparged air, sparged air residence time, contaminant equilibrium in the system, contaminant phase distribution, oxygen availability to microbes, and contaminant volatility seem to control the system responses and were affected by one or more of the 10 factors evaluated.