Long-term Management Plan Research Articles

A Mathematical Model for Localized Corrosion of Copper Under a Droplet

The Nuclear Waste Management Organization (NWMO) is responsible for the implementation of Adaptive Phased Management (APM), the federally-approved plan for the safe long-term management of Canada’s used nuclear fuel.1 Under the APM plan, used nuclear fuel will ultimately be placed within a deep geological repository in a suitable host rock formation. Part of evaluating the long-term performance and safety of the repository system is understanding the behavior of the copper coated container with respect to localized corrosion. The Canadian Deep Geological Repository (DGR) system does not lend itself to passivation of the copper surface, owing to the nature of copper and the environment, so conventional pitting corrosion is not expected. However, the system will transition from dry to wet conditions, and there is a possibility that deliquescent species may be present on the container surface, which may produce different localized environments, and as a result, localized corrosion damage.A 2-D axisymmetric time-dependent model for localized corrosion is being developed using the concept of an Evans droplet,2 in which the metal is covered by a drop of electrolyte. The model considers the aerobic, unsaturated conditions likely to be found at early times in a deep geological repository.3 In the present work, sodium chloride was chosen as the supporting electrolyte and the concentration of oxygen in the solution at the droplet boundary was assumed to be in equilibrium with the oxygen in the surrounding air. The electrochemical reactions proposed for the copper metal surface include oxygen (O2) reduction and copper dissolution through a sequence of steps in which copper chloride is an adsorbed intermediate that reacts in a second chemical step to form cuprous chloride (CuCl2 -). The model accounts for the homogeneous oxidation of cuprous chloride to form cupric ion (Cu2+), and Cu2+ introduced a cathodic reaction to form CuCl2 -. Hydrolysis of both Cu(I) and Cu(II) to form precipitates is also considered in the current model.The mathematical model is developed using the finite-element method (COMSOL Multiphysics). The mathematical approach is similar to that developed by Chang et al.4 for corrosion of iron under a droplet or under a deposit. The model includes coupled, nonlinear, diffusion equations for ionic species, which include the contribution of migration, local electroneutrality, homogeneous reactions, and formation of precipitates. One of the unique approaches taken in this work is that the anodic and cathodic regions are not predefined but are rather determined by values of local concentration and potential from the simulation results. While in its preliminary stages, the model shows a time-dependent radial distribution of anodic and cathodic current, fractional coverage of the CuCl adsorbed intermediate, and dissolved oxygen concentration.References NWMO, “Choosing a Way Forward. The Future Management of Canada’s Used Nuclear Fuel. Final Study,” Nuclear Waste Management Organization, Toronto, Ontario, 2005.U. R. Evans, The Corrosion of Metals, E. Arnold & Company, London, 1926.F. King, M. Kolar, P. Maak, “Reactive-transport model for the prediction of the uniform corrosion behavior of copper used fuel containers,” Journal of Nuclear Materials 379 (2008) 133-141.Y.-C. Chang, R. Woollam, and M. E. Orazem, "Mathematical Models for Under-Deposit Corrosion: 1. Aerated Media,'' Journal of The Electrochemical Society, 161 (2014), C321-C329. AcknowledgementThis work was supported by the Nuclear Waste Management Organization, Canada, under project 2000904.

Plant extract mediated ZnO-NPs as photocatalyst for dye degradation: An overview

Clean water is the basic need of all, it is impossible to imagine a future without it. However, the lack of a long-term water management plan and rapid industrialization resulted in the contamination of water sources to a dangerous extent. Excessive use of toxic textile dyes and their secretion in natural water resources is one of the major concerns for today's world. Photocatalysis is one of the best phenomena to resolve the issue of harmful textile dyes in the aquatic environment, where the photo-induced electron and hole pairs generated by excitation of electrons from the valence band to the conduction band by light irradiance can be used for the degradation of dye molecules through redox reactions. ZnO is a semiconductor material that shows excellent potential in photocatalysis. As the synthesis of biocompatible ZnO nanoparticles (NPs) using plant extract as biological reducing and capping agents is one of the best ways to have all the benefits of different physicochemical properties of nanomaterials without potential environmental and human health risks resulted from nanoparticles. Therefore, the use of green synthesized ZnO-NPs prepared using various parts of the plant in the degradation of harmful textile dyes has been explored by many researchers. In this article, we will provide an overview of the procedure to synthesize the biocompatible ZnO-NPs and their use in the photocatalytic degradation of dyes.

Safety and Health in Mining

In the history of the mining sector, in its beginnings it faced very high levels of risks both safety and health. The data are limited to serious accidents, and these are mainly associated with falls from land, transport and machinery. Analysis of these data suggests that the leading causes of death tend to be the same as those of serious injuries, while disasters have a different profile. Over the past decade, mining disasters have been associated with explosions due to flammable gases, a fire on a conveyor belt, a flood of mud and water, and rock outbursts. Mandatory compliance with a company's safety, health and environmental regulations is a minimum and can be significantly improved by adding a long-term management planning and implementation process with a deeper cultural shift towards continuous improvement in safety and quality. Note that the purpose of integrating health and safety into other management systems is the need for health and safety management to be central, rather than an organizational objective.

Accelerating the development of structural complexity: lidar analysis supports restoration as a tool in coastal Pacific Northwest forests

A century of land-use changes and intensive plantation-style forestry in the Pacific Northwest have resulted in a substantial deficit of structurally complex late-successional forests, which serve key ecological and social functions. Restoration treatments can theoretically accelerate the development of structural complexity in simplified forest stands, but our understanding of the short-term effects of such treatments on forest structure and gap patterns is still emerging. In this study, we used a bi-temporal airborne lidar dataset to assess short-term (10 years post-treatment) effects of restoration treatments on the structural complexity of forest stands in the Ellsworth Creek Preserve in southwestern Washington. We also compared forest structure and gap patterns between treated stands and existing late-successional areas within the preserve. Restoration treatments in older stands (60- to 80-years old) resulted in a greater increase in the mean and variability of both vertical and horizontal structural complexity and a considerable increase in the density of canopy gaps, indicating accelerated development towards increased structural complexity. Treatments in the younger stands (20- to 30-years old) primarily accelerated the development of vertical canopy complexity. Older treated stands within the preserve will require natural growth in canopy height, increased regeneration density, and filling in and diversification of canopy gaps to reach the structural complexity of late-successional forests in the preserve, but accelerating these developments may require additional restoration-focused treatments. Forest managers in the region should consider restoration treatments as a viable option for improving short-term structural complexity in simplified forest stands. We also encourage long-term management and monitoring plans that continue to address the deficit of late-successional forests in the region.

Strategic decision support for long-term conservation management planning

Forward thinking conservation-planning can benefit from modeling future landscapes that result from multiple alternative management scenarios. However, long-term landscape modeling and downstream analyses of modeling results can lead to massive amounts of data that are difficult to assemble, analyze, and to report findings in a way that is easily accessible to decision makers. In this study, we developed a decision support process to evaluate modeled forest conditions resulting from five management scenarios, across 100 years in California’s Lake Tahoe basin; to this end we drew upon a large and complex hierarchical dataset intended to evaluate landscape resilience. Trajectories of landscape characteristics used to inform an analysis of landscape resilience were modeled with the spatially explicit LANDIS-II vegetation simulator. Downstream modeling outputs of additional landscape characteristics were derived from the LANDIS-II outputs (e.g., wildlife conditions, water quality, effects of fire). The later modeling processes resulted in the generation of massive data sets with high dimensionality of landscape characteristics at both high spatial and temporal resolution. Ultimately, our analysis distilled hundreds of data inputs into performance trajectories for the five modeled management scenarios over a 100-year time horizon. We then evaluated each management scenario based on inter-year variability, and absolute and relative performance. We found that management scenarios with a greater emphasis on proactive biomass reduction outperformed management approaches with minimal biomass reduction. These results, and the process that led to them, provided decision makers with insight into forest dynamics based on a rational, transparent, and repeatable decision support processes.

Killing them softly: a review on snake translocation and an Australian case study

Human-wildlife conflicts with ‘nuisance’ snakes are becoming more frequent around the world as urbanisation continues to encroach on remaining habitats. In an attempt to mitigate this issue, snakes are often translocated in an uncontrolled fashion, with little to no conservation value. To determine the most appropriate methods of translocation we reviewed the available primary literature on studies performing translocations of snakes. We found two types of translocation: long and short-distance. Based on the welfare of the animals involved and difficulty of achieving success with long-distance translocations, we deduced that short-distance translocations are the most favourable. We also reviewed the literature on a third method - repatriating wild populations of snakes with captive-bred or captive-reared individuals, the results of which were very similar to those of long-distance translocations. In conjunction with a mark recapture study carried out by snake catchers in Darwin, Australia, we use our findings to make suggestions on the most appropriate course of action for the mitigation-based snake catching activities in Australia. The difficulty of ensuring successful outcomes for long distance translocations along with a high mortality rate meant we cannot suggest this as an appropriate method for managing ‘nuisance’ snakes. Instead, we argue that short distance translocations are the most suitable for the welfare of the snakes involved. Nevertheless, no outcome will be more favourable for the snakes than to be simply released within their home range accompanied by a change in attitude of the general public towards a willingness to coexist. Although we focus primarily on Australia our suggested framework can be applied in any country where there is conflict with snakes. Furthermore, should our suggestions be implemented, they are merely a temporary solution to an ongoing problem and we are in desperate need for further research to devise a long-term management plan.

Care for survivors of acute kidney injury.

The effects of acute kidney injury (AKI) extend beyond the acute illness phase. Patients who survive AKI are at increased risk of hospital readmission, chronic disease including kidney and cardiovascular disease, frailty and death. AKI may be overlooked among more obvious or complex healthcare concerns. While developing a cogent, systemic response to care after AKI is a neglected public health priority, attention to several common challenges may improve patient outcomes. The aim of this article is to highlight common challenges in managing survivors of AKI and offer suggestions toguide management. For clinicians managing survivors of AKI, identifying and communicating patient priorities, risk factors and comorbidities including a history of AKI is important. Concurrent management challenges include education regarding lifestyle and pharmacotherapy, managing medication interruptions and dose adjustments, and re-establishing a long-term management plan for chronic diseases.

Molecular Taxonomy and Diversification of Atlantic Skates (Chondrichthyes, Rajiformes): Adding More Pieces to the Puzzle of Their Evolutionary History.

Conservation and long-term management plans of marine species need to be based upon the universally recognized key-feature of species identity. This important assignment is particularly challenging in skates (Rajiformes) in which the phenotypic similarity between some taxa and the individual variability in others, hampers accurate species identification. Here, 432 individual skate samples collected from four major ocean areas of the Atlantic were barcoded and taxonomically analysed. A BOLD project ELASMO ATL was implemented with the aim of establishing a new fully available and well curated barcode library containing both biological and molecular information. The evolutionary histories of the 38 skate taxa were estimated with two concatenated mitochondrial markers (COI and NADH2) through Maximum Likelihood and Bayesian inference. New evolutionary lineages within the genus Raja were discovered off Angola, where paleogeographic history coupled with oceanographic discontinuities could have contributed to the establishment of isolated refugia, playing a fundamental role among skates’ speciation events. These data successfully resolved many taxonomic ambiguities, identified cryptic diversity within valid species and demonstrated a highly cohesive monophyletic clustering among the order, laying the background for further inference of evolutionary patterns suitable for addressing management and conservation issues.

Long-term water use characteristics and patterns of typical tree species in seasonal drought regions

In the areas with seasonal drought, water is the key factor affecting plant growth and development. Based on long-term continuous observation data, it is of great significance to explore plant water use patterns for vegetation construction in areas with seasonal drought. Taking Platycladus orientalis in Beijing mountainous area as the research object, stable hydrogen and oxygen isotope technique was applied to measure the isotopic composition of water from the soil, plant branches, and precipitation from 2012 to 2017. The relative contribution of soil water from different soil layers to P. orientalis was quantified by the MixSIAR model. The results showed that soil water in the deep layer (40-100 cm) was more stable than that in the shallow layer (0-40 cm). The variation of soil water content and water isotope values in the shallow layer were more obvious due to the effects of evaporation and precipitation. P. orientalis mainly absorbed stable deep soil water, with a relative contribution rate of 55.7%. In the dry season, with the decreases of soil water content, the absorption depth of plants to soil water gradually shifted to the shallow layer. Under conditions of moist, natural condition, mild drought and moderate drought, the relative contribution rates of deep soil water were 59.8%, 57.9%, 54.6%, 52.7%, respectively. To maintain higher transpiration in the wet season, P. orientalis relied more on deep soil water under mild and moderate drought conditions than in the dry season. Under the conditions of moist, natural condition, mild drought and moderate drought, the relative contribution rates of deep soil water were 58.9%, 57.6%, 56.4%, and 57.1%, respectively. The adaptive characteristic of P. orientalis, which adjusts the depth of root water absorption according to soil moisture condition, is of great significance for tree species selection in ecological afforestation and long-term management planning in areas with seasonal drought.

EXPERIENCE OF LONG-TERM USE OF DIENOGEST FOR THE TREATMENT OF ADENOMYOSIS

Endometriosis refers to a chronic, often recurrent disease that requires the appointment of a long-term management plan and the patient with the appointment of therapy that effectively affects the clinic of this disease, at the same time having good tolerability, ensuring the patient's adherence to this method of treatment. This dictates the need for careful selection of a drug that meets such requirements. Moreover, studies of drug therapy for endometriosis should also be prolonged. In this case, they allow you to qualitatively assess the effectiveness of a particular type of treatment in the context of routine clinical practice. The main clinical manifestations of endometriosis of the uterine body-adenomyosis are pain syndrome, manifested by various types of pain (dysmenorrhea, dyspareunia, dyschesia, chronic pelvic pain) and the presence of abundant uterine bleeding. The presented clinical case demonstrates the effectiveness of long-term (for 36 months) use of dienogest at a dosage of 2 mg per day (the drug Vizanna) in a continuous mode in the treatment of a patient with adenomyosis. By the 4th month of therapy, the pain syndrome, manifested by dysmenorrhea and dyspareunia, which is the leading clinical manifestation of this pathology in the patient, was completely stopped. The proposed type of therapy has also demonstrated its effectiveness in relation to another clinical manifestation of the disease - heavy uterine bleeding. By the 6th month of therapy, the patient had developed persistent amenorrhea. Good tolerability and the absence of side effects, along with a pronounced clinical effect, led to a high adherence of the patient to this type of drug therapy and allowed her to continue it in the future with dynamic monitoring.

The issues of international legal protection of the Lake Baikal: results of the 44th session of the World Heritage Committee

The subject of this research is the decisions made at the 44th session of the World Heritage Committee in the matter of conservation of the World Heritage Site – Lake Baikal. Using the scientific methods of analysis, synthesis, etc., the author carries out in-depth analysis of the content of documents approved at the 44th session of the World Heritage Committee regarding the Lake Baikal held in July 2021, within the framework of which the international community estimates the discharge of obligations by the Russian Federation concerning the preservation of ecosystem of the Lake Baikal. The goal of this article is to explore and offer solutions to certain problematic aspects of international legal protection of the Lake Baikal in the context of discussion unfolded at the 44th session of the World Heritage Committee. The article examines the legislative changes in regulation of the various groups of social relations in the Central Ecological Zone of Lake Baikal and its islands, and formulates recommendations for their improvement. The author determines the non-systemic nature of legal regulation in this sphere, and this, inability to forecast changes in the regime of legal protection of the Lake Baikal. For solution of the indicated issue, the author formulates the proposal on the need to develop and approve the long-term management plan for the World Heritage Site “Lake Baikal” using approaches of the bodies of the system of world heritage protection. The development of such plan would be facilitated by extension of the umbrella regime of the listed territory to the Central Ecological Zone of Lake Baikal and its islands, as well as by creation of single administration that would also control other listed territories that are part of it. Analysis is conducted on the topical issues related to conservation of the Lake Baikal ecosystem, which were outlined at the 44th session of the World Heritage Committee. The author suggests a number of amendments to the federal legislation aimed at strengthening the national legal protection of World Heritage Sites.

Mixed Regional Shifts in Conifer Productivity under 21st-Century Climate Projections in Canada’s Northeastern Boreal Forest

Models of forest growth and yield (G&Y) are a key component in long-term strategic forest management plans. Models leveraging the industry-standard “empirical” approach to G&Y are frequently underpinned by an assumption of historical consistency in climatic growing conditions. This assumption is problematic as forest managers look to obtain reliable growth predictions under the changing climate of the 21st century. Consequently, there is a pressing need for G&Y modelling approaches that can be more robustly applied under the influence of climate change. In this study we utilized an established forest gap model (JABOWA-3) to simulate G&Y between 2020 and 2100 under Representative Concentration Pathways (RCP) 2.6, 4.5, and 8.5 in the Canadian province of Newfoundland and Labrador (NL). Simulations were completed using the province’s permanent sample plot data and surface-fitted climatic datasets. Through model validation, we found simulated basal area (BA) aligned with observed BA for the major conifer species components of NL’s forests, including black spruce [Picea mariana (Mill.) Britton et al.] and balsam fir [Abies balsamea (L.) Mill]. Model validation was not as robust for the less abundant species components of NL (e.g., Acer rubrum L. 1753, Populus tremuloides Michx., and Picea glauca (Moench) Voss). Our simulations generally indicate that projected climatic changes may modestly increase black spruce and balsam fir productivity in the more northerly growing environments within NL. In contrast, we found productivity of these same species to only be maintained, and in some instances even decline, toward NL’s southerly extents. These generalizations are moderated by species, RCP, and geographic parameters. Growth modifiers were also prepared to render empirical G&Y projections more robust for use under periods of climate change.

Monitoring ambient air quality in Indian city airsheds

An understanding of sources contributing to a city’s air pollution problem is crucial for building an effective clean air action plan. All the non-attainment cities under the National Clean Air Programme (NCAP) are planning or conducting a source apportionment study. Irrespective of the approaches and equipment selected to conduct these studies, the initiation process requires an understanding of the pollution loads, mix of sources, and geography of the city to decide how much to monitor for better spatial representation and how many times to monitor for better temporal representation. In this report, we defined (a) The size of NCAP city airsheds (b) The recommended number of ambient air quality monitoring sites in an airshed (c) The operational sampling frequency to support receptor-based source apportionment studies. These resources are necessary for strengthening the monitoring needs of an airshed to track pollution levels, to conduct receptor-model-based source apportionment studies, and to support long-term air quality management plans. Together, 122 NCAP cities were clubbed into 94 airsheds representing a total of 154 cities and a total population of 290.6 million - 66 airsheds contain only one city; 16 airsheds contain two cities, nine airsheds contain three cities and four airsheds (Chandigarh, Delhi, Mumbai, and Kolkata) contain 11, 7, 7, and 4 cities respectively. For the 94 airsheds, a total of 1700 sampling sites are recommended to measure and analyse particulate matter, at an average of 18 per airshed. The Tier-1 cities on the NCAP list - Ahmedabad, Bengaluru, Delhi, Hyderabad, Kolkata, Mumbai, and Pune require at least 33, 41, 78, 36, 70, 68, and 32 sampling sites, respectively, which is more than the current operational monitoring capacity in the cities.

Development of the Asia Pacific Consortium on Osteoporosis (APCO) Framework: clinical standards of care for the screening, diagnosis, and management of osteoporosis in the Asia-Pacific region

SummaryGuidelines for doctors managing osteoporosis in the Asia-Pacific region vary widely. We compared 18 guidelines for similarities and differences in five key areas. We then used a structured consensus process to develop clinical standards of care for the diagnosis and management of osteoporosis and for improving the quality of care.PurposeMinimum clinical standards for assessment and management of osteoporosis are needed in the Asia-Pacific (AP) region to inform clinical practice guidelines (CPGs) and to improve osteoporosis care. We present the framework of these clinical standards and describe its development.MethodsWe conducted a structured comparative analysis of existing CPGs in the AP region using a “5IQ” model (identification, investigation, information, intervention, integration, and quality). One-hundred data elements were extracted from each guideline. We then employed a four-round Delphi consensus process to structure the framework, identify key components of guidance, and develop clinical care standards.ResultsEighteen guidelines were included. The 5IQ analysis demonstrated marked heterogeneity, notably in guidance on risk factors, the use of biochemical markers, self-care information for patients, indications for osteoporosis treatment, use of fracture risk assessment tools, and protocols for monitoring treatment. There was minimal guidance on long-term management plans or on strategies and systems for clinical quality improvement. Twenty-nine APCO members participated in the Delphi process, resulting in consensus on 16 clinical standards, with levels of attainment defined for those on identification and investigation of fragility fractures, vertebral fracture assessment, and inclusion of quality metrics in guidelines.ConclusionThe 5IQ analysis confirmed previous anecdotal observations of marked heterogeneity of osteoporosis clinical guidelines in the AP region. The Framework provides practical, clear, and feasible recommendations for osteoporosis care and can be adapted for use in other such vastly diverse regions. Implementation of the standards is expected to significantly lessen the global burden of osteoporosis.

Rewilding the world’s large carnivores without neglecting the human dimension

Rewilding is a growing conservation concept that seeks to enhance biodiversity and improve ecosystem functioning. When rewilding includes the reintroduction of large carnivores to landscapes from which they have been extirpated, assessing the societal impacts and acceptability is as, if not more, important than assessing the ecological feasibility (in: Smith et al, Application to Natural England for the trial reintroduction of lynx to England, Lynx UK Trust, Kielder, 2015a, Application for the trial reintroduction of lynx to Scotland, Lynx UK Trust, Kielder, 2015b; Johnson and Greenwood 2020). We caution that not including the human dimension when modelling the feasibility of a particular conservation action will produce flawed results by masking potentially low public acceptance and conflicts with particular stakeholders. Furthermore, repeated failure to work within a socio-ecological system (SES) framework threatens to alienate key stakeholders, particularly when NGOs propose trial reintroductions prior to any rigorous consideration of the human dimension. When the interests of one party (e.g. NGOs or conservationists) are perceived to be asserted over the interests of others (e.g. small-livestock farmers), the stage is set for a conservation conflict. Conservation conflicts not only hamper worthwhile conservation initiatives but drive a wedge between key stakeholders that need to agree on a clear long-term conservation and management plan before the state will accede to such proposals.

Hydrochemical dynamics of water quality for irrigation use and introducing a new water quality index incorporating multivariate statistics

Anthropogenic contamination, including the adaptation of sophisticated agricultural methodologies, has rendered a steep decline in the water and soil quality across the globe. This, in turn, has adversely affected the crop productivity. Hence, to utilize water from a source, a review assessment regarding the water suitability is essential. The present study proposes a new irrigation-based water quality index (IWQI), integrating statistics; hierarchical cluster analysis (HCA) and principal component analysis (PCA), to specific water use. Twenty-three sampling locations were chosen for analyses of 13 water quality parameters from October 2017 to February 2019 from Deepor Beel, Assam, to determine the efficacy of the proposed water quality index. HCA divided the 23 locations into 3 clusters, after which, PCA for each independent cluster provided component scores. These component scores were then used to estimate weights for each parameter for all the 23 locations. The IWQI categorized all the sampling locations as “Very Good”, thereby rendering them fit for irrigation. This was validated through the use of various irrigation parameters, such as sodium adsorption ratio (SAR), Kelly’s ratio (KR), soluble sodium percentage (SSP), residual sodium carbonate (RSC), permeability index (PI), and magnesium adsorption ratio (MgR). USSL and Wilcox plots were also considered for the correlation. IWQI was observed to provide an excellent association with all the parameters. Thus, the study would prove fruitful in establishing long-term and extensive management plans to the conservation of natural water resources.

Shift of nitrate sources in groundwater due to intensive livestock farming on Jeju Island, South Korea: With emphasis on legacy effects on water management

Time lags between anthropogenic nitrogen inputs and their impacts to nitrate levels cause a misunderstanding for sources and subsequently misguide the groundwater management.We investigated the hydrochemical data of groundwater samples (n = 172 from 49 wells) with chlorofluorocarbons (CFCs)-based groundwater age dating and stable N (δ15N) and O isotopes (δ18O) of nitrate to assess the legacy effect of livestock farming to groundwater in an agricultural area where intensive livestock farming started in the 1970s and illegal dumping of manure wastewater in a lava cave was revealed in 2015. Approximately 90% of the groundwater samples had nitrate concentrations exceeding the natural threshold (5.5 mg/L NO3−) for nitrate contamination and 34% exceeded the World Health Organization's guideline for drinking water quality (44.3 mg/L), indicating severe nitrate contamination. The δ15NNO3 values (5.5 to 24.3‰) in groundwater exceeding the threshold of nitrate showed that livestock manure was a major nitrate source, while ammonium fertilizer also seemed influential given the δ15NNO3 values in the overlapping fields of N sources. Factor analysis of hydrochemical data also supported nitrate contamination by manure as well as by plant farming in the study area. Based on the spatial distribution of nitrate levels and δ15NNO3, livestock farming affected nitrate contamination by illegal manure dumping in the leakage cave. According to a Bayesian mixing model, the contribution of manure wastewater was 33.5 to 81.8% as of 2015–2018, with the rest from fertilizers. Meanwhile, the groundwater ages showed negative correlations with both nitrate levels (r = –0.90) and δ15NNO3 values (r = –0.74) on a log scale, consistent with the increasing N release from livestock farming since the 1960s. In particular, the median value of δ15NNO3 rapidly increased to 9.2‰ in groundwater recharged between the late 1970s and early 1990s when N production exponentially increased, implying a significant effect of livestock farming after the 1980s. Groundwater quality is expected to deteriorate over the next several decades based on the groundwater ages (> 23.5 years), the increased N production from livestock farming, and the legacy effect of N. Long-term groundwater management plans (> 25 years) are required to decrease N loads in the study area, because it takes time for management practices to take effect. The study results are a good reference for groundwater management in regions with a source shift to livestock farming under intensive livestock production systems. Moreover, the chronological study using historical N production, groundwater age data, and dual nitrate isotopes can be applied to other regions with multiple N sources and their shifting for identifying sources and estimating time lags.

Consideration of change over time in nuclear accident consequence assessment to support optimization of long-term remediation strategy

Recent studies on nuclear accident consequence assessments that can cover consequences to both people and the environment, cannot capture the change of consequences over time, and vice versa. This study aims to design a framework of nuclear accident consequence assessment that can cover major consequences to people and the environment, and capture the long-term evolution of those consequences. Major long-term accident consequences are quantified using the cost per severe accident. Annual changes of key parameters are monitored to capture the change of each consequence over time. A case study with a hypothetical long-term loss of all AC power in a virtual BWR near Bangkok is conducted. Monitoring of the change of consequences over time leads to a different picture of overall accident consequences. Though decontamination takes up a large share of the cost per severe accident, its effects significantly decrease in several years. Radiation effects then dominate the overall accident consequences from the second decade onward. Parameter survey reveals the effectiveness of limiting and delaying decontamination in reducing the overall accident consequences in initial stage (first two years) and later stage (up to a decade), respectively. This time-dependent nuclear accident consequence assessment framework will be useful for long-term nuclear accident aftermath management planning.

Impact of climate change on the spatial distribution of endemic legume species of the Guineo-Congolian forest, Africa

Legumes (family Leguminosae) are an economically important and widely distributed species found in several regions of the world, including the Guineo-Congolian (GC) forest region. Recent studies have reported the impact of climate change on plant biodiversity. Thus, understanding the distribution pattern of the endemic legume species of the GC region under current and future climate scenarios are imperative for long-term conservation management plans. We used 762 occurrence data of the 237 endemic legume species to elucidate the habitat suitability and impact of climate change on the species. Analyses used an ecological niche modeling ensemble method to map the current and future (2050–2070) distribution patterns of the endemic legumes under the RCP 4.5 scenario. Further, we generated the ensemble of four different species distribution modeling methods to predict areas where climatically suitable regions is lost or gained under future climate change. The model predicted the current suitable areas for endemic legumes to be Southern Cameroon, Equatorial Guinea, Gabon, Republic of Congo (COG), and Democratic Republic of Congo (DRC). Our findings indicate precipitation of Warmest Quarter and seasonality as the significant climatic variables affecting the habitat suitability of endemic legumes in the GC regions. Results showed areas such as the coastal region of Cote d' Ivoire, southwest province of Cameroon, Central African Republic, COG (Ngounnie), central DRC, and southern Nigeria will experience >40% loss of climatically suitable areas by 2050. Also, species such as Baphia maxima, and Psophocarpus scandens were projected to experience a 70% reduction in their climatically suitable areas under future climate scenarios. Our study concludes that the projected distribution of the endemic legume species in the GC region will consequently decline in the future due to the gross effect of climate change. The anticipated changes in the distribution patterns of the endemic legumes could have significant ecological and socio‐economic significance. Therefore, we recommend improved conservation to protect the endemic legume species and its associated habitats in GC forest.

Long-term food waste management in Phnom Penh utilizing a system dynamics modeling approach

Phnom Penh has a high number of people. With more people, it is expected that food waste issues will be severe. To properly manage food waste, it is necessary to identify the key factors affecting food waste management, and examine the interactions among those key factors to effectively plan for long-term management. This study develops a dynamics model of food waste management, considering vegetables as the main waste, to examine the trends of food waste in Phnom Penh and plan for long-term management. The developed dynamics model considers two types of waste, household and retailer wastes. The simulation results reveal that most food wastes are from households. They are mainly from preparation processes and inappropriate packing sizes. The results show that with a smaller percentage of waste in preparation processes, food wastes going to a landfill decrease. The use of smaller-size packs (250 g and 350 g) also helps to minimize food wastes. The simulation results also suggest the use of biodigesters, to convert food waste to energy and reduce landfill waste in the long term. Local communities, local authorities, and governments can use this study to plan for long-term food waste management, to reduce food waste and mitigate landfill problems.