BURA Collection:

Environmental assessment of chemical contamination from abandoned coal and mineral mines

2025-01-01T00:00:00Z

Title: Environmental assessment of chemical contamination from abandoned coal and mineral mines Authors: Ekhareafo, Ushemegbe Rita Abstract: Abandoned mine lands (AMLs) are enduring sources of environmental pollution due to the release of toxic substances like metals, metalloids, organic and organometallic pollutants into the environment. These substances are transported through various processes such as acid mine drainage that aid the movement of pollutants across compartments and are driven by the pollutants' physicochemical properties, environmental conditions and the physical state of the abandoned mine. Chemicals released can be toxic, bioaccumulate, and persist; hence, highly polluted mine lands may pose significant ecological and human health risks. Worldwide, it is estimated that there are over a million abandoned mines. Nigeria is no exception, with over 1500 abandoned mines identified to date across many states, and so far, only a few have been reclaimed due to the high cost of restoration. This research focused on the environmental assessment of chemical contamination from abandoned coal and mineral mines in Nigeria. A systematic evidence map protocol was developed to evaluate current methods for assessing chemical contamination risks from abandoned coal and lead-zinc mines. The protocol was applied to review the evidence, which revealed that current AML risk assessment methods use contaminated land risk indices to evaluate chemical risk. Furthermore, the review identified evolving data-driven and probabilistic risk assessment methods, including logistic and linear regression models, which are emerging risk assessment approaches in AML chemical risk assessment. At the same time, Bayesian Kernel Machine Regression (BKMR), cumulative probability distribution analyses for HI, and Incremental Lifetime Cancer Risk (ILCR) have been reported for mixture risk assessment, and the study showed the relevance of bioindicator-based assessments for validating predictions from chemical-based assessments. A major aim of the project was to assess the chemical contamination and associated ecological and human health risks at coal and lead-zinc mines in Nigeria. In this phase of the research, environmental samples were collected from two abandoned lead-zinc mines at the Gimbi/Rikaya site in Plateau and the Abakaliki site in Ebonyi. The case study on abandoned coal mines was undertaken in Enugu, Nigeria. Site-specific contamination and ecological risk assessment at the Abakaliki and Gimbi/Rikaya sites revealed that both sites were heavily contaminated with Pb, Zn, and Cd, with higher concentrations at Abakaliki. Spatial distributions followed the pattern tailings > sediment > soil, with tailings as the primary contamination source. Sequential extraction confirmed that Pb, Cd, and Zn occur mainly in the exchangeable and reducible fractions, indicating high mobility and bioavailability, particularly in Abakaliki soils, where >34% of Pb occurred in mobile forms. In contrast, Pb mobility was lower at Gimbi, with only about 6% of F1 in the soil. Dissolved metals, Pb, Zn, Ni, Cu, and Mn in surface water at Abakaliki exceeded the environmental quality standards (EQS) and also the Biotic Ligand Model (BLM) bioavailability values. In contrast, only Zn exceeded EQS and bioavailability values at Gimbi. Ecological risk indices (Er, RI) and cumulative risk scores (CRS) indicated very high risk at Abakaliki and considerable risk at Gimbi, with Cd, Pb, and Zn as the dominant risk drivers. Chemical contamination and human health risk assessment (HHRA) at the Onyeama abandoned coal mine revealed the presence of both heavy metals and polycyclic aromatic hydrocarbons in soil, tailings, and water at varying concentrations. Fe, Mn, Zn, and Pb were the dominant metals of concern, reflecting inputs from historical mining residues and secondary weathering. The ΣBaPeq value (0.86 mg TEQ/kg) exceeded the Canadian Soil Quality Guideline (0.6 mg TEQ/kg), with BaP and DBA contributing substantially to the toxic load. The HHRA indicated ingestion and dermal contact as the dominant exposure pathways. Waterborne exposure contributed the highest non-carcinogenic and carcinogenic risk, with cumulative HI and CR values exceeding acceptable thresholds, particularly for children, highlighting their vulnerability. In contrast, soil and tailings contamination presented relatively lower cumulative HI and CCR. Overall, these findings confirm that abandoned Pb/Zn and coal mines pose both ecological and human health risks to inhabitants living on or near abandoned mines, pointing to the need for targeted management measures, including the containment of tailings, remediation of contaminated sediments, and monitoring of surface and groundwater pathways, to mitigate long-term ecological and human health impacts. Description: This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London

Machine learning approaches to understand the uptake and elimination of anthropogenic stressors in animal health

2025-01-01T00:00:00Z

Title: Machine learning approaches to understand the uptake and elimination of anthropogenic stressors in animal health Authors: Uhlhorn, Jasmin Abstract: The detection of pharmaceuticals in aquatic ecosystems raises questions about their potential effects on non-target organisms. However, environmental concentrations do not directly reflect the internal body burden of organisms. As part of this work, an investigation of contaminants of emerging concern in a coastal ecosystem as well as in marine biota highlighted this, with internal and surface water concentrations differing substantially. The gap may be linked to both environmental conditions and compound-specific uptake and elimination processes, which affect their bioaccumulation potential. Laboratory-based studies to understand compound-dependent uptake and elimination kinetics have traditionally focused on fish. In line with the 3Rs principle and regulatory efforts to move away from vertebrate testing, and to broaden taxonomic coverage, this work aimed to assess the potential of the invertebrate model species Daphnia magna to be used in mixture-based exposures as a high-throughput alternative. This necessitated the development and validation of a broad targeted analytical method for the determination of multi-class pharmaceuticals in D. magna, which had not previously been developed. This work successfully developed a method applicable across multiple pharmaceutical classes, capable of quantifying more than 50 compounds to acceptance criteria defined by ICH method validation guidelines. Mixture toxicokinetic exposures were performed, ranging from a single compound to simultaneous exposure of up to 50 compounds, and toxicokinetic profiles were successfully derived for 49 pharmaceuticals. Pharmaceuticals generally exhibited low bioconcentration potential with the majority of compounds having bioconcentration factors (BCFs) of <60 L kg-1 dry weight (dw), yet values ranged from 2 to >10,000 L kg-1 dw. The broad range highlights the importance of considering internal exposure when assessing hazard and subsequent risk. The generated toxicokinetic data was applied to machine learning models alongside published fish BCF data. The models achieved good performance for fish but showed limited predictive ability for D. magna. Mechanistic evaluation confirmed that models identified established properties and relationships that are linked to bioaccumulation and membrane permeability (logP, TPSA), demonstrating their ability to capture relevant processes when sufficient representative data is available. Overall, this work highlighted the potential of mixture-based approaches in the non-vertebrate organism D. magna to enable higher-throughput bioconcentration assessment. Utilising this high-throughput testing could rapidly generate ecotoxicity data to fulfil regulatory requirements and enable in silico modelling approaches to potentially replace animal testing in the future. Description: This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London

Advancing construction waste management in Kuwait: A novel strategic technological framework for circular and sustainable practices

2025-01-01T00:00:00Z

Title: Advancing construction waste management in Kuwait: A novel strategic technological framework for circular and sustainable practices Authors: Alraqeb Alazemi, Hanan Salem Abstract: The construction sector in Kuwait is experiencing rapid expansion, yet Construction and Demolition Waste (CDW) management remains inefficient, with over 85% of CDW still sent to landfills and only about 15 % recycled. This reliance on linear "take-make-dispose" waste practices contradicts Kuwait Vision 2035 sustainability goals and global best practices in circular construction. The industry faces significant regulatory gaps, technological underutilisation, economic disincentives, and stakeholder resistance to change, all limiting the adoption of sustainable waste management strategies. To address these challenges, this study develops a comprehensive integrated technological framework that leverages Building Information Modelling (BIM), 3D Concrete Printing (3DCP), and On-Site Recycling (OSR) to enhance waste tracking, optimise material reuse, and reduce landfill dependency. The research employs a mixed-methods approach underpinned by a pragmatic philosophy. It combines a quantitative survey of 129 construction stakeholders with qualitative insights from 82 semi-structured interviews, supplemented by policy analysis and two in-depth case studies in public-sector construction projects managed by the Ministry of Public Works (MPW) and the Public Authority for Housing Welfare (PAHW). The study is grounded in Circular Economy (CE) principles and the 4R waste hierarchy (Reduce, Reuse, Recycle, Recover), providing a theoretical foundation for the proposed framework. The findings reveal critical inefficiencies in Kuwait’s CDW management system, including weak regulatory enforcement, inadequate financial incentives, and very low adoption of digital technologies. Stakeholder insights confirm that a lack of awareness and persistent resistance to change further hinder the implementation of BIM, 3DCP, and OSR. As a solution, this study proposes an integrated BIM–3DCP–OSR framework tailored to Kuwait’s construction sector. BIM is employed for real-time waste monitoring and material lifecycle tracking, 3DCP for sustainable material utilisation and reduction of formwork waste, and OSR for decentralised recycling at project sites. The framework was examined and refined through expert validation interviews, document analysis, and theoretical alignment with CE principles and the UN Sustainable Development Goals (SDGs). The results demonstrate the feasibility and potential of integrating these technologies to significantly increase material recovery rates, reduce reliance on virgin resources, and divert waste from landfills. The framework provides a scalable model that can be adapted beyond Kuwait, particularly in the GCC and MENA regions, where similar CDW management challenges persist. This research contributes to both theory and practice by bridging digital construction technologies with sustainability principles and offering a replicable model for data-driven circular CDW management. The recommendations include policy measures for mandatory BIM-based waste tracking, the development of 3DCP material standards, and stricter enforcement of on-site recycling to accelerate the transition to circular construction. The findings and recommendations align with Kuwait Vision 2035 and SDGs 9, 11, 12, and 13. supporting Kuwait’s national sustainability commitments. Actionable recommendations are provided for the Kuwait Environment Public Authority (EPA) to update regulations, incentivise innovation, and build capacity for sustainable CDW management. The thesis concludes by emphasising the novelty of the integrated framework and suggesting avenues for future research, including large-scale economic feasibility assessments, integration of emerging technologies (AI, IoT) for waste tracking, and the role of public–private partnerships in scaling circular construction practices. Description: This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London

An assessment of the unintended consequences of structural coastal flood protection

2026-01-01T00:00:00Z

Title: An assessment of the unintended consequences of structural coastal flood protection Authors: Breen, Morgan James Abstract: This thesis investigates the unintended socio-hydrological consequences of structural coastal flood protections (SCFPs) and assesses the implications for coastal flood risk management strategy in the UK. Climate change, and the continued urban development of flood exposed areas can exacerbate coastal flood risk, and thus flood risk management authorities often tend towards structural coastal flood protection measures to minimise losses. However, these structurally proactive measures can lead to infrastructural lock-ins, whereby the decrease in flood probability from the defence can lead to increased urban development and population, ultimately leading to higher losses due to an inundation event. This process has been referred to as the Safe Development Paradox (SDP), a cross-cutting science-practice-policy challenge that requires a systematic understanding in the context of increased uncertainty associated with climate change and the United Nations Sustainable Development Goals. However, literature of the phenomena is limited, compounded by a lack of consistent terminology, limited geographic distribution, and a skewed emphasis on fluvial flooding. Moreover, despite being an island nation, the UK, to date, has had very little research conducted into these unintended consequences of structural flood protection. This thesis developed and applied a methodology that captures these coupled human-flood processes, by integrating well-established methods from other spheres of flood risk assessment in a novel way to explore the currently poorly understood phenomena in coastal settings. The study contributes to addressing this knowledge gap based on insights from three contrasting UK case studies: Portsmouth, Weston-super-Mare, and Southport. Differential analysis of historic LiDAR Digital Surface Models (DSMs) was used to identify temporal changes in the urban landscape to create a DSM of Difference (DoD), representing elevation change between two locations over time. Geostatistical testing, specifically t-tests, were then used to infer statistical significance of changes in urban development. The results reveal a consistent pattern: following completion or improvement of large-scale SCFPs, there is subsequent, and statistically significant, increases in coastal population and urban development within/near flood-exposed areas in all case studies, contrary to the limited flood-exposed development in neighbouring settlements, with no comparable defences constructed, or upgraded, during the same period. On average, new urban development occurs approximately 2 years after the completion of coastal flood defence projects. These data were then inputted into a newly developed agent-based model (ABM) that simulates futures changes under different climate scenarios. The results demonstrate that each SCFP project led to an initial decrease in Affected Population (AfP) following implementation, confirming the intended immediate benefits of flood risk reduction. However, long-term projections revealed significant unintended consequences under the scenarios where SCFPs were exceeded by Extreme Coastal Water Levels (ECWLs). For Southport and Weston-super-Mare, the ABM output shows a dramatic increase in AfP once ECWL surpassed the SCFP crest height, affecting a larger population than those initially protected, primarily due to the increased population growth behind the defences and the larger flood extent. Portsmouth, however, exhibited a more limited increase in AfP, attributed to its high urban density and limited room for further development behind the defences. This highlights how pre-existing land-use and population density can act as brakes on the unintended consequences of SCFPs. The thesis concludes with a recommendation for future flood risk managers and policymakers to be aware of these unintended socio-hydrological consequences. SCFPs are crucial assets, and their construction and maintenance will continue to play an integral role in coastal adaptation to climate change, particularly in highly developed urban settlements. This thesis does not attempt to provide a comprehensive predictive modelling tool for planning, nor a detailed analysis of real estate markets, but instead focuses on socio-hydrological interactions of population change and SCFP. However, new SCFP design and implementation need to account for their long-term unintended consequences on communities and climate adaptation planning. In the short-term, flood risk communication provides a means of tackling these risks, improving flood memory, awareness, and preparedness. Furthermore, in the longer term a more holistic cost-benefit analysis and spatial planning strategy, internalising these factors should be utilised in order to create more sustainable and resilient coastal communities in the UK. Description: This thesis was submitted for the award of Master of Philosophy and was awarded by Brunel University London