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Item Household attributes, motivational factors, and sources of motivation influencing flood preparedness of vulnerable population groups(Higher Education Press, 2026) Goonetilleke, AshanthaExtreme disaster events, particularly floods, impact individuals, households, and communities differently depending on a range of factors. Some residents are more vulnerable than others to floods, hence urgent action is needed to improve preparedness of vulnerable groups to reduce potential impacts of flooding. To achieve this, it is important to assess household flood preparedness, and identify the influence of household-level attributes on flood preparedness. Using a large-scale community survey, this study investigated how key household attributes such as evacuation assistance, Internet access, and key motivational factors and sources of motivation such as personal and social networks influence flood preparedness among vulnerable households. Households were categorized into three levels of vulnerability (high, medium, and low) by combining household economic capacity, as measured by household monthly expenditure, and the presence of vulnerable family members. Six key findings emerged: (1) Highly vulnerable households showed higher resilience to floods, and flood preparedness levels are independent of household vulnerability levels; (2) Self-reported household flood preparedness is positively influenced by learning from past disaster experience; (3) Financial and time commitments, and a sense of urgency for household-level flood preparedness are key intrinsic motivational factors that influence flood preparedness; (4) Access to reliable Internet can be used as a proxy to predict the degree of household flood preparedness; (5) Higher levels of awareness and knowledge of flood preparedness were reported despite low levels of community consultation; and (6) Self-motivation is the key source of motivation for flood preparedness. The study findings will support key institutional stakeholders such as local governments to devise strategies to strengthen the flood resilience of vulnerable households and communities.Item Modelling land use influence on polymer-specific microplastics abundance and transportation from terrestrial to aquatic environments(Elsevier, 2026-04) Goonetilleke, AshanthaPlastic waste has reached a major environmental crisis level. Human exposure to microplastics (MPs)– particles <5 mm – is linked to toxicity, oxidative stress, inflammatory responses, neoplastic change, and numerous chronic health effects. Effective mitigation requires a thorough understanding of factors that govern MP accumulation and transport. While quantitative analyses at the polymer level remain limited, the role of land use patterns in shaping polymer abundance and movement is especially underexplored. This study addresses this knowledge gap by characterising and quantifying polymer-specific MP abundance (polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET) and polyvinyl chloride (PVC)) in freshwater across four urban land uses (industrial, commercial, residential, and natural). Bayesian Network models were developed for two urban catchments, and a pooled model generated generalised estimates across both basins. PET and PP dominate industrial areas, while commercial areas show high PE, PVC, and PS levels. Residential areas contain elevated levels of all five polymers, and the natural regions are characterised by PE, PVC, and PS. These distinct polymer signatures reflect local activities associated with each land use. Regression outputs from the pooled model enabled quantification of individual polymer loads and prediction of concentrations at unsampled sites based on known land use profiles. Strong relationships were found between abundance and commercial/industrial land uses than with residential and natural settings. Consequently, mitigation strategies targeting industrial and commercial sectors will yield the greatest reductions in MP emissions. Study outcomes support targeted source control and efficient monitoring designs, and robust policy development for curbing microplastic pollution.Item Catchment characteristics and land-use influence on microplastics distribution in freshwater sediments(Elsevier, 2026-04) Goonetilleke, AshanthaThis study examines microplastic contamination in freshwater sediments from three urban creeks in Brisbane, Australia. A dual-density extraction method, validated by recovery experiment (85–100%), was used to extract microplastics, followed by identification via light microscope, micro- FTIR and SEM. Kedron Brook showed the highest median abundance (4400 items/kg), followed by Bulimba Creek (4100 items/kg) and Enoggera Creek (2800 items/kg). Site-wise assessment revealed three distinct spatial patterns among the creeks, likely reflecting differences in runoff dynamics, surrounding anthropogenic activities, catchment elevation profile, and land-use. Microplastics abundances were higher at downstream and estuarine sites, particularly within urbanised zones. Polymer analysis identified polyethylene (PE), polypropylene (PP) and Polymethyl methacrylate (PMMA) as the most dominant types. Linear mixed-effects modelling identified creek system (p = 0.018) and sampling round (p = 0.003) as significant predictors of microplastic abundance, while between-site variability was reflected by a site-level random-effect variance of 0.0116. Multivariate analyses revealed distinct land-use associations, with residential and commercial land-uses significantly associated with PP and polyester, and industrial land-use associated with PP, polystyrene (PS), and polyester, whereas natural land-use showed no significant associations with any polymer type. Overall, urban land-use types exerted a stronger influence compared to natural land-use on microplastic distribution in freshwater sediments.Item Human health risk assessment of toxic chemical pollutants in stormwater(Springer, 2023) Goonetilleke, AshanthaThis book presents a detailed analysis in relation to human health risk assessment of the main toxic chemical pollutants in urban stormwater generated from urban traffic and land use activities. The knowledge presented in this book was derived based on comprehensive experimental investigations including field sampling, laboratory testing, mathematical modelling, spatial analysis and multivariate and univariate statistical data analyses. The key highlights of the book include the quantitative assessment of the human health risk posed by key toxic chemical pollutants in urban stormwater and the development of linkages between risk and traffic and land use. Additionally, a suite of mathematical equations are presented to predict human health risk based on traffic and land use characteristics through mathematical modelling. These outcomes can significantly assist in effective stormwater risk management under changing traffic and land use in the urban environment. The knowledge presented is of particular interest to readers such as stormwater treatment design specialists, decision-makers and urban planners since these outcomes provide practical suggestions and recommendations for effective urban stormwater treatment design.Item Distribution and variation of metals in urban river sediments in response to microplastics presence, catchment characteristics and sediment properties(Elsevier, 2023-01) Goonetilleke, AshanthaDespite well documented studies on metal pollutants in aquatic ecosystems, knowledge on the combined effects of catchment characteristics, sediment properties, and emerging pollutants, such as microplastics (MPs) on the presence of metals in urban river sediments is still limited. In this study, the synergistic influence of MPs type and hazard indices, catchment characteristics and sediment properties on the variability of metals present in sediments was investigated based on a typical urban river, Brisbane River, Australia. It was noted that the mean concentrations of metals in Brisbane River decreases in the order of Al (94,142 ± 12,194 μg/g) > Fe (62,970 ± 8104 μg/g) > Mn (746 ± 258 μg/g) > Zn (196 ± 29 μg/g) > Cu (50 ± 19 μg/g) > Pb (47 ± 25 μg/g) > Ni (25 ± 3 μg/g) while the variability of metals decreases in the order of Pb > Cu > Mn > Al > Ni > Zn > Fe along the river. According to enrichment factor (Ef) contamination categories, Mn, Cu and Zn exert a moderate level of contamination (Ef > 2), while Fe, Ni, and Zn show slight sediment pollution (1 < Ef < 2). In the case of Pb, extremely high enrichment (Ef > 3) was found at sampling locations having a high urbanisation level and traffic related activities. Crustal metal elements (namely, Al, Fe, Mn) were found to be statistically significantly correlated with sediment properties (P < 0.05). Anthropogenic source metals (namely, Cu, Ni, Pb, Zn) were observed to be highly correlated with catchment characteristics. Additionally, the presence of metals in sediments were positively correlated with MPs concentration, and negatively correlated with MPs hazard indices. The outcomes of this study provide new insights for understanding the relationships among metals and various influential factors in the context of urban river sediment pollution, which will benefit the formulation of risk assessment and regulatory measures for protecting urban waterways.Item Environmental risks posed by microplastics in urban waterways environmental risks posed by microplastics in urban waterways(Springer, 2023) Goonetilleke, AshanthaThis book presents comprehensive knowledge regarding the spatial and temporal distributions, influential factors, interactions with coexisting contaminants, migration behavior, and environmental risk posed by microplastics (MPs) in urban waterways. It provides a novel theoretical approach for the combined risks from MPs and coexisting contaminants, and advanced three-dimensional modeling techniques for different MPs’ dispersal and transport behaviors in urban waterways. Additionally, this book presents a scientifically robust investigation on the correlations between various influential factors and heterogeneity in relation to MP presence in river systems. The new knowledge presented would be of particular interest to readers such as urban water management professionals, urban plastic waste regulators, decision-makers, urban planners, and water environment quality model developers, as it provides practical solutions and recommendations for plastic-polluted river quality improvement from a risk management perspective.Item Case study: Risks posed by MPs presence and transport in Brisbane River sediments, Australia(Springer, 2023-03) Goonetilleke, AshanthaThis chapter presents the outcomes of a case study which focused on understanding the environmental risks and transport processes of microplastics (MPs) in urban river sediments. Sediment samples obtained from twenty-two sampling points along the Brisbane River, Australia, over four different climatic seasons revealed relatively high concentrations of MPs in the sediments, with abundance ranging from 0.18 to 129.20 mg kg−1. The environmental risk posed by MPs was assessed by analysing their impacts on other pollutants present in the sediments, namely, nutrients (TC, TN, TP) and fourteen metals (Al, As, Cr, Co, Cu, Fe, Mg, Mn, Ni, Cd, Se, Sr, Zn, Pb) commonly present in urban aquatic environments. All three nutrient parameters were found to have a strong positive relationship with MPs concentration, while negatively correlated to MPs hazard index. The tested metals in Brisbane River sediments were observed to be correlated more with MPs hazard index rather than MPs concentration. Additionally, a three dimensional hydrodynamic and particle transport modelling framework developed showed that sedimental MPs with lower density and slow settling velocity (such as PE and PP) have higher mobility, while dense MP particles (such as PA and PET) are more likely to accumulate in the river sediments close to source points.Item Factors influencing MPs presence in urban waterways(Springer, 2023-03) Goonetilleke, AshanthaThe presence and distribution of various MP particles exhibit inconsistent patterns in urban waterways. Factors including land use type and anthropogenic activities are regarded as the dominant contributor of MPs in urban waterways as these are the major emission sources of plastic pollution. In addition to the diverse origins of MP pollution, environmental factors such as hydrodynamic conditions, photothermal degradation and the interactions between MPs and natural systems influence the presence of MPs by altering their properties such as size, shape and density. This chapter discusses the influence of emission sources, namely, land-based, aquatic-based and atmospheric-based sources, and environmental factors, namely, hydrodynamic conditions, photothermal degradation, and microorganism colonisation on the presence of MPs abundance and types in urban waterways. Such understanding will guide environmental risk management and critical decision-making related to source tracking, and impact mitigation of MP pollutants in urban aquatic systems.Item Risk associated with MPs in urban waterways(Springer, 2023-03) Goonetilleke, AshanthaMPs are complex environmental contaminants as they bind to a wide range of other contaminants. MPs associated contaminants include toxic chemical compounds that are used as additives during the plastic manufacturing process and various contaminants such as organic compounds, metals and microorganisms that are adsorbed from the surrounding environment. The organic and inorganic contaminants attached to MPs will exert direct and indirect impacts on aquatic environments due to the presence and migration processes of MPs. This chapter provides a detailed discussion on the environmental risks of MPs in urban aquatic environments arising from the release/sorption mechanisms between MPs and common contaminants, namely, metals and organic compounds. Additionally, this chapter also identifies the impacts of MPs on aquatic microorganisms from a risk assessment perspective.Item Practical implications and recommendations for further research(Springer, 2023-03) Goonetilleke, AshanthaThis chapter provides a consolidated summary of the research study outcomes on the investigation of the environmental risks in relation to MPs occurrence and migration in urban waterways. The knowledge created is expected to provide practical guidance and recommendations for the formulation of effective management and mitigation strategies for MPs in urban aquatic environments. This chapter also identifies key areas where significant knowledge gaps exist in relation to MPs source tracking, interaction mechanisms (release and sorption capacity) with metals and organic contaminants, as well as the environmental consequences to urban waterways from a risk perspective.