Drivers of divergent assessments of bisphenol-A hazards to semen quality by various European agencies, regulators and scientists

The downward revision of the bisphenol A (BPA) Health-based Guidance Value (HBGV) by the European Food Safety Authority (EFSA) has led to disagreements with other regulatory agencies, among them the German Federal Institute for Risk Assessment (BfR). The BfR has recently published an alternative Tolerable Daily Intake (TDI), 1000-times higher than the EFSA HBGV of 0.2 ng/kg/d. While the EFSA value is defined in relation to immunotoxicity, the BfR alternative TDI is based on declines in sperm counts resulting from exposures in adulthood. Earlier, we had used semen quality deteriorations to estimate a BPA Reference Dose (RfD) of 3 ng/kg/d for use in mixture risk assessments of male reproductive health. We derived this estimate from animal studies of gestational BPA exposures which both EFSA and BfR viewed as irrelevant for human hazard characterisations. Here, we identify factors that drive these diverging views. We find that the fragmented, endpoint-oriented study evaluation system used by EFSA and BfR, with its emphasis on data that can support dose-response analyses, has obscured the overall BPA effect pattern relevant to male reproductive effects. This has led to a disregard for the effects of gestational BPA exposures. We also identify problems with the study evaluation schemes used by EFSA and BfR which leads to the omission of entire streams of evidence from consideration. The main driver of the diverging views of EFSA and BfR is the refusal by BfR to accept immunotoxic effects as the basis for establishing an HBGV. We find that switching from immunotoxicity to declines in semen quality as the basis for deriving a BPA TDI by deterministic or probabilistic approaches produces values in the range of 2.4-6.6 ng/kg/d, closer to the present EFSA HBGV of 0.2 ng/kg/d than the BfR TDI of 200 ng/kg/d. The proposed alternative BfR value is the result of value judgements which erred on the side of disregarding evidence that could have supported a lower TDI. The choices made in terms of selecting key studies and methods for dose-response analyses produced a TDI that comes close to doses shown to produce effects on semen quality in animal studies and in human studies of adult BPA exposures.

Residual waste management in London, England: a reality check

Residual waste is a key fraction of municipal solid waste generated, yet its management is poorly understood and has gained little attention over the past years. Using London as a case study, the present study analyses the amount of residual waste collected and managed to check on how well ahead the UK is in making progress on achieving the circular economy principles. The study found that 5 Mt of residual waste is reported to be managed in London, of which 3.5 Mt is managed via recovery operations and 1.59 Mt is managed via disposal operations. For the latter, landfills are the principal disposal option taking in 0.82 Mt of residual waste each year. Amongst the recovery options, incineration with energy recovery, is the most prevalent, accounting for the management of 1.44 Mt of residual waste. This highlights the presence of an important technological lock-in that could jeopardise UK's ability to achieve its net zero carbon ambition. It is worth noting that the data collated and analysed depicts the movements of residual waste rather than its final treatment, pointing to blind spots in the final fate of residual waste as well as potential double counting; both of which prevent decision- and policy-making. Therefore, the need for transparency in data recording and monitoring and the creation of a level playing field for all stakeholders involved in residual waste management are of paramount importance in gradually breaking reliance on destructive treatment processes. This could empower improved segregation of waste at source, and in turn, enable the better management of residual waste. The study underlines that residual waste has a significant role to play in making the transition to a circular economy and therefore is imperative to pave the way for future policy direction on residual waste management.

Unpacking the complexity of the polyethylene food contact articles value chain: A chemicals perspective

Polyethylene (PE) is the most widely used type of plastic food packaging, in which chemicals can potentially migrate into packaged foods. The implications of using and recycling PE from a chemical perspective remain underexplored. This study is a systematic evidence map of 116 studies looking at the migration of food contact chemicals (FCCs) across the lifecycle of PE food packaging. It identified a total of 377 FCCs, of which 211 were detected to migrate from PE articles into food or food simulants at least once. These 211 FCCs were checked against the inventory FCCs databases and EU regulatory lists. Only 25% of the detected FCCs are authorized by EU regulation for the manufacture of food contact materials. Furthermore, a quarter of authorized FCCs exceeded the specific migration limit (SML) at least once, while one-third (53) of non-authorised FCCs exceeded the threshold value of 10 μg/kg. Overall, evidence on FCCs migration across the PE food packaging lifecycle is incomplete, especially at the reprocessing stage. Considering the EU's commitment to increase packaging recycling, a better understanding and monitoring of PE food packaging quality from a chemical perspective across the entire lifecycle will enable the transition towards a sustainable plastics value chain.

Keep circularity meaningful, inclusive and practical: A view into the plastics value chain

New policies to promote the circular economy have created an urgent need for businesses and public authorities to quantify and monitor the level of circularity of materials, components and products. However, flows of materials, components and products through society are inherently complex, involving intricate value chains, many stakeholders, and interests. We argue that current actions may be overly focused on superficial effects, and losing sight of true circular economy goals. Using plastic packaging as an example, the present contribution deliberates the questions, "does measuring circularity address its goals?", "does it cover new technologies and regional specificities?", and "can its goals be addressed with simple assessment approaches?". In answering these questions, we argue that there is an impending risk of cementing policy and infrastructures that may not contribute to true sustainability. Furthermore, future technologies and developing regions are hardly included in the current circularity strategies. To further spark a discussion on the challenge of simplicity, we present a scorecard which can help incumbents to approximate the level of sustainable circularity of their products.

An overview of the occurrence, fate, and human risks of the bisphenol-A present in plastic materials, components, and products

With over 95% of bisphenol-A (BPA) used in the production of polycarbonate (PC) and epoxy resins, termed here as BPA-based plastic materials, components, and products (MCPs), an investigation of human exposure to BPA over the whole lifecycle of BPA-based plastic MCPs is necessary. This mini-review unpacks the implications arising from the long-term human exposure to BPA and its potential accumulation across the lifecycle of BPA-based plastics (production, use, and management). This investigation is timely and necessary in promoting a sustainable circular economy model. Restrictions of BPA in the form of bans and safety standards are often specific to products, while safety limits rely on traditional toxicological and biomonitoring methods that may underestimate human health implications and therefore the "safety" of BPA exposure. Controversies in regards to the: (a) dose-response curves; (b) the complexity of sources, release mechanisms, and pathways of exposure; and/or (c) the quality and reliability of toxicological studies, appear to currently stifle progress toward the regulation of BPA-based plastic MCPs. Due to the abundance of BPA in our MCPs production, consumption, and management systems, there is partial and inadequate evidence on the contribution of BPA-based plastic MCPs to human exposure to BPA. Yet, the production, use, and end-of-life management of plastic MCPs constitute the most critical BPA source and potential exposure pathways that require further investigation. Active collaboration among risk assessors, government, policy-makers, and researchers is needed to explore the impacts of BPA in the long term and introduce restrictions to BPA-based MCPs. Integr Environ Assess Manag 2023;19:45-62. © 2022 SETAC.

Unpacking the complexity of the PET drink bottles value chain: A chemicals perspective

Chemicals can migrate from polyethylene terephthalate (PET) drink bottles to their content and recycling processes may concentrate or introduce new chemicals to the PET value chain. Therefore, even though recycling PET bottles is key in reducing plastic pollution, it may raise concerns about safety and quality. This study provides a systematic evidence map of the food contact chemicals (FCCs) that migrate from PET drink bottles aiming to identify challenges in closing the plastic packaging loop. The migration potential of 193 FCCs has been investigated across the PET drink bottles lifecycle, of which 150 have been detected to migrate from PET bottles into food simulants/food samples. The study reveals that much research has focused on the migration of antimony (Sb), acetaldehyde and some well-known endocrine-disrupting chemicals (EDCs). It indicates and discusses the key influential factors on FCCs migration, such as physical characteristics and geographical origin of PET bottles, storage conditions, and reprocessing efficiency . Although, safety and quality implications arising from the recycling of PET bottles remain underexplored, the higher migration of Sb and Bishphenol A has been reported in recycled (rPET) compared to virgin PET. This is attributed to multiple contamination sources and the variability in the collection, sorting, and decontamination efficiency. Better collaboration among stakeholders across the entire PET bottles lifecycle is needed to ensure sustainable resource management and food contact safety of rPET.

The challenges of Covid-19 pandemic on improving plastic waste recycling rates

The plastic system is burdened with many inefficiencies that have been exposed, and exacerbated, by the outbreak of the coronavirus (SARS-CoV2) pandemic in December 2019, widely known as COVID-19, and which threaten society's commitment to transition to a sustainable plastics economy. This perspective aims to depict the structural and systemic inefficiencies of the plastics system, and illuminate: (a) the vulnerability of the recycling sector to macroeconomic - particularly to oil price - shocks; (b) the economics of the recycling system; (c) the political dimensions of the plastics sector. It emphasises that is unwise to think about plastics recycling as an insular and linear problem, due to the complexity and interconnectedness of different parts of the plastic system that affect and are affected by the intertwined processes, stakeholders and values. That said, the transition to a sustainable plastics system requires an integrated, knowledge-based systems approach that interrogates the dynamics and causal-effect relationships of the interconnected challenges. This analytical scrutiny can indicate where interventions are needed in the plastics system towards creating transformational change.

A systems thinking approach to understanding the challenges of achieving the circular economy

Circular economy (CE) is extensively discussed around the globe. Presently, discussions are mostly concerned with the importance of achieving CE and the benefits associated therewith, with the various barriers surrounding its implementation being less debated. Understanding the context in which circularity can flourish is a prerequisite in building the capabilities to deal with the multi-faceted challenges that currently hamper progress in closing the material, component and product loops. In this study, we discuss the importance of systems thinking in understanding the way resource recovery systems operate, and in promoting deep transformational change. We suggest that transformational change needs to go beyond closing materials, components and products (MCPs) loops, and promote sustainability in the way resources are exploited, used and managed throughout the system. By adopting a system of systems approach, we postulate that there are five interconnected sub-systems that need to be considered for supporting transitions to CE, namely, resource flows and provisioning service; governance, regulatory framework and political landscape; business activities and the marker; infrastructure and innovation; and user practices. This holistic approach provides a useful means to cutting through systemic complexity, and focuses on the dynamics between processes, values and actors in the value chain, and their dependence on cultural, spatial and temporal characteristics. We conclude that a systems-based approach can build up the capabilities required to identify and understand persistent linear trends and, in turn, support forward-thinking and time investment in enabling sustainable transitions. This, in turn, can help to align priorities and transform our current practices, speeding up the process of closing the MCP loops in a sustainable manner. Graphical abstract.

Opportunities, challenges and trade-offs with decreasing avoidable food waste in the UK

Around 6 million tonnes of edible food are being wasted (post-farm gate) in the UK each year. This fraction of edible wasted food is known as avoidable food waste. In a circular economy food is a valuable resource that must be captured at all stages of the food supply chain and, where possible, redistributed for consumption. This can prevent avoidable food waste generation, and dissipation of food's multidimensional value that spans environmental, economic, social, technical and political/organisational impacts. While the importance and benefits of surplus food redistribution have been well documented in the global literature, there are still barriers that prevent perfectly edible food from being wasted. This study looks at the main stages of the food supply chain, and amasses the opportunities, challenges and trade-offs associated with surplus food redistribution to the UK economy. It highlights points in the food system where interventions can be made, to improve food's circularity and sustainability potential. Stakeholder interrelations, regulatory and socio-economic aspects are discussed in relation to their influence on decreasing avoidable food waste. The main output from this work is a diagrammatic depiction of where challenges and trade-offs occur along the food supply chain, and how policy and socio-economic reforms are needed to maximise avoidable food waste prevention, and the surplus avoidable food redistribution in the food supply chain for social benefit.

An overview of the challenges and trade-offs in closing the loop of post-consumer plastic waste (PCPW): Focus on recycling

Recycling of post-consumer plastic waste (PCPW) is increasingly promoted as the means to achieving circular economy (CE). It converts plastic waste into a secondary material that can be fed back into the system, for use in the same or new components and products, with similar or lower functionality; hence "closing the loop". Up until today, research on examining the environmental impacts, economic implications and technicalities of plastic waste recycling deals with one particular aspect, or stage on the plastic value chain, lacking coherence and structure. To move this research forward, understanding the challenges and trade-offs in scaling up plastic waste recycling is necessary. Here, we bring together existing literature on the multi-faceted aspects of closing the plastic loop, critically debating on the multi-stakeholder endeavours of promoting circularity in the plastics value chain. We present an overview of how the design, production, collection and sorting of PCPW present challenges for plastic waste recycling, which in turn result to a number of trade-offs. We explain that the evaluation of the multi-dimensional implications of trade-offs arising from the PCPW recycling, is essential in measuring the long-term sustainability of resource recovery from waste systems. This work scrutinises the sustainability of closing the plastic waste loops and sets a future research agenda.

Quality of resources: A typology for supporting transitions towards resource efficiency using the single-use plastic bottle as an example

The growing British waste management sector has consistently voiced the need to improve the quality of waste streams and thus the value of secondary resources produced, in order to achieve higher reprocessing rates. Mismanagement of wastes that may lead to contamination and degradation of the recyclate feedstock constitutes one of the main barriers in the pathway to a circular economy. The sector has also repeatedly called upon manufacturers to collaborate in designing materials, components and products (MCPs) with properties that aid recovery, refurbishing, repair and recycling (e.g. separabilty of materials, clear labelling), as waste managers recognise the value of early engagement well before MCPs enter the supply chain (i.e. before MCPs are produced and distributed to the end user). Nonetheless, progress has been slow with regard to improved design for promoting components and products longevity and segregation at source when they reach their end-of-use or end-of-life stage in order to promote circularity. China's ban on imports of low quality recyclates at the end of 2017 marked the beginning of a new era in waste management. It drew attention to UK's dependence on export of low-value secondary resources, placing 'quality' in the spotlight. This article delves into the notion of quality; how quality is understood and assessed at different parts of the MCPs lifecycle, and how it might be systematically measured. A typology to distinguish avoidable and unavoidable designed and created characteristics at all stages of MCPs lifecycle is proposed to provide industry with a tool to design wastes out of the economy. The typology's application is demonstrated using the single-use plastic bottles as an example.

A multi-criteria sustainability assessment framework: development and application in comparing two food waste management options using a UK region as a case study

Preventing food wastage is a key element of sustainable resource management. But as food waste is still generated at high volumes, priority is placed on its proper management as a resource, maximising sustainability benefits. This study, by integrating a multi-criteria decision analysis with a sustainability assessment approach, develops a screening and decision support framework for comparing the sustainability performance of food waste management options. A structured process for selecting criteria based on the consideration of environmental, economic and social aspects related to region-specific food waste system planning, policy and management has been developed. Two food waste management options, namely the use of food waste disposal units, which grind food waste at the household's kitchen sink and discharge it to the sewer, and the anaerobic co-digestion of separately collected food waste with sewage sludge, were selected for comparison due to their potential to create synergies between local authorities, waste and water companies, with local circumstances determining which of the two options to adopt. A simplified process used for assessing and comparing the two food waste management options in the Anglian region in the UK, indicated that there are benefits in using the framework as a screening tool for identifying which option may be the most sustainable. To support decision-making, a detailed analysis that incorporates stakeholders' perspectives is required. An additional use of the framework can be in providing recommendations for optimising food waste management options in a specific region, maximising their sustainability performance.

Food flows in the United Kingdom: The potential of surplus food redistribution to reduce waste

The increasing amount of food waste generated as a direct consequence of its excessive production, mismanagement, and wasteful behaviors represents a real challenge in promoting resource efficiency. In the United Kingdom (UK), the lack of robust mass flow data hinders the ability both to understand and address food waste challenges and to devise long-term sustainable prevention strategies. In recognition of these challenges, this paper seeks to (i) provide insights into the UK's annual estimates of food mass flows, including imports, exports, distribution, consumption, surplus food production, and final disposal; and (ii) scrutinize the uptake and redistribution of surplus food as a potential food waste prevention strategy. Evidence collected from several enterprises and community-led initiatives in the UK, and London specifically, supports that there is an increasing potential of making a shift towards food redistribution and reuse. Further analysis has shown that the outreach of food redistribution initiatives in the UK is currently limited, possibly because redistribution efforts remain largely fragmented and independent from each other. It is concluded that a national commitment could be instrumental in encouraging the roll-out of this practice, and governmental support through fiscal incentives could lead to the development of a larger and coherent surplus food redistribution system, ultimately enabling food waste prevention and recovery of food's multidimensional value.

IMPLICATIONS

This paper deals with the topical issue of the increasing amount of food waste generated as a direct consequence of excessive production, mismanagement, and wasteful behavior, representing a real challenge in achieving sustainability and resource efficiency. Currently, only a small fraction of food is redistributed back into the system. Yet, a considerable fraction of food waste generated is edible; thus, better planning, storage, and coordination amongst the different stakeholders in the food supply chain is required in order to prevent its wastage and promote its reuse in accordance with the waste hierarchy.

Closing the loop on plastic packaging materials: What is quality and how does it affect their circularity?

While attention on the importance of closing materials loops for achieving circular economy (CE) is raging, the technicalities of doing so are often neglected or difficult to overcome. These technicalities determine the ability of materials, components and products (MCPs) to be properly recovered and redistributed for reuse, recycling or recovery, given their remaining functionality, described here as the remaining properties and characteristics of MCPs. The different properties of MCPs make them useful for various functions and purposes. A transition, therefore, towards a CE would require the utmost exploitation of the remaining functionality of MCPs; ideally, enabling recirculation of them back in the economy. At present, this is difficult to succeed. This short communication article explains how the remaining functionality of MCPs, defined here as quality, is perceived at different stages of the supply chain, focusing specifically on plastic packaging, and how this affects their potential recycling. It then outlines the opportunities and constraints posed by some of the interventions that are currently introduced into the plastic packaging system, aimed at improving plastic materials circularity. Finally, the article underpins the need for research that integrates systemic thinking, with technological innovations and policy reforms at all stages of the supply chain, to promote sustainable practices become established.

The use of smart technologies in enabling construction components reuse: A viable method or a problem creating solution?

The exploitation of Radio Frequency Identification (RFID) for tracking and archiving the properties of structural construction components could be a potentially innovative disruption for the construction sector. This is because RFID can stimulate the reuse of construction components and reduce their wastage, hence addressing sustainability issues in the construction sector. To test the plausibility of that idea, this study explores the potential pre-conditions for RFID to facilitate construction components reuse, and develops a guidance for promoting their redistribution back to the supply chain. It also looks at how integrating RFID with Building Information Modelling (BIM) can possibly be a valuable extension of its capabilities, providing the opportunity for tracked components to be incorporated into new structures in an informed, sound way. A preliminary assessment of the strengths, weaknesses, opportunities and threats of the RFID technology is presented in order to depict its current and future potential in promoting construction components' sustainable lifecycle management, while emphasis has been laid on capturing their technical, environmental, economic and social value. Findings suggest that the collection of the right amount of information at the design-construction-deconstruction-reuse-disposal stage is crucial for RFID to become a successful innovation in the construction sector. Although a number of limitations related to the technical operability and recycling of RFID tags seem to currently hinder its uptake for structural components' lifecycle management, future technological innovations could provide solutions that would enable it to become a mainstream practice. Taken together these proposals advocate that the use of RFID and its integration with BIM can create the right environment for the development of new business models focused on sustainable resource management. These models may then unlock multiple values that are otherwise dissipated in the system. If the rapid technological development of RFID capability can be allied to policy interventions that control and manage its uptake along the supply chain, the sustainable lifecycle management of construction components could be radically enhanced.

Post-consumer plastic packaging waste in England: Assessing the yield of multiple collection-recycling schemes

The European Commission (EC) recently introduced a 'Circular Economy Package', setting ambitious recycling targets and identifying waste plastics as a priority sector where major improvements are necessary. Here, the authors explain how different collection modalities affect the quantity and quality of recycling, using recent empirical data on household (HH) post-consumer plastic packaging waste (PCPP) collected for recycling in the devolved administration of England over the quarterly period July-September 2014. Three main collection schemes, as currently implemented in England, were taken into account: (i) kerbside collection (KS), (ii) household waste recycling centres (HWRCs) (also known as 'civic amenity sites'), and (iii) bring sites/banks (BSs). The results indicated that: (a) the contribution of KS collection scheme in recovering packaging plastics is higher than HWRCs and BBs, with respective percentages by weight (wt%) 90%, 9% and 1%; (b) alternate weekly collection (AWC) of plastic recyclables in wheeled bins, when collected commingled, demonstrated higher yield in KS collection; (c) only a small percentage (16%) of the total amount of post-consumer plastics collected in the examined period (141 kt) was finally sent to reprocessors (22 kt); (c) nearly a third of Local Authorities (LAs) reported insufficient or poor data; and (d) the most abundant fractions of plastics that finally reached the reprocessors were mixed plastic bottles and mixed plastics.

Technical properties of biomass and solid recovered fuel (SRF) co-fired with coal: Impact on multi-dimensional resource recovery value

The power plant sector is adopting the co-firing of biomass and solid recovered fuel (SRF) with coal in an effort to reduce its environmental impact and costs. Whereas this intervention contributes to reducing carbon emissions and those of other pollutants related with the burning of fossil fuel, it may also result in hidden impacts that are often overlooked. When co-firing, the physical and chemical properties of the mixed fuels and the subsequent technical implications on the process performance and by-products are significant. Interconnections between multiple values nested within four domains of value, i.e. environmental, economic, technical and social, mean that changes in the one domain (in the co-firing case, the technical one) can have considerable implications in the other domains as well. In this study, using a systematic and flexible approach to conceptualising multi-dimensional aspects associated with the co-firing of biomass and SRF with coal, we unveil examples of such interconnections and implications on overall value delivered through the use and recovery of waste resources. Such an analysis could underpin the selection of useful metrics (quantitative or semi-quantitative descriptors) for enabling a systemic multi-dimensional value assessment, and value's distribution amongst interconnected parts of resource recovery systems; key in enabling sound analysis and decision-making.

An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling

Over the last 60 years plastics production has increased manifold, owing to their inexpensive, multipurpose, durable and lightweight nature. These characteristics have raised the demand for plastic materials that will continue to grow over the coming years. However, with increased plastic materials production, comes increased plastic material wastage creating a number of challenges, as well as opportunities to the waste management industry. The present overview highlights the waste management and pollution challenges, emphasising on the various chemical substances (known as "additives") contained in all plastic products for enhancing polymer properties and prolonging their life. Despite how useful these additives are in the functionality of polymer products, their potential to contaminate soil, air, water and food is widely documented in literature and described herein. These additives can potentially migrate and undesirably lead to human exposure via e.g. food contact materials, such as packaging. They can, also, be released from plastics during the various recycling and recovery processes and from the products produced from recyclates. Thus, sound recycling has to be performed in such a way as to ensure that emission of substances of high concern and contamination of recycled products is avoided, ensuring environmental and human health protection, at all times.

Fully integrated modelling for sustainability assessment of resource recovery from waste

This paper presents an integrated modelling approach for value assessments, focusing on resource recovery from waste. The method tracks and forecasts a range of values across environmental, social, economic and technical domains by attaching these to material-flows, thus building upon and integrating unidimensional models such as material flow analysis (MFA) and lifecycle assessment (LCA). We argue that the usual classification of metrics into these separate domains is useful for interpreting the outputs of multidimensional assessments, but unnecessary for modelling. We thus suggest that multidimensional assessments can be better performed by integrating the calculation methods of unidimensional models rather than their outputs. To achieve this, we propose a new metric typology that forms the foundation of a multidimensional model. This enables dynamic simulations to be performed with material-flows (or values in any domain) driven by changes in value in other domains. We then apply the model in an illustrative case highlighting links between the UK coal-based electricity-production and concrete/cement industries, investigating potential impacts that may follow the increased use of low-carbon fuels (biomass and solid recovered fuels; SRF) in the former. We explore synergies and trade-offs in value across domains and regions, e.g. how changes in carbon emissions in one part of the system may affect mortality elsewhere. This highlights the advantages of recognising complex system dynamics and making high-level inferences of their effects, even when rigorous analysis is not possible. We also indicate how changes in social, environmental and economic 'values' can be understood as being driven by changes in the technical value of resources. Our work thus emphasises the advantages of building fully integrated models to inform conventional sustainability assessments, rather than applying hybrid approaches that integrate outputs from parallel models. The approach we present demonstrates that this is feasible and lays the foundations for such an integrated model.

Mining the physical infrastructure: Opportunities, barriers and interventions in promoting structural components reuse

Construction is the most resource intensive sector in the world. It consumes more than half of the total global resources; it is responsible for more than a third of the total global energy use and associated emissions; and generates the greatest and most voluminous waste stream globally. Reuse is considered to be a material and carbon saving practice highly recommended in the construction sector as it can address both waste and carbon emission regulatory targets. This practice offers the possibility to conserve resources through the reclamation of structural components and the carbon embedded in them, as well as opportunities for the development of new business models and the creation of environmental, economic, technical and social value. This paper focuses on the identification and analysis of existing interventions that can promote the reuse of construction components, and outlines the barriers and opportunities arising from this practice as depicted from the global literature. The main conclusions that derive from this study are that the combination of incentives that promote reuse of construction components and recycling of the rest of the construction materials with the provision of specialised education, skills and training would transform the way construction sector currently operates and create opportunities for new business development. Moreover, a typology system developed based on the properties and lifetime of construction components is required in order to provide transparency and guidance in the way construction components are used and reused, in order to make them readily available to designers and contractors. Smart technologies carry the potential to aid the development and uptake of this system by enabling efficient tracking, storage and archiving, while providing information relevant to the environmental and economic savings that can be regained, enabling also better decision-making during construction and deconstruction works. However, further research is required in order to investigate the opportunities and constraints of the use of these technologies.

Food waste co-digestion with sewage sludge--realising its potential in the UK

The application of anaerobic co-digestion of food waste with sewage sludge, although well established in many European countries, is still in its infancy in the UK. This process has many benefits to offer, with a successful application often associated with increased renewable energy potential, outweighing constraints associated with the variability of food waste and its handling requirements prior to co-digestion. With both regulations and water infrastructures designed and constructed on the basis of linear views and sectorial requirements and conditions and technologies from the past in many parts of the world, in the UK, sewage sludge and food waste digestion operations are also under very different regulatory and management regimes. With sustainability requiring that we do not address single issues in isolation, but through a systems approach that delivers integrated solutions, co-digestion of food waste with sewage sludge could become such a solution. If carefully applied, co-digestion can deliver beneficial synergies for the water industry and authorities responsible for food waste management. The collaboration of all relevant stakeholders and regulators to support changes to current regulatory frameworks to enable this, is proposed as the way forward, particularly as their complexity has been identified as the major hurdle to the implementation of co-digestion in the UK.

Food waste disposal units in UK households: the need for policy intervention

The EU Landfill Directive requires Member States to reduce the amount of biodegradable waste disposed of to landfill. This has been a key driver for the establishment of new waste management options, particularly in the UK, which in the past relied heavily on landfill for the disposal of municipal solid waste (MSW). MSW in the UK is managed by Local Authorities, some of which in a less conventional way have been encouraging the installation and use of household food waste disposal units (FWDs) as an option to divert food waste from landfill. This study aimed to evaluate the additional burden to water industry operations in the UK associated with this option, compared with the benefits and related savings from the subsequent reductions in MSW collection and disposal. A simple economic analysis was undertaken for different FWD uptake scenarios, using the Anglian Region as a case study. Results demonstrated that the significant savings from waste collection arising from a large-scale uptake of FWDs would outweigh the costs associated with the impacts to the water industry. However, in the case of a low uptake, such savings would not be enough to cover the increased costs associated with the wastewater provision. As a result, this study highlights the need for policy intervention in terms of regulating the use of FWDs, either promoting them as an alternative to landfill to increase savings from waste management, or banning them as a threat to wastewater operations to reduce potential costs to the water industry.

Occurrence and diurnal variation of polychlorinated biphenyls and polybrominated diphenyl ethers in the background atmosphere of Eastern Mediterranean

During a two-week intensive field campaign conducted at a background location of the Eastern Mediterranean, consecutive 10-h air samples were collected under intense photochemical conditions and analyzed for polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The average gas-phase concentration of total PCBs and PBDEs was 73+/-29 and 3.9+/-2.1 pg m(-3), respectively. The study of Clausius-Clapeyron plots and air mass back-trajectories assigned the origin of air masses as the factor largely controlling the variation of PCB and PBDE air concentrations in the study area. Using principal component analysis, discrete differences in PCBs homologue profiles were revealed between day and night samples and attributed to the daytime reaction with hydroxyl radicals. In contrast, PBDE homologue profiles did not show any characteristic day-to-night shifts that could be attributed to hydroxyl radical reaction or photolysis.