Costas Velis - Profile on Academia.edu (original) (raw)

Papers by Costas Velis

Research Square (Research Square), Oct 22, 2023

Negotiations for a Global Treaty on plastic pollution 1 will shape policy on plastics production,... more Negotiations for a Global Treaty on plastic pollution 1 will shape policy on plastics production, use, and waste management for the coming decades. Parties will require a detailed baseline of waste ows and plastic emission sources at high resolution to enable identi cation of pollution hotspots and their causes 2 . Nationally aggregated waste management data can be distributed to smaller scale to identify generalised points of plastic accumulation and source phenomena [3][4][5][6][8] . However, it is challenging to use this type of spatial allocation to assess the conditions under which emissions take place . To this, we developed a novel methodology for a global macroplastic waste inventory; creating an explanatory framework that combines conceptual modelling of emission mechanisms with measurable activity data. Using machine learning and probabilistic material ow analysis we identify hotspots worldwide (50,072 municipalities) from ve land-based plastic waste emission sources. We estimate global plastic waste emissions at 52.5 million metric tonnes (Mt), of which 57% wt. are open burned. Highest contributions: India (9.7 Mt), Nigeria (3.5 Mt), and Indonesia (3.0 Mt). Uncollected waste is the dominant emissions source across Global South. This detailed evidence baseline can inform Treaty negotiations and help develop national and sub-national waste management action plans and source inventories.

Increasing aspirations to develop a circular economy for waste plastics will result in an expansi... more Increasing aspirations to develop a circular economy for waste plastics will result in an expansion of the global plastics reprocessing sector over the coming decades. Here we focus on two critical challenges within the value chain that as a result of such increased circularity may exacerbate existing issues for occupational and public health (1): Legacy contamination in secondary plastics, addressing the risk of materials and substances being inherited from the previous use and carried through into new products when the material enters its subsequent use phase; and challenge (2): Extrusion of secondary plastics in reprocessing, an end process of conventional mechanical recycling of plastics, involving heating secondary plastics under pressure until they melt and can be formed into new products. Via a systematic review (PRISMA guidelines, adapted), we considered over 4,000 sources of information, refined and consolidated into 20 relevant sources, which were critically assessed. We also derive prevalent risk scenarios of hazard-pathway-receptor combinations, subsequently being ranked. Our critical analysis highlights that despite stringent regulation, industrial diligence and enforcement, occasionally small amounts of potentially hazardous substances are able to pass through these safeguards and re-enter in the new product cycle. Although many are present at concentrations unlikely to pose a serious and imminent threat, their existence may be an indication of a wider or possibly increasing challenge of pollution dispersion, as the plastics reprocessing sector proliferates. But, in the Global South context, such controls may not be in place. Several studies showed emission control by passive ventilation, through open doors and windows followed by dilution and dispersion in the atmosphere, resulting in increased occupational exposure. It is recommended that further investigations are undertaken to establish the scale and magnitude of such phenomena, especially given the limited evidence base, with results informing improved future risk management protocols of a circular economy for plastics.

Plastic waste reprocessing for circular economy: A systematic scoping review of risks to occupational and public health from legacy substances and extrusion

Science of The Total Environment, Feb 1, 2023

ChemInform Abstract: Production and Quality Assurance of Solid Recovered Fuels Using Mechanical-Biological Treatment (MBT) of Waste: A Comprehensive Assessment

ChemInform, Aug 4, 2011

Review: 248 refs.

Across the Global South, electrical and electronic waste (e-waste) is recovered using rudimentary... more Across the Global South, electrical and electronic waste (e-waste) is recovered using rudimentary and often dangerous methods in informal and unregulated facilities. Although these activities provide a valuable contribution to the global circular economy, their uncontrolled nature results in a risk of potentially hazardous substance emission into the environment from where they may pose considerable risk to both occupational and public health. Here, we focus a systematic PRISMA review on two distinct groups of activities undertaken in e-waste management in low-and middle-income countries (LIMICs): (i) Physical deconstruction and reclamation, involving dismantling assemblies of items and materials to recover value; and, (ii) hydrometallurgical treatment, involving the dissolution and suspension of precious metals using solvents (cyanide) and acids (aqua regia). For comparison purposes, we consolidate information on (i) and (ii) according to the types of substances evidenced; and identify, critically assess and rank most prevalent hazard-pathwayreceptor (H-P-R) risk combinations experienced by people working across the Global South. Despite the proliferation of publications, evidence to assess risk is comparatively limited. Still, we are confident to highlight the extremely hazardous nature of work undertaken, often by children, handling highly hazardous substances without protective equipment to reclaim gold and other precious metals using hydrometallurgical processes. Emissions of hazardous substances, particularly potentially toxic elements (PTEs) from physical dismantling also represent a serious risk to health. Numerous sources speculatively link concentrations in the environment (a significant risk to children who have a tendency to eat soil) to e-waste dismantling processed. However, many of the sources that identify elevated substance concentrations in environmental media face difficulties in unambiguously and convincingly linking emissions from specific activities to the environmental concentrations, i.e. establishing causality. This key limitation presents us with a challenge for designing and implementing interventions to target, control and replace such highly risky resource recovery methods. Yet, such insufficient information cannot be used as an excuse for inaction, especially as our generalised H-P-R inferences here provide for sufficient interlinkages.

Despite the relatively benign material composition of construction and demolition waste (CDW), it... more Despite the relatively benign material composition of construction and demolition waste (CDW), its mismanagement can result in considerable harm to human health, not only for the 200 million workers in the sector but also for those who live and work in proximity to construction and demolition activities. The population and workforce in low-and middleincome countries (LIMICs) is most at risk, and therefore we have focussed the attention of a systematic review of evidence that associates CDW with negative health and safety outcomes in those countries. We used PRISMA adapted guidelines to review more than 3,000 publications, narrowed to 49 key sources that provide data on hazard generation, exposure and/or risk. Subsequently, hazard-pathway-receptor scenarios/combinations were formulated, enabling indicative ranking and comparison of the relative harm caused to different groups. Though the evidential basis is sparse, there is a strong indication that the combustible fraction of CDW is mismanaged and disposed of by open burning in many LIMICs, including increasing quantities of plastics used in the sector. It is likely that the off-cuts/residues of these materials will be burned; the high chlorides-content PVC represents a serious risk when combusted in open, uncontrolled fires due to the release of dioxins and related substances. A long-standing and well-known hazard, asbestos continues to represent a threat to construction and demolition workers throughout the world. Despite being banned in most countries, exposure to asbestos particles is thought to claim the lives of a quarter of a million people every year. Though much of this risk is concentrated in high income countries where it has been used over more than half century, it is anticipated that more than half of all deaths from asbestos in the coming decades will take place in India where many asbestos products are still on the market, without any sign of prohibition. Overall highest comparatively risks are concentrated in LIMICs where the majority of workers are informal and highly vulnerable to hazard exposure. Combined with the sheer quantities of CDW, the risks can anticipated to persisturgent attention to risk mitigation and control is needed.

The critical functionality provided by the informal e-waste recycling sector to the global circul... more The critical functionality provided by the informal e-waste recycling sector to the global circular economy is marred by the hazardous emissions from this practice when it is carried out under informal and unregulated conditions in the Global South. Here, we focus a systematic review (PRISMA) of evidence specifically on rudimentary thermal processing activities that are carried out to disassemble and recover metals bonded into the complex assemblies and composites of electrical and electronic products and items. We identified main combinations of hazard-pathway-receptor (H-P-R) associated with exposure to risk and ranked them to indicate severity and prioritise research needs and interventions. Two practices, open burning and heating/melting/roasting are highly efficient in comparison to mechanical disassembly of many components and materials, presenting a challenge for actors who want to discourage them. Yet, these activities result in significant and very serious potential health effects as evidenced by 48 references screened and critically assessed. Though a large body of research exists that report observations of potentially hazardous substances in environmental media and human bodies, there is an abject paucity of reliable or even indicative data to indicate the scale of the e-waste processing activity. Moreover, the concentrations measured in almost all studies suffer from a multiplicity of confounding activities, creating challenges regarding identifying the activity source. System level interventions should be designed to effectively mitigate the risk, whilst rapidly transitioning to low-risk processing with effective pollution abatement in place and safe systems of work.

Waste Management & Research, Dec 29, 2021

The time has come for a treaty on plastic This anticipated development would be building upon all... more The time has come for a treaty on plastic This anticipated development would be building upon all the previous United Nations Environment Assembly (UNEA) resolutions: we had one in each of the five meetings that preceded the forthcoming UNEA 5.2. There seems to a wide consensus that towards a treaty is what is needed. The idea has been actively promoted by non-governmental organisations (NGOs) and lobbying stakeholders, not least from Norway, who have released over the last 2 years related reports exploring the need for such an agreement; and supported by major players in the sectors involved, such as the International Solid Waste Association (ISWA), through its Task Force on Marine Litter. However, the very nature of such an agreement, its scope and level of ambition are still to be seen. A resolution proposal has already landed in the public domain, enjoying the support of multiple governments.

UNEP eBooks, Sep 6, 2015

Chapter 3 provides a context or setting to the GWMO by presenting data as an evidence base regard... more Chapter 3 provides a context or setting to the GWMO by presenting data as an evidence base regarding waste generation and its management across the world. The Chapter starts by looking at the relative quantities of different types of wastes from various sources (Section 3.2). The focus then turns to municipal solid waste (MSW) where data on quantities and composition as well as past trends and future projections are presented (Section 3.3). Section 3.4 overviews the status of MSW management across income groups and regions. It focuses first on the protection of public health by ensuring that all wastes are collected, and then on environmental protection by phasing out uncontrolled disposal and open burning of waste. The later sections focus on resource recovery (Section 3.5), looking at collection for recycling, the importance of source segregation, and available technologies for resource recovery. This is followed by an examination of the global industry in secondary materials (Section 3.6). The chapter is followed by a series of Topic Sheets focusing on waste streams of particular interest, including construction and demolition waste, hazardous waste, e-waste, plastic waste and marine litter, disaster waste and food waste.

Enabling the informal recycling sector to prevent plastic pollution and deliver an inclusive circular economy

Environmental Science & Policy, Dec 1, 2022

United Nations’ plastic pollution treaty pathway puts waste and resources management sector at the centre of massive change

Waste Management & Research, Apr 18, 2022

Scaling up resource recovery of plastics in the emergent circular economy to prevent plastic pollution: Assessment of risks to health and safety in the Global South

Waste Management & Research, Jul 23, 2022

Over the coming decades, a large additional mass of plastic waste will become available for recyc... more Over the coming decades, a large additional mass of plastic waste will become available for recycling, as efforts increase to reduce plastic pollution and facilitate a circular economy. New infrastructure will need to be developed, yet the processes and systems chosen should not result in adverse effects on human health and the environment. Here, we present a rapid review and critical semi-quantitative assessment of the potential risks posed by eight approaches to recovering value during the resource recovery phase from post-consumer plastic packaging waste collected and separated with the purported intention of recycling. The focus is on the Global South, where there are more chances that high risk processes could be run below standards of safe operation. Results indicate that under non-idealised operational conditions, mechanical reprocessing is the least impactful on the environment and therefore most appropriate for implementation in developing countries. Processes known as ‘chemical recycling’ are hard to assess due to lack of real-world process data. Given their lack of maturity and potential for risk to human health and the environment (handling of potentially hazardous substances under pressure and heat), it is unlikely they will make a useful addition to the circular economy in the Global South in the near future. Inevitably, increasing circular economy activity will require expansion towards targeting flexible, multi-material and multilayer products, for which mechanical recycling has well-established limitations. Our comparative risk overview indicates major barriers to changing resource recovery mode from the already dominant mechanical recycling mode towards other nascent or energetic recovery approaches.

Advancing plastic pollution hotspotting at the subnational level: Brazil as a case study in the Global South

Marine Pollution Bulletin

ESCAP, 2021

Promoting these very important results, the Department of Natural Resources and Environment of Da... more Promoting these very important results, the Department of Natural Resources and Environment of Da Nang City will continue to make efforts and coordinate with national and international organizations to effectively mobilize the participation of all organizations and communities. The people of the city aim to minimize the amount of plastic waste, contributing to the construction of an Environmental City!

Waste to Wealth: Can improving solid waste management in emerging countries reduce poverty, create employment opportunities and address development goals?

Historically, bilateral donors and multi-lateral development banks have provided relatively limit... more Historically, bilateral donors and multi-lateral development banks have provided relatively limited attention and funding to solid waste management issues in a development context. However, this situation is changing with there being a growing consensus that improving solid waste management conditions can address a wide range of development issues (for example, addressing the health impacts associated with open dumping of wastes and reducing flooding risks, as well as generating important benefits in the form of livelihoods and resource conservation, and serving as a proxy for good governance). This paper considers the achievements of Living Earth Foundation’s Waste to Wealth programme, funded by the UK’s Department for International Development (DFID), the European Union and Comic Relief. The programme, which operated from 2010 to 2015, was targeted at improving solid waste management and creating livelihood opportunities in urban slum areas in Uganda, Nigeria, Cameroon, Sierra Leo...

Complex-value optimisation of power plant systems co-firing coal with biomass and SRF

Interventions that focus on protecting the environment and human health, have started to be incor... more Interventions that focus on protecting the environment and human health, have started to be incorporated in various sectors. One such intervention is the co-firing of biomass and SRF with coal in power plants. While this intervention contributes positively to reducing carbon emissions and other pollutants from the extraction and burning of fossil fuel, it may also result in a number of hidden aspects, the evaluation of which is important. In order to provide the basis for such evaluations the technical aspects that govern the basic premises of such interventions have to be clarified. In the case of biomass and Solid Recovered Fuel (SRF) co-firing with coal, the physical and chemical properties of the fuels and the technical implications that these may have on the process performance and the produced by-products, are of significant importance. This is because technical interventions may result in implications in the environmental, economic and social domains of value, indicating the ...

Large quantities of mismanaged plastic waste threaten the health and wellbeing of billions worldw... more Large quantities of mismanaged plastic waste threaten the health and wellbeing of billions worldwide, particularly in low- and middle-income countries where waste management capacity is being outstripped by increasing levels of consumption and plastic waste generation. One of the main self-management strategies adopted by 2 billion people who have no waste collection service, is to burn their discarded plastic in open, uncontrolled fires. While this strategy provides many benefits, including mass and volume reduction, it also results in the release of chemical substances and particles that may pose serious risks to public health and the environment. We followed PRISMA guidelines to select and review 20 publications that provide evidence on potential harm to human health from open burning plastic waste, arranging evidence into eight groups of substance emissions: brominated flame retardants; phthalates; potentially toxic elements; dioxins and related compounds; bisphenol A; particula...