A lead on recycling PVC
The end-goal of sustainability is progression from today’s less than ideal norms to achieve a ‘perfect’ situation of no toxic or accumulative substances, depletion of ecosystems or infringements upon human rights. This systemic summation is neatly defined on a scientific basis by The Natural Step (TNS), an international NGO, through its principles of sustainability otherwise known as the four ‘System Conditions’.
No-one is likely to argue against this ultimate, and ultimately necessary, ideal of sustainability. However, questions arise about its attainability in the immediate or near term. Whether we are talking about sustainable food, transport, urban infrastructure, clothing, flood management, energy or other societal systems, we start from where we are now and, by vast majority, that is significantly distant from the ideal of sustainability. Sustainable development is the journey from where we are now, ‘good’ incremental steps leading progressively towards the ultimate and ‘perfect’ goal of full compliance with principles of sustainability.
The TNS approach tackles this journey pragmatically through a series of tools. The process starts with sustainability awareness – the TNS science model and its four linked System Conditions of sustainability, visioning how a process or product might ultimately be fully sustainable and assessing current reality against those System Conditions, and then ‘backcasting’ incremental, attainable steps leading towards the ideal goal.
The backcasting approach ensures that identified strategies build towards a final goal of sustainability, rather than reacting to current problems through measures that may serve only to lock investment into a blind alley. Backcasting also addresses the harsh reality that the starting point is generally very distant from being sustainable. This approach reflects that all incremental steps must be financially sustainable. After all, a company or other institution that goes bust due to over-reaching to achieve bold aspirations is no great model of, nor contributor to, sustainability!
This brings us to the relevance of French writer and philosopher Voltaire’s observation that ‘Perfection is the enemy of the good’ to material management conflicts in Europe and its strong resonance with contemporary sustainable development challenges.
Expectations of immediate attainment of the ultimate ‘perfect’ outcome may be practically infeasible. However, sequential and feasible ‘good’ steps can be made, informed by backcasting as stepwise progression towards the eventual, if practically aspirational, goal of full sustainability.
This conflict is manifest in two European Commission strategies – Towards a non- toxic environment strategy and Circular Economy – Implementation of the Circular Economy Action Plan. Notwithstanding their significant influence on thinking about the use of chemicals across Europe, there are inherent tensions between them in terms of resource recovery and the re-entry of ‘problem’ constituents of end-of-life products entering recycling streams.
Take, as a topical example, lead stabilisers in PVC (polyvinyl chloride) products. PVC has many virtues in terms of its lightness, low cost, adaptability and durability, meaning that many PVC applications deliver long service lives per unit of chemical material with little or no maintenance inputs and potential for recyclability at end-of-life. As PVC polymer chains are prone to thermal oxidation, it is necessary to add heat stabilisers to products made from virgin PVC. Historically in Europe, lead was a constituent of one such family of stabilisers. However, lead-based additives to virgin PVC have, since before the end of 2015, been substituted with other thermal stabiliser substances across Europe, one of a range of significant and tangible outcomes of Europe-wide voluntary commitments to make audited progress towards sustainability under the VinylPlus programme.
VinylPlus comprises players in the PVC industry and value chain signing up to five interconnected Sustainability Challenges, illustrated above. These include ‘Sustainable use of additives’ under which the voluntary lead phase-out was coordinated, as there is no disagreement with the need to phase out lead as has already been achieved in short-life applications such as a road fuel, toys and paint additives, as well as in plumbing, where there is greater risk of human contact and consequent health impacts.
‘Controlled loop management’, addresses ‘…work towards the more efficient use and control of PVC throughout its life cycle’ encompassing the whole societal value chain, tangible voluntary progress towards which means that, as of 2019, close to 800,000 tonnes – roughly one-third of the PVC waste generated in Europe – is now recycled.
For both European Commission and TNS initiatives, circular use of resources means material and value recovery from end-of-life products. Given the longevity of many PVC products, this inevitably means that lead stabilisers within older formulations will be part of the flow of materials entering recycling streams. Lead is not the only additive substance in PVC products that may be regarded as problematic in legislation and PVC is far from alone in this regard as many end-of-life materials may contain substances now, or potentially in future, regarded as of concern, such as wood preservatives, contaminants and coatings in metals, additives to other polymers, or flame retardants and other constituents of alternative materials. Furthermore, as greater knowledge of chemical impacts become known, more substances assumed ‘safe’ today are likely over time become subject to closer scrutiny and concern.
Taking a purist view of the European Commission’s Towards a non-toxic environment strategy – seeking perfection immediately as Voltaire warned – then the good incremental steps of moving towards the EC’s Circular Economy – Implementation of the Circular Economy Action Plan and the VinylPlus ‘controlled loop’ can never be attained if there is the slightest risk of end-of-life materials containing legacy materials entering recycling routes. Bear in mind that new legacy constituents, of other materials as well as PVC, are likely to be identified through continuously growing knowledge and increasingly subtle chemical evaluations.
This begs questions as to whether it is the intent of the ‘non-toxic environment’ strategy to condemn us to a pathway of the kinds of linear resource use strategies that underly many of our sustainability challenges, including the generation of toxins post-disposal. If we create institutional obstacles to material and value recovery of end-of-life substances, we can only perpetuate the problems of deepening resource scarcity, ethical issues along the supply chains of some virgin materials, wastage of material value, and reliance on disposal systems such as landfill and incineration with associated pollution. This range of dystopian outcomes is hardly a model of a ‘non-toxic environment’, with many adverse sustainability outcomes that are surely inconsistent with the ultimate intent of a non-toxic environment strategy.
Immediate demands for the ‘perfection’ of zero potentially problematic constituents in a less than perfect world create a barrier to ‘good’ steps collectively comprising a scientifically informed pathway leading incrementally towards sustainability.
Is absolute rejection of any use of lead-containing end-of-life materials, even when that lead is firmly immobilised – embedded into the recyclate and unable to leach out – really contributing to sustainable development? For all its idealism, if it locks us into the kinds of linear use and disposal habits that generate resource wastage, environmental and ethical problems, it erects irreconcilable barriers to ‘real world’ progress towards sustainability.
Objectively, within the less than idealistic world we inhabit, it would be madness to demand that all remanufactured PVC should contain zero additives which, though formerly acceptable, are now deemed inappropriate in virgin production. This would further condemn much, or all, of the vast mass of PVC material currently serving a diversity of beneficial uses to ending its life in unmaintainable landfill sites or incinerators, or export outside the EU. Such demands would certainly kill pretty much all initiatives and investments in recycling infrastructure, and therefore practical progress towards circularity – hardly a great leap forward on the sustainable development journey!
Also, let’s remind ourselves, lead is just one amongst very many potential contaminants in wide circulation in the world, and not just in PVC but in many of the materials in common use.
Towards a cleaner world
Let’s take a more rational view, based on the desirability, but also the necessarily long-term achievement, of full sustainability. Owing to the adaptable and durable properties of PVC plastics, very large volumes of PVC materials are in use in long-life applications such as building products, pipes, cable, flooring and countless other uses. Material and value recovered from end-of-life PVC-containing products makes a significant contribution to sustainable development relative to both virgin production and disposal. It creates recyclate with a substantially lower carbon footprint, also making far lesser demands on supply chains and disposal infrastructure.
From a systems perspective, what is the fate and sustainability consequence of the estimated 150-200 million tonnes of PVC in beneficial, long-life uses across Europe if we don’t allow it be recycled?
It is theoretically possible to segregate recyclate containing a proportion of legacy lead or other substances. There are 10-year studies, performed by third party scientific bodies, that have proven the lack of bioavailability of legacy lead content of PVC waste. On the basis of these studies, ECHA, SEAC and the EU Commission drafted the amendment to the Regulation (EC) No 1907/2006 Restriction Proposal . Research into technical solutions for extracting legacy additives from recyclate could also accelerate progress towards cleaner chemistry. In the meantime, there is no shortage of safe uses of recycled PVC potentially containing a proportion of lead, for which such materials are already widely used.
Were this more rational path to be followed, building in stepwise progression to the sustainable end-goal, increasingly pure flows of recyclate would result over time as more end-of-life PVC produced under a clean chemistry strategy enters the circular economy. This represents a glide path towards incrementally cleaner recycled product, with the potential for further blending with virgin and recovered sources to reduce legacy content further for specific applications.
This strategy would assure simultaneous, stepwise progress towards the longer-term goals of both currently conflicting EC strategies by building in recognition that full compliance will take time. Importantly, it would offer assurance for those investing in the recycling infrastructure essential to address sustainable development challenges. Also there is the likelihood of more legacy constituents coming to light not just in PVC but also in a range of other substances.
Which other better solutions could we envision for a heavy metal such as lead, which is already present in the Earth’s crust? Metals cannot practically be eliminated or transformed into anything else – the best that a responsible society can do is to avoid its accumulation in natural systems – by contrast, landfill, incineration and export are processes most likely to promote the release of lead into ecosystems in far less controlled ways. Mechanical recycling represents the best possible solution to keep lead in a ‘safe grave’, while in the meantime providing tangible benefits to society and saving energy and raw materials.
Bigger picture, longer term
Importantly, this point applies not just to historic lead additives, nor just PVC, but to all other substances in widespread use. This includes the large volumes of products imported from regions not observing the same controls as in Europe, for which more stringent controls on import and use are undoubtedly required.
The simple question that policy-makers and influencers must answer is whether or not sustainability is the intended end-goal. Either this is achieved on a progressive journey or is thwarted by continuing accumulation of waste rejected by an instantaneous and inflexible leap to chemical purity – unjustified both scientifically and economically – with associated wastage of value and material.
We can, in short, not afford to let an instantaneous expectation of and leap towards ‘perfection’ prevent us from innovating and taking ‘good’, rationally science-based and profitable steps that progressively lead towards a sustainable future.
This link to the work of Voltaire was first explored in Stepping towards sustainability. Everard, M. (2014). Materials World, December 2014, pp.27-29.