Chemicals in the circular economy

August 27, 2015 at 5:41 pm | Posted in Feature Articles | 1 Comment
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Circular Economy Title Image

The “circular economy” is a generic term for a restorative industrial economy whereby economic activity conserves and increases resource rather than depleting it, via two circular systems of material flow: an ecosystem-integrated flow of biological materials, and a closed loop flow of technical materials (known as “nutrients” in much of the literature, in recognition of the biomimicry principles which inspired early circular economics).

Biological materials are designed to circulate safely in the biosphere, integrating with rather than degrading ecosystems, and are effectively ecologically reprocessed. Technical materials are those which are needed for human living (such as processed alloys and polymers) and cannot integrate with the biosphere without either degrading ecosystems (for example, if they are toxic) or becoming lost to the material economy (e.g. if steel is abandoned then it rusts, disintegrates and is distributed irretrievably into the natural environment). Technical materials are therefore circulated in a closed loop which is kept apart from the biosphere and reprocessed by the human economy.

The circular economy has its origins in 1970s rejections of linear “Take, Make, Dispose” industrial processes and consumer lifestyles, which deplete finite material reserves to create products that end up in landfills or in incinerators. Instead, “closed loop” material production processes were proposed. These go beyond simple increases in efficiency, understood as a reduction in fossil energy consumed per unit of manufacturing output, to a steady-state economy.

In a circular economy, the only virgin raw materials are renewable; otherwise, the sole feedstock of the economy is material which is already in use. This means all materials, rather than ending life as waste for disposal, are re-circulated in the economy as re-used and recycled materials. Waste is material loss and therefore resource leakage: the result is either economic contraction from less available resource or, if loss is made up by introduction of non-renewable virgin materials, the economy remains inexorably extractive. Since both are degradative, neither is sustainable nor ultimately a feature of a truly circular economy.

The transition to a circular economy presents many challenges. It variously requires: a move to a service- rather than a product-driven economy, to encourage systems and closed-loop thinking in product design; systems design to ensure services fit with the requirements of the system; economic diversification for resilience; the introduction of a labour- rather than capital-driven economy to enable re-engineering to replace primary material demand and to reduce the importance of the economies of scale which characterise the chemical and material industries; the extension of service life by ending use at obsolescence or loss of functionality rather than fashion; the taxation of resource use rather than labour; to name a few.

From the chemicals perspective, a major concern in the move to a circular economy is the risk of perpetuating exposure to and emission of hazardous chemicals by trapping problem substances in the technical material cycle, as recycling potentially moves them from a use whereby people are less exposed to one where they are more exposed. An example of how this can come to a head is where researchers have found brominated flame retardants (BFRs) in black plastics used in kitchen utensils (Samsonek & Puype, 2013). These BFRs have presumably been introduced via the plastic recycling process, as there would be no need for them in virgin monomers intended for this purpose, and they would be forbidden for use in articles intended for use in food preparation.

In fact, there are a number of problems which need to be addressed when it comes to considering how chemicals should be managed in the transition to a circular economy, including how:

  • Risk assessment is unlikely to have anticipated a high level of recycling. While risks may be managed in virgin materials and articles during first use (which is debatable in itself), when it comes to end of life and reincorporation into future goods, risks will be increasingly unpredictable and many substances in use now will pose unacceptable risks in the context of the circular economy. Chemicals will therefore pose environmental and health risks unanticipated by safety assessments which assume linear industrial processes.
  • Many articles in use now will contain products legal when first manufactured but illegal now, such as brominated flame retardants and heavy metals. New restrictions are continuously arriving and more will come in the future as understanding and acceptance of chemical risks changes (such as around endocrine disrupting chemicals). The less successful that decisions to use chemicals are in anticipating these changes, the more that legally unusable chemicals will contaminate the material economy, preventing material reuse and causing resource leakage.
  • It may not be clear whether a product contains restricted substances due to lack of clear information about the chemicals in products being discarded. Checking all discarded articles for levels of chemicals is not practical; if they used anyway, there is a risk that inappropriate chemicals may end up in the feedstock materials for e.g. children’s toys or food contact materials. This not only presents environmental and health risks but, if it results in low-value feedstock because the content cannot be trusted (or is not known), it also increases risk of resource leakage by inhibiting material recycling and undermining the move to a circular economy.

Much of this can be addressed by dealing with the familiar problems with chemical regulation, including: insufficient understanding of the toxicity of many chemicals which means substances which should be restricted are still in use; the slow pace of imposition of restrictions; the loopholes around chemicals in goods imported to the EU; and a lack of timely, accurate and accessible information about chemicals in products.

In terms of considerations specific to the circular economy, there needs to be an assumption of circularity in the safety assessment of chemicals, to include conservative assumptions about where material might end up given sub-optimal segregation during recycling and reprocessing. There also needs to be the assumption of 100% reuse, since a sustainable circular economy must minimise leakage and, where materials will escape the technical material cycle (as may happen in application of sewage sludge to farmland), must not degrade the environment. This suggests a hazard-oriented approach to restricting the use of chemicals, if risks become too difficult to calculate under assumptions of circularity. Companies should be anticipating the shift to a circular economy by substituting away from chemicals which are likely to be restricted in future, using anticipatory lists such as the SIN List.

To help users of recycled materials from introducing chemicals where they should not be used, there needs to be much better access to information about what is in any given article. Currently, there is only an obligation on manufacturers and retailers to declare, within 45 days of the information being requested, whether an article contains chemicals on the candidate list of Substances of Very High Concern. This is slow, bureaucratic and unreliable, as well as insufficient for recycling purposes. This system needs to be replaced with easy, immediate access to information at least about hazardous chemicals in products (potentially all chemicals, so users of recycled feedstock have full control of which chemicals end up where). This also means imports should be subjected to the same rules as products manufactured within the EU.

Finally, it needs to be accepted that currently not everything should be recycled: there needs to be a gateway on entry into the technical material cycle. So long as there are articles in use which contain hazardous substances, there needs to be serious consideration as to whether they should be introduced into the technical material cycle and incorporated into a circular economy, or if they should be excluded from it to prevent contamination of technical material inflow. Since circularity needs to be introduced with “clean” feedstock, it is likely to be better that a hazardous substance be carefully landfilled than end up in our living environment; the move to circularity can be stepped up as hazardous compounds are eliminated.

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