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Are Any Plastics Safe for the Environment?

Updated: Feb 12, 2021

Part 2 of our series on sustainability in care system, considers the plastics ecosystem and its alternatives. Not everything in the NHS can work with stainless steel or glass, nor maintain the same cost-effective safety as plastics. But polymer science shows us we can do better.

A question from a member of one of the UK's Academic Health Sciences Network sparked a debate about plastics. The fact the question was asked, made us realise we needed to simplify yet another complex concept even more.

"The NHS are trying to cut down on plastics. Moving to reusable items and using materials like stainless steel, card and glass. But 3D printing uses plastics. Is this really a good idea?"

This is a very good question, but the answer isn't straightforward as there are several things to consider systemically.

The NHS will also work to substitute for low-carbon alternatives where they are available. New technologies and innovations are developing at an incredibly fast pace. Our role is to identify and encourage innovative approaches that will deliver improved patient outcomes with a reduced impact on the climate. For example, we anticipate that bio-based polymers will produce significant savings of 498 ktCO2e in the future.

-- NHS Towards Net Zero, 1st October 2020

Not All Plastics are created equal

The first problem to consider is which types of plastic are we discussing?

Most crude oil based polymers like Polystyrene deservedly earned a bad name because they can't be recycled. Most plastics weren't but as time went on, we have developed a better understanding of plastic recycling and now have mechanical and biochemical ways to recycle various forms of plastic. Yet, the vast majority are still made out of crude oil.

In part 1's post, we examined the climate impact of health plastics from a number of sources. Whether extraction, manufacturing, packaging, logistics, use and recycling or disposal. Each kg of plastics and the work associated with them, aggregates all these processing steps into a proxy of "1kg of work". In the NHS's case, the footprint of 1kg of work, for 1kg plastics is over 4.7kg.

Disposing of non-recyclable plastics means that 1kg of work disappears altogether. So to provide another 1kg of plastic items, a new 4.7kg footprint has to be consumed, when accounting for all associated energy and transportation.

PETE, HDPE, V, LDPE, PP, PS, Other plastics
7 types of plastics. Some of which are recyclable, but many local authorities do not. Check your local area

Recyclable plastics on the other hand, eradicate the extraction & processing of another 4kg of oil and expending some of the savings to transport and recycle it (9% of it to be exact). Meaning the second 1kg of plastics only has a footprint of 410g, compared to the initial 4.7kg footprint of unrecycled plastics. Saving a share of 4.29kg.

However, it still has a "first kg" footprint of 4.7kg. Meaning it's still as bad for disposable items, because it is the same climate cost between the two until a second cycle recycles it.

One way to solve this uses starch based polymers like Polylactic Acid (the crystallised form is better known as "Vegware"). Made from fermented starch, like corn or sugarcane pulp, they do not use any crude oil at all. However, they are not without their mishaps!

Vegware was released into the consumer market and it wasn't long before systemic holes were identified in its climate-case. Especially around processing.

- They could not be disposed of in landfill, as they release methane while decomposing

- They required industrial composting facilities. Residential compost heaps weren't enough. Some plastics didn't compost at all in 2 years

- Differences between local authority policies, meant some required them to be deposited in general waste, which makes its way to landfill :(

- Plastics with food deposits were rarely recyclable and had to be placed in general waste

- They do not break down to nothing. They can become microplastics, which in turn make their way into the food chain

There were also concerns about using crop space to grow oil substitute starch for plastics. The UN and European Union independently found this applied in under 1.5% of cases as most of the plastics were made from crop-waste.

Despite this, all is not lost! As well as being [semi-]compostable, it's also fully recyclable. Yielding 1kg of plastic from 1.6kg of corn starch, even without the fact it's sustainable, is still better than extracting and cracking 4kg of crude oil. This is something we know well, because we have recycled it!

PLA recycling is also low temperature. It doesn't need the huge amounts of energy to process. Source to recycling also happens in just a year, compared to millions of years of fossil decomposition for oil-based plastics. We are unlikely to run out of this material and recycling it is much kinder to the environment. Recycling and manufacturing on-site, is even better still.

Strong and Light

Glass and stainless steel are two materials used widely in the health service. Glass syringes were used as late as the 1970s, before being replaced by transparent plastics. Stainless steel is ubiquitous in implants and surgical tools.

Yet, not everything can be made out of those two materials. Both inflexibility and heavy, and less unsuitable for mobile patients or during venipuncture. Pressing a glass butterfly cannula risks breaking the thin brace and causing injury. Stainless steel is just too heavy to stay in place.

Then there is the problem of cleansing & sterilisation. Water does not take zero energy to heat to sterile temperatures in ultrasonic baths or sterilisers. However, you must not just dispose of it in general waste! Leading to the problem of how to collect and/or segregate such plastics.

Consider Systemic Effects

Climate issues must be considered in the round. What is taken off plastic disposal, may be offset with greater climate impact up or down stream. Without an end-to-end lifecycle view of crude oil based plastic replacement, we risk simply changing the problem.

Current NHS manufacturing-delivery-use-disposal cycle of plastics
Where does all the carbon go? Current NHS manufacturing-delivery-use-disposal cycle of plastics

Ultrasonic baths clean medical equipment using a 6kW ultrasonic source and heated water bath. Equipment is places in the bath via a conveyor, is bathed for 20 to 60 minutes.

The total average power consumption is 8kW per item, 6 of which may or may not come from renewable source. A figure that is 11x higher than an Automedi manufacture-recycle cycle and consequently, 11x more expensive to run. In this case, using recyclable bioplastics is better for both the climate and the public purse because heating and electricity consumption offset savings from reusable glass or stainless steel.

Plastic Fantastic?

As UK society and the NHS gets used to working with novel polymers and aims to change its consumption of oil to cut down on it's extremely large footprint, it naturally creates threats to incumbent suppliers. Many of whom rile against the idea they may have to recertify their products. Yet, they would have to anyway, if they moved to glass or stainless steel options, where they are appropriate and because they are not always appropriate, plastic in their newer, climate friendly forms, have a longer life in the future.

With the climate impacts understood, the question is one of communication. Given they behave so differently, is there value in in ceasing to call them plastics?

What do you think?

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