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Glass vs Plastic

I recently had a question about the eco footprint of plastic vs glassware.

What´s the best thing to use -- single-use plastic items or multi-use glass items?

That´s a really good question!

Cause even though most of us probably have a gut feeling that glass is way better than plastic in terms of ecological footprint, it isn't that simple:

Single-use plastic can actually be a better choice than glassware.

Wait a minute -- what?

The short explanation comes here:

On the one hand, the use of plastic disposables in the lab requires continuous production & shipping and it keeps producing waste.

On the other hand, glass items take more energy to produce, they are heavier to ship and they leave a much higher eco footprint while in use.

Let´s break it down a little bit and take a look at some of the relevant life phases:

PRODUCTION

It takes a lot of energy to produce glass items compared to plastic items. And glassware for labs takes even more energy to produce because it is made to resist high temperatures!

That means that you must use a glass item many more times than a disposable plastic item before the carbon footprint of the glass production is worth it. So if you´re not careful with your glass items and they break after not-so-many times of use, it's not worth it.

PACKAGING & SHIPPING

Disposable plastic items are continuously wrapped & shipped. On the other hand, glass items are heavier and thus give higher shipping emissions per item. When shipping/transportation runs on renewable energy sources, glass is without doubt the best option in terms of packaging and shipping!

THE USE

In most cases, the actual use of plastic in the labs doesn´t leave an eco footprint. In contrast, the use of glass items requires continous washing and possibly autoclaving. And autoclaving is a top offender when it comes to energy and water consumption in the lab!

You can reduce this part of the glass eco footprint by 1) autoclaving only when needed 2) always filling up the washing machine and the autoclave before running it 3) using eco settings if available.

WASTE

Glass can be recycled, so that´s a no-brainer, right? Well, not exactly. Unlike 'normal' glass, lab glassware isn´t recycled because it can resist really high temperatures. It must be heated up like crazy to melt -- and discarded/broken lab glassware therefore goes to landfills.

Plastic can be dealt with in different ways: Ideally, we sort the uncontaminated plastic and it becomes recycled. In reality, plastic is ridiculously difficult to sort because most plastic items don´t have pictograms or information telling us what kind of plastic it is. And even if we sort it correctly, the plastic will most likely end up in landfills or storage facilities, become incinerated or end in the environment.

If you dispose of your plastic as residual waste, the fate of the plastic is determined by your country or region: In Denmark and some other countries, we have a waste-to-energy system. We basically burn our waste and use the released heat for making electricity and for tele heating. Tele heating, or district heating, warms up our houses + the tap water in our houses. We clean the smoke that is released from burning the waste, so only CO2 and water is released from the process. In most other countries, such as in the US, uncontaminated lab waste (including plastic) goes to landfills. Contaminated laboratory plastic waste is combusted in medical incinerators and this process can emit various pollutants (metals, acid gases, cytotoxins etc) to the atmosphere.

The eco footprint of using plastic disposables thus depends on how your country or region deals with waste!

WHAT´S THE TAKE HOME MESSAGE?

In terms of environmental impact, glass isn´t necessarily a better choice than disposable plastic! Unfortunately, at this point, it´s not possible to say how many times you must reuse a glass item in order to make it worthwhile. This is mostly due to a lack of transparency in the glass/plastic production and because the eco footprint of glassware depends on your washing & autoclaving habits and how quickly you break your glass items.

The best tip I can give you is this:

It´s great if you can substitute plastic disposables for glass, but

  • do it for items that you use a lot

  • don´t buy more glass items than you need

  • be really careful not to break the glass

  • autoclave only when needed

  • always fill up the autoclave before running it

In an ideal future scenario, we use 100% renewable energy sources to fuel the production, the shipping and the autoclaving of glassware. And in the cases where glass won't do the job, we use plastic which is bio-based, fully recyclable and (truly) biodegradable!

Until then, 1) use glass when it makes sense for you and your lab mates 2) reuse plastic disposables whenever possible, and 3) get plastic products that contain less plastic.

I will get back to the latter tip in a future post!




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