I work in a Biology lab, and we throw away a lot of plastics after using them just once. And if we do reuse them, it can involve an intensive cleaning process that rapidly wears out the quality of the plastic.
This is a common theme running through today’s bio labs, a theme large enough to have made mainstream headlines. Apparently the rest of the world doesn’t want to let us get away with producing AN ENTIRE 2% of the world’s plastic waste.
The problem is two-fold. Firstly, we’re using heaps of single-use plastics to avoid cross-contamination. Secondly, most recycling plants refuse lab plastics in case of health and safety risks. So we throw them into bright yellow biohazard bags instead and they go off to join the landfill.
So why do labs use so many single-use plastics, and what can they do to reduce it?
Need to avoid contamination? Want to save yourself a lot of time? The answer’s pretty simple, use everything once. There’s a far lower chance of contamination and you’ll avoid having to sterilise everything. If not for the environmental impacts, single-use plastics would seem to be a win-win situation.
For example, in my own lab, we often have to pipette transfer samples or pure DNA. That requires a pipette tip for every single sample, or we’d end up contaminating samples. We also can’t autoclave or sterilise these easily because they’re quite small and they’d end up having residue left inside. And if they’re used for animal samples or DNA, then they’re considered biohazard waste and can’t be recycled.
If they were used just for water or harmless reagents (chemicals), they can be recycled or composted, a strategy many labs are adopting. However, as noted by Nick Ciancio of the University of Alabama, this is not as easy as it sounds:
“If anything is improperly disposed of, it would be a pipette tip. The first time someone outside of the institution is contaminated with biohazardous material will be the last time we recycle lab material.”
Quite a significant problem, leading many labs to make the choice that pipette tips will be heading out with the trash, rather than the recycling.
The boxes that pipette tips come in are a different story. At first, the story seems to be getting worse not better … the plastic pipette tips come in plastic boxes. While this makes it very convenient to throw the box away, it is becoming increasingly common to buy tips by themselves in bulk to refill the boxes. Even better again, many pipette tip boxes come wrapped in plastic themselves (again, we’re being really sterile here), and we’re saving that extra plastic as well!
Great! We’re not using so much plastic. The down side is that filling boxes can be quite labour-intensive, which is certainly a cost that labs must consider.
Other types of tips (and plastic containers, plates and tubes found in labs) can be occasionally reused if contamination is not such a big issue. And certain items can be sterilised. Again, sterilisation is a labour-intensive process, often involving rinsing and washing (in our lab, soaking in RO water and bleach, just for starters) and then autoclaving. Some labs choose to do this to lower their plastic waste output and can streamline their processes so that it is more cost-effective to reuse than purchase new items and that’s great!
Unfortunately, sterilisation and washing does wear out the quality of the plastic. For many of the tip combs used in my own lab, we will only wash them 4 times before they become warped and damaged and no longer usable. Occasionally before reaching 4 washes they will already be warped and can be dropped from the machines, causing additional issues with contamination and purity of DNA. Similarly, we re-use our 96-well wash plates, but the heat of the autoclave often warps these as well and they stack up inside the rubbish bin. We have modified our processes to better maintain the quality of these plastics and it’s better than throwing them out after a single use, but we’re certainly not perfect.
Although I’ve written quite a bit about pipette tips, they are just an example. Labs are FULL of single-use plastics. To combat such overuse, scientists are increasingly looking at ways to combine experiments, use smaller containers, or switch to using glass that can be sterilised where possible. For example, combining multiple experiments or tests onto a single plate (again, only where this is possible). When pipetting a single reagent type, trying to do all the necessary pipetting with one set of tips.
There is so much to say on this topic. It’s vitally important, given the massive plastic garbage patch in the Pacific and increasing amount of plastics and microplastics contaminating our environment and killing species. Scientists of all people should be doing more to prevent this damage than anyone else. I hope this has at least given you some insight into why labs use single-use plastics and how they are trying to combat it!