Microplastics pollution poses significant problems for drinking water

With the proliferation of microplastics pollution posing significant concerns for environmental and public health, Eurofins is participating in an international intercalibration study for determining microplastics in environmental samples.

The Southern California Coastal Water Research Project (SCCWRP) involves 40 laboratories across six countries, tasked with measuring micro- and nanoplastic in water samples, with the aim of developing a standardised approach to identifying plastic particles more effectively.

Eurofins Regional Technical Manager Dr Bob Symons said the understanding of microplastics pollution measurement, as well as toxicology, is a fast-growing field, but there is more work to be done in terms of assessing the most effective way of measuring the problem.

“There has been a lot of public pressure on reducing plastic pollution, particularly single-use plastic. But, most of this visible pollution is what we call macroplastics. Those macroplastics will break down to microplastics, but at the moment there is not a lot of toxicological information on the harm these can do,” he said.

“And microplastics are everywhere. When we wash our clothes, they shed fibres, and a lot of those fibres are synthetic, such as polyethylene terephthalate (PET). Eventually, those microplastics find their way into the sewage treatment plants and ultimately into the environment.

“Most of the microplastics do not break down in the wastewater treatment process. They are concentrated into biosolids, which then get applied to agricultural land, creating a loop where microplastics pollution gets back into the food chain.”

Symons said that while research in the field of microplastics is expanding quickly, there’s a need to develop more robust analytical techniques in terms of measurement.

“There is some recent research, and that research and literature is growing very rapidly. Eurofins wants to be at the forefront of this issue. We’ve been supporting clients in the water sector around this issue by developing an analytical technique utilising state-of-the-art technology” he said.

New technology to measure microplastics pollution

In terms of analysing microplastics, Symons said being able to identify the size and form of microplastics is crucial to assessing their impact, which has led to the take up of innovative technologies in sample assessment, including new infra-red imaging systems.

“Infra-red is quite a mature technology, it’s been around for quite some time. It’s very good at identifying polymers, but the disadvantage is that it is very slow. It can take 8 to 10 hours to do a data acquisition, and for a commercial lab, this is far too long,” he said.

“With laser direct infra-red (LDIR), we found it could perform the same task as traditional IR techniques but in a fraction of the time. We took that technology on board, but there is quite a lot of work involved in preparing complex samples, like sewage or wastewater, or samples with lots of organics.”

Symons said that alongside Eurofins' development of LDIR technology and processes, a broader conversation around how to define microplastics has been developing, too.

“Generally, microplastics were considered to be one micron and up to 5 mm. But there are also nanoplastics, which are sub-micron. Some research is being directed to these smaller sized plastics, because the smaller the size, the more impact it’s going to have on cells in the body,” he said.

“If you can’t measure it, then you can’t define if there is a problem. Size is really important.”

Symons said Eurofins’ LDIR technique has proven effective in measuring microplastic size, but also identifying the type of polymer present in the water sample.

“Our technique can look at 20 microns up to 5 mm and we can identify the major polymers. We also look at morphology, too – whether the microplastic is a fibre, fragment, film, foam or a sphere.”

Furthermore, the method has been developed and validated to measure microplastics in bottled water, drinking water, surface and groundwater, biosolids, marine sediments, molluscs, fish and air.

Methodologies to study microplastics in water

The Southern California Coastal Water Research Project (SCCWRP) has been the first organisation to start putting together any sort of guidelines or legislature around microplastics, Symons said, which instigated the collaborative project.

“SCCWRP’s idea was to run a program, in collaboration with a range of global laboratories using different techniques,” he said.

“The participating labs are using either Fourier transform infra-red (FTIR), or laser direct, or another infra-red technique called Raman, which can look at smaller microplastics.

“The aim has been to standardise the methodology and come up with some techniques. There is currently no set analytical procedure for measuring microplastics. There are a range of techniques being used, but we don’t have a standard procedure for measurement.”

Symons said California is very much like Australia, in terms of water scarcity issues, and there’s a need for more information around microplastics in the wake of conversations around recycled water and aquifer recharge.

“California is very water conscious, and they have quite a big push for recycled water, just like Australia. From a litigation point of view, they want to make sure that the water they put back into aquifers, water that’s being recycled, is as clean as possible,” he said.

Symons said the results from the international collaboration will be ready in September 2021.

“The upshot is that SCCWRP will look at all the different techniques used. The preliminary data suggests the laser direct infra-red techniques will likely prove most valuable, as they look at size, identity and morphology,” he said.

“The other techniques only really provide an amount of plastic, without being able to categorise. SCCWRP will come out with some standard operating procedures for analysing microplastics.”

This collaboration by forty labs across six countries will help standardise the identification of microplastics in water samples.