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Plastics: a macro or micro problem?

Plastic as a problem is no longer a new phenomenon with ever-growing focus and concern on the volume of plastic in the environment. According to Greenpeace, 12.7 million tonnes of plastic make their way to the oceans each year threatening the marine ecosystem.

Scenes of marine wildlife entangled in plastic or plastic pollution on beaches are hitting media headlines but the extent of the problem has reached a point of – quite literally - unseen proportions. Microplastics are a result of large plastic items (macroplastics) degrading down to tiny fragments of the original plastic product, and are becoming an increasing environmental concern.

Paul Walker, SOCOTEC’s technical and development specialist, discusses microplastic analysis and its importance to understanding how widespread plastic is in our marine environment.

What are microplastics?

Less than 5mm in diameter, microplastics are fragments or particles of plastics from macroplastic sources that have reduced in size. Plastic carrier bags, bottles, packaging, straws are just a few examples of plastic sources that can reduce down to microplastic particles, as well as microfibres from synthetic clothing. Microbeads, an intentionally created microplastic for the benefit of the cosmetic industry, are also adding to the plastic pollution of the marine environment.

Although anything less than 5mm is classified as microplastic, there is no definitive minimum size before it is classified as a nanoplastic. Nanoplastics are plastic fragments thousands of times smaller than microplastics that could have an effect on organisms through absorption into the body and pass through into cells.  Once inside the cell, the nanoplastic has the potential to cause physical damage from either the fragment structure itself, or from the chemicals that could be absorbed within the nanoparticle. Research into the health effects of nanoplastics is ongoing with more needed to be done before definitive health effects can be associated.

Microplastics in marine wildlife

Measures and initiatives are being put into place to limit the amounts of single-use plastic being consumed, although the problems are already beyond extensive.

Research conducted by the University of Hull has identified that microplastics – as a result of plastic degradation – is impacting on the food chain. Mussels sampled from around the UK coast, as well as UK supermarkets, were found to contain microplastics in 100% of the samples taken. With the University of Plymouth’s study on the uptake of plastics within scallops reaching similar result, it is no surprise that microplastics – and nanoplastics - are having significant effects on the marine environment.

Piloting change

The increase of microplastics in the environment can only be assumed, correlating with the 12.7 million tonnes of plastics arriving in our oceans. Although in its infancy, projects are beginning to pilot change across the UK to mark the way for improvement.

plastics in the waterways (CRT image)

The Canal & River Trust (CRT) has been undertaking a project to investigate the litter and plastic problem within the UK’s canals and rivers. In addition to gathering data on the amount and types of litter collected at various locations, CRT called upon SOCOTEC to provide microplastic analysis on sediment samples to analyse the extent of the problem.

 

 

Of the fifteen samples taken from canals and rivers, SOCOTEC has discovered that 100% of samples contained microplastics. SOCOTEC’s final report incorporated the total number and physical type of particles present.  Samples came from a range of both industrial and rural sites with microplastic contamination, ranging from a few hundred particles per kg to hundreds of thousands. The information will support The Trust in their awareness campaigns; collecting and publicising data on the scale of the plastic problem in the UK waterways aims to urge communities and policy makers to help tackle this global problem.

Additionally, Royal HaskoningDHV and SOCOTEC have jointly undertaken a pilot study in Northeast England, with SOCOTEC analysing the presence of microplastics within sediments taken from the sea bed to quantify microplastic concentration.

With 24 sea bed sediment samples collected off the North East coast, SOCOTEC analysed the samples for plastic particles between 300 microns and 5 mm in size with results revealing the presence of microplastics within all 24 samples. The most common microplastic type was microfibres, accounting for 54% of the microplastic particles found and all samples contained microfibres.  Microfragments accounted for 41% of microplastics and were present in all but one sample.  Microbeads were the least common microplastic type (accounting for the remaining 5%) and were present in only 10 of the 24 samples.

Full details of the study can be found in RoyalHaskoningDHV’s report.

Developing standards and methodologies

I recently attended the microplastics analysis workshop and first worldwide inter-laboratory study at the Vrije Universiteit in Amsterdam, where over 110 experts in the analytical community gathered to review analytical issues surrounding microplastic analysis.  It was extremely positive to see so many of the analytical community collaboratively working to develop the microplastic analysis methodology to achieve quality, reliability and consistency across the data being produced. 

microplastic analysis under the microscope SOCOTEC

As one of the first UK laboratories to provide microplastic analysis as a commercial service, our specialist chemistry laboratory can help determine the extent of the problem. It’s a lengthy process – to accurately isolate microplastics from all other content including: sand, glass, stone as well as other inorganic and organic particles - but crucial to calculate the number, physical type and weight of the microplastics present. 

 

In addition, SOCOTEC’s infrared microscope equipment can identify the polymer type of plastic, important in positively identifying a microplastic and helps in identifying the source of the material.

Supporting change

Microplastic analysis is one of the first steps to understanding the extent of the problem and informing change in environmental legislation and control. With a driving need to reduce plastic in the oceans and many pushing for sustainable alternatives to single-use plastic, comparing results of microplastic analysis will determine the measure of success.

With the focus on plastic pollution gathering more and more momentum, SOCOTEC UK can support all projects wishing to obtain data on microplastics content within various sample matrices, in addition to testing marine sediment samples for trace metals, Polychlorinated Biphenyls (PCBs), Polycyclic Aromatic Hydrocarbons (PAHs), Petroleum Hydrocarbon (THC), Organotin compounds,  Total Organic Carbon (TOC) and organochloropesticides (OCPs).

 

References:

https://www.hull.ac.uk/work-with-us/more/media-centre/news/2018/microplastics-found-in-mussels-from-uk-waters.aspx

https://www.greenpeace.org.uk/what-we-do/oceans/plastics/

https://www.mcsuk.org/news/nanoplastics_on_our_plates

 

Image Credit to Canal and River Trust

 

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