Microplastics

Analysis of microplastics in surface water

Microplastics are fast becoming an emerging contaminant of concern as we begin to understand how they are dispersed throughout the environment and could possibly affect human health.

The term microplastics was first used to describe microscopic pieces of plastic in marine sediment and water by Thompson et.al. in 2004. The definition has since been refined and while there is no accepted all-inclusive definition Frias et.al. has suggested the following to be used:

"Microplastics are any synthetic solid particle or polymeric matrix, with regular or irregular shape and with size ranging from 1 μm to 5 mm, of either primary or secondary manufacturing origin, which are insoluble in water"

Testing of microplastic

ALS uses several different methods to identify the level of microplastics in water samples

The initial method used by ALS, “Nile Red Method” uses a dye to stain plastic particles. Identification and particle count are performed using image analysis.

This method is typically used to measure particles down to 100 μm in size.

As the method development continues ALS has also implemented the use of FTIR for microplastics analysis. There are two different types of FTIR instrumentation used by environmental laboratories for the purpose of identifying microplastics: AVR-FTIR and imaging μ-FTIR.

ATR-FTIR is typically used to measure particles down to 50 μm in size while imaging μ-FTIR is typically used to measure particles down to 10 μm in size.