University of Otago, New Zealand


Te Tari Hua-Ruanuku

Raman Spectroscopy: A Useful Tool for Quantifying Environmental Impact of Plastics on our Beaches

Wednesday 6 April 2016

P. J. Clunies-Ross, G. P. S. Smith, K. C. Gordon, and S. Gaw

Geoff Smith in the lab
Geoff Smith standing next to the Raman microscope while holding a sedimentary sample and a UV flashlight.

A recent study involving collaboration between Otago and Canterbury Universities has shown the value of light-based analytical techniques for locating and identifying microscopic plastic pollutants which are washing up on New Zealand beaches. In a new approach to investigating this problem, ultra-violet light was used to locate these pollutants among the sedimentary debris collected from beaches around Christchurch. Once located, Raman microscopy, a technique which utilises a laser with a microscopic spot size, was used to identify these tiny plastics.

Results showed that polystyrene (54.8%), polyethylene (20.5%), and polypropylene (11.0%) were the most commonly found microplastics, with only 13.7% of the plastics found being outside of these three categories. While the estuarine and harbour environments were not too badly affected, the exposed beachfronts bore the brunt of the problem. The sources of these plastics are still not known, but needless to say, curbing our reliance on plastic packaging and recycling whenever possible is necessary in order to keep New Zealand beaches beautiful.