Microplastics are entering the environment from wastewater treatment

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New Zealand
https://www.flickr.com/photos/oregonstateuniversity/21282786668/
https://www.flickr.com/photos/oregonstateuniversity/21282786668/

Researchers regularly sampled effluent from three wastewater treatment plants in Canterbury, finding they are a significant source of microplastics in the marine environment. The treatment plants are not currently designed to remove microplastics, and the researchers estimate that every day 240,000 microplastics enter the coastal environment from the effluent coming out of those three plants. Wastewater becomes contaminated with microplastics due to the use of synthetic clothing and textiles and other plastic products, and the most common microplastics detected were polyester, polyethylene, and polypropylene. The authors say further work is needed to better understand which microplastics are entering the treatment plants, and which are discharged in the effluent.

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Despite this work being published in a New Zealand focussed journal, the findings and implications have far wider reaching global implications. Like those in New Zealand, waste water treatment plants in Australia and much of the rest of the world are the final port of call for water before it is released into the environment. This research very clearly highlights that a substantial microplastic load, and variety of microplastics, enters environmental waters post the water treatment process. If waste water treatments plants are not operationally capable or suitable for the purpose of harvesting microplastics from water during the treatment process, then we are left with an unchecked contribution of microplastics into the environment. Assuming that waste water treatment plants discharge to rivers - the superhighways for water transiting to the ocean - then this presents yet another management challenge for those actively seeking to reduce the plastic pollution load in the near-shore and marine environments. 

Last updated:  23 Oct 2021 3:48pm
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Declared conflicts of interest None declared.
Journal/
conference:
New Zealand Journal of Marine and Freshwater Research
Research:Paper
Organisation/s: University of Canterbury, ESR (Institute of Environmental Science and Research Ltd), Northcott Research Consultants Ltd, Hamilton, New Zealand
Funder: We would like to thank The Institute of Environmental Science and Research (ESR), The Brian Mason Scientific and Technical Trust, and The Evan’s Fund for providing funding that supported this project.
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