Hunter, E. C., de Vine, R., Pantos, O., Clunies-Ross, P., Doake, F., Masterton, H., & Briers, R. A. (2022, January). Quantification and characterisation of pre-production pellet pollution in the Avon-Heathcote Estuary/Ihutai, Aotearoa-New Zealand. Microplastics, 1, 67–84. https://doi.org/ 10.3390/microplastics1010005.

Supported by the Avon-Heathcote Estuary Ihutai Trust and Lesley Bolton-Richie from Environment Canterbury in 2022, this study assessed the presence and characteristics of pre-production plastic pellets found in the Ihutai estuary. This was significant because plastic pollution continues to threaten important aquatic ecosystems and wildlife across the globe, including the Ihutai estuary in Canterbury. According to the authors of this study, understanding the characteristics and extent of plastic pollution is the first step towards improving environmental management.

The size, colour, morphology, degree of weathering and polymer type were measured for each pellet found. Overall, a total of 3819 plastic pellets were found in the estuary. 86% of the pellets were predominantly clear, 54% were around 3mm in size, 41% showed moderate weathering, and 53% were made of low-density polyethylene. The pellet accumulation, abundance, and characteristics varied between sites, implying influence from river inflows, weather conditions, and proximity to stormwater outlets. It was also found that concentrations of pre-production pellets in Te Ihutai was relatively high compared to international studies, and that the overall concentration of microplastics in the estuary was likely to be higher still. These findings presented a hazard to local wildlife and ecosystem health, leading the researchers to call on the plastics industry in Ōtautahi Christchurch to address pellet loss and take responsibility.