Synthetic shorelines in New Zealand? Quantification and characterisation of microplastic pollution on Canterbury's coastlines

Abstract

Microplastics are persistent environmental contaminants found in marine environments worldwide. Microplastic particles isolated from coastlines in the Canterbury region of New Zealand were quantified and characterised. Sediment samples were collected from ten locations representing exposed-beach, estuarine and harbour environments in both urban and non-urban settings. Particles were isolated from sediments using a NaCl density-separation procedure and quantified and characterised with a combination of optical/fluorescence imaging and micro-Raman spectroscopy. Microplastics were detected at 8 out of 10 locations, at concentrations ranging from 0 – 45.4 particles kg⁻¹ of dry sediment. The majority of microplastics were identified as polystyrene (55%), polyethylene (21%) and polypropylene (11%). Microplastic concentrations in exposed-beach environments were significantly greater than harbour and estuarine environments.