Identification and Quantification of Microplastics in Beverages in New Zealand

Abstract

Microplastic contamination in marine environments is well documented and of concern to marine life. There is a growing understanding that microplastics are dispersed widely through all environments, and it is expected that microplastics have contaminated human foods and the exposure to these particles are a concern to human health. Studies examining the contamination of food products are limited in number and of countries examined. The limited studies of food products of tap water, bottled water, beer, milk and salt have shown the presence of microplastics. Even more limited is the study of contamination of food products originating in New Zealand. The only food product produced in New Zealand that has been examined previously was salt, which showed the presence of microplastics. Identification of microplastics in food products has relied on visual examinations and spectral characterisation. Visual examination has limited applicability for analysis of microplastics as it is a non-characterising technique and spectral characterisation often has a detection limit of 20 μm. Pyrolysis – GCMS has shown growing use in the examination of environmental samples. This study has used pyrolysis – GCMS for the detection and characterisation of five common plastics and the quantification of PVC and PE in beverages. This study detected and quantified microplastics, by particle count and mass, in drinking water and a variety of alcoholic and non-alcoholic beverages. Polyethylene and polyvinylchloride were identified in some NZ beverage samples, reinforcing the belief that microplastic pollution is spread globally. The yearly dietary exposure to microplastics in humans was estimated at 3.7x104 microplastic particles or 1.4 mg of polyvinylchloride and 1.5 g of polyethylene, based on the limited beverages examined in this study. The detection of microplastics in other food products shows that further research should be conducted on the amount of microplastics in foods.