Quantification of microplastics by count, size and morphology in beverage containers using Nile Red and ImageJ

Shujuan Chen,Saamon Legoski,Christopher Mawhorter,Yue Li

doi:10.2166/wh.2020.171

Abstract

Abstract Abundant evidence of microplastics (MP) found in the environment, and its toxicity effect in animals calls for human-related research. However, well-established quantitative controlled studies on the potential route of human exposure to MP are still sparse. MP count, size and morphology in 15 polylactic acid (PLA)-lined plastic cups and 15 PLA-lined paper cups were examined using Nile Red fluorescence tagging, microscopic photography, and morphology assessment and quantification based on ImageJ. In the plastic cups, the count and area of MP fibers were found to be significantly higher compared with blanks (p &lt; 0.05), but not MP particles or total MP. In paper cups, count or area was not significantly different in terms of MP particle, MP fibers or total MP. No interesting trend was observed in the distribution regarding the size of MP particles or fibers. These results indicate that selected paper cups and plastic cups could be considered as safe beverage containers, but further research on the toxicological effects of MPs in different morphologies released from plastic cups on human health is needed.

Highlights

Microplastics (MPs) are water-insoluble, synthetic polymers of diverse shapes, with sizes ranging from 1 μm to 5 mm (Frias & Nash )
Based on the background knowledge above, we specified our study aims as the following: (1) to determine whether beverage containers are a significant source of microplastic exposure, (2) to determine whether different types of beverage containers have different MP levels by count and size, (3) to determine whether the results are modified by the morphology of MPs and (4) to determine whether there are distribution differences between different morphology of MPs
We settled on a modified method that consists of Nile Red (Sigma-Aldrich 19123) fluorescence tagging, microscopy (OLYMPUS BX60PE, 10× zoom), followed by morphology assessment and quantification based on ImageJ and statistical analysis

Summary

Introduction

Microplastics (MPs) are water-insoluble, synthetic polymers of diverse shapes, with sizes ranging from 1 μm to 5 mm (Frias & Nash ). MPs have become an emerging public health issue because a number of studies have shown that MPs are ubiquitous everywhere in our surrounding. The source of MPs can come from the breakdown of larger plastics, such as water bottles, and from the use of synthetic polymers during the manufacturing process (US Department of Commerce ). Chen et al | Quantification of microplastics in beverage containers

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