A comprehensive investigation of industrial plastic pellets on beaches across the Laurentian Great Lakes and the factors governing their distribution

Patricia L Corcoran; Johanna de Haan Ward; Ian A Arturo; Sara L Belontz; Tegan Moore; Carolyn M Hill-Svehla; Kirsty Robertson; Kelly Wood; Kelly Jazvac

doi:10.1016/j.scitotenv.2020.141227

A comprehensive investigation of industrial plastic pellets on beaches across the Laurentian Great Lakes and the factors governing their distribution

Sci Total Environ. 2020 Dec 10:747:141227. doi: 10.1016/j.scitotenv.2020.141227. Epub 2020 Jul 25.

Authors

Patricia L Corcoran¹, Johanna de Haan Ward², Ian A Arturo³, Sara L Belontz³, Tegan Moore⁴, Carolyn M Hill-Svehla⁵, Kirsty Robertson⁴, Kelly Wood⁴, Kelly Jazvac⁶

Affiliations

¹ Department of Earth Sciences, University of Western Ontario, London, ON, Canada. Electronic address: pcorcor@uwo.ca.
² Department of Statistical and Actuarial Sciences, University of Western Ontario, London, ON, Canada.
³ Department of Earth Sciences, University of Western Ontario, London, ON, Canada.
⁴ Department of Visual Arts, University of Western Ontario, London, ON, Canada.
⁵ Surface Science Western, University of Western Ontario, London, ON, Canada.
⁶ Department of Studio Arts, Concordia University, Montreal, QC, Canada.

PMID: 32781316
DOI: 10.1016/j.scitotenv.2020.141227

Abstract

Industrial, pre-consumer pellets are a major type of plastics pollution found on shorelines worldwide. This study investigates the distribution and characteristics of plastic pellets accumulated on beaches of the Laurentian Great Lakes of North America and provides a "snapshot" of pellet distribution in a lake system that accounts for 21% of the world's freshwater reserves. We sampled pellets simultaneously from 10m² quadrats on 66 beaches and characterized the 12,595 pellets collected (average of 19.1 pellets/m²). Forty-two beaches contained pellets and 86% of the pellets were found on three beaches: Rossport (Lake Superior), Baxter (Lake Huron), and Bronte (Lake Ontario). The number of pellets on each beach was compared with factors hypothesized to control their accumulation. In general, positive correlations were found between pellet abundance and watershed population, number of plastic-related industries, and proximity to a river mouth, although for Lake Superior, abundance was related to a train spill that took place over 10 years ago. Beach grain size appears to be related to pellet abundance, with very fine sand, fine sand and medium sand containing the greatest number of pellets. All pellets were visually characterized based on size, color, shape, weathering, and distinguishing traits. The predominant color was white, oblate shapes were most common, and the main distinguishing trait was a dimple. Most pellets showed little evidence of weathering, with the weathered samples mainly from Lakes Erie and Ontario. Lake Ontario pellets were the most varied, with 6/7 shapes, 35/40 colors, and 21/25 distinguishing traits, indicating a wider range of pellet sources compared to the other lakes. Polymer compositions were mainly polyethylene (PE) and polypropylene (PP). Our results will lead to increased recognition of regional pellet pollution in the Great Lakes watershed, thereby motivating change during their production, transport and use.

Keywords: Grain size; Laurentian Great Lakes; Pellet spills; Plastic industry; Plastic pellets; River mouth.