In Pursuit of Polystyrene: determining the sources of polystyrene foam in Lake Ontario

Polystyrene foam is one of the many types of plastic pollution found in our environment. In Toronto, reports of foam littering streets, beaches and slips are commonplace. The question is, where does it all come from? Common sources are takeout containers and packaging, another is likely construction.

EPS packaging foams in untied recycling bags and overflowing bins waiting for collection.

Project Overview

The aim of this project is to determine how much of the foam littering our waterways comes from construction and packaging. Through a better understanding of this source, we aim to inform policies that mitigate construction and packaging foam pollution. At the U of T Trash Team, we focus on the many sources of plastic pollution (e.g., pellet loss from the plastic industry, microfibers from washing machines), doing solutions-based research that aims to mitigate diverse sources – sometimes one source at a time.


Learn More about Polystyrene

Expanded polystyrene (EPS) and extruded polystyrene (XPS) are two types of polystyrene foam used for insulation in building walls. EPS foam is a compilation of numerous small polystyrene beads and made up mostly of air. XPS foam is more rigid and dense. Another type of foam, called polyurethane foam, expands when sprayed onto walls and is also a popular option used for building insulation. If these foams are used IN the walls, how do they make their way to our environment?

One route into the environment occurs during the installation of EPS sheets and requires scraping off some of the polystyrene beads, resulting in “polystyrene snow”. Similarly, trimming XPS sheets and spray polyurethane foam to fit wall structures produces small pieces of foam that can be disregarded during post-construction cleaning. Due to its light and airy texture, these foam particles are free to be swept away by runoff or blown via wind – entering freshwater bodies and contributing to plastic pollution.

EPS Insulation boards on houses under renovation (left). Scraping and trimming of boards emit “polystyrene snow” (right), as seen here lining the gutters across the street. This debris can be easily blown by the wind and enters storm basins during rainfall.

Generally, polystyrene foam used in building activities contains chemical flame retardants, while other polystyrene foams do not. By investigating whether foams found in the environment have chemicals, we can identify the foam particles used in insulation and determine what proportion of polystyrene foam litter originates from construction.

This project aims to:
  1. Determine the source contributions of polystyrene foam
  2. Develop portable X-ray Fluorescence (XRF) and pyrolysis gas chromatography mass-spectrometry (GCMS) analysis methods to detect bromine
  3. Improve education initiatives to reduce polystyrene foam and plastic pollution

This project is led by Gloria Gao, a recent graduate from University of Toronto. She holds an Honours BSc, specializing in Ecology and Evolutionary Biology. During her undergraduate, she was a Research Assistant with the Rollinson Lab, and developed an independent research project investigating morphological abnormalities in a population of spotted salamanders in Algonquin Provincial Park. Gloria also volunteers as a Waste Literacy Instructor for our classroom visits.

For more information, please email Chelsea Rochman or Gloria Gao.

This project is in collaboration with the Ontario Ministry of the Environment, Conservation and Parks.