Bromine Content Differentiates between Construction and Packaging Foams as Sources of Plastic and Microplastic Pollution

Plastic foams are used to make food packaging, consumer product protective packaging, and building insulation materials–each of which are reported in the environment. This study investigated the contributions of construction and packaging applications to foam plastic litter using visual characteristics and the presence of bromine (Br) from flame retardants as an identifying signature. A foam source library of 86 examples that included building materials and packaging demonstrated that 96% of building materials contained Br while only 5% of foam packaging did, as measured by hand-held X-ray fluorescence (XRF) spectrometry. The XRF enabled the detection of Br in particles down to 1 mm in size, enabling both macro- and microplastic foams to be quantitatively assessed for the relative contributions of construction-based activities and packaging sources to the abundance of foam found on Toronto-area beaches, in tributaries, and in Lake Ontario waters adjacent to Toronto. Beach and surface water surveys revealed 58% and 51% of samples, respectively, contained concentrations of Br consistent with construction foams. This significant proportion highlights a need for greater attention toward the management of construction foam waste, for example, developing and implementing best management practices at active sites to prevent foam litter from entering the environment.