Tracking Canadian mercury emissions from products containing mercury

摘要

Tracking emissions of mercury from products is particularly challenging; yet it is a high priority because of the severe toxicity of mercury. A lifecycle analysis approach has been used for estimating mercury emissions from ten product categories in Canada including dental amalgams, fluorescent lamps, other mercury-containing lamps, switches and relays, thermostats, batteries, measurement and control devices, thermometers, tire balancers and automotive switches. The lifecycle considers releases to air from manufacturing, sales, breakage, transportation/storage, recycling and ultimate disposal. The models were last updated in 2008 and included limited Canadian data at the time, with emissions being carried forward ever since. Furthermore, a number of changes have taken place since the last update in terms of use, handling and disposal of Hg in products. This study updated the models through incorporating more Canadian information and changes in the lifecycle of products (e.g., use and management) from 2009 to 2017. This was possible by considering modifications in product uptake (i.e., importation and manufacture), regulatory changes (notably the Products Containing Mercury Regulations), and national or regional end-of-life management practices through a literature review along with expert consultation. Our study found that most product categories are no longer manufactured in Canada and recycling has increased over other end-of-life disposal options from 2009 to 2017. Overall, Hg emissions from all product categories declined during our study period. One of the highest emission sources came from dental amalgams associated with human cremation and use of this product in dental offices. Additionally, foundries were associated with some of the highest releases to air from other product categories. The lowest emissions came from manufacturing of lamps, releases from live Canadians that have dental amalgams, sludge land application and sludge landfill disposal from a number of product categories. This study provides new insights on Hg emissions from products in Canada and will be of great importance to the general public, air pollution modelers and those alike.