1.4 Comparing PRTR Data from Canada, Mexico and the United States

1 Overview of Releases and Transfers in North America, 2014–2018

1.4 Comparing PRTR Data from Canada, Mexico and the United States

It is important to remember that certain considerations should be taken into account when interpreting North American PRTR data. These include the composition and size of each country’s industrial and economic sectors, as well as key differences among national PRTR reporting requirements relative to industrial activities and pollutants.

Comparing PRTR data from Canada, Mexico, and the United States

Taking Stock presents PRTR data from Canada, Mexico, and the United States, providing the most comprehensive picture of industrial releases and transfers of pollutants currently available for North America. This overview covers data that may have been reported differently in each country due to unique national reporting requirements and the different methods used by facilities to calculate their emissions. The characteristics of each PRTR program are described in “Understanding Taking Stock” and this information provides context to better understand reported pollutant releases and transfers throughout the region.

Together, these factors can have significant impacts on the resulting picture of releases and transfers across the region, particularly relative to a few of the top reporting sectors. For example:

The data reported by the electricity generation and distribution sector (NAICS 2211) are greatly influenced by each country’s unique electricity generation profile. While over one-quarter of Canada’s energy comes from hydroelectricity (particularly in the provinces of British Columbia, Québec, and Ontario), fossil fuels such as coal, oil and natural gas supply a much greater proportion of the energy requirements of Mexico and the United States.
The impacts of the differences among national PRTR reporting requirements are clearly illustrated by the data for the oil and gas extraction sector (NAICS 2111). This sector is subject to reporting in Canada and Mexico, but not the United States (however, as of the 2022 reporting year, US natural gas processing plants will be required to report).
Similarly, the water and sewage treatment sector (NAICS 2213) is subject to Canada’s PRTR, while in Mexico the sector is under municipal jurisdiction. However, any Mexican facility that releases wastewater to national water bodies must report to the RETC (hence the data from a number of water and wastewater treatment plants in that country). In the United States, publicly-owned treatment works (POTWs) are not subject to the TRI and therefore, the available data are for the wastewater treatment activities of a few industrial sectors and federal government facilities.

The impacts of the differences among PRTR reporting requirements relative to pollutants are shown in Figure 7, which indicates that only half of the top 20 substances reported between 2014 and 2018 are subject to reporting in all three countries. In fact, both manganese and zinc compounds—the top pollutants in terms of reported amounts—are subject to reporting in Canada and the United States, but not Mexico (with the exception of one zinc compound). Two others—barium compounds and total phosphorous—are subject to reporting only in the United States or Canada (respectively).^[6] The relative importance of these pollutants to the total amount reported each year underscores the need for more comparable reporting requirements to capture the releases and transfers of industrial activities across the region.

[6] Note about the comparability of zinc and phosphorous compounds: Unlike Canada and the United States, Mexico’s RETC includes only one zinc compound (zinc phosphide) and does not include phosphorous compounds. The US TRI covers certain individual phosphorous containing compounds, but reporting is not limited to the weight of phosphorous (unlike the Total Phosphorous category in Canada). Both the Canadian NPRI and US TRI require separate reporting of yellow/white phosphorous.