In both Canada and the United States of America, the type and distribution of the sources of pollution are monitored yearly, by federal and sub-national environmental agencies, and are made publicly available in the form of data, reports or maps. There are no national level resources for polluted sites or soil pollution. Partial national level resources do exist with more complete listings at the state (United States of America) and province/ territorial (Canada) level (Table 3).
The Federal Contaminated Sites Action Plan (FCSAP) addresses federally owned or controlled polluted sites in Canada (Environment and Climate Change Canada, 2015). The aim is to assess the risk to human health in regard to the polluted site and also to allocate funds within federal custodians to deal with the high priority polluted sites. The document called “Federal approach to contaminated sites” outlines the 10 steps process to provide a common approach in the assessment and remediation of polluted sites. In Canada, the polluter pays principle is enforced and when sites are owned by provinces, territories and federal government, they are responsible for the cost of the polluted site (Environment and Climate Change Canada, 2019c).
The Canadian Federal Contaminated Sites Inventory (FCSI) includes all known polluted sites or sites that are under federal jurisdiction (transportation site, such as airports and marine ports, but also military sites, indigenous reserves, etc.) or sites for which the Government of Canada has recognized that it may be appropriate to assume all or some level of responsibility (Environment and Climate Change Canada, 2012). Inclusion on the list results from a step-by-step process carried out to roughly estimate whether a pollution is occurring that exceeds the guidelines agreed to by federal, provincial and territorial environment ministers (Environment and Climate Change Canada, 2019c). The FCSI is annually updated and includes information regarding the location of the sites, the degree of pollution, the medium polluted, the type of contaminants, the stage at which the site is currently under for its identification are remediation and how much liquid or solid media has been treated so far. Currently there are 23 694 federal sites in the FCSI, of which 4 980 are sites under remediation and 1 869 are suspected sites. About 16 845 are listed as closed because the remediation process was completed, and no further action is needed.
Established in 1992, the National Pollutant Release Inventory currently collects information on the release of more than 320 substances. Under the authority of the Canadian Environmental Protection Act (CEPA) 1999, facilities in Canada that meet the requirements, have to report to the NPRI on an annual basis. Reported contaminants include toxic substances, air contaminants and other substances of concern. The information obtained through NPRI helps set environmental priorities.
The releases of contaminants are considered for air, water and land. In the case of land, the releases considered are spills, leaks or other land releases except regulated disposals. The inventories also track the disposal and transfer of substances. Disposals methods include landfill, land application and underground injection and can be done at the facility (on-site) or elsewhere (off-site) (Environment and Climate Change Canada, 2017). The data collected by NPRI is publicly available as datasets or as mapping products (Environment and Climate Change Canada, 2017b). In 2017, the majority of the facilities reporting to the NPRI were in Alberta (2 658) and Ontario (1 637). The majority of Alberta facilities (76 percent) are oil and gas extraction operations. In Ontario, 69 percent of the reporting facilities were manufacturing operations (Environment and Climate Change Canada, 2019b). Canada has also developed Environmental Sustainability Indicators (CESI) with the aim to monitor Canada’s trend toward environmental sustainability regarding climate change and air quality, water quality, contaminants emissions and human health (Environment and Climate Change Canada, 2019d).
A single comprehensive data monitoring system of all polluted sites in the United States of America does not exist. The largest and most severely polluted sites are tracked at the national level and others at the state or local level. The number and status of polluted sites continually changes due to newly polluted site discovery and sites that are delisted due to successful remediation.
In the United States of America, polluted sites are divided into different categories according to the level and type of contamination and regulations under which they are monitored and remediated. The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), i.e., Superfund, National Priorities List sites (NPL) comprises the most seriously polluted sites in the United States of America and include industrial facilities, waste management sites, mining and sediment sites, and federal facilities such as abandoned mines, nuclear, biological, chemical, and traditional weapons production plants, and military base industrial sites (Figure 12). Superfund sites in the United States of America currently on, proposed and removed from the NPL can be viewed on a map (US EPA, 2019q). There are 1 333 active federal and state NPL sites, 48 proposed and 424 closed sites.
The United States of America Resource Conservation and Recovery Act (RCRA) and Corrective Action Program oversees almost 4 000 cleanups across the country. These laws focus regulate facilities that store or handle hazardous solid waste to prevent contamination and require remediation where it has occurred (US EPA, 2014a). These facilities include chemical manufacturing plants, oil refineries, lead smelters, wood preservers, steel mills, commercial landfills, federal facilities, and a variety of other facilities.
There are an estimated 450 000 brownfields sites in the United States of America (US EPA, 2019f). US EPA’s Brownfield program works with states, communities and other stakeholders by providing grants, site assessment contractor, and tools and technical assistance. EPA reported that approximately 188 million people live within three miles of a CERCLA, RCRA, or Brownfields site, i.e., roughly 59 percent of the American population, including 60 percent of all children in the United States of America under the age of five (US EPA, 2019b).
Other sites that have been categorized are under specific monitoring and cleanup programs are land polluted with radioactive and other hazardous materials, as a consequence of nuclear weapon production, testing and research. Military facilities are often polluted with discarded munitions, unexploded ordinance; and building demolition debris (US EPA, 2019g).
The Emergency Planning and Community Right-to-Know Act (EPCRA) requires chemical release information from currently operational facilities to be submitted to US EPA annually for publication in the TRI. In 2017, more than 21 000 facilities submitted TRI data to EPA (US EPA, 2019d).