2 Feature Analysis: Off-site Transfers to Disposal in North America, 2014–2018
2.4 Analysis of Off-site Transfers to Disposal, 2014–2018
2.4.1 Regional overview
The releases and transfers reported by North American facilities, presented in chapter 1, totaled nearly 5.3 billion kg in 2018, up from approximately 5.1 billion kg in 2014 (an increase of about 3 percent). By comparison, off-site transfers to disposal ranged from 334.5 million kg in 2014 to approximately 337 million kg in 2018 (an increase of 0.7%) and represented about 6% of total annual releases and transfers. These proportions are reflected in the Canadian and US data; however, in Mexico, transfers to disposal increased from just over 3 million kg in 2014 (12% of the country’s total releases and transfers) to almost 16.5 million kg in 2018 (34% of the total) (Table 13).
Table 13. Off-site Transfers to Disposal in North America, by Country, 2014-2018
Note: Differences among national reporting requirements need to be considered when interpreting North American PRTR data.
As mentioned in chapter 1, the total number of reporting facilities in North America did not vary significantly between 2014 and 2018, with the exception of Mexico, which saw an increase of 25%. The increase in the number of Mexican facilities reporting transfers to disposal during this period was lower (about 12%) (Table 14).
Table 14. Number of Reporting Facilities in North America, 2014–2018
Note: Differences among national reporting requirements need to be considered when interpreting North American PRTR data.
The Mexican data, which are explored in greater detail in section 2.4.4, show that just a few of these newly-reporting facilities drove the large increases in transfers to disposal between 2014 and 2018. The aforementioned addition of substances subject to reporting in Mexico, as of 2014, also resulted in modest increases in transfers to disposal (up to 600,000 kg each year, with the exception of 2017).
Figure 13 shows the transfers to disposal reported by North American facilities from 2014 to 2018. It reveals that transfers to landfills or surface impoundments accounted for about 155 million kg (46% of the total) in 2018, a decrease of about 15% from the 179 million kg reported in 2014.
Figure 13. North American Transfers to Disposal, by Category, 2014–2018
Transfers to underground injection ranked second and accounted for 17–20% of the annual totals, followed by transfers to stabilization or treatment prior to disposal, which increased by 30% during this period (from about 40 million kg in 2014 to 52 million kg in 2018).
Transfers to “other disposal (unknown)” ranked fourth among reported disposal practices each year. As described in Table 6, this category can encompass a variety of activities and processes; however, these details are not usually reported to the PRTRs.
Transfers to land application, the 5th-ranked off-site disposal practice, increased by more than 40% during this period (from approximately 12 million kg in 2014 to more than 17 million kg in 2018). Finally, transfers to storage prior to disposal represented between 7 million kg and 9 million kg each year.