Section 4: Polycyclic Aromatic Hydrocarbons (PAHs)

• 4.1 Introduction, History and Intent
  • 4.1.1 Wood Preservation
• 4.2 Substances
• 4.3 Reporting Criteria
  • 4.3.1 Wood Preservation Using Creosote
• 4.4 What You Must Report
  • 4.4.1 Units

Polycyclic aromatic hydrocarbons (PAHs) may be used as commercial chemicals or incidentally manufactured. There were two substances on the NPRI prior to 2000 that are considered PAHs - anthracene (CAS No. 120-12-7) and naphthalene (CAS No. 91-20-3). These substances are commercial chemicals used in significant quantities, and are less toxic than the 17 PAHs added at an alternate threshold to the NPRI for 2000. Environment Canada has retained the 10-tonne manufacture, process and other use reporting threshold for anthracene and naphthalene.

PAHs are listed as a group on the List of Toxic Substances under the CEPA (1999) (see Appendix 6). Many individual PAHs meet criteria for persistence, bioaccumulation and toxicity, as defined by various international bodies. PAHs as a group have been assigned Track 2 status under the CEPA because many sources are natural rather than resulting from human activity.

Environment Canada considered various reporting criteria for the alternate-threshold PAHs. Individual reporting of PAHs is necessary as Environment Canada has international obligations under the UN ECE Persistent Organic Pollutants (POPs) Protocol to report releases of four indicator PAHs (noted in Table 2). No national, facility-specific data exist for PAHs, and reporting to the NPRI will be the most efficient method to gather these data from facilities.

The lack of facility-specific data prevented Environment Canada from performing a release analysis for PAHs to select an appropriate alternate reporting threshold. A 50-kg threshold level for the PAH category will meet Canada's requirements for reporting to the UN ECE POPs Protocol. The 50-kg reporting threshold is consistent with reporting to the US EPA Toxics Release Inventory, which lowered the reporting thresholds for its PAH group to 100 pounds (45.4 kg) for the 2000 reporting year.

In selecting individual PAHs to be reported to the NPRI at alternate thresholds, Environment Canada and the Work Group on Substances examined several lists. The final list selected for inclusion is based on the PAHs classified as persistent, bioaccumulative and toxic substances by Environment Canada's Accelerated Reduction/Elimination of Toxics (ARET) program, known as ARET Group A. Based on ARET data collected up to 1997, no facilities reported releases for two of the 19 PAHs on the ARET list (1,6- and 1,8-dinitropyrene). Environment Canada could find no information on releases in Canada and no emission factors, so these two PAHs were excluded from the NPRI list.

Since these 17 PAHs are predominantly incidentally manufactured and released or transferred from facilities, rather than used as commercial chemicals, Environment Canada set alternate reporting criteria based on releases and transfers resulting from incidental manufacture.

Special criteria for PAHs from the wood-preservation sector are included in the NPRI at the request of the Issue Table for the Wood Preservation Sector Strategic Options Process. The Issue Table is developing reduction strategies for CEPA-toxic substances released to the environment by this sector. The members of the wood-preservation sector have committed to reporting all releases and transfers of CEPA-toxic substances to Environment Canada, with no quantitative reporting criteria. They chose the NPRI as the reporting mechanism. A facility is required to report any of the 17 individual PAHs released on site or transferred off site from a wood-preservation process using creosote. Environment Canada is preparing guidance specific to this sector for reporting of all applicable CEPA-toxic substances. Details are provided in Chapter 6.

The 17 individual PAHs that were added to the NPRI for 2000 at an alternate reporting threshold are listed in Schedule 1, Part 3, of the 2000 Canada Gazette notice and below in Table 2. These 17 PAHs are listed individually in the NPRI. On-site releases and off-site transfers must be reported for the individual PAH substances even though the 50-kg reporting threshold applies to the total releases and transfers of all 17 alternate-threshold PAHs.

* PAHs listed under the UN ECE POPs Protocol.

The NPRI has added an additional substance listing in the NPRI reporting software - "PAHs, total Schedule 1, Part 3" - which refers to all 17 PAHs or any combination thereof listed in Schedule 1, Part 3, of the 2000 Canada Gazette notice. The 17 PAHs may be reported under the substance listing titled "PAHs, total Schedule 1, Part 3" only if you do not have information available to estimate releases and transfers for any of the individual PAHs.

The substance-specific reporting criteria for the 17 PAHs listed in Table 2 are outlined in Schedule 2, Part 3, of the 2000 Canada Gazette notice and in Figure 3.

Figure 3: Reporting Criteria for the 17 PAHs Listed at an Alternate Threshold

With the exception of the activity of wood preservation (see section 4.3.1), you must submit substance reports on one or more of the 17 PAHs listed in Table 2 that were incidentally manufactured if, during the 2000 calendar year:

• employees worked a total of 20 000 hours or more, or the facility was used for an activity to which the 20 000-hour employee threshold does not apply (listed in Table 1 of Chapter 2)

AND

• any individual PAH (listed in Table 2) was incidentally manufactured, and the quantity of all of the PAHs incidentally manufactured and released on site or transferred off site together totalled 50 kg or more.

Except for the activity of wood preservation using creosote, the reporting criteria for PAHs are different from other NPRI-listed substances in the following ways:

• reporting the 17 PAHs is based on the quantities of the substances incidentally manufactured and released or transferred, not on the quantities manufactured, processed, or otherwise used
• you must consider the quantities of all 17 individual PAHs incidentally manufactured together in determining if your facility meets the reporting threshold, and
• the reporting threshold is 50 kg.

A facility used for wood preservation must submit a report for any of the 17 individual PAHs released on site or transferred off site from a wood-preservation process using creosote, regardless of the number of hours worked by employees.

Wood preservation means the preservation of wood using heat or pressure treatment, or both. There is no 50-kg reporting threshold for PAHs released or transferred from a wood-preservation process using creosote, since the PAHs are contained in the creosote and not incidentally manufactured. All PAHs released on site or transferred off site from wood-preservation processes using creosote must be reported, regardless of the quantity.

With the exception of the activity of wood preservation using creosote (see section 4.3.1), if your facility met the 50-kg reporting threshold for the 17 PAHs, you must report on-site releases and off-site transfers individually for each of the 17 PAHs that were incidentally manufactured and released or transferred.

If you do not have information available to estimate releases and transfers for any of the 17 individual PAHs, the PAHs may be reported together under the listing "PAHs, total Schedule 1, Part 3". You may report for the 17 individual PAHs, or "PAHs, total Schedule 1, Part 3", but not both. If you report under the listing of "PAHs, total Schedule 1, Part 3", indicate in the "Comments" field which substances are included in the data, if known.

You must account for total releases of the 17 PAHs from your facility to each environmental medium (air, water, land and underground injection) and transfers off site for disposal or recycling.

Anthracene and naphthalene are listed in Schedule 1, Part 1, of the 2000 Canada Gazette notice and the reporting criteria differ from those discussed in this Chapter. The reporting criteria for these substances are discussed in the Guide for Reporting. Anthracene and naphthalene must not be considered when you are determining whether your facility met the reporting criteria for the 17 alternate-threshold PAHs, nor in calculating on-site releases or off-site transfers of the 17 PAHs. Anthracene and naphthalene are not included under the "PAHs, total Schedule 1, Part 3" listing.

Report on-site releases and off-site transfers of individual PAHs listed in Schedule 1, Part 3, or "PAHs, total Schedule 1, Part 3" in units of kilograms (kg).