National Pollutant Release Inventory Submittal Form

Industry Sectors to be affected by the change:

The knowledge concerning the types of industry sectors that could incidentally produce/release NDMA and would be affected by this addition is incomplete.

Industrial sectors/sources identified in the PSL Assessment Report (identified from a PSL2 Use Pattern Survey or scientific literature) or that have reported to ARET or the TRI include: rubber manufacturers, tire manufactures, organic chemical producers, pesticide manufacturing and pesticides contaminated with NDMA, drinking water and wastewater treatment plants, land application of sewage sludge, food processing and food processing waste, leather tanning manufacturers, foundries and dye manufacturing, waste disposal (used oil recycling or refining and incineration).

There are no industrial or commercial uses of NDMA in Canada. NDMA is not imported into Canada and is not listed on the Domestic Substances List (DSL). The PSL2 Assessment Report indicated that in the past, NDMA was used in Canada and other countries in rubber formulations, as a fire retardant and in the organic chemical industry as an intermediate, catalyst, antioxidant, additive for lubricants and softener of copolymers.

While there are no direct uses of NDMA, there are many sources, as it is produced naturally as a result of biological, chemical or photochemical processes. It may form in water, air and soil by ubiquitous, naturally occurring precursors found in these media, classified as nitrosatable substrates (secondary amines) and nitrosating agents (nitrites). Through similar reactions it is also produced inadvertently as a by-product and contaminant in a range of industrial situations, and in the processing, preservation and/or preparation of food (see above).

NDMA was determined to be toxic as a consequence of its risk to human health. Based upon laboratory studies in which tumours have been induced in all species examined at relatively low doses, NDMA is clearly carcinogenic, with a very strong likelihood that the mode of action for the induction of tumours involves direct interaction with genetic material. Qualitatively, the metabolism of NDMA appears to be similar in humans and animals; as a result, it is considered highly likely that NDMA is carcinogenic to humans, potentially at relatively low levels of exposure. Long-term studies have shown that NDMA primarily affects the liver.

The acute and chronic effects of NDMA have been studied in a variety of species of plants and animals. Short term studies have shown that NDMA is moderately toxic to wildlife as well as laboratory and domestic animals.

NPRI Substances that may Contain NDMA as a Contaminant During Manufacture, Processing or Otherwise Use

Some evidence suggests that there are measurable levels of NDMA contamination in dimethylamine (DMA) products (e.g. chemical production of DMA based solvents such as dimethylformamide, dimethylacetamide). DMA is on the NPRI at the 10 tonne reporting threshold. Substance was added in 1999. A total of three companies have filed reports on DMA since 1999, two of which also report NDMA to ARET (Chinook Group Ltd. and Safety Kleen).

Although the contribution to overall exposure from industrial sources is expected to be low, this statement can not be supported until the substance is added to the NPRI. As NDMA is a potent carcinogen, very small amounts of release could be significant. The Assessment Report concluded that "On the basis of limited information from short-term monitoring surveys of ambient air and water near industrial facilities, the priority for investigation of options to reduce exposure to NDMA in the vicinity of such point sources is considered high. It is recommended, therefore, that there be additional investigation of the magnitude of exposure of populations in the vicinity of point sources to assist risk management actions".

NDMA is considered to be "toxic" as defined in Section 64 of the Canadian Environmental Protection Act, 1999 (CEPA 1999). It is a Track 2 substance. The risk management strategy is currently under development and addition of NDMA to the NPRI is a part of that strategy. Addition of NDMA to the NPRI supports many of the objectives above, particularly to support regulatory initiatives and to identify priorities for action.

PSL II Use Pattern Survey reported a combined total of 1.7 kilograms of NDMA emitted in air and water for 1996. Eight companies responded to the survey. Out of these eight companies, four of them were participants in the Accelerated Reduction/Elimination of Toxics (ARET) program . For the same year (1996), ARET participants reported 3 kg of total emissions of NDMA to the environment. ARET companies achieved a 94% reduction in emissions level from 1993 to 1997 and projected a 100% reduction by year 2000 (87 grams). Actual reductions did not achieve 100% reduction by 2000. Increases above projected values (136 instead of 117g) were due to the release to water from one chemical producer, but releases from this facility dropped dramatically in 2001 (9 grams). The Canadian Chemical Producer's Association have reported 0 tonnes of emissions for NDMA in their 1998 Emissions Inventory Report and projected the same for 1999 and 2003.

NDMA is on the TRI. The reporting thresholds for this chemical are 25,000 pounds for manufacturing or processing and 10,000 pounds for otherwise using. There was one report filed for this chemical in 2000 by the U.S. Filter Recovery Services but it was a Form A report which does not include releases. The fugitive air release from U.S. Filter Recovery Services in 1999 was in the range of 1-10 pounds. Safety Kleen data for 1998 shows a fugitive release to air of 111 pounds, and a release of 18 pounds from the stack (air). There was no reports filed in the years 1994-1997.

ARET is a voluntary mechanism that in this case is not deemed to be comprehensive enough to support risk management actions.

NDMA is not on the NPRI in another form.

An alternate threshold of 10 grams, release-based is proposed for consideration by stakeholders. Ten grams was chosen as releases reported to ARET are in the order of grams. Releases reported to the TRI are in the order of 1-10 pounds. A release-based threshold was chosen as the substance is incidentally manufactured.

As this substance is not a Track 1, an LOQ based threshold is not appropriate. However, NPRI has yet to determine a reasonable reporting threshold for carcinogens, as well as a reasonable alternate threshold for Track 1 substances where LOQs will not be developed. An ATH needs to be developed that is not activity-based for when activities cannot be adequately determined, and is not MPO based for when the substance is incidentally manufactured. NDMA is a good example of a very highly hazardous substance that falls into this category.

This is a difficult substance for risk managers due to the state of knowledge surrounding industrial releases of NDMA. It will also be a challenging substance for NPRI, as for the possible exception of DMA manufacturing, it will presumably be difficult for NPRI to provide guidance to stakeholders.