Triazines and Triazole Group - information sheet

1H-1,2,4-Triazol-3-amine
(Amitrole)
CAS Registry Number 61-82-5

1,3,5-Triazine-2,4,6(1H,3H,5H)-trione, 1,3-dichloro-, sodium salt
(Sodium dichloroisocyanurate; NaDCC)
CAS Registry Number 2893-78-9

1,3,5-Triazine-2,4,6-triamine, N,N,N’,N’,N’’,N’’-hexakis(methoxymethyl)-
(Hexa(methoxymethyl)melamine)
CAS Registry Number 3089-11-0

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Overview

  • The Government of Canada conducted a science-based evaluation, called a screening assessment, to address the potential for harm to Canadians and to the environment from 3 substances in the Triazines and Triazole Group.
  • Under the Canadian Environmental Protection Act, 1999 (CEPA 1999), the risk posed by a substance is determined by considering both its hazardous properties (its potential to cause adverse human health or ecological effects) and the amount of exposure there is to people and the environment. A substance may have hazardous properties; however, the risk to human health or to the environment may be low depending upon the level of exposure.
  • The ecological hazard and exposure potentials of these 3 substances were classified using the Ecological Risk Classification of Organic Substances Approach.
  • Substances in the Triazines and Triazole Group are associated with human health and/or ecological effects; however, the risk to Canadians is low at current levels of exposure. It is proposed to conclude that these 3 substances are not harmful to human health or to the environment at current levels of exposure.

About these substances

  • This screening assessment focuses on 3 of 6 substances referred to collectively as the Triazines and Triazole Group, under the Chemicals Management Plan (CMP). The 3 substances addressed are 1H-1,2,4-triazol-3-amine (commonly referred to as amitrole), 1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3-dichloro-, sodium salt (commonly referred to as sodium dichloroisocyanurate or NaDCC) and 1,3,5-triazine-2,4,6-triamine, N,N,N’,N’,N’’,N’’-hexakis(methoxymethyl)- (commonly referred to as hexa(methoxymethyl)melamine).
  • Two other substances in the Triazines and Triazole Group were determined to be of low concern to both human health and the environment through another approach. Conclusions for CAS RNs 101-37-1 and 288-88-0 are provided in the Screening Assessment for Substances Identified as Being of Low Concern using the Ecological Risk Classification of Organic Substances and the Threshold of Toxicological Concern (TTC)-based Approach for Certain Substances.
  • Additionally, the other substance (CAS RN 121-82-4) will be assessed in a future screening assessment.
  • According to information gathered by the Government, these substances do not occur naturally in the environment.  
  • In Canada, amitrole is registered as an herbicide. In 2014, the Pest Management Regulatory Agency (PMRA) conducted a re-evaluation of amitrole, and as a result, implemented a phase-out of its use as an herbicide, with the exception of its use on spruce bareroot nursery stock (seedbeds). In April 2018, PMRA initiated a special review of amitrole following the non-renewal (no longer approved) of pesticidal uses in the European Union.
  • NaDCC has uses in many pest control products (for example, algicides, bactericides, slimicides and a sanitizer). In addition, NaDCC can be used in a variety of other products available to consumers, including water treatment products, cleaning products and disinfectants.
  • Finally, hexa(methoxymethyl)melamine may be used in the manufacture of food packaging materials and other commercial products.

Human and ecological exposures

  • Exposure of Canadians to amitrole through the environment is expected to be minimal based on the current use of the substance. Products available to consumers containing amitrole have not been identified in Canada; therefore, exposure from such products to the general population is not expected.
  • Exposure of Canadians to NaDCC is expected to be from the environment (for example, drinking water from industrial and consumer down-the-drain releases) and from the use of products available to consumers, such as water treatment tablets and cleaning products.
  • Canadians may be exposed to hexa(methoxymethyl)melamine from drinking water. Exposure to this substance from food packaging is expected to be low.
  • According to information considered under the Ecological Risk Classification of Organic Substances Approach, amitrole and NaDCC were identified as having low ecological exposure potential, and hexa(methoxymethyl)melamine was classified as having a high ecological exposure potential due to its overall persistence and use quantities reported to the Government.

Key health and ecological effects (hazard)

  • To inform the human health effects characterization for amitrole, national and international reports of data were reviewed. Amitrole has been classified as a substance that is a probable human carcinogen or is reasonably anticipated to cause cancer in humans, according to the US Environmental Protection Agency (US EPA) and the United States National Toxicology Program (US NTP), respectively. It has also been classified by the European Commission as suspected or presumed reproductive toxicant.
  • There were limited substance-specific human health effects data for NaDCC and hexa(methoxymethyl)melamine, therefore, a comparative approach using similar chemicals, called read-across, was used for assessing potential health effects.
  • Using data available for a related substance, effects on the urinary tract and heart in laboratory studies were considered to be the “critical” or important effects used in the assessment of NaDCC.
  • For hexa(methoxymethyl)melamine, using data available for a related substance, effects on the bladder and urinary system in laboratory studies were considered the “critical” or important effects, and potential carcinogenicity.
  • According to information considered under the Ecological Risk Classification of Organic Substances Approach, amitrole and hexa(methoxymethyl)melamine were identified as having a low ecological hazard potential, while NaDCC was identified as having a high ecological hazard potential based on the potential ecotoxicity of this substance. 

Risk assessment outcomes

  • Based upon a comparison of current levels to which Canadians may be exposed and the levels associated with health effects, along with the consideration of international assessments, the risk to human health from these 3 substances is considered to be low.
  • Based upon the outcome of the Ecological Risk Classification of Organic Substances Approach, these 3 substances are considered unlikely to cause ecological harm.
  • The Government of Canada published the Draft Screening Assessment for Triazines and Triazole Group on April 13, 2019. This publication has a 60-day public comment period ending on June 12, 2019.

Proposed screening assessment conclusions

  • As a result of this assessment, the Government is proposing that these 3 substances are not harmful to human health at current levels of exposure.
  • The Government is also proposing that these 3 substances are not entering the environment at levels that are harmful to the environment.

Preventive actions and reducing risk

  • Although amitrole and hexa(methoxymethyl)melamine are not considered to be harmful to human health or the environment at current levels of exposure, these 2 substances are considered to have health effects of concern to humans. Therefore, there may be a potential risk for human health if exposures to either of these 2 substances were to increase or if commercial use patterns of either substance were to change.
  • For these reasons, follow-up activities to track changes in exposure and/or commercial use patterns for amitrole and hexa(methoxymethyl)melamine are being considered.
  • Stakeholders are encouraged to provide any information pertaining to these 2 substances that may help inform the choice of follow-up activity, during the 60-day public comment period on the assessment. This could include information on new or planned import, manufacture or use of the substance.

Related information

  • Pesticidal uses of amitrole have been re-evaluated under the Pest Control Products Act by Health Canada’s PMRA. Pesticidal uses of amitrole, except for its use in spruce bareroot nursery stock (seedbeds), are phased out.
  • Substances in the Triazines and Triazole Group may be found in products available to consumers. Canadians should follow any safety warnings and directions on product labels and dispose of products responsibly.
  • Visit Healthy Home for more information on chemical safety in and around the home.
  • Canadians who may be exposed to these 3 substances in the workplace should consult with their employer and an occupational health and safety (OHS) representative about safe handling practices, applicable laws, and requirements under OHS legislation and the Workplace Hazardous Materials Information System (WHMIS)
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