New substances: risk assessment summary, new substances notification 20903

Official title: New Substances Notification 20903: Glycols, α,ω, C_2-6, polymers with adipic acid, carbomonocyclepolycarboxylic acid, polymethyl ester, dodecanedioic acid, hydroxypolymethylalkyl hydroxypolymethylalkanoate, isophthalic acid, 1,1'-methylenebis[4-isocyanatobenzene], neopentyl glycol and terephthalic acid (Confidential Accession Number 19583-1)

Regulatory decisions

Under the provisions for Substances and Activities New to Canada in Part 5 of the Canadian Environmental Protection Act, 1999 (CEPA), and pursuant to section 83 of the Act, the Minister of the Environment and the Minister of Health have assessed information in respect of the substance and have determined that it is not anticipated to enter the environment in a quantity or concentration or under conditions that have or may have an immediate or long term harmful effect on the environment or its biological diversity, constitute or may constitute a danger to the environment on which life depends, or constitute or may constitute a danger in Canada to human life or health.

Substance identity

The notified polymer is glycols, α,ω-, C_2-6, polymers with adipic acid, carbomonocyclepolycarboxylic acid, polymethyl ester, dodecanedioic acid, hydroxypolymethylalkyl hydroxypolymethylalkanoate, isophthalic acid, 1,1'-methylenebis[4-isocyanatobenzene], neopentyl glycol and terephthalic acid (Confidential Accession No. 19583-1). The substance does not meet the Reduced Regulatory Requirements criteria according to the New Substances Notification Regulations (Chemicals and Polymers) because it contains isocyanate functional groups.

Notified and potential uses

The substance is proposed to be imported into Canada in quantities greater than 10 000 kg/yr for the notified use in industrial adhesives. Potential uses may include in adhesives or sealants in Do-It-Yourself (DIY) products for consumers.

Environmental fate and behaviour

Based on its physical and chemical properties, if the substance is released to the environment, it will tend to partition to soil and sediment. The substance is expected to be persistent in soil and sediments based on its anticipated low hydrolysis and lack of functional groups susceptible to biodegradation. The substance is not expected to bioaccumulate based on its large molecular structure and high molecular weight, which will limit its ability to cross biological membranes.

Environmental risk assessment

Based on the available hazard information, the substance is expected to have low acute toxicity to fish (median lethal loading rate > 100 mg/L). A predicted no-effect concentration was not calculated given the low potential for hazard to the environment.

The notified and other potential activities in Canada were assessed to estimate the environmental exposure potential of the substance throughout its life cycle. Environmental exposure from the notified activity is expected to be mainly from equipment and transport vessel cleaning by release of the substance to water at low rates. A predicted environmental concentration was not calculated due to the low potential for environmental exposure and ecotoxicity. No potential activities that could significantly increase environmental risks compared to those notified were identified.

Based on the low potential for environmental exposure and ecotoxicity, the substance is unlikely to cause harm to the environment in Canada.

Human health risk assessment

Based on the available hazard information, the substance is expected to have a low acute toxicity by the oral route (median lethal dose > 2000 mg/kg body weight).

When the notified substance is used as an industrial adhesive, the general population may come into contact with end-use products containing the substance; however, exposure will be limited by the high molecular weight of the substance, which will limit absorption through the skin. Furthermore, the substance will be chemically reacted into a stable matrix once the product is cured and will be unavailable for uptake. Indirect exposure of the general population from environmental media is not expected given the specialized industrial use of the substance, which results in little or no release to the environment.

Potential uses of the substance include use in sealant or adhesive DIY products for consumers, where direct exposure is expected to be mainly by contact with the skin. Products containing isocyanates require specific labelling instructions for use to reduce exposure. Exposure will be further limited by the high molecular weight of the substance, which will limit its ability to cross biological membranes, and by the infrequent use of products containing the substance as well as the small amount of product used during application. The substance will be chemically reacted into a stable matrix once the product is cured and will be unavailable for uptake. Indirect exposure of the general population from environmental media is not expected, similar to that of the notified use.

Based on the low potential for exposure, the substance is not likely to pose a significant health risk to the general population, and is therefore unlikely to be harmful to human health.

The assumptions made in the assessment are considered to be adequately protective for the general population as well as for subpopulations who may be more susceptible or highly exposed.

Assessment conclusion

When the substance is used as notified or for other identified potential activities, it is not expected to be harmful to human health or the environment according to the criteria under section 64 of the Act.

A conclusion under CEPA, on this substance, is not relevant to, nor does it preclude an assessment against the hazard criteria for Workplace Hazardous Materials Information System that are specified in the Controlled Products Regulations or the Hazardous Products Regulations for products intended for the workplace.