New substances: risk assessment summary, new substances notification 18431

Official title: New Substances Notification No. 18431: 2,4-Imidazolidinedione, 1,3-bis(2-hydroxyethyl)-5,5-dimethyl-

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

2,4-Imidazolidinedione, 1,3-bis(2-hydroxyethyl)-5,5-dimethyl- (Chemical Abstracts Service Registry No. 26850-24-8) is a chemical that can be classified as a carbonyl urea.

Notified and potential activities

The substance is proposed to be manufactured in and/or imported into Canada in quantities greater than 10 000 kg/yr for use as a component of inkjet printing inks in personal and commercial/industrial applications. Potential uses may include a variety of applications, such as personal care products.

Environmental fate and behaviour

Based on its physical and chemical properties, if released to the environment, the substance will tend to partition to water. The substance is expected to be persistent in water based on its half-life (>180 days) and resistance to biodegradation. The substance is not expected to bioaccumulate based on its low predicted bioconcentration and bioaccumulation factors (<250 L/kg).

Ecological assessment

Based on the available hazard information on the substance and surrogate data on structurally related chemicals, the substance has low acute toxicity in fish, aquatic invertebrates and algae (median lethal concentration (LC₅₀) and median effective concentration > 100 mg/L). A predicted no-effect concentration was not calculated given the low potential for ecological risk.

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 limited, as during transport the cartridges containing the substances are sealed until use and returned to the manufacturer when spent, and during use the substance is bound into the ink and would not be expected to be released. A predicted environmental concentration (PEC) for notified activities was not calculated given the low potential for exposure and low ecotoxicity.

The substance has a wide variety of potential uses, some of which could result in higher concentrations of the substance in Canada than the notified use. However, given the low toxicity of the substance, environmental release from potential uses is considered to be of low concern. The PEC for potential uses was not calculated given the low potential for ecological effects.

Based on the low ecotoxicity, the substance is unlikely to cause ecological harm in Canada.

Human health assessment

Based on the available hazard information and surrogate data on structurally related chemicals, the substance has a low potential for acute toxicity by the oral, dermal and inhalation routes of exposure (oral and dermal median lethal dose >2000 mg/kg body weight; inhalation LC₅₀ >5 mg/L/4hr) and a low potential for subchronic and reproductive/developmental toxicity following repeat oral doses in mammalian test animals (90-day no-observed-adverse-effect level >100 mg/kg bw/d). It is a non-sensitizer and not mutagenic in vitro. Therefore, the substance is unlikely to cause genetic damage.

When the notified substance is used as a component of inkjet printing inks for personal and commercial/industrial applications, direct exposure of the general population is expected to be mainly by contact with the skin or by inhalation at low levels given that handling of ink cartridges is expected to be infrequent and brief, and once the ink is set on paper exposure is expected to be low. Indirect exposure of the general population from environmental media such as drinking water is expected to be low. When the notified substance is used in its potential uses in personal care products, direct exposure of the general population is expected to be mainly by contact with the skin at moderate to high levels; however, the high water solubility (>10 000 mg/L) and very low octanol-water partition coefficient (logK_ow <0) would limit dermal absorption.

Based on the low potential for acute and subchronic toxicity, 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.

Assessment conclusion

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

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 workplace use.