New substances: risk assessment summary, new substances notification 18411

Official Title: New Substances Notification No. 18411: Butanedioic acid, 2-methylene-, telomer with sodium phosphinate (1:1), sodium salt, decarboxylated

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 polymer, butanedioic acid, 2-methylene-, telomer with sodium phosphinate (1:1), sodium salt, decarboxylated (Chemical Abstracts Service Registry No. 1663489-58-4), can be classified as a poly(alkyl). The substance does not meet the Reduced Regulatory Requirements criteria according to the New Substances Notification Regulations because the substance contains phosphorus at concentrations above 0.2% by weight.

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 an additive in paints and coatings, and in laundry detergents and household cleaners. Potential uses may include hygiene or personal care products, polymer synthesis applications, oil drilling, agriculture, or water treatment.

Environmental fate and behaviour

Based on its physical and chemical properties, if released to the environment, the substance will tend to partition to water and sediment. The substance is expected to be persistent in water and sediment based on its expected half-lives (>182 days in water, >365 days in sediment). The substance is not expected to bioaccumulate based on its very low octanol-water partition coefficient (logK_ow ≤0). and its high molecular weight will limit its ability to cross biological membranes.

Ecological assessment

Based on the available hazard information on the substance and surrogate data on structurally related chemicals, the substance has low to moderate acute toxicity in algae (median effective concentration (EC₅₀) >1 mg/L) and low acute toxicity in aquatic invertebrates (EC₅₀ >100 mg/L). A predicted no-effect concentration was not calculated for the substance 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 activities is expected to be mainly through the use of the substance in detergents and household cleaners, resulting in the release of the substance to waste-water treatment systems. The anticipated concentration of the substance for use in detergents and cleaners is low (1%), and release from consumer use is expected to be highly dispersed and in low concentrations. Removal through wastewater treatment is expected to be high due to precipitation. Given the low potential for significant environmental exposure, a predicted environmental concentration for notified activities was not estimated. The substance may potentially be used as an intermediate in polymer synthesis applications. Environmental exposure due to potential uses is expected to be similar to that of the notified use.

Based on the low to moderate ecotoxicity, limited bioavailability and high expected removal rate through precipitation from the aquatic environment, 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 is expected to have a low acute toxicity by the oral route (median lethal dose >2000 mg/kg body weight) and a low potential for subchronic toxicity following repeat dermal doses in mammalian test animals (21-day no-observed-effect level >1 mg/dose). The substance does not cause skin sensitization. Structurally similar polycarboxylates exhibit low oral and inhalation toxicity, and minimal skin sensitization. These analogues do not exhibit evidence of genotoxicity, developmental toxicity or reproductive toxicity.

When the substance is used as notified in paints, coatings, laundry detergents and household cleaners, or for potential uses in hygiene or personal care products, direct exposure of the general population is expected to be mainly by direct contact with the skin. Given the high molecular weight of the substance and very low octanol-water partition coefficient (log K_ow ≤0), the substance is not expected to efficiently penetrate the skin barrier. Therefore, systemic uptake of the substance via dermal contact is not anticipated. Direct exposure of the general population from other potential uses, such as in oil drilling, agriculture, or water treatment, is not expected due to the industrial nature of these uses. Indirect exposure of the general population from environmental media such as drinking water is expected to be low.

Based on the low toxicity, low potential for dermal uptake and low potential for indirect exposure of the general population, 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 fo