Scope of Assessment

Owing to the chemical nature of DNOC, it readily forms water-soluble sodium, potassium and ammonium salts, and virtually 100% of dissolved DNOC will be in the ionized form at environmentally relevant pHs (pH 6-8). Based on this information, Environment Canada reviewed the use of DNOC salts to determine if they should also be included in this screening assessment. The sodium, potassium and ammonium salts of DNOC are not on the Domestic Substances List (DSL), although DNOC sodium salt is on the Non-Domestic Substances List (NDSL). If a company were intending to manufacture or import these substances, they would be considered to be new to Canada and subject to notification under the New Substances Notification Regulations. Therefore, the ecological screening assessment focused on the uses of DNOC, but a review of the fate and effects of its salts was also carried out.

DNOC used to be registered as a pesticide under the Pest Control Products Act (PCPA); however, its registration was discontinued in December 1990. Three of the DNOC salts (sodium, ammonium and potassium) have been used as pesticides internationally but were never registered under the PCPA in Canada.