WP17 Chemical Hazard Identification, Classification and Communication
Wednesday, 16 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(OKO-1117-824345) Progress on the Ecological Categorization of UVCBs on the Domestic Substances List.

Okonski, A.¹, Lin, M.², Schnabel, S.³, MacDonald, D.⁴, Robinson, P.⁵, Morin, D.⁶, Costa, P.⁷, Eggleton, M.⁸, ¹ Environment Canada, Gatineau (Hull), QC, CANADA² Environment Canada, Gatineau (Hull), QC, CANADA³ Environment Canada, Gatineau (Hull), QC, CANADA⁴ Environment Canada, Gatineau (Hull), QC, CANADA⁵ Environment Canada, Gatineau (Hull), QC, CANADA⁶ Environment Canada, Gatineau (Hull), QC, CANADA⁷ Environment Canada, Gatineau (Hull), QC, CANADA⁸ Environment Canada, Gatineau (Hull), QC, CANADA

ABSTRACT- The DSL consists of approximately 23,000 substances that were in Canadian commerce during 1984-1986. Around 4400 substances are represented by UVCBs (Unknown or Variable Composition, Complex Reaction Products, and Biological Materials). According to CEPA 1999, all the DSL substances must be categorized by September 2006. Environment Canada developed a strategic approach for UVCB ecological categorization. First, UVCBs were sorted into six major streams: organics, organometallics, organic metal salts, inorganics, polymers, and biologicals. Since approaches for the ecological categorization of non-UVCB discrete organics, organometallics, inorganics, and other chemicals have already been developed, they are being implemented to categorize UVCBs that fall into these groups. Using a qualitative approach based on readily available information and expert judgment, UVCBs were further separated into two major categories: 1) low ecotoxicological concern (850 substances); 2) under review for PBiT (persistence, bioaccumulation, and aquatic toxicity). The second category represents UVCBs which require further considerations. Experimental information was used to identify pivotal values for iT, P, and B for 296, 175, and 33 UVCBs, respectively. The critical review of all these studies is continuing. In addition, attempts to derive representative molecular structures for some UVCBs were undertaken, and modeled data were produced for around 800 substances. Category approaches were also developed by Environment Canada to identify small groups of substances with similar structures and physico-chemical properties, where the ecotoxicity and environmental fate of the substances within such sub-groups would be assumed to be relatively similar. Therefore, when data are available for some of the substances from the sub-group, they are used to categorize the whole sub-group. To date, Environment Canada made categorization decisions for 1400 UVCBs, for which PBiT profiles were required, and work is on-going on the others.

Key words: ecological categorization, Domestic Substances List, UVCBs