Canada Consults on Ecological Risks of Organic Compounds

The Canadian government is consulting on a science approach document for the ecological risk assessment of organic compounds.

The document ranks 640 substances for their potential to cause ecological harm, using three levels of concern.

All are from the third phase of the country's Chemicals Management Plan (CMP) and are specified on the Domestic Substances List.

The substances are currently undergoing a public consultation and will undergo screening assessments.

Those substances of higher health or environmental concern will go on for further assessment.

The ecological risk classification used data and models to identify substances warranting further evaluation, and to describe hazard or potency parameters used, including:

> mode of action;

> chemical reactivity;

> internal toxicity thresholds; and

> bioavailability.

Potential exposure of organisms in aquatic and terrestrial environments was characterised based on:

> emission rates;

> persistence; and

> long-range transport in air.

Substances were assigned to low, moderate or high groups of potential ecological concern based on hazard and exposure classifications. Accordingly:

> 40 substances were classified in the high category;

> 92 as moderate; and

> 508 substances as low.

Those of in the high group will undergo further assessment. Fifty eight of the moderate substances were judged to have similarities to those in the high group and will also undergo further assessment. The remaining 542 substances are not expected to pose an ecological risk on current information.