Proposed Adoption of the Interim Canadian Water Quality Guideline for Diisopropanolamine (DIPA) as an Interim Provincial Water Quality Objective

This notice was originally posted in the old Environmental Registry under number PA05E0001.

Description of policy

The Interim Canadian Water Quality Guideline (CWQG) for the Protection of Aquatic Life for Diisopropanolamine (DIPA) was approved for publication by the Environmental Protection and Planning Committee in June 2005 and will be published by the Canadian Council of Ministers of the Environment (CCME) in the fall of 2005. Available information on the physical-chemical properties, aquatic toxicity, and environmental persistence were considered in developing the guidelines.

DIPA has been identified as a chemical of environmental concern due to its toxicity and widespread industrial use. DIPA applications include cosmetics and personal care products, gas treating, detergents, metalworking fluids, coatings, corrosion inhibitors, and cement applications. In North America, Dow Chemical Company is the dominant DIPA producer and US production was estimated at 7 000 tons per year.

DIPA is very soluble in water and it has a low volatility. It can become strongly sorbed to clay minerals in soil. Studies have shown that DIPA is biodegraded in aerobic conditions by microorganism from a variety of DIPA-contaminated environmental samples. DIPA has been shown to accumulate in plants in contaminated wetlands. Estimates of the acute toxicity of DIPA to freshwater fish range from 788-7698 milligrams per litre, and for invertebrates range from 289-1128 milligrams per litre. There were no chronic studies available in the literature for freshwater fish. Lowest Observable Effect Concentrations (LOECs) represent the lowest concentration used in an experiment where there was a statistically different result compared to the control study (e.g. no chemical used). The 7-day LOEC for invertebrates ranged from 31-250 milligrams per litre. The 72 hour LOEC for algae was 16 milligrams per litre. The species most sensitive to DIPA was an algae, Selenastrum capricornutum.

There is no current Provincial Water Quality Objective for DIPA. The Interim Canadian Water Quality Guideline for DIPA is derived from toxicity data according to the CCME water quality guideline development protocol which is consistent with Ontario's Water Quality Objective Development Process. The proposed Interim Provincial Water Quality Objective (iPWQO) for DIPA is 1.6 milligrams per litre. It was developed by selecting the lowest measurable chronic study and applying a 10-fold safety factor.

Provincial Water Quality Objectives (PWQOs) are maximum desirable concentrations of chemicals which ensure that surface waters are satisfactory for aquatic life and recreation. They are developed with a margin of safety to protect the most sensitive aquatic life-stage of an organism for an indefinite exposure. Technical feasibility and economics are not considered during the standard development, but are considered on a case-by-case basis in the Ministry's approval process for individual discharges. Most objectives are adopted or developed in partnership through the national Canadian Water Quality Guideline Task Group which reports to the Canadian Council of Ministers of the Environment (CCME), however, PWQOs may be developed by the Ontario Ministry of the Environment if there is a provincial need.

Contaminants that impair the aquatic environment are an important environmental concern. Provincial Water Quality Objectives are used to assist in managing these contaminants. The policies and procedures which govern their uses are contained in the booklet - Water Management (1994) - which deals with all aspects of Ontario's water management policy. PWQOs are used to:

1. classify receiving waters for water management purposes;
2. assess contaminant discharges to the aquatic environment;
3. derive water quality-based effluent limits which may be included in Certificates of Approval which are issued to regulate effluent discharges. PWQOs are not the only consideration in controlling discharges.

Purpose of policy:

The Ministry is proposing to add a surface water quality standard for DIPA through adoption of the approved Canadian Council of Ministers in the Environment (CCMEiPWQO).