Canadian Sediment Quality Guidelines (CSeQGs)

Overview

The Canadian Sediment Quality Guidelines for the Protection of Aquatic Life (CSeQGs) protect aquatic organisms that live in or on the sediment that forms on the bottom of lakes and rivers. Good quality sediment provides habitat and food for aquatic life. Many toxic chemicals entering lakes and rivers end up in the sediment. Some of these substances may leave the sediment, returning to the water or entering the food web.

Development of Canadian Sediment Quality Guidelines began in 1990.

Procedures for Guideline Development (Protocol)

The procedures used in deriving Canadian Sediment Quality Guidelines for the Protection of Aquatic Life are described in the document entitled Protocol for the Derivation of Canadian Sediment Quality Guidelines for the Protection of Aquatic Life. This protocol is intended to produce tools that will be broadly protective and will support the functioning of healthy ecosystems (Gaudet et al. 1995; Smith et al. 1996a,b).

The Sediment Quality Guideline Protocol relies on both the modified National Status and Trends Program approach and the Spiked-Sediment Toxicity Test approach. Together these two approaches provide complementary information to support the development of national Sediment Quality Guidelines (MacDonald et al. 1992; CCME 1995). The modified National Status and Trends Program approach relies on field data that demonstrates associations between chemicals and biological effects. The Spiked-Sediment Toxicity Test approach establishes cause-effect relationships. Spiked-sediment toxicity data are currently available for only a few substances such as cadmium, copper, fluoranthene, and pyrene. Therefore, the threshold effect levels calculated using the modified National Status and Trends Program approach are most likely to be adopted as interim Sediment Quality Guidelines. The probable effect levels, also calculated using this approach, provide additional information regarding the potential for observing adverse biological effects at higher concentrations.

Application of Guidelines

CSeQGs and probable effect levels are flexible interpretive tools for evaluating the toxicological significance of sediment chemistry data, as well as for prioritizing actions and management decisions. Sediment chemical concentrations below the Sediment Quality Guidelines are not expected to be associated with any adverse biological effects; however, concentrations above the probable effect levels are expected to be frequently associated with adverse biological effects. Chemical concentrations between the Sediment Quality Guidelines and probable effect levels represent the range in which effects are occasionally observed. The use of these two values is a practical means of characterizing sites as being of minimal, potential, or significant toxicological concern in order to focus further investigations.

The Guidelines should not be regarded as blanket values for national sediment quality. Variations in environmental conditions across Canada will affect sediment quality in different ways and many of the guidelines may need to be modified according to local conditions such as assimilative capacity, sensitivity of endangered species and habitat. Site-specific sediment quality objectives are established to reflect the local environment and may be adopted by a jurisdiction into legislation to become standards. Where water bodies are of exceptional quality, or where they support valuable biological resources (e.g., endangered species), it is the policy of the CCME that degradation of the existing sediment quality to the guideline value should always be avoided. Similarly, modifications of guidelines to site-specific objectives should not be made on the basis of aquatic ecosystem characteristics that have arisen as a direct result of previous human activities.

The use of CSeQGs for site-specific sediment quality objectives requires an understanding of the chemical, physical, and biological characteristics of the water body and an understanding of the behaviour of a substance once it is introduced into the aquatic environment. Factors affecting the application of the guidelines include:

• the general characteristics of lakes, ponds, and rivers;
• the effect of local environmental conditions on sediment quality;
• processes influencing the concentration of parameters in sediment; and,
• factors that modify toxicity to aquatic organisms.

Products Available

Protocol

The Protocol of the Canadian Sediment Quality Guidelines is available in HTML and PDF format. You need Adobe® Acrobat® Reader to view and print the PDF file. If you do not already have Acrobat® Reader, you may download it at no charge.

• Protocol for the Derivation of Canadian Sediment Quality Guidelines for the Protection of Aquatic Life (HTML) (PDF)