Wood preservation facilities, general recommendations: chapter A-3


3. Environmental Effects

This section provides references to the guidelines and requirements for water quality, air and soil quality that the users of wood preservatives should be aware of.

Wood preservatives may be delivered in various forms including ready to use mixture or in separate solutions that will require mixing at the wood preservation facility. Therefore, it is important to document and be aware of potential environmental effects of these individual solutions as they are handled at different concentrations and/or states. The breakdown products should also be known and assessed for environmental effects as they can potentially be more toxic to the environment than the parent compound.

3.1 Aquatic Toxicity

Users of wood preservatives should know that Environment Canada is responsible for the administration and enforcement of the pollution prevention provisions (section 36) of the Fisheries Act, which prohibits the deposit of deleterious substances in water frequented by fish unless the deposit is authorized by regulation under the Act. Operators of wood treatment facilities should note that the use of an approved chemical, even in accordance with the label, should not result in a contravention of Section 36(3) of the Fisheries Act ("no person shall deposit or permit the deposit of a deleterious substance of any type in water frequented by fish or in any place under any conditions where the deleterious substances or any other deleterious substance that results from the deposit of the deleterious substance may enter any such water"). Any discharge which results in the release of a deleterious substance in water frequented by fish must be reported and corrective measures taken. In the event of a discharge of deleterious substances in fish bearing water, the general prohibition in subsection 36(3) of the Fisheries Act would apply.

For most wood preservatives, there are regulatory guidelines or objectives for the constituents of the preservative in the natural environment. Regulatory guidelines or objectives are developed by various federal and provincial departments and agencies. The users of wood preservatives should document and be aware of these regulatory guidelines or objectives.

The following provides a list of references that provide users with specific limits, objectives and benchmarks:

Additional resources include:

Depending on local requirements, the location, the facility may be required to comply with specific water quality guidelines or objectives for specific purposes (e.g. drinking water quality objectives, national water quality guidelines, cross-jurisdictional commitment and etc.) Although the Canadian Water Quality Guidelines are broadly applied and measured to assess and manage water quality in Canada, these guidelines should not be regarded as blanket values for national environmental quality (4). Variations in environmental conditions such as natural background concentration, site-specific aquatic conditions and sensitivity of receptor species in the local area have the potential to influence the applicability of these water quality guidelines across the country. Therefore, it may be necessary to establish site-specific limits that account for local environmental conditions.

A site-specific threshold concentration of a specific chemical can be established by conducting toxicity testing that incorporates the conditions of the receiving environment (see 3.1.1) or it can be based from previous studies in the literature if the test conditions are similar to the local site.

In addition, most provinces and some municipalities may have additional objectives or guidelines that may differ from the national guidelines and objectives to account for the specific environmental conditions in their respective jurisdiction. Users of wood preservatives should check with their respective jurisdictions for additional guidance.

Table 3 can be used to summarize the local regulatory requirements and objectives to preserve aquatic quality in natural water bodies.”

3.1.1 Site & component-specific toxicity

As mentioned above, site-specific limits may be necessary to establish for local environmental conditions when existing guidelines and objectives are not applicable. It might also be necessary to develop local limits when a potentially toxic pesticide component has no regulatory limit established. The toxicity test methodology used must be recognised by federal and provincial authorities in order to be acceptable by the authorities. Environment Canada has a series of biological test methods and guidance documents

The American Public Health Association has water testing and monitoring methods in the Standard Methods for the Examination of Water and Wastewater that are commonly used by the industry

The American Society for Testing and Materials (ASTM) also has methods that may be suitable for a specific aquatic toxicity test.

The Organisation for Economic Co-operation and Development (OECD), has testing methods of chemicals and principles of good laboratory practice.

The International Organization for Standardization (ISO) has developed voluntary International Standards that give state of the art specifications for products, services and good practice including testing methodology.

Such testing can be appropriately developed with the help of a specialised local laboratory. The laboratory should be an accredited facility of the Canadian Association for Laboratory Accreditation Inc.(CALA).

Environment Canada recommends conducting acute lethality testing (to determine if a discharge is deleterious to fish in bearing water) on representative organisms of the food chain, namely fish (secondary consumer) and invertebrates (primary consumer).

Most commonly used species for performing acute lethality testing are:

  • Fish
    • Rainbow trout (Oncorhynchus mykiss, formerly named Salmo gairdneri)
    • Fathead minnows (Pimephales promelas)
    • Threespine Stickleback (Gasterosteus aculeatus)
  • Invertebrate :
    • Daphnids (Daphnia magna and/or D. pulex)
    • Benthic invertebrate

Most of the standardized methods used to perform toxicity tests describe general or universal conditions and procedures using a variety of test materials. Additional conditions and procedures are stipulated which are specific for assessing samples of chemicals, effluents, elutriates, leachates, or receiving waters.

Additional sublethal test methods on a plant or algae (primary producers) are available on the mentioned above Environment Canada website to determine chronic lethality effects.

Table 3.1 is an example of a template table to summarize results of acute toxicity tests

3.2 Air Pollution

Airborne pollution from wood preservation facilities is usually specific to some process within the plant and is rarely an issue outside the facility. Air pollution from wood preservative facilities can be generated as vapour/gas, aerosols and/or contaminated dust. Section 4 addresses the potential health effects of exposure and Section 5 addresses the potential air emissions.

As mentioned in Section 7 on design recommendations, interior tanks should be vented to the exterior or into a dedicated overflow tank and then to the exterior. There should never be any venting directly into the workplace.

When working with vaporous pesticides solutions it is recommended to channel all vents to an air pollutant control device like a scrubber to ensure that air quality respect the limits prescribes by the local authorities.

3.3 Soil Contamination

Soil contamination could potentially be an area of major concern if no effective mitigation measures are in place. Contaminated soil could contaminate nearby water bodies and drinking water sources due to runoff and can be spread by vehicular traffic and wind. Sections 7 and 8 present the design and operational recommendations to minimize soil contamination.

The Canadian Environment Quality Guidelines published by CCME contains specific guidelines on soil quality for the protection of environmental and human health, guidance on contaminated site-related activities and developing and maintaining the Canada-wide Standard for Petroleum Hydrocarbons in soil and the requirements under it.

EC has standardized soil toxicity tests for soil invertebrates (springtails and earthworms) and plants available.

Soil contamination can take place over a long period of operation by accumulation and also from spills events. Spills are defined and are usually easily contained. Small inputs of contaminants distributed on a large area over a long period of time are very hard to contain and to treat. Without proper design equipment and proper operational procedures, risks of bioaccumulation of contaminants are greater. During major storm events or freshet, washout rain can create erosion and expose potential contaminated sediments from lower levels and transport them downstream into waterbodies or into underground water sources. A good environmental monitoring program is a recommended solution to detect areas of small contamination. With proper preventive and corrective actions, it is possible to avoid potential accumulation of soil contaminant.

In addition, most provinces have additional objectives or guidelines that may differ from the national guidelines and objectives to account for the specific environmental conditions in their respective provinces. Users of wood preservatives should check with their respective provinces for additional guidance.

To learn more on Environmental Monitoring, see Section 10 of this Chapter.

3.4 Reporting to Environmental Programs

Wood preservation facilities may be required to report to the National Pollutant Release Inventory (NPRI) of Environment Canada or other provincial reporting program if the facilities meet the reporting thresholds. NPRI was established under the Canadian Environmental Protection Act, 1999 to collect data on substances of concern in Canada. Certain type of activities conducted in the wood preservation facilities may trigger specific reporting requirements. For example, wood preservation using pentachlorophenol is required to report on Part 3 substances under NPRI.

To confirm whether submission of an NPRI report to EC will be required, the proponent should contact the NPRI office at 1-877-877-8375 or inrp-npri@ec.gc.ca.

For the latest reporting thresholds and requirements, please consult the NPRI website.

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