TP1 Non-Point Source Pollution and TMDLs
Tuesday, 15 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(MOO-1117-827855) A Methodology for Derivation of Ideal Performance Standards for Pesticides in Canada.

Moore, D¹, Teed, R¹, Thompson, R¹, Breton, R¹, Willis, R², Jiapizian, P³, Caux, P³, Bauder, M³, Bacchus, P³, ¹ Cantox Environmental, Inc., Ottawa, Ontario, Canada² Cantox Environmental, Inc., Halifax, Nova Scotia, Canada³ National Guidelines and Standards Office, Environment Canada, Gatineau, Quebec, Canada

ABSTRACT- A goal of the Canadian Agricultural Policy Framework is to develop non-regulatory standards that specify desired environmental quality required of agriculture. As such, Ideal Performance Standards (IPS) are being developed for pesticides in Canada. IPS are standards that protect biota in receiving environments affected by agricultural operations. The purpose of this presentation is to describe the methodology for deriving IPS for pesticides in surface water. The goal for IPS is protection of at least 95% of aquatic species in the water body of interest. Impacts on 5% or less of aquatic species generally are ecologically tolerable due to the functional redundancy of ecosystems. Exceptions to this general protection goal may be required to protect rare, commercially or recreationally important, or other important species. In the methodology, decision criteria are used to select from six methods. The method selected depends on the available data. The methods include: (1) watershed-defined, (2) site-specific species sensitivity distribution (SSD), (3) generic SSD, (4) full Canadian water quality guideline (CWQG), (5) interim CWQG, or (6) other approved benchmark. The watershed-defined method derives IPS for a specific watershed. Such IPS may be intended to protect locally-significant or sensitive species. The site-specific SSD and generic SSD methods are based on the SSD approach and estimate the concentration of a pesticide in water that will be protective of 95% of aquatic biota. The availability of site-specific data will determine the option selected. If data are insufficient for the SSD methods, the IPS can be an existing full or interim national Canadian water quality guideline. The last method is to select a benchmark from another jurisdiction. The IPS framework is also used to estimate maximum loads to the water body, and ultimately to maximum releases from individual farms. These methods and a case study will be described and included in the presentation.

Key words: standard, pesticide, water quality, agriculture