T11 AM Aquatic Plants: Methods, Mechanisms and Markers
Tuesday, 15 November 2005: 8:00 AM - 11:40 AM in 343-344

(ROS-1117-841648) Why is Aquatic Macrophyte Toxicity Testing Important?

Roshon, R.¹, ¹ Stantec Consulting Ltd., Guelph, ON, Canada

ABSTRACT- Rooted aquatic macrophytes are an important ecosystem component, but are not required for regulatory testing. Several toxicity tests with rooted aquatic macrophytes have been published with ASTM (E-1841 and E-1913). These test methods can be used to determine the toxicity of pesticides, metals, and organic chemicals to non-target aquatic plants, including Oryza sativa, and Myriophyllum sibiricum. There are advantages and disadvantages of these toxicity tests, as compared to the currently accepted Lemna, algae, fish and invertebrate tests. The most obvious drawback is the additional infrastructure and cost associated with the rooted aquatic macrophyte testing, as compared with the simpler fish and invertebrate toxicity studies. Toxicity tests with aquatic macrophytes are replicable and repeatable systems. Features of these toxicity tests that enhance standardization include a chemically defined nutrient solution and an artificial rooting substrate. Due to their ecological relevance and sensitivity, these partial life cycle laboratory toxicity tests would be a beneficial addition to the regulatory data set.

Key words: macrophytes, Myriophyllum sibiricum, pesticide, toxicity