|
(43-06) Performance Criteria for Test Species Used in Acute and Definitive Terrestrial Plant Toxicity Tests. Stephenson, Gladys*,1, Feisthauer, Natalie1, Miller, Jennifer2, Scroggins, Rick3, 1 ESG International Inc., Guelph, ON2 Miller Environmental Sciences Inc, Innisfil, ON3 Environment Canada, Ottawa, ON ABSTRACT- Acute screening and definitive or chronic toxicity test methods prescribing the use of a battery of terrestrial plant species are currently being developed by Environment Canada for assessment of contaminated site soils and control soils amended with test substances (e.g., chemicals, solvents, pesticides, metal compounds, biosolid materials, de-watered dredged materials destined for disposal on land, etc.). In order to assess the validity or acceptability of the test, performance criteria were developed for each binary combination of six recommended test species and three or four types of soil. The performance criteria apply to the test organisms exposed to the soils comprising the experimental control. In most cases, the experimental control is either a standard formulated soil or a field-collected, natural soil with defined physico-chemical characteristics and properties. The soils in the control treatment are essentially free from the influence of the contamination or contaminants being assessed. The performance of the plants grown in the soils of the control treatment is assumed to be optimal for conditions specified in the test and it is used to describe the exposure concentration-response relationship of the plants exposed to test soils. Therefore, it is important to have a priori reliable and accurate information concerning the emergence and growth characteristics of the test species. A number of toxicity tests were performed from 1996 to 2001 with the six recommended test species. For most of the tests, there were seven measurement endpoints: seedling emergence, root and shoot length and root and shoot wet and dry mass. The acute and definitive data for each type of soil and species were evaluated to determine the mean and standard deviation for each endpoint and the associated coefficient of variation. This information was used to establish performance criteria for the test species recommended for use in the biological test methods. Key words: toxicity test, performance criteria, measurement endpoints, acute and chronic |
