Interlaboratory Root Elongation Testing of Toxic Substances on Selected Plant Species

摘要

Four contract laboratories and three EPA laboratories participated in the inter-laboratory testing of 10 toxic substances on a representative plant species from five families. Seeds were germinated on filter paper saturated in a solution of the toxic substance and incubated for 115 hours. The root lengths were measured to evaluate the toxic effects of the chemical concentrations on the various species. The objective of the testing was to estimate the concentration of chemical which reduced root length to 50% of the control length. This research attempts to determine the precision of this bioassay used to evaluate environmental effects under the Toxic Substances Control Act (TSCA). Although the method proved to give a uniform plant growth environment, the species variability in relationship to the chemical concentrations that inhibit root growth makes it difficult to use this assay on more than one species at a time.