MP8 Current Trends in Toxicity Evaluation
Room 19A/B, Level 4
2:10 PM - 5:30 PM, Monday, 10 November 2003
Chair: Ownby, David ,
Co-chair: Newman, Mike ,
(153) Chronic toxicity of hydrophobic compounds measured using partition controlled delivery.
Turcotte, D1, Akhtar, P1, Kiparissis, Y1, Hodson, P1, Brown, R1, 1 Queen's University, Kingston, Ontario, Canada
ABSTRACT- In conventional static or semi-static embryo toxicity assays with fish, the nominal concentrations of hydrophobic chemicals are often used to establish the toxic thresholds, which often far exceed the solubility limits of test compounds. We have developed a partition controlled delivery (PCD) method that maintains the concentrations of hydrophobic chemicals in test solutions at or below solubility limits for extended exposure times. Polydimethylsiloxane (PDMS) films containing various concentrations of C1-C4 phenanthrenes (PHE) are deposited on the side of 20 ml vials and equilibrated with test media. Fertilized Japanese medaka (Oryzias latipes) eggs are added for a 17-day embryo toxicity test at 26°C. Previous experiments showed the efficacy of the PCD method in comparison with semi-static (24h renewal) embryo-larval toxicity tests. Current results for the series of PHE indicate that for more soluble compounds (e.g. C1-PHE) the two methods give similar effect concentrations, but for less soluble compounds (e.g. C4-PHE) nominal semi-static effect concentrations are above solubility whereas the PCD method effect concentrations are below solubility. These results show that the PCD exposure method is a more sensitive and more realistic method for assessing embryotoxicity of non-polar compounds. Future work will include structure-activity relationships of some PHE derivatives.
Key words: pdms, pah, toxicity, fish