(PT218) Effect of salinity to exposure and toxicity of chemically dispersed crude oil.
Ramachandran, S1, Hodson, P1, King, T2, Lee, K2, 1 Queens University, Kingston, Ontario, Canada2 COOGER-CREPGE, Halifax, Nova Scotia, Canada
ABSTRACT- Chemical dispersants are known to increase the toxicity of crude oil by increasing the miscibility of the toxic components. One of the more researched components of crude oil that is embryotoxic as well as dispersible are polycyclic aromatic hydrocarbons (PAHs). Earlier studies on EROD induction in rainbow trout have demonstrated that chemical dispersion increases exposure to PAHs by increasing the concentrations of hydrocarbons in solution or suspension of oil droplets. PAHs have also been identified in causing embryo-larval deformities in Pacific herring and pink salmon. The first part of the study was designed to investigate the effect of salinity on exposure to PAHs from chemically dispersed oil by conducting exposures to freshwater, brackish water and salt-water species. The second part of the study focused on the toxicity to embryo-larval stages in freshwater medaka and brackishwater mummichogs exposed to chemically dispersed crude oil. The toxicity assay also attempted to determine whether any of the developmental stages are particularly sensitive to insult from crude oil contaminants. Preliminary results from freshwater exposure indicate a 1000 fold increase in exposure to PAHs from chemically dispersed oil for juvenile trout and 50 fold greater toxicity effects for medaka embryos. The 2nd to 5th day stage of development for medaka embryos was noticeably more sensitive to crude oil exposures then the rest.
Key words: embryolarval, dispersed crude oil, salinity