Risk Assessment of the Oryzias Latipes Embryos Exposed to Polycyclic Aromatic Hydrocarbons

Context/Purpose : The purpose of this study was to evaluate the toxicity of Polycyclic Aromatic Hydrocarbons (PAHs) to the embryos of Oryzias latipes, and to investigate the effect of PAHs on O. latipes.

Methods: After hatching the embryos of O. latipes for 21 days in the test solution, the hatchability was confirmed. The extent to which PAHs affect embryo hatching was calculated using the TolCalc 5.0 program. The median effective concentration (EC50) was calculated by the Trimmed Spearman-Karber method, depending on the egg hatching rate. Based on the relationship between n-Octanol / Water Partition Coefficient (logKow) and EC50, we can confirm the correlation between PAHs and embryo through Structure-Activity Relationship.

Results: The EC50 concentrations affecting embryo were different for each PAHs. When the correlation between logKow and EC50 was confirmed, the EC50 value tended to decrease as the logKow value increased. The relationship between PAHs and O. latipes embryos was confirmed by the Structure-Activity Relationship. Using optical microscope, we could confirm the effect of PAHs on O. latipes hatched from embryo. Fishes that hatched from embryos affected by PAHs showed symptoms such as blue sac disease (BSD), facial anomalies, abdominal anomalies, and spinal deformities.

Interpretation: As the logKow value increased, the EC50 concentration tended to decrease. As the logKow value increased, the PAHs increased the toxicity affecting the embryo. We confirmed the structure-activity relationship of PAHs by checking the relationship between logKow value and EC50. Observation of the hatching fish using optical microscope confirmed that PAHs not only affect the embryo hatching of O. latipes, but also the life after hatching.

Conclusion: Exposure to a biological directly PAHs was subjected to toxicity assessment accordingly and if the study proceeds in a manner that the modeling based on the toxicity results PAHs can provide a better way to quickly and accurately assess and respond than when exposed to the environment It is thought that it will be used as basic data.