The Effects of the Pollutant Perfluorooctanesulfonic acid on Anxiety-like Behaviour in Zebrafish

Abstract

Perfluorooctanesulfonic acid (PFOS) is a widespread organic pollutant found in aquatic ecosystems. Zebrafish (Danio rerio) are an important animal model for the investigation of toxic compounds and have been used to study the sub-lethal impact of many toxins. To date, few studies have looked at the behavioural impacts of PFOS in zebrafish, and those that have only examined locomotion, found zebrafish exposed to PFOS have an increase in average swimming speed. In order to examine the effects of PFOS on anxiety-like behaviour in zebrafish, we administered single doses of 0.1 or 1.0mg/L and looked at the behavioural impacts either 20 or 40 days after. Anxiety-like behaviour was measured using a novel tank diving test which involves placing a fish in a tall but deep rectangular area. Time spent in the top, middle, and bottom zone were measured with a motion-tracking software. Previous studies have shown that more time spent in the top zone indicates an anxiolytic effect whereas fish that spend more time spent in the bottom zone indicates an anxiogenic effect. We found that after 40 days, zebrafish exposed to 1.0mg/L spent less time in the bottom zone of the tank and more time in the top zone compared to the control, indicating a decrease in anxiety. This study demonstrates that long exposures to PFOS can have detrimental results in zebrafish which has implications for aquatic ecosystems.

Faculty Mentor: Trevor Hamilton

Department: Psychology (Honours)