Prolonged phenanthrene exposure reduces cardiac function but fails to mount a significant oxidative stress response in the signal crayfish (Pacifastacus leniusculus).

Click for Abstract : Crustaceans are important ecosystem bio-indicators but their response to pollutants such as polyaromatic hydrocarbons (PAHs) remains understudied, particularly in freshwater habitats. Here we investigated the effect of�phenanthrene�(at 0.5, 1.0 and 1.5�mg�L?1), a 3-ringed PAH associated with petroleum-based aquatic pollution on survival, in�vivo and in situ cardiac performance, the�oxidative stress�response and the tissue burden in the signal crayfish (Pacifastacus leniusculus). Non-invasive sensors were used to monitor heart rate during exposure. Phenanthrene reduced maximum attainable heart rate in the latter half (days 8�15) of the exposure period but had no impact on routine heart rate. At the end of the 15-day exposure period, the electrical activity of the semi-isolated in situ crayfish heart was assessed and significant�prolongation�of the QT interval of the�electrocardiogram�was observed. Enzyme pathways associated with oxidative stress (superoxide dismutase and total oxyradical scavenging capacity) were also assessed after 15 days of phenanthrene exposure in gill, hepatopancreas and skeletal muscle; the results suggest limited induction of protective antioxidant pathways. Lastly, we report that 15 days exposure caused a dose-dependent increase in phenanthrene in hepatopancreas and heart tissues which was associated with reduced survivability. To our knowledge, this study is the first to provide such a thorough understanding of the impact of phenanthrene on a crustacean.