Bioconcentration of phenanthrene and metabolites in bile and behavioral alterations in the tropical estuarine guppy Poecilia vivipara
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Quantification of polycyclic aromatic hydrocarbon (PAH) metabolites in fish bile is widely used to evaluate levels of internal PAH contamination in fish, whereas behavioral effects are deemed important to address potential risks to fish populations. The estuarine guppy Poecilia vivipara was exposed for 96h to waterborne phenanthrene at concentrations of 10, 50, 200 and 500μgL(-1). Phenanthrene and metabolites in bile were analyzed by fixed fluorescence at 260/380nm (excitation/emission) wavelengths. Phenanthrene increased in the bile of exposed fish in a dose-dependent pattern, and log bile bioconcentration factors ranged from 4.3 to 3.9 at 10 and 500μgL(-1) phenanthrene, respectively, values that are similar to predicted bioconcentration factors based on phenanthrene Kow. Swimming resistance index was reduced to 81% of control values at 500μgL(-1). Alteration of swimming speed was non monotonic, with a significant speed increase relative to control fish in treatments 50 and 200μgL(-1) phenanthrene, respectively, followed by a speed decrease in fish exposed to 500μgL(-1). However, swimming trajectories of fish exposed to 50, 200 and 500μgL(-1) was altered by the development of a repetitive circular swimming behavior, in contrast to the controls that explored the entire experimental arena. This change in swimming patterns apparently explains the reduction in prey capture rates at 200μgL(-1) phenanthrene. This study provides important information enabling the use of the estuarine guppy P. vivipara to monitor PAH metabolites in bile and its bioconcentration, linking internal exposure with ecologically relevant behavioral effects in the species.