Use of biochemical biomarkers as a screening tool to focus the chemical monitoring of organic pollutants in the Biobio river basin (Chile)

Sediment and water from the Biobio river basin (Central Chile) were used in a simulated field-exposure experiment with juvenile rainbow trout. After two weeks of exposure, brain acetylcholinesterase (ACNE), liver carboxylesterase (CbE) and cytochrome P4501A1 (CYP1A1) activities were measured. Esterase activities did not show significant variations between trout exposed to sediment and water. Sediment was found to contain pollutants that induced CYP1A1 catalytic activity. Chemical analysis of these inducers revealed that PAHs were the main contaminants (mean content of 5,818 ng g-ʹ d.w.) causing measurable effects in biota. This study shows that from an ecotoxicological point of view, it is useful to test certain biochemical biomarkers before monitoring chemicals in the aquatic environment.