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(W/MF155) EROD and genotoxicity induction in Gambusia holbrooki exposed to a pulp mill effluent. Antunes, Sara1, Marques, Catarina1, Santos, Maria1, Pacheco, Mário1, Silva, Paula C.1, Gonçalves, Fernando1, 1 ABSTRACT- Pulp mill effluents are one of the majour sources of river water contamination inducing biochemical and genotoxic effects in several fish species namely Anguilla anguilla (Biochemical and Genotoxic Responses of Adult Eel (Anguilla anguilla L.) to Resin Acids and Pulp Mill Effluent: Laboratory and Field Experiments, Pacheco, M. and Santos, M.A. Ecotoxicology and Environmental Safety 42, 81-93, 1999). EROD (7-ethoxyresorufin O-dethylase) induction must be included among one of the most important biochemical effects induced by pulp mill effluent compounds. The aim of this research work is to compare EROD induction between two Gambusia holbrooki groups (F and L) exposed to a Bleached Kraft Pulp Mill Effluent (BKPME). The group F consisted of individuals collected in the field prior to testing, whereas group L was primarily acclimated to Artificial Pond Water (APW). Water samples collected upstream and downstream from a pulp mill effluent discharge in the Vouga River (Aveiro, Portugal) were used to expose fish according to a previously standard protocol. Individuals from each group were subjected to five different treatments where two were conducted with upstream and three with downstream water, following a decreasing gradient concentration. Laboratory controls were also performed for both groups using APW. Additionally, total body acetylcholinesterase activity (ACh) was assayed to measure the general health condition whereas erythrocytic nuclear anomalies (ENA) were determined in order to identify genotoxicity. Furthermore, all the water samples were submitted to the Microtox® test and the results related to those provided by Ach, ENA, EROD induction assay. Key words: Gambusia holbrooki, bleached kraft pulp mill efluent, genotoxicity, EROD activity |
