Item


Antioxidant enzyme activities as biomarkers of Zn pollution in fluvial biofilms

The potential of the antioxidant enzyme catalase (CAT) and ascorbate peroxidase (APX) as molecular biomarkers of Zn toxicity in freshwater biofilms has been explored in this study jointly with other classical functional and structural endpoints (photosynthetic parameters, algal group composition and bioaccumulation). Biofilms were colonized in an indoor microcosm system for 5 weeks and then exposed to Zn for 5 weeks. To evaluate Zn effects, biofilms were sampled 5 and 3 days before exposure, just before exposure (time 0), and after 6h, 1, 3, 7, 21 and 35 days of metal exposure. Most endpoints measured were affected by Zn exposure (320μgZnL -1) during both periods of exposure. APX was the only functional parameter responding after a few hours of Zn exposure, highlighting its use as an early toxicity biomarker. Structural changes began after 3 days of exposure, starting with a decrease in algal biomass and an increase in the OD 430:665 ratio. Structural changes in biofilm communities were observed after 1 week, leading to a shift from diatoms to cyanobacteria and green algae-dominated communities. CAT activity was thereafter enhanced (after three weeks of exposure) and attributed not only to a direct effect of Zn bioaccumulation but also to an indirect effect of the community composition changes driven by chronic metal exposure. It can be concluded that biofilm antioxidant enzyme activities may provide evidence of early stress caused by metal exposure and also provide information about the mechanism of community adaptation. This information can be of great interest to improve current tools used for risk assessment

This study was supported by the Spanish Ministry Project (GCL2006-12785/HID) and grant (FPI20060097171),and the EC Project KEYBIOEFFECTS (MRTN-CT-2006-035695)

© Ecotoxicology and Environmental Safety, 2012, vol. 80, p. 172-178

Elsevier

Author: Bonet Sánchez, Berta
Corcoll i Cornet, Natàlia
Guasch i Padró, Helena
Date: 2012
Abstract: The potential of the antioxidant enzyme catalase (CAT) and ascorbate peroxidase (APX) as molecular biomarkers of Zn toxicity in freshwater biofilms has been explored in this study jointly with other classical functional and structural endpoints (photosynthetic parameters, algal group composition and bioaccumulation). Biofilms were colonized in an indoor microcosm system for 5 weeks and then exposed to Zn for 5 weeks. To evaluate Zn effects, biofilms were sampled 5 and 3 days before exposure, just before exposure (time 0), and after 6h, 1, 3, 7, 21 and 35 days of metal exposure. Most endpoints measured were affected by Zn exposure (320μgZnL -1) during both periods of exposure. APX was the only functional parameter responding after a few hours of Zn exposure, highlighting its use as an early toxicity biomarker. Structural changes began after 3 days of exposure, starting with a decrease in algal biomass and an increase in the OD 430:665 ratio. Structural changes in biofilm communities were observed after 1 week, leading to a shift from diatoms to cyanobacteria and green algae-dominated communities. CAT activity was thereafter enhanced (after three weeks of exposure) and attributed not only to a direct effect of Zn bioaccumulation but also to an indirect effect of the community composition changes driven by chronic metal exposure. It can be concluded that biofilm antioxidant enzyme activities may provide evidence of early stress caused by metal exposure and also provide information about the mechanism of community adaptation. This information can be of great interest to improve current tools used for risk assessment
This study was supported by the Spanish Ministry Project (GCL2006-12785/HID) and grant (FPI20060097171),and the EC Project KEYBIOEFFECTS (MRTN-CT-2006-035695)
Format: application/pdf
ISSN: 0147-6513
Document access: http://hdl.handle.net/10256/12395
Language: eng
Publisher: Elsevier
Collection: MICYT/2006-2009/CGL2006-12785/HID
Reproducció digital del document publicat a: http://dx.doi.org/10.1016/j.ecoenv.2012.02.024
Articles publicats (D-CCAA)
Is part of: © Ecotoxicology and Environmental Safety, 2012, vol. 80, p. 172-178
Rights: Tots els drets reservats
Subject: Ecotoxicologia
Environmental toxicology
Biofilms
Ecologia fluvial
Stream ecology
Marcadors bioquímics
Biochemical markers
Metalls -- Toxicologia -- Aspectes ambientals
Metals -- Toxicology -- Environmental aspects
Title: Antioxidant enzyme activities as biomarkers of Zn pollution in fluvial biofilms
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

Subjects

Authors