کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4420678 1618983 2012 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Antioxidant enzyme activities as biomarkers of Zn pollution in fluvial biofilms
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم محیط زیست شیمی زیست محیطی
پیش نمایش صفحه اول مقاله
Antioxidant enzyme activities as biomarkers of Zn pollution in fluvial biofilms
چکیده انگلیسی

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 6 h, 1, 3, 7, 21 and 35 days of metal exposure. Most endpoints measured were affected by Zn exposure (320 μg Zn L−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.


► Different response of CAT and APX activities in front Zn exposed biofilm.
► Microcosm allow to reproduce environmental Zn exposure conditions in biofilms.
► AEA are more sensitive biomarkers of acute metal exposure than other parameters.
► AEA can be used as early warning system of toxicity in metal polluted biofilms.
► AEA as biomarkers of community adaptation in metal exposed fluvial biofilms.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ecotoxicology and Environmental Safety - Volume 80, 1 June 2012, Pages 172–178
نویسندگان
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