黑料网

Abstract

During the present study the uptake and/or removal of lead, cadmium, copper, zinc and iron by six cyanobacterial species isolated from the Egyptian local environments was investigated. These species included Anabaena oryzae (axenic), Anabaena viriabili s (unialgal), Anabaena fertilisma (unialgal), Nostocsp (unialgal), Tolypothrixceytonica (axenic) and Synechocecuslepolensis (axenic) that were exposed individually to three elevated levels I, II and III (5, 10 and 20 ppm) of the tested metals for 5 days. Results revealed that almost all species showed positive correlations with exposure time for removing the tested metals reaching their maximum removal efficiency percentages RE%(s) at the end of the experiment (5 days). Cyanobacterial species accumulated the tested metals in the following order Pb> Fe> Zn> Cd> Cu. Generally, they showed excellent ability for removing the tested metals from the contaminated media with Anabaena viriabilis followed by Tolypothrixceytonica considering the most superior accumulators for almost all the tested metals while Nostoc sp. considered the least promising species. Considerable variations were recorded among the tested cyanobacteria in the removal efficiencies of the tested metals at their three levels. On the other hand, all of the selected species exhibited marvelous resistance against metals toxicity. Results clearly indicated the potential for efficient exploitation of the two most promising species (natural resources) as low-cost, applicable and naturally renewable resources for large-scale metal decontamination processes. Therefore, Anabaena variabilis and Tolypothrixceytonica are highly recommended for application in self-purification and remediation technology of natural water ecosystems and contaminated effluents.

Biography

Ebtesam El-Bestawy is a Professor of Environmental Microbiology & Biotechnology, Institute of Graduate Studies & research, Alexandria University-Egypt. She is currently working for King Abdul-Aziz University, Saudi Arabia. She completed her PhD in Environmental Biology 1993 from Manchester University, Manchester, UK and her postdoctoral research in Biotechnology from the same University as well as Denmark Technical University (DTU), Denmark. She contributed in 13 Training Courses (1993-2010) on environmental wastes: Basic Science and Practical Solutions and participated in 16 national and international conferences and symposia (1988-2010). Her research interests include first study and monitoring of environmental pollutants either organic(pesticides; crude oil etc.) or inorganic (e.g. heavy metals etc.) in aquatic environments and contaminated soils. Second, removal of such pollutants using indigenous and/or exogenous microorganisms in free-living or fixed treatment systems.