Tolerance of Bacteria to the Toxic Oxyanions of Arsenic and Lead in Eastern Region of the Nile Valley at Beni-suef, Egypt

This survey focusing on the identification and characterization of the bacteria inhabiting the arsenic (As) and lead (Pb) contaminated regions near the industrial zone of the eastern coast of the Nile valley at Beni-Suef, Egypt. The preliminary results showed that the Arsenic and Lead recorded high levels of contamination (ranging from 4.88-68.8 mg/kg of dry soil for arsenic and 13.6-242.12 mg/kg of dry soil for Lead near the cement and plastic factories located at the eastern part of the Nile valley at Beni-Suef, Egypt. Forty four different bacterial species showing different abil it ies were isolated to util ize the toxic oxyanions of arsenic and lead as energy source to support growth. Thirty eight bacterial species were able to withstand lead toxicity ranging from 3-10 mg/l. interestingly, six isolates out of the 44 bacterial isolates able to respire the toxic oxyanions of arsenic up to 6 mM; one species belongs to gramnegative bacteria and five species belongs to gram positive bacteria. They were able to reduce arsenate to arsenite in the presence of oxygen; word arsenic can serve as an alternative terminal electron acceptor for their respiratory metabolism. Most of the studied isolates grew optimally at temperature range between 28 and 30oC and pH 7.0.