Heavy metals

Pollution has become a global problem and the results are implied in high levels of contaminations reported for soil, water, air, plants and animals. In the present study, Al-Nahrawan is one of the most known industrial regions in Iraq. Samples of soil, water and air were taken for study. These samples were contaminated by different heavy metals like Pb, Cr, Cu, Fe and Zn that were characterized with low pH when compared with normal non industrial regions. The present results indicate that Al-Nahrawan region is affected widely by heavy metals contamination in soil, water and air as a result of industrial activities.

  The present study deals with isolation, identification and characterization of heavy metal resistant bacteria isolated from sewage water collected in and around Trichy district, South India. Initially, among 26 of the total isolates screened from sewage water, one isolate was selected for study based on high level of heavy metal resistances. On the basis of morphological, biochemical, 16S rDNA gene sequencing and phylogeny analysis revealed that, the isolate was authentically identified as Pseudomonas aeruginosa. The sewage isolate exhibited resistance to Silver (Ag), Copper (Cu) and Zinc (Zn). The maximum tolerance concentration (MTC) of the isolate against Ag, Cu and Zn was determined in solid media. The uptake of heavy metals, present in sewage and detoxification of metal ions by bacteria provide an additional mechanism of environmental bioremediation. The identified heavy metal resistant bacteria could be useful for the bioremediation of heavy metal contaminated sewage and waste water. Key words: Heavy metals; copper; silver; zinc; metal tolerance