Hatha, A A M; Krishna, M P; Rinoy, Varghese(Indian Society for Education and Environment, March , 2012)
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Abstract:
Industrialization of our society has led to an increased production and discharge of both xenobiotic and natural chemical
substances. Many of these chemicals will end up in the soil. Pollution of soils with heavy metals is becoming one of the most
severe ecological and human health hazards. Elevated levels of heavy metals decrease soil microbial activity and bacteria need
to develop different mechanisms to confer resistances to these heavy metals. Bacteria develop heavy-metal resistance mostly
for their survivals, especially a significant portion of the resistant phenomena was found in the environmental strains.
Therefore, in the present work, we check the multiple metal tolerance patterns of bacterial strains isolated from the soils of MG
University campus, Kottayam. A total of 46 bacterial strains were isolated from different locations of the campus and tested for
their resistant to 5 common metals in use (lead, zinc, copper, cadmium and nickel) by agar dilution method. The results of the
present work revealed that there was a spatial variation of bacterial metal resistance in the soils of MG University campus, this
may be due to the difference in metal contamination in different sampling location. All of the isolates showed resistance to one
or more heavy metals selected. Tolerance to lead was relatively high followed by zinc, nickel, copper and cadmium. About
33% of the isolates showed very high tolerance (>4000μg/ml) to lead. Tolerance to cadmium (65%) was rather low (<100
μg/ml). Resistance to zinc was in between 100μg/ml - 1000μg/ml and the majority of them shows resistance in between
200μg/ml - 500μg/ml. Nickel resistance was in between 100μg/ml - 1000μg/ml and a good number of them shows resistance in
between 300μg/ml - 400μg/ml. Resistance to copper was in between <100μg/ml - 500μg/ml and most of them showed
resistance in between 300μg/ml - 400μg/ml. From the results of this study, it was concluded that heavy metal-resistant bacteria
are widely distributed in the soils of MG university campus and the tolerance of heavy metals varied among bacteria and
between locations
Description:
Indian J. Innovations Dev., Vol. 1, No. 3 (Mar 2012)