The impact of heavy metals viz., Pb, Hg, Fe and Cu on microbial populations of tea garden soil was studied under laboratory conditions. The soils were treated with 100, 150 and 200 μg g−1 of each metal individually. A significant inhibition in microbial population was observed due to the application of heavy metals, with actinomycetes being the severely affected group. Aerobic heterotrophic bacteria were more sensitive to Hg followed by Pb and Cu. Actinomycetes population was drastically reduced even at 100 μg g−1 concentration. Fungi were more vulnerable to Pb at elevated concentrations. Among the heavy metals tested, Hg proved highly detrimental to the indigenous microbial population followed by Pb and Cu.
Actinomycetes, bacteria, fungi, heavy metals, heterotrophic microbes, tea rhizosphere soil
