The Effect of Heavy Metals on the Growth of Waterborne Escherichia coli of Municipal Landfill Origin

The aim of this study was to assess the sensitivity of Escherichia coli isolates originating from a municipal waste landfill to the selected heavy metals. The analyses were conducted using environmental strains, isolated from surface water – a stream flowing along the landfill and from leachate and the observations were compared to the reaction of a reference strain EC ATCC 25922. The growth rate of bacterial cultures was evaluated in the liquid medium supplemented with 0.02; 0.1 and 0.5 mg dm of heavy metal salts: chromium, zinc, cadmium, copper, lead and mercury. The bacterial growth was examined turbidimetrically every 24 hours for 5 days. The performed study showed differences between the examined isolates in their response to the addition of the heavy metals in the liquid medium. Additionally, varied intensity of the heavy metals’ effect on bacterial growth was observed, with the weakest growth inhibition being recorded in the case of lead, while chromium and mercury causing the greatest growth inhibition of bacterial strains.