How much spatial and temporal variation in groundwater microbiology can occur following open dumping of municipal solid waste?

The effects of open dumping of municipal solid waste on local groundwater microbiology were assessed in Ranchi, India. Both the spatial and temporal variations of groundwater microbiology were studied. Groundwater was analyzed to determine heterotrophic plate count (HPC), total coliforms (TC) and faecal coliforms (FC). Highest HPC was 4.5 × 104 CFU/mL and the highest total coliform count was 3.7 × 104 CFU/mL. Faecal coliforms were detected in most of the groundwater samples. The highest faecal coliform count of 2.1 × 104 CFU/mL was from a hand pump located adjacent to the dumping site. Spatial variations revealed dispersion of bacterial contamination up to 5 km from the periphery of the municipal solid waste dump. The level of bacterial contamination decreased with an increase in distance from the municipal solid waste dump. The maximum bacterial count was detected in the monsoon whereas the lowest count was found in summer. Molecular characterization of morphologically similar faecal coliform colonies indicated the presence of Klebsiella pneumoniae (Klebsiella ssnkbit, KU647674) in one of the groundwater samples that showed maximum faecal coliform count. Results of this study indicated that groundwater in the area is highly contaminated with a bacterial load which can be a major health risk. HIGHLIGHTS Spatial and temporal variations in groundwater microbiology were assessed due to municipal solid waste dumping.; Faecal coliforms were found in most of the samples.; Bacterial contamination dispersed up to 5 km from the periphery of municipal solid waste dump.; Molecular characterization indicated the presence of Klebsiella pneumoniae in groundwater.;