Seasonal impact on microbiological quality of drinking water in Solan City of Himachal Pradesh, India.

ABSTRACT

Water contamination with faecal matter is usually the main cause of microbial waterborne diseases. Such diseases are an alarming situation for small cities in developing countries like India. In this research, to check the microbiological status of drinking water in Solan, Himachal Pradesh (India), water samples were collected from baories/stepwells (n = 14), handpumps (n = 9), and the municipal water distribution system (MWDS) (n = 2) in alternative months of the year (covering three main seasons). In 6 months, 150 samples were collected, and they were all examined for the presence of total coliforms and other bacterial pathogens. The associations between the isolates' ecological and seasonal prevalence were also examined. The coliforms were detected by the Most Probable Number (MPN) method, whose range was noticed from the 2-540/100-ml MPN index. The colony forming unit (CFU) count for different samples at the base log 10 value ranged from 3.03 to 6.19. Different genera isolated and identified were Escherichia coli, Salmonella enteric subsp. enterica, Pseudomonas spp., Klebsiella spp., and Staphylococcus aureus. Overall, 74% of the isolates identified in water samples were from the Enterobacteriaceae family. E. coli was about 42.67% (n = 102), followed by Salmonella enterica subsp. enterica 20.92% (n = 50), Staphylococcus aureus 13.38% (n = 32), Pseudomonas spp. 12.55% (n = 30), and Klebsiella spp. 10.46% (n = 25) amongst the total of 239 isolates. The seasonal impact and the dependency of the occurrence of bacteria on one another were determined to be insignificant in the Spearman correlation test. These results showed that external factors (anthropogenic activities) are mainly responsible for the presence of these bacteria in water resources. The occurrence of bacterial isolates has been noticed in all water samples, irrespective of collecting site or season.