Quantitative Microbial Risk Assessment to Estimate the Health Risk in Urban Drinking Water Systems of Mysore, Karnataka, India

摘要

Quantitative microbial risk assessment (QMRA) is a valuable tool for estimating the burden of disease due to exposure of a particular microbial pathogen. In this study, we used the quantitative risk assessment method to calculate the burden of disease with special reference to gastroenteritis from three reference pathogens-Escherichia coli, Campylobacter, and Rotavirus in the drinking water treatment systems of Mysore Urban city, Karnataka, India. A total of 140 samples were analyzed over a period of 24 months in different seasons using standard methods. The risk burden was estimated by guidelines for drinking water quality (WHO in Campylobacter, factsheet no. 255, 2011a; Guidelines for drinking water quality, 2011b) method. The results show that the Mysore Urban population connected to the current drinking water treatment plant seems to be vulnerable to waterborne gastroenteritis diseases since the results indicate less effectiveness on pathogen removal in treatment system. The result reveals that the pathogenic E. coli disease burden from Melapura plant shows a slower level (6.74E-07) than the WHO reference (10E-06) level. The risk estimates for Campylobacter show that they slightly exceed by (2.54E-06) over the WHO guidelines. The final disease burdens (db) of Rotavirus were lower for the both the treatment plants (Melapura-4.75E-07 and Hongally-2.54E-06) compared with the WHO reference. Overall, the estimates for the annual risks of infection of E. coli and Campylobacter were in excess of the WHO guideline values. The present QMRA study is believed to be the first attempt and to be useful for the local authorities and stakeholders to evaluate the likely risk of infection and to ensure the better management of water supplies in India.