Waterborne pathogen monitoring in urban India reveals potential infection risks in groundwater supplies

Authors: BIVENS, AARON - Georgia Institute Of Technology; LOWRY, SARAH - Georgia Institute Of Technology; MURPHY, HEATHER - Temple University; Borchardt, Mark; COYTE, RACHEL - Duke University; LABHASETWAR, PAWAN - Csir-National Environmental Engineering Research Institute; BROWN, JOSEPH - Georgia Institute Of Technology

Submitted to: npj Clean Water
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2020
Publication Date: 7/23/2020
Citation: Bivens, A., Lowry, S., Murphy, H.M., Borchardt, M.A., Coyte, R., Labhasetwar, P., Brown, J. 2020. Waterborne pathogen monitoring in urban India reveals potential infection risks in groundwater supplies. npj Clean Water. 3, 35. https://doi.org/10.1038/s41545-020-00081-3.
DOI: https://doi.org/10.1038/s41545-020-00081-3

Interpretive Summary: The Sustainable Development Goals set by the United Nations list as a priority access to clean drinking water free of fecal contamination. The UN recommends fecal contamination be assessed my measuring E. coli bacteria. Achieving this goal in developing countries is challenging. In the city of Jaipur, India, our sampling showed significant contamination of waterborne pathogens in the municipal water supply, especially in the municipal groundwater wells. Under The World Health Organization (WHO) Guidelines for Drinking-Water Quality the number of samples in which we detected E. coli would warrant a “Fair” rating for Jaipur’s drinking water quality. When samples were positive for waterborne pathogens, E. coli also was present only 33% of the time, highlighting the limitation of relying on E. coli as the sole indicator of fecal contamination. We further learned the most advanced techniques for measuring waterborne pathogens have detection limits still too high to determine whether drinking water meets WHO guidelines for acceptable risk. Other approaches in addition to pathogen and indicator measurements will be needed to ensure the clean drinking water goal is achieved.

Technical Abstract: The Sustainable Development Goals require that a water supply be free of E. coli to be classified as “safely managed”. We used dead-end ultrafiltration (DEUF) and droplet digital PCR (ddPCR) along with fecal indicator bacteria measurements to assess the microbial safety of a municipal water supply in Jaipur, India. During our sampling, we detected genes associated with protozoan and bacterial pathogens in groundwater samples from municipal tube wells. Even when using advanced techniques such as DEUF and ddPCR we could not measure pathogens at concentrations corresponding to the WHO acceptable risk threshold of 10-6 DALYs per person per year. Additionally, E. coli detections via routine water quality monitoring techniques only achieved a sensitivity of 33% when compared to molecular detection of waterborne pathogens. Our results indicate, the quality of urban groundwater, especially in the presence of failing or inadequate sanitation, should not be assumed.