The authors of a paper from the Journal of Water, Sanitation & Hygiene for Development have written a blog post summarizing their paper.
Swati D. G. Rayasam, Bakul Rao and Isha Ray
Water Quality Monitoring in a Small Town in India
This research was part of the first author’s (Swati Rayasam) Master’s project.
It seemed a simple-enough research plan: go to Alibag, Maharashtra, conduct a field drinking water test, talk to people about water services, and try to understand the how pervasive antimicrobial resistance was in the drinking water system.
However, in the field we learned that the small town of Alibag conducted their own drinking water tests looking at the Most Probable Number of E.coli per 100mL, not unlike Swati’s own planned tests. Alibag’s tests were conducted at regular intervals and reported to the Department of Water Supply (DWS), reports that were abnormal were sent to the Maharashtra Department of Public Health. However, over an 18-week period, the reports for the most part failed to include a chlorine residual (a quality-control measure) despite having a clear space for it on the form, and not a single report showed any contamination (0 MPN). In contrast, 6 weeks into Swati’s study during the same time period, she had found 30% contamination in her samples, so the official reports were puzzling.
Unable to shake her curiosity, Swati followed a DWS employee at the next round of sample collection. This involved an early morning ride around town, him on a motorcycle and her following closely in a rickshaw. The employee also kindly agreed to submit some samples that Swati collected along with his own batch which were, in effect, duplicates created to compare the testing methods. As per protocol, the samples were supposed to be submitted to the Department of Public Health in 6 hours (max), but later that day as well as the next morning, the DPH hadn’t received them. By the evening of the day after, the samples had arrived at DPH.
Although the laboratory technician was understandably a bit suspicious of Swati, a 25-year-old American-born desi poking around, she still allowed her to observe and make notes, but with strict instructions not to touch anything. Swati watched as she conducted the 5-tube MPN test (perfectly well) and as she conducted the standard chlorine residual test, upon Swati’s request.
The DPH report eventually showed 0 MPN across the board, including of the duplicate samples, but this time it had chlorine residuals. Some of these residuals were 22ppm (virtually undrinkable) at the most distal standpost, while the residuals at the proximate water tower were 7ppm (perfectly plausible). That this occurred naturally is highly improbable. In contrast to the government testing, Swati’s own tests of the duplicate samples showed 100 Ec/100mL and 1.5 Ec/100mL contamination.
So what is going on here? The test protocols were more or less followed, as far as we could see. The town’s water quality testing infrastructure was better than it is in many small towns, in part because Alibag is a popular local tourist destination. This is the central question of our paper (10.2166/washdev.2020.131)
(As an aside, for those who are interested in the sister publication, it can be found here.)