Modeling Exposure to Fecal Contamination in Drinking Water due to Multiple Water Source Use

Abstract

The Joint Monitoring Programme estimated that 71% of people globally had access to "safely managed" drinking water in 2017. However, typical data collection practices focus only on a household's primary water source, yet some households in low-and middle-income countries (LMICs) engage in multiple water source use, including supplementing improved water supplies with unimproved water throughout the year. Monte Carlo simulations and previously published data were used to simulate exposure to fecal contamination (as measured by E. coli) along a range of supplemental unimproved source use rates (e.g., 0−100% improved water use, with the remainder made up with unimproved water). The model results revealed a statistically significant increase in annual exposure to E. coli when individuals supplement their improved water with unimproved water just 2 days annually. Additionally, our analysis identified scenarios−realistic for the data set study setting−where supplementing with unimproved water counterintuitively decreases exposure to E. coli. These results highlight the need for evaluating the temporal dynamics in water quality and availability of drinking water sources in LMICs as well as capturing the use of multiple water sources for monitoring global access to safe drinking water.

Water Quality in Puerto Rico after Hurricane Maria: Challenges Associated with Water Quality Assessments and Implications for Resilience

“…Additionally, the spring sources sampled in this project were used casually before the hurricane but became integral, alternative water sources through SUSU, while many CWS lacked power. Images of alternative water supplies, such as springs, often made international news headlines, , as any available water may be perceived as fit for use during times of stressed water supply. ,,, SUSU is often not captured in public health assessments, but a couple of days of potable use of unimproved sources can significantly increase annual health risks. , Even for non-potable uses, disinfection would also be important due to dermal exposure; Keenum et al (2021) reported that genes associated with Leptospira spp. were detected in all CWS in the Patillas area that used surface water; and there were confirmed deaths after the hurricane due to leptospirosis, which was described as a “hidden outbreak” .…”

“…4,9,10,62 SUSU is often not captured in public health assessments, 7 but a couple of days of potable use of unimproved sources can significantly increase annual health risks. 8,63 Even for non-potable uses, disinfection would also be important due to dermal exposure; Keenum et al (2021) 24 reported that genes associated with Leptospira spp. were detected in all CWS in the Patillas area that used surface water; and there were confirmed deaths after the hurricane due to leptospirosis, 5 which was described as a "hidden outbreak".…”

“…3,4 Potable water services were disrupted, reducing access to potable water by an estimated 70% in the days after the event. 5,6 Return of water services exceeded 70 days in some areas, 4 resulting in supplemental unimproved source use (SUSU) 7,8 with residents relying on streams, wells, and springs. 9,10 In October and November of 2017, the Puerto Rico Department of Health conducted bacterial testing on drinking water systems and found at least one positive sample for the presence of total coliforms or Escherichia coli in water systems that collectively serve millions of residents, including small systems serving 330 households up to large systems serving 1.1 million consumers.…”

“…Estimates of excess deaths range up to 4645 in the months following the hurricane. , This high-end category 4 hurricane significantly impacted infrastructure, compromising 80% of the island’s power transmission systems, and left nearly all residents without power for months . By the end of January 2018, about 40% of the island was still without power. , Potable water services were disrupted, reducing access to potable water by an estimated 70% in the days after the event. , Return of water services exceeded 70 days in some areas, resulting in supplemental unimproved source use (SUSU) , with residents relying on streams, wells, and springs. , In October and November of 2017, the Puerto Rico Department of Health conducted bacterial testing on drinking water systems and found at least one positive sample for the presence of total coliforms or Escherichia coli in water systems that collectively serve millions of residents, including small systems serving 330 households up to large systems serving 1.1 million consumers. , …”

Field trial: disinfection of contaminated anesthetic masks for piglets

“…First, the analysis compared the total bacteria count per mask, the total count of non-hemolytic cocci per mask and the total count of hemolytic cocci per mask between the different sample points. Were the CFU of the variables was 0, these were replaced by 0.5, according to Daly und Harris [ 5 ], to allow for log transformation. Subsequently, a generalized linear mixed model was applied using farms and farm visits as random effects and sampling points nested in farm visits as fixed effect to evaluate whether there was a significant difference between the sample points.…”