In 2013-2014, we collaborated with the NCRWSTG and the Guangxi Province China CDC to conduct the first study focused on household water treatment in rural China.
Working together, we developed, tested, and refined new survey questions focused on people’s water-related behaviors and beliefs. These questions were then included in comprehensive household surveys. In the summer of 2013, we trained Guangxi Province China CDC staff and surveyed 450 households in 15 villages across two rural counties – pictures from the county-level training sessions are shown below.
Drinking water samples were collected from each household and tested for indicators of microbial and fecal contamination. Because we understand that boiling would be relatively widespread, we also collected samples from village drinking water sources and analyzed them for indicators of agricultural or industrial contamination. In order to understand potential seasonal variation, in the winter we returned to four of the summer study.
In addition to once again collecting and analyzing water samples, we also placed small remote temperature sensors on kettles and pots in households who boiled in order to better understand boiling behaviors and corroborate the reported boiling data from our surveys.
After initial data analyses, we returned to Guangxi in the Fall of 2014 to meet with Provincial and County China CDC staff to share our preliminary results with them and get their valuable thoughts and feedback on various aspects of the data and our results.
We found that 47.5% of households in the area boiled locally sourced water for drinking, 18.2% did not treat their drinking water, and 34.4% purchased bottled water – the majority of whom also boiled their bottled water before drinking it.
Among other findings, our analyses revealed that households using electric kettles to boil their water had the safest drinking water as compared to households boiling water with pots, or to those households using bottled water. This was, as far as we are aware, the first study to analyze boiling in this way.
Based on this research, we believe that electric kettles offer a number of comparative advantages over boiling with pots, such as:
Reliable pathogen inactivation (because the water is automatically brought to 100°C before the kettle shuts off)
Limited opportunity for secondary-contamination (because the kettles have built-in lids, and cannot be operated when the lid is open – which is essentially a method of safe water storage, making recontamination of the boiled water very unlikely)
High energy efficiency as compared to solid-fuel combustion,
and – importantly – electric kettles do not produce hazardous indoor air pollution.
(see our 2015 PLoS ONE publication for more details).
Additional analyses showed that female-headed households were most likely to boil overall, and among boilers those using electric kettles rather than pots had higher income proxies. Higher-income households with younger, literate, and male heads were also more likely to purchase (frequently contaminated) bottled water, or to use electric kettles if they boiled. We also found substantial contamination in the bottled water samples, but no association between bottled water cost and microbial quality. Looking at the bottled water users overall, the perception that bottled water was convenient appeared to be the primary driver of bottled water use, rather than concerns about safety, or health, for example.
Overall, these findings illustrate that boiling is not an undifferentiated practice, but one with different methods of varying effectiveness, environmental impact, and adoption across socioeconomic strata.
(see our 2017 Environmental Science & Technology publication for more details).