Variations in sensitivity to chlorine in Ecuador and US consumers: implications for community water systems

Abstract

Successful implementation of chlorination for disinfecting community water systems in developing countries faces obstacles, with rejection of chlorinous flavor as a significant factor. Determining consumers' abilities to accurately detect chlorine in treated water is important to identifying acceptable chlorination levels that are also effective for water disinfection. Chlorine detection sensitivity was tested in untrained Ecuadorian consumers with limited prior experience with chlorinated water and US consumers with extensive prior experience with chlorinated water.Water samples with free chlorine concentrations up to 3.0 mg/L were presented for flavor testing.Ecuadorian consumers showed higher sensitivity, being able to detect chlorination at 2.0 and 3.0 mg/L, while US consumers did not reliably detect chlorine presence for any concentration levels. Additionally, Ecuadorian consumers' rejection of water samples depended on chlorination, showing a statistically significant increase in rejections of samples with chlorine concentrations above 1.0 mg/L. On the other hand, although US consumers rejected more samples overall, their tendency to reject did not vary as a function of chlorination levels. This study demonstrated that limited experience with chlorination is a critical factor for accurate chlorine flavor detection in drinking water. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited by guest the best evidence-based methods to achieve an accurate description of a substance's (e.g. water) flavor.Affective tests, on the other hand, differ from analytic tests in terms of purpose and implementation. These types of tests are primarily responsible for determining group 429 J. Stout et al. | Chlorine flavor perception

Chlorine Water Taste Threshold and Acceptability among Indigenous and Non-Indigenous Populations in Rural Panama

“…To include this study in the summary in Table 3, it is assumed that at the 4.0 mg/L Cl 2 concentration (maximum allowable EPA health standard), U.S. participants would be able to accurately taste chlorine. Since Stout et al 16 did not perform a threshold analysis, we calculated median thresholds as denoted by the "**" in Table 3. Sample sizes of the studies ranged from 10 participants per study group 10 to 123 participants per study group; 16 however, sample sizes between 40 and 50 participants per study group were the most common.…”

“…These results were in line with expectations that taste thresholds would be most similar to rural and less developed contexts like what was reported in Ecuador and Bangladesh, but differ enough that they also justify the need for site-specific taste threshold research. This study shares many similarities with Stout et al 16 [(1): included rural Indigenous groups, (2): have similar median taste threshold results, (3): have larger sample sizes than commonly reported in the literature, and (4): follow similar procedures and methodology]. However, our study was the only study to report actual best-estimate taste and acceptability thresholds and ranges of these thresholds for both Indigenous and non-Indigenous comparison groups of the same country.…”

“…16 In the U.S. and France studies, the range of taste thresholds varied widely, with French participants having thresholds as low as 0.14 mg/L Cl 2 and US participants not accurately tasting chlorine at 3.0 mg/L Cl 2 . 13,16 Chlorine acceptability has been studied at the household level as well, but without a focus on Indigenous groups. 3,18 Furthermore, recent research indicates that certain regions use chlorine more often�Africa and Latin America� suggesting passive chlorination may have higher acceptance in these regions than in others.…”

“…The concentration of chlorine residual needed to inactivate common pathogens in potable water (and limitations in inactivating some pathogens such as protozoa and helminths) is well-documented. ,, However, an individual or household’s willingness and ability to adopt and sustain chemical disinfection by chlorine are more complicated. Previous research on the concentration of chlorine where an individual can detect its presence (taste threshold) and the concentration of chlorine an individual will no longer accept the water for drinking (acceptability threshold) is critical for community acceptance; yet, most of this research is centered in middle- to high-income country contexts. − More recent work has considered biogenic taste and odor associated with algal blooms . Other studies have assessed the type (liquid vs tablet) and method (piped vs point of use) of chlorination and the effects on taste thresholds for a singular population. , …”

Storage tanks for household water usage in Brazil: Microbiological and chemical quality, and maintenance of sanitary conditions

“…This study illustrated in a simplified way the perception of some residents regarding the need for cleaning and maintaining domestic water tanks, indicating the need to increase popular awareness about the quality of water consumed. Some authors found that people do not trust the quality of water coming to their homes, leading them to consume bottled water for direct ingestion, using tap water for hygiene and household cleaning 13 .…”