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Bottled water quality and associated health outcomes: a systematic review and meta-analysis of 20 years of published data from China

Alasdair Cohen 7,1,2 , Jingyi Cui 3 , Qingyang Song 3 , Qiwen Xia 3,4 , Jiexuan Huang 3 , Xinjia Yan 3,4 , Yalu Guo 5 , Yixin Sun 5 , John M Colford Jr 6 and Isha Ray 2,4

Published 20 January 2022 • © 2022 The Author(s). Published by IOP Publishing Ltd Environmental Research Letters , Volume 17 , Number 1 Citation Alasdair Cohen et al 2022 Environ. Res. Lett. 17 013003 DOI 10.1088/1748-9326/ac2f65

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1 Department of Population Health Sciences, Virginia Polytechnic Institute and State University, 205 Duck Pond Dr Blacksburg, VA, 24061, United States of America

2 Berkeley Water Center, University of California, Berkeley, CA, United States of America

3 College of Letters and Science, University of California, Berkeley, CA, United States of America

4 Rausser College of Natural Resources, University of California, Berkeley, CA, United States of America

5 College of Engineering, University of California, Berkeley, CA, United States of America

6 School of Public Health, University of California, Berkeley, CA, United States of America

Author notes

7 Author to whom any correspondence should be addressed.

• Received 11 August 2021
• Accepted 13 October 2021
• Published 20 January 2022

Peer review information

Method : Double-anonymous Revisions: 1 Screened for originality? Yes

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Bottled water is a rapidly growing yet relatively understudied source of drinking water globally. In addition to concerns about the safety of bottled water, the adverse environmental health and social impacts associated with bottled water production, distribution, consumption, and reliance are considerable. Our objective was to comprehensively review, analyze, and synthesize ∼20 years of publicly available data on bottled water quality and associated health outcomes in China. We conducted a systematic review and meta-analysis of publicly available studies of bottled water quality and associated health outcomes in China published between 1995 and early 2016 (in Chinese and English). We pre-specified and registered our study protocol, independently replicated key analyses, and followed standardized reporting guidelines. Our search identified 7059 potentially eligible records. Following screening, after full-text review of 476 publications, 216 (reporting results from 625 studies) met our eligibility criteria. Among many findings, 93.7% (SD = 10.1) of 24 585 samples tested for total coliforms ( n = 241 studies), and 92.6% (SD = 12.7) of 7261 samples tested for nitrites ( n = 85 studies), were in compliance with China's relevant bottled water standards. Of the studies reporting concentration data for lead ( n = 8), arsenic ( n = 5), cadmium ( n = 3), and mercury ( n = 3), median concentrations were within China's standards for all but one study of cadmium. Only nine publications reported health outcome data, eight of which were outbreak investigations. Overall, we observed evidence of stable or increasing trends in the proportions of samples in compliance over the ∼20 year period; after controlling for other variables via meta-regression, the association was significant for microbiological but not chemical outcomes ( p = 0.017 and p = 0.115, respectively). Bottled water is typically marketed as being safe, yet in most countries it is less well-regulated than utility-supplied drinking water. Given the trend of increasing bottled water use in China and globally—and the associated environmental health impacts—we hope this work will help to inform policies and regulations for improving bottled water safety, while further highlighting the need for substantially expanding the provision of safe and affordable utility-supplied drinking water globally.

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1. Background and justification

From the 1990s on, global consumption of bottled water has grown rapidly as it has expanded from markets primarily centered in high-income countries (HICs) to those in low- and middle-income countries (LMICs). The majority of the world's bottled water is now consumed in LMICs [ 1 ]. Global growth in bottled water consumption is attributed to consumer demand—driven by perceptions that it is safe and convenient—and is fueled by widespread marketing [ 2 ]. Studies on consumer preferences in HICs find that perceived safety and convenience are the primary reasons for bottled water use [ 3 , 4 ]. While utility-provided safe water access has expanded over the last few decades in most large LMICs, consumption of bottled water has increased far more rapidly [ 5 ].

Compared with water utilities that supply piped drinking water (municipal water), regulations for bottled water production in LMICs and HICs are typically less rigorous, and water quality testing and monitoring are required far less frequently. One of the few relatively extensive and publicly available studies on bottled water in the USA concluded that bottled water was not necessarily safer than tap water overall, and ∼20% of the brands tested were contaminated at levels above California's standards [ 6 ].

Beyond concerns about the safety of bottled water, the negative social and environmental health impacts associated with bottled water production, distribution, consumption, and reliance are considerable. Bottled water costs hundreds to thousands of times more per liter than treated piped water [ 2 , 6 ], and the negative environmental impacts associated with single-use plastic bottle production and disposal have become a global concern [ 7 ]. Life cycle assessments of bottled water production, transportation, and associated waste help quantify the scope of adverse environmental impacts and demonstrate that contributions to greenhouse gas emissions are orders of magnitude higher than those associated with utility water supply [ 8 , 9 ]. In recent years, multiple studies have found microplastic contamination to be near-ubiquitous in surface waters, and frequently detected in bottled water samples as well [ 10 , 11 ].

At this writing, we are aware of only two published bottled water focused systematic reviews. Williams et al [ 12 ] conducted a relatively comprehensive review focused on fecal contamination in packaged and bottled water in LMICs; however, as the authors noted in their review, they did not include results from China due to the language barrier. The other systematic review focused only on fluoride concentrations in bottled water [ 13 ], but likewise did not review Chinese-language results. In addition, in a recently published non-systematic review [ 14 ] focused on emerging contaminants (including microplastics), as well as contamination attributed to the types of plastic used for water bottles, the authors did not appear to include results from Chinese-language publications. This is noteworthy when one considers that in 2013, China surpassed the USA to become the world's largest market for bottled water by volume [ 15 ]. Furthermore, limited available data indicate that even in rural China more and more households are turning to bottled water (19 l bottles) as their primary source of drinking water [ 16 , 17 ].

Thus, there appears to be a substantial 'China gap' in the bottled water research literature. China's population is large, its consumption of bottled water is increasing, and it has a relative wealth of publicly available data from published studies on bottled water quality—in contrast to the relatively limited bottled water focused research literature from the USA or Europe. To address this research gap, we conducted a systematic review and meta-analyses focused on bottled water contamination and associated health outcomes in China. The objective of this work was to synthesize publicly available data on bottled water contamination in China published over a period of approximately two decades, analyze data and trends, and attempt to shed light on the underlying causes of reported bottled water contamination.

We conducted a systematic review of published and publicly accessible studies on bottled water contamination and associated health outcomes in China. We registered our study protocol with the International Prospective Register of Systematic Reviews (PROSPERO, 2016:CRD42016048863, www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42016048863 ) and on Open Science Framework (OSF; including our search terms, sets, code, and relevant Chinese/English translations: https://osf.io/yqbdy ). All statistical analyses were conducted using Stata (v.15), and our primary analyses were independently replicated using R (v.4.0.3). This manuscript was prepared in accordance with the PRISMA reporting guidelines [ 18 ], and a completed checklist is provided in the last section of the supplementary material (SM).

2.1. Eligibility criteria

We wished to collect and analyze data from any study or investigation of bottled water quality in China. Studies were considered eligible if they measured, quantified, evaluated, assessed, or otherwise tested bottled water samples in China for microbiological and/or chemical contaminants (including heavy metals and radionuclides, but not microplastics), reported original analyses and results, were conducted during or after 1990, and were published between 1995 and early 2016. We did not limit our eligibility based on who evaluated the water quality (universities, government agencies, private companies, other) or based on the type of study design, use of comparison groups, controls, or specific water sampling methods. For the purposes of this review, bottled water was defined as any type of packaged drinking water.

For our key outcome measures, we considered any microbiological contaminants with known links to health to be eligible (whether reported as presence/absence, percentage of samples meeting national/local standards, or mean or median concentrations), provided that such outcomes were directly assessed/measured. Studies based on qualitative descriptions of bottled water quality were not considered eligible. We used these same criteria for chemical contaminants with known or suspected links to health (organic, inorganic, radionucleic, disinfection byproducts). Similarly, we considered any health outcomes with direct or hypothesized links to the consumption of bottled water to be eligible, provided the study also assessed at least one indicator of bottled water contamination. Additional details on our inclusion and exclusion criteria are provided in our PROSPERO protocol (2016:CRD42016048863).

2.2. Search strategy

To identify potentially eligible studies, we searched the primary Chinese-language databases, CNKI ( www.cnki.net/ ) and Wanfang ( http://librarian.wanfangdata.com.cn ), as well as the online databases PubMed/MEDLINE, EMBASE, and Web of Science. We limited our searches to all records (English or Chinese) published from 1995 to April 2016, when the searches were conducted.

For CNKI, we searched titles and abstracts in six separate databases; for Wanfang we searched titles, keywords and abstracts in nine separate databases. For the Chinese-language databases we used three sets of search terms to identify all records related to: bottled water, microbiological contaminants , and/or chemical contaminants . For water contaminants (microbiological, chemical, etc) we included all parameters listed across China's official Drinking Water Standards at the time of the search, as well as any additional parameters listed in drinking water standards of the World Health Organization and US Environmental Protection Agency.

For the databases PubMed/MEDLINE, EMBASE, and Web of Science, early piloting of our search terms and sets showed that there were very few records related to bottled water in China. Therefore, to ensure that we identified all potentially eligible records in these three databases, we used search sets and search terms for bottled water and China (all variants of the country name), and did not use search sets and terms to specify individual microbiological and chemical parameters. To ensure that we did not inadvertently overlook non-Chinese language records using the term 'packaged water' (rather than 'bottled water'), a search for 'packaged water' and the variants of 'China' (e.g. 'PR China') was also conducted via a hand-search using Google Scholar.

All search sets and terms, as well as English translations of Chinese search terms, the search code used for database searches, as well as additional notes, are available online on OSF (at https://osf.io/yqbdy ).

2.3. Record screening, data extraction, and derivation protocols

Three reviewers (XY, QX, QS) screened all available titles and abstracts to identify potentially eligible records for full-text review. For the initial record screening step, to avoid inadvertent bias from viewing author name/s, publication type, journal names, etc, only the record titles and abstracts were reviewed. Any records that, based on the content in the title and/or abstract, could have possibly discussed bottled water related analyses in China were retained. To assess inter-rater reliability and evaluate the potential need for full duplicate title/abstract screening, 100 records were selected at random and independently screened by all three reviewers (XY, QX, QS).

Five researchers (QS, QX, JC, PD, JT) reviewed all the potentially eligible full-text records to determine eligibility for data extraction. For each eligible study with extractable data, data was entered into a pre-specified data extraction template (using Google Sheets). To assess the accuracy of the data extraction, data from a random selection of ∼10% of eligible full text records were extracted independently by pairs of reviewers. Following initial data review, to facilitate data cleaning three researchers (QS, QX, JC) reviewed the extracted data for all full-text records assessed to be eligible for inclusion. Given the number of parameters for which we sought to extract data, following these steps we conducted extensive quality control and data cleaning over a period of multiple years.

2.4. Data analyses

Assuming sufficient data was available, our pre-specified objective was to conduct meta-analyses for all primary contaminant classes as well as for specific contaminants, indicators of contamination, and testing methods. For our analyses of health outcomes, we anticipated that inter-study variability (resulting from differences in study designs, bottled water types, sample collection methods, analytic protocols, etc), as well as random error, would be best addressed by using meta-analysis with a random-effects based weighting. If the data structure permitted, we also pre-specified to conduct a meta-regression analysis (with random effects).

We pre-specified subgroup analyses in our protocol (and also as a means of evaluating expected heterogeneity, using standard methods such as the I-squared statistic). To assess studies by climatic region, we binned studies based on province into four categories [ 19 ]: cold and mild temperate, warm temperate, mild subtropical, and subtropical/tropical (see table S1 available online at stacks.iop.org/ERL/17/013003/mmedia ).

We conducted meta-regression analyses to assess heterogeneity and potential confounders, using a generalized linear model with a logit link, binomial distribution, and cluster-robust standard errors (treating included eligible papers as clusters to adjust for outcomes from multiple sub-studies). For our meta-regression analyses, our outcome variable was the reported passing rate (expressed as a proportion) for all microbiological and chemical parameters for which we extracted data, and we analyzed the following covariates: the year of study publication, the study setting (rural, urban, other), the study setting climate, an indicator of provincial level economic consumption (low, medium, and high levels), the type/source of the bottled water (mineral, spring, purified, other), and the number of bottled water samples analyzed. Because many publications reported multiple results for the same parameters from different sub-studies, standard errors were adjusted to control for the clustered nature of the data.

2.5. Assessment of bias

We anticipated significant heterogeneity in study methods and reporting among those records eligible for data extraction. To assess risk of bias (ROB), we adapted approaches from previously published systematic reviews [ 20 – 22 ] and created a composite index based on six variables (assessing sampling methods and how study methods and protocols were reported), each of which was scored on a three-point scale (see table S2 for details). To assess potential publication bias, we used standard methods (Egger's test, funnel plots).

3.1. Search and screening results

Our search resulted in the identification of 7059 potentially eligible records (after duplicate removal) (figure 1 ). Through title and abstract screening, we identified 476 potentially eligible records. For the randomly selected sub-sample of 100 records the kappa statistic for three reviewers (XY, QX, QS) with two possible outcomes (yes, no) was 0.83 ( z = 14.3, p < 0.001), indicating a very high degree of inter-rater agreement [ 23 ]; therefore, we did not conduct additional duplicate review for the title/abstract screening stage. Of the 476 records identified for full-text review, we were unable to find the full text for 39, and a further 221 were excluded for various reasons, as outlined in figure 1 (additional details in table S3).

Figure 1.  Study screening and selection flow chart.

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3.2. Characteristics of eligible studies with extractable data

All 216 of the eligible records with extractable data were journal publications; 110 reported results for microbiological parameters only [ 24 – 133 ], 67 reported results for microbiological and chemical parameters [ 134 – 200 ], 30 reported results for chemical parameters only [ 201 – 230 ], and nine reported results for health outcomes and microbiological parameters [ 231 – 239 ].

As shown in table 1 , of the publicly available records which were eligible for inclusion in our review, 84% ( n = 182) were authored by employees from Chinese government agencies. Among these 182 records, 43% ( n = 78) were published by authors from various Center for Disease Control and Prevention (CDC) agencies, 29% ( n = 53) by authors working at government Sanitation and Anti-Epidemic Stations, and 15% ( n = 27) by authors from Institutes for Health Inspection. Sanitation and Anti-Epidemic Stations were the predecessors for today's China CDC agencies, and Institutes for Health Inspection are affiliated with the China CDC, meaning the vast majority of studies that were eligible for inclusion in our review were conducted and published by authors from China CDC and affiliated agencies.

Table 1.  Overview of eligible records with extractable data.

Notes: Gov. = government; Uni. = university; BW = bottled water; nfs = not further specified.

Across the 216 eligible papers, results from 625 studies were reported (i.e. multiple results reported for parameters based on the analysis of samples collected from different sources and locations). Most studies reported results for water quality parameters in terms of the 'passing rate'; that is, the proportion of samples with test results that were in compliance with the relevant Chinese bottled water standards at the time of the study (the passing rate, '合格率', is a commonly-used metric in China).

Of the papers that reported one or more microbiological outcomes ( n = 186), only 10% ( n = 18) provided specific concentrations (e.g. coliform forming units/100 ml). Of the papers that reported one or more chemical outcomes ( n = 97), 28% ( n = 27) reported results in terms of specific concentrations (e.g. mg l −1 ). In addition to extracting reported data, in cases where sufficient data for passing rates and/or concentrations were reported, we also calculated concentrations and passing rates ourselves (equations for such calculations, along with notes describing where data were found, are embedded in the relevant cells in our SM excel data file available online at stacks.iop.org/ERL/17/013003/mmedia ). Summary tables for China's primary bottled water, and drinking water, standards are provided in tables S4 and S5.

We extracted data on the location of the study by province (figure 2 ) and setting where study samples were collected: rural, urban or peri-urban, or a combination thereof (table 1 ). The majority of studies—overall and by paper type (microbiological, chemical, microbiological and chemical, health outcomes)—were conducted in the relatively higher-income provinces along China's coast (figure 3 ). We also sought to extract data on the brands of water tested, but this information was provided for only a few studies. Similarly, we attempted to extract data on the method(s) of bottled water treatment used, but only 16 eligible papers provided such information. A histogram of eligible papers by year of publication and paper type is provided in figure S1.

Figure 2.  Map of China with number of eligible publications with extractable data by province: all study types. Note: three publications (Wu Q 2009, Xu B 2001, and Zhang Z 2009) reported data from multiple provinces.

Figure 3.  Eligible publications with extractable data by province: microbiological outcomes (a), microbiological and chemical outcomes (b), chemical (c), health outcomes (d). Note: three publications (Wu Q 2009, Xu B 2001, and Zhang Z 2009) reported data from multiple provinces.

3.3. Microbiological outcomes

Studies that reported results for only microbiological parameters are summarized in table 2 , and those that reported results for microbiological and chemical parameters are summarized in table 4 . As shown in figure 4 , for those studies reporting data for specific pathogens such as Salmonella, Shigella, and Staphylococcus, in almost all cases the samples were reported to be in compliance with China's relevant bottled water standards at the time the studies were conducted (boxplots are shown in figure S2). However, for several indicators of microbiological contamination, such as total bacteria and total coliforms, many bottles water samples were assessed to exceed the relevant standards (i.e. were not in compliance).

Figure 4.  Passing rate means and 95% confidence intervals (CI) for selected microbiological parameters.

Table 2.  Overview of eligible records with microbiological outcomes ( n = 110).

Notes: nfs = not further specified; MD = missing data.

Table 4.  Overview of eligible records with microbiological and chemical outcomes ( n = 67).

Across microbiological parameters, most studies reported data for total bacteria and total coliforms. As shown in table 3 , the mean passing rate from 297 studies of total bacteria was 71.1% (SD = 18.5), and 93.7% (SD = 10.1) for the 241 studies of total coliforms, and 88.9% (SD = 5.8) for the 17 studies of P. aeruginosa (see table S6 for unweighted data).

Table 3.  Summary statistics for reported passing rates for selected microbiological parameters.

Notes: nfs = not further specified. Statistics weighted by study sample sizes. Excludes results from eight publications reporting results from outbreak investigations. a Study authors reported aggregated results using this classification, with insufficient available data to extract 'passing rate' results for specific organisms.

As shown in figure 5 , looking at passing rate results by year of study publication, from the late 1990s to late 2000s the mean proportion of samples in compliance increased (improved) slightly for total bacteria. We did not observe evidence of strong temporal trends for total coliforms (publication-specific boxplots for both parameters in figures S3 and S4).

Figure 5.  Samples in compliance for total bacteria and total coliforms by publication years.

3.4. Chemical outcomes

Studies that reported results for chemical parameters are summarized in tables 4 and 5 . Among chemical parameters analyzed, results for lead, arsenic, and nitrite were most commonly reported. Mean passing rates for most parameters were >95% (figure 6 and table 6 ) though this was not the case for nitrites (mean = 92.6%) or for disinfection byproducts (mean = 71.2%) (boxplots in figure S5 and unweighted data in table S7).

Figure 6.  Passing rate means and 95% confidence intervals (CI) for selected chemical parameters.

Table 5.  Overview of eligible records with chemical and related outcomes ( n = 30).

Note: MD = missing data.

Table 6.  Summary statistics for reported passing rates for selected chemical parameters.

Notes: nfs = not further specified. Statistics weighted by study sample sizes. a Study authors reported aggregated results using this classification, with insufficient available data to extract 'passing rate' results for specific organisms or indicators.

Looking at the results from studies that measured nitrite and nitrate by year of study publication (figure 7 ), there is evidence of a positive trend over most of the time span covered in our review (i.e. studies reported higher average passing rates); the trend is more pronounced for nitrites than for nitrates (publication-specific boxplots in figures S6 and S7).

Figure 7.  Samples in compliance for nitrate and nitrite by publication year.

As discussed previously, relatively few studies reported results in terms of specific concentrations. Across the papers that did report specific concentrations for lead ( n = 8), cadmium ( n = 3), arsenic ( n = 5), and mercury ( n = 3), aside from one study reporting results for cadmium (Zhou 2016) median concentrations for these heavy metals were all in compliance with China's national bottled water standards (figure 8 ) (additional details in table S4).

Figure 8.  Boxplots of reported concentrations by study for lead (a), cadmium (b), arsenic (c), and mercury (d), with references to China's national maximum contaminant standards for bottled water (GB19298-2003) (red dashed lines) (additional details in table S4).

3.5. Health outcomes

Studies that reported results for health outcomes and microbiological parameters are summarized in table 7 . Eight of the nine studies which reported data for health outcomes were outbreak investigations, and of those, only four (case-control study designs) reported sufficient data for comparative analysis. As shown in figure 9 , across these four case-control outbreak investigations, consumption of bottled water was significantly associated with an increase in the pooled odds of reported gastrointestinal illness (logged OR = 1.90, p < 0.001). However, because these investigations were conducted in response to disease outbreaks, and focused on student populations, the results are not generalizable to more typical situations and settings.

Figure 9.  Forest plot—case-control studies of bottled water consumption and gastroenteritis.

Table 7.  Overview of eligible records with health and microbiological outcomes ( n = 9).

Note: nfs = not further specified.

Funnel plot asymmetry indicated some evidence of potential publication bias (see figure S8). It is reasonable to assume that similar case-control studies with null findings may have been conducted over this time period, but were perhaps not submitted for publication. More broadly, the nature of these studies limits our ability to generalize beyond outbreak settings.

3.6. Meta-regression

As shown in table 8 , results from meta-regression analyses indicated that, after controlling for other variables in the models, reported passing rates for microbiological and chemical outcomes were positively associated with the year of study publication, though the association was only statistically significant for microbiological outcomes, and not for chemical outcomes ( p = 0.017 and p = 0.115, respectively) (model-predicted passing rates for both outcomes in figures S9 and S10). Reported passing rates were significantly lower (i.e. worse) for studies conducted in rural regions compared with urban and other settings, for both microbiological and chemical outcomes ( p = 0.041 and p = 0.002, respectively); however, relatively few studies ( n = 13 and n = 2, respectively) were conducted in primarily rural settings (table S8).

Table 8.  Meta-regression results for proportion of microbiological and chemical samples in compliance.

Note: Excludes results from eight publications reporting results from outbreak investigations; BW = bottled water. a Cluster-robust standard errors (to adjust for publications reporting results from multiple studies).

4. Discussion

4.1. results in context: climate and economic indicators.

We observed some evidence of differences in mean passing rates for microbiological outcomes, but not for chemical outcomes, by climatic region (table 9 and figure S11). This observation of higher overall passing rates in warmer and wetter regions (i.e. more samples found to be in compliance compared with cold/mild and warm regions) is potentially at odds with previous drinking-water focused research which found higher overall prevalence of fecal indicator organisms in wetter and warmer conditions [ 240 ]; though this would likely depend, among other factors, on bottled water storage durations prior to testing (and we lacked the data needed to evaluate this potential association).

Table 9.  Passing rates for microbiological and chemical outcomes by study climatic region.

Notes: Means and standard deviations adjusted using sample size based weights. Excludes results from eight publications reporting results from outbreak investigations.

To evaluate the potential impacts of broader economic indicators and socioeconomic status by study setting, we used 2012 Household Consumption Expenditure data from China's National Bureau of Statistics [ 241 ] as a comparative indicator of economic status by province. After sorting provinces into thirds based on this expenditure data, we observe that for microbiological outcomes the mean passing rate from studies conducted in provinces with lower annual consumption expenditures (RMB 8–15 × 10 7 ) was significantly lower compared with the mean from provinces with higher (RMB > 20 × 10 7 ) consumption expenditures (80.1% and 86.8%, respectively; ANOVA, using analytic weights based on sample size, Scheffe's test, p < 0.001). No significant differences in passing rates by levels of consumption expenditures were observed for chemical outcome data (table S9). However, after controlling for other covariates in our meta-regression models (table 8 ), we did not observe any significant associations between these economic indicators and overall passing rates.

4.2. Results in context: bottled water characteristics

Compared with mineral, spring, and other types of bottled water, results from the meta-regression show that passing rates were higher for samples from 'purified' bottled water, and the associations were statistically significant for both microbiological and chemical outcomes ( p = 0.021 and p = 0.014, respectively). However, bivariate analysis of passing rates and bottled water type did not indicate substantive differences in this regard (see table S10).

With regard to the size of the water bottles sampled, we did not observe any significant differences in mean passing rates for chemical outcomes and bottle size (table 10 ). However, for studies reporting microbiological outcomes based on samples from smaller water bottles (<2 l), the mean passing rate (72.1%) was more than 10% points lower than the mean passing rate (83.4%) from studies of larger water bottles (>10 l) (Analysis of variance [ANOVA], using analytic weights based on sample size, Scheffe's test, p < 0.001 for comparison between small and large categories).

Table 10.  Passing rates for microbiological and chemical outcomes by bottled water size.

Notes: Means and standard deviations adjusted using sample size based weights. Excludes results from eight publications reporting results from outbreak investigations. a Study authors reported combined results from analysis of small and large bottles.

Looking at only those studies that reported results for total coliforms (table 10 ), we see that the mean passing rate is also significantly lower for small bottles compared with larger ones (ANOVA, using analytic weights based on sample size, Scheffe's test, p < 0.001 for comparison between small and large categories). These findings with regard to small versus large bottles and microbiological passing rates are somewhat at odds with previous research (outside of China) which found more evidence of microbiological contamination in larger water bottles [ 12 ]. Whereas 131 papers reported the size of the water bottles sampled in qualitative terms (e.g. 'small', 'large'), only 21 papers reported the specific size of the bottles in number of liters. For those papers ( n = 21), the data are suggestive of higher levels of microbiological contamination (i.e. lower passing rates) in larger bottles, but the differences between smaller bottles (<1 l) and large (∼19 l) was not significant (see figure S12). With regard to contamination and risks of exposure associated with the use of small- or large-sized bottles, most Chinese households who use large water bottles heat or boil the water before consuming it, a practice that would be expected to reduce pathogen exposure [ 22 , 242 ]; this is not typically the case with small, single-use, water bottles. That said, because larger bottles are not typically consumed immediately after being opened, consumption over a period of days or weeks could provide more time for organism growth if the bottled water was already contaminated when purchased, or became so after the bottle was opened. Overall then, we cannot draw clear conclusions from these data with respect to relationships between bottled water size and reported passing rates.

4.3. Methodological rigor and risk of bias analysis

Studies were assigned an ROB score based on six items (table S2) and were then divided into thirds and assigned to groups for low, medium, and high ROB (table S11 and figure S13). Looking at passing rate trends by publication year, for studies assessed to have a higher ROB (i.e. a higher likelihood of methodological shortcomings or other limitations) the average reported passing rates were lower overall (i.e. worse) compared with studies assessed to have a medium or low ROB for microbiological and chemical outcomes (figures S14 and S15).

One of the components used to estimate ROB was study sample size. As shown in table 8 (and table S12), we did not observe significant differences in mean passing rates for microbiological outcomes based on the number of bottled water samples used in the underlying studies. However, for studies reporting chemicals outcomes based on relatively large sample sizes (i.e. ⩾61 bottled water samples) the mean passing rate (91%) was significantly lower than for the smaller sample size categories (table S12; ANOVA with Scheffe's test, p < 0.05 for all three comparisons).

4.4. Author-provided hypotheses for observed contamination

The primary objectives of this review were to better understand the nature of bottled water quality in China and to elucidate some of the reasons for observed contamination, with the larger goal of potentially identifying management or policy approaches that could prevent or mitigate contamination. Based on the nature of the available reported data, we cannot responsibly make inferences with regard to reasons for the microbiological and chemical contamination observed. However, in most cases the authors of the individual papers did provide hypothesized explanations for their findings. To examine some common themes across studies, we extracted and synthesized author-provided explanations for observed contaminations (these author-provided explanations should be treated as informed opinions rather than as evidence).

Explanations for observed microbiological contaminants are summarized in figure 10 by climatic region. The hypothesized reasons varied, but in all climatic zones most authors postulated that contamination was due to insufficiently sanitary bottled water production, insufficient source water treatment, insufficient sanitation of reused bottles (typically the large ∼19 l bottles) and insufficient regulations or oversight. Slightly more authors of studies published in subtropical regions hypothesized that the source water was microbiologically contaminated, but this observation may be driven by other factors (e.g. more of China's less economically developed provinces are situated in subtropical regions).

Figure 10.  Hypothesized reasons study authors provided for observed microbiological contamination.

Looking at author-provided explanations for observed chemical contamination over levels of annual consumption expenditures (figure 11 ), we see that most authors mention the same reasons as those offered for microbiological outcomes. However, more authors hypothesized that contaminated source water was an important factor, particularly in provinces with higher indicators of economic development. The confluence of industrialization, economic production, and higher province-level household consumption expenditures might partially explain this association, but as with the would-be explanations associated with microbiological outcomes, other factors are likely relevant as well.

Figure 11.  Hypothesized reasons study authors provided for observed chemical contamination.

4.5. Study limitations

Findings from our review summarize only publicly available data from eligible published studies and are unlikely to be representative of the situation across China with respect to bottled water quality for the approximately 20 year period from 1995 to the beginning of 2016. In addition, because the majority of the reviewed papers came from relatively more economically developed provinces (figure 2 ), our findings are likely not representative of less-developed provinces in China. Only a few studies reported which brands of bottled water were tested, or provided information specific to the source-water location; therefore, we were unable to analyze results based on where bottled water was sourced geographically, or where production facilities were located. We tentatively assumed that in most cases the bottled water sampled was from companies that sourced and produced the bottled water within the province where the study was conducted, or within the region surrounding the province. However, some studies may have focused their testing efforts on nationally available brands (e.g. Nongfu, Wahaha) that are sold across China and that are produced in multiple regional bottled water facilities.

As noted above, most of the eligible studies with extractable data in our review did not provide specific average concentrations and associated measures of variance (e.g. mean and SD) when reporting the results of analyses of microbiological and chemical parameters. Rather, most studies presented results only in terms of the passing rate, and we assumed that study authors were making these determinations (i.e. the proportion of samples in compliance) based on the relevant bottled water standards at the time of sample collection and/or study publication. Consequently, we were not able to assess the degree to which samples were not in compliance (i.e. for non-compliant samples we could not discern whether they fell just below, or markedly below, the standards). The lack of specific concentration data also limited our ability to compare results to specific standards, or conduct many of the subgroup analyses we pre-specified in our protocol. Likewise, for our meta-regression analyses, we were unable to include some variables hypothesized to be relevant because relatively few studies reported such data.

The limited number of eligible health outcome studies, and the nature of the data reported, prevented meaningful interpretation of results with regard to health impacts associated with bottled water consumption. Relatedly, we were unable to adequately quantify the extent of potential publication bias generally—i.e. we do not know how many studies with results on bottled water contamination may not have been published due to the nature and direction of their findings.

Finally, in our protocol we pre-specified that we would use the Grading of Recommendations Assessment, Development and Evaluation approach to assess and compare the degree of bias in eligible studies. However, because we found relatively few health-focused studies, and due in part to limitations based on the nature and extent of the available reported data, we chose to instead use an index-based approach for ROB.

More broadly, due to the extensive nature of this review it was beyond the scope of this paper to report summary findings for all the microbiological and chemical parameters for which we extracted data. We encourage interested readers to consult the SM excel data file should they wish to view or analyze results for less-commonly-reported parameters or otherwise explore the data we extracted for this study (available online at stacks.iop.org/ERL/17/013003/mmedia ).

5. Conclusions

Included in the United Nation's 2030 Agenda for Sustainable Development is Sustainable Development Goal 6.1: ' By 2030, achieve universal and equitable access to safe and affordable drinking water for all ' [ 243 ]. Increasing consumption of bottled water and bottled water contamination are not issues unique to China, but China is unique in that, unlike most other countries, there exists a large body of published research on bottled water quality.

Overall, we observed that the vast majority of bottled water samples tested across the 625 reported studies from the 216 eligible publications for which we were able to extract data were in compliance with China's relevant bottled water standards. Over the period from 2005 to 2015, we also observed evidence of relatively stable or increasing (positive) overall trends in the proportions of samples reported to be in compliance with relevant bottled water standards. After controlling for other variables via meta-regression analysis, however, these associations were only statistically significant for microbiological outcomes overall, and not for chemical outcomes. We found only nine eligible studies that reported on health outcomes associated with bottled water consumption. Overall, due to the nature of the underlying available data and associated limitations, as well as geographic variation in the number of eligible studies, our findings should not be considered as representative of the general situation in China with respect to bottled water quality over this period.

Increasing reliance on bottled water in China and in other LMICs may serve to further exacerbate disparities in safe water access both directly—via the potential consumption of contaminated bottled water—and indirectly, via its normalization as a primary form of drinking water access. This normalization of bottled water for everyday drinking may in turn undercut efforts to expand and improve public water supply [ 5 ]. Of course, there are settings in China and in other LMICs in which centralized drinking water treatment and piped distribution are not feasible. In many such settings in China, government-run mini-utilities provide filling stations where people pay for and collect treated drinking water in large 19 l reusable bottles at costs much closer to those of piped drinking water than retail bottled water [ 244 ]. This type of kiosk-model for decentralized drinking water provision offers a relatively affordable and sustainable means of providing access to safe drinking water in regions with low population densities or challenging topography or hydrogeology. As noted in this review, one of the key challenges inherent in such an approach is ensuring sufficient disinfection of the reusable bottles between consumption and refill. In settings in China and other LMICs where centralized drinking water treatment and piped distribution is not feasible, efforts should be made to further expand well-regulated decentralized approaches for safe drinking water supply.

Across the world, bottled and packaged water is often accompanied by branding and marketing, promoting the notion that it is healthier and safer than alternative drinking water sources. In China, as well as in other LMICs and HICs, this trust may not always be warranted. The extent of, and impacts from, contaminated bottled water consumption remain poorly understood in both LMIC and HIC contexts—more research is needed on this issue. Given that bottled water will be part of the global waterscape for the foreseeable future, we hope that this work will stimulate more discussion and action on how to better regulate and improve bottled water production and quality. At the same time though, we hope this work will serve to further reinforce the need for LMICs—and HICs—to increase investments in the expansion and improvement of drinking water utilities as a far more equitable and sustainable pathway for providing reliable access to safe and affordable drinking water for all.

Acknowledgments

We are grateful to Li Hongxing at the National Center for Rural Water Supply Technical Guidance (Chinese Center for Disease Control and Prevention, Beijing) for his assistance with results interpretation, replication of primary statistical analyses, and suggestions on earlier drafts of this article. We thank Keith Gilles (UC Berkeley) for his steadfast support of this and other research projects. We also thank Pu Da and Jia Tang (UC Berkeley) for their assistance during one of the semesters of our multi-year work on this project, as well as Stefanie Ebeling and UC Berkeley's Undergraduate Apprenticeship Research Program (URAP). Funding and support for this research was provided by URAP and by UC Berkeley's College of Natural Resources (under Dean Gilles). These funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Data availability statement

All data that support the findings of this study are included within the article (and any supplementary files).

Author contributions

A C designed the study, managed the data extraction, data cleaning, and quality assurance and control, conducted the statistical analyses, created the tables and figures, wrote the first draft of the manuscript, incorporated co-author feedback, and prepared the final manuscript and supplementary material files. Q X, Q S, and X Y assisted with the search strategy design and piloting. J C, Q S, Q X, Y S, X Y, Y G, and J H conducted the search screening, full text identification, review, and data extraction. J C, Q S, and J H conducted extensive data cleaning, quality assurance, and control. J H created the map figures. J M C provided guidance on study design and contributed to results interpretation and the final manuscript. I R oversaw research assistant recruitment, provided guidance on study design, assisted with results interpretation, contributed to drafts, and helped write the final manuscript.

Conflict of interests

The authors declare they have no actual or potential competing financial interest.

Supplementary Excel data

Supplementary tables and figures

Science in School

What are you drinking tap water versus bottled water teach article.

Author(s): Daniela Bergamotti, Paola Semeghini

Which is better: tap or bottled water? Try these activities based on simple analyses, a debate, and a blind tasting to learn about drinking water and encourage sustainable habits.

Water management is crucial to sustainable development, because clean freshwater is essential to human health and well-being. Many prefer bottled water over tap water, but this has a high environmental impact in terms of waste production and pollutants. Many beliefs are related to preconceived ideas rather than to actual experiences or product characteristics: in most EU countries, tap water is controlled, safe to drink, and usually tastes good.

These activities aim to determine students’ views on the topic and influence changes in water consumption and perception. They will increase their knowledge and trust of distributed drinking water and consider the overconsumption of plastic bottled water.

Curriculum links

• chemistry topics: pH, acids and basis (Lewis theory), group 2 metal ions, complexation reactions, solution preparation and concentration, titration technique and principle of the method, pH indicators;
• earth sciences: composition of limestone sedimentary rocks;
• biology: water as a source of mineral salts, physiological effects, osmotic pressure in cells.

We devised the following activities for students aged 16–19. They are also suitable for ages 14–16 if there is less emphasis on titration methods and chemical reactions.

Activity 1: Introduction to drinking water

Firstly, students are given some background information on types of drinking water and invited to do some research on the drinking water in their area.

This activity involves 1 hour of introduction and 2 hours of homework.

• Introduction on water management ( Drinking water infosheet )
• Internet access for research
• Information on/plan of the local water system and water quality (guided visits to water plants are strongly recommended to acquire on-site knowledge of distributed water)
• To-do list ( Local water task sheet )
• Presentation evaluation rubric
• After an introduction on water management and uses (1 h), the students are divided, depending on where they live, into groups of two to four.
• Based on water certificates of analysis (available from the local water utility website) and school science texts, they should prepare a short PowerPoint presentation, following the to-do list on the Local water task sheet . This should include a plan of the area, with a description of the water origin (spring, ground water, or surface water) and its path from source to tap.
• A comparison of the hardness values in different areas influenced by geological features can be made, if applicable.
• The students should assess the values indicated on a water certificate of analysis (e.g., pH, nitrogen content, hardness, etc.) and describe the possible health risks associated with noncompliance.
• The presentations can be marked based on the presentation evaluation rubric .

Activity 2: A debate on tap water versus bottled water

To explore different types of drinking waters and the consequences of our consumption habits, students conduct research and then run a class debate on tap water versus bottled water.

As an alternative, the debate can be left until after Activities 3 and 4, as a consolidating activity at the end.

This activity takes about 3 hours: 1 hour of introduction and research, 1 hour to prepare arguments, and 1 hour for the debate.

• Materials from reliable resources
• Parameters for discussion and debate rules ( Debate task sheet )
• Debate evaluation rubric
• 1 projector or digital board
• Students should be provided with articles and web materials from official sites or publications (e.g., WHO guidelines, Ministry of Health guidelines, data published on the local water company’s website, medical and research associations, articles on environmental issues) that they can integrate with other sources considered to be reliable. See the supporting material for suggested parameters to consider.
• The class is divided into two teams (chosen at random), each supporting one of the motions (tap water or bottled water). Each student should take one parameter (see the Debate task sheet ; make sure all are covered), examine the sources, do their own research, and prepare two sentences to argue their case and one sentence to argue against possible points made by the opposition.
• In the classroom, each team should prepare a list of arguments and counterarguments to ensure that all participants can provide a contribution to the discussion.
• Before the debate, the teacher checks that every argument is based on reliable sources and includes significant and well-documented data or scientific information.
• In the debate, the sides speak in turn. All participants must make a statement. Each speaker has a specified amount of time to speak (approx. 2 minutes) and present arguments and counterarguments (e.g., tap water can taste (smell) like chlorine – to remove chlorine, place a jug of water in the fridge for a few hours before drinking it).

The argumentation skills of each participant, in terms of presentation and content, can be evaluated using the debate evaluation rubric .

After the debate, the class can discuss what they’ve learned. Invite students to share things they didn’t know before or found surprising. Will this affect their drinking habits?

Activity 3: Determination of total hardness in water

Students can analyze their home/school tap water or marketed bottled waters.

For tap water, they should compare the analytical results with the certificates of analysis provided by the local water company; for bottled water, they should compare them with those shown on the labels.

The determination of the total hardness in water is made by titration with ethylenediamine tetraacetic acid (EDTA), which forms colourless stable complexes with Ca 2+ and Mg 2+ ions at pH = 9–10. These ions are naturally present in water due to minerals that dissolve as water passes through soil and rocks.

To maintain the pH of the solution at 9–10, a buffer solution (NH 4 Cl + NH 4 OH) is used. The indicator Eriochrome Black T (EBT) changes colour when these two ions are completely complexed by EDTA.

In addition to the hardness test described here, other tests can be proposed, depending on time and instrument availability, such as:

• calcium and magnesium ion concentrations (atomic absorption)
• calcium salts (flame test)
• bicarbonate concentration (water alkalinity titration)
• microbial analysis of total coliforms (faecal contaminants – reference value: 0 colony forming units (CFU) per ml)

This activity takes about 2 hours. Time is also needed for preparing solutions and equipment (1 h; this can be done by the teacher or technician).

Safety notes

Wear lab coat and gloves

Materials (per group)

• 50 ml burette (+ support)
• 100 ml graduated cylinder
• 250 ml conical flask
• 100 ml beaker
• Glass funnel
• 0.01 M sodium EDTA solution
• Stainless-steel spatula
• Buffer solution, pH 10 (NH 4 Cl + NH 4 OH)
• The provided Water-hardness scale
• Split students into groups of two to four. Assign each group a water sample (tap, distilled, filtered, bottled).
• Fill the burette with 0.01 M EDTA sodium solution (titrant).
• Measure 100 ml of water (sample) into a 250 ml conical flask.
• Add a small amount (a few crystals) of EBT powder (indicator): the solution in the conical flask will turn a rose–violet colour.
• Titrate with sodium EDTA solution until the colour changes to light blue without violet shades.

• What do you observe when the indicator is added to the water + buffer solution?
• What do you observe when a small amount of EDTA is added to the solution? (The colour does not change; it forms colourless stable complexes with Ca 2+ and Mg 2+ ions, which are naturally present in water.)
• Why does the solution turn blue when an extra volume of EDTA is added? (Because all Ca 2+ and Mg 2+ ions have been complexed by EDTA.)
• Calculate the total hardness in French degrees (F°; not to be confused with degrees Fahrenheit!) as mg/l of calcium carbonate (CaCO 3 ) according to the following formula:

1 ml sodium EDTA solution (0.01 M) = 1F° = 10 mg/l CaCO 3

• Classify water as very hard, hard, moderately hard, medium, soft, or very soft: values can change according to local laws, but should be between 10 and 50F°.
• Compare the value with that shown on the label (bottled water) or certificate of analysis from the local water company (tap water).

Units of water hardness

There are a number of different common official measurement units for hardness: [ 1 ]

– Parts per million (ppm) is usually defined as 1 mg/l CaCO 3 . It is equivalent to mg/l without a specified chemical compound.

– French degree (°F or f): 10 ppm or mg/l CaCO 3 . Lowercase f is often used to prevent confusion with degrees Fahrenheit.

– Degree of general hardness (dGH) or German degree (°dH, deutsche Härte): 10 mg/l CaO, equivalent to 17.85 ppm or mg/L CaCO 3 .

– Clark degree (°Clark) or English degrees (°e or e): one grain (64.8 mg) of CaCO 3 per imperial gallon (4.54609 litres) of water, equivalent to 14.254 ppm or mg/l CaCO 3 .

– US degree (gr/gal): a grain CaCO 3 /gal (US gallon = 3.78541 litres), equivalent to 17.118 ppm or mg/L CaCO 3 .

• Does your result match with theoretical values?
• If not, what could be the reasons (e.g., old or ill-maintained pipes, presence of a water softener)?
• If yes, could you form a hypothesis about the origin of water under survey (bottled or distributed water, surface or groundwater, geological characteristics of the catchment area)?
• How do you measure hardness in French degrees? (By measuring the volume in ml of EDTA added under the method conditions.)
• How do you measure hardness in mg/l expressed as CaCO 3 ? (By multiplying the value in French degrees by 10.)

Activity 4: Blind tasting of water

Research shows that tap water is just as safe as bottled water and is often not significantly different in taste. Tap water is generally a better option, since it has a much lower environmental impact and costs considerably less.

This activity is useful to work out common perceptions around the topic and discuss water-drinking habits. The duration depends on the number of participants in the blind-tasting session (at least 50 are required for statistically significant results).

Bottled waters should be selected to include a highly advertised luxury brand, to show how price and advertising do not have a significant impact on taste preferences.

If the tap water is very hard and/or does not taste so good, it can be replaced with filtered tap water.

• 3 glass bottles/jugs
• Paper or compostable coffee cups
• 2 types of bottled water (hardness: 4–8 °F and 20–25 °F)
• Paper for labelling each bottle/jug
• Blind-tasting questionnaire
• Encourage the students to come up with their own questions for the questionnaire. The provided questionnaire can be used as a template.
• Fill up the bottles: each bottle should be filled with a different type of water.
• Line up the bottles and arrange the cups on a table.
• Place a numbered/coloured slip of paper next to each bottle.
• Have someone who is not participating in the test pour the different types of water into three separate cups for each participant. Ideally the cups should be labelled with the same number/colour as the corresponding bottle.
• The participants should take a sip from each cup and fill in the questionnaire to express their perceptions of the three waters included in the taste test, answering the following possible questions: What type of water do you think it is? How would you describe its taste? Do you like it? Can you taste any flavourings? What was your favourite water? Why?

The tasting results can be statistically processed (e.g., test results in terms of number of voters, % assigned to each type of water (pie chart), and choice motivations) and collected in a poster or digital presentation.

They can be shared and made public through the school website, social media, and/or a poster exhibition encouraging the benefits of sustainable drinking habits.

In many blind taste tests, participants find bottled water to be indistinguishable from tap water, and tap water is often the favourite one, showing that many beliefs are related to preconceived ideas rather than to actual experiences or product characteristics.

The MULTIPLIERS project

This teaching and learning activity was developed as part of the MULTIPLIERS Horizon 2020 project by Iren, an Italian multiutility company and one of the MULTIPLIERS partners, through its educational department Eduiren and in cooperation with the Pascal upper secondary school in Reggio Emilia.

MULTIPLIERS promotes open schooling across Europe to make science more meaningful and directly relevant to real-world challenges. By connecting students with universities, informal education providers, museums, local associations, industry, civil society, policymakers, media, and other actors in authentic learning settings, the project promotes competence development in socioscientific issues that have a direct impact at the local level and beyond. The ultimate goal is to foster social transformation by enabling students to act as “knowledge multipliers”, sharing their learnings and findings with their wider communities.

MULTIPLIERS has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 101006255.

Learn more about the project: https://multipliers-project.org/

[1] The Wikipedia entry on how to measure hard water: https://en.wikipedia.org/wiki/Hard_water#Measurement

• Learn how to spot pseudoscientific fake news in the media: Domenici V (2022) Fake news in chemistry and how to deal with it . Science in School 59 .
• Read about the impacts of meat consumption and the development of lab-grown substitutes: Noble M (2023) From Petri dish to plate: the journey of cultivated meat . Science in School 63 .
• Read an article about the environmental effects of food packaging: Barlow C (2022) Plastic food packaging: simply awful, or is it more complicated? Science in School 56 .
• Explore the water footprints of the foods we eat: Kelly S (2020) Do you know your water footprint? Science in School 50 .
• Teach about freshwater with these low-cost experiments: Realdon G et al. (2021) Watery world – hands-on experiments from Earthlearningidea . Science in School 54 .
• Investigate the properties of so-called superfoods: Frerichs N, Ahmad S (2020) Are ‘superfoods’ really so super? Science in School 49 : 38–42.
• Teach about water quality and analysis: Al-Benna S (2014) Become a water quality analyst . Science in School 29 : 35–40.

Cutting-edge science: related EIROforum research

Seed extracts from the Moringa tree have been used for centuries to help purify water in regions where clean water is not available. Researchers at the Institut Laue–Langevin ( ILL ) and the European Synchrotron Radiation Facility ( ESRF ) have used neutrons and X-rays, respectively, to identify and characterize key proteins underlying the unique water purification properties of Moringa seeds. This information may allow better use of this abundant resource for sustainable water purification.

Paola Semeghini graduated with a degree in pharmaceutical chemistry from Modena University and worked for several years in the pharmaceutical industry. Since 2011, Paola has been a chemistry and scientific laboratory teacher at IIS Pascal, an applied science upper secondary school in Reggio Emilia, Italy, focusing on competence-based education and experiential learning.

Daniela Bergamotti manages the educational activities and projects promoted by Iren, a multiutility company operating in the waste, water, and energy sectors, in the Italian region of Liguria. Eduiren, the company’s educational division, is committed to building relationships with schools and communities, using a creative and inclusive approach to spread a culture of sustainability and achieve concrete changes.

Full link for United Nations statement: https://www.unep.org/interactives/beat-plastic-pollution/?gclid=EAIaIQobChMIm7eEuP6SgAMViX5MCh1XWQNZEAAYBCAAEgKFR_D_BwE 

The United Nations Environment Programme (www.unep.org) highlights the severe environmental, social, economic and health consequences of our addiction to single-use plastic products. Hence, this article, encouraging teachers to get their students to think about the pros and cons of using bottled water versus tap water is very timely. The article is also very balanced with opportunities to consider when bottled water may be essential.

Within the article there are different activities that teachers could adapt for different classes, including using internet research and the generously provided material provided with the article to understand the processes used to deliver clean tap water, an organised debate, a titration to determine water hardness and organising a blind water tasting test. Some of the ideas could also be used with a science club or to provide inspiration for individual or team science projects.

This article has many curriculum and cross-curricular links.

Curriculum topics include: critical analysis of data; fair testing; practical analysis skills; practical titration skills; practical titration skills; pH and pH indicators, acids and bases; metal ions; chemistry of limestone;

Cross-curricular links include:

Geography – availability of clean drinking water in different countries; the geography of rivers and the ‘rivalry’ for river water.

Earth Sciences – limestone sedimentary rocks;

Biology – biological uses of water; osmosis, water as a solvent e.g. for mineral ions

Suggested discussion questions:

• Is bottled water better than tap water?
• Why is ‘clean freshwater essential to human health and well-being’?
• What is the difference between ‘ground water’ and ‘surface water’?
• Why is bottled water seen by many as preferable to tap water?
• What are the main steps in water treatment before water arrives at your tap?
• What are the important considerations in carrying out a blind tasting of different waters?

Sue Howarth, UK

Supporting materials

Drinking water infosheet

Presentation evaluation rubric (PDF)

Presentation evaluation rubric (doc)

Local water task sheet

Debate evaluation rubric (PDF)

Debate evaluation rubric (doc)

Debate task sheet

Water hardness scale

Blind tasting questionnaire

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Health beliefs about bottled water: a qualitative study

Lorna a ward.

1 Medical Student, University of Birmingham, Birmingham, B15 2TT, UK

Owen L Cain

Ryan a mullally, kathryn s holliday, aaron gh wernham, paul d baillie, sheila m greenfield.

2 Primary Care Clinical Sciences, University of Birmingham Medical School, Birmingham, B15 2TT, UK

This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0 ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Associated Data

There has been a consistent rise in bottled water consumption over the last decade. Little is known about the health beliefs held by the general public about bottled water as this issue is not addressed by the existing quantitative literature. The purpose of this study was to improve understanding of the public's health beliefs concerning bottled mineral water, and the extent to which these beliefs and other views they hold, influence drinking habits.

A qualitative study using semi-structured interviews, with 23 users of the Munrow Sports Centre on the University of Birmingham campus.

Health beliefs about bottled water could be classified as general or specific beliefs. Most participants believed that bottled water conferred general health benefits but were unsure as to the nature of these. In terms of specific health beliefs, the idea that the minerals in bottled water conferred a health benefit was the most commonly cited. There were concerns over links between the plastic bottle itself and cancer. Participants believed that bottled water has a detrimental effect on the environment. Convenience, cost and taste were influential factors when making decisions as to whether to buy bottled water; health beliefs were unimportant motivating factors.

The majority of participants believed that bottled water has some health benefits. However, these beliefs played a minor role in determining bottled water consumption and are unlikely to be helpful in explaining recent trends in bottled water consumption if generalised to the UK population. The health beliefs elicited were supported by scientific evidence to varying extents. Most participants did not feel that bottled water conferred significant, if any, health benefits over tap water.

Demand for bottled water has consistently increased during the last decade, making bottled water the fastest growing segment of the non-alcoholic beverage market worldwide [ 1 ]. Consumption of bottled water in the UK rose from 1415 to 2275 million litres between 2000 and 2006 [ 2 ] and in 2003, UK consumers spent £1 billion on bottled water [ 3 ]. Indeed, for some of these consumers, bottled water has become a complete substitute for tap water [ 4 ].

However, these increases, in the UK at least, fly in the face of improving tap water quality over the last 10 years [ 5 ] and are even more surprising given that bottled water can cost on average 500–1000 times more per litre than tap water [ 6 ].

In contrast, recent media reports suggest a new-found scepticism about bottled water. A recent BBC Panorama documentary highlighted the environmental cost of bottled water [ 7 ]. There are also reports of the general public's reticence to accept the rising cost of bottled water on the basis of health claims [ 8 , 9 ].

Literature review

No qualitative studies address public beliefs about bottled water in the English language peer-reviewed literature. A small number of quantitative studies have focused on this general area, although none have been carried out in the UK.

A discussion paper published in 2006 by Doria [ 1 ] reviewed the literature and identified dissatisfaction with tap water taste, odour and sight, and health concerns over tap water, as the major motivating factors for choosing bottled water. It also highlighted the lack of peer-reviewed literature on the reasons for choosing bottled water and the need for more research. In another discussion paper published on behalf of the Worldwide Fund for Nature (WWF) in 2001 [ 6 ], although there was some reliance on non-peer reviewed literature, similar suggestions were made indicating taste, safety and health issues to be the main motivating factors to buy bottled water.

The most recent original peer-reviewed research was an extensive quantitative study produced by the American Waterworks Association (AWWA) published in 2005 [ 10 ], a telephone survey of 2268 American residents. The findings of the study were that bottled water drinkers were satisfied with the quality and safety of tap water and suggested that most bottled water drinkers saw bottled water as a "luxury item", and not something that they purchased due to any perceived problems with their domestic water supply. It also identified taste, safety and healthiness as motivating factors in the choice to purchase bottled water as an alternative to tap water. However, whilst this study highlighted health beliefs as an important factor, it failed to explore what these consumers' health beliefs actually were.

A smaller telephone-interview-based quantitative study of residents of Quebec [ 11 ] concluded that taste, rather than safety, was the most important motivating factor for people buying bottled water. This study also noted consumer dissatisfaction with tap water. Research conducted in France in 1989, 1995 and 2000 [ 12 ] supports this, showing consistently that taste was a more frequently given reason for drinking bottled water than reasons concerning health and tap water risk.

In contrast, concerns over tap water safety and the consumption of bottled water as a substitute for other beverages were the motivating factors in over 80% of the 1600 Americans interviewed in an older study by the AWWA published in 1993 [ 13 ].

A large laboratory-based study by Olson [ 14 ] is often referenced in the literature. However, the claim made by the paper that "It is absolutely clear, therefore, that a leading reason for the explosion in bottled water sales is the public perception, fuelled by heavy industry advertising, that bottled water is pure and pristine, and thus a healthier choice than tap water" was not based upon any published research and was merely an expression of the author's opinion.

Existing quantitative literature broadly identifies health, taste, odour and sight as reasons for consumer preferences for bottled water. Health beliefs therefore seem to be an important factor in choosing to drink bottled water. However the existing research is not explicit about what these beliefs are and tends to take a comparative approach in identifying why the consumer might choose to drink bottled water as an alternative to tap water. Hence the health reasons given are generally beliefs concerning unfavorable properties of tap water. Previous research has been based in the USA, Canada and France and although these studies do seem to complement each other in the themes that arise, they concern different populations with different water supplies. It is unclear how generalisable the findings are to the UK.

This study was therefore designed to discover more about individuals' beliefs associated with bottled water and the perceived health effects of bottled water, in a UK setting. We also aimed to determine whether these beliefs were important factors in any motivation to drink bottled water and hence their possible contribution to the growth of the bottled water market.

Recruitment of participants

All participants in this study were users of the Munrow Sports Centre on the University of Birmingham campus. The majority of this sports centre's users are staff and students at the University of Birmingham, with a small number of members from the local community. This cohort was targeted based on the assumption that sports centre users might be more likely to have developed health beliefs than the general public. Recruitment occurred on six separate occasions at varying times of the day on different days of the week in January and February 2008 at the entrance to the sports centre. Every user entering or leaving the building during these times was approached.

Potential participants were briefed about the nature of the study by the researchers and after a provisional agreement to participate they were invited, by a standard e-mail on two occasions, to attend an individual interview at a time and place convenient to them. This ensured a relaxed atmosphere during the interview, with ample time in which to explore the interview themes. Each person who responded to the e-mail invitation was interviewed with no exclusions. Recruitment ended when all of the researchers agreed that no new themes were emerging from the content analysis and that data saturation had been reached.

Data collection

Semi-structured interviews were deemed the most appropriate method of data collection for this topic for which there is a lack of previous research. Semi-structured interviews use some pre-determined, mainly open ended questions, to help define the area to be explored, but are flexible and allow the interview to diverge from this guide in order to pursue ideas in more detail [ 15 ].

A pilot study with four interviews was conducted, which informed the development of a basic interview schedule constructed from previous research findings in this area. The modified interview schedule was subsequently used for all of the interviews in this study. It prompted participants to discuss their habits of bottled water consumption, perceived differences between tap and bottled water, personal beliefs about bottled water and the beliefs that others hold about bottled water. It was emphasised that the term 'bottled water' referred to still bottled water purchased from a supermarket, shop or vending machine, and not sparkling water, or tap water in a bottle.

The interviews were conducted by six of the researchers (LW, OC, RM, AW, KH, PB) who were briefed in the techniques of qualitative interviewing by SG and practiced these techniques informally before data collection began. Two researchers were present at each interview, one conducting the interview and one operating the recording equipment. The interviews were recorded using digital recording equipment and later transcribed verbatim.

In total, 23 interviews were conducted between January and March 2008 in the participants' own homes, places of work, or at the University of Birmingham Medical School. The length of interviews ranged from 5 minutes 52 seconds to 22 minutes 12 seconds, mean length 12 minutes 17 seconds. The variation in length of the interviews was not related to the researcher conducting the interview. Instead the variability is mainly attributable to differences in participant knowledge and convictions about bottled water. The shortest interview resulted from the inclusion of one participant for whom English was not their first-language and hence they found it difficult to give extended answers to the questions.

Data analysis

A qualitative content analysis using elements of grounded theory was employed to analyse the transcripts. The inductive process of identifying themes from the data collected, rather than applying top down a priori categories, was appropriate given the paucity of previous research exploring public perceptions of beliefs about bottled water [ 16 ].

The data was broken down into meaningful phrases or sentences using open coding. Categories were then identified and used to find the central themes that emerged from the data. In line with the grounded theory approach, these themes were not the same as those in the interview schedule but arose from the coding process. Investigator triangulation ensured trustworthiness of the analysis. The data was divided between the team with two coders for each transcript. Regular meetings of the team gave room for discussion about all levels of coding, particularly about data inconsistent with the evolving categories.

Ethical considerations

This study did not require ethics committee approval. Participation was voluntary and participants were free to withdraw at any time. Participants were assured that confidentiality would be maintained. Before the interview began, the purpose of the study was explained again and informed verbal consent for participation in this study was obtained.

Socio-demographic information about each of the participants was collected at the beginning of each interview [see Additional file 1 ]. Of the 23 participants, there were 19 females and 4 males, aged between 18 and 52 years and all were currently living in the West Midlands Region. In terms of ethnicity the majority were White British, although those of White Irish, White Other and Asian British backgrounds were also represented. Eleven of the participants were students at the University of Birmingham, ten were employed by the University of Birmingham and two were employed outside of the University.

Participants were classified into three groups based on their reported average bottled water consumption in litres per week. The majority of participants in this study, 19 participants, were 'limited consumers' of bottled water and drank 0.5 to 3.5 litres per week. Two participants were 'consumers', drinking more than 10 litres each per week. Two participants were 'non-consumers' and never drank bottled water.

Data analysis revealed two main themes encompassing participants' beliefs about bottled water; health beliefs and environmental concerns. A third theme, factors that motivate participants to purchase bottled water also emerged [see Additional file 2 ]. Selected quotes are presented to illustrate the different subcategories that arose within these themes.

Health beliefs about bottled water

Most participants believed that compared to tap water, bottled water conferred additional health benefits. Bottled water was considered to be a "healthy option" even if participants were unsure as to why:

"Um...well I think it's probably better for you than er...it's probably got good minerals and stuff in it...um...probably better for you health-wise." (P5, Limited consumer)

"I mean I know it's good but I'm not sure why it's good." (P11, Limited consumer)

Not only were the majority unsure as to why bottled water might confer health benefits, the nature of these health benefits was generally not specified either. In cases where participants did indentify a specific reason for the health benefit of bottled water compared with tap water, a belief that the minerals in bottled water conferred a health benefit was most commonly cited:

"It has different minerals added, which I assume to have some benefit." (P19, Limited consumer)

Only three participants gave any other specific health benefits. One participant believed that the bottled water could relieve symptoms of myalgic encephalopathy (M.E.), in the same way that filtering water seemed to provide some benefit to a family member:

"Err...it started off with filter water. We used to buy filters and just filter all the tap water and it got too much hassle so we went onto bottled water and we went to filter water because my cousin got M.E. and they found that filtering his water pretty much cured all his symptoms of M.E. So when he...they started doing that we then started doing it as well and then." (P6, Limited consumer)

A second participant believed that bottled water was " better for babies " (P15, Limited consumer), and the third person who ascribed a specific health benefit felt that bottled water could improve bone strength. However, as with many participants, they lacked conviction in their belief and were unable to explain their reasoning:

"Um...er...it makes your bones stronger...I have no idea to be honest." (P5, Limited consumer)

The majority of participants associated bottled water with having fewer impurities than tap water, and were more likely to trust the quality of bottled water than tap water:

"They take out all the impurities don't they? And filter it all out." (P16, Limited consumer)

"It's a bit purer than what comes out of the tap." (P14, Consumer)

Conversely, only two participants believed that tap water in the UK had either higher quality standards than bottled water or fewer impurities:

"The quality control on tap water is much higher than on bottled water." (P7, Limited consumer)

"There is all sorts of erm...dubious erm...ingredients in the bottled water." (P12, Limited consumer)

Despite their beliefs about the purity of bottled water, most participants expressed doubts as to the extent of the health benefits of bottled water compared with tap water:

"I really don't think there is much difference between the two to be honest." (P16, Limited consumer)

"If the water quality of the water coming out of the tap is good I'm not sure there are any health claims that can be justified with bottled water" . (P12, Limited consumer)

These views were not mutually exclusive with beliefs about health benefits, indeed most participants believed that bottled water did have health benefits, but that these benefits were negligible:

"I suppose there must be some benefit I have no idea like you know what percentage of your recommended daily allowance it is...I certainly wouldn't drink it for minerals that otherwise I wouldn't get." (P8, Limited consumer)

A minority of participants consistently denied any health benefits:

"I don't think there is anything inherently better about bottled water than tap water." (P1, Limited consumer)

A minority of participants expressed concerns that drinking bottled water was detrimental to health. One subject believed that the " actual process of putting it into the plastic bottle " (P21, Limited consumer) might impair the purity of the water and have a negative impact on consumers' health. Several other participants suggested a link between the plastic used for packaging and cancer. However, these concerns were about the repeated refilling of empty bottles with tap water rather than being about bottled water per se :

"I have heard concerns about plastics and the chemicals from plastics getting into water and links to cancer." (P19, Limited consumer)

"What I've heard it did say something about the plastic starting to break down and something about it being able to cause cancer and as soon as anyone says something about cancer you'd think." (P11, Limited consumer)

"Um...it was about like the whole cancer of using the same bottle over and over again, it breaks down or something like that." (P22, Limited consumer)

Environmental concerns

A number of participants believed that it was "not eco-friendly" (P18, Non-consumer) to use bottled water and expressed concerns about bottled water's "carbon footprint". Some were concerned with the environmental impact of the plastic bottles:

"I prefer to drink tap water because er it's got no packaging." (P15, Limited consumer)

For others, the concern was with the environmental impacts of transporting the water:

"I try to be green (laughs) and buy local mineral water...I try to buy something from the UK so it's not flown over." (P4, Limited consumer)

When asked the reasons that may deter others from drinking bottled water, one person highlighted how topical the environmental issues were, by noting the impact of a recent BBC Panorama documentary:

"Because they'll have watched programmes like the Panorama programme where they see the actual result of all this bottled water coming from all these countries where people can't actually get clean drinking water because we're stealing it all to have in our fancy bottles um and I dunno possibly because like we are here our we have filtered mineral water we don't have bottled water for staff ." (P17, Non-consumer)

Motivating factors

Beliefs about the health benefits of bottled water emerged as a motivating factor influencing participants' decisions to drink bottled water in only a minority of cases, participants 5 and 11, both limited consumers:

"Obviously mineral water has the extra natural goodness in it whereas tap water they probably add things to it to make it cleaned up." (P11, Limited consumer)

Interviewer - "Ok, and if we gave you a glass of tap water and a glass of mineral water and asked you to drink only one of them, which would you drink and why?"

Participant- "Um, the mineral water because it's gonna have more minerals in, it's gonna be fresher." (P5, Limited consumer)

Others chose to drink bottled water because of concerns over the safety of tap water:

"I'd probably choose the mineral water...because I think I have more confidence that it's been purified than the tap water." (P19, Limited consumer)

However, most people were of the opinion that the tap water was fit for purpose and nobody expressed the view that they had reservations about the safety of tap water that were strong enough to prevent them from using it:

"Tap water in England is fine, perfect" (P9, Limited consumer)

Analysis revealed a number of other motivating factors that were unrelated to health beliefs. Convenience, taste and cost were almost universally important. The most commonly cited reason for purchasing bottled water was convenience:

"When I go away to races I might not have a bottle with me so I'd buy some water..." (P3, Limited consumer)

"The only time I drink bottled water would be if I was out somewhere and wanted some water" (P7, Limited consumer)

Several participants described how they would buy bottled water as they preferred the "taste" of it to tap water:

"Well for me mineral water tastes of nothing...ha...cold nothing, I think tap water has some kind of taste to it..." (P4, Limited consumer)

Participant 16 summarised the general consensus regarding the cost of bottled water:

"If it was a choice to buy [bottled water] and not to buy it and it was drinkable from the tap then [they] would go for the tap water...it is mainly down to money." (P16, Limited consumer)

Other factors included preference over other soft drinks, influence of the media, influence of marketing and advertising, bottled water as a status symbol or as a luxury item and re-use of the bottle as a container for tap water.

This study found that most people did hold health beliefs about bottled water, but that in the majority of cases these health beliefs were not strong motivating factors for purchasing bottled water. Other factors such as convenience, cost and taste emerged as far more important reasons for any preference for bottled water. In addition, most participants felt that there was not a significant health benefit in drinking bottled water compared to tap water. From this, it is unlikely that the recent surge in bottled water consumption is due to beliefs about health benefits associated with bottled water.

These results are important because until now, no qualitative studies have been conducted exploring public perceptions about bottled water and the factors that motivate people to buy it. The findings complement previous quantitative studies that have been conducted in this area [ 10 - 13 ]. The qualitative approach of this study allowed for a deeper exploration of the themes that were used in the quantitative data, and also gave room for new themes, not covered in the top-down approach of the quantitative studies, to emerge.

Convenience was a major motivating factor for buying bottled water, and one that has not been covered in previous quantitative studies. This may be because the 'top-down' approach of questionnaire design did not include convenience as a category. It seems obvious that people who would normally drink tap water would be motivated to buy bottled water when tap water is unavailable, for example in a shopping centre, or at the cinema. 'Convenience' is a motivating factor determined by the consumer's situation, not by the consumer's beliefs about bottled water.

Participants expressed health beliefs about bottled water that could be categorised as general health benefits or more specific health benefits. Although this is the first study to identify health beliefs about bottled water, the 2006 review by Doria suggests that there is much interest in the subject in both the grey literature and in the peer-reviewed literature, where unsupported claims regarding consumer beliefs are easy to find [ 1 ]. For example, Petrie and Wessely claim that bottled water is seen as a "natural antidote" to all the things bad for their health due to modernity [ 17 ].

A major emergent health belief was that most people were satisfied with the quality of their tap water supply and that it would not pose an adverse risk to their health. This is consistent with the data from Mackey et al [ 10 ], which demonstrated high tap water satisfaction, even in groups who drank bottled water in preference to tap water.

Interestingly, whilst the majority of participants expressed the belief that bottled water has health benefits of some kind, paradoxically these same participants also stated that the health benefits of bottled water are negligible or non-existent. This perhaps reflects confusion in the general public, as suggested by Olson [ 14 ], in that they only half-believe the marketing promoting health benefits of bottled water.

Such marketing might also explain why many participants, whilst able to state health beliefs regarding bottled water, were unable to explain or qualify these. The ability of marketing companies to create demand for bottled water "through the skilful use of language and image" has been discussed in a review of American culture [ 18 ]. This review suggests that in the public mind, purity, naturalness and healthiness are associated with bottled water through the specific marketing strategies of bottled water companies. The following statements taken from the websites of two leading brands seem to support this suggestion:

"You want the best for your body and we've got it. Taste and feel the volvic difference, pure and natural...courtesy of Mother Earth" [ 19 ]

"Replenish your body with the purity of Evian" [ 20 ]

There was some discrepancy between the specific health benefits participants believed bottled water to have and reality. Participants often felt that bottled water had an increased mineral content compared to tap water and that this conferred a health benefit. An extensive study conducted in the USA by Azoulay et al [ 21 ] compared the mineral content of tap water in various areas and a number of commercially available American and European bottled waters. Some brands of mineral water do indeed have a higher mineral content than tap water, which was found to be generally low in minerals, and were recommended as important dietary sources of calcium and magnesium. However, there is a considerable difference between bottled water brands, which no participant in our study seemed to be aware of.

Furthermore, in the USA study, some mineral waters were actually found to have a lower mineral content than the tap water supply, so the belief that all bottled waters are superior to tap water in terms of mineral content is incorrect. Although the study in question was conducted in the USA, the situation is likely to be similar in the UK. Moreover, whilst this study identified that some bottled waters provide a significant amount of the recommended daily intake for magnesium and calcium, none of these brands matched those that our participants drank. Of these, the preferred brands expressed all fell into the low mineral content classification of bottled water except for one, which was classified as moderate mineral content [ 21 , 22 ].

It is also important to remember that these minerals can be obtained from other sources in the diet, so the health benefits of the minerals contained in bottled water are not exclusive to this source. In addition, research shows that drinking waters with low mineral content does not lead to mineral deficiencies [ 23 ].

Where participants were able to give specific health benefits of bottled water we were not able to find supportive evidence in all cases. One participant believed that the symptoms of M.E were ameliorated by bottled water, which is something that existing literature does not appear to support. However, another participant mentioned that they felt that bottled water was especially benficial for babies. Despite finding no recommendations for this practice, we were able to find one study which suggested that choosing a mineral water with low sodium content may be useful in preparing formula milk because a hyperosmolar diet has been linked to hypertension and obesity in later life [ 23 ]. Having said this, no evidence could be found to suggest that tap water was unsuitable for this purpose.

Safety has previously been identified as an important motivating factor for buying bottled water [ 10 - 13 ]. Indeed, this was a theme that emerged in this study. It is worth emphasising again that participants did not feel that UK tap water was unsafe. Indeed the quality of this has continued to increase over the last 10 years [ 5 ], but participants still felt that bottled water was safer and purer when compared to tap water.

Only one participant correctly stated that tap water was in fact subject to more stringent testing than bottled water in the European Union (EU). The 1980 European Directive on natural mineral water outlines standards for these waters [ 24 ]. This became UK law in 1985 [ 25 ]. Under these regulations natural mineral water cannot be sterilised or otherwise treated to destroy microorganisms. Bottled water is not free of microorganisms as some might believe and this has been demonstrated by numerous studies [ 4 , 26 - 28 ].

Although European regulations are considered more rigorous than those in the USA [ 26 ], natural mineral waters are only tested every two months by independent laboratories, compared to tap water which is tested every two days in urban areas [ 5 ]. In addition, quality controls for tap waters are based on 62 parameters, compared to only 26 for mineral waters [ 5 ].

Doria notes that whilst there have been outbreaks of disease attributable to tap water, such as in Sydney in 1998, which led to an increase in bottled water sales, bottled water is not without similar events. The well-known brand Perrier was contaminated with benzene in 1990 and in 2004, Coca-Cola withdrew Dasani, its own bottled water, due to concerns about the levels of a potential carcinogen in the water [ 1 , 29 ].

A number of participants expressed concerns about a link between the plastic container of bottled water and cancer. A carcinogenic substance known as DEHA (di-ethylhexl adipate) is indeed used in the manufacture of PET (polyethylene terephthalate), a plastic used to manufacture most bottled water containers [ 27 ]. However, laboratory studies performed by the US Environmental Protection Agency concluded that leaching of DEHA from the bottle is not harmful to human health [ 30 ]. Although not true, the concerns held by participants about the plastic bottles are not irrational and replicate concerns that other people seem to have. For example, in 2004 a hoax e-mail circulated in the USA, attributed to Johns Hopkins University, suggesting that the plastic used to manufacture the containers for bottled water contained harmful dioxins, which is untrue [ 31 ].

Almost a third of participants expressed concerns over the environmental impact of bottled water. These concerns mirror recent media interest in the subject [ 7 - 9 ]. These concerns included comments about the 'carbon footprint' created by the transport of imported bottled water. A 2006 Earth Policy Institute study found that the British bottled water industry generates about 30,000 tonnes of carbon dioxide per year, which was estimated to equal the energy consumption of 6,000 homes per year [ 32 ].

The environmental impact of the plastic bottles themselves in their production and disposal was also mentioned by some participants. Packaging is generally made from plastics, either polyvinylchloride (PVC) or PET; the latter is becoming widely used as it is easier to recycle than PVC and does not release chlorine when burnt [ 5 ]. In the USA, annual production of PET to meet the needs of the bottled water industry uses around 18 million barrels of oil [ 32 ], which is a finite resource. Although the smaller UK market would mean lower oil use, considering that in 2006/2007, only 58.4% of municipal and 28.6% of household waste was recycled in the West Midlands, participants are probably correct in their concerns [ 33 ].

Limitations

This study has several limitations. Selection bias may have occurred in that the participants in the study had both the time available and the inclination to take part. This might mean that those with particularly strong views on the issue were more likely to volunteer, but this does not appear to have been borne out in our results. Availability bias may have occurred in that the issues surrounding bottled water can quite feasibly change over time and certain factors may become transiently important [ 34 ]. An example would be negative health beliefs about tap water as a motivating factor to purchase bottled water following media reports of contamination of the supply.

The fact that all of the participants in this study had connections with the Munrow sports centre, and the majority were employed by or studying at the University of Birmingham, has implications for the generalisability of the findings of this study. Hence, the results may not be applicable to people who are unemployed or not in full time education, or people who are not sports centre users. Repetition of the study with a sample more representative of the general population may therefore be of value.

Respondent validation may have proved useful since respondents' reactions to emerging findings can help to refine explanations and can strengthen the rigor of thorough qualitative research [ 35 ].

Recommendations

A number of issues arise from this study which may warrant further research. Namely the link between marketing strategies for bottled water and their role in creating health beliefs in the general public. It would also be interesting to see if it is possible to identify people who drink exclusively bottled water and question them about their reasons for this and their health beliefs about bottled water. Such information could then be compared with the results of this study to determine whether people who only drink bottled water are motivated to buy it by the same factors as the participants in this study, and the role of health beliefs within this. Finally, given the lack of knowledge about the purification process and safety of tap water in the UK found by this study, it could be useful to further educate the public with regard to the safety of tap water considering the prevalence of concerns arising that appear to be unfounded.

The participants of this study had a range of health beliefs about bottled water which could be classified as general and specific benefits. Participants also held a number of beliefs about the impact the bottled water industry has on the environment. Although the majority of participants believed that bottled water had some health benefits, these beliefs played a minor role in determining bottled water consumption and are unlikely to be helpful in explaining the recent trends in bottled water consumption. The health beliefs that participants held were supported by scientific evidence to varying extents.

Convenience, cost and taste were more influential factors for participants when deciding whether to buy a bottle of water or not. Most participants did not feel that bottled water conferred significant, if any, health benefits over tap water.

Competing interests

The authors declare that they have no competing interests.

Authors' contributions

SG conceived of the study, provided support and advice to the other authors at all stages and was involved with redrafting of the manuscript. LW, OC, RM, KH, AW, PB were involved with the study design, recruitment, data collection, data analysis and writing of the manuscript. All authors read and approved the final manuscript.

Pre-publication history

The pre-publication history for this paper can be accessed here:

http://www.biomedcentral.com/1471-2458/9/196/prepub

Supplementary Material

Socio-demographic backgrounds of the participants . A table presenting the socio-demographic backgrounds of the participants.

Themes identified in analysis and participants who contributed to these themes . A table presenting the themes identified in the analysis and participants who contribute to these themes.

Acknowledgements

The authors would like to thank all of the participants of this research. They would also like to thank the University of Birmingham and the Munrow Sports Centre for allowing the recruitment of participants on the University campus and the University of Birmingham Medical School for allowing the use of their facilities.

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Bottled water vs tap water

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Journal of Water and Health

Andréa Zhouri

This study presents perceptions of consumers of bottled water in their households in three Brazilian municipalities. Data from interviews were analyzed using the Discourse Collective Subject method. Interviewees spent, on average, the equivalent of 40% of their water bill for the public water supply on the purchase of bottled water. The decision about water consumption in the household was predominantly made by women. Interviewees were particularly concerned with health risks and expressed a strong preference for the safety and organoleptic qualities of bottled water, particularly in cases where the tap water supply did not fully meet the regulated water quality standards. Interviewees were largely unaware of the origin, type, storage, and social and environmental impacts of bottled water. Results highlight the importance of water education efforts among the general population and the key role of women in the processes related to drinking water. The need for gender-specific interven...

Sustainability

lucie ozanne

This exploratory study examines the consumption motivations of those consumers who choose to buy bottled water, while at the same time exploring the perceptions they hold about the potential environmental consequences of their actions. Based upon a sample of sixteen participants aged from 19 to 56, our findings revealed five main themes as to why people purchase bottled water, including: (1) Health, comprising the two subthemes of personal health and cleanliness, (2) the bottle, (3) convenience, (4) taste, and (5) self-image. Our findings also highlighted the perceptions held about the environmental consequences of bottled water consumption and the considerable challenges marketers have to address if they are to persuade consumers to consider alternatives to this consumption practice.

Troy A Belford

Journal of Consumer Culture

Richard R Wilk

hamed biglari

Introduction: Understanding consumer perception of drinking water can contribute to improvements in water management and consumer satisfaction. The aim of this study was to assess the consumer perception of tap water quality and other drinking water sources in Gonabad as a small semiarid city. Methods: This study was performed in autumn and winter 2013. For collection data a researcher-made a questionnaire consisting of nine questions, based on demographic information prepared. Questions were asked for participants to provide information regarding household drinking water usage and patterns, opinion about tap water safety, taste and reasons for purchasing bottled water. For statistical analysis, analysis of variance (ANOVA) using SPSS version 16 was applied in this study. Results: Results showed that demographic variables had a significant relationship with consumer satisfaction (p < 0.05). Office employees, women and poor families had the most satisfaction from tap water quality. Peoples' preferences for tap water, commercial softener, domestic softener, ghanat (a type of underground cistern) and bottled water were 27.8, 19, 27.8, 40.4 and 3.5% respectively. Dissatisfaction from production of foam, unsuitable taste, unacceptable appearance and other problems in tap water was 11.1, 95.6, 27.8 and 0.4% respectively. Consumer reasons for using domestic water softeners are: suitable taste (80%), easy availability (71%), economical (56%) and low health side effects (34%). Conclusion: According to these results it was clear that each consumer group, based on self-condition, prefers using a specific drinking water source.

Suresh Kumar

There are various types of bottled drinking water in Indonesia market. Water is essential for human life. Nowadays, to meet people needs in daily life to drink water, many companies provide bottled drinking water. As this industry growing and more competition happen, the companies have to know the things that influence people to buy the products which are bottled drinking water. The aim of this research is to analyze several factors that influence people buying decision on it, namely brand, quality of the water, and the packaging of the product. Quantitative research was chosen as the methodology, with questionnaires distributed to gain the primary data. The questionnaires were distributed to 300 undergraduate students of President University in Cikarang, West Java, Indonesia. The questionnaires distribution was done in President University's campus and student housing area. Based on the survey result, it is proven that brand, quality of the water, and the packaging of the product influence the respondents' buying decision on bottled drinking water. The companies' owners as well as management have to understand that fact well. Thus, this research result can be used by entrepreneurs who are currently in bottled drinking water business and also for those who want to open the business in this industry.

WIREs Water

Gay Hawkins

Tamar Opher

International Academy of Management and Business (IAMB) Fall Conference Istanbul, Turkey to be held on October 12-14, 2009

Dr. Nazrul Islam

Majority people of Bangladesh are illiterate and unconscious about their health. They are unable to understand the importance of their health. They even do not know the benefits of health precautions which are primarily concerned with food and drinking water. It is identified from the research that the people have some general and specific beliefs on health benefits related to drinking water. The beliefs are bottled water is purer than tap water, health benefits of bottled water are not substantial bottled water is not properly processed, etc. Therefore, people are hardly enthusiastic to buy and consume bottled water. On the other hand, research shows that there are some motivating factors for buying bottled water. These factors are concerned with health benefits, concerns about tap water, convenience, taste, preference over soft drinks, bottle itself, status symbol, luxury item, media, and advertising aspects. Given these observations in mind, this study concentrates only on the beliefs and motivating factors to buy bottled drinking water. This study is only confined among the university students who are studying at the private universities located in Dhaka city. A total of 399 students were interviewed with a structured questionnaire. Both descriptive and inferential statistics were used in analyzing data. For identifying the factors relating to health beliefs and buying decision of bottled water, factor analysis was conducted. Results show that the students give most importance on safety and taste of the bottled water whenever they buy. The other factors include media exposure and reputation of the bottled water, chemical smell, hygienic, concerns about tap water, use as luxury item or status symbol, advertising by the producer, shape of the bottle (small or big),and convenience or readily availability of the water. This study suggests that the producers of bottled water should give importance on the health and hygiene aspects and promotional factors for promoting their sales in Bangladesh.

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