Risk perceptions of drinking bottled vs. tap water in a low-income community on the US-Mexico Border.

BACKGROUND: Previous studies have shown that low-income Latinos generally drink bottled water over tap water and might be at increased risks for cavities from unfluoridated bottled water. In order to better design interventions, it is important to understand the risk perceptions of this unique high-risk yet historically marginalized group. METHODS: We interviewed low-income Latino households (n = 90) from Nogales, Arizona who primarily drink bottled water and asked them to evaluate potential health risks of drinking tap water compared to 16 other voluntary activities. Unpaired t-tests were used to determine if statistically significant (α = 0.05) differences occurred in perceived risk by drinking-water source and differences among demographic groups in their level of (dis)agreement with statements regarding tap or bottled water safety. To assess significant differences (α = 0.05) in perceived risks and voluntariness to engage in a number of activities, including drinking local tap water and drinking water in different geographic regions, a one-way analysis of variance (ANOVA) followed by Scheffe's post-hoc test (a conservative post-hoc test) with adjustment for the number of pairwise comparisons was used. RESULTS: Participants viewed bottled water to be significantly safer to consume than tap water (p < 0.001). On a Likert scale from 1 (low risk) to 5 (high risk), "drinking tap water in Nogales, Arizona" received an average score of 4.7, which was significantly higher than the average perceived risk of drinking San Francisco, California tap water (µ = 3.4, p < 0.001), and as risky as drinking and driving (µ = 4.8, p = 1.00) and drinking Nogales, Sonora, Mexico tap water (µ = 4.8, p = 1.00). Ninety-eight percent of participants feared that drinking local tap water could result in illness, 79% did not drink their water because of fear of microbial and chemical contamination and 73% would drink their water if they knew it was safe regardless of taste. CONCLUSIONS: These results suggest that fear of illness from tap-water consumption is an important contributing factor to increased bottled water use. Future efforts should focus on the development of educational and outreach efforts to assess the safety and risks associated with tap-water consumption.

Measured and Modeled Comparisons of Chemical and Microbial Contaminants in Tap and Bottled Water in a US-Mexico Border Community.

Tap water quality concerns and advertisements often drive increased bottled water consumption, especially in communities with historical tap water quality problems (e.g., Nogales, Arizona). The study objective was to assess contamination of municipal tap and bottled water in Nogales, Arizona. Bottled (sealed, open/partially consumed bottles, and reusable containers for vended water) and tap water samples were collected from 30 homes and analyzed for chemical and microbial contaminants. Fisher exact tests and Wilcoxon rank sum tests were used to compare proportions of positive samples and contaminant concentrations between tap and bottled water samples. While none of the chemical contaminants were above MCLs, there were statistically significantly greater concentrations and proportions of positive samples for some contaminants, including arsenic, in tap vs. bottled water. E. coli concentrations were >0 CFU/100mL in some unsealed bottled water samples but not for sealed bottles. This study demonstrates that 1) the measured concentrations in tap and bottled water likely pose low risks, as they are below the MCLs, 2) more education in this community on hygiene maintenance of refillable or opened bottled water containers is needed, and 3) using tap water over bottled water is advantageous due to likely lower E. coli risk and lower cost.

Comparison of Fluoride Levels in Tap and Bottled Water and Reported Use of Fluoride Supplementation in a United States-Mexico Border Community.

BACKGROUND: Compared to the general United States (U.S.) population, Arizona counties along the U.S.-Mexico border have a higher prevalence of dental caries, which can be reduced with adequate fluoride exposure. Because of concern regarding local tap water quality, fluoride-free bottled water consumption is common in this region, raising concern that families are not receiving adequate fluoride to promote dental health. OBJECTIVE: To evaluate the levels of fluoride in tap and bottled water as well as the use of fluoride supplements in an Arizona border community. METHODS: Low-income Latino households (n = 90) who report use of bottled water as their primary source of water intake were recruited. Participants completed a questionnaire about their and their children's dental histories and use of fluoride supplements. Water samples (bottled and tap) were collected from a subset of households (n = 30) for analysis of fluoride. RESULTS: Fluoride detection levels were significantly greater (p = 0.02, Fisher's exact test) in tap water (average = 0.49 mg/dL) than in bottled water, yet, the majority (22/30) were below the range for optimal dental health (0.7-1.2 mg/L). Concentration of fluoride in the majority (29/30) of bottled water samples was below the quantitative detection limit of 0.4 mg/L. Children were significantly less likely to have dental caries if they received fluoride varnishing treatments (p = 0.01, Fisher's exact test), lived in households that reported using fluoridated mouthwash (p < 0.001, Fisher's exact test), their parents received fluoride education (p = 0.01, Fisher's exact test), and their parents reported visiting a dentist yearly (p < 0.001, Fisher's exact test). Furthermore, none of the participants reported receiving recommendations from health-care providers about fluoride supplementation or variance in content by the type of water consumed. CONCLUSION: Although fluoride was significantly more likely to be detected in tap than bottled water, neither water source in this border community is likely to provide enough fluoride for optimal dental health. Low-income children in this region may benefit from regular access to fluoride varnishing treatments and/or use of fluoridated mouthwash, interventions that could be tested in future well-designed trials.