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

Abstract

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 the 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 the 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 versus bottled water. Escherichia coli concentrations were >0 CFU/100 mL in some unsealed bottled water samples but not in 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.

Is Bottled Water More Reliable Than Tap Water in Mexico? A Case Study of Household Mental Health Conditions in Two States

“…Anguera-Torrell and Arrieta-Valle [15] noted that society bears monetary costs associated with plastic bottle generation, transportation, and disposal. In addition, the price of C/B is critically greater than that of tap water, which exacerbates economic disparities, especially in low-income communities [16]. Moreover, there are some health risks associated with using bottled water.…”

“…Generating, transporting, and disposing of plastic bottles also impose financial costs on society [15]. Moreover, bottled water costs significantly more than tap water, ranging from 100 to 1000 times higher, intensifying economic inequalities, particularly in underprivileged populations [16]. Thus, the wide usage of C/B among Mexicans is a significant issue requiring further attention.…”