BOTTLED-WATER CONTAMINANT-MIXTURE EXPOSURES AND POTENTIAL FOR HUMAN EFFECTS

Bottled water consumption in the United States and globally has increased amid heightened concern about environmental contaminant exposures and health risks in drinking water supplies, despite a paucity of directly comparable, environmentally-relevant contaminant exposure data for bottled water. This study provides insight into exposures and cumulative risks to human health from inorganic/organic/microbial contaminants in bottled water. Bottled water from 30 total domestic United States (23) and imported (7) sources, including purified tapwater (7) and spring water (23), were analyzed for 3 field parameters, 53 inorganics, 465 organics, 14 microbial metrics, and in vitro estrogen receptor bioactivity. Health‑benchmark‑weighted cumulative hazard indices and ratios of organic contaminant in vitro exposure-activity cutoffs were assessed for detected regulated and unregulated inorganic and organic contaminants. No enforceable chemical quality standards were exceeded, but several inorganic and organic contaminants with maximum contaminant level goal(s) (MCLG) of zero (no known safe level of exposure to vulnerable sub-populations) were detected. Precautionary health‑based screening levels were exceeded frequently. The results indicate that simultaneous exposures to multiple drinking-water contaminants of potential human-health concern are common in bottled water. Improved understandings of human exposures based on more environmentally realistic and directly comparable point-of-use exposure characterizations, like this bottled water study, are essential to public health because drinking-water is a biological necessity and, consequently, a high-vulnerability vector for human contaminant exposures.