Abstract
A common perception is that bottled water offers the cleanest option for potable water, leading many consumers to prefer bottled water over tap or well-water supplied directly to their residence. Within bottled waters, there is also a price gradient that carries a perception of a positive relationship between price and purity. However, microplastics are an emerging pollutant that often aren’t considered when choosing a potable water source. Throughout the pumping, bottling, transportation, storage, and opening processes, there are many potential avenues for microplastic contamination in bottled water. To evaluate microplastic concentrations in bottled water and across a price gradient, we purchased 10 – 1L bottles each of 10 separate brands of bottled water at a grocery store. The water within each bottle was vacuum filtered through a 0.45um filter, stored in a closed petri dish, and counted for microplastics. Microplastics were categorized as either fibers, fragments, microbeads, or films. A range of 2 to 307 pieces per liter, with an average of 29 pieces per liter. Fragments dominated all of the samples with about 85% of all plastics being fragments. Contrary to assumptions, results showed that both the most expensive brand of bottled water had the most microplastics (mean of 69 pieces per liter). The next highest concentration of microplastics was found in the least expensive brand of bottled water (49 pieces per liter). Overall, there were no trends between price and number of microplastics. Future studies on this topic exploring the influence of filtration, bottling, and transporting on microplastic concentrations in drinking water.
