What’s lurking in your water? The risks of bacteria and microplastics

[KENNEDY FELTON]

It’s hard to hydrate these days. Not only are you likely swallowing thousands of tiny plastic particles without realizing it, but every sip from your reusable water bottle could also be fueling bacteria that multiply by the millions in just 24 hours.

But what if simple changes could cut down on both? Studies reveal just how much you can reduce your microplastic intake, while another details how often you really need to wash your water bottles.

90,000 particles. That’s how many microplastics you’re likely ingesting from plastic water bottles each year, according to a study published in Genomic Press. But by switching to filtered tap water, researchers say that number significantly drops to just 4,000 particles per year.

You may feel like you’re constantly hearing about microplastics—and how harmful they can be—but they aren’t just in the water you drink. The same study also highlights seafood and alcohol as major dietary sources of microplastics.

It’s not just what we consume, but also what our food is stored in. Many people are ditching plastic Tupperware after recent studies. One 2023 ACS Medical Paper found some plastic food containers can release up to 4.2 million microplastic particles per square centimeter within just three minutes of microwave heating.

Recent studies reveal microplastics contain hormone-disrupting chemicals like BPA, which have been linked to reproductive issues and developmental problems. They can also carry toxic chemicals that get released into your body when ingested, and they may trigger inflammation, which has been linked to chronic diseases like cancer, heart disease, and autoimmune conditions.

Microplastics have been found in human blood, lungs, and even placentas—raising concerns about long-term health impacts that are still being uncovered. Now, a Genomic Press paper suggests that increased levels of micro- and nanoplastics in the brain could be especially concerning, particularly in patients with dementia.

But what about those reusable water bottles and the bacteria inside them?

A BBC article reveals that, from every sip, you deposit bacteria in your bottle. In just one day, that bacteria can multiply by millions. Leaving the water sitting in your bottle for days only encourages even more bacterial growth. A clinical microbiology associate professor in the UK explains that the longer water sits at room temperature, the more bacteria will grow. That’s because bacteria that cause human infections thrive around 98 degrees Fahrenheit but can still multiply at room temperature—around 68 degrees.

On average, reusable bottles see bacteria levels jump from 75,000 per milliliter in the morning to more than 1.2 million within just 24 hours. However, that same professor notes most of these bacteria are harmless, and non-immunocompromised systems are strong enough to fight off many of them. But some bacteria can be disease-causing, which is why proper cleaning is so important.

So, how should we be cleaning these bottles?

The study found that people who used a cleaning brush or dishwasher had the lowest bacteria counts, but bacteria were still present no matter how often or what method was used. The most effective way is running your bottle through a dishwasher sanitation cycle. Hot water over 140 degrees is key since it kills most pathogens.

And it’s not just water—bottles with tea, coffee, or juice were found to be even more contaminated than those with just water. If at any point your water bottle starts harboring a smell, you should get rid of it entirely. Plastic reusable water bottles that are not BPA-free could be the most harmful because the bacteria can bind to the plastic, which could then lead to further health issues mentioned earlier.