The Dark Effects of the Sun on Plastic Drinking Bottles

Stop drinking plastic water!

This may be hard to swallow, but the drinking bottle that you are dutifully carrying around with you all day to stay properly hydrated may be delivering more than water into your body.

The most commonly used plastic water bottle is made of polyethylene terephthalate, or PET, which is indicated on the bottle with a stamp of the number “1" surrounded by arrows. This plastic is considered safe to use for water. But is it?

While some chemical residues from the production process contaminate all plastic containers and can be released into the contained food or drink, PET plastic water bottles are relatively low in these chemical residues, making them relatively safe to use for water, if the bottle is used as intended.

Most people don’t know the environmental conditions for which their plastic bottle was made. Actually, these bottles are not intended to be exposed to sunlight, or be stored in a hot car.

UV radiation from sunlight has the ability to break chemical bonds in plastics, including PET, and this causes the plastic to quickly decompose. This also happens when people keep their water bottle in their car, or beside them at the beach.

According to an article in Recycle Magazine, “The data clearly shows that exposure to ultraviolet radiation was very damaging to the PET material…Exposure to UV radiation, whether it is from outside storage or possibly even exposure to fluorescent lighting in retail stores, should be considered as another contributor to PET quality degradation.”  In other words, sunlight and heat breakdown the plastic, producing a slew of chemicals.

What’s wrong with the chemicals from plastics breaking down? According to the Endocrine Society, “Plastics contain and leach hazardous chemicals, including endocrine-disrupting chemicals (EDCs) that threaten human health…EDCs are chemicals that disturb the body’s hormone systems and can cause cancer, diabetes, reproductive disorders, and neurological impairments of developing fetuses and children. The report describes a wealth of evidence supporting direct cause-and-effect links between the toxic chemical additives in plastics and specific health impacts to the endocrine system.”

Note that these PET water bottles are not meant for use in the sunlight or heat. Having a plastic bottle of water with you at the beach sitting in the sunshine, or sitting in your hot car, are considered a misuse of the bottle, and essentially voids health assurances by releasing more chemicals than expected from test without heat or sunshine.

One chemical we haven’t discussed is antimony, a heavy metal that causes cancer. According to the Ecology Center in their PET plastic report 2022, “Our partners at Defend Our Health tested 20 popular beverages packaged in plastic bottles and found antimony, a cancer-causing plastic chemical, in every bottle. 40% of beverages tested, including Pepsico and Coca-Cola brands, had antimony levels higher than California’s public health goal for drinking water. Antimony, known to be toxic to the liver and heart, is used to speed up the final reaction in the process of making PET (#1) plastic. This same polymer is the common "polyester" used in apparel and other textiles. This means the problem doesn’t end with plastic bottles. Antimony is also found in food packaging and other packaging made from PET, as well as clothing, stuffed animals, and other polyester items.”

Chemical contaminants from PET water bottles can act as a hormone disruptor, a carcinogen, and an irritant to the skin, kidneys, nervous system, intestines, and liver. If you can smell it, it goes from your nose to your lungs into your bloodstream. If you can taste it, you are going to swallow and absorb it.

You would expect that there would be lots of studies on plastic chemical toxicity in humans, given the vast daily exposure we all have to food and drink contaminated with plastic residue and breakdown products. On the other hand, 390.7 million metric tons of plastic was produced in 2021, and the amount is growing. That’s a lot of economic incentive to keep things going plastic. Why bother with the science of plastic-caused disease when we all love plastic so much?

According to the Cleveland Clinic, “The science of plastics and health is a little fuzzy. Many ingredients in plastic haven’t been thoroughly tested in people. Much of what we know comes from studies in animals. We don’t know exactly how all these compounds affect human health. But there are hints that compounds in plastics may be linked to problems.”

If you want to take the hint and avoid plastic poisons in your water, here are some suggestions:

1. Use alternatives to plastics, especially glass, whenever possible.

2. If you use plastic PET bottles, keep them out of the sunlight. If outdoors, keep the plastic bottle covered and cool.

3. Don’t keep bottled water sitting in the hot car.

4. Keep in mind that you don’t know the history of that plastic bottle, and whether anyone, including the store where you purchased it, kept the plastic water bottles in the sun and heat. You might want to first try a bottle before buying a case to make sure it doesn’t smell or taste bad.

5. If the contents on any bottle look, smell, or taste bad, do not consume and discard the bottle.

6. Be aware than flavored drinks may mask the plastic smell and taste.

7. Store PET water bottles in a cool, dark place.

8. If you are storing water for emergencies in plastic containers, regularly check the water for smell and taste, which can indicate a need to replace the water and the container.

9. Keep all plastic containers of food and drink out of the sun and heat and away from florescent lighting, which also emits UV.

The convenience of using PET for water bottles will keep it popular with industry and the public over the foreseeable future, despite the increasing evidence showing health risks from plastics exposed to UV. Hopefully, the plastics industry will continue to improve on water bottle chemistry, so all you drink in a plastic bottle of water is water.