Are plastic bottles safe in the sun?

By Donna Eastlake

- Last updated on GMT

Are plastic bottles safe in the sun? GettyImages/HowardOates
Are plastic bottles safe in the sun? GettyImages/HowardOates

Related tags Plastic Packaging volatile organic compounds

Scientists raise concerns that plastic bottles release harmful chemicals when exposed to sunlight.

From the environmental impact to the presence of PFAS​, plastic food and beverage containers have come under close consumer scrutiny in recent years. Now, a study from Jinan University in China is again placing plastic packaging under the spotlight, with evidence to suggest that sunlight-exposed plastic water bottles release harmful volatile organic compounds (VOC).

Are plastic water bottles safe after exposure to sunlight?

The study, conducted at the Guangdong Key Laboratory of Environmental Pollution and Health, looked specifically at the potential health hazards associated with volatile organic compounds, emitted from plastic water bottles, when they are exposed to sunlight. The research investigated the types and toxicity of volatile organic compounds released under ultraviolet-A (UVA) and solar irradiation, highlighting the importance of improved storage methods to guarantee the safety of drinking water.

What are volatile organic compounds (VOC)?

Volatile organic compounds (VOC) are organic compounds that have a high vapor pressure at room temperature.

Some VOCs are dangerous to human health and can be harmful to the environment. While they are not acutely toxic, they can impact health, causing eye, nose, and throat irritation, headaches and loss of coordination, nausea, and, more severely, damage to the liver, kidneys, and central nervous system.

Drinking from plastic water bottle - GettyImages-PIKSEL
Approximately 500 billion plastic bottles are used worldwide yearly, but are they safe after sun exposure? GettyImages/PIKSEL

Plastic water bottles are used across the globe and are, by some, considered a safer option when compared to tap water. In fact, a recent survey from business intelligence platform, Statista, found that 25% of respondents did not believe that the tap water in their homes was suitable for drinking.

“Around 500 billion plastic bottles are used worldwide yearly,” says Inemesit Ukpanah of sustainability price comparison site, GreenMatch.

Plastic water bottles are also considered to be convenient, with 46% of respondents saying they buy them because they can drink them on the go.

But should consumers be drinking bottled water outside where the bottles can be exposed to sunlight?

Plastic Water Bottles Cover - GettyImages-monticelllo
The research team analysed the effects of sunlight on a variety of different water bottles. GettyImages/monticelllo

The researchers found evidence that exposure to sunlight can lead plastic bottles to degrade and emit volatile organic compounds, which are potentially damaging to human health.

The scientists analysed the volatile organic compounds released from six types of plastic water bottles exposed to UVA radiation and sunlight. The results, published in the journal, Eco-Environment & Health, showed that all bottles tested, emitted a complex mixture of alkanes, alkenes, alcohols, aldehydes, and acids, with significant variations in volatile organic compounds composition and concentration among the bottles. They noted that highly toxic volatile organic compounds, including carcinogens such as n-hexadecane, were identified.

The team concluded that their finding highlighted serious health risks when consuming liquids from plastic bottles, which had been exposed to sunlight. Furthermore, results indicated that prolonged exposure increased the concentration of volatile organic compounds, leading to a greater cumulative risk.

“Our findings provide compelling evidence that plastic bottles, when exposed to sunlight, can release toxic compounds that pose health risks,” said Dr Huase Ou, lead researcher on the study. “Consumers need to be aware of these risks, especially in environments where bottled water is exposed to sunlight for prolonged periods.”

Though the research was conducted on plastic water bottles alone, there is the potential that all plastic bottles, including bottles containing soft drinks and alcohol, would be subject to the same effects.


Source: Characterizing the photodegradation-induced release of volatile organic compounds from bottled water containers
Published online: 12 April 2024
Authors: Ruijuan Liu, Zhianqi Liao, Jing Zheng, Xinni Wu, Zongyi Tan, Huase Ou 

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