Inside the making of water bottles

Patna: Water bottles are generally manufactured using different types of plastic, each possessing specific characteristics. PET (polyethylene terephthalate) is the most commonly used material for single-use water bottles.

It is lightweight and recyclable but may degrade with repeated use. HDPE (high-density polyethylene) is typically used in thicker, reusable bottles because it is resistant to impact and less prone to chemical leaching. There are also BPA-free plastics, such as Tritan, which are marketed as safer alternatives for reusable bottles as they are heat-resistant and designed for multiple uses.Indian Science Congress Association’s general secretary and chemical scientist Ranjit Kumar Verma said while polythenes do not decay easily and normally do not leach into water, PET bottles are comparatively safer only if they are not made from recycled plastic and remain free from endocrine-disrupting phthalates.

“Though polythenes do not decay easily and are normally not leached into water, the PET is still much safer, if not made up of recycled plastic and is free from the endocrine disrupting phthalates. Recycled bottles of either material are more dangerous and need to be banned for making such bottles,” he said.Patna University geology department teacher Bhavuk Sharma, who has been researching different aspects of water quality, said nano-plastics can travel through tissues of the digestive tract or lungs and enter the bloodstream, distributing harmful chemicals within the human body.

Water stored in local plastic bottles may also contain Bisphenol A (BPA), a chemical that scientists say can pose serious risks to human health. Studies indicate that BPA can disrupt the human immune system by affecting immune cell functioning over time. Researchers have also linked BPA exposure to conditions such as diabetes, obesity, fertility problems, behavioural issues and early puberty in girls.Sharma pointed out that the risks become more pronounced in countries like India where summer temperatures remain extremely high.

Plastic bottles used by small packaging units are often exposed to heat during storage or transportation.“Heat accelerates the breakdown of plastic and increases the likelihood of chemical leaching. Moreover, single-use PET bottles are not designed for repeated use. Every reuse increases the risk of physical degradation and microbial contamination,” he said.Apart from potential health concerns, the rapid growth of small bottling units also raises environmental challenges.

Former head of Patna Science College environmental science department Shardendu said plastic bottle usage has grown sharply in recent years.In India alone, more than 14 billion plastic bottles are used annually. A large proportion of these are not recycled and eventually end up in landfills, oceans or incinerators.“Plastic takes hundreds of years to decompose, and in the meantime, it pollutes water bodies, harms marine life, and contributes to the global microplastic crisis. The environmental footprint of manufacturing, transporting, and disposing of plastic bottles is immense, making them an unsustainable option,” he added.