Plastic in every sip: The toxic truth about bottled water
About 70 per cent of the human body is made up of water, which plays a vital role in delivering oxygen to the brain, transporting nutrients, aiding digestion and regulating body temperature. However, the very water we depend on may contain invisible threats —nanoplastics, plastic particles measuring less than 100 nanometres.
Emerging research shows that these plastics have infiltrated our drinking water, raising serious health concerns. Recognising the importance of this resource, the UN declared safe drinking water a fundamental human right in 2010, as part of the Sustainable Development Goals, which aim to ensure universal access by 2030. Yet, as of 2022, around 2.2 billion people lacked access to this basic necessity.
Of the primary drinking water sources, such as municipal water supplies, bottled water and household filtration systems, bottled water is the preferred choice for millions, widely perceived as safer and purer than tap water. However, recent studies reveal that bottled water often contains far more plastic contaminants than tap water, undermining its perceived superiority.
Plastic bottles, primarily made from polyethylene terephthalate (PET), contribute significantly to environmental pollution through their production, transportation and disposal. The discarded bottles persist in the environment for decades, breaking down into microplastics (under 5 mm) and nanoplastics. As a result, plastic pollution has escalated into a global crisis, contaminating oceans, rivers and even the most remote ecosystems. Studies have detected microscopic plastics in marine life, soil and even human blood, raising concerns about their presence in the food chain and potential health impacts.
A 2018 study found that bottled water contained an average of 325 microplastic particles per litre, far exceeding the levels found in tap water. At that time, detection methods were limited to microplastics.
However, in January 2024, scientists from Columbia and Rutgers universities introduced a powerful hyperspectral-stimulated Raman scattering optical imaging platform that is capable of detecting nanoplastics at the single-particle level with high sensitivity and specificity. Published in the Proceedings of the National Academy of Sciences, this study detected nanoplastics in bottled water for the first time, with an average of 2,40,000 detectable plastic particles per litre — about 90 per cent classified as nanoplastics. These numbers are 10 to 100 times higher than those reported in earlier studies that counted only microplastics.
These contaminants originate primarily from bottle materials, caps and filtration processes used in production. Repeated opening and closing of caps and exposure to heat and sunlight exacerbate the plastic particle release.
The health risks of ingesting these plastic particles are concerning. The minuscule size of nanoplastics, invisible to the naked eye, allows them to enter the bloodstream and accumulate in vital organs. Scientists have identified three primary risks: direct toxicity, chemical leachates and microbial contamination. The toxicity of plastic particles can trigger inflammation and cellular damage. Chemical additives such as phthalates and bisphenols, commonly found in plastics, can disrupt hormones, leading to reproductive and metabolic disorders. Additionally, tiny plastics act as carriers for harmful pathogens, increasing infection risks.
Plastic particles have been detected in human blood, lungs, gastrointestinal tract and even placenta. Microplastics can infiltrate critical organs, while nanoplastics pose a greater risk as they can cross the blood-brain barrier, potentially contributing to neurotoxicity and cognitive decline. Prolonged exposure to plastic contaminants may increase oxidative stress, raising the risk of cancer, cardiovascular disorders and metabolic disruptions. Research suggests nanoplastics can also alter gut microbiota, affecting immune responses and overall health. Long-term studies are needed to fully understand their effects.
Given these risks, is bottled water the safer option? In urban areas, tap water is often a more sustainable and cost-effective alternative, undergoing rigorous treatment, including disinfection, filtration and contaminant-testing. While some municipal systems suffer from aging infrastructure and occasional contamination, tap water in many countries is subject to stricter regulations than bottled water.
A 2017 study by Orb Media found that while 83 per cent of global tap water samples contained microplastics, their concentration was significantly lower than in bottled water. The WHO has emphasised the need for improved regulatory frameworks to monitor and mitigate plastic contamination in drinking water.
To improve municipal water quality, governments must invest in modernising treatment plants, repairing pipelines and addressing contamination issues. Public awareness campaigns can rebuild trust in tap water and promote sustainable consumption habits.
On an individual level, switching to reusable water bottles and using home filtration systems can significantly reduce plastic waste and exposure to tiny plastics. Filters used under current regulations generally remove particles larger than one micron, including most bacteria, parasites and some viruses, providing adequate protection against harmful contaminants in many public water sources. High-quality water filters, such as activated carbon or reverse osmosis systems, have been shown to reduce microplastic levels in drinking water. Community initiatives, such as public water fountains and refill stations, also play a vital role.
Once considered a symbol of convenience, bottled water now presents hidden dangers to both human health and the environment. While it remains a vital resource in regions lacking safe tap water, its long-term risks demand urgent attention. A critical first step is to prevent further contamination of groundwater and surface water sources. Addressing water insecurity through improved municipal systems and sustainable practices is essential to ensuring universal access to safe drinking water.
Furthermore, continued scientific research is necessary to uncover the full extent of microplastic exposure and its biological effects, enabling policymakers to implement stronger regulations for public health and environmental sustainability. By tackling these challenges, we can ensure that safe drinking water is accessible to all, protecting both people and the planet.
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