Plastic pollution is one of the most pressing environmental issues of our time, affecting not only the ecosystems and wildlife, but also the quality of our food and water. While the presence of microplastics (plastic particles smaller than 5 mm) in drinking water has been widely reported, a new study reveals that bottled water may contain even smaller and more abundant plastic particles: nanoplastics.
Nanoplastics are defined as plastic particles smaller than 1 micrometer (one thousandth of a millimeter), which are invisible to the naked eye and most conventional analytical methods. They can originate from the degradation of larger plastic debris, or from the manufacturing of nanomaterials and products. Due to their small size, nanoplastics can easily penetrate biological membranes and tissues, and potentially cause adverse effects on human health.
The study, published in the journal Proceedings of the National Academy of Sciences, used a novel optical imaging technique to detect and quantify nanoplastics in three popular brands of bottled water. The researchers found that on average, a liter of bottled water contained about 240,000 plastic particles, of which 90% were nanoplastics. This is 10 to 100 times higher than the previous estimates based on larger microplastics.
The researchers also identified the chemical composition of the plastic particles by using Raman spectroscopy, a technique that uses laser light to probe the molecular structure of a material. They found that the plastic particles included polyethylene terephthalate (PET) and polyamide (PA), which are commonly used to make plastic bottles, as well as other types of plastics, such as polystyrene (PS), polypropylene (PP), and polyethylene (PE).
The source of the nanoplastics in bottled water is not clear, but the researchers suggest that they may come from the bottle itself, the cap, the label, or the production process. They also point out that the reverse osmosis membrane filter, which is widely used to purify water, may generate nanoplastics as a by-product of its operation.
The health implications of ingesting nanoplastics are still unknown, but some studies have suggested that they may cause inflammation, oxidative stress, cellular damage, and endocrine disruption in animals and humans. Nanoplastics may also carry other contaminants, such as metals, organic pollutants, and microorganisms, that may pose additional risks.
The researchers call for more studies to assess the exposure and toxicity of nanoplastics in bottled water and other sources, as well as to develop better methods to detect and remove them. They also urge consumers to reduce their use of plastic bottles and opt for reusable or biodegradable alternatives.
The following table summarizes some of the key findings and implications of the study:
| Parameter | Value | Implication |
|---|---|---|
| Average number of plastic particles per liter of bottled water | 240,000 | Bottled water may contain a large amount of nanoplastics that are undetected by conventional methods |
| Average size of plastic particles | 0.6 – 15 micrometers | Nanoplastics may be more harmful than microplastics due to their ability to cross biological barriers and enter cells and organs |
| Types of plastics detected | PET, PA, PS, PP, PE | Nanoplastics may originate from the bottle, the cap, the label, or the production process, and may have different chemical and physical properties |
| Potential health effects of nanoplastics | Inflammation, oxidative stress, cellular damage, endocrine disruption, etc. | Nanoplastics may cause adverse effects on human health, especially in the long term and at high doses |
| Potential solutions | Better detection and removal methods, reduced use of plastic bottles, reusable or biodegradable alternatives | Nanoplastics in bottled water can be prevented or minimized by improving the quality and safety of water sources and packaging |
To learn more about the study and the issue of nanoplastics in bottled water, you can watch this video from CBS News, featuring an interview with Dr. Celine Gounder, a public health expert and medical contributor.
