The discovery that most bottled water is contaminated with tiny fragments of plastic has stirred up a mild panic. But do these microplastics actually pose a risk?
According to a study commissioned by , a global consortium of journalists, samples from 93 per cent of 259 bottles contained microplastic particles 鈥� an average of 10 particles wider than 100 micrometres, or roughly the width of a human hair, per litre. The bottles were purchased from countries in five different continents, although not in Europe.
, who carried out the work, found that 54 per cent of these particles were polypropylene, the plastic from which bottle caps are fabricated, suggesting that the caps may have been the source of the particles. Four per cent were industrial lubricants, suggesting that contamination occurred in the factory.
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Mason also found smaller particles 鈥� an average of 325 per litre, although some samples contained up to 10,000 per litre. These were too small to be verified as microplastics, but it seems likely they are, says Mason. These accounted for 95 per cent of all particles found, ranging from 6.5 to 100 micrometres in size.
Minimal hazard
Does it matter if we swallow this stuff? We don鈥檛 really know, but there鈥檚 no need to panic. 鈥淭here鈥檚 no clear evidence about human health risks,鈥� says of the at the University of Plymouth, UK.
Thompson says that if there is a risk, it depends on the quantities we are exposed to. The likelihood is that the amounts in bottled water are minimal compared with other sources, such as airborne dust particles and textile fibres, and possible food sources such as shellfish and crustaceans, which absorb the particles from the sea. 鈥淚鈥檓 not convinced about how significant this bottled water route of exposure is,鈥� he says.
A estimated that hazards to seafood consumers are probably minimal, but deserve deeper investigation. It cited various research in rodents and dogs showing that microplastics larger than 150 micrometres defy absorption, and get excreted in faeces. In all, more than 90 per cent of ingested micro and nanoplastics end up passing through consumers in this way, says the FAO.
Particles smaller than 20 micrometres across did seem to have more potential to cross into blood and accumulate in organs, but whether this is harmful is unknown. Only at huge doses utterly unrealistic in humans 鈥� millions of particles a day 鈥� were there even remote signs of concern in test animals, such as liver inflammation and immunosuppression. 鈥淪uch effects have so far not been reported in humans,鈥� says the FAO report.
Turn to the tap
The risk from fish is tiny, says the FAO, because microplastics are probably only found in their guts, which are removed before we consume them, and exposure would be minimal from seafood eaten whole, like shellfish.
Thompson doubts there is any reason to panic over the bottled water findings, also noting that the study hasn鈥檛 been peer reviewed. 鈥淚鈥檓 not saying it鈥檚 not reliable, but it鈥檚 not gone through the normal processes that would ensure all the necessary details are there,鈥� he says.
The most important thing, says Thompson, is that a huge amount of bottled water consumption in Western nations is unnecessary because tap water is high-quality and easily available. So next time you take a swig, don鈥檛 worry about the minuscule plastic in your water 鈥� instead, fret about the environmental impact of producing and transporting something you really don鈥檛 need. 鈥淭hat, to me, would be a much bigger concern,鈥� he says.
