People may be ingesting between 3,000 and 4,000 microparticles of plastic from tap water every year, said a study Wednesday based on samples from 14 countries.
While
the health risks are unknown, the researchers pointed to previous
findings that plastic particles can absorb, and release, potentially
harmful chemicals and bacteria.
For the survey, 159 tap water samples were analysed of which "83 percent were found to contain plastic particles," researchers from the University of Minnesota and the State University of New York wrote in a report entitled: "Invisibles: The plastic inside us".
While
much research has focused on plastic pollution of lakes, rivers, the
ocean, beaches, even the air we breathe, less attention has been paid to
its presence in human consumables, said the team.
This was the first study to look at micro-plastics in drinking water, they added.
Samples
were collected in the first three months of the year in Kampala,
Uganda; New Delhi, India; Jakarta, Indonesia; Beirut, Lebanon; Quito,
Ecuador; several cities in the United States and in seven European
countries.
All were sent to the University of Minnesota, Minneapolis, for lab testing.
By far the majority of particles found were fibres ranging from 0.1 to five millimetres (0.004-0.2 inches) in length.
The range was from zero to 57 particles per litre of water, with an average of 4.34 particles per litre.
"The
highest density of plastic per volume of tap water was found in North
America and the lowest densities were found, collectively, in seven
European countries," wrote the team.
More research needed
Based
on liquid consumption of three litres (6.3 US pints) per day, as
recommended, a man may consume as many as 14 plastic particles daily if
his chosen beverages were tap water or made with tap water, said the
authors.
For women, this would amount to about 10 particles for an intake of 2.2 litres.
"These daily doses add up to an annual total of over 4,000 for men and over 3,000 for women," wrote the team.
"These
plastic particles are in addition to plastics potentially consumed in
other products, such as sea salt, beer and seafood."
A
study in January said a European shellfish consumer may be ingesting up
to 11,000 micro plastics per year from that source alone.
The
researchers used the same plastic containers in which the samples were
collected to test treated water from the lab, to rule out plastic
contamination from the bottle itself.
"The
results of this study serve... as an initial glimpse at the
consequences of human plastic use (and) disposal rather than a
comprehensive assessment of global plastic contamination," the team concluded.
They
called for further tests to gather more data about potential pollution
sources and pathways, as well as the risks to human health.
Micro-plastics
are less than 5 mm long, about the size of a sesame seed. They come in
the form of "micro-beads" used in scrubs and toothpaste, and can also be
created when larger pieces of plastic waste degrade.