Wed, Jul 17, 2019 page8

• Table salt with a pinch of plastic

  • By Bruno Walther
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  Would you like your table salt served with plastic or without plastic? While the obvious answer would be without plastic, you actually do not have a choice anymore.

  Almost all table salts are nowadays contaminated with microplastic particles. This is the result of our most recent research published on Friday last week in Scientific Reports.

  I had reported on the pollution of Taiwan’s coastline with macroplastic and microplastic debris in my previous op-ed (“State must act on plastics problem,” June 4, page 8).

  Here I want to report on what we know so far about the plastic pollution of our foods and drinks.

  In our newest scientific study, we examined 11 table salts that are among the most commonly consumed brands in Taiwan, and we found about 10 microplastic particles per kilogram of salt. Since Taiwanese consume about 3.6kg of salt per year, each person thus consumes about 36 microplastic particles on average.

  Now it should be said that such particles are rather small. The particles that we detected ranged from 1.5mm to 0.1mm, so just about visible to the naked eye to only visible under a microscope.

  We then reviewed all the other scientific studies published worldwide and the resulting averages were considerably higher.

  The best available evidence tells us that, from salt alone, each person ingests several hundred microplastic particles per year. We also know from research that many other foods and drinks are contaminated, such as beer, drinking water, honey, sugar and especially seafood. Since seafood is very popular among many Taiwanese, their consumption of microplastic particles is likely considerably higher.

  For example, the Environmental Protection Administration found from hundreds to thousands of microplastic particles per kilogram of seafood in their study (“Microplastics found in seafood, water: survey,” Sept. 26, 2018, page 3).

  Another study found microplastics in the digestive tracts of most fish (“Most fish contain microplastic: study,” May 14, page 4).

  Consequently, the question on most people’s minds is probably: Is consuming all that microplastic bad for our health or not? The short answer is: We simply do not know.

  Here is the slightly longer and more complicated answer: This problem has only been seriously researched for about a decade, so there are few definitive studies on the health impacts on humans, and more questions than answers.

  Three possible health impacts have been postulated: The ingestion of microplastics could lead to possible internal injury; the contamination of air, food and water with unhealthy substances leached from plastics adds to our overall exposure levels; and microplastics could serve as pathogen vectors.

  Even less is known about the possible impacts of nanoplastics, which are smaller than 1 micrometer (or 50 times smaller than a human hair) and could therefore enter the blood stream and even the brain and internal organs, such as the liver, spleen and reproductive organs.

  Whether these possible effects translate into actual significant health risks is still largely unknown. One report concluded that the presence of microplastics in seafood and other foods probably has a small effect on people’s overall exposure, given all the other contaminants, such as pesticides, heavy metals and particulate matter, to which humans are exposed on a daily basis.

  However, since humans are exposed to an ever-increasing multitude of unhealthy or toxic substances through the air we breathe, the substances that touch our skin, and the foods and drinks we consume, adding another potential pollutant to this list is likely not a good idea. Even more so because we simply do not understand the combinatorial and synergistic effects of all these different pollutants acting together in our bodies (“Beef protest: Overlooking a larger risk to health,” Nov. 22, 2009, page 8).

  I always explain synergisms to my students in this way: Drinking alcohol is bad for you, smoking is bad for you and taking drugs is bad for you, but doing all three is not just three times as bad for you, but much worse, because of the synergistic effects — in other words, one plus one plus one equals five, six or even more.

  Therefore, adding another pollutant to the cocktail of pollutants to which we are already exposed is probably not a good thing.

  We need more research into exposure levels to microplastics and nanoplastics, and their environmental and health effects, but also solutions such as biodegradable plastics (“‘Biodegradable’ plastic still intact after sea, soil burial,” May 1, page 6), substitutes for plastic products (“Start-up begins production of drinking straws made of rice hulls and tea leaves,” July 12, page 4), ways to remove plastic pollution (“Cleaning up ‘plastic soup,’” July 15, 2014, page 12) and how to inspire people to reduce plastic use (“Nation engulfed by plastic tsunami,” Jan. 9, 2015, page 8).

  Finally, what is astonishing is that, instead of encouragement and support, I actually encountered opposition and ridicule for this research at my previous university. And while I secured one year of funding from the Ministry of Science and Technology for research on plastic pollution, for which I am very grateful, a further year of funding was rejected.

  I guess there is still a long way to go until research into plastic pollution is taken serious by parts of the “scientific establishment.”

  Bruno Walther is a professor of biology at National Sun Yat-sen University’s Biological Sciences Department.
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