The plastic ingestion scourge

Plastics undoubtedly affect our environment – and they are shaping up to be an emerging threat to human health as with every breath and every bite, plastics are entering our bodies – without researchers having a full grasp of the implications.

Micro- and nanoplastic particles permeate the most essential sustenance for human life

Plastic bottles, beads, and wrappings can hardly get into the human body. However, when they start to break down, these large items transform into tiny but scary microplastics, nanoplastics, or even smaller particles that are flooding the air we breathe, the water we drink, and the food we eat.

A new study at the University of Newcastle titled “How much microplastics are we ingesting? Estimation of the mass of microplastics ingested”, commissioned by WWF Singapore, reveals that the consumption of common food and beverages may result in a weekly ingestion of approximately five grams of plastic, depending on consumption habits. In particular, the largest amount of microplastics hit our body through drinking.

The university calculated the average amount of plastic ingested by humans by analysing and synthesising the existing, but limited literature on the topic exists. The results confirm concerns over the large quantity of plastic humans ingest every day.

It also highlights the key ways plastic gets into the body, such as through food and beverages, and indoor and outdoor air. Out of a total of 52 studies that the University of Newcastle included in its calculations, 33 looked at plastic consumption through food and beverages.

Microplastics, defined as plastic particles under 5mm in size, are contaminating the air, food, and water. Primary microplastics are plastics directly released into the environment in the form of small particulates (shower gel micro beads and tyre abrasion, among others) while secondary microplastics are microplastics originating from the degradation of larger particles.

Water is an indispensable resource to human life and drinking water (groundwater, surface water, tap water, and bottled water) is the largest source of plastic ingestion all over the world. Bottled water, people’s choice for healthy, non-contaminated drinking water, is even richer in plastics, containing some 10,000 microplastic particles per litre, twice as much as regular tap water, according to a report by Orb Media.

In Vietnam, bottled-drinks fanatics might be familiar with major brands like Universal Robina Corporation’s C2 green tea, Red Dragon drinks, or THP Group’s Dr. Thanh tea and oolong tea, and Suntory Pepsico’s wide range of drinks, that are packed in plastic and can easily be found in any convenient store or supermarket.

The alarm bell is sounding not only over bottled drinks – tea drinkers who prefer costly, silky plastic teabags might get more than they bargained for in each cupful of liquid refreshment.

A team of researchers from McGill University and the Quebec government announced shocking stats that about 11.6 billion microplastic and 3.1 billion nanoplastic particles can leak into water from a single plastic teabag at brewing temperature, thousands of times higher than the amount reported previously in other foods. The teabags in the study appeared to be from the premium category which consumers turn to with more trust than regular tea bags.

Inhalation is estimated to account for a negligible portion of microplastics entering the human body but this may vary heavily depending on the environment. The study surveyed 16 papers focusing on outdoor and indoor air quality. The results showed that indoors are more heavily plastic polluted than outdoors.

Reacting to the concerning statistics, the WWF said that the production of virgin plastic has increased 200-fold since 1950 and has grown at a rate of 4 per cent a year since 2000. If all predicted plastic production capacity is reached, current production could increase by 40 per cent by 2030.

Threats to human health

Going forward, scientists are working to obtain more precise information on pollution from plastic, how it is distributed, and how much is consumed.

The long-term effects on human health of ingesting large quantities of plastic are not clear but studies are underway. However, scientists suspect that the health hazard may be more substantial than currently understood.

Studies have shown that beyond a certain exposure level, inhalation of plastic fibres seems to produce a mild inflammation of the respiratory tract.

In marine animals, higher concentrations of microplastics in their digestive and respiratory system can lead to an early death. Research studies have demonstrated toxicity in vitro to lung cells, the liver, and brain cells.

Some types of plastics carry chemicals and additives with potential effects on human health. Identified health risks are due to the production process of residues, additives, dyes, and pigments found in plastic, some of which have been shown to have an influence on virility, fertility, and increased occurrence of mutations and cancers.

Airborne microplastics may also carry pollutants from the surrounding environment. In urban environments, they may carry polycyclic aromatic hydrocarbons – molecules found in coal and tar − and metals.

Studies are underway to better understand the health effects of plastic. A key challenge to research is the overwhelming presence of plastic in our daily life, making it very hard to isolate the effect of a specific exposure pathway from others. The World Health Organization is currently undertaking a review of the health impact of microplastics.