Measuring microplastics in humans is challenging but researchers already have preliminary figures, writes Thava Palanisami of the University of Newcastle in Australia. Meanwhile, as more Indonesians eat fish as part of their diet, Veryl Hasan of Airlangga University considers the risks.
Cocktail of contaminants: Microplastics could pose a significant threat to human health in the long run because substances in them have been linked to illnesses and disease (Credit: David Pereiras / Shutterstock.com)
Plastic waste is increasingly engulfing everything on the planet from ecosystems to people but we do not have adequate knowledge of its full ill effects. We do not know exactly how many microplastics humans are ingesting daily and what are the possible consequences. To date, only a few studies have been launched to address these basic questions of human health. A recent study by researchers in Australia and Singapore estimates that globally on average, humans may take in 0.1-5 g of microplastics weekly through various pathways. Commonly, these are through food and drink, inhalation and even dermally (through our skin). These minute particles (less than 5mm) then travel through the human digestive, respiratory and circulatory systems.
Microplastics are often referred to as a “cocktail of contaminants” due to their presence in chemical additives, heavy metals, pharmaceuticals, pesticides and other organic pollutants in the environment. Microplastics could pose a significant risk to human health in the long run as the contaminants within them have been linked to several human illnesses and diseases including endocrine disorders, cardiovascular and reproductive problems plus obesity, diabetes and cancer.
It is therefore pressing that researchers determine the quantity of microplastics being taken in by the human system and its potential impacts. A definitive global average rate of microplastic ingestion (GARMI) is needed to assist in human health risk assessments and to formulate effective management and policy options.
The preliminary study shows that microplastic particles are potentially ingested through the consumption of water, shellfish, fish, salt, beer, honey and sugar. Globally, humans potentially ingest between 11,845 to 193,200 microplastics per person per year ranging between 7.7 g and 287 g per person per year with the largest source being drinking water (both tap water and bottled water).
This estimation of the average rate of microplastic ingestion can form the basis of a human health risk evaluation. Apart from food and drink, studies that probed the inhalation of microplastics via aerosols and household dust showed a high risk to humans with lungs potentially exposed to an additional 26-130 microplastic particles every day. Generally, higher counts of microplastics were reported in bottled water and this is likely due to its packaging and processing. Raw or untreated water is not included in studies as it is more challenging to identify and quantify the finer plastic particles. Curiously, the amount of microplastics found in raw water samples to date was the same as those obtained for bottled water.
Identifying and quantifying fine microplastics (less than 1mm) is a key challenge facing researchers and the field is still new. Currently, Raman spectroscopy and Fourier-transform infrared spectroscopy (FTIR) are used but they are not perfect. For instance, the intensity of the laser in these instruments could damage the microplastics being studied and measured.
Contaminants in microplastics have been linked to serious health outcomes. Interestingly, an experimental study revealed that the size of a microplastic particle influenced its ingestion rate. This more than its shape which suggests research focusing more on size is needed.
Who is at more risk of consuming microplastics?
An individual's vulnerability to ingestion of microplastics will influence their level of exposure. For example, those with significant consumption of shellfish and bottled water and with a high-calorie intake will be more likely to have increased exposure compared to those who consume less.
Individuals who often consume plastic-packaged food and drink, meanwhile, will have higher exposure as microplastics in consumables is a direct result of plastic packaging.
It is also possible that people from regions with low dependence on plastic products, better waste management facilities, quality water sources and good policies with respect to food health and safety will be at less risk to microplastic exposure compared to those from places still developing in these areas.
Further research is necessary to confirm this. Nonetheless, there is enough evidence to indicate these variables influence people's exposure and the global average rate of microplastic ingestion.
There are a number of hurdles for scientists when measuring the average rate of microplastic ingestion due to insufficient data, differences in identification techniques, analytical challenges, disparate reporting metrics and uncertainties as well as varied experimental conditions.
The uncertainty level goes up with every assumption and extrapolation – this can only be reduced with more research. Recommendations for future directions include standardizing analytical methods and parameters for microplastics collected during studies (e.g. size, shape, polymer, number of particles, mass of particles).
To determine the negative health impacts, studies on the influence of variables on the global average rate of microplastic ingestion must also be done. More detailed data from other food groups consumed daily – oils, meat, pasta, bread, corn, wheat, milk, rice, wheat, corn – needs to be collated. Also to be further probed is the toxicity of microplastics ingested in terms of size, mass, polymer and shape and determining the extent microplastics travel from cooking and eating utensils (especially by children) and food packaging into food.
The worldwide presence and pervasiveness of microplastics are accepted facts, however, the amounts of microplastics humans ingest are yet to be fully defined. Still, early data indicates that a cautionary approach is embraced now to avoid a future crisis.
More Indonesians are eating fish as part of their regular diet but microplastics do make it risky. There are ways to mitigate that risk.
Susi Pudjiastuti, Minister of Maritime Affairs and Fisheries of Indonesia (2014-2019) once made a popular joke about Indonesians who did not eat fish: "I will go after you who don't eat fish, you will be sunk like those vessels.” The vessels she referred to were foreign fishing trawlers. The word "sink" became a popular meme on social media and underscored how important fish is to Indonesians.
Fish is a crucial source of protein for Indonesians. Indonesia is the second largest fisheries producer after China and the industry plays a huge role in the country’s economy. The sector is only expected to grow, especially in aquaculture, with traditional catches decreasing due to overfishing. Coupled with a global consumption trend that is starting to switch from red meat to fish, fishery products are becoming easier to obtain and more affordable.
But there is a risk. Eating fish while they are also eating plastic can be dangerous. Because water quality continues to be degraded, the quality and quantity of fish caught and cultivated also decreases, mainly due to inorganic waste that is difficult to decompose such as microplastics. It is estimated that by 2050 there will be more plastic waste than fish in the sea.
Indonesia is the second largest producer of plastic waste in the world after China. Plastic use in Indonesia continues to increase, spurred by the development of the packaged food industry. Although the public is not generally concerned about the adverse effects of plastic waste on the environment and health, plastic pollution is becoming a big problem, with cases of illegal entry of plastic waste from some developed countries worsening the problem.
The handling of plastic waste in Indonesia has not been well integrated, especially in densely populated rural areas where there are no garbage disposal facilities. This means plastic waste is either burned or thrown into waterways.
Burning plastic produces toxic air pollution and has been banned except under exceptional circumstances. Pollution from burnt plastics also ends up in the soil and water due to the leaching of the remaining material. The easier option is for people to throw unwanted plastics into waterways. The sight of people throwing plastic waste over bridges has become common in Indonesia.
One of the risks of all this plastic floating around waterways is that it can contribute to flooding. It also breaks down into microform (less than 5 mm). It is these microplastics that put aquatic life – and the humans who rely on it – at risk.
Fish are opportunistic feeders and tend to eat objects in the water that resemble their food. In general, fish cannot distinguish between natural food and microplastics because they can be the same shape and color. Microplastics then settle in the digestive tract of fish. This can lead to unhealthier and reduced fish populations due to malnutrition. For humans, the microplastics in fish can still be avoided by cleaning the fish’s digestive tract before consuming them. This is considered the easiest way to prevent microplastics from being ingested.
There is still the problem of smaller fish, such as anchovies, which are consumed whole. Microplastics are destined to enter humans and end up in our digestive tract. An accumulation of these foreign materials can have dire consequences for human health, such as digestive disorders and even poisoning.
It is not only fish which carry risks. Drinking water can contain nanoplastics (less than 100 nm) which are barely visible to the naked eye. Most Indonesians rely on drinking water from the nation’s rivers which have been polluted by plastic waste for years. Microplastics are found in almost all rivers in Indonesia and have ended up in processed foods, packaged beverages, and even breast milk.
One environmental NGO found microplastics contamination in 68 rivers from 24 provinces in Indonesia. There are between 6.36 to 4.17 particles per liter. From thousands of respondents to one survey, 90 percent agreed that Indonesian rivers are polluted but they are ready to voluntarily help clean it up.
The solution to the microplastic problem lies with three sections of society:
There needs to be community participation in dividing waste according to criteria such as organic and inorganic waste, especially plastic. This division will make it easier to recycle waste. Organic waste can be processed into compost, while plastic waste is converted into plastic pellets which are ready for reuse.
The industry has so far paid little attention to the plastic waste generated from their products, because they think that products that have been released and consumed by the public are the responsibility of the community. The plastics industry needs to be encouraged to provide waste processing facilities and systems according to the product criteria produced.
The government is responsible for providing sustainable and integrated waste management facilities and systems from urban to rural areas. It also should agree with industry on building facilities and systems to process plastic waste.
This article is published under Creative Commons with 360info.
Alberghini, Leonardo; Truant, Alessandro; Santonicola, Serena; Colavita, Giampaolo; and Giaccone, Valerio. (December 31, 2022) “Microplastics in Fish and Fishery Products and Risks for Human Health: A Review”, International Journal of Environmental Research and Public Health, MDPI, Basel, Switzerland.
Lusher, Amy; Hollman, Peter; and Mendoza-Hill, Jeremy. (2017) “Microplastics in fisheries and aquaculture: Status of knowledge on their occurrence and implications for aquatic organisms and food safety”, FAO Fisheries and Aquaculture Technical Paper, no. 615, Food and Agriculture Organization (FAO), Rome, Italy.
Wong, Pui Yi. (August 20, 2020) “Unhealthy Air and Plastic Waste: The Nexus of Pollution, Public Health and Corruption”, AsiaGlobal Online, Asia Global Institute, The University of Hong Kong.
University of Newcastle