How plastics are turning your food into slow poison

15 days ago

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For years now, the world's oceans and other water bodies have garnered a lot of media attention.

But emerging research shows that plastic pollution poses a bigger threat to plants and animals – including humans – who are based on land. This is because very little of the plastic discarded every day is properly disposed of.

As such, much of it, thanks to some of our irresponsible disposal habits, such as throwing of rubbish out of our car windows, ends up in our gardens, where experts say it is contaminating our food.

The law prohibits plastic carrier bags under 30 microns

Chemicals found in plastics have been linked to a range of health problems, including cancer, heart disease and poor fetal development. High levels of ingested microplastics may also cause cell damage, which could lead to inflammation and allergic reactions, according to a 2022 report published in the Journal of Hazardous Material.

Studies show that chemicals added during the production of plastics can disrupt the endocrine system and the hormones that regulate our growth and development.

How plastics get into our food

When left on land for a long time, the plastics are known to leach (leak) toxic chemicals into the soils, thereby contaminating water bodies and plants.

According to Dr Ambrose James Agona, a plant biologist, plastics are particularly harmful because they cannot be recycled into the soil.

Plastic pollution has led to slow fish growth and death of marine animals

"They are made of polymers, which cannot be degraded by any bacteria or fungus. Once it is in the soil, it is a very big contaminant," he said.

In water, he said findings from a research conducted by the National Fisheries Resources Research Institute discovered microfilms (tiny plastics) of the plastics in the fish population in water bodies in Uganda.

This is causing slow fish growth and deaths of marine animals, he said. But it is not only the fish that were found to be suffering due to ingesting the microfilms.

"When you eat the (infested) fish, it can adversely affect your body because human intestines, like the fish's, cannot digest plastics.

"So technically, it is multiple disasters we are looking at," said Agona, who is also the former executive director of the National Agriculture Research Organisation (NARO).

His revelation is consistent with a 2020 study in Italy on the potential for plastics to enter the food chain. The study, titled "Micro and nanoplastics in edible fruit and vegetables: The first diet risks assessment for the general population", found microplastics in a number of foods, including fruits and vegetables sold by supermarkets in Sicily, Italy.

Apples were the most contaminated fruit, and carrots and had the highest levels of microplastics among the sampled vegetables.

The study indicated that crops absorb nanoplastic particles — minuscule fragments measuring between 1-100nm in size (about 1,000 to 100 times smaller than a human blood cell) from the surrounding water and soil through tiny cracks in their roots.

"For leafy vegetables, such as lettuces and cabbage, the concentrations of plastic would likely then be relatively low, but for root vegetables, such as carrots, radishes and turnips, the risk of consuming microplastics would be greater," the study warned.

Cells damage

In its recent report, titled "How microplastics are infiltrating the food you eat?", BBC revealed that high levels of ingested microplastics may also cause cell damage, which could lead to inflammation and allergic reactions.

The report, which was a result of an analysis by researchers at the University of Hull in the UK, reviewed 17 previous studies which looked at the toxicological impact of microplastics on human cells.

The analysis compared the amount of microplastics that caused damage to cells in laboratory tests with the levels ingested by people through drinking water, seafood and salt.

It found that the amounts being ingested approached those that could trigger cell death, but could also cause immune responses, including allergic reactions, damage to cell walls and oxidative stress.

"Our research shows that we are ingesting microplastics at the levels consistent with harmful effects on cells, which are in many cases the initiating event for health effects," the report, quoting Evangelos Danopoulos, the lead author of the study and a researcher at Hull York Medical School, said.

"We know that microplastics can cross the barriers of cells and also break them. We know they can also cause oxidative stress on cells, which is the start of tissue damage."

Interference with rooting aspects

Agona noted that plastics also interfere with the rooting aspects of plants. This affects the nutrients the plants can take in. As such, their growth and productivity will be affected.

He revealed that plastics in the environment are also very detrimental to animals, especially ruminants, such as goats and cattle.

"When they get to the stomach, they are like foreign materials and cannot be fully digested. Eventually, the animal dies," he said.

Agona added that burning the plastic materials is also dangerous because the fumes coming out are highly toxic and can cause cancer.

"There is also research that was conducted by NaFFIRI (National Fisheries Resources Research Institute), which revealed microfilms of the plastics in the fish population. The study showed that this was leading to slow fish growth and deaths of marine animals," Agona said.

According to him, this has been responsible for the drop in the catch numbers in the lakes, including Lake Victoria.

Agona said they have previously found many of these substances in especially small fish. He revealed that this is not only dangerous to the fish, but also to humans when they eat them.

Detected in foods

A 2018 report titled, "An underestimated threat: Land-based pollution with microplastics", which was done in Germany, said plastics were detected not only in fish and seafood, but also in salt, sugar and beer.

"It could be that the accumulation of plastics in terrestrial organisms is already common everywhere, the researchers speculate, even among those that do not "ingest" their food.

For example, tiny fragments of plastic can be accumulated in yeasts and filamentous fungi," the report added.

The intake and uptake of small micro-plastics could turn out to be the new long-term stress factor for the environment, the report said.

"At the moment, however, there is a lack of standardised methods for determining micro-plastics in terrestrial ecosystems in order to produce an accurate assessment of the situation," the report said.

"It is often a difficult and labour intensive process to detect tiny fragments of plastic particles in soils, for instance."

The study highlights the importance of reliable, scientifically based data on degradation behaviour and the effects of micro-plastics, in a bid to understand the extent of damage for the world to find workable remedies.

According to the study, when plastic particles break down, they gain new physical and chemical properties, increasing the risk that they will have a toxic effect on organisms.

And the more likely it is that toxic effects will occur, the larger the number of potentially affected species and ecological functions.

Chemical effects are especially problematic at the decomposition stage, as spotted by the team of authors, led by Anderson Abel de Souza Machado.

"For example, additives, such as phthalates and Bisphenol A, leach out of plastic particles. These additives are known for their hormonal effects and can potentially disrupt the hormone system not only of vertebrates, but also of several invertebrates.

"In addition, nano-sized particles may cause inflammation; they may traverse or change cellular barriers, and even cross highly selective membranes, such as the blood-brain barrier or the placenta. Within the cell, they can trigger changes in gene expression and biochemical reactions, among other things. The long-term effects of these changes have not yet been sufficiently explored. However, it has already been shown that when passing the bloodbrain barrier, nanoplastics (very tiny) have a behaviour-changing effect in fish," the report said.

Way forward

Agona revealed that NARO plans to come up with biodegradable plastics, which can be industrially made to replace the current plastics, especially the single plastic shopping bags, such as kaveera.

He said it is also possible, with further research, to introduce bacteria that are capable of naturally degrading the plastics.

"This is something research can look at. We have many trained scientists and academicians. It is just a matter of concentrating on the matter," he said.

Agona added that other interventions include implementation of the NEMA Act, particularly on banning plastics above 30 microns. He noted that Rwanda has demonstrated that this is possible.

Virchand M. Shah, a chemical engineer who has worked with plastics for over 40 years, proposes segregating waste, adding that this can help make a difference to Uganda's current problem.

"In some countries, you cannot mix all the different kinds of garbage in one place. If the government is able to enforce that, they will not only save the environment, but also earn money (through more taxes)," he said last week.

Citing the 2021 Greater Kampala Metropolitan Area report on plastics, he said only 9% of plastics are recycled.

"About 91% of plastic waste that cannot be processed is either going in the landfill or washed down to the lake. Some people are burning it, hence polluting the environment," said Shah, who is also the proprietor of Afloplastics.

In 2019, Uganda revised the environmental law (National Environment Act No.5 2019). The law prohibits plastic carrier bags under 30 microns.

Although some of these banned materials are still being manufactured and used widely in the country, Tony Achidiria, the NEMA senior public relations officer, said with the recently rolled measures, such as express penalty scheme (EPS) fines, they hope that many entities will be wary to continue flouting the law. This is because the fines will eat into their profits and make it costly to repeat offence.

They also want to ensure that producers of plastics take extended responsibility as part of the polluter to clean plastic waste from the environment.

Plastics are the main polluters in Uganda

From single-use plastic bags (kaveera) to ordinary jerricans used for fetching water in most homes in Uganda, to polyethylene terephthalate (PET) bottles in which we buy our mineral water, all plastics are known to harm the environment.

However, according to a 2021 study conducted under the Greater Kampala Metropolitan Area, PET Plastic Recycling Partnership, PET bottles take the number one position among environmental pollutants in Uganda.

This is because of the pervasive nature of PET bottles in the country's environment. Uganda has over 20 soft drinks and beverage companies.

Almost all of them still bottle some of their drinks in Single-Use Plastic products (SUPs) that are used once or for a short period and discarded.

The same report noted that about 79% of all plastic waste generated in Uganda is dumped into landfills or the environment, 12% is incinerated, and only 9% is recycled.

Alex Lwakuba, the commissioner for the crop production department, Ministry of Agriculture, Animal Industry and Fisheries, said despite the dangers, governments in Africa, including Uganda, have not given plastics much thought.

"We are naturally resilient in nature compared to other races on the planet and we do not take certain things seriously because the effects are long term," he said.

Lwakuba said the rise in unexplained ailments, including cancers, should be a welcome call that the issue of plastics is dangerous and needs to be attended to.

"Probably these (the rising cases of cancers in the country today) are a result of long term exposure to these persistent organic pollutants," he said.

Lwakuba added: "This is because overtime, these (pollutants) build up in the body. When they reach intolerable levels, they start causing effects that might be what we are seeing. We need to swing into action now and save our children. If we are not affected during our lifetime, our children should not be affected."

According to the Uganda Cancer Institute, the burden of cancers in Uganda will increase by around 40% in 2030.

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