Hospital waste, not masks, are plastic threat of pandemic: study

A new study has found that 26,000 metric tons of pandemic-related plastic waste has been released into the world’s oceans since the start of the Covid-19 pandemic in January 2020.

hospital plastic indonesia
A hospital worker covering a piece of equipment with plastic at an Indonesian hospital. Image: ILO/F. Latief, CC BY-NC-ND 2.0.

The disposable face mask has become the poster child for Covid-19-related waste since the start of the pandemic, showing up on beaches and in waterways all over the world. Hong Kong is no exception. Just a few weeks after the first cases hit the city, face masks started appearing in the ocean and washing onto beaches, says Gary Stokes of Hong Kong-based NGO OceansAsia.

“You can go down into the main bit of Hong Kong Harbor, be waiting for a ferry or looking over the promenade, and you’ll just see them floating past,” Stokes told Mongabay in a phone interview. “Then you can go all the way out to … the Soko Islands, which is remote and … away from everybody, and you still find them there.”

But discarded face masks are only the most noticeable form of pandemic-related plastic waste impacting the marine environment. A new study published this week in Proceedings of the National Academy of Sciences (PNAS) found that pandemic-related hospital waste — plastic sheets, bottles, syringes and gloves — posed a far greater threat than the 1.56 billion face masks estimated to have already made their way into the oceans.

The study used modeling to find that 193 countries produced more than eight million metric tons of pandemic-related plastic waste since the start of the Covid-19 outbreak. About 26,000 tons of this waste is said to have already been released into the ocean, where it can threaten marine wildlife through entanglement and ingestion.

The vast majority of this plastic waste, about 87 per cent, is produced by hospitals, while only seven per cent comes from personal protective equipment (PPE), according to the study. The paper also looked at disposable plastic used in online shopping and Covid-19 test kits, but these are said to only account for 4.7 per cent and 0.3 per cent respectively.

“Hospitals are the new hotspots,” study co-author Yanxu Zhang of China’s Nanjing University told Mongabay in a video interview. “It was very surprising to us because we already read some previous studies or news articles about face masks.

So we first thought that the personal protection equipment was probably the largest contributor [to pandemic-related plastic pollution], especially considering the huge amount of usage, not only by the patients but by everybody. Well, after we carefully evaluated our data, we realised that’s not the case.”

The study suggests that more than 72 per cent of the mismanaged waste comes from Asia, despite the region only experiencing 30 per cent of worldwide Covid-19 cases. Europe is thought to have produced about 11 per cent of mismanaged pandemic-related plastic, while North America produced only 1.9 per cent.

Zhang said most of the mismanaged plastic waste was coming from developing countries that lacked adequate waste management. He said these were often the same countries that experienced high numbers of Covid-19 cases and where vaccines weren’t readily available.

Most of this pandemic-related plastic waste will enter the ocean through river systems, the top three being the Shatt al-Arab in Iran, the Indus and Yangtze river systems, the study says. By the century’s end, “almost all the pandemic-associated plastics” will end up on beaches or the seabed, according to the researchers.

While the amount of pandemic-related plastic waste pouring into the ocean is concerning, Zhang says it is only a “fraction” of what is already there. According to a 2015 study, there are more than 5.25 trillion pieces of plastic in the marine environment. This amount is increasing as plastic production continues to rise.

When plastic enters the ocean, sunlight, oxidation, friction or even animals break it into smaller pieces. Anything smaller than five millimetres (about three-sixteenths of an inch) is considered a “microplastic.”

Research shows that some microplastics float on the surface, while others will travel with the currents through the ocean and settle on the seafloor. Microplastics in the ocean will even enter the atmosphere through the propulsion of waves and sea spray, research shows.

While many plastics are touted as “safe,” they can actually be made from an array of toxic chemicals and additives, such as polyvinyl chloride (PVC), which has been linked to cancer cases in humans, and bisphenol A (BPA), which is known to be an endocrine disrupter.

“When we talk about plastics, we have this misconception that plastic is just one thing,” Patricia Villarrubia-Gómez of the Stockholm Resilience Centre told Mongabay in a video interview. “But in reality, there are hundreds of different kinds of plastics that are made up of thousands of different kinds of chemicals and additives that give …. each plastic its own properties. So in many cases, we don’t know which chemicals are in those plastics. The industry does not provide that information.”

In many cases, research regarding potential harm from these thousands of chemicals has not been done, which could lead to unpleasant unforeseen toxic surprises in future, long after the oceans have been polluted with them.

What’s more, plastic is known to act as a sponge for other toxic chemicals present in the ocean, heightening plastic’s own toxicity and potentially poisoning any animal that ingests it. A 2017 report published by the UN Food and Agriculture Organisation (FAO) found that fish and other marine animals that had high concentrations of microplastics in their respiratory and digestive tracts experienced increased mortality.

Less is known about plastic’s effect on human health, but many researchers suspect that plastic could negatively affect our health if enough of it accumulates in our bodies. Evidence is still emerging, and more research is needed, as to the health impacts of ingesting microplastics on shellfish and fish, and on humans who eat seafood.

Besides threatening marine life and possibly even human health, researchers consider plastic to be a novel entity that has the potential to alter the dynamics of Earth’s life support systems. Novel entities are one of the nine planetary boundaries that help regulate life on Earth, but have a limit for how much pressure they can sustain from anthropogenic activities before becoming seriously destabilised.

Up to this time, scientists have yet to determine a threshold for the novel entity boundary. However, many experts agree that plastics are among the many synthetic entities within this boundary that pose a substantial threat to the optimal functioning of the Earth.

Villarrubia-Gómez says the increase of pandemic-related plastic waste could not only put additional pressure on the oceans, but could contribute to atmospheric microplastics.

“I’m personally concerned [about] what’s going to happen with the masks,” she said. “[Masks have] a type of fiber that sheds and … maybe it [will increase the] microfibers seen in the atmosphere.”

Plastic is also known to impact the climate change planetary boundary due to the large amounts of greenhouse gases that are emitted during plastic’s entire life cycle — from the extraction of raw materials to manufacturing to disposal. 

Recent research even shows that atmospheric microplastics are impacting cloud reflectivity — both subtly cooling and warming Earth’s climate, depending on circumstances. However, the microplastic particles are so varied in size, shape and color it is too early to know what their ultimate atmospheric effects may be.

Clearly, plastic waste is having a substantial impact on the natural world, and research shows that the Covid-19 pandemic is exacerbating the problem. However, Zhang says he hopes that his paper in PNAS will help shine a light on the seriousness of the issue, and even help encourage governments to enforce stricter policies that address the mismanagement of waste — a plastics global treaty could even be in the works in 2022.

“We want our paper to raise public awareness,” he said, “[and for] policymakers to know that there is a price or side effect of this plastic industry as we fight this disease.”

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