In 2015, Richard Thompson, a British marine biologist, along with graduate students from the University of Plymouth, conducted a series of studies on biodegradable-labeled plastic bags which claimed to be biodegradable. This type of plastic is often found in supermarkets or shopping centers to wrap groceries.
This research has one purpose, to prove whether the two plastic bags are biodegradable?
They then placed a number of biodegradable plastic bags in numbers of locations. Some are buried in a school park, some are immersed in sea water, with a depth of 3 meters in the port of Plymouth.
Three years passed. The buried plastic bag was excavated and examined. Apparently, the plastic remains intact. It is even worthy of use and can withstand loads of up to 2.2 kilograms.
“It is surprising to me, that after three years you can still bring home groceries in it,” Thompson said to National Geographic. “They don’t have the same strength as when they were new, but they didn’t experience significant degradation.”
The findings immediately broke claims about biodegradable plastics, including compost plastics, which are called biodegradable. From the results of his research, Thompson concluded that no plastic can decay properly within three years. This research has been published in the journal Environmental Science & Technology.
Plastic bags are used in various parts of the world. Every year, the European Union is estimated to use around 100 billion bags, with annual per capita use exceeding 450 bags per year in several EU countries.
When the world seeks solutions to reduce the use of plastic bags, biodegradable plastics are present offering promises with claims that are easily biodegradable. Many people then switch to using this object. However, in some cases, biodegradable is not as sweet as the promise offered. That is, this plastic remains a threat to marine biota and can pollute the environment.
Both the United Nations and the European Union have actually expressed their opposition to the use of biodegradable plastics. In a report in 2016, the United Nations stated that biodegradable plastics were not the answer to dealing with plastic pollution in the ocean.
Last year, the European Union also recommended banning oxo-biodegradable. They consider additives designed to accelerate the breakdown of polymer molecules can harm the environment, where the process causes plastic bags to break down into microplastic, and could increase fears of micro-plastic pollution in the world’s oceans.
“There is no magic ingredient that can be damaged in a short time in all environments. Nothing,” said Ramani Narayan, a biodegradable chemist and expert at Michigan State University.
Narayan then criticized Thompson’s research and the University of Plymouth regarding compost plastic called also not easily biodegradable. According to him, the compost plastic used by Thompson in his research was actually not designed to last long. US industry regulations recommend that plastic compost be disposed of in composting.
“Compost plastics can only biodegrade naturally in the industrial composting environment and are intended to be disposed of in the environment,” Narayan said, quoted by National Geographic.
On the other hand, the largest producer of oxo-biodegradable products in the UK, Symphony Environmental Technologies, explained that oxo-biodegradable is not intended to be degraded in landfills or drowned in the ocean.
“In contrast, oxo-biodegradable bags are intended to decompose in the open or at sea level. Oxo-biodegradable plastic also contains stabilizers that make plastic more useful and can last up to 18 months, “said Michael Stephen, deputy chairman of Symphony Environmental Technologies.
Furthermore, said Stephen, when the stabilizer has run out and the product reaches the end of its useful life, the catalyst will begin to decline. The time of degradation in biodegradable plastic also varies, for example in warm environments, the plastic will decompose within one year. In a humid and cold environment, it may take two to three years.
The degradation of biodegradable plastics is judged to be much faster than conventional plastic. Where, Stephen thought that conventional plastic might take up to 100 years. “Do you want two years or a hundred years,” he said.
Thompson and the University of Plymouth team, stressed that the research he conducted should not be concluded as an argument against the development of biodegradable or compost. Instead, this study argues to rethink which products are most suitable as biodegradable. “We have to connect these products with the right use,” he said.
In the environment of soccer stadiums for example, it might be more suitable with compost plastic products. Disposable food wrapping containers or leftover food items can be collected in one place, and the waste is processed in industrial composting.
Thompson suggested that people continue to use products or shopping bags that can be used repeatedly.