Researchers surprised by toxicity levels of standard plastic products

The plastics around us contain a range of chemical additives that can leach into water systems in the natural environment. This can happen before and during the plastic degradation process. Even though the product takes a long time to break down into microplastic particles, chemicals start leaching out of the plastic as soon as they enter the water.

Researchers have been trying to learn more about whether this phenomenon is harmful to animals and perhaps humans as well.

“In this project, we have been focusing on the impact of chemical additives in plastics on marine life,” said Lisbet Srensen, research scientist at SINTEF Ocean. “To do this, we have been studying various marine species. During the first screening, we examined two groups of microorganisms – bacteria and microalgae, also known as phytoplankton. These species are easy to handle and gives us a quick answer that we can use to help us plan future research directions,” she said.

“Later, we studied cod eggs and larvae, which are one of our most important natural resources,” Srensen said. “We know very well that fish, like humans, are more susceptible to the health effects of pollution when they are immature,” she explains.

Fifty daily necessities

“Of course it’s impossible to test every plastic product available, so we conducted a ‘qualified selection’ of 50 products used in daily life,” says Srensen.

The 50 products include plastic bags, disposable cups, dishwashing gloves, car tire pellets, various children’s toys and balloons. This is just the beginning.

“The original idea was just to go with ‘classic’ plastic products, but I gave in to temptation and went with something made of rubber,” says Srensen. “It turned out to be a wise decision,” she said.

What happens when plastic breaks down?

The MicroLEACH program is executed by an interdisciplinary team of international research scientists, including biologists and chemists. MicroLEACH stands for Microplastics The long-term effects of plastics and additive chemicals on marine life.

Analytical lab work gives the team a broad understanding of the types and amounts of chemicals found in various products.

“We were very surprised by the number of different chemicals found in these products,” Srensen said. “Only 30% of the identified compounds are present in two or more products. There are also a large number of chemicals that we cannot identify because they are not listed in established substances indexes. This tells us how little we know about the things around us. Ingredients in many everyday products,” she said.

The purpose of this project is purely to investigate how toxic these chemicals are to living organisms once plastic products enter the marine environment. In recent years, people have mainly focused on issues related to microplastics. When plastics are broken down into physical fragments or break down chemically due to environmental factors, they eventually become microplastic particles. However, long before this process is complete, chemical additives in the plastic can leak into the natural environment.

“We hope to solve this problem in the MicroLEACH project,” said Andy Booth, chief research scientist at SINTEF. “The question is: How toxic are the chemical additives we find in standard plastic products on the Norwegian market, and how problematic are they compared to the microplastics produced by the products themselves?” he said.

Booth has spent years studying ocean pollution and what happens to nanoparticles that enter the marine environment.

Natural rubber is far from harmless

The research team studied the effects of chemicals leaching from microplastic and rubber particles into the marine environment.

“We found that products that were composed of or contained high levels of rubber had the worst effects on the microorganisms we studied in our experiments,” Booth said. “This is somewhat surprising, especially since untreated rubber is considered a ‘natural’ product. However, we found that it is one of the most toxic substances to the microorganisms we were studying,” he said.

The worst part is the chemicals that seep out of the rubber gloves.

“It’s worth noting that chemicals added to natural rubber and used in dishwashing gloves have been shown to be the most toxic to microorganisms,” Booth said. We found four substances in 50 products we tested, including dishwashing gloves, car tires, rubber balloons and disposable gloves,” he said.

Deformed fish larvae

Further research under the project involves exposing cod embryos and recently hatched larvae to microplastic particles and chemicals found in plastic. The team also exposed eggs and larvae to a combination of the two, since in the real world they are indistinguishable from each other.The team has presented its findings in an article published in the journal Science Hazardous Materials Magazine, Marine Pollution Bulletin and Total Environmental Science.

Initially, the researchers characterized and extracted toxic chemicals from various plastics and studied their effects on cod larvae.

“We observed that some chemicals directly prevent the eggs from hatching, while others have significant physical effects on the larvae,” says Stefania Piarulli, biologist and research scientist at SINTEF. “We found that the larvae developed spinal deformities that reminded us of what is known as scoliosis,” she said.

Which is worse, microplastics or chemicals?

But what about microplastic particles? Are they harmful in their physical state, or is it a combination of their size and the chemicals leached from them that make them so toxic?

To study this, the researchers compared the effects of particles and chemicals separately, and were somewhat surprised to find that the chemicals were crucial in producing the toxic effects.

“The peculiarity of this experiment is that we developed a completely new method to ‘remove’ all traces of chemicals from microplastics,” Piarulli explains. “This is the only way to determine the impact of microplastic particles,” she said.

In other words, the team found that if the physical particles were chemical-free, there would be no toxic effects.

Flexible plastics are unique

The research team found that not all types of plastic are toxic. The combination of different plastic products determines the level of toxicity, with elastomeric products proving to be the worst.

“This means we now know that the toxicity of many products can be reduced simply by choosing alternative polymer combinations during the manufacturing process,” said Andy Booth.

“It’s worth noting that chemicals added to natural rubber and used in dishwashing gloves have been shown to be the most toxic to microorganisms.

What about mammals and humans?

Biologist and researcher Stefania Piarulli is a member of the task force and has been responsible for experiments involving marine life.

Is there any reason to believe that food animals such as wild and farmed fish, chicken, pork, or beef contain many of these chemicals? “Humans and other animals are constantly exposed to macroplastics and microplastics and the chemical additives they contain,” Piarulli explains.

“So it’s natural to assume that we are also exposed to chemical additives associated with plastics through the food we eat. But we need more research to find out how many of these chemicals come from meat products and how many come from meat products.” Packaging,” she said, adding:

“My point is that we are exposed to far more chemicals during food processing and cooking than plastic packaging. We are also exposed to chemical additives associated with plastic in many other ways,” Piarulli said.

Research team member Lisbet Srensen added that fortunately, plastic products used for food storage and consumption are the least problematic. Virtually all so-called “food contact materials” are governed by a strict set of regulations that set limits on the content of identified and unidentified chemical additives.

“Even more concerning is that other plastic products we use every day, including some designed for children, did not perform as well as food contact materials in our experiments,” Srensen said. However, we must also emphasize that in this project we have not studied any effects that are directly applicable to humans,” she said.

As a researcher, what advice can you give consumers when it comes to plastics and food? “Never in history have we had more pollution than we do today,” said Stefania Piarulli. “That’s why we should always be working to reduce our use of plastic. We know plastic has adverse effects, and we also know there are likely to be effects we haven’t discovered yet, including direct effects on terrestrial, fresh, and marine environments. ,”she says.

“Plastic is a very beneficial invention that in many cases is critical to the way we live our lives, especially in the fields of medicine and certain types of packaging,” Piarulli said.

“But plastics are also used in many completely unnecessary contexts, such as in the textile industry and in the over-packaging of products. Perhaps the most important thing to remember is to avoid plastics wherever possible and use our influence as consumers when When we buy new products,” she said.