Microplastics strengthen the toxicity of pollutants

Microplastics in the marine environment absorb pollutants and increase their toxicity by a factor of 10, according to a new study from Tel Aviv University. This increased toxicity could be a threat to human health, potentially causing severe damage to the digestive system.

The research was conducted by Dr. Ines Zucker of the TAU Porter School of the Environment and Earth Sciences, in collaboration with Ph.D. student Andrey Eitan Rubin. 

Dr. Zucker said the study shows that even very low concentrations of environmental pollutants, which are non-toxic to humans, significantly increase in toxicity once they have been absorbed by microplastic. “This is because microplastics are a kind of ‘magnet’ for environmental pollutants, concentrating them on its surfaces, ‘ferrying’ them through our digestive tract, and releasing them in a concentrated form in certain areas – thus causing increased toxicity.”

The study authors explained that since plastic is not a natural material, it decomposes very slowly in nature, in a process that sometimes endures for thousands of years and, as part of this process, the same microplastics are formed.

The researchers examined the entire life cycle of microplastic, including the interactions that plastic particles have with environmental pollutants, as well as the release of these pollutants. The results suggest that by the time the pollutants are released, they are much more toxic, and pose a threat to humans who consume contaminated food or drinks.

“For the first time we are presenting a complete ‘life cycle’ of microplastics: from the moment of their release into the environment, through the adsorption of environmental pollutants and up to their joint toxicity in humans,” said Rubin.

“The amount of waste dumped into the ocean every year is enormous – the best known example is the plastic island in the Pacific Ocean, which has an area 80 times larger than the State of Israel. But this is not just a remote problem – from our preliminary monitoring data show that Israel’s shores are among the most polluted with microplastic waste.” 

“Each of the microplastic particles secreted in these areas has tremendous potential for harm as they serve as an effective and stable platform for any pollutant that they may encounter on their way to the human body.”                                                                                                                  

“We have found that the adsorption capacity of an oxidized microplastic particle (the configuration of the microplastic after undergoing environmental weathering) is significantly higher than a non-oxidized particle,” said Dr. Zucker.

“After the environmental pollutants adsorb to the microplastic, the pre-loaded particle may reach the digestive tract through the ingestion of contaminated food and water where it releases the toxins in close proximity to the cells of the digestive tract, thus increasing the toxicity of these substances. This is another painful reminder of the dire consequences of polluting the marine and terrestrial environment with hazardous industrial waste, which has unfortunately been saturated with plastic in recent decades.”

“The dangers are not theoretical but are more tangible than ever. Although there is a great deal of awareness of this problem, the preventive measures in the field are still far from imprinting a significant mark.”

The study is published in the prestigious journal Chemosphere.

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By Chrissy Sexton, Earth.com Staff Writer