They have managed to identify a high level of toxicity in compostable plastic bags, so they are not as environmentally friendly as many claim.
If you thought that using compostable plastic bags was a great help to the environment and even to health, this new study leaves many of the bags that we use every day in a very bad place.
And to do this, the researchers analyzed three types of bags, a compostable bag made of vegetable starch, a bag of plastic recycled and other conventional plastic bag.
They then exposed them to sunlight to decompose and turned them into compost, testing the toxicity of the resulting compost on different cells.
According to what is stated, the bags produced “a high level of toxicity,” comment the authors from the Higher Council for Scientific Research (CSIC).
Journal of Hazardous Materials
“We were surprised that cells exposed to conventional plastic bags showed no traces of toxicity,” he says. Doorslead author of the study, published in the Journal of Hazardous Materials.
“However, we did detect it in biodegradables, which decreased cell viability. Our hypothesis is that manufacturers add chemical additives to make biodegradable bags that could be especially toxic,” he adds.
“In addition, the plastic bags Recycled materials also showed higher levels of toxicity than conventional ones, since plastic additives are also added for reuse,” he explains.
He adds that the chemical compounds added to the compostable bags were not identified due to patent issues.
They comment that it is quite likely that they are plasticizers, that is, compounds added to plastic to make it more flexible.
The study tested four types of compostable bags: made of polybutylene adipate teraphthalate and starch, a single-use water bottle made of PET (polyethylene teraphthalate), a conventional plastic bag made of LDPE (low polyethylene density) and two garbage bags made of recycled polyethylene.
“This work demonstrates the high toxicity of recycled plastics, compostable plastics and semi-degraded compostable plastics resulting from partial disintegration, compared to conventional virgin plastic extracts,” they comment.
“These findings underscore the need for additional research efforts and the implementation of regulatory measures prior to the release of mature compost into the environment,” they conclude.