OSLO, Feb. 20 (Xinhua) -- Researchers from the Norwegian national research institute Ostfoldforskning have criticized the use of biodegradable plastics, saying they are also harmful to the environment, newspaper Aftenposten reported Tuesday.

"Biodegradable plastics help in luring the consumer to believe that they can be thrown into nature because it is perceived that they will disintegrate completely and disappear, which is incorrect," four researchers from Ostfoldforskning wrote in article published in Aftenposten.

According to them, some plastics that are nowadays marketed as so-called "bioplastics" contain a relatively high proportion of fossil plastic.

When companies document the degradability of their products, they do so according to the international standards for testing of compostability and biodegradability.

Test conditions, however, are far more favorable than they are in nature, which means the actual bio-degradation time in nature will be significantly longer, the researchers claimed.

"This means that a large part of the 'biodegradable' plastic that originates in nature will initially pollute nature as plastic waste, and then disintegrate into micro-plastic with the potential to create further environmental problems," the scientists wrote.

People should not think that so-called "biodegradable" dog bags can be thrown into nature because they disintegrate and "disappear," they said.

Biodegradable plastic can not be recycled and thus cannot be part of the circular economy, the researchers said, adding that it can, however, be suitable for very specific purposes, such as packaging food waste intended for biological treatment.

Real bioplastic, on the other hand, can be a sustainable alternative to fossil plastic, and can thus play a role in the green shift, the researchers wrote, emphasizing the need for more research in this area.

"Regardless of type or origin, the most important thing is to ensure that plastic does not end up in nature, but is collected and handled in a resource efficient manner. This contributes to reduced littering, efficient resource management and a circular economy," the researchers said.