"Biodegradable Plastic Bags, Not So Biodegradable"

Question

by Vicky Stein

The average person uses a typical plastic bag for as short a time as 12 minutes before throwing it away, never thinking of where it may end up.

Yet once consigned to a landfill, that standard grocery store tote takes hundreds or thousands of years to break down — much more than a human lifetime. Bags make up an alarming amount of the plastic found in whale stomachs or bird nests, and it’s no wonder — globally, we use between 1 and 5 trillion plastic bags each year.

Biodegradable plastic bags are marketed as more eco-friendly solutions, able to break down into harmless material more quickly than traditional plastics. One company claims their shopping bag “will degrade and biodegrade in a continuous, irreversible and unstoppable process” if it ends up as litter in the environment.

In a study published this week in Environmental Science and Technology, researchers put supposedly eco-friendly bags made from vari

Answer 1

ous biodegradable materials to the test. The findings shed light on the discrepancies between marketing claims and actual performance of these bags in real-world conditions.

The study involved placing biodegradable plastic bags alongside traditional plastic bags in different environments: a controlled lab setting, compost and soil, as well as marine environments. Over a span of several months, the researchers monitored the degradation rates of each type of bag.

The results were startling. While traditional plastic bags remained largely intact regardless of their environment, the biodegradable alternatives showed varying degrees of degradation. In lab conditions with optimal temperature and humidity, some bags began to break down as expected. However, in more realistic scenarios – such as soil and marine settings – the biodegradable bags either failed to degrade effectively or took much longer than anticipated, sometimes several years.

Moreover, some bags that were labeled as “biodegradable” contained additives that supposedly accelerated their breakdown. Yet these additives did not perform predictably, leading to uncertainty about their actual impact on the environment. In many cases, the partially degraded pieces still posed a danger to wildlife and ecosystems, as smaller fragments could be ingested by animals or contribute to microplastic pollution.

These findings raise critical questions about the marketing of biodegradable plastics. Consumers may be misled into thinking that using biodegradable bags is a sustainable choice, while in reality, the environmental benefits are limited. Advocacy groups stress the importance of comprehensive waste management solutions and urge people to reduce overall plastic consumption, opting for reusable bags instead.

In conclusion, while biodegradable plastic bags might seem like a positive step towards reducing plastic waste, the reality is far more complicated. As researchers continue to study these materials, it becomes increasingly clear that simply shifting from traditional plastics to biodegradable options may not be the solution we hoped for. The overarching message remains: to truly make a difference for the environment, we need to rethink our reliance on single-use plastics altogether.