There are no great solutions to the problem of throwaway plastics. They can clog up landfills for centuries, or get dumped into rivers and break down into toxic microplastics. Incineration produces greenhouse gases and air pollution, and recycling often results in less valuable, \u201cdowncycled\u201d forms of plastic.<\/p>\n
Biodegradable plastics, which can be composted in industrial facilities or broken down into biogas and nutrient-rich fertilizer through anaerobic digestion, have been seen as a way out of this conundrum. But the truth is more nuanced, according to a new analysis.<\/p>\n
The comprehensive study, the first global-scale analysis of the environmental impact of biodegradable plastics across the entire life cycle, reveals huge potential to decrease the environmental impact<\/a> of the global plastics industry\u2014but only with careful attention to proper disposal. In other words, biodegradable plastics aren\u2019t a license to litter\u2014or even just to dump plastic waste in the landfill.<\/p>\n An estimated 25-46% of conventional plastics could be replaced by biodegradable ones. Substituting biodegradable for conventional plastics where possible would reduce global plastic waste accumulation 27% by 2050, the researchers calculated.<\/p>\n But even in that scenario, there would still be a lot of conventional plastics in the system, so better disposal systems for conventional plastics are still important. It\u2019s possible to reduce plastic waste accumulation by as much as 65%, the researchers found\u2014if, in addition to the rollout of biodegradable plastics, as much conventional plastic as possible is routed away from landfills<\/a> and incinerated or recycled instead.<\/p>\n \u00a0<\/p>\n \u00a0<\/p>\n Biodegradable plastics are designed to break down in specific conditions, which might or might not pertain in landfills. So if biodegradable products get tossed in landfills, either they will break down and produce the powerful greenhouse gas methane\u2014possibly as much as doubling the climate impact of the global plastics industry\u2014or they won\u2019t break down, which could actually wind up increasing the total accumulation of plastic waste.<\/p>\n Microplastics formed from biodegradable plastics are less toxic than those formed from conventional plastics\u2014but not totally non-toxic. Overall, biodegradable plastics could reduce aquatic toxicit<\/a>y from the global plastic industry by about one-third, the researchers calculated. The best solution, of course, is to keep all kinds of plastics out of the environment to prevent microplastic formation in the first place.<\/p>\n Biodegradable plastics can\u2019t be recycled and conventional plastics (of course) can\u2019t be composted. \u201cBiodegradable plastic waste must be collected separately from conventional plastic waste, which requires capacity expansion of waste collection systems and consumer education,\u201d the researchers write.<\/p>\n Not only will we need to build waste management systems that can handle the growing complexity of plastics, but the general public will also need to know how to recognize biodegradable plastics and how to dispose of them\u2014highlighting how difficult it is to engineer out the human element from the act of throwing things away.<\/p>\n