Are all single-use plastic bags the same? Do they have the same impact on the environment? Are biodegradable bags better than non-biodegradable? Are paper bags better than biodegradable plastic bags?
First things first; before focusing on the material we have to focus on the product, i.e. the best is to avoid disposable bags whenever possible. Remember: prevention is always the best option! Before the invention of plastic bags this waste stream was absolutely insignificant –composed only of those reusable bags that broke after years of use and could not be mended.
Therefore, the discussion on whether a biodegradable plastic bag is better than a non-biodegradable one is as important as it is secondary. First option is reduce, second option is recycle, third –and a sign of the inneficiency of our society- is disposal. Replacing a single-use plastic bag by a single-use biodegradable plastic-bag is not the solution, although it may help reduce the overall impact and pressures on environment.
Biodegradable vs non-biodegradable
If we have to choose between a single-use plastic bag and a single-use biodegradable plastic bag some studies claim that the bio-degradable plastic bags have a higher environmental impact but they are highly missleading. This is because of weak science; they do not consider the ecotoxicology and eutriphocation aspects of plastic. Moreover there is the problem that in these studies and other Life Cycle Assessments they tend to neglect the benefits of composting (which is the primary route for post-use management of biodegradable bags) by not integrating the positive role on soils.
EU-ban on single-use plastic bags
Some countries in Europe have taken different measures to tackle the burden of single-use plastic bags. It is only recently that Janez Potocnik, EU Commissioner for Environment has announced that the EU will study an EU-ban for single-use plastic bags.
A ban on any single-use plastic bag in the EU is a great idea but it should be handled with care to make sure that the biodegradable bags which will replace the current single-use plastic bags are truly biodegradable -i.e. they do not just “fragment”-. This ban should be accompanied with clear reduction targets in terms of single bag units put on the market.
Therefore, an European ban on plastic bags could work if the rule would concurrently state that by biodegradable bags we understand those that follow the European Norm 13432. This EN 13432 requires biodegradation of 90% of the materials in a lab testing within 180 days (of course, the fate of part of bioplastics is to be turned into compost at a compost site). However, more stringent criteria may be considered to ensure this biodegradability can also happen in home composting (some bioplastics degrade well also in home compost heaps, others more slowly) and marine environment.
Having serious standards of biodegradability is essential to make a difference between biodegradable and non-biodegradable. Indeed some so-called “degradable plastics”which do not comply with EN 13432 (e.g. exo-degradables) just break into tiny pieces the size of plancton that do not decompose and end up in the food chain when they are eaten by fish or other animals . Some others do decompose properly but too slow to be composted with food waste, which makes them end up into rejects at the compost site.
Moreover there are very special cases when a single-use really bio-degradable plastic bag could be justified and , to some extend, also very helpful: i.e. to take out the organic waste separately and ease the separate collection of this waste-stream. If the bag is really biodegradable (for instance 100% corn-starch or potato-peel starch complying with EN13432, or also paper bags) it will not create problems in the composting plant and it will fully decompose in the process. This is being used succesfully by more than 20 million Italian and Spanish citizens, mainly in those municipalities doing door-to-door separate collection collection system, and helps achieving hihest captures, reduced percentatges of organics in residual waste, and subsequent operational optimisation. But this is probably the only exception that justifies single-use bio-degradable plastic bags.
All in all it would be very useful if the European Commission could show more than simpathy for the 3rd International Bag-free day and would produce a clear rule as to how to phase out single-use plastic bags. In order to do so it is necessary to associate the ban to EU-wide prevention targets and when necessary even taxation. The funds collected with a tax on single-use plastic bags could be used to finance alternatives and clean the damage done by plastic bags in land and sea.
For the moment it is a fact that single-use plastic bags are bad for the environment (unless they are really biodegradable and deemed as a tool to optimize separate collection) and the economy and that many European countries started to take measures to reduce its use, it is also a fact that reusable bags look a lot nicer and trendier than single-use plastic bags. The environmental awareness in Europe is starting to get single-use plastic bags out of the way and prepare the path towards a Zero Waste society.