by Mike Conner
The following are my opinions, based on a good bit of reading but not rigorous research.
Paper, steel, modern-tin, aluminum, and glass cause minimal harm if they are “lost” into the environment. (Roadside non-plastic trash is more an esthetic issue than an environmental issue.) Many chemicals and metals are also harmful, but these should not be present in household recycling.
Plastic on the other hand causes lots of problems if it is “lost” into the environment.
Tiny, micro, and nano particles of plastic are polluting our food, soil, and water to a remarkable extent. Much of this comes from Styrofoam which quickly breaks down into micro pieces that don’t further decompose. A lot comes come coatings that break down into “forever” chemicals. Pretty much all plastic breaks down in the ocean into smaller and smaller pieces, but these pieces remain plastic; they don’t decompose.
Plastic film, complex shapes (like the harness for a six-pack of cans, or a net, or a tangle of string or rope), and small, swallowable parts are causing lots of harm to wildlife, especially in the oceans.
Plastic recycling barely works. Most estimates guess that only about 10% of recycled plastic is actually recycled and the rest is discarded. Actually, the percentage is much lower for everything but standard plastic drink bottles. Plastic bottles are more readily recycled because they are easy to identify and because they are all made from the same somewhat-recyclable plastic. Note that they are, sadly, not very reusable, as cleaning them causes them to start leaching chemicals into their contents.
In North America (including the USA) there are essentially no open public trash dumps. Here we have landfills, which are regulated, and modern ones are quite well designed and managed. The rest of the world, and especially the countries to which recycling materials are shipped, still heavily rely on open trash dumps, many located near rivers. These dumps, plus fishing fleets, account for most of the plastic that pollutes many rivers and all oceans.
In the US it seems that the processing stream for recycled plastic is poorly documented, but it is estimated that about 40% of US recycled plastic is still shipped overseas. So, when you recycle plastic, you have two possibilities:
1) It gets sent to a US-based recycler, where a small percentage is recycled, and most is disposed of in a well-managed landfill. In this case, you have increased the energy cost of disposing of your plastic with the benefit that some may have been saved from going into a well-managed landfill.
2) It gets shipped overseas, where the vast majority of it will end up in an open dump, and a good fraction will end up polluting the environment.
So, my conclusion is that we should recycle everything we can (especially things like electronics that contain heavy metals and bad chemicals) except plastic. I think the case for recycling plastic drink bottles is borderline, but for everything else it is better to put plastic in the trash. And, of course, we should avoid single-use plastic when reasonable to do so. (The case for some plastic packaging (like shopping bags and containers) is complex, as sometimes the environmental cost of non-plastic packaging is considerably higher.)
And always remember that recycling is the last term in — reduce, reuse, and recycle.
An article with some interesting background information about landfills and municipal recycling is: This California city asked where its recycling went. The answer wasn’t pretty.