You may have heard that the ocean is full of plastics, and while full is an excessive word, there are huge amounts of plastics there, thanks to humans inability to look after some things when they have finished using them. Homo litterus is what we are. You may even have heard that these plastics degrade in light, and form microscopic particles that are having an adverse effect on the fish population. If that is it, as they say, “You aint heard nothin’ yet.”

According to an article in the Proceedings of the National Academy of Science, there is roughly 1100 tons of microplastics in the air over the Western US, and presumably there are corresponding amounts elsewhere. When you go for a walk in the wilderness to take in the fresh air, well, you also breathe in microplastics. 84% of that in the western US comes from roads outside the major cities, and 11% appear to be blowing in from the oceans. They stay airborne for about a week, and eventually settle somewhere. As to source, plastic bags and bottles photodegrade and break down into ever-smaller fragments. When you put clothes made from synthetic fibers into your washing machine, tiny microfibers get sloughed off and end up wherever the wastewater ends up. The microplastics end up in the sludge, and if that is sold off as fertilizer, it ends up in the soil. Otherwise, it ends up in the sea. The fragments of plastics get smaller, but they stay more or less as polymers, although nylons and polyesters will presumably hydrolyse eventually. However, at present there are so many plastics in the oceans that there may even be as much microplastics blowing out as plastics going in.

When waves crash and winds scour the seas, they launch seawater droplets into the air. If the water can evaporate before the drops fall, i.e. in the small drops, you are left with an aerosol that contains salts from the sea, organic matter, microalgae, and now microplastics.

Agricultural dust provided 5% of the microplastics, and these are effectively recycled, while cities only provided 0.4%. The rest mainly come from roads outside cities. When a car rolls down a road, tiny flecks come off the tyres, and tyre particles are included in the microplastics because at that size the difference between a plastic and an elastomer is trivial. Road traffic in cities does produce a huge amount of such microplastics, but these did not affect this study because in the city, buildings shield the wind and particles do not get lifted to the higher atmosphere. They will simply pollute the citizens’ air locally so city dwellers merely get theirs “fresher”.  Also, the argument goes, cars moving at 100 k/h impart a lot of energy but in cities cars drive much more slowly. I am not sure how they counted freeways/motorways/etc that go through cities. They are hardly rural, although around here at rush hour they can sometimes look like they think they ought to be parking lots.

Another reason for assigning tyre particles as microplastics is that apparently all sources are so thoroughly mixed up it is impossible to differentiate them. The situation may be worse in Europe because there they get rid of waste plastics by incorporating them in road-surface material, and hence as the surface wears, recycled waste particles get into the air.

Which raises the question, what to do? Option 1 is to do nothing and hope we can live with these microplastics. You can form your own ideas on this. The second is to ban them from certain uses. In New Zealand we have banned supermarket plastic bags and when I go shopping I have reusable bags that are made out of, er, plastics, but of course they don’t get thrown away or dumped in the rubbish. The third option is to destroy the used plastics.I happen to favour the third option, because it is the only way to get rid of the polymers. The first step in such a system would be to size reduce the objects and separate those that float on water from those that do not. Those that do can be pyrolysed to form hydrocarbon fuels that with a little hydrotreating can make good diesel or petrol, while those that sink can be broken down with hydrothermal pyrolysis to get much the same result. Hydrothermal treatment of wastewater sludge also makes fuel, and the residues, essentially carbonaceous solids, can be buried to return carbon to the ground. Such polymers will no longer exist as polymers. However, whatever we do, all that will happen is we limit the load. The question then is, how harmless are they? Given we have yet to notice effects, they cannot be too hazardous, but what is acceptable?


7 thoughts on “Microplastics

  1. I’ve wondered why plastic waste that can’t be recycled isn’t turned into energy by burning or similar processes. I gather one reason is that burning produces toxic air pollution. But it’s ironic that we’re all breathing in microplastics, already.

    • Simply burning them “as is” is polluting, especially if there are polyurethane items there because they can produce cyanides. If you try to burn pvc you generate hydrochloric acid. If you burn ordinary plastics the temperature is not high enough to burn them properly. What happens is they melt and form large globs but these can’t mix properly with the air.

      If, however you separate them and pyrolyse them, including hydrothermally, by breaking down the molecular weight you get a much better fuel, and if you get liquid ones under the right conditions you get excellent petrol or diesel, and the heavy ends would be appropriate for ships.

  2. A private school decided to destroy its natural grass lawns, and replace them with plastic fake grass, 2 years ago. We protested, produced a 200 page report explaining the dangers. We were told that, if we said another word, to anyone about this, our daughter, nine years old, would be thrown out of her Franco-American school. And so they did. They kept next year’s money. The guy who directed the effort for the plastic fields he was invested in, is a heir of a major tech fortune, a household name. His wife headed the school board.

    The plastic investor is also a major adviser in ecology for Macron and the Democrats, and is on a first name basis with “Bill”, “Warren”, “Rich”, “Mark”, etc… The masters of the world. The “ecologist” has two mansions in Lake Tahoe alone (and a fleet of electric cars). He announced to me that my daughter (a A+ student) was kicked out because her parents had made allegations to the principal. The idea of the “ecologist” was to cover all schools with plastic. Meanwhile, the EU has ordered dismantling all such fields, now outlawed…

    Did you look at the Biden climate thingie?

    The obsession with electric battery cars is curious if the aim is to reduce the ecological load on the planet, because it does not. Batteries, as they are, are made of a number of fundamental elements which require vast pollution to extract. Consider the lawsuits by ecologists, because one lithium mine was allowed in Nevada. The mine will require a lot of water and sulfuric acid. Local Native Americans approved it, but politically correct ecologists are incensed: extracting lithium should only be done overseas. Lithium batteries are no way to store electric energy, on a gigantic mass scale. The planet cannot afford to produce 100 million electric cars a year, and world industry simply cannot do it.

    What could be done is to use “green” hydrogen. That can be stored, especially under diverse derivative forms, and harness existing networks, like the natural gas pipe network (CH4 and H2 can be mixed). But of course, once 174 billions have been wasted on an ecological disaster (electric battery cars), there will be no money to develop “green” hydrogen (which works very well with fuel cells… which enabled us to go to the moon…)
    More fundamental research is needed to invent new energy sources which could be deployed worldwide: new fission, fusion, “green” hydrogen and derivatives, fuel cells, better solar cells, etc. Because we need to deploy carbon free energy worldwide. Hyper expensive lithium-rare earth batteries won’t do it… Because an electric car pollutes as the source of energy which produces the energy does. As it is, amazingly only 2% of the total energy used in California comes from renewables. There is no storage capacity, and a giant fossil fuel industry is the backbone of California.

    Greenhouse Crisis: No New Science, No Progress. Where Is The Science in Biden Climate Project? 

    • Hi Patrice,

      Yes, I have seen Biden’s efforts. I agree the emphasis on battery-powered electric cars is silly because, as I blogged previously, not only are the extractives industries very polluting in nature, but at present there are insufficient reserves. We cannot meet the target. Besides putting money into research from thermonuclear fusion, I think more effort should be put into molten salt fission power, of the sort that burns its own nasties. I also think more money should be put into biofuels research (admittedly I am biased here, but much of the fuel can be made from stuff that otherwise simply rots and puts methane into the atmosphere) because (a) we have heritage vehicles, (b) hydrocarbons are still the best way to power aircraft, (c) We still have to power ships, and (d) there are many projects in more remote regions where diesel motors are preferable to anything else through the ease of refuelling.

      • Indeed. The (enormous) natural gas infrastructure can be easily adapted to 20% hydrogen (no modifications necessary). Beyond this, only small modifications. The hydrogen could be produced by renewable means. That would enable to co-opt the existing fossil fuel infrastructure. That’s what Biden should be doing. Instead he is throwing a bone to financial speculators by financing electric cars (which cost twice the CO2 to make relative to ICE). As it is California runs on 2% sun-wind renewables.

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