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DaVinci, respirometry and a sip from a plastic water bottle …

A few weeks ago, an article mentioned that if Leonardo DaVinci drank from a plastic water bottle and then set it on a counter, that bottle would still be intact today. Of course, I can’t remember, nor could find, the source.

It’s a metaphor nonetheless on the outsized lifespan of plastic and its hyper-proportional impact on the environment.

Simply put, plastic in its many forms does not go away quickly or easily. In fact, it never truly biodegrades or vanishes – nothing in nature is predisposed to consume it.

Still, no one really knows for certain how long plastics and polystyrenes (Styrofoam) stick around. It’s a mixture of scientific finding and estimation – along with some conjecture.

Much of that educated guesswork is based on respirometry tests. Intended to plot the biodegradation of materials in wastewater treatment, the process is among several also put to use to gauge the potential biodegradation rates of non-organics; i.e. plastics.

Plastics are virtually impervious to the environmental influences that degrade organic matter; air, water and sun. For example, when scientists test generic plastic bags, nothing happens – there’s no CO2 production and no decomposition. Why? The most common type of plastic shopping bag – the kind you get at supermarkets – is made of polyethalene, a man-made polymer that microorganisms don’t recognize as food.



If this plastic water bottle remained in place, the sun would eventually deteriorate it yet the plastic particulates would never really leave our environment.

Yet while standard polyethylene bags don’t biodegrade, they do photodegrade. When exposed to ultraviolet radiation from sunlight, polyethylene’s polymer chains become brittle and start to crack. But even in degraded form, plastic remains with us even in microscopic form. There are insideous environmental impacts: when tiny organisms ingest small plastic particulates, those organisms in turn are eaten by larger organisms – thereby introducing plastics into the bodies of larger animals.

This list is a composite list from several sources of the expected lifespan of various materials:

  • Aluminum can: 200-500 years
  • Disposable diapers: 550 years
  • Plastic bags : 20-1,000 years
  • Plasitic water bottle: 450 – 1,000 years
  • Plastic jug: 1 million years
  • Monfiliment fishing line: 650 years
  • Glass: 1-2 million years
  • Styrofoam: 1-plus million years

(Cited or paraphrased for this post:,,,

About Dave Bradley (264 Articles)
I was a writer by trade so one would think letters would come easily for me. It is so now, but wasn't always that way. Indeed, the first letter was written the Monday after Ellen started her freshman year in college. For years I've wondered - with no good answers - why I swiveled my office chair toward my computer screen to fire up a word processing document for that first letter. I just don't know. I just did. Perhaps it was the angst of separation or wanting to say things that had gone unsaid at that moment when we parted ways in front of her college dormitory. What was a one-off became habitual. When her brother Reid enrolled in the same college, his name was added to the salutation line. They were kids then and are adults now. No matter. The letter writing habit remains so today. I live in Brevard, North Carolina. I'm well away from where they live and don't see them nearly as often as I'd like. That's why letters, at least to me, fill the void of distance. The pages give me something to say and the space to say it. There is no assurance they read the letters; indeed, I have never asked if they do so. With the pace of their busy lives who could blame them for letting a letter sit unopened? Over time, it has dawned on me that the letters are both communicative - and cathartic. By nature, letters are about the writer; the writer can only write about their situation. Perhaps that is as it should be. It's all about the here and now from one person's perspective.

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