Health and Safety
Plastics degrade, albeit slowly, in all environmental settings by means of bio-degradation, photo-degradation, thermo-oxidative degradation or hydrolysis. Degradation is a chemical change that drastically reduces the average molecular weight of the polymer. Since the mechanical integrity of plastics invariably depends on their high average molecular-weight, any significant extent of degradation inevitably weakens the material. Weathering degradation of plastics results in their surface embrittlement and microcracking, yielding microparticles that continue on in the environment, known as 'microplastics.' Micro-plastics concentrate Persistent Organic Pollutants (POPs). The relevant distribution coefficients for common POPs are several orders of magnitude in favour of the plastic medium. Consequently, the micro-particles laden with high levels of POPs can be ingested by organisms in the bio-sphere. Given the increased levels of plastic pollution of the environment, this is an important concept in understanding the food web.
Read more about this topic: Polyvinyl Chloride
Famous quotes containing the words health and, health and/or safety:
“I am astonished at the singular pertinacity and endurance of our lives. The miracle is, that what is is, when it is so difficult, if not impossible, for anything else to be; that we walk on in our particular paths so far, before we fall on death and fate, merely because we must walk in some path; that every man can get a living, and so few can do anything more. So much only can I accomplish ere health and strength are gone, and yet this suffices.”
—Henry David Thoreau (1817–1862)
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—Anonymous Father. Ourselves and Our Children, by Boston Women’s Health Book Collective, ch. 5 (1978)
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