Why is Plastic Non-biodegradable?

Most plastic is manufactured from petroleum the end product of a few million years of natural decay of once-living organisms. Petroleum’s main components come from lipids that were first assembled long ago in those organisms’ cells. So the question is, if petroleum-derived plastic comes from biomaterial, why doesn’t it biodegrade?

A crucial manufacturing step turns petroleum into a material unrecognized by the organisms that normally break organic matter down.

Most plastics are derived from propylene, a simple chemical component of petroleum. When heated up in the presence of a catalyst, individual chemical units monomers of propylene link together by forming extremely strong carbon-carbon bonds with each other. This results in polymers long chains of monomers called polypropylene.

“Nature doesn’t make things like that,” said Kenneth Peters, an organic geochemist at Stanford University, “so organisms have never seen that before.”

The organisms that decompose organic matter the ones that start turning your apple brown the instant you cut it open “have evolved over billions of years to attack certain types of bonds that are common in nature,” Peters told Life’s Little Mysteries.

“For example, they can very quickly break down polysaccharides to get sugar. They can chew up wood. But they see a polypropylene with all its carbon-carbon bonds, and they don’t normally break something like that down so there aren’t metabolic pathways to do it,” he said.

But if all you have to do to make propylene subunits turn into polypropylene is heat them up, why doesn’t nature ever build polypropylene molecules?

According to Peters, it’s because the carbon-carbon bonds in polypropylene require too much energy to make, so nature chooses other alternatives for holding together large molecules. “It’s easier for organisms to synthesize peptide bonds than carbon-carbon bonds,” he said. Peptide bonds, which link carbon to nitrogen, are found in proteins and many other organic molecules.

Environmentalists might wonder why plastic manufacturers don’t use peptide bonds to build polymers rather than carbon-carbon bonds, so that they’ll biodegrade rather than lasting forever in a landfill . Unfortunately, while peptide bonds would produce plastics that biodegrade, they would also have a very short shelf life. “It’s an issue of ‘you can’t have your cake and eat it too,'” said Jim Coleman, chief scientist at the US Geological Survey Energy Resources Program. “When you buy a plastic jar of mayonnaise, you want [the jar] to last a few months.” You don’t want it to start decomposing before you’ve finished the mayo inside.

For the original article visit livescience.com!

[Photo Credit: Antonio Oquias | Dreamstime]

Aclima

Until now. Beginning in 2015, a pair of Google Street View cars, equipped with high tech “mobile labs” developed by San Francisco–based startup Aclima, crisscrossed the streets of West Oakland taking second-by-second samples of the area’s air. They tested for nitrogen dioxide and a type of pollution known as black carbon (bad for your heart and lungs, not to mention the planet), as well as nitric oxide. The cars hit every stretch of pavement, from tiny cul-de-sacs to truck-choked Peralta Street, multiple times, taking millions of measurements.

There are three stationary air pollution monitors for all of Oakland, which reveal the city’s air quality as a whole. But the Street View cars can tell you what the air is like at, say, the corner of Market Street and Grand Avenue—basically anywhere you can drive a Street View car. They can even tell you how the air varies from one end of a single block to the other for a truly hi-res view of the problem.The result: one of the largest and most granular data sets of urban air pollution ever assembled in the world.

Quoting Google’s interview on Aclima: “We visited each block on between 20 and 50 different days over the course of a year,” says Joshua Apte, an engineering professor at the University of Texas at Austin. In the process, they were able to identify patterns they wouldn’t have otherwise seen. “If pollution spikes for an instant, it may or may not be such a bad thing. But if pollution is consistently high, that’s something we really should care about.”

Imagine what difference awareness on air pollution can make when this information becomes more accessible!

Visit https://aclima.io/ for more information!

Marine Debris Resources

 

Marine Debris office of Response and Restoration has great resources on learning about debris!

Here is a list of some frequently asked questions (and links to answers):

Visit their website for more educational resources!