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Humbolt

Polyvinyl alcohol biograding and impacts on waterways

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Recently Ive had discussions with a dishwasher tablet company ( Natures Organics who market themselves as environmentally prudent) and was hoping someone with a grasp on the chemistry could advise me before i reply.

They individually wrap each tablet with polyvinyl alcohol which they claim is " a type of polymer that is fully water soluble; the component ingredients then being fully biodegradable".  I left a wrapper in a glass for a week and noticed no further degradation beyond a silicone coloured liquid suspended in water.  So i wondered how do naturally occuring enzymes finish the job?  Under what circumstances are they present, ie is the packaging likely to come into contact with these enzymes during its journey.

 

Came across comments from a polymer chemist who says PVA "is water soluable but not sure of the effects on marine life or water based ecological systems" He goes on to suggest there is an issue with "degradation of the aliphatic polymer backbone.  No naturally occuring enzymes or bacteria are currently known to be able to degrade this structure".

 

The company claims its 'Earth choice' tabs are individually wrapped because 'they can cause irritation in some people'.

 

Kindness

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Posted (edited)

Have you tried heating it at all to see if it degrades/falls apart? sometimes warmer water (energy) can speed up the process of things breaking down. 

 

Meanwhile if it does require heat to break down (which it looks like it does from googling it) its sort of rendering their claim for it to be environmentally friendly false, as once it enters the ocean it'd have to travel to hawaii to get above 25°c lol

 

I reckon there would be a variety of different types which probably dissolve at various temperatures, for the dishwasher tablet it would probably make sense they'd have it at a higher temperature. 

Edited by Caster
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16 hours ago, Humbolt said:

Recently Ive had discussions with a dishwasher tablet company ( Natures Organics who market themselves as environmentally prudent) and was hoping someone with a grasp on the chemistry could advise me before i reply.

They individually wrap each tablet with polyvinyl alcohol which they claim is " a type of polymer that is fully water soluble; the component ingredients then being fully biodegradable".  I left a wrapper in a glass for a week and noticed no further degradation beyond a silicone coloured liquid suspended in water.  So i wondered how do naturally occuring enzymes finish the job?  Under what circumstances are they present, ie is the packaging likely to come into contact with these enzymes during its journey.

 

Came across comments from a polymer chemist who says PVA "is water soluable but not sure of the effects on marine life or water based ecological systems" He goes on to suggest there is an issue with "degradation of the aliphatic polymer backbone.  No naturally occuring enzymes or bacteria are currently known to be able to degrade this structure".

 

The company claims its 'Earth choice' tabs are individually wrapped because 'they can cause irritation in some people'.

 

 

 

That's depressing, but an excellent point. I switched to individually wrapped dishwashing tabs in my lab dishwasher cos the unwrapped ones would physically degrade over time, but I'm also aware of any potential impact ( less likely on the actual glassware cos after washing it's rinsed twice before drying ) of both detergent and packaging.

 

All a manufacturer has to do is show best practice for the recognised and available technologies under legislation. Whether the govt or industry should monitor all degradation products/impact is a non-issue, because they're simply not going to for every product til it crops up in the news. It's finally up to consumers to trust that standards are continuous, transparent and honest

 

Look, seriously the only way to work this stuff out is to do it ourselves. And even then the best experiment design won't replicate the infinitely complex soil and other environmental co-factors. There's not only bacteria, and enzymes, but also microfauna, fungi, slime moulds and things we probably haven't discovered and can't consider as cofactors yet

 

If you're passionate about this and related issues it'd be worthwhile to consider degradation products, and set up a working protocol to analyse and share results

 

A basic ( ie facile, simple, thorough but somewhat incomplete ) experiment design would be trivial, funds for a thorough chemical/ microbial analysis of each sample could be more of an issue, but the biggest issue is the logging over time, the synchronisation of standards so that others could repeat the experiment, data integrity, centralisation and multiply redundant ( ie backed up safely ) storage  and finally publicising results so they can be understood and critiqued by a wider audience

 

It's also a possible backbone plan for a Roundup ( glyphosate ) experiment

 

Citizen science. It's something everyone can do. And it means you really give a fuck, not just an FB like

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Dunno the chemistry of this one in a wastewater stream. 

 

There is probably assumptions that the wastewater stream leads to a treatment plant.... Not all plants are equal... It'll behave differently in absorption trenches (or any on-site ww)  if your out the sticks as the microbes will be different,and lacking some processes. 

 

The "assumption"  would be certain bacteria(primarily)  in the ww plant break it down... Lol... Theory and practice are two different things though. 

 

If the wttp is treating to a lower standard (common....) or bypassed due to exceeding what it can handle  ( ie spill shit water out into the environment after rainwater infiltration ...)  then I wouldn't expect as rapid degradation out in the wild. 

 

Residency time is a big issue in ww management, even when processes are available... They may not stay in it long enough for treatment if undersized or overloaded. 

 

Tassies ww treatment is fckn pathetic BTW.... Dilution is still the solution to pollution...With a bit of latent wild biodegration of some products. 

 

Jaded Fck stops now :wink:

 

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On 08/06/2019 at 7:20 PM, waterboy 2.0 said:

Dunno the chemistry of this one in a wastewater stream.

 

Brilliant response, thank you!

 

I got caught up with soil chem possibles and didn't answer the question proper

 

Great to hear from an expert

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