[Metalab] led throwies

[Bernhard Kuemel]

On 11/22/2010 01:34 PM, Damian Stewart wrote:

> erm. just be aware that led throwies are a bit of an environmental
> disaster. try and make it so you clean up properly after you're done.
> batteries in the groundwater == very very bad for the environment.

This depends a lot on cell chemistry.

Lithium cells are typically lithium - manganese dioxide, which I'd both
consider harmless. Well, Lithium and it's followup compounds are
caustic, but once diluted or neutralized I'd have no problem drinking
them. Lithium is even used as medicine.

The electrolyte is a lithium salt dissolved in a mixtiure of organic
solvents, e.g. Lithium perchlorate in propylene carbonate and
dimethoxyethane (DME).

Lithium perchlorate doesn't seem to be a big problem in the case of a
few lithium cells dumped in the soil.

Propylene carbonate is irritating and is replacing the environmentally
more harmful cresols.

Dimethoxyethane is miscible with water toxic and can impair
reproductivity and cause birth defects.

http://www.jtbaker.com/msds/englishhtml/d5712.htm says: Do not flush to
sewer! US Regulations (CERCLA) require reporting spills and releases to
soil, water and air in excess of reportable quantities.

Degradation products may be more harmful.

It is not, however, flagged as 'harmful for the environment'. I don't
know how it is degraded. It can form peroxides with oxygen.

So, while a few typcial lithium cells may not be a long term hazard it
is still a good idea to avoid their release to the environment.

They are certainly less harmful than cells which contain the toxic heavy
metal element mercury (these are quite rare these days, IMO) and
recharchable NiCd cells which contain the toxic heavy metal element
cadmium. Chemical elements can not be degraded (except with nuclear
reactions).

Bernhard