Archived posting to the Leica Users Group, 2000/09/11

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: Re: [Leica] Mercury (Hg) Batteries and Minamata
From: John Coan <>
Date: Mon, 11 Sep 2000 16:15:52 -0400
References: <>

Do you happen to know what mercury compound is in fluorescent tubes?  I
wonder how much is in one industrial size light, vs. one PX-625? 
Anybody else?

William Gower wrote:
> With regards to the recent postings on Hg, batteries and Minamata:
> > From: "Raimo Korhonen" <>
> > Metallic mercury is not particularly harmful - but some organic compounds
> > that contain mercury are lethal and thatīs what caused Minamata, not
> > mercury batteries.
> Partly true: Metallic (elemental Hg) is not "harmless" per se, but the rate
> of absorption into the bloodstream via the skin slow. Slow enough, that you
> would have to be in direct contact for long periods  of time for any
> significant symptoms to manifest themselves. Not that it wouldn't or
> couldn't happen, mind you - it's just that the likelihood is small.
> Remember handling the stuff as a kid when you broke a thermometer or old
> thermostat ? How about good old dental fillings (amalgams of Mercury and
> Tin). Although I wouldn't recommend it, accidental swallowing some Hg is
> generally considered harmless (save for a tummy ache).
> My point - exposure by handling or occasional ingestion of elemental Hg (the
> good old silver liquid) is, for all intensive purposes, benign. The skin is
> a pretty good barrier to uptake of Hg.
> However, increase the rate of absorption of Hg into the bloodstream, and
> trouble begins.
> How to you increase the absorption ? Via the respiratory tract is one.
> Exposure to Hg dust (mining of sulphide ores rich in cinnabar) or vapour
> (heating Hg in the presence of oxygen, forming HgO) are the two most common
> and toxic occupational exposure routes.
> Dimethyl Mercury (CH3)2Hg is the real bugger in the environment. This is an
> organic mercury compound that is readily absorbed into the bloodstream. In
> nature, certain aquatic organisms will break down elemental Mercury into
> this organic form. If the level of Mercury in natural waters is high, the
> concentration of of Dimethyl Mercury will be high as well. This translates
> into accumulation of Hg in marine life (i.e. fish).
> Minamata is a prime example. It was the high concentrations of Hg in the bay
> from industrial processes that caused an elevated level of Dimethyl Hg in
> the aquatic life. This, combined with a diet rich in seafood that caused the
> high incidence of Hg poisoning in the areas surrounding Minamata Bay, Japan.
> There have been other cases of widespread Hg poisoning due to eating
> contaminated grains that had been treated with organic Mercury pesticides. I
> believe it was in somewhere in the middle east (Iraq or ?)
> No, I'm no "expert", but I took enough toxicology and biochemistry courses
> to know that Hg is bad news. And yes, I have a Rollei 35s that needs to be
> recalibrated to the '625 alkaline cells.
> Kind regards
> William Gower

Replies: Reply from Amilcar de Oliveira <> (Re: [Leica] Mercury (Hg) Batteries and Minamata)
Reply from D Khong <> ([Leica] WTB: FOCOTAR 40/2.8)
In reply to: Message from "William Gower" <> ([Leica] Mercury (Hg) Batteries and Minamata)