[Dioxin-l] Re: Poor efficacy of residual chlorine in drinking water distr...

[Jon Campbell]

David,

    You were not around last year when it was reported (I believe by Charlie
Cray) that a number of midwestern U.S. communities had lost their entire
water supplies when it was discovered that vinyl chloride monomer was
leaching from their water supply pipes. It is also fairly well accepted
today that the vinyl chloride monomer found in most municipal dump effuent
and contaminated groundwater is due to leaching of VCM from PVC and/or
breakdown of PVC into VCM. Your knowledge of the theory of plastics does not
seem to bear itself out in practice.

Regards
Jon Campbell
-----Original Message-----
From: david bell [mailto:burnt_paper@hotmail.com]
Sent: Sunday, January 09, 2000 6:33 PM
To: Evertcc@aol.com
Cc: dioxin-l@lists.essential.org
Subject: Re: [Dioxin-l] Re: Poor efficacy of residual chlorine in
drinking water distr...


Hi Carl
>Connie,
>
>I would be more interested in knowing about any contamination from the PVC
>pipe now used in many water systems than of the chlorination of the water
>itself.

PVC is long-chain, and essentially insoluble in water. Hence it has no 
toxicity. Vinyl chloride monomer is a good human carcinogen, but there is 
very little of it in PVC, it gets diluted out a lot, and you can detect the 
resulting cancer very easily. VCM gives cholangiocarcinoma in humans, and I 
am not aware in any variation in the rate of this rare human cancer.

>My other concern is the combination of chlorine and organic compounds to 
>form
>triholomethane for example. I don't think that we can just look at free
>chlorine by itself.

I guess you are probably aware that there is a massive ongoing debate around

this issue. Some people argue that the (potential) cancer risk from tiny 
quantities of chloromethanes are significant. Others, that the public health

benefits of chlorination vastly outweigh any cancer risk. There is a 
well-founded argument that the carcinogenicity of trichloromethane has a no 
effect level- and that the low levels in water are without significance.

cheers
david

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