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

[pat.costner@dialb.greenpeace.org]

Dear Mr. Bell,

I posted the abstract of the study by Payment (1999).  
Subsequently, I pointed out how your interpretation of the abstract 
differed, in very important and fundamental ways, from the wording 
of the abstract itself.  I.e., you misread and/or misinterpreted the 
abstract.  Also, your last question below suggests that continuing to 
pursue this discussion will not be productive.  Comprehension is a 
matter of attention and practice; it is rarely directly imparted.  

My kind regards,

Pat Costner

On 11 Jan 00, at 19:00, david bell wrote:
Re: [Dioxin-l] Re: Poor efficacy of residual chlo

> Hi Pat
> perhaps you can explain the wording of the abstract to me: I have not seen
> the paper, and do not know what information it contains.
> 
> >microorganisms remained relatively
> >     unaffected in water from the distribution systems tested
> 
> I understand this-
> 
> >except for Escherichia coli
> 
> Can you please explain to me what this means ? Does this not mean that E
> coli is affected by water from the distribution systems tested ? Is this
> not the wording of the abstract ?
> 
> If E coli is disinfected, is this not a good thing ?
> 
> If other bacteria and viruses are not inactivated, that is clearly a 'bad
> thing'; but you don't make the 'bad thing' better by adding another
> pathogen, E coli, to the mix.
> 
> david
> 
> >Dear Mr. Bell,
> >
> >I urge you to give the abstract of the study by Payment (1999)  a
> >more careful reading.  You have interpreted it to say that "E coli is
> >inactivated by residual chlorine throughout the distribution system." 
> >This differs considerably from the actual wording of the abstract, as
> >follows:
> >
> >     "Except for Escherichia coli, microorganisms remained relatively
> >     unaffected in water from the distribution systems tested. When
> >     sewage was added to the water samples, indigenous thermotolerant
> >     coliforms were inactivated only when water was obtained from sites
> >     very close to the treatment plant and containing a high residual
> >     chlorine concentration."
> >
> >You then note, " Given that E coli is a principal contaminant of
> >sewage (and in turn the water supply system), and can be highly
> >pathogenic (eg E coli 0157), this abstract can easily be used to
> >  make a case for chlorination of water supplies."   With this, I
> >  would suggest that you have missed a major finding of the study:
> >
> >     "Clostridium perfringens was barely inactivated, suggesting that the
> >     most resistant pathogens such as Giardia lamblia, Cryptosporidium
> >     parvum, and human enteric viruses would not
> >    be inactivated. "
> <snip>
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Pat Costner
Greenpeace
P.O. Box 548
 or 512 County Road 2663
Eureka Springs, Arkansas 72632
ph: 1 501 253 8440
fx: 1 501 253 5540
em: pat.costner@dialb.greenpeace.org
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