Xref: utzoo can.general:1013 sci.bio:1602 sci.med:7789 sci.misc:2818
Path: utzoo!yunexus!geac!sq!lsuc!ncrcan!ontenv!soley
From: soley@ontenv.UUCP (Norman S. Soley)
Newsgroups: can.general,sci.bio,sci.med,sci.misc
Subject: Re: Dioxin and Native Communities
Message-ID: <276@ontenv.UUCP>
Date: 15 Nov 88 05:17:03 GMT
Article-I.D.: ontenv.276
References: <544@yunccn.UUCP> <591@apss.apss.ab.ca>
Organization: Ontario Ministry of the Environment, Toronto
Lines: 44

In article <591@apss.apss.ab.ca>, nmm@apss.ab.ca (Neil McCulloch) writes:
> In article <544@yunccn.UUCP>, john@yunccn.UUCP (John Hummel) writes:
> > 1)"Tests have revealed 210 parts per trillion of 2,3,7,8-TCDD, the most
> > 
> > 1 to 9 parts per trillion." (MOE Press Release July 17,1986)
> > 
> > ces.No 2,3,7,8-TCDD was found at a detection level of 20 parts per quadrillion
> 
> Would someone with experience of testing for trace chemicals care to 
> comment on these levels? 20 parts per quadrillion! Now that's 20 parts in
> 1,000,000,000,000,000. I find it hard to believe that reliable measurements
> can be made at this level from samples taken in the field.

I am not speaking from the position of authority you seek, and
although I work for the organization which published (and holds the
copyrights on ;->) the documents from which the figures were drawn 
I for darn sure don't speak for them now.

Misinterpretation of scientific reports is common on the part of the
media, for instance contrary to what the newspaper tells them some
people who test positive for HIV antibodies are refusing to actally
contract AIDS. The problem being that one of the original reports on
AIDS contained some statistics which were grossly misinterpreted by
the press to mean that HIV exposure leads irreversably to AIDS then
death.

The quoted figures are all drawn from press releases written
by, yes you got it, former reporters. If one were to go back to the
original scientific reports a clearer picture might emerge. In this
case I gather that what was being reported on are the results of a
"exists/does not exist" test which is believed to have a threshold in
the order of the figure quoted. Considering some of the things that
medical science is able to detect in a complex fluid like human blood
it shouldn't be too hard to spot traces of something as complex as 2,3,7,8-TCDD
in a simple fluid like water (as cluttered as a field smaple might be
it's got nothing on what we cart around in our bloodstream) also
considering just how dangerous that little guy is (makes PCB's look
like drinking water) I certianly hope the detection threshold is very
low.
-- 
Norman Soley - Data Communications Analyst - Ontario Ministry of the Environment
UUCP:	uunet!attcan!lsuc!ncrcan!ontenv!soley	VOICE:	+1 416 323 2623
OR:     soley@ontenv.UUCP 
  " Stay smart, go cool, be happy, it's the only way to get what you want"