RE: [CPEO-MEF] natural attenuation -- the reality

[CPEO Moderator <cpeo@cpeo.org>]

><------ Original Message Follows ------>
>Date: Thu, 25 Nov 1999 02:55:22 EST
>From: RICHARD_McMURTRY@compuserve.com
>To: cpeo-military@igc.topica.com
>Subject: RE: [CPEO-MEF] natural attenuation -- the reality 
>
>-Original message from Richard McMurtry
>
>Andy assumes that action levels are protective of public health and the
>environment and that the widespread dispersal of low concentration
>carcinogens and endocrine disruptors below action levels is of no
>consequence.   Also, implied in his assertions is an assumption that  usi
>ng groundwater resources as a place to store and allow the low level
>spreading of carcinogens in areas where no drinking water wells exist or
>where no discharge to ecological areas exists is an appropriate use of the
>resource.
>
>Implied in this is the assumption that the process of developing action
>levels is scientifically sound or "is the best we can do with our existin
>g
>knowledge".
>
>This is one way of looking at this subject.
>
>Another way of looking begins with acknowledging that MCLs for drinking
>water are developed through a process that more resembles witchcraft (in
>the negative sense) than science.  That is to say, that public policy
>makers take the scientific evidence (e.g. cancer impacts at high dosage)
>and then extrapolate it beyond the point where they can verify their
>results through the scientific method of experimentation (that is they
>extrapolate high dosage cancer results into the realm of low dosage and
>probability calculations).  At that point, where they extrapolate it into
>
>unverifiable realms, it departs from science.  No one really knows the
>shape or the slope of the curve in these realms.  To call this science is
>
>to mislead the public and to practice self deception within the scientifi
>c community. 
>
>
>Also, even within the conventional methodology of cancer calculations the
>re is an acceptance of the fact that there is no safe level.  Some increase
> in cancer will result in a susceptible individual at a critical time with
>even exposure to one molecule.  The ambiquity is what the dose response
>curve looks like with increased dose above zero and what the curve looks
>like in response to exposure to mixtures of chemcials that humans are
>exposed to in the real world of pesticide-laden foods, benzene-laden air,
>tri-halomethane laden water and a host of other exposures.
>
>Another element of this alternative way of looking is to question whether
>
>the conventional way is indeed the "best we can do with our existing
>knowledge".   The questioning begins with acknowledgeing that we don't
>really understand what are the causes of many of the human and ecological
>
>health problems that plaque our society.    Admitting our ignorance allow
>s us to conclude that the risk-based numbers may be useful as a point of
>departure, as a bottom line to our action levels, but that a more
>responsible public policy in view of the uncertainties would be to
>determine how close to zero we can get with a reasonable incremental cost
>. 
>
>\
>
>With such an approach, one might conclude that even though there are no
>existing drinking water wells or ecological receptors impacted above acti
>on levels, that aggressive source control efforts (including remediation of
>contaminated soils) would be employed to reduce the mass of contaminants
>that would be allowed to disperse in the aquifer.  Perhaps also some pump
>
>and treat would be employed until the source control and high
>concentrations were reduced before natural attenuation would be employed
>
>This requires judgement to weight the benefits against the costs but this
>
>might be the "best we can do with existing knowledge", rather that deceiv
>e ourselves that action levels are protective.
>
>Richard McMurtry Silicon Valley Toxics Coalition
>
>
>
>
><------ End Of Original Message ------->


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