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Subject: CONCENTRATION CHEM ENVIRONMENTAL MEDIA COVERED IN ANALYSIS      

Unit: OTSG        

Parent Organization: HSC         

Box  ID: BX003205

Folder Title: EXPOSURE CALCULATIONS                                                                           

Document Number:          2

Folder Seq  #:         19






   Title tntc@o.- 4ite.-  J.n
                  -1                             kIR.E!;;). All values in IRI@@ have t)(,c..@ri
             .@id accepted 'for Aqency-.wi.dk...    I:,,, T@FIA. For chemicals not
    ro ZRRS, to),,i,city data were extracted from the fi@zaittv Effects Assesl-tllc@nt
            Tables (HEAST), (li%tr,:kbt.ited ctLiArtei,]Y by the Office (I               ar.(-
                                                                          f Etner,(Ierbcy
             Rez;m4-ise.  rhese v@iti.t.tes, and risk. estimates derived from          are


   @rir a @ry limited set of chemicals, carcinogenic slope factors and/or
   reference doses may be estimated from *upidemic)l(:)cjic data. collected in' mLiman--,.
   Most slope factors and RfDs, ltowc.?ver, are (jeri.ved from experimental studies in
   @ni m.*Is. St.1c.,Ii extrapolations Are based on the assumptions that 1) the
   ph-sioloqidal and biochemical responses of exposed persons will be               -
   qualitatively (but not necessarily quantitatively) the same as that seen in.the
   .Experimental animals, Z) effects seen at high doses in a limited number of
   animals over a comparatively brief period of observation are predictive Of
   @oxicit- at lower doses, it a sufficiently large group is exposed for a
                  long period. For some chemicals, hazard values may also have been
   extrapolated across differing routes of exposure.          This introduces additional
   uncertainty to these estimates.
   .The slope (potency) factors for cancer risks are estimated as the
   9.--th.percentile confidence limits using the linearized multistage model. As
   such, they are conservative, estimates at toxic hazard. Risks estimat4d,by
   combining these hazard values with exposure estimates are commonly referred to
   as upper-bound risksv but because exposure estimates may not represent upper-
   'bound estimate%, risk estimates are not true upper-bound risks.
his assessment
   refer ONLY to the specific exposure pathways enumerated in the astesimehtp and
Z,d*pend upon the specific exposure parameters used tar calculation. An exposure
   pathwae- combines contamination in an environmental medium, a scenario
   describing how a person contacts that medium, and a route of exposure (or I
   inhalation, or dermal). An assessment that incorporates other pathways ofa @c
   exposure, or that does not incorporate all of the pathways described in this
 ,analysis, will yield different exposure values. Further, exposure and risk
   TOTALS for each medium involve the assumption that the-same individual
   experiences ALL SCENARIOS corresponding to that medium.

   (3eoLtndwater

   Ingestion of  Drint-ing Water (Oral)
   This includes oral exposures from domestic water used for drinking or            cooking.

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Document 10 f:/Week-36/BX003205/EXPOSURE CALCULATIONS/concentration chem environmental media covered i:01029715471618
Control Fields 17
File Room = sep96_declassified
File Cabinet = Week-36
Box ID = BX003205
Unit = OTSG
Parent Organization = HSC
Folder Title = EXPOSURE CALCULATIONS
Folder Seq # = 19
Subject = CONCENTRATION CHEM ENVIRONMENTAL MEDIA COVERED I
Document Seq # = 2
Document Date =
Scan Date =
Queued for Declassification = 01-JAN-1980
Short Term Referral = 01-JAN-1980
Long Term Referral = 01-JAN-1980
Permanent Referral = 01-JAN-1980
Non-Health Related Document = 01-JAN-1980
Declassified = 02-JAN-1997