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File: 970107_sep96_decls17_0006.txt
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
s t tie C@)14TAr-T of In tt@e case at h(,@a).tt,
i.s del'i.n@.1
agei,it. 'I'me magft3tttde at expc%eltre-
ts by measuring or ez'ritpating the amc.@Ltrit of an age-tit availat)l*@- ror
at the gut, or skin, riot 'the kmcmti,it absorbed.
l@, -liffe@rerit met@ds are use(i to calculate exposure. Average Daily CipovtsrF.-
(AI)E) IS all average -zxposLfre compttterl for tlie pt+.i,iod over which exposure
c)cci.trs, and is used to calculate risP.-.s for nort-cancer toxic effects. Lifetime
Ave-i-aqe Daily Exposure (LADE), used to calct.tlate carcinogenic r,isl,.,.s. 1nto
,@CCOLtnt the fact that while carcinogenic hazard values @ir-o determined with an
asgt.imptioii of lifetime exposure, 4CttiAl eXI:PO$Llre may be over a shorter petiod.
ADE an (Contaminant Concentration x Contact Rate) / Body wei4l)t
LALIE - ADE Y (Exposure Period in Years / Lifetime)
'ontact Rate is the kmostnt of the contaminated ovediLtM (water, air, food) with
which a per-son comes into contact (generally a daily a@eragta) for the period of
,-xpost.tre (,u.q. @iters per day of water ingested, kilograms per day of food
ingested, cubic meters per da- of air inhaled).' Both ADE and LADE are
generally expressed in units of milligrams of the contaminant available for
'Absorption$ per Pilogeam of body weight, per day.
The risp value% calculated by RISK*ASSISTANT reflect both the uncertainties
associated with the estimation of toxic hazard information for each chemical
and the uncertainties associated with the exposure estimates you have
calculated. To understand the influence Of the quantitative exposure
@estimates on the corresponding calculations of risk$ it is necessary to
consider the key assumptions used In deriving them, and the uncertainties
A key assumption is that the contentritioht specified -for various
environmental media represent the true concentrations to which people
will be exposed during the period a-? exposure. Actual contaminant
concentrations will likely vary across both time and space.
The selection of exposure scenarios will also hay* a significant
influence on predicted exposures. Actual exposures to members of any
specified population will vary in accordance with the degree to which
they participate in the activities described by the exposure scenarios.
Similarly,, the numerical parameter values applied to each exposure
scenario will have a marked effect an exposure. The default values
provided are estimates for the entire U.S. population. Various
demographic factors (including 4e*graphic regions rural or urban setting,
socioeconomic status and ethnic heritage) may call for significant
alterations In these values.
'The uncertainty analyses provided as an option by RISK*ASSISTANT can
illustrate the differences between the risk, estimates that you have calculated
and risks calculated using alternative assumptions.
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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