DSHW-2006-006053 - 0901a06880158838

RECEIVED
OCT 11 20n6
SOLID & HAZARDOUS WASTE
Human-Health Risk-Based Concentration Goals for
WellTCC3A
ATK Launch Systems, Promontory Facility
June 2006
w,
rs
June 6, 2006
Paul Hancock
Manager, Environmental Remediation
ATK Thiokol Inc.
Promontory Facility
P.O. Box 707
Brigham City, UT 84302-0707
Subject: Human-Health Risk-Based Concentration Goals for Well TCC3A
Dear Paul:
Pursuant to your request, I have evaluated the human-health risks of perchlorate and
trichloroethylene ("TCE") in water obtained from Well TCC3 A at your Promontory facility.
Data collected from this well since March 1989 have indicated the following concentrations of
these constituents:
EarthFax
EarthFax
Engineering, Inc.
Engineers/Scientists
7324 So. Union Park Ave.
Suite 100
Midvale, Utah 84047
Telephone [phone]
Fax [phone]
www. eaithlax. com
Date
March 1989
September 1992
October 1992
December 1993
February 1996
May 1996
May 2001
October 2002
November 2005
Note: NS = not samplee
Perchlorate
(ug/L)
NS
NS
NS
NS
NS
NS
36
38
42.7
Trichloroethylene
(ug/L)
ND
0.85
ND
1.2
1.9
2.8
7.2
8.7
10.7
ND = not detected at method detection limit
It is my understanding that this water is used in the Plant 3 area for process purposes as well as
showering, hand washing, and as an emergency eye wash supply. It is ftirther my understanding
that access points to the water are labeled to indicate that it is not to be ingested.
Risk-based concentrations of perchlorate and TCE that are considered protective of human health
under the showering and hand washing scenario were calculated using the following equation:
C = TRxBWxAT
TVxCFxSAxKxETxEFxED
Paul Hancock
June 6, 2006
Page 2
where C =
TR =
BW-
AT =
TV =
CF =
SA =
Kp =
ET =
EF =
ED =
SF =
RfD =
remediation goal at the specified risk level (mg/L)
target risk level (dimensionless; TR - 10"^ excess individual lifetime cancer risk
or a hazard index of 1.0 for noncancer risks)
adult body weight (kg)
averaging time (days) = 70 yr x 365 days/yr for carcinogens
= ED X 365 days/yr for noncarcinogens
absorbed toxicity value = SF (for carcinogens)
= 1/RfD for noncarcinogens
units conversion factor (10 L/cm-m^)
adult skin surface area (m^)
chemical permeability constant (cm/hr)
exposure time (hr/day)
exposure frequency (day/yr)
exposure duration (yr)
oral cancer slope factor (mg/kg-day)"'
oral reference dose (mg/kg-day)
The showering scenario was considered more conservative than hand washing since it involves
contact with more skin area for a longer period of time. Thus, the hand washing scenario was
not considered further. Exposure during showering may come in the form of dermal contact with
the water and inhalation of volatiles released from the water. The following exposure factors
were assumed for the dermal contact pathway under the showering scenario (see U.S.
Environmental Protection Agiency, 2004):
Adult skin surface area (SA) = 1.8 m^
Reasonable maximum exposure time (ET) = 0.58 hr/day
Exposure frequency (EF) = 250 days/yr
Exposure duration (ED) = 25 yr
Based on these factors and appropriate reference doses and cancer slope factors, risk-based
concentrations under a showering scenario were calculated as 6,900 ug/L for perchlorate and 210
ug/L for TCE (see Attachment A).
Perchlorate is not volatile and, therefore, presents no inhalation risk during showering. The
concentration of TCE that is considered protective of human health due to inhalation under the
showering scenario was calculated using the following equation:
C = TRxBWxAT
TVxKxIRxEFxED
Paul Hancock
June 6, 2006
Page 3
where C =
TR =
BW =
AT =
remediation goal at the specified risk level (mg/L)
target risk level (dimensionless; TR = 10"*^ excess individual lifetime cancer risk
or a hazard index of 1.0 for noncancer risks)
adult body weight (kg)
averaging time (days) = 70 yr x 365 days/yr for carcinogens
= ED X 365 days/yr for noncarcinogens
TV = absorbed toxicity value = SF (for carcinogens)
= l/RfD for noncarcinogens
K = volatilization factor (0.5 L/m^ - see Andelman [1990])
IR = , inhalation rate (m^'/day)
EF = exposure frequency (day/yr)
ED = exposure duration (yr)
SF = inhalation cancer slope factor (mg/kg-day)''
RfD = inhalation reference dose (mg/kg-day)
Since workers will be exposed to volatiles in the shower water only during the time of
showering, the conservative inhalation rate of 20 m^/ day (U.S. Environmental Protection
Agency, I99I) was reduced based on the ratio of 0.58/8.0 (i.e., the hours per day exposed to
shower water vs. the hours per day on the job). This resulted in an inhalation rate during
showering of 1.5 m"'/day. As recommended by the U.S. Environmental Protection Agency
(2004), the exposure frequency (EF) was assumed to be 250 days/year and the exposure duration
(ED) was assumed to be 25 years, as noted above.
Based on these factors and appropriate reference doses and cancer slope factors, the critical risk-
based concentration for inhalation of TCE in shower water was calculated to be 64 ug/L (see
Attachment A). The combined risk due to dermal and inhalation exposure results in a risk-based
TCE concenfration for showering of 49 ug/L (see Attachment A). Hence, the critical human-
health risk-based concentrations at well TCC3A for perchlorate and TCE, under the showering
scenario, are:
Perchlorate: 6,900 ug/L
TCE: 49 ug/L
The current concentrations of perchlorate and TCE in well TCC3A are well below these levels.
Hence, these concentrations are considered protective of human health under the showering
scenario.
The potential risk associated with the eye wash scenario is extremely low. Given the rare
occurrence and short-term-duration of such a scenario, it is highly doubtful that the risk
associated with the eye wash scenario would exceed the risk associated with the much-more-
common showering scenario. Hence, concentrations of perchlorate and TCE that are protective
Paul Hancock
June 6, 2006
Page 4
of human health under the showering scenario are considered protective of human health under
the eye wash scenario. Nonetheless, it is my understanding that ATK is planning on installing
carbon vessels to treat the water used for domestic purposes in this area ofthe facility. This will
further reduce the potential risks associated with the eye wash scenario.
I have appreciated the opportunity to provide this information. Please contact me ifyou have
any questions.
Sincerely,
Richard B. White, P.E.
President
References Cited
Andleman, J.B. 1990. Total Expostire to Volatile Organic Compounds in Potable Water. In
K.P. Cantor, R.F. Christman, and M.M. Ram (eds.). Significance and Treatment of
Volatile Organic Compounds in Water Supplies. Lewis Publishers. Chelsea, Michigan.
U.S. Environmental Protection Agency. 1991. Risk Assessment Guidance for Superfund -
Volume I: Human Health Evaluation Manual (Supplemental Guidance: Standard Default
Exposure Factors), Interim Final. OSWER Directive 9285.6-03. Office of Emergency
and Remedial Response. Washington, D.C.
U.S. Environmental Protection Agency. 2004. Risk Assessment Guidance for Superfund -
Volume I: Human Health Evaluation Manual (Part E, Supplemental Guidance for Dermal
Risk Assessment), Final. EPA/540/R/99/005. Office of Superfund Remediation and
Technology Innovation. Washington, D.C.
ATTACHMENT A
Risk-Based Concentration Calculations
PRGs FOR DERMAL PATHWAY
Source: WATER
Scenario: ?ShWering|l^i^^^^|il^^,a-».i
Site: rCromontbtylii^ell'^SAIwateB
Governing equations:
Cancer PRG:
Noncancer PRG:
where C =
TR =
HQ =
BW =
AT =
SFo =
RfDo =
CF =
SA =
Kp =
ET =
EF =
ED =
Assumptions:
Target risl< (TR) =
Target haz. quo. (HQ) =
Body weight (BW) =
Average lifetime =
Skin surface area (SA)
Exposure time (ET) =
Exposure freq. (EF) =
Exposure dur. (ED) =
PRG calculation:
C = (TR x BW X AT) / (SFo x CF x SA x Kp x ET x EF x ED)
C = (HQ X BW X AT X RfDo) / (CF x SA x Kp x ET x EF x ED)
Concentration resultsing in the specified risl< (mg/l)
Target cancer risk (unitless)
Target hazard quotient (unitless)
Body weight (kg)
Averaging time (days) = 70 yr x 365 for cancer risk, ED X 365 for noncancer risk
Oral cancer slope factor (mg/kg-day)-1
Oral chronic reference dose (mg/kg-day)
Units conversion factor (10 L/cm-m2)
Adult skin surface area (m2)
Chemical permeability constant (cm/hr)
Exposure time (hr/day)
Exposure frequency (days/yr)
Exposure duration (yr)
;;ii!ooEioo6i
mmmm
^m^m250]
Ref
kg
yr
m2
hr/day
days/yr
yr mm
Contaminant
RfDo
(mg/kg-d) Ref
SFo
(mg/kg-d)-1 Ref
Kp
(cm/hr) Ref
Noncancer PRG
(mg/l)
Cancer PRG
(mg/l)
Eerchjorateli^^iS^ a7^QgEiQ0^ mwi mm 6.9E+000 No SFo
WE^M wmmm>}om mm 4.9E+000 2.1E-001
-^n Jft WM
ip
m
mmmm •mmmm m^ ^m
References:
1. RAGS Part A, EPA 1989 (EPA/540/1-89/002)
2. RAGS Part E, EPA 2004 (EPA/540/R/99/005) -
3. National Research Council, "Health Implications of Perchlorate Ingestion", 2005
4. Withdrawn value requested by UDSHW in a letter to ATK dated 1 Nov 2005
5. IRIS
6. EPA provisional value
PRGs FOR INHALATION PATHWAY
Source: WATER
Scenario: i^^^^^^^^^^Mmm^
Site: ^IromoSq'^Jl.VVellfSiflKw^^
Governing equations:
Cancer PRG:
Noncancer PRG:
where C =
TR =
HQ =
BW =
AT =
SFi =
RfDi =
VF =
IR =
EF =
ED =
Assumptions:
Target risk (TR) =
Target haz. quo. (HQ) •
Body weight (BW) =
Average lifetime =
Inhalation rate (IR) =
Volatil. Factor (VF) =
Exposure freq. (EF) =
Exposure dur. (ED) =
PRG calculation:
C = (TR x BW X AT) / (SFi x VF x IR x EF x ED)
C = (HQ X RfDi x BW X AT) / (VF x IR x EF x ED)
Concentration resulting in the specified risk (mg/l)
Target cancer risk (unitless)
Target hazard quotient (unitless)
Body weight (kg)
Averaging time (days) = 70 yr x 365 for cancer risk, ED X 365 for noncancer risk
Inhalation cancer slope factor (mg/kg-day)-1
Inhalation chronic reference dose (mg/kg-day)
Volatilization factor for water (L/m3)
Inhalation rate (m3/day)
Exposure frequency (days/yr)
Exposure duration (yr)
^HpQEyjflfil
'MiM^Wj
s^lS^7Qj
m^mm i^mkwj ^^=^0153
^*i^2505
mmm25i
Ref
kg
yr
m3/day
L/m3
days/yr
yr
mm.
m{
IsH
Contaminant
RfDi
(mg/kg-d) Ref
SFi
(mg/kg-d)-1 Ref
mM
Noncancer PRG
(mg/l)
Cancer PRG
(mg/l)
-TirLchLQ.rQg.thylepel mm^EiOOl^. ^!6100^0P3| 1.6E+000 6.4E-002
^
References:
1. RAGS Part A, EPA 1989 (EPA/540/1-89/002)
2. Modified for time of exposure to shower water
3. RAGS Part B, EPA 1991 (OSWER 9285J-01B)
4. Provisional value (EPA/900-P-01-002A),'calculated from inhalation ref.conc.
5. Withdrawn value requested by UDSHW in a. letter to ATK dated 1 Nov 2005
Governing equations:
Combined PRG;
where C =
TR =
BW =
AT =
A, 8, C . .
Assumptions:
Target risk (TR) =
Target haz. quo. (HQ) ••
Body weight (BW) =
Average lifetime =
Exp. duration (ED) =
C = (TR X BW X AT) / (A + B + C + . . .)
Concentration resultsing in the specified risk (mg/l)
Target toxicity value (1 OE-06 for cancer risk, HQ=1 for noncancer risk)
Body weight (kg)
Averaging time (days) = 70 yr x 365 for cancer risk, ED X 365 for noncancer risk
Toxicity and exposure factors calculated for individual pathways
fel5flQE^6|
kg
yr
yr
Combined PRG Calculation (Noncancer):
Contaminant
Berohlo^a
m ja-sm^mi
Individual PRG by Pathway (mg/l)
Dermal inhalation
Combined
Pathway PRG
(mg/l)
1.2E+000
6.9E+000
No RfD
No RfD
No RfD
No RfD
No RfD
No RfD
No RfD
No RfD
Combined PRG Calculation (Cancer):
Contaminant
Individual PRG by Pathway (mg/l)
Dermal Inhalation
Combined
Pathway PRG
(mg/l)
^TriiijfilbTdetl g2:a.0E5.Qi11 ?6a.0EgQ02l 4.9E-002
iRIe'rciilbrate' NoSF
NoSF
NoSF
NoSF
mm NoSF
NoSF
I^MM NoSF
NoSF
NoSF