Groundwater Ingestion

A Carcinogenic COC B Non-carcinogenic COC

(1) Category I (1) Category I & II:

C = TR∗BW∗AT c∗365

SFo∗IRw∗EF∗ED∗AC = HQ∗RfDo∗BW∗AT n∗365

IRw∗EF∗ED∗A

(2) Category II (2) Category III:

C = TRII −III∗BW∗AT c∗365SFo∗IRw∗EF∗ED∗A C =

HQ∗RfDo∗BW∗AT n− III∗365IRw−III∗EF∗EDIII∗A

(3) Category III (3) Future groundwater ingestion

C = TR II− III∗BW∗AT c∗365

SFo∗IRw− III∗EF∗ED III∗A C = HQ∗RfDo∗BW∗AT n− III∗365

MLE

(4) Future groundwater ingestion

C = TRf∗BW∗AT c∗365

SFo∗MLE

Groundwater Protective Soil Concentration Saturated Soil Concentration

C = Ccategory∗100(β∗K d+θw+θa∗H ' )β

C = S∗(β∗Kd+θw+θa∗H ' )β

Health-Based Soil Concentration

A Resident Soil Ingestion and Inhalation

VFr = LS∗V∗DH

A HB∗√3.14∗α∗T

2∗Dei∗ϴ∗Kas∗CFu−1

where α = Dei∗θθ+ρs(1−θ)/ Kas

PEF = LS∗V∗DH∗3600

AHB∗CFu

0.036 (1−G )∗¿¿

(1) Carcinogenic COC (2) Non-carcinogenic COC

C =

TR∗BW∗AT c∗365

EF [ ( BW∗SFo∗CF w∗IFsoil . adj)+(SFi∗ED∗IRa∗( 1VF r

+ 1PEF ))] C=

HQ∗BW .C∗AT n .C∗365

ED. C∗EF∗[( 1RfDo

∗CFw∗IRsoil . C)+( 1RfDi

∗IRa∗( 1VF r

+ 1PEF ))]

For COC with SFo and RfC (no URF) toxicity values (e.g., dichlorobenzene 1, 4), use the following equations:

Soil ingestion: Ccarc = TR∗AT c∗365

SFo∗CFw∗EF∗IFsoil .adjSoil vapor inhalation: Cnc =

HQ∗BW . C∗AT n .C∗365

ED.C∗EF∗IRa

RfDi( 1VF r

+ 1PEF

)

Total Combined C = 1

1C carc

+ 1Cnc

=

11

TR∗AT c∗365SFo∗CFw∗EF∗IF soil .adj

+ 1HQ∗BW .C∗AT n .C∗365

ED .C∗EF∗IRa

RfD i( 1VFr

+ 1PEF

)

B Commercial/Industrial Worker

VFi = LS∗V∗DH

A HB∗√3.14∗α∗T C / I

2∗Dei∗ϴ∗Kas∗CFu−1

(refer to resident soil ingestion/inhalation for α)

PEF – refer to resident soil ingestion and inhalation

(1) Carcinogenic COC (2) Non-carcinogenic COC

C =TR∗BW∗AT c∗365

EDw∗EFw¿¿ C = HQ∗BW∗AT nw∗365

EDw∗EF w∗[CFw

RfDo∗IRsw+

IRa. w

RfD i∗( 1

VF i+ 1

PEF )]

For COC with SFo and RfC (no URF) toxicity values (e.g., dichlorobenzene 1,4), use the following equations:

Soil ingestion: Ccarc = TR∗BW∗AT c∗365

SFo∗CFw∗EFw∗EDw∗IRswSoil vapor inhalation: Cnc =

HQ∗BW∗AT nw .∗365EDw∗EFw∗IRa . w

RfDi( 1

VFi+ 1

PEF)

Total Combined C = 1

1C carc

+ 1Cnc

=

11

TR∗BW∗AT c∗365SFo∗CFw∗EFw∗ED w∗IRsw

+ 1HQ∗BW∗AT nw∗365

EDw∗EFw∗IRa .w

RfDi( 1VFi

+ 1PEF

)

Construction worker

A. Soil (ingestion and inhalation pathways)

VFconst =

L∗V exc∗DHAconst . soil

∗√3.14∗α∗T const

2∗Dei∗ϴ∗Kas∗CFu−1

(refer to health-based soil for α)

PEFconst = L∗V exc∗DH∗3600

A const .soil∗CFu

0.036 (1−G )∗¿¿ = 9*108

(1) Carcinogenic COC (2) Non-carcinogenic COC

C = TR∗BW∗AT c∗365EDconst . s∗EF const¿¿

C =

HQ∗BW∗ATn . const−s∗365

EDconst . s∗EFconst [CF w∗IRs

RfDo+( IRa . w

RfDi ( 1VF const

+ 1PEFconst ))]

For dichlorobenzene 1, 4 which has no URF, but RfC for the inhalation pathway, then

Soil ingestion: Ccarc = TR∗BW∗AT c∗365

SFo∗CFw∗EF const∗EDconst . s∗IRsSoil vapor inhalation: Cnc =

HQ∗BW∗ATn . const−s .∗365EDconst . s∗EF const∗IRa .w

RfD i( 1VF Const

+ 1PEFconst

)

Total Combined C = 1

1C carc

+ 1Cnc

=

11

TR∗BW∗AT c∗365SFo∗CFw∗EFconst∗EDconst . s∗IRs

+ 1HQ∗BW∗AT n.const −s∗365

EF const∗EDconst . s∗IRa .w

RfD i( 1VFConst

+ 1PEFconst

)

B Groundwater (inhalation and dermal contact pathways)NOTE: The number C (calculated in (1)-(3) below) shall be divided by Cavg (calculated in (4) below) to obtain the target number.

If tevent.const<t*, Z = 2Kp√6 τeventtevent . const

π; If tevet.const> t*, Z=Kp(

tevent . const

1+B+2 τ event

1+3B1+B

¿

(1) Carcinogens

C = TR∗BW∗AT c∗365

EFconst .∗EDconst .w∗(IRa . w∗K ws∗CF v∗SF i∗Aconst . water

L∗V exc∗DH+EV∗SAconst∗Z∗SFd∗CFwat

−1)

(2) Non-carcinogens

C = HQ∗BW∗AT n . const−w∗365

EFconst .∗EDconst . w∗¿¿

(3) For dichlorobenzene 1,4:

C =

11

TR∗BW∗AT c∗365∗CFwat

SFd∗EF const∗EDconst .w .∗EV ∗SAconst∗Z

+ 1HQ∗BW∗RfDi∗AT n . const−w∗365∗L∗V exc∗DHIRa .w∗Kws∗CFv∗EFconst∗EDconst .w∗Aconst .water

(4) For all COCs, the equations for Cavg are:

a = Kws

d +

3∗Dwat

w∗l +

Dwat

dcm∗l + K∗iw b =

K∗iw +

3∗Dwat

w∗l +

Dwat

dcm∗l Cavg = Co

a∗τ [b*τ+(

ba - 1)(e−a∗τ−1)]

Irrigation Well

Assumptions: Lawn watering duration and frequency are two hours every three days from March 1 to October 31, 82 events per year.

A Residential irrigation well: located at residential properties. Three pathways are involved: groundwater ingestion, dermal contact, and vapor inhalation

(a) Incidental ingestion

(1) Carcinogens (2) Non-carcinogens

Cing = TR IW∗AT c∗365SFo∗EF Iw∗IRIW .

Cing =HQ∗RfDo∗BW .C∗AT n . C∗365

EF Iw∗ED .C∗IRIW . C

(b) Incidental dermal contact (as with soil ABSGI is only adjusted if ABSGI <0.5, otherwise set ABSGI=1, SFd = SFo and RfDd = RfDo)

(1) Carcinogens

DAevent.AgeAdj (mg/cm2-event) =TRIW∗AT c∗365

SFo∗EV IW∗ED.C∗EF IW∗SA .C

BW . C+

EV IW∗ED . AgeAdj∗EF IW∗SABW

If tevent.AgeAdj < t* If tevent.AgeAdj > t* (all carcinogens’ tevent.AgeAdj are < t*, the equation does not apply)

Cderm = DAevent . AgeAdj

2∗FA∗K p∗√ 6∗τevent∗tevent . AgeAdj

π*CFwat Cderm=

DAevent . AgeAdj∗CFwat

FA∗K p(t event . AgeAdj

1+B+2∗(τ event )

1+3 B+3 B2

(1+B )2)

(2) Non-carcinogens

DAevent.C= HQ∗RfDo∗AT n .C∗365∗BW . C

EV IW∗ED. C∗EF IW .∗SA .C

If tevent < t* If tevent > t*(acetone, Formaldehyde, and methyl ethyl ketone)

Cderm = DAevent . C∗CFwat

2∗FA∗K p∗√ 6∗τ event∗tevent

πCderm=

DAevent . C∗CFwat

FA∗K p(t event

1+B+2∗( τ event )

1+3 B+3B2

(1+B )2)

(c) Vapor inhalation on the lawn

Assumptions: A receptor is standing on the lawn for two hours per event immediately after watering.

DA (cm2/s) = θas3.33 Dair H '+θws

3.33 Dwat

[θ¿¿ws+ Kd ρb+θas H ' ]θT2 ¿

and E (mg per cm2/s per mg/L in water)= 2∗Cw

1000 √ DA

π∗t

(1) Carcinogens (2) Non-carcinogens

Cinh¿ TRIW∗AT c∗365∗V∗W iw∗DHURF∗CF air∗EF IW−inh∗ED∗E∗A IW

Cinh ¿RfC∗HQ∗AT n∗365∗V∗W iw∗DH

EF IW −inh∗ED∗E∗A IW

(d) Total Combined Concentration:

C (mg/L) = 1

1C ing

+ 1Cderm

+ 1C inh

(B) Commercial Irrigation well: located on commercial properties. Two pathways are involved: dermal contact and vapor inhalation.

(a) Ingestion - NA

(b) Incidental dermal contact

(1) Carcinogens

DAevent (mg/cm2-event) = TR IW∗AT c∗365∗BW

SFo∗EV IW∗EDw∗EF IW∗SA

If tevent <=t* If tevent >t* (benzene only)

Cderm = DAevent∗CF wat

2∗FA∗K p∗√ 6∗τ event∗tevent

πCderm =

DAevent∗CFwat

FA∗K p(t event

1+B+2∗( τ event )

1+3 B+3 B2

(1+B )2)

(2) Non-carcinogens

DAevent (mg/cm2-event) =HQ∗RfDo∗AT nw∗365∗BW

EV IW∗ED w∗EF IW∗SA

If tevent < t*: If tevent > t*:(acetone, Formaldehyde, and methyl ethyl ketone)

Cderm = DAevent∗CFwat

2∗FA∗K p∗√ 6∗τ event∗tevent

π Cderm=

DAevent∗CFwat

FA∗K p(t event

1+B+2∗( τevent )

1+3 B+3 B2

(1+B )2)

(c) Inhalation

Assumptions – refer to resident pathway

(1) Carcinogens (2) Non-carcinogens

Cinh¿ TRIW∗AT c∗365∗V∗W iw∗DHURF∗CF ait∗EF IW−inh∗EDw∗E∗A IW

Cinh¿RfC∗HQ∗AT nw∗365∗V∗W iw∗DH

EF IW −inh∗EDw∗E∗A IW

(d) Total Combined Concentration: C (mg/L) = 1

1Cderm

+ 1Cinh

Parameters Definition unitsA Absorption factor 1 (refer to GW ingestion pathway)AHB Area of contamination for residential or C/I properties 1,500,000 cm2 for VFi or VFr

150 m2 for PEFAconst.soil Area of excavation floor and four walls 1,087,000 cm2 for VFconst or

108.7 m2 for PEFconst

Aconst.water Area of excavation floor for construction worker 22.3 m2

AIW Area of irrigation 9,000,000 cm2

ABSGI Gastrointesinal absorption fraction COC-specific, (unitless)ATc Averaging time for carcinogens 70 yearsAT.C Child averaging time for carcinogens 6 yearsATn Averaging time for non-carcinogens 30 yearsATn-III Averaging time for non-carcinogens in Category III groundwater 9/yearsATn.const-s Averaging time for soil to construction worker 0.24 yearATn.const-w Averaging time for groundwater to construction worker 0.06 yearsATn.C Child averaging time for non-carcinogens 6 yearsATnw Worker averaging time for non-carcinogens 25 years

B Relative contribution of permeability coefficient(B=Kp√MW2.6

) COC specific, cm/hour

BW Adult body weight 70 kgBW.C Child body weight 15 kgC Calculated concentration mg/kg (soil) or mg/L (water)Co Initial dissolved COC concentration 1 mg/L

Cavg Average diossolved COc concentration over time τ COC-specific, mg/LCcarc Calculated default concentration for carcinogen mg/kg (soil) or mg/L (water)Ccategory Plan A default number for each groundwater category COC-specific, mg/LCnc Calculated concentration for non-carcinogen mg/kg (soil) or mg/L (water)Cderm Calculated concentration for dermal contact mg/LCinh Calculated concentration for vapor inhalation mg/LCing Calculated concentration for groundwater ingestion mg/LCw Groundwater concentration in irrigation well exposure 1 mg/LCFair Conversion factor 1000 ug/mgCFu Unit conversion factor 1000 g/kgCFv Volume conversion factor 1000 L/m3

CFw Weight conversion factor 10-6 kg/mgCFwat Conversion factor 1000 cm3/Ld Depth of water in the excavation pit 1 mdcm Depth of water in the excavation pit 100 cm

de effective diameter of excavation pit (de = √ 4∗A const . waterπ

) 5.3285 m

DA Apparent diffusivity COC-specific, cm2/secDair Diffusion coefficient in air COC-specific, cm2/secDei Effective diffusivity (Dei = Dair*θ0.33) COC-specific, cm2/secDwat Diffusion coefficient in water COC-specific, cm2/secDether Diffusivity of ether in water 8.5*10-6 cm2/sDAevent.AgeAdj Dermal absorbed dose per event for age adjust exposure mg/(cm2-event)DAevent.C Dermal absorbed dose per event for child exposure mg/(cm2-event)DAevent Dermal absorbed dose per event for C/I worker mg/(cm2-event)DH Diffusion height or air mixing zone height 2 mE Emission rate COC-specific, (mg/cm2/sec per mg/L in water)ED Exposure duration 30 yearsEDIII Exposure duration for Category III groundwater 9 yearsED.AgeAdj Age adjust exposure duration 24 yearsED.C Child exposure duration 6 yearsEDw C/I worker exposure duration 25 yearsEDconst.s Construction worker exposure duration (soil) 12 weeks

EDconst .w Construction worker exposure duration (water) 3 weeksEF Exposure frequency 350days/yearEFconst Construction worker’s exposure frequency 5 days/weekEFIW Irrigation well exposure frequency 82 days/yearEFIW-inh Irrigation well inhalation exposure frequency (2 hrs/ev for 82 ev/yr) 6.83333 days/yearEFw Worker’s exposure frequency 250 days/yearEV Exposure event for groundwater to construction work 2 events/dayEVIW Exposure event for dermal contact with water from irrigation well 1 event/dayFA Chemical specific adsorbed, default conservatively set to 1 1 (unitless)F(x) Function dependent on Um/Ut 0.0497 (unitless)G Fraction of vegetative cover 0H’ Dimensionless Henry’s Law Constant COC-specific (cm3-H2O/cm3-air)H Excavation height 2 mHQ Hazard quotient 1i Hydraulic gradient 0.025 (unitless)IFsoil.adj Age-adjusted soil ingestion rate 114 (mg-year)/(kg-day)IRa Vapor inhalation rate for resident 15 m3/dayIRa.w Vapor inhalation rate for worker 20 m3/dayIRIW Incidental ingestion rate of groundwater from irrigation well 0.4 (L-year)/(kg-day)IRIW.C Child incidental ingestion rate of groundwater from irrigation well 0.32 (L-year)/(kg-day)IRs Construction work soil ingestion rate 480 mg/dayIRsoil.C Child soil ingestion rate 200 mg/dayIRsw Worker soil ingestion rate 100 mg/dayIRw Daily adult water ingestion rate 2 liters/dayIRw-III Daily adult water ingestion rate for category III groundwater 1.4 liters/dayK Hydraulic conductivity 1.7*10-4(cm/sec)

Kas Soil-air partition coefficient (Kas = H 'K d

) COC-specific (g-soil/cm3-air)

Kd Soil-water partition coefficient (kd = Koc*foc) COC-specific (cm3-H2O/g-soil)Koc Soil organic carbon-water partition coefficient COC-specific (cm3-H2O/g-Carbon)Kp Dermal permeability coefficient (LogKp=0.66LogKow-2.8-0.0056*MW)COC-specific, cm/hourKow Octanol-water partition coefficient COC-specific (cm3-H2O/cm3-octanol)Kws Overall mass transfer coefficient COC –specific, m/s

Kws = 2.78∗10−6∗(

Dwat

Dether)

23∗4.82∗10−3∗V exc

0.78∗(ρG∗D air

UG)

0.67

∗de−0.11∗H '

2.78∗10−6∗(Dwat

D ether)

23 +4.82∗10−3∗V exc

0.78∗(ρG∗Dair

UG)

0.67

∗de−0.11∗H '

l Characteristic length for diffusion 30.48 cmL Length or width of excavation 4.7 mLS Length of contamination area 21 mMLE Most likely exposure (1.4 L/day*235 days/year*9 years) 2961 LitersMW Molecular weight COC-specific, g/molePEF Particulate emission factor 2.917*1010 , m3/kgPEFconst Particulate emission rate in construction work scenario 9.0*108 m3/kgRfC Inhalation reference concentration COC-specific, mg/m3

RfDd Dermal reference dose (RfDd = RfDo when ABSGI >50%) COC-specific, mg(kg-day)

RfDi Inhalation reference dose (RfDi = RfC∗20

70 ) COC-specific, mg/(kg-day)

RfDo Oral reference dose COC-specific, mg/(kg-day)S Pure compound solubility in water COC-specific, mg/LSA Adult skin area 18,000 cm2

SAconst Construction worker skin area 6170 cm2

SA.C Child skin area 6,600 cm2

SFd Dermal cancer slope factor (SFd = SFo when ABSGI >50%) COC-specific, mg/(kg-day)-1

SFi Inhalation cancer slope factor (SFi=URF∗1000∗70

20 ) COC-specific, mg/(kg-day))-1

SFo Oral cancer slope factor COC-specific, mg/(kg-day))-1

τ Exposure interval (3 weeks for groundwater to construction worker) 1.8144*106 secondsτevent Lag time (τevent = 0.105*100.0056*MW) COC-specific, hour/eventt Exposure interval for vapor inhalation after watering 7200 secondstevent Exposure duration in irrigation well scenario 0.73 hours/event

Assume sufficiently warm (>700F) for 60 of the 82 events and 1 hour sprinkler play time (RME bathing time, USEPA RAGS Part E, 2001), (60*1)/82 = 0.73

tevent.AgeAdj Exposure duration for resident contact with water from irrigation well 0.48 hours/event

for age adjust, tevent.AgeAdj = 0.73∗6+0.42∗24

30 = 0.48 hours/event

tevent.const Exposure duration for construction worker 2 hours/eventt* Time to reach steady-state COC-specific, hour

If B<= 0.6, t*= 2.4*τ event

If B > 0.6, t* = 6*τ event*{[2(1+B)2

π−1+3 B+3 B2

3 (1+B)]-√[

2 (1+B )2

π−1+3 B+3 B2

3 (1+B )]2

−[ 1+3 B+3B2

3 (1+B )]2}

T Resident soil vapor exposure interval 9.4608*108 seconds TC/I C/I worker soil vapor exposure interval 7.844*108 secondsTconst Construction worker soil vapor exposure interval 3.78432*108 secondsTR Life time cancer risk for Category I groundwater 10-6

TRII-III Life time cancer risk for Category II and III groundwater 10-5

TRIW Life time cancer risk for irrigation well 10-5

TRf Life time cancer risk for future exposure 10-4

V Wind speed in mixing zone 2.25 m/secVexc Wind speed in the excavation pit 0.225 m/secUg Viscosity of air 1.81*10-4 g/(cm*s)Um Mean annual wind speed 4.5 m/secUt Equivalent threshold value of wind 12.8 m/secURF Inhalation unit risk factor COC-specific, m3/ugVFi Soil-to-air volatilization factor for C/I worker COC-specific, m3/kgVFr Soil-to-air volatilization factor for resident COC-specific, m3/kgVFconst Soil-to-air volatilization factor for construction worker COC-specific, m3/kgw Width of excavation pit 470 cmWiw Width of lawn 30 mZ Dermal factor COC-specific, cm/eventβ Dry soil bulk density 1.7225 g/cm3

θ Total soil porosity 0.35 (unitless)θa Volumetric air content of soil 0.22 (unitless)θw Volumetric water content of soil 0.13 (unitless)θas Volumetric air content of top soil (lawn) 0.1 (unitless)θws Volumetric water content of top soil immediately after irrigation 0.4 (unitless)θT Total soil porosity of top soil (lawn) 0.5 (unitless)

ρb Dry soil bulk density for lawn soil 1.67 g/cm3

ρg Density of air 1.2*10-3 g/cm3

ρs Soil particle density 2.65 g/cm3

foc Fraction of organic carbon in soil 0.002foc.iw Fraction of organic carbon in lawn soil 0.02

Revised September 2, 2011