HomeMy WebLinkAboutMabel Addition Block 124 - Cleanup Level Calculation Kearney Street Substation 1998.01.0901/13/98 llltlN 1l:il FA-I l?5 861^ ^q0;0 rjE(J ENGIj'iEERS
Ianuary 9. 1998
a oDr
Geo$1f Engirtccrs
Ct)rls(r lting l,ogi netrJ
altd tieoscientists
() f licr-.s in \\'irs lt i rtlton.
()reqrru. it;lt! .\litskit
Pugec Sound EnergY
Environmental Services
P.o. Box 97a34 ri'fER-04
Believue, Washingrorr 98009-9734
A*ention: Barry Lombard
Summary Report
Interim TPH PolicY - N'ITCA Method B
Cleanup Level Celculation
Perroleum-Hydrocarbons in Soil
Kearney Street Substation Site
Pon Townsend, Washington
File No. 0186'385-85
INTRODUCTION
This lener presents rhe resulrs of GeoEngineers' calculadon of tvlodel Toxics Conn'ol Act
(14TCA) lvlerhod B cleanup levels for insulation (urai:sformer) oil- and hydraulic oil-related
hydrocarbons derected in soil in rhe eastern (undeveloped) po*ion of Puget Sound Energy's
(PSE) Kearney Street Substation site in Port Townsend, Washingtgr' The MTCA Method B
cleanup levels presented herein were calculated using the Washin$on State Department of
Ecology's @cology) Inteim lweryrerive and, Potiq Statement, Cleanup of Total Petroleum
Ilyd.rocarbons (lnterim TPH Policy). Our services were completed at the lequesl of Barry
Lombard of pSE in accordance wirh our existing agreemetrt wirh PSE (Contract No' BX0I07^1-
c01A).
DISCUSSION
Recent sftdies (Insulating oii Fate and Transpoil Report, May 1996, prepared for Bonneville
power Administration et. al. by CHzMHill) havs shown that the more toxic constituents
rypicajly associated with many petroleum products such as semi-volatile organic compounds,
volatile organic compounds and metals are present at tracs eoncentratiorLs or are not detectablo
in insulating oils. The studies also have shown that insulating oil has a relarively high
viscosity, migrates through soil relarively slowly. and has a low Potential for volatiiization'
leaching or lransport to ground watef. Additionaliy, hydrauiic oil rypically does not contain
high concentrations of volatile andlor more toxic compounds found in some peroleum
GccIngirrccls. lttc
.r+l(t lr+tlr Arenue \.[.
iicCnr,:ns.
"\n
910ij
Ttltpilor r,"' t +1"; 1 ljdl'6U(lil
lru iiti r.S6i{0i0
'*..rctsoel' gitlef rl. col::
01r12,'fr$ lI0)- 1l:51 FA-\ lt5 ,161 B0;(l (;E() EN(;INEERS
Puget Sound Energl
January 9, 1998
Page 2
hydrocarbons. Renrediarion oi perroleum-h),drocarbon spills hiscoi:ically has been c.ompleted
using d:e lr{odel Toxics Conrrol Act ftlTCA) Merhod .{ cleanup levels tbr petroleum producu.
The MTCA iv{ethod A cleanup levels for petroleum hydrocarbons in soil (200 miJligrams per
kilogram lmg/k-ql for diesel- and heavy oil-range hydrocarbons ard 100 mglkg for gasoline-
range hydrocarborrs) cannot be adjusted to account for specific properties of petroleum products
such as rhe absence of tlre moretoxic constituents in insulating and hydraulic oils. The Ecology
Inrerim TPH Policy allows for calcularion of a N{TCA Method B cleanup level for the
petroleum prociuct in soil based on rhe actual constinrenEs present in the petroleum. PSE
requested rhar GeoEngineers use interim TPH Policy merhodolory to (1) calculate site specific
insularing and hydraulic oil cleanup levels, and (?) evaluate *re regulatory significanc.e of
remainirrg insularing and hydraulic oils in soil at the subject site. A detailed discussion of the
Interim TPH Policy methods is preseoted in Anachnrent A'
CHEMICAL ANALYSES
Two soil samples (TPa and HA-l) were obkined by GeoEngineers, from portions of the
.sire whereprior chemical analysis confumed the prssence of insulating oil (i'Pa) and hydraulic
oil GIA-1). The approximate locations of these soil sam!les are shown on Figure 1, affached.
The soil samples were submirted to North Creek Anail'rical of Bothell, Washington for
chemical analysis of diesel- and heavy oil-range petroleum hydrocarboru by Ecology lvlethod
NWTPH,D extended and benzene, ethylbenzene, toluene and xylenes (BETX), methylene tert-
butyl ether (MTBE), naphrhaiene, volatile petroleum hydrocarbon (VPII) fractions and
exiracrable petroleum hydrocarbon (EPH) fractions using Ecology Interim TPH Policy
methods. The chemical analyticai resuirs for TP*4 and HA-l ale sufiImartzd in Tables I and
2, respectively. The laboraory report is presented in Attachment B.
Insulating oil was detected in TP4 at a concentration of 2,020 milligrams per kilogram
(mg/kg). Aliphatic EPHs were detected in the EC12-16, EC16-ZI, and EC21'34 ranges.
Aromaric EPHs rvere detected in he EC15-21 and EC21-34 ranges. Volatile petroleum
hydrocarbon fractions were frot detected in the TP4 sample. Polyrtuclear aromatic
hydrocarbons (PAHs), BETX, N,ITBE and naphrhalene \yere not detected in the TP4 sample.
H),draulic oil rves detected in H.{-l at a corrcenrarion of 63i nrgikg. Aliphatic EPHs tvere
derecred in rhe EC16-21, arrd ECz1-34 ranges. Aronratic EPHs were detected in &e ECz1-34
range. PAHs were derecied in HA-1 at concentrs.tions less rhan MTCA cleanup levels- BETX,
MTEE and naphthalene wete nol detected in tire HA-l sample-
MTCA METHOD B SOIL DIRECT CONTACT CALCULATIONS
Petroleum products, including insulating oil and hydraulic oil, contain multiple fractions
and irrdiuidual compounds that have associated norrcarcinogenic health effects. MTCA
@ ou;
GeoEnginecr5 File F;o, 0l S6-385-85-1 150
01/1:/98 llrlN 1{;' 3 Fi\-{ l!t 8dl- 605{)(;E(] EN(;I-\EERS
Puget Sound Energ.,
January 9, 1998
Proo i
scipulates that individual hazard quo[ients associated with these fractions are additive, and rhar
the total hazard index (rhe sum of all individual hazard quotien',J) should nor exceed 1.0 for the
risk to be considered acceptable.
We calculaced tlrat rlie hazard irrdex for the insularing oil in soil sample Tp-4 is 0.46 as
shown in Table 3. Carcinogenic contpounds were not detected ar concentrations of re$llatory
significance in TP-4, A sice-specifi,: Medrod B soil cleanup level prorective of human heahh
direct contsct (non-carcinogen) exposures was calculared for insulating oil using rhe MTCA
Method B equations and uhereference dose values as shown in Table 3. The lr{erhod B cleanup
level *,e calculared for insulating oil iir soil at *ris sile is 4,241mglkg.
We ca.lculated that the haeard index for the hydraulic sil in soil sample HA-l is 0.il as
shown in Table 4, Carcinogenic compounds were not detected at concentrarions of reguiatory
significairce in ihe soil sampie tested. A site-specit'ic lr{ethod B soil cleanup ievel protective of
human health direct contact (noncarcinogeir) expcsures was calculated for hydraulic oil using
the Ir{TCA \{erhod B equations ald the reference dosevalues as shqq'n in Tabie 3, The Medrod
B cleanup level we calculated for hydraulic oil in soil at rhis sire is 3,864 mg/kg.
The Method B cleanup levels are based on (l) evaluation of the direct conracr exposure
pathway, and (2) the ratio of aliphatic to aromatic consiicuents. The cleenup levels calculated
based on evaluation of rhe soil-to-grcund water exposure parhway (described below) would be
significantly higher. This difference between the caiculated cleanup Ievels reflecrs (t) the
relatively conservative surrogates used in the direct-conhct calculations arrd (2) the reiatively
low solubility of both insuladng oil and hydraulic oil.
POTENTIAL SOIL-TO-GROUND WATER TRANSPORT OF HYDROCAHBONS
As described in Attachment A, the Interim TPH Policy aiso requires ttrat soil contamination
be evaluated relative to its potential to migrate to ground water. In accordalce wi*r the Policy,
the evaluation of this fate and rransport pathway was based on a determination of whether TpH
remaining in vadose eone soil could cause exceedence of the lvfTCA Method A ground warer
cleanup level for TPH of I miiligram per liter (mgll). The concenrration of TPH parritioning
from soil to soil pore waler was estimated using Raoult's Law. Raoult's Larv is used to
es'Limale resultart chernical concenttations dissolved in water q,hsn rnore than one chemical
compound fifPH fraction) is present in soil. Each TPH fracrion has a different solubility in
watef . Based on the reiative concentration of each fraction, Raoulr's Law was used to estimate
the resultant concentration of TPH in pore water. Consistent with the Interim TPH Policy, tire
estimated concentration of TPH in pore water using Raoult's Law rvas then assumed to directly
enter the grcund water (assumes that contaminared soil is in direct centacr wirh ground water).
Once the Pore water enters che ground water, it is assumed under the Interim TPH Policy ttrat
the concentrations of dissolved TPF{ will be diluted by 2A times before reaching a drinking
@ottg
GcoEnginaErr Fiie ]io. 0 r 56-185-85-l I 50
r.rl,i1!;98 liI0N 1{:'1t FA-I l?5 861-605()
Puget Sound Energy
January 9, 1998
Page 4
CJEO ENGI]{EER,S @ttai
rvater well, This ,lilureC concentrarion of dissolved hydrocarbons is comparerJ [o the N'ITCA
fufethod A ground rlaler clearup level for TPH of I mg/I.
Using (1) tire merhods described above, the VPH and EPH faction data for TP'4, and (3)
the grearest concenkation of insulating oil detected in soil at the site (2,QZQ nglkg in TP'4), &e
predicred TPH concentration in ground rvater is approximately 1.8xi0-r mg/l as shown in
Table 5. This concentration is significa.ntly less rhan the MTCA Method A cleanup level for
TPH of I mg/}, Based on rhe soil-to-$ound waler [ranspofl eva]uation in accordance wittr the
Interim TPH Policy, irsulating oil remaining in soil at the sire would not impact ground water,
even if ir was in direct cenlact witir ground waler.
Using (1) rha methods described above, (2) the grealest concentration of hydraulic oil
derected in soil at rhe sir,e (?,910 mg/kg detected in a prior sample from the viciniry of HA-l)
(3) rne rarios of hydrocarbon fractions detected in HA-I, the predicred TPH concentration in
ground *,arer is appro.<imarely 8.3x10-5 nrg/l as shown in Table 6. This concentration is
significanrly Iess *ra.n the VITCA lvlerhod A cleanup level for TPH of 1 nrg/I. Furthermore the
hydrocarbons in soil are not in direct contact with ground water, as use arrd Raoult's Law
assumes. Therefore, concentrations of dissolved hydrocarbons if any, would expect to be less
than 8.3x10'J mg/I. Based on the soil-toground water transport evaluation in accordarce with
rhe Inrerim TPH Policy, hyCraulic oil remairring in soil at the site would not impact ground
Tvater, even if it was in direct contact with ground warer'
CONGLUSIONS
Based on chemical analyrical resul6, Ecology's Interim TPH Policy guidance and the
resulu of prior sire sardies, itis ouropinionthat no further remedial action by PSE is necessary
in the eastern portion of PSE's Kearney Street substation site to satisfy the regulatory
requiremenrs of MTCA for insulating oil ald hydraulic oil relared petroleum hydrocarbons.
CSemical analytical resulu indicate that residual insularing oil concentrations in remaining
soil in the eastern portion of the sire are less than the calculated MTCA Method B cleanup level
(4,242 mglkg) and are protective of hun:an health for the direct contact and soil-to-ground
warer exposure pathways. Chemical analytical resuits did nor derect VPHs in TP4- Based on
our knorvledge of fie character of insulating oil and the chemical analytical results, it is our
opinioit thar remaining insulating oil concentrations also are protective of humarr health for the
soil-to-vapor exposure Pathw aY.
Chemical anall'rical results indicate that hirdraulic oil concenrations in remaining soil in rire
eastern ponion of rhe site are less than rhe MTCA Method B cleanup level (3,864 mgikg) and
are prorective of human heal*Jr for the direct contitct and soil+o-ground water exposure
pathrvays. Chemical analyrical resulcs did not detect VPHs in HA-1. Based on our knorvledge
of the characrer of hydraulic oil and rhe chemical aaaJytical results, it is our opinion that
GeoEngioear:l File No, 0l E{t-385-85'l 150
01/1119,9 ]ttlN 1l;5. FAI 115 861 6fi50 GEI] ENGINEERSaI
Puget Sound Energy
January 9, 1998
Page 5
remaining hydraulic oil concentrations also are proteclive of human health for the soil'co'r'apor
exposure pathway,
LIMITATIONS
This report has been prepared for use by Puget Sound Energ.,' and its authorized agents,
This report is not intended for use by others, and the information eontained herein ruay nol be
applicable to o$rer sites. Regulatory policy regarding risk-based evaluatiorts of petroleum
hydrocarbon contamination continues to be formulated b1' Ecology. The Interim TPH Policy is
a conservative and temporary measure inrended to allow for dre use of a risk'based approach to
petroleum hydrocarbons while final policy is developed. The policy describe,l herein is subject
to future regulatory revisions.
GeoEngineers has performed this study in accordance with our agreement with Pugel Sound
Energy (Conracr No. BX0l0l74-C0lA). Within the limitations of scope, schedule and budget,
oul sEn,ices have been executed in accordance rvi*r generally accepted environmental science
practices in this area at rhe time rhis repoit was prepared. No *'erraary or other conditions,
express or implial, should be understood.
tAooS
6soEngineirs Filc No. o 186-38i-85-l !50
ltiL2,,98 )Ir:tN 1{;53 FAI {?5 861 60;0 (;EO ENGII,iEERS-)
I'uget Sound EnergY
January 9, 1998
Page 6
We appreciare rhe oppornrniry to assist you rvith this dats evaluation. Please cail if 5'ou
have any queslions.
Yours very truly,
GeoEngineers, In6
@ oos
tu{-. {-' 4-tl-{
Gary R. Stevens
Staff Hydrogeologist
Kurt R. Fraese
Arsociate
6RSTKRF:ja
I.b. p :\00Ot0099\01 86385\iinalr\01 E63E5ltr.doa
Anachnents
Two copies submitted
cc: JeffRandal
GcoEngintcrt File )to. 0t86.385'85-l I 50
TABLE 2SOIL CHEMICAL ANALYTICAL RESULTSHYDRAULIC OILI(EARNEY STREET SUBS-I-ATIOI.I SI'TEPORT TOWNSEND, WASHINGTONtstsIJ'<t(F'1tsfilr.C)'4,P'4*-lcvr{P-,@UIExtractable Petroleum Hydrocarbons 3 (mg/kglrllrl'z,zfr,t47i,NDNDArornaticsEC21-3499.0EC162-1NDVolatile Pctroleurn l-lydrocarbons a (mgikgiAromaticsEC12,13EC12-r6NDEC10-12EC10-12NDEC8-10NI]ECz1-34314AliphaticsEC10-12EC16-2117-9ECB-I0EC12-16NDECS-8EC10,12NDECSSECB.1ONDPolynuclear fuomaticHydrocarbons & Compounds {(mg/kg)--01BBenzo(alanthracene -- 0.048SBenzo(a)pyrene - 0.0394Benzo{b)lluoranthene -- 0.083tlenzo(ghilperylene -- 0.01 57Benzo(k)fluoranthene - 0.0598Chrysene - 0.0598Fluoranthene - 0.101I deno( 1,2,3-cd)pyrene -- -0.024 4Phenanlhene -- 0.0614Pyrene -- 0-0866TPH ? (mg/kg)neavy url-Range 3631Diesel-RangeND$anrpleNumberIl-tA-1NsFtsl':100Dt0099\O I 1163 85\lirrds\] ablts.xlsll' I
(11/1:,.98 .{JN 1i;(){) F_\f, l?5 861 6{)50 (:iErl EN-(;I.\-EERS
TABLE 3 (Page 1 of 2)
HAZARD INDEX AND METHOD B CLEANUP LEVEL CALCULATICNS
INSULATING OIL
KEARNEY STREET SUBSTATION SITE
PORT TOWNSEN D. WASH I NGTON
MTCA METHOD B CLEANUP LEVEL CALCULATION
Tcial Hydrocarbofi Concentraticn Delect:d = 1,718 + 235 = 1'953 mg/kg
c/oTotaialiphatic fraction - 1,718 mg/kg / 1,953 mg/kg x 100 = 88%
% Totel aromatic fraction = 235/1.953 mg/kg xlAA = 12Yo
I(TCA Method B Cleanup Leve/ = 4,241 mg/kg
This Method g c{aanup level results in a Hazard lndexof 1.0with the aliphaticfraciion representing
gg% and the arornaiic fr-action representing 12% af the tctal hydi'ocaibons as shorvn below:
Total aliphaticfraction =3,731mg/kg (88% of 4,241 mg/kg)
Total aromatic fraction = 510 mg/kg (12% af 4,241 mg/kg)
Notes appear on Page ? of ?
@oLz
HQFactorMultiplierORfDoundCom
0.00
0.00
0.00
0.10
0.302.08E-04
4.178-04
1.25E-04
6.25E-05
6,25E-06
4.178-44
0.1
4.7
2
0.03
0.06
0,03
1.25E-05
1.25E-05
1.25E-05
1.25E-05
1.25E-05
1.2sE-05
Total aromatic
RofiTar.la
Ethylbenzene
Toluene
Xylenes
Total aromatic+B-E-X
otal aliph
HQMultlplierFactorORfDComound
0.00
0,00
0.00
0.21
0.782.08E-04
4.17E-04
1.25E-04
6.258'05
A ?qtr-nA
417E-AA
0.1
0.2
2
0.03
0,06
0,03
1.258-05
1.25E-05
1.258-05
1,25E-05
1,25E-05
1.25E-05
Totalaromatic
Beneene
EthYlbenzene
Toluene
Xylenes
Total aromaiic+B-E-X
aliphatic
P:\000ro099\0 I 8f:i $ 5\fi nals\Tablcs.xls\T'l
0L/ L2/ S8 llrlN 15 : 01 F.{X {ti 'f\00;o
1 TABLE 3 (Page 2 of 2
-(JEt] ENGINEERS a @0L.3
)
J
Fr\000to099\0 I 86i 8S\tinals\Tablcs.nls\T4
0L/12,'gg )ION 1;:01 F-^\'I t35 86.1 8050 GEO EN(;INEERS
TABLE 4 (Page 1 of 2)
HAZARD INDEX AND METHOD B CLEANUP LEVEL CALCULATIONS
HYDRAULIC CIL
KEARNEY $TREET SU BSTATION
PORT TOWNSEN D, WASHINGTON
@t)U
lculationndexH
HQMultiplierFactorORfDndCom
0.00
0.00
0,00
0.04
0.07
1,25E-0s
1 25E-05
1.25E-05
1 25E-05
1 2qtr-ni
6,258-05
6.25E-06
4,17E-04
4.17E-04
2.081.2sE-05
1.25E-05
U.UO
0.03
0.1
a.z
2
0,03
Total aromatic
Benzene
Ethylbenzena
aromatic+F'E-X
aliphatic
oluene
Xylenes
[4TCA METI{OD ts CLEANUP LEVEL CALCULATION
Total Hydrocarbort Concentration Detected = *r3? + 99 = 431 mg/kg
% Totaialiphaiic iraction = 332 mg/t(g / 431 mg/kg x 10A = 77%
% Total aromatic fraction = 99/431 mg/kg x 100 = 23%
MTCA Method B Cleanup Level = 3,864 mg/Rg
This Method B cteanup lavel results in a Hazard lndex of 1.0 with the aliphaiic frection representing
T7% and thE aromatic fraction representing 23% ol the total hydrocarbons as shown helow;
Totalaliphaticfraction=2,976mglkg(770/oof3'864mg/kg)
Totalaromaticfrection=865mg/kg(23%of3'390mg/kg)
HO
ili; :i:iii;;lS€Fl qFf'ttl+
Multiplier
ilillii;i'lii;*itii:$l;r11
l
FactorORfDComound
0.00
0,00
0.00
0.37
.6t2,088-04
4,17E-04
1.25E-04
A "(tr-n66.25E-06
4,178-04
1,25E-05
1.25E-05
1.25E-05
1.25E-05
1 "5F-n(1 258-05
0.1
4,2
/-
0,03
U.UO
0,03Totalaromatic
Benzene
Ethylbenzene
Toluene
Xylenes
Total aromatic+8-E-X
lii:ii
l:i!;i
Ifii
liii:L
i
Ii;ii
I ir:
Totatalip
Notas appear on Page 2 of 2
p'16q91q99!\0 1 $ 63 85\t-rnc,ls\Tabl cs.xl:\T3
r)1/1!/98 ]lrlN 15; tll F.{I {?5 ,36-1"_6050,\
irl
) TABLE 4 (Page 2 of 2)
(:;E{] ENGINEERS
l
@or.:
)
P1000tDtr99\0 I $63 8 5\f inEls\TEblcs.tls\Ti
C,tstsIJ(tCoc.zF(Jl,!J,r1'/4'l-l{vr(oFoc.lITABLE 5PROJECTED TPH CONCENTRATION IN GROUND WATER 1INSULATING OtLKEARI,IEY STREET SUBS'TATION SITEPORT TOWhISEND, WASHII{G'TON14Ot4z.4.ztdrrlniJDCgrvtr{nrgi Li0.ooDDo.ooD00.00000.00000_o0000-00000,00000_00000.00'i}00.001Bo.o000.{,0Qr.sQ00{.DF202020202fr202020202020EffectiveSolutrility(mstr)0.00000o.000000.000000.000000.000000.000000.000000.000000.o0000o.000000.00 t 65S [rns/L)o.33o.o2Go.000590.0000010_000001't7805201r,5.80,5r0_o066x0.000.000.000.040.7I0_000-000.00o.000.000.25mMQles0-00000.0{000.otxi70.00400.001 c0-00000_00000-00000.uto{}0.o0050.0006r*!0'$0?fiiiiiiiMW{ginrcl)13016020t}27027078971301501!0240Per<nnt oIrnixlure0.00%0.00066.9t%55_30%25-76n/o87.9]o/s0.00%o.00%0.00%0.00%5_17%6.869'ot2-o3%Concenlration{ms&s}0013510805031718oo00t0t13.1235FractionEC >B-10 {9-0}EC >10-12 (11_0)EC >12-16 {14.0}EC >16-21 (1S.0)EC >2t-34 (2r1.0)TO]-ALALIPHATICSBenzene (G.5)Toluenc {7-6)EC >10-12 tr t-0iEC >r2-1G {14.0}Ec >r6-2t {11}.0)EC >21-35 (20.0)TOTALAROMAIICSAliphaticsAronralacsNc.FCDIriv)00lo09tVl I 86l8i\linalsTl'ablcs.x ls\'[ fi
TABLE 6PROJECTED TPH CONCENTRATION IN GROUND WATER 1HYDRAULIC OILKEARNEY STREET SUBSTATION SITEPORT TOWNSEND, WASHINGTONtsFl'J(o(nc.,ztsy.'*-'rl'P,4'l-IJvr€<,ts.3(/l,nfrl.-,rrl2zlflrrJnVDNgP-tCgwtr (rng/L)0.00000.00000.00000.0000o-00000.o0000.00000.00000.00000.00000.0001,i8i253?6E;05DF2020202020202020202020EfiecliveSotubility(mg/L)0-000000_000000_000000.000000"000000.000000,000000.000000.000000.000000_00165S (ms/L)0.330_0260.000590.0000010_00000117 B0520255.{}0.s10.0066X0.00o.000_000-04o.710.000,000.000.000.000.25lri.,i.lti00imMoles0_00000.00000.00000.00050.00790.00000.00000.00000"00000.00000_0028MW{g/mol}13016020027A2797B92130150190240Perceni ofmixture0_00%0.00%0.00964.15%72-87%77.02o1n0.00%0.00%o.o0%0.00%0.00%22.58%22_98%Concenlrationirng/kg)0001222142.42264.40oo00€75.067s.6FraciionEC >B-10 (S.0)EC >10-12 {11.0}EC >12-16 (14.0)EC >16-21 t1s.0iEC >21-34 t2B.O)TOTAL ALIPHATICSBenzene (6.5)Toluene (7.6)EC >10-12 (11.0iEC >12-16 (14.0)EC >16-21 t19.0)EC >21-35 {28.0}TOTAL AROMATICSAliphaticsAromaticsl''L00utgU99l0tSfiJl 5ilirruls$'rblcg.r I sTl r
01,'1r.'98 lIr)N 15:05 FA-I lt; 8dl 605{)(:iE(J E]'i(]I)EERS
ATTACHMENT A
@ org
rl1"1t,'9,9 )l{J.\- 1i:{i5 F.{-\ lt5 861 0050 GE(J EN(.;INEERS
ATTACHMENT A
INTERIM TPH POLICY METHODS
The MTCA cleanup regulations require that the evaluailon of soil contanrination and
determinatiorr of soil cleanup levels be bued on consicieration of direct contact and on
prorecrion of ground water, Similarly, the Interim TPH Policy requires consideration of LrotJr
components in evaluating petroleum contamination and arriving at a soil cleanup level. To
evaluate the level of contamination and calculate a soil cleanup level tbr t}e site's i.ttsulating oil
in accordance with the Interim TPH Policy, iderrtii'icacion of rhe petroleum product hi'drocarbon
fracrions a:rd quanrification of their toxiciry (using surrogates) arrd transporl characteristics were
required. Considerations of current and future site use also q'ere necessary to apply the
appropriate MTCA merhod. For this site, rve made the most conservative assumption that the
site must meet residential cleanup srandards; drerefore, MTCA Method B rvas used for
evaluaiion of contamination and in calculating a soil cleanup level.
The h,{TCA i{erhod B formula for evaluating soil contamination and calculating a hun:an
hea.lrh risk-based soil cleanup based on direct contact, as applied in rhe Interim TPH Policy,
considers only the soil irrgestion exposure pathway. This was considered sufficient for
contaminaiion evaluariorr and calcularion of an insulating oil cleanup level in soil. The potential
for inhalatiorr of vapors from insulating oil conramination is considered negiigible because of its
low volarility. Soil-ro-ground water transport of insulating oii and subsequent ingestion of
ground rvater also was considered in our assessment. The reader is referred to the Interim TPH
Policy @cology Publication ECY 97-5m) for background informatiorr and assumptions that
pertain to the use of the Interim TPH policy.
SURROGATE APPROACH
Perroleum products rlpically are cofiiposed of thousands of individual chemicals. Toxiciry
criteria rhar relace the intake (dose) of a chemical ro a re.sponse are available for only a handful
of rhe individual chemicals rhat may be present.in petroleum produccs. A cleanup level cannot
be calculared for individual chemicals (or for petroleum products) unless a toxiciry criterion,
such as a reference dose for a non-carcinogen or a potency factor for a carcinogen, is available.
The Inrerim TPII Policy uses a surrogate approach to account for compound-specific data that
is noc ),et available. In ihe surrogate approach, a reference compound is identified as e
repiesentative of individuai perroleum hydrocarbon fraciions. These reference comPounds are
selected because tlreir toxiciq, is relatively well characterized in that eirher a reference dose or
potency factor is available, or a dose-response value can be developed from ai'ailable toxicity
data. The toxiciry criterion identit'ied for the reference compound is then assumed to rePresent
a surrogale toxiciry criterion for the associated h)'drocarbon fraction'
For the purpose of identifying surrogate toxicify criteria for hydrocarbon fractions,
petroleum hydrocarbons are divided into broad chemical classes. Surrogate toxiciry criteria are
qozo
GeoEnginagrs d A.l Filc No, 01$6-385-S5-t t50
01.'ll;98 )I0I 15;{)O F.{-\ .l?5 861 6ri50 (.;EIJ E\GINEERS
then iderrtified for each group of compounds using the methods desribed above. Ecolog} has
selecred one compound representing the aliphatic tiactions (n-hexane) and one compound
represenring ihe aromaric fractions (pi,rene) that likely have the most consen'al,i\re loxicity
criteria. Surrogare crireria for u.rher h.vdrocarbon fractions are likely multiples of these. Until
sufficient dara are made available for developing surrogate toxiciry criteria for the other
hydrocarbon fracrions, rhe Ecologr- Incerinr TPH Policy requires that (l) all eJiphatics be
grouped toge,Jrer, (2) all aromatics be grouped together and (3) the aliphatic and aromatic
groups be represenred by the toxiciry criteria for n-hexane and pyrene, respectively- This
surrogare approach was userl in our calculation of ihe Metirod B cleanup level for insulation oil
in soil based ort direct contacl.
The surrogare merhod used in the Interim TPH Policy for ei'aluadon of contamination and
in calculaEing pecroleum hydrocarbon cleanup levels does not account for the noflcarcinogenic
toxicity contriburion of etirylbenzene, toluene, and xylene. It also does not account for the
carcinogenic health effect conriburion from benzene and carcinogerric PAHs that may be
present in rhe petroleum producr. These compounds are quantified and evaluated separately,'
and cleanup levels are calcutared for each compound using rheir specific reference dose or
potency factors. Evaluaiion of peuoleum contamination and calculacion of Method B cleanup
levels completed for rhis srudy account on-ly for petroleum hydrccarbons in the absence of rhese
co,r:rpounds; benzene was nor derccted and carcinogenic PAHs were less than N4TCA Method A
cleanup levels in che soil sample oh'tained from rJ:e subjert site.
.4lthough a reference dose vaiue is not avaiiable for benzene for non-catcinogenic health
eft'ects, rhese health effects a.re accounted for in evaluating the contamination and in calculating
the TPH cleanup Ievel by the surrogate approach. The lnserim TPH Policy assumes that
benzene has noncarcinogenic health effects as well as its carcinogenic health effecu and
assumes rhat rhe reference dose for benzene is equal to the surrogate value for aromatics (0-03
mgikglday).
The hydrocarbon fractious ald their associated surrogate toxiciry criterion values for the
Ecology Inrerim TPH Policy are suilrrnafized in Tables 3 and 4. The hydrocarbon compounds
are all considered non-carcinogenic, based on the toxicity informarion currencly available.
Therefore, only ref'erence dose (ORFD) values are provided-
Wo2r
GgoEngin.srt Filc No. 0 t86.3S5-85- t 150
ceo Sflnngineers
January 8, 1998
Mr. Jeff Randdl
City of Port Townsend
Building and Community Development
540 Water Street
Port Townsend, Washington 98368
Dear Jeff:
Re: Ecology's Interim TPH Policy
In response to your request, we have attached a copy of the Washington State Department
of Ecology's Interim Interpretive and Policy Statement 'Cleanup of Total Petroleum
Hydrocarbons" (Interim TPH Policy). A letter documenting our use of the Interim TPH Policy
in calculating Model Toxics Control Act (MTCA) Method B cleanup levels for Puget Sound
Energy's (PSE) Kearney Sqbstation property will follow. It is our experience that Lynn Coleman
Qffi) 40[4194 at Ecology has an excellent understanding of the policy and its formulation.
Please call me QM) 728-2674 or Barry Lombard of PSE (206) 224-2102 if you have
questions or require more information.
Yours very truly,
GeoEngineers, Inc
Kurt R e
Associate
KRF:cdl
Docurncot I.D. P:\0 I 863t5.LTR
Attachment
cc: Barry l-ombard, PSE Clty of Fort Townsend
FIECEIVED
JAN 1 q 1998
Consulting lngineers
and Geoscientists
0fTices in Washington,
Oregon, and Alaska
GeoEngineers, Inc.
Plaza 600 Building
600 Stewart St., Suite 1215
Seattle, WA 98101
I'elephone (205) 7 28-267 4
F.ax (206) 12&2132
rwwvgeoengineers.com
Printsd otr. recyclsd gotrst
lull*lq & (omnunfi Dowlepncnt
a
Washington State Department of Ecology
Toxics Gleanup Program
INTERIM INTERPRETIVE AND POLICY STATEMENT
Cleanup of Total Petroleum Hydrocarbons (TPH)
1
ti
1
)
J
Ecology publication No.
January, L997
ECY97-600
TO
.fanuary 15, L997
Interested Persons
FROM Carol Kraege
Toxics Cleanup Program
SLIBJECT: Interim TPH Policy
Attached is a copy of an "Interim Interpretative and Policy Statement--Cleanup of Total
Petroleum Hydrocarbons (TPH)" (nterim Policy) affecting cleanups of petroleum
contamination. This Interim Policy is the result of the recommendation of the Model ToxicsContol Act (MTCA) Policy Advisory Committee that the Department of Ecology adopt an
Interim total pefroleum hydrocarbons (TPFD policy. Our task was to look at methods being
proposed by numerous states and determine whether they could be used as the basis forcalculating MTCA Methods B and C risk-based cleanup levels. The Interim TpH policy is
intended to be consistent with existing MTCA regulations, and not to change these regulations in
any way.
Methods B and C take all majorpotential exposure pathways into account in setting cleanup
levels- ln the Interim Policy we have provided guidance on only npo of these pathways: (i)
direct human health contact, and (2) soil-to-groundwater. Because of the limiGd availabiity of
information, technical uncertainty, and unresolved issues, this Interim Policy does not
completely address all of the issues related to potential impacts to human health and the
environment from TPH contamination. For instance, this Interim Policy does not completely
address the health effects for occupants of a stnrcture where there is repeated, long-temr expos're
to TPH vapors. Also, this Interim Policy does not provide cleanup levels that address ecological
protection or residual odors from TPH contaminated soils. These issues, and others, will be
evaluated more completely by Ecology and the Duwamish Coalition TPfo Brownfields project
Oversight Group and will, as appropriate, be incorporated into a final TpH policy and/or
amendments to the MTCA regulations. Until then, issues not addressed, or not thoroughly
addressed, by this Interim Policy need to be evaluated on a case-by-case basis using Ulie,
appropriate policies and guidance, and professional judgment.
I
An I4terim Policy was proposed because changes to the Model Toxics Contol Act for Method Acleanup levels, or the way cleanup levels are derived, would require .*;;J;g the regulation.This might not occur until sometime in 1998, while this Interimpolicy is effective immediately.
In June 1996' Ecology invited interested parties to participate in a working group to assist in thedevelopment of the Interim Policy. over a period of approximately five rio-n,t r, the workinggroup met seven times. In addition, various subgroups met to discuss specific topics (toxici!,fate and tansport, analytical issues, and groundwatei beneficial use). Aher the working groupmade its recommendations, Ecology consulted with the Science Advisory Board, the EpA, theWashington Department of Health, and the office of the Attorney General. This Interim TpHPolicy refl ects their recommendations.
The Policy Advisory Committee (PAC) also asked Ecology to evaluate how we implement rulesthat describe the reasons that can be used to demonstate that groundwater at a site is not apotential futue source of drinking water. Because this issue applies to more than TpH, and withthe agreement of others in the workgroup, this groundwater issue witt U. uaar.rr.d separatelyfrom this Interim Policy.
New analytical methods have been developed for this Interim Policy. These methods are beingmade available to the laboratories.
If you have site-specific questions on how to apply this Interim policy, please contact theappropriate regional office. If you have questions about this Interim Foiiry, please contact SteveRobb at (360) 407-7188 in olympi4 or you can contact him by e-mail ut tioi+etgecy.wa.gov.
Questions about the soil-to-groundwater or soil-to-vapor components should be directed to LynnColeman at (360) 407-7194 or e-mail at lcol46l@ecy.wa.gov.
CBK: df
Att.achment
1
Contents
lntroduction and Purpose of lnterim Policy "'..
Background ..........
Surrogate Approach for TPH
Overview..
Human Health Toxicity
Fate and Transport.........
Analytical
Relationship Between This Document and Existing Ecology Guidance'on TPH
Step-by-Step DescriPtibn
Step 1: Remove Active Product Source
Step 2: Conduct lnterim Actions As Needed ....
Step 3: Characterize the Site
Step 4: ldentify Cleanup Levels.'..........
Method B and Method C ....
Vapors and Odors
Human Health ToxicitY
(a) Groundwater
(i) Drinking Water.......
(ii) Nonpotable Groundwater ..
(b) Surface Water
(c) Soil
Carcinogen Formulas and Calculations...
(ii) Soilto Groundwater PathwaY
Option 1: 100 X Groundwater.........'.
Option 2: Soil/Pore Water Partitioning and Mixing
Fate and TransPort Parameters..
Partitioning
Residual Saturation...
Calculations
Option 3: EmPirical Demonstration
Option 4: LUST Matrix.....'.
(iii) Soil to Confined Space lndoor Air P
Step 5: Compare Site Concentrations to Cleanup Levels""""
Step 6: Select and lmplement Cleanup Action (if Appropriate)
Step 6.1: Evaluate Altematives
Step 6.2: Select the Remedy for the Site.......,.'.'.
Step 6.3: lmplement the Remedy..............
Step 6.4: Disposal and End Use Criteria.........'.'.'
Paqe
2
2
3
4
5
5
b
7
7
7
7
II
9
23
24
24
25
25
25
25
26
zo
1
Step 7: Evaluate Cleanup Action..'...26
')
lntroduction and Purpose of lnterim Policy
The Model Toxics ControlAct (MTCA) establishes a process for cleaning up sites that
are contaminated with hazardous substances, including total petroleum hydrocarbons
(TPH). One step in the cleanup process is defining appropriate cleanup levels. MTCA
allows cleanup levels to be set in three different ways, known as Methods A, B, and C.
Method A levels are set by lookup tables, background concentrations, analytical
quantitation limits, and other regulations. Methods B and C levels must be calculated
using formulas in MTCA. Use of the formulas requires certain information about the
contaminants, including toxicity data. Toxicity data is also necessary to determine
levels in one media (such as soil) that will also protect other media (such as air or
water). Because of concern about the absence of adequate toxicity data for TPH, the
Department of Ecology (Ecology) has discouraged the use of Methods B and C for
deriving cleanup levels for TPH. Ecology issued a Focus Sheet in 1994 recommending
that only Method A cleanup levels be used for TPH. This lnterim lnterpretive and Policy
Statement (lnterim Policy) supersedes that Focus Sheet.
Members of the regulated community have asked Ecology to provide guidance on how
valid cleanup levels, other than Method A, may be established for TPH under the
current MTCA regulations. The purpose of this lnterim Policy is to explain how cleanup
levels protective of two primary exposure pathways may be set for TPH using Methods
B and C, and to provide a step-by-step description of the process to be followed.
These pathways include direct human contact with contaminated soil, and soil levels
that will also protect groundwater.
This lnterim Policy is advisory; it is not binding on Ecology or the regulated community.
It does not completely address health effects of vapors, nor does it provide cleanup
levels that necessarily address residual odors or ecological (non-human) receptors.
The statements contained in this document reflect Ecology's interpretation of its existing
regulations. However, this document does not take the place of the regulations, and it
should be read in conjunction with those regulations. Furthermore, nothing in this
document is intended to modify, in any way, MTCA or its implementing regulations.
Future changes to the statute or regulations may affect the statements contained in this
document. Since Ecology anticipates proposing amendments to the MTCA regulations
regarding TPH cleanup levels within the next few years, the reader is cautioned to
watch for such changes.
Backqround
Ecology adopted cleanup standards for MTCA in 1991. Risk-based, site-specific
cleanup methods that protect air, soil, and water were developed. Risk scenarios were
based on residential (Method B), and commercial and industrial exposures (Method C).
3
ln addition, a "routine" method was provided (Method A). Method C (commercial and
industrial) will result in restrictions on the future use of the site.
Cleanup levels for soils established under Methods B and C must meet four
requirements. First, they must be at least as stringent as concentrations established
under applicable state and federal laws, commonly known as "ARARs." Second, they
must not cause contamination of groundwater at levels that exceed groundwater
cleanup levels set under MTCA. Frequentty, this value is established by multiplying the
applicable groundwater cleanup level by 100. However, the regulations allow for a
demonstration to be made that a higher soil concentration will be protective of the
groundwater. For TpH, the regulations expressly allow the demonstration to be made
6n the basis of data on individual substances that compromise the TPH. Third, cleanup
levels for soils established under Methods B and C must not result in acute or chronic
effects on human health via direct contact with contaminated soils. These levels are
calculated using a formula provided in the MTCA regulations. Use of the formulas
requires toxicity data about the hazardous substance of concern. Fourth, cleanup
levels for soils must ensure there will be no exceedances of ambient air concentrations
established under MTCA.
Because of the absence of adequate toxicity data regarding all constituents of
petroleum mixtures Ecology has discouraged the use of Methods B and C to calculate
TpH cleanup levels; Ecology has recommended that only Method A be used.
petroleum products are complex chemical mixtures that consist of hundreds of
compounds. Although good toxicity data exist for some of these compounds, for many
others there is no dJta or is inconclusive. Evaluation of the toxicity of petroleum
,"i""r"J into the environment is further complicated by the fact that the chemical
composition of a release changes over time due to weathering effects and natural
degradation.
ln order to clarify the cleanup process and show how cleanup levels and remedy
selection interact, this lnterim Policy outlines the steps of the remedy selection process
for petroleum release sites-
Surrooate Approach for TPH-Overview
This lnterim policy explains how to calculate Methods B and C cleanup levels for TPH
using surrogates.- The surrogate approach involves representing complex weathered
petrJleum rirtrr", ny suustiiuting'known data for particular substances or for ranges of
substances. since thl whole product mixture at each site can no longer be evaluated,
smaller fractions of the mixture from the site must be evaluated instead. The use of
surrogates is a two-step process: (1) define the fractions, and (2) define the surrogate
values to be used for those fractions'
4
Cleanup levels under MTCA must protect humans from direct exposure to the
hazardous substance, and also must protect other media that may become
contaminated if the substance migrates. ln this lnterim Policy, direct exposure is
referred to as "toxicity,' and the migration of contaminants from soil to other media is
referred to as "fate and transport." For toxicity, the surrogate values needed for
Methods B and C are toxicity oral reference doses (ORfDs). For fate and transport the
surrogate values are the physical and chemical properties that can be used in
mathematical models for chemical movement through and into soil, water, and air.
Fractions of petroleum can be defined by the size of the molecules of the substances.
Since a common analytical technique, chromatography, relies on the mobility of the
substances and mobility is related to the size of the molecules, chromatography can be
used to define and quantiff fractions of the mixtures.
Petroleum compounds have molecular structures based on atoms of carbon. The
shape of the molecules (straight chain, branched chained, cyclic, etc.) and the size
(number of carbon atoms) determine the chemical and physical properties. The
relationship between the structure and the chemical and physical properties can also be
expressed by how many carbons each substance acts as if it has rather than how many
it actually has. This will better allow groups of substances, or'fractions" (fractions of
the total), to be combined with similar-acting substances. The fractions used in this
lnterim Policy for fate and transport use the term "EC" ("equivalent carbons," also called
"relative carbon index numbe/') which is nof always the sarne as actual carbon
numbers. The analytical data must be reported in this manner in order to use the
formulas in this lnterim Policy.
Petroleum hydrocarbons can be divided into two major fractions based on their
structures: (1) aliphatic hydrocarbons (carbon chains that are straight such as normal
hexane, branched such as 3-ethyl hexane, or cyclic such as cyclohexane); and (2)
aromatic hydrocarbons (typified by benzene-unsaturated 6 carbon ring-structures).
The two fractions tend to have similar compounds within each, both in terms of toxicity
and fate and transport properties. Hydrocarbons can have single carbon-to-carbon
bonds (alkanes); one or more double carbon-to-carbon bonds (alkenes); or one or more
triple carbon-to-carbon bonds (alkynes). Alkynes are rare in petroleum products. Since
it is easier from an analytical perspective to include most alkenes with aromatics and
they share many properties, the term "aromatics" in this lnterim Policy is meant to
include alkenes (some alkenes, especially volatile low carbon number alkenes may be
quantified as aliphatics rather than as aromatics).
Surrogate Approach for TPH-Human Health Toxicity
It has not yet been demonstrated to Ecology that there is adequate data to support
more than one surrogate substance with a corresponding oral reference dose (ORfD)
for each of the two groups, aliphatic and aromatic. Therefore, only n-hexane, as the
5
surrogate for the entire aliphatic group, and pyrene, as the surrogate for the entire
aromitic group, are discussed. The oral reference doses for these two substances are
atready established and used in MTCA.
An important principle in MTCA for toxicity (non-carcinogen) determinations is
"additivity.' That is, toxic effects can be the sum of everything that produces the toxic
effect. For purposes of calculating Methods B and C cleanup levels, differing toxic
effects do not need to be added together, but similar effects must be added together.r
All the toxic effects of all the petroleum compounds are not known, and defining them
for fractions has not yet been accomplished to Ecology's satisfaction. At this time,
Ecology assumes toxic effects can be the result of aliphatics, aromatics, or any fraction
thereoi Therefore, as described in the MTCA regulation, they must be summed and
the sum cannot exceed a hazard index of "one."z
Surrogate Approach for TPH-Fate and Transport
This lnterim policy also proposes a way to use surrogates to model the fate and
transport of petroieum. The use of fractions and surrogates is well suited to a complex
mixture such as petroleum. The broad range of physical properties of the compounds
in a mixture can be modeled by many fractions. This lnterim Policy recommends six
fractions for aliphatic compounds, benzene and toluene for the smallest aromatic
compounds, and five additional aromatic fractions. There are two fate and transport
pathways of major concern: (1) movement from the soil to groundwater; and (2) from
ihe soil to air. There are numerous models in scientific literature for these pathways,
but most apply to single substances or simple mixtures. The modeling of the complex
petroleum *i*ture is itiil under study, especially for vapor transport. For protection of
groundwater, especially when the groundwater is or.can be a source of drinking water,
i t"te and transport model is suggested that is considered to be protective.
Surroqate Approach for TPH-Analytical
The analytical method is a two-step process: (1) measure volatile petroleum
hydrocarbons (VpH) by a "purge and trap" process followed by gas chromatography
(GC) and detection'UV t*o detectors that can discriminate between many aliphatics and
aromatics; and (2) measure extractable petroleum hydrocarbons (EPH) by a solvent
extraction and solid-phase extraction/fractionation followed by gas chromatography and
a single detector. The distinction between aliphatics and aromatics for EPH occurs in
the extraction stePs.
lFor instsance, each compound affecting the nervous syslem should be added
tsogether, but, they do not need !o be added with compounds thaE affect only the
Iiver
zwac 123-340-700 (3) (b) a (c)
6
ln addition, individual substances must be analyzed in many instances: benzene,
ethylbenzene, toluene, xylenes (BETX), carcinogenic polynuclear aromatic compounds(cPAHs),:and possibly other hazardous substances such as fuel additives that may
occur with petroleum products.
Current "W-TPH" (Washington methods for TPH) analytical methods may still be used
for screening samples or for Method A.
on TP
ln 1991, Ecology issued a guidance document for remediation of petroleum
contaminated soils for leaking underground storage tanks. ln 1994 the document was
updated and its focus was changed so that it was no longer aimed at leaking tanks
That guidance document, entitled
Contaminated Soils remains valid However, it should be read in conjunction with this
lnterim Policy which describes how Methods B and C cleanup levels may be calcutated
for TPH. For example, Table V (End Use Criteria For Petroleum Contaminated Soils) of
the Guidance for Remediation of leum Contamin ated Soils is based on Method A.
This lnterim Policy permits the development of cleanup levels that are risk-based and
site-specific. This lnterim Policy may be used to modify Table V values of the Guidance
for Remediation of Petroleum Contaminated Soils to reflect Methods B or C values
appropriate for the disposal location or end use.
ln 1992, Ecology issued a document entitled: Petroleum Contaminated Soils Rating
Matrix to provide guidance on circumstances in which TPH concentrations in soils could
exceed Method A levels without harming a drinking water aquifer. However, an upper
limit could not be determined for toxicity, so the guidance was limited. The Matrix can
still be used for example, when the TPH contamination is low and guidance is needed
on how to do a TPH analysis, as for Method A.
ln 1994, Ecology issued a "Focus" sheet entitled: Total Petroleum Hvdrocarbon (TpH)
Cleanup. ln the "Focus" Ecology stated, "Methods B or C can be used for contaminants
that are on-site along with TPH, but TPH cleanup levels must be defined by Method A
or the LUST Matrix." This lnterim Policy replaces that Focus document
ln 1995, Ecology issued Guidance on Samplinq and Data Analysis Methods to provide
information on common sampling and data analyses issues. The document is
Publication No. 9449. This Guidance is still recommended.
3The list, of the 7 compound.s is found in wAC L73-340-200 under the definitsj-onfor I'PAHs (carcinogenic) ". They are also listed laEer in this documenE in thet,able for TPH compounds.
7
Step-by-Step Description
Following is a step-by-step description of how a petroleum release may be addressed
under MTCA:
Step 1: Remove Active Product Source
lf the removal of a tank or other active product source is already planned or undenruay
at the site, remove heavily contaminated soil as part of the project. (ln areas with a
high water table, conduct the project during periods of low groundwater levels, if
possible, to allow removal of any heavily contaminated "smear zone" soil.) The heavily
contaminated soil should be treated or disposed of at a fully permitted facility that is
authorized to accept such material. The decision whether to treat or dispose of the
contaminated soil should be made in accordance with the remedy selection
requirements of WAC f73-340-360.
Step 2: Conduct lnterim Actions As Needed
Where an interim action is appropriate, it should focus on stopping free product or
vapor migration. The goal is to eliminate or minimize migration beyond the property
boundary or point of actual exposure, whichever is closest to the source. Eliminate
explosion hazards and immediate inhalation risks, remove free product in the tank pit,
stop any obviously on-going product releases, migration, et cetera. See WAC 173-340-
430 for interim action requirements.
Step 3: Characterize the Site
Site characterization should be commensurate with the site conditions and complexity.
Enough data must be collected to complete the site characterization. These may be
done all at once or in phases (i.e., enough data are collected to select the next action,
then additional data are collected as the need arises). See WAC 173-340-350 and 450
for requirements related to remedial investigation and feasibility studies.
Table 1 shows TPH compounds and TPH fractions that could be found in releases; use
it as a guide for analysis. However, it cannot be taken as a complete list. Caution
should-be used, especially when the type of release is uncertain, when there may be
contaminants, or when the release may contain more than one product-
B
Table 1
TPH Compounds and TPH Fractions
Type of
Release
TPH Compounds
and TPH
Fractions
Gasoline Kerosene,
Jet fuels
Diesel,
Light fuel
oils
Heavy fuelr: oils
Unknown
(l)
Benzene X X X
Toluene X x X
Ethylbenzene X X X
Xylenes x X X
: :i,: s inr s ii5 p4 irbljPll*jl*j,
Benzo(a)pyrene X X X X
Chrysene X x X x
D ibenzo(a,h)anthrac ene X X X X
Ideno( 1,2,3-cd)pyrene X X X X
Benzoft)fluoranthene X x X X
Benzo(a)anthracene X X X X
Benzo(b)fluoranthene X X X X
Other PAHs X X X X
(2)(2)
Lead (inorganic)(2)(2)
Ethers (e.g. MTBE)(2)(2)
Ketones (2)(2)
Alcohols (2)(2)
Aliphatics EC5-EC6 X X X X
Aliphatics >EC5-ECt x X x X X
Aliphatics >ECr-EC,o X X X X x
Aliphatics >ECro-ECr2 x X x X
Aliphatics > ECrz-ECr6 x X x
Aliphatics >EC,.X X
Aromatics >EC8-ECro X X x X
Aromatics >ECro-ECr2 X X X X X
Aromatics >EC,2-EC,6 x(3)x X X X
Aromatics )EC,"-EC",x X x x
Aromatics >EC2r-ECrj X X
(1) Wast,e oil could contain halogenated compounds such as trichloroethylene
and PCBs, and hearry metals such as chromium and cadmium(2) When suspecEed to be presenL
9
(3) There are few compounds of this aromaEic fraction
"extended'r vPH method should be adequaEe for this fracti-on
in gasoline. The
10
Step 4: ldentifo Cleanup Levels
cleanup levels are determined by one of three methodsMethod C.
Table 2: MTCA Method A petroleum Cleanup Levels
Method A, Method B, or
Groundwater (pg/L)Soil(mg/kg)
TPH
Gasoline
Diesel
Other
1,000
100.0
200.0
200.0
Benzene 5 0.5
Ethyl benzene 30 20.0
Toluene 40 40.0
Xylenes 20 20.0
J
Method A-Method A cleanup levels may be used at appropriate petroleum releasesites, but they are not mandatory. Method A consists oi lookup tju,r", w1h media-specific TPH cleanup levels, as well as cleanup levels for certain indivioual constituents(9'g'' BETX)' MTCA Method A cleanup levels for TPH and BETX are shown in Table 2(from wAc 173-340-720; 173-340-740: and 17g-340-745). The Method A lookuptables do not provide creanup revers for surface water or air.
Method B and Method c-As noted.earlier, a principal objective of the TpH lnterimPolicy is to explain how petroleum cleanup teu"rr r"y be established using Methods Band c' To do this-, it is.necessary to evaluate the toxicity of a given p"lrot"r1n releaseand the potential for migration. The EPA has developed prouiiionrl'dose-responsevalues and cancer slope factors for some whote prod'ucts (e.g., gasoline). However,these values are for fresh product and do not take into account the changes in theproduct due to weathering and natural degradation; thus, toxicity evaluations based onwhole product values have large uncertainties. These uncertainties may besubstantially reduced by evaluating the toxicity of the diff";;;f;;rb"; n'uro"r fractionsin a mixture' This lnterim Policy describes a way to use these fractions for a surrogateapproach as well as a way to use fractions of TPH for predicting fate and transport toother media.
11
Vaoors and Odors
This lnterim Policy does not completely address health effects of vapors nor does it
provide cleanup levels that necessarily address residual odors.
Human H Ith Toxicitu
For human health toxicity (non-carcinogen), Ecology is recommending two fractions for
TPH: "total aliphatics" and "total aromatics." All petroleum mixtures can be represented
by these two plus the three substances with oral reference doses used in MTCA:
toluene, ethylbenzene, and xylenes (total of the three xylene isomers). The ORfDs for
these fractions and substances are shown in the following section on "Non-Carcinogen
Formulas and Calculations for Human Health Contact-Soils" (see page 12).
Surrogates are used only to evaluate non-carcinogenic effects. They are not used to
evatuate the carcinogenic risk posed by a petroleum release. lnstead, carcinogenic risk
is determined by benzene and, if appropriate, carcinogenic PAHs (cPAHs). The
procedure for evaluating the carcinogenic risks of a petroleum release is the same as
current MTCA practices: benzene, cPAHs, and any other contaminant cannot exceed
their individual Methods B or C carcinogen formula levels for individual or total risk (see
wAc 173-340-720 (3) & (a); fi3-340'-740 (3) & (a); and 173-340-745 (4)).
It is necessary to comply with other non-carcinogen Methods B or C levels or other
regulatory standards such as "Maximum Contaminant Levels" (MCLs) for potable
groundwater even when using BTEX and surrogates for toxicity.
Under MTCA, cleanup levels must be established for each impacted medium.
Moreover, the cleanup level must be set at a levelthat not only is protective in the case
of human direct contact (e.g., ingestion of soil or water), but also accounts for exposure
through other pathways or to environmental receptors (e.9., soil to groundwater, soil to
buildings or subsurface structures, vapor explosion hazards, surface water). ln
considering these other potential impacts, it may be necessary to take into account
considerations other than direct human health contact levels such as chemical
saturation levels.
(a) Groundwater
Cleanup levels for groundwater depend on the highest beneficial use and reasonable
maximum exposure expected to occur under both current and potential future site use
conditions. Under MTCA, it is presumed that the highest beneficial use of groundwater
is its use as drinking water, and that the reasonable maximum exposure occurs through
ingestion and other domestic uses.
t2
(i) Drinking Water
lf the groundwater is a current or potential future source of drinking water, cleanup
levels can be established using the same surrogate approach as described for cleanup
levels for direct contact with soil, applying that approach to the groundwater cleanup
formula provided in WAC 173-340-720. However, the Method A TPH cleanup level of
one milligram per liter for all petroleum hydrocarbons can be used if it is higher than a
formula value.
(ii) Nonpotable Groundwater
lf it is demonstrated that the groundwater is not potable under WAC 173-340-720, then
it is necessary to determine the highest beneficial use. Alternative beneficial uses
include discharge to surface water (and pr,otecting the uses of the surface water
including habitat in both the water and sediments), agricultural uses, industrial uses,
recreational uses, as well as discharge to another aquifer that is a current or potential
future source of drinking water. Once the alternative beneficial use is determined, it is
necessary to establish the cleanup level applicable to that use (e.9., surface water
quality criteria, bioassays, or other criteria may be needed, as appropriate, to establish
surface water cleanup levels).
(b) Surface Water
No adverse impact is allowed on surface water including the uses described above.
Adverse impacts include water quality criteria violations such as a visible oil sheen.
(c) Soil
(i) Direct Contact
The recommended procedure for establishing a cleanup level for direct contact with soil
is shown in the Toxicity Worksheet (Table 3, page 13). Hazard quotients are
calculated for each TPH fraction-aliphatics and aromatics. The Ecology analytical
method for total aromatics includes ethylbenzene and xylenes but not benzene and
toluene, so benzene must be added (there is not an ORfD for benzene so the benzene
concentration must be added to the aromatic fraction rather than calculating its toxicity
separately) and ethylbenzene and xylenes subtracted and calculated separately (see
13
following formulas). + Hazard quotients should also be determined for toluene,
ethylbenzun", "nd total xylenes. The hazard quotients then must be added. lf the sum
(the hazard index) is greater than 1.0, the direct contact levels are too high and must be
lowered. They can be lowered through several methods. Ecology has no preference
as to a method. The totalTPH can be reduced, or individual fractions or substances
can be reduced. The resulting concentrations must be compared to the concentrations
derived to protect other media, and the lowest protective numbers must be used.
Non-Ca nooenic Fo ulas and Calcu tions for Hu n Health C ls
For Residential Soils:
soil concentration(SC)-ppm = (oRfDXABW=1 6 kqXUCF2=1,000.000 mq/kqxHQ)
(SlR=200 mg/kgXABl =1 XFOC=1 )
or:
HQ=(SC-oomX20 0 mo/koX1X 1)
(ORfDXl 6 kgx1,000,000 mg/kg)
Hazard Q u otie nt = (S o i I Co n ce ntratio n-p p m) ("facto /')/O RfD
FactoriORfD = "multiplier"
Residential Factor = 20Ah6,000,000 = 1.25 x 10e-5
Commercial Soils Factor = 3.125x 10e-6
lndustrial Soils Factor = 2-86 x 10e-7
aThe fractsions and formulas used for toxicity are nou the same as for faEe and
EransporE, so analytical resultss cannoE be used wiEhouts manipulatsion for aE
least one seE of the calculations '
L4
Oral Reference Dose (ORfD)s
TotalAliphatic = 0.06 mg/kg-day
TotalAromatic (5'EC" fractions plus benzene)s - 0.03 mg/kg-day
Ethylbenzene = 0.1 mg/kg-day
Toluene = 0.2 mg/kg-day
Total Xylenes = 2.0 mg/kg-day
EXAMPLE
ln the following Table, example soil concentrations have been selected to illustrate howone determines the hazard quotients and hazard index. ln this example, no hazardquotient or hazard index exceeds "one" so these levels would be considered to beprotective for human health contact toxicity (non-carcinogen) under this surrogate
approach.
(The term "Factor" is the number representing all the values of the formula other thanthe ORfD; the term "Multiplie/' is the number representing the "Factor" divided by the
ORfD for the compound. The soil concentration times the multiplier results in the
hazard quotient.)
Table 3: Example Worksheet
Non-Carcinogen--Human Health Soils Contact
soRfDs are subjec! to upd.ating. check with Ecology if uncert,ain.6"Tota1 aromatics" should not include ethylbenzene, toluene, and xylenes sincethey are comput,ed separaEely. The Ecology analyEical method for aromaticsincludes ethylbenzene and xylenes in the result for the EC>B-10 fraction.
"Total aromat,ics" is uhe sum of t,he 5 fractions, so those compounds slrould besubEracted. Benzene is not included in any of lhe I'ECrr fracEions, so it mustbe added to account for its cont,ribution.
15
Compound
Soil
Conc.
(ppm)
Residen.
Factor Multiplier HQ
Commer.
Multiplier HQFactor
lndus.
Factor Multiplie HQORfD
Totalaliphatic
Total aromatic
Benzene
Ethylbenzene
Toluene
Xylenes
Total aromatic+B-E-X
3000
1200
20
200
s00
500
520
0.06
0.03
0.10
o.20
2.00
0.03
1.258-04 2.08E-03 0.63
1.25E-04
1.25E-04
1.25E-04
1.25E-U
1.25E-03
6.25E-04
6.25E-05
4.17E-03
0.03
0.03
0.00
0.22
3.13E-M
1.56E-04
1.56E-05
1.04E-03
0.00
0.00
0.00
0.05
3.125E-05 5.21E-04 0.16
3.125E-05
3.125E-05
3.125E-05
3.125E-05
0.00
0.00
0.00
0.00
2.86E-06 4.77E-05 0.01
2.86E-06
2.86E-06
2.86E-06
2.86E-06
2.86E-05
1.43E-05
1.43E-06
9.53E-05
,:"i:i$!$*H3-2.!rgr!1"{eX irf: ,;..rr,*lss**.$R**;i.':Is\iYi: itiiiP:so .$-iii'. ri.s:..,i,s" .,-,:i:: "::';t i;::l*i0.23 $ii.i\j!:ir$.ji;.\,', r. 0.02
Carcinoqen Formulas and Galculations for Human Hea Ith Contact--Soils
For Residential Soils
Soil Concentration-ppm =
(OCP FXS I R=200 mg/day)(AB 1 = 1 XDU R=6 yrs)(FOC= 1 )
or:
Risk = €C-ppm) (OCPfl (200 mg/dayX1)(6 yrsXl)
(16 kgx75 yrsxl ,000,000 mg/kg)
Risk = (SC--ppmXOCPFXl x 106)
Commercial Soils: Risk = (SC-ppmXOCPFX2.5 x 10'?)
lndustrial Soils: Risk = (SC-ppmXOCPFX7.62 x 10{)
Oral Cancer Potency Factor (OCPflz
?OCPFs are subjecE to updating. Check vrith Ecology Lf uncertain
ife=7 U
L5
Benzene = 0.029 kg-day/mg
Carcinogenic PAHs (all) = 7.3 kg-day/mg
L7
(ii) Soil-to-Groundwater Pathway
An evaluation of the soil-to-groundwater pathway determines what concentrations may
be left in vadose zone soil and not cause an exceedance of groundwater cleanup
levels. Under Method B, this cleanup level is established by multiplying the applicable
groundwater cleanup level by 100 (Option 1 below), unless it can be demonstrated that
I nign"r soit conceniration is protective of groundwater (WAC 173-340-740(3)(a)(iixA)).
OptLns 2 - 4 are given below as suggested ways to make the demonstration allowed in
the rule in order to deviate from the 100x method. These options may be used to
calculate vadose zone soil concentrations protective of groundwater unless the release
of hydrocarbons in soil has already reached groundwater and the groundwater cleanup
leveis are exceeded at the point of compliance, or the assumptions inherent in the
options are not appropriate for the site (i.e. use of the options would tend to
underestimate the migration of the chemical in the environment). lf groundwater
cleanup levels have blen exceeded, a remedial action should be selected. These
calculations will also be useful in selecting remedial actions and focusing efforts on the
material/situations presenting the greatest risk to groundwater.
Other options to develop cleanup levels may be proposed to Ecology on a site-specific
basis. Also, the theoreiical and empirical methods presented here may be refined or
new methods added as Ecology continues work on the issue of fate and transport.
Option 1: 100 X Groundwater
The Method B approach given in the rule may still be used. That is, the soil cleanup
level protective oi groundwater may be established by multiplying the applicable
groundwater cleanirp level by 100. Groundwater units of mg/l convert directly to soil
inits of mg/kg after multiplying by 100. For example: where the Method A drinking
water concentration of t m-gdis ihe "ppropriate
cleanup level, 100 times 1 mg/L would
equal a soil cteanup level of 100 mg/kg.
Option 2: Soil/Pore Water Partitioning and Groundwater Mixing
Equilibrium partitioning in the vadose zone and a simple mass balance mixing model in
the saturated zone mJy oe used to estimate soil concentrations that are protective of
groundwater. Use of these two concepts is based on the following simplifying
assumptions:
. Soil contamination extends from the surface to the water table;
o The source is infinite (i.e., steady-state concentrations will be maintained
ingroundwaterovertheexposureperiodofinterest);. Contaminants are uniformly distributed throughout the zone of
contamination;
18
' There is no chemical or biological degradation in the unsaturated zone;' Fquilibrium soil/water partitioning is instantaneous and linear in thecontaminated soil;
' The receptor well is at the edge of the source (i.e., there is no dilutionfrom recharge downgradient of the site) and is screened within the plume;. The aquifer is unconsolidated and unconfined (surficial);. Aquifer properties are homogeneous and isotropic; and
' There is no attenuation (i.e., adsorption or degradation) of contaminants inthe aquifer.
Under this approach, two fate and transport mechanisms are accounted for: (1) vadosezone partitioning between the contamination in the soil and the water "leachatei flowingthrough that contamination source, and (2) mixing of contaminated "leachate" from thJsource and clean water in the saturated zone.
Fate and Transport Parameters
Part of the difficulty in conducting fate and transport modeling for TpH has been that itis a mixture of many chemicals, and the values for various ptiysical and chemicalproperties of petroleum distillates vary widely. These physicai and chemical properties
are input variables for the different fate and transport equations/models used toevaluate chemicals' movement in the subsurface. \Mthout estimates of theseproperties, it has been impossible to evaluate TPH as a whole, and efforts have beenlimited to use of indicator chemicals such as BTEX.
Recently, work has been done to estimate these physical and chemical properties bysplitting TPH into smaller'slices" or fractions. Properties such as solubiiity, Henry,sConstant, or molecular weight of each fraction, have been estimated by looking ai whatdata are available for the compounds in each fraction and assuming that similjr
compounds would have similar properties. Ecology has reviewed two different
schemes for establishing fractions and the corresponding physical and chemicalparameters for those fractions (e.9., solubility or molecular weight). Currenfly, Ecologybelieves that the work done by the nationalTotal Petroleum Hydrocarbon CriteriaWorking Group (TPHCWG) provides the most accurate estimate of these parameters.
The work done by the state of Massachusetts was arso reviewed.
Fate and transport parameters from the TPHCWG are presented below. These values(from the October 8, 1996 final draft of Selection of Representative TpH Fractions
Based on Fate and Transport Considerationst may be used unless intormation isavailable indicating that other values are appropriate for a particular mixture. The
TPHCWG has not yet completed lab or field validation of these theoretically calculatednumbers. As more experience with these theoreticalvalues and the surrogate
approach is gained, there may be modifications.
19
20
Table 4
Fate and Transport Fractions and Surrogate Values
* EC - Equivalent carbon number
"* Koc - Octanol/water partition coefficient
Partitioninq
Below are two theoretical equations that can be used to determine partitioning (of
dissolved phase) to pore water in the vadose zone. The two equations are: Raoult's
Law and a three-phase equilibrium partitioning equation. \l/hen certain chemical
mixtures, such as TPH, are present or when chemicals exceed the chemical saturation
level, Raoult's Law governs the concentrations of chemical(s) in the vapor and water
phases of the soil. Raoult's Law states that the equilibrium concentration of a chemical
in the moisture phase is dependent on the mole fraction and the solubility of the
chemical in water. That is, the composition and solubilitv of the fractions determine the
pore water concentration rather than TPH concentration in the soil. Raoult's Law will
probably be the equation most commonly used for determining soil pore water
concentrations at TPH sites because TPH is a mixture rather than a single compound.
COMPOUND EC*Water
Solubility
Mol.
WT
Henry's
Constant
Koc*
(mg/l)(s/mol)(cc/cc)(Ukg)
ALIPHATICS
EC5-6 5.5 2.6Qf+01 81.0 3.4E+01 7.94E+02
EC>6-8 7.0 4.20E+00 100.0 5.1E+Ot 3.98E+03
EC>8-10 9.0 3.30E-01 130.0 8.2E+0t 3.16E+04
EC>10-12 1 1.0 2.60E-02 160.0 1.30+02 2.51E+05
EC > 12-16 14.0 5.90E-04 200.0 5.4E+A2 5.01E+06
EC > 16-21 19.0 1.00E-06 270.0 6.4E+03 1.00E+09
AROMATICS
Benzene (EC 5-7)6.5 1.8E+03 78.0 2.3E-01 7.94E+01
Toluene (EC >7-8)7.6 5.2E+02 92.0 2.7E-01 2.51E+02
EC>8-10 9.0 6.5E+01 120.0 4.9E-01 1.59f+03
EC>10-12 11.0 2.5E+01 130.0 1.4E-01 2.51E+03
EC > 12- 16 14.0 5.8E+00 150.0 5.4E-02 5.01E+03
EC > 16 -21 19.0 5.1E-01 190.0 1.3E-02 1.58E+04
EC > 21 -35 28.0 6.6E-03 240.0 6.8E-04 1.26E+05
2L
ln order to determine if the soil is protective of groundwater, the calculation starts with
the soil fraction concentrations, calculates a corresponding pore water concentration for
each fraction based on Raoult's Law, allows a dilution factor in the saturated zone, and
compares the diluted pore water concentrations to the groundwater cleanup level to
determine if the TpH composition is protective of groundwater. The equation for
applying Raoult's Law to groundwater is below'
Co* = XS
where: Co*=concentration in the vadose zone pore water, i.e',
effective solubility for each fraction (mg/L)
X = mole fraction of each fraction in the soil
^S = solubility of each fraction in water (mg/L)
This approach assumes: (1) partitioning between non-aqueous phase liquid (NAPL)
and the pore water controls the concentration of chemical in the pore water; and (2) the
fractional composition of the NAPL is the same as the fractional composition of total soil
sampte. TH|S AppRoAcH SHOULD BE USED FOR StrES UNLESS THERE ARE
LOW TPH CONCENTRATIONS AND ONLY A SINGLE FRACTION PRESENT.
For soilwith low concentrations and only a sing le chemical or fraction present, a three
phase partitio ning equation will more accurately predict the pore water concentration
\Mile this equation will probablY not be common ly used, it is presented along with some
background information for those situations where it will be appropriate. "Low
concentrations"in soil are defined as those less than the chemical saturation
concentration (Csat)in the soil. Csat corresPonds to the chemical concentration in soil
at which sorption lim its of the soil Particles,solubility limits of the soil Pore water, and
saturation of soil Pore air, have been reached At these low concentrations. the
concentration in the soil. The equation to determine Csat is below.
c'ot = ]{*"'f"" Pt * o * + H o')
where:
C,"t = chemical saturation concentration (mg/kg)
5 = water solubility of the fraction (mg/L)(see Table-4 above)
pr = du bulk density (kg/Lxsuggested default is 1.85 kg/L for subsurface soils)
'io, = rbil orgrnic carbon /water partition coefficient (Ukg)(see Table 4 above)
f:: = fraction organic carbon in soil (g/gxsuggested default is 0'001)
"0"* = water-filled soil porosity (l-,.*/L*ir)(suggested default is 0'15)
i= Henry's constant (cm3/cm3) (see Table 4 above)
22
0" = air-filled soil porosity (n - 0,)(L./L.oir)(suggested default vatue is 0.1s)n = total soil porosity; (1 - (po /a )xsuggested defautt is 0.30)p" = soil particle density (kg/Lxsuggested defautt is 2.65 kglLi
The recommended default value for fn is 0.1% based on a preliminary review of soildata from Washington State. other numbers for all default values pv o" proposed toEcology on a site-specific basis.
Ile lollowing C,", concentrations are calculated based on the C.", equation with theTPHCWG values (from Table 4) for solubility, Henry's constant,ind Ko"values for eachfraction.
Table 5
Csat: Chemical Saturation Concentration
COMPOUND C""t
(ms/kg)
ALIPHATICSEC 5- 6
EC> 6- 8
EC> g-10
EC> 10-12
EC> 12-16
EC > 16 -21
AROMATICS
Benzene (EC 5-7)
Toluene (EC >7-8)
EC> g-10
EC>10-12
EC > 12- 16
EC > 16-21
EC > 21 -35
319
182
111
65
30
8
1
102
34
13
7
3
1
23
I rl: -t
Below is the three-phase equilibrium partitioning equation. This is Equation 10 on
page 29 of EPA's "Soil Screening Guidance: Users' Guide " (April 1996) with a dilution
factor added. Use of this equation allows direct calculation of a soil level that is
protective of groundwater if the groundwater cleanup level is known. Again, this
equation should be used only for soil concentrations below Csat and where only one
fraction exists.
c" = (c-)(r*Xr,,)*(e. * o,I{)
Pa
where:
C" = soil cleanup level (mg/kg)
C* = groundwater cleanup level (mg/L)
DF - dilution factor
Ko" = soil organic carbon /water partition coefficient (Ukgxsee Table 4)
f"" = lraction organic carbon in soil (g/gxsuggested default is 0'001)
9* = water-filled soil porositY (L*""/L,o,')(suggested default is 0.15)
If = Henry's constant (cm3/cm3)(see Table 4)
0, = air-frlled soil porosity (n - g- XL",/L*i, )(suggested default value is 0.'15)
n = total soil porosity; (1 - (po la ))(suggested default is 0.30)
h = dry bulk density (kg/L)(suggested default is 1.85 kg/L for subsurface soils)
p, = soil particle density (kg/L)(suggested default is 2.65 kg/L)
Residual Saturation
The upper limit to any pore water partitioning equation is when the soil becomes
physically saturated with NAPL such that the NAPL liquid begins to flow downward
under the force of gravity. This concentration is termed "residual saturation". This
concentration is dependent on product properties and soil properties (including grain
size and soil moisture content). Typical literature estimates of petroleum residual
saturation for the vadose zone vary from 10 to 20o/o of the pore space (values reported
range from 5 to 60%). This translates to gasoline concentrations of approximately
IZ,OOO to 24,000 mg/kg (assuming a porosity of 3Ao/o and gasoline specific gravity of
0.7). The value woulO increase to 39,000 mg/kg if porosity were as high as 43% such
as might be found in surficial, non-compacted soil. Values can be higher or lower for
other distiltates and different soittypes or stratigraphy. lf petroleum is in the soil above
residual saturation foi that product type and soil. product will begin to flow downward
purely under the force of gravity. This is a different transport mechanism than pore
24
water partitioning and may cause an exceedance of groundwater cleanup levels if liquid
product reaches the groundwater table.
A site-specific determination of residual saturation for different petroleum distillates and
soil types could be done by reviewing literature sources or conducting lab testing to
estimate the concentration for the soil type(s), soil moisture condition(s), and product
type(s) at the site. Having an accurate, site-specific estimate of residual saturation
would be important for those situations where residual product is close to the
groundwater table, the leak or spill is relatively recent and product may still be slowly
draining downward, there is a high likelihood of an additional product release, or other
circumstances indicate that this is a likely transport mechanism for moving product to
the groundwater.
Calculations
The steps for using the equilibrium partitioning and mixing zone approach when
mixtures are present are below.
Step (a): Calculate partitioning from the soil to the pore water in the vadose zone
Step (b): Determine the dilution factor for the saturated zone.
Step (c): Calculate the projected concentration in monitoring well.
Step (a): Calculate partitioning from the soil to the pore water in the vadose zone for
each fraction.
As described above, Raoult's Law should be used for most TPH calculations to
determine if groundwater is protected.
Co* = XS
wherel Co* = concentration in the vadose zone pore water, i.e.,
effective solubility for each fraction (mg/L)
X = mole fraction of each fraction in the soil
S = solubility of each fraction in water (mg/L)
This approach assumes: (1) partitioning between the NAPL and the pore water
controls the concentration of chemical in the pore water, and (2) the fractional
composition of the NAPL is the same as the fractional composition of total soil sample
Step (b): Calculate the dilution factor for each fraction
25
lf the source area (i.e., area of contaminated material in the vadose zone) is less than
0.5 acre in size, water from precipitation is the only source of infiltration to the
subsurface (e.g., no stormwater ponds or leaking/broken pipelines) and there is no
upgradient contamination flowing into the site, a default value of 20 may be used as the
oitution factor. This value is based on work done by the EPA and is documented in the
G nd
lf the source area is greater than 0.5 acre in size, there is infiltration other than
precipitation or there is upgradient contamination flowing into the site; other methods
must be used to derive the dilution factor. The EPA Soil Screening Guidance:
Technical Backqround Document provides an approach that can be used in these
"ircrrrt"""* (iee text starting on page 42). Ecology is currently evaluating the EPA
method to derive the dilution factor, and plans to provide additional guidance'
Step (c): Calculate projeqted concentration in monitoring well.
For each fraction, divide the pore water concentration calculated in the first step by the
dilution factor to obtain the concentration in groundwater at a well downgradient of the
contaminant source. Then sum the water concentrations for each fraction. This total
number can be compared to Method A drinking water value (if drinking water has been
) O.termined to be the highest beneficial use of the groundwater) and used to evaluate
whgther or not the soil is protective of drinking water. lf the calculated groundwater
number is greater than 1 mg/l, the soil concentrations are not protective of groundwater
lf the calcuiated groundwater number is less than 1 mg/!, the soil TPH concentration
should be protective of drinking water'
Example
The following is an example of the soil to groundwater calculation using Raoult's Law.
Column 1 shows the different aliphatic and aromatic fractions'
Column 2 shows the soil concentrations in each fraction for a hypothetical soil sample.
Column 3 shows the molecular weight of each fraction (from the TPHCWG values).
Column 4 shows the number of moles of each fraction (Column 2 divided by Column 3)
Column S shows the mole fraction of each fraction (each row in Column 4 divided by
the sum of Column 4).
Column 6 shows the solubility of each fraction (from the TPHCWG values).
Column 7 shows the effective solubility of each fraction in the pore water (Column 5
multiplied bY Column 6).
Column g shows the dilution factor (the value of 20 is presented here for the purposes
of illustration only - the dilution factor should be determined according to the
procedures given in the text).
26
Column 9 shows the concentration of each fraction that would be in a monitoring well at
the downgradient edge of the source area. The sum of these values (shown in
bold at the bottom of the column - 3.8 mg/L in this example) should be
compared with the appropriate groundwater standard.
This hypothetical soil example would not be protective of the Method A drinking water
standard of 1 mg/L since 3.8 mg/l is greater than 1 mg/L.
Table 6
Hypothetical Soil-to-Grou ndwater Exam ple
1
GOMPOUND
Aliphatics
EC5-6
EC>6-8
EC >8 -10
EC >10 -12
EC >12 -16
EC >16 -21
Aromatics
Benzene
Toluene
EC>8-10
EC >10 - 12
EC >12 - 16
EC >16 - 21
EC >21 - 35
2345678Soil MW Moles Mol. Frac. Solubility Effect. Sol. DF
(mg/kg) (g/mol) (mmoUkg) (percent) (mg/t) (mg/t)
9
Gonc.@
well
(mg/l)
0.036
0.087
0.0026
0.00002
0.00000
0.000000
100
2000
1000
100
5
5
0.03
0.41
0.16
0.01
0.00
0.00
0.03
0.02
0.17
0.16
0.01
0.00
0.00
1.00
81
100
130
160
200
270
1.2
20.0
7.7
0.6
0.0
0.0
28 0.7 204.2 1.73 200.33 0.052 200.026 0.0003 20
0.00059 0.00000 20
0.0000010 0.0000000 20
100
100
1 000
1 000
50
10
10
78
92
120
130
150
190
240
1.3
1.1
8.3
7.7
0.3
0.1
0.0
48.4
1780
520
65
25
5.80
0.51
0.01
2.36
0.584
0.559
0.1 99
0.002
0.0000
0.0000
47.1 2011.7 2011.2 2A4.0 200.04 200.001 20
0.00001 4
3.8
lf the highest beneficial use of the groundwater is determined to be something other
than drinking water (e.9., surface water), it is necessary to use cleanup levels
applicable to that beneficial use in calculating soil cleanup levels protective of
groundwater.
Option 3: Empirical Demonstration
Alternatively, the pore water concentrations may be estimated by using a leach test
instead of the soil/water partitioning equations. The leach test should be designed to
accomplish the following goals:
27
1) Determine the actual pore water concentration coming from contaminated
material, not a diluted concentration;
2) Model desorption rather than sorption;
3) Prevent biodegradation both prior to and during leach testing;
4) Prevent volatilization during sampling, sample storage/transporting and
leach testing;
5) Address variabilig in soil characteristics and product composition; and
6) Complete a mass balance by measuring fraction concentrations both in water
and in the soil or NAPL Phase.
Ecology is evaluating various protocols to provide specific guidance on this topic. This
type ol testing may also be used on a site-specific basis to confirm the theoretical
values calculated using the partitioning equations in Option 2.
Option 4: LUST Matrix
The existing Leaking Underground Storage Tank (LUST) matrix may be used to
determine soil cleanup levels protective of groundwater if the conditions specified in the
guidance apply to the site.
(iii) Soil to Confined Space lndoor Air Pathway
lf there are surface or subsurface structures that may be affected by vapors from a
residual hydrocarbon source and the residual hydrocarbon includes volatile
constituents, cleanup levels must be established that address both short-term and long-
term risks, as approPriate.
Short-term risks may exist where there is periodic short-term worker exposure (e.9.,
utility maintenance). The risks may relate to the vapor's potential for explosivity or
flammability, as well as toxicity. lf such short-term risks are suspected to exist, the air
inside the structure should be measured (1) for the threshold limit values (TLV) by using
an appropriate detector, and (2) for explosivity and flammability by using a combustible
gas indicator. Alternatively, soil gas sampling may be used to assess the presence of
i"porr in the soil outside the structure. lt should be recognized that vapor migration is
highly variable and soil vapor measurements should be made at times and locations
when concentrations would be greatest: e.g., during times of barometric pressure
changes or water table increases-single measurements cannot be relied on' lf
me"surements indicate that the concentrations pose a risk, a cleanup action must be
selected and implemented under Step 6.
Long-term vapor risks may exist where occupants of the structure have repeated, long-
term exposure (e.g., a full residential basement). Additional work to specity a method to
2A
predict soil concentrations which will be protective of this pathway is underway.
Methods available at this time to monitor for vapor concerns include: soil gas
monitoring as described above, building vapor monitoring, or soil sampling and
analyses. The evaluation of the vapor pathway should include consideration of the
volatile fractions present at the site and/or an indicator chemical approach such as that
provided in the Arherican Society for Testing and Materials - Risk-Based Corrective
Action (ASTM-RBCA) standard. lt should be noted that the RBCA vapor equations only
account for slow diffusion of vapors and do not account for advective flow which can be
a primary transport mechanism. ASTM provides soil screening levels for BTEX,
naphthalene, and benzo(a)pyrene. There may be other volatiles which pose a risk via
vapors.
STEP 5: Compare Site Concentrations to Cleanup Levels
The media-specific cleanup levels determined under Step 4 are compared to the
corresponding concentrations found at the site. lf the concentrations at the site do not
exceed the cleanup levels, no further action is required at the site (other than any
appropriate long-term monitoring), assuming that all appropriate pathways have been
addressed. Otherwise, it is necessary to select and implement a cleanup action under
Step 6.
STEP 6: Select and lmplement Cleanup Action (lf Appropriate)
A cleanup action must protect human health and the environment and be "permanent to
the maximum extent practicable". These and other requirements for selectiqg a remedy
are given in WAC 173-340-360.
Step 6.1: Evaluate Alternatives
ln accordance with WAC 173-340-360, evaluate alternative remedial actions. Common
technologies for petroleum contaminated sites include: soil vapor extraction, thermal
desorption, bioremediation, groundwater pump-and-treat, air sparging, landfilling, etc.
The following types of technologies shall be considered in order of descending
preference: reuse or recycling, destruction or detoxification, separation or volume
reduction, immobilization, disposal at an engineered facility, isolation or containment,
and institutional controls/monitoring.
Step 6.2: Select the Remedy for the Site
Ecology expects that a combination of methods will often be used. For example, in-situ
treatment or removal of material that is migrating and/or material causing the greatest
29
;l
risk might be used in combination with on-site containment (and associated institutional
controls) for material which is not migrating or posing a risk to human health and the
environment if it is contained.
Step 6.3: lmplement the Remedy
lmplement the remedial action selected for the site. Long-term monitoring and
institutional controls shall be required if on-site disposal, isolation, or containment is the
selected cleanup action for a site or a portion of a site (WAC 173-340-360 (8)). Other
requirements for cleanup actions are given in WAC 173-340400.
Step 6.4: Disposal and End Use Criteria
Cleanup levels for soil are determined based on conditions at a particular site. lf soils
are transported from the site at a later date, the assumption should NOT be made that
the soil concentrations are protective for all purposes. Each situation and soil should
be evaluated as to the appropriateness of using that soil at another location and
whether the soil may cause exceedances of cleanup levels at that location. For
example, a soil concentration that is protective based on human ingestion at a
commercial site may not be protective if placed close to a surface water body.
Table V in the Guidance for Remediation of Petroleum Contaminated Soils.page 38,
presents soil concentrations and recommended uses based on Method A cleanup
levels and protection for all pathways. Soils with concentrations greater than these may
be appropriate if it is demonstrated that all pathways/issues at the new location are
addressed.
Step 7: Evaluate Cleanup Action
Once a cleanup action has been implemented (other than operation and maintenance
and long-term monitoring), the action is evaluated to determine whether it provides the
required protection of human health and the environment. lf it does provide such
protection, no further action is required (except for institutional controls, operation and
maintenance, and other long-term monitoring activities, if required). lf it does not
provide such protection, additional steps must be taken to assure protection. For sites
conducted under an order or consent decree, Ecology is required to review the remedy
at least once every five years.
Compliance monitoring is required for all cleanup actions. ln particular, the soil-to-
groundwater calculations are based on theoretical assumptions; therefore, groundwater
monitoring must be conducted to ensure that the groundwater is, in fact, protected.
Goals of the monitoring are: (1) confirm that cleanup standards and other performance
30
standards (if appropriate) have been attained, and (2) confirm the long-term
effectiveness of actions once cleanup standards and other performance standards (if
appropriate) have been attained. See Ecology's document Guidance on Sampling and
Data Analyses Methods, January 1995; EPA's document Methods for Evaluating the
Attainment of Cleanup Standards - Volume 2: Groundwater, 1992; and WAC 173-340-
410 for additional detail.
1
I ,,,/
31
@ 0or
i"]-,'Li,'gri :,ltoN 1t:' tl F'{r lgi '36 J;(]GEO ENGINEERS
ceoffiEngineers
FAX TRAI\SMITTAL
Coup*nY:
City of Port To*rsend
0186-385-85
Jaluar.v 12, 1998
Additional Remedial E'tcavadon and llrerim TPH Polisi"
8410 - l5'1th Avenue NE
Redmond, Washington 98052
TelePhone: (+25) 861-6000
Fax: ('125) 861'6050
tr'rr Number:
(.360) 385-4290Attentiofl:
JeffRa:rdall
Filc:
Date;
Regnrding:
Totd Pages: 21
comments: Jeff_ we tenrativery have scheduled the additional remcdial cxcavation tg mke place at the PSE'
Keamcy St, site on 1/21l98,.ner.1Y"tu::d:I:li-"" "t'""tt-a
* g"ntJ-tilc pUn stto*iog the'Iocation and
dimension of the pran:ned additionar oor-*io*lii" ffi&;; a;t,h";;il;ffie of iaditional soil removed
ftom thcsc ..*ou"rion. ,iiil;" ;;.;n t0 ana i's .uui, y.r'ar, Th" *;J;tt"n-wi11 not be corrductcd in the rain
W. i"ifl.tff you if the schedr:le changes dus to wcathu'
I arso have i*cluded a copy of our letter report srunrnanzing the rcsurrs of r'c lnterim TPH Policv - MrcA Method
B creanup lever carcurauil.-Ib, thc pcuoleurn ir;ilffi;;il.t""i*a ^,
rrrr *t*. A hard ,opy of ttot lefter including
the laboratory repons t.AnachmenrB) has beenmailed to yon'
PlcasccalltneQo6).72s-1z6?4orBarryLonrbard(206;)224.21t)2ifyouhaveanyquestronsorrcquircadclitiorralinfornarion.
iv pv - City ol port To,rmsond
RECEIVFD
JAN I 3 0gB
luildlng & (omrnumity Bovclcpnonf
DcscriPtionIlatcPages
Sruiltury Report' Interim TPH Policy - tvfTCA N{cthod B Cleanup Level
Cllculatiott
Remedial ExcavabonAdditionalof PlannedLocationsGeneral Site Plan ShorryinBu
rl9l98
I
l9
Signed
ldaese@-1 geoen gheers' com
s*#lrdSF1,fccin\lffddrt*r$ Be-cdliof- E .ov"trroSd"d"t{4 {* S".*r. lf\+-\02040l----L- t rScrl-c tN fEErFFlo(oCDtFence-xzPful5,fiJ:rJul€F@t.z c.vllo'TPtIIllIIIA10 412--. -. -'- o .-AFEAAS^14Straet Substolion.a2-'6- 1cto 2. Ecs;-s--ls,-/ c+g*sl* L5* ^.dxr'fxa.5'lsA2IIIAFEAAREA BA1fi,trllrl,2,H'ztllfrln(.l.)$ltcrPt$tAll(}l{:O SOIL s$IPLE T'Y G}1Of:hTLIEERSullllE oF e(cAYAnoH(DtfTHS ARE 1.5' uNLESS oTllERgJlSE l{oTfo)Holc: The locotions ol sll (eollres shotn ore cppror'imote'Refcrcnee" Droring entilled'combincd Doto' concr*l€ Docl At'o' Xeorn?fPort foroserul' Wcbington- b1 Plnnocle GooScicrrcs' undclc{'Nc.lsG*#nq$o*t*REIitEDIAL EXCAVATIONFIOURE 3FORIIERCOI|CREIE DCCKl5
01/13/fi8 )IuN 1{:i0 FA-I {15 861 6050 GEO ENGII{EERS
SummarY RePort
lrrterim TPH PolicY - MTCA Method B
Clearrup Level' Calculation
Petroleum nYOrocarborrs irr Soil
Kearney Street Substation Site
Port Townsend, Washirrgton
January 9, 1998'
.:
For .t
Pulet Sound ErrergY
@oat
(,t\a
3
1
J
GaoEngin€61!Fils No. 0186'385'8i-l t50