Comprehensive Analysis of Indoor Air at Valmont TCE ... · the eastern side of the neighborhood. Air from house 51 'has also contained PCE and 1,1-dichloroethane (1 IDC A).: PCE at

Comprehensive Analysis of Indoor Air at Valmont TCE

Introduction

groundwateB chemicals.were belieyeji to-be; associated with thelOtr^dmateîan^SwiSa^• •' . * " • * , • ' . v, . > ' - - , • > ' , - • . ,, . 4 y *%< ^ ^f '' ''.'""^"^-X- '$' ~t% ^s' -,-1r;'>t

!^r'5{." ''- / -J v^.V^?'3-^-/?^ ' V' V ' ;"/;^<4^^% |-^^,^?xi"/"?'7.7Ax"-"-"'

bât Atfer---!!

ifnmedi|ite êighbdrtooffis:[ajs6,^smili: • • ' ' ' ' • - - ~ .,*" ' ''^--*? ^ , - - ' ~ ^ , . ' i , - ; , , - , , , , A • ' v ' v ' - - ' - v

EPA is currently^conducting a Remediallnyesiigatibn (RI),,tb .-^sSe^tKe^gKMutod^sra1} . >, .; ' .- "r i . - ' s •' '-~ "s-. "<-*;->,'• f;s'-i--fmf^'f-Vy."i^- ."•-• -V"'iff'ft'.';!f!-r~ ••;»i<"^<'w-"t!v3if"^^pJS»|t«sl.faf 'y':|j?contamination that remains. While .tWs'groundsvater is fcurrentlyMbt 1belie,ved|toifci!3s•,j.H-iui.,f '••- ^-i- - -,.-*<.;.^.•&....•., Hwi^«SkvK:^.;%,$j: •^.t4.^fc^v?-4.^îjfefâdhriking water, source, the possibility qf-underground volatilerorganic ehemiealisifpî. :" • --."^ ;;-""."•.••',r v" >.:*;rv- "<•. ^-V5,*»f;|;tf^%^-;ts^..v;'4V«;^'fe»^rmgratmgsmto indoor, airasâ potential^coticerri^For this reasoarm1-— — " i~.~t~.. . - - - s' _ ' - • • ~ * '. .' ' .•"'." .-- '-$".<i";^1-;-/'5*_ji^*'*.> -' •-,.':-;-^f;tfa?.-/~,'collected ~outdoorERA 'Sojijgas, Jesuits .are not^part, of ttus

basement samples*, was obtained %,I?ADE%ifkwfpber~Novefhber qf 200¥^C|fe>ffii... - .p< .^ . i . j- ~:-r-••-, " .-..-- -T * '•'."• * ••-y-fi-ivr1 ~»•?%%<vp(g§>'*$'—2>. «:-•- '•*/-.jf;-ri''.;*,«.-S^"''"^?*' *l»™^SÎconsisting o f basement a n d f i r s t - f l o o r . , s a i n p l e s ' f f l o n i , 2 8 : r e s i d e i i c e s | w 1 '

' * -' " " ' ' ' ' ®" ' ' ~'° ' • "''• " * ' ' * ~r

adyersely imgacting the.ajr inside honies •j&ffie^

At this time, we can analyze the resultstirficomlbinatibn,; t ^ ' - ' r <^J « " , ! , • ' , > * '' , , . * • • ^ ,"-.'• "V . i&s- ^3^ I.t'ig'"^" i, - ?-•

'and extent : fiindoor air conternmants atj,^-^,,, -...y—, , , ,-^(-1.* ^-j jp,-",- i -*-, ,-~ -«r,"~s^' ^~ ';", "i"7iT '" " ''7'."™'"'? "^ *"*'* ?* *"^"^g"H'xr^r~''"j " ~^ *~-fj." - -j-j "-r » _ ' --^

Also; available are sqil gas, data fiofn the PADER: sampling, ambient airi l " . ~ ,- f" "' ' ' "' -• ' *- --" * - Wx,™^- '.' -i-. ;, •;• *~W^!^^*'**t^--<&(^w^^<^M3zaw&S.,^M — s.~.r -^ ,j-,,,G>'.,, i^.-Ri™^- --*K_i,> - ,,.»^

samplmg .results.

EPA peiformfed a.risk assessment of indpprau1 after each of the three 'rojund§| jflihese iaSsessments are referred to throughout this report. Theseaisk assessments;'Ui --•• A / - ' • - . ' • : , . . • - - '. ' ". ' • • '. ,,' ' -'>» '*.'•:• i iE;PA: Superfund default exposures where available; 6-year exposures for cMrdrertiexposures for. adults were evaluated..: Because^ most of the samples w e r e t a l ' '. , • -. ,-- .' - " ' . ' . ' * ' f -.- - . - :- ^24-bour t;){posure to basement air is considere^djto be rather cpriserYatiye. ;

lsa"»" Ip''

REVIEW DRAFT**DO NOT QUOTE OR CITE**page 1

i essmentsta^€Uewith|th|;cjuestion of whether hypothfetic^^sfe:wpxild;be: eeR|4bl|j eveprif •*'"'2', % ' '& f '*V*r~.;r "i'i ''" f id'^S" *", '^^^4'-V»''^X 4--1 "' " t -I*''* '••' f» '-" " "~~ "S* '"vr ^f^ '*•'%*&>*•. <%i* '' - '' "'- '-• ••' '^t^Jt •ir*T^^9i^"f\-"-'''^ ''f-' J*^*!i'*>3lthe residente were exposes for 24 hrs/day, for years. If'these nsls.exceeded EPAiSiSupemind'.-ftv s^& -"s?:,-' ' '3^%^'*<&'$???'"^\f^"^'.- -t^ -"-"] ^ •- .-- ' v* v --;-,'^ '-; ' - //;--.,"* "l^'^^'^y ,'J5 '*'• ?' 1*$" ' W';"' %'"''Cc-~y^ '»f^ '"'-^

j. 'Qr/-^r©v3X

,',i—•v-w- ^?-^rt7-^~^jr^rjS^.T^-^T^^?^T>Jv.-'i'}'< ji * 'S T .,- J J'~ * - "'-••f J ' • • < • < " -j , '. -^ -^ - - - * • • ^ -•- -;•••,,->,- j^'f'J'/- ;\ <? •" ••& . j**t "Si *' v?- J ^ "

•"| epfe l |S'J ; P| i ôgeiKêfee1 ii M«;Sd|ri "i|Ql *|pW3iQi"6x^

|i%ejs|rli||p&l||instM|l lieni e-Refe

'l e iss iiipix&ittg iand;

!^^rs|ss5yT^^7?i7^^^w:^r5V"/i^^ ,-^W'ÎI, ^•-•r^7p;c'.~r •|||<Jnl5^pQ|t, nsfe; |Qwfie^Jevels; .referrea,tp;as^| teniaHjyfefe§gilil>ie,li:€fe^

^^ - - ^ .. ^s- --- jr^r" 5^r"^^"^^^7^T '"?F''-jr?*"~t "v— *r-7* '- -™" ;rvj* "-T ^ tv;-' cr"- ''v*7' ^? " C""'"' F" "" •"" V*" \j " ' ,"^^"^7^~^^^ |P4fel^»£cheim©p,ôn0n]^tip£4^t6eip^^l i i« fe1'n l -i a^ r5«r3^Q*e&'<»tAei?^Tio*>1Se. 1i:er«iindicates

Distribution of Contaminants

Hduse^ were-nu^ê|«d',fr6jn! 15d}M ik 'fwia' alsiloa^-f entîafe Rdad;"arif ^^fifef^^^^^Sl^S^^^^*^j* ">î^,%^ cs -"-• ^r, v>« -^,j -"X * 5 *"* .i«~ • A*' "-v-fl -^-' '-1 ' ' *' "•>•; t^1-1 !* i ""T" i^r^/C /V'/S^"''<> '-i ^îri'ini'/'x^V' ^HT^S* !A7l*rP "Jll^n CJ?*-MV%'*ai^* -frliia^r'«««•<*• IoKeklârfJ"i;i-.-Qll- o-nH'ÔQ Ul.Q ' -1

Tfei^fit^f&e_grai^wit|r^lMie'| However, the well as far ashouse 9 (on Bent Pine, but rather closer to Deer Run than to Chromatex) has been found tocontain CEs. Based on groundwater sampling, the plume doe^nâ^pe^ê^nd^Jai^shouse 90, which is well northi of the_ she? on Providence^^^^j^êê-o^P^ 'Ri^^^.Investigatiqn.ÔîfcWhjchisûnlgrâ^^^jgroundwater |lumej)O_T!S: S.J r » *Z J —« •" •


It shpuldjfee note4^t£Y??itiie>three houses considered >to be almost definitely iinaffected.bpffieplume i (70, 9Q, andj42SR^3Xlia3 |ome indoor air contaminaints (including 'fiibn§('tfenzâ:e aSUilllTCA)i:|i^nateid^M^HI^

jibe- two Ji^tn^groi me[(f||$eM|j|TCfi has been detected in the air of the following homes: 1, 15, 23,28, 40, and 51. Houses 1,15, and 40 are among the closest to the plant. Houses 23, 28, and .51are more distant; they are on Bent Pine, Deer Run, and Fawn, respectively. 1 1 1TCA has beendetected in the air of many homes: 2, 4, 9, 10, 15*21, 22,^4,^8?44(,37,i3j8,^liaadJD[. Houses2 and 15 are among the closest to Chromatex. The other tefecBons are fame^lcaieffel, and

^ -)t ••"*• - ••" ^W ' i&WR x , ..,.--*. ' t ,~ ' " / ••<"%'• V{-, '•*$$"$ %-?-•$, W^^^r^^T^^ iffP^

house 70 isjon ¥Dessen Drive, outside the immediate neighborhood. OjJyj:iojge^h|!X§&SM§fflE^feiltliijJTfe^^^^ldyiiiJflSsiMiS': 1 5, 28, and 51. 1 5 is one of the closest houses' to thesite; 28 is one of the more distant homes. 51 is somewhat distant from the plant, on Fawn, but itis also close to a potential tetrachloroethene (PCE) plume from an alleged dry-cleaning dump onthe eastern side of the neighborhood. Air from house 51 'has also contained PCE and 1,1-dichloroethane (1 IDC A).

: PCE at 1, 4, 10, 22, 23, and 41; 1,1-dichloroethene(1 1DCE) at 9; cis-l,2-dichoroethene (c!2DCE) at 10; 1,1,2-2-tetrachloroethane at 2; and vinylchloride at 90. Again, house 90 does not appear to be affected by the groundwater plume.

.v . • • • * " - * • « ' . • * * « , £ • • ' • • > < i - f H i ^ i A j • ^ • - < * « " t z > i .••-'-•.,•- -either tadooc or outdoor:;- Thererore,411TCA detections; coiild be 'site-; ^. _ jaT* •*, ,? ' ';'-< .' ~f&' -5J~-*A~!-^ •&. «.a~( JRM.>^>.:~«~i~«'*2w''--- -,•*,•*• •«.,>»_. i.,,.,'-j,. ASv, .ws-^*, ™^«« jl^.-.-AKvm.l^W.-,'.K-,^ n.«**«s«^*i,*m,v& ~»>. . J.nf ,f. f

PADEiPWaimont'f , - - - ! . . - - - , > . , - , ' "<•* ' - ' " - v | v j t

|)Qtentiall^,site^r^rated(base4'on site history (e;g., reported use at<Chromatqx):ana |Befestatus;;as

ammoma,'llllTCA,&butali6lVniethyrene cfflonde;frebri,TF; carbon tetracM6ndeil2iSBEi> ' . . • . - . - " ' • • • _ . , : . - - - t 's- t-. '••'•" T * ; • - • " ,r - •«'•..<•/,- .. «• A -,<fe A'--};--.-,,..-.,, j,.,,.',, •>/,- '• -, ,j. ftiffSfa-^.^/^s^-î'^.'-Ê-y^•1 IDG A; 11DCE, yiriyjl-chlp|ide, ethene, chldroethane,«aceticyaeid, jethane, ethôJ5|cHlorpformjchloromemane, metriane^ && mscellaneou^ Tibnspecifip.chemhave not yet been analyzed for in groundwater. However, it should be noiedjffiatmb|f|of Mesechemicals can also Befoundvin various household sources, especially alcofio|, ammonia, andfreons. Of these chemicals, 111TCA and TCE have been most stronglygromdwater plumie.;"


At a minimum, the following chemicals have been;detected, atTeasfcojace in;mQmtprin!gfof _residential wells near the Chrorriatex plant: chlprirMed ethjbes^^^trans-1,2-dichldroethe;ne ft 12DGE), yinyl'tMd'ndî; '|htoriiiat etlia4is5(ll?i 4| |s-i:S7tribhlproethane, 11DCA, 1,2-dichlorpethanei (,l|2p.CA), chlprpefliane!)^-l%-l*J2-tridhl i |; ftrifluoroetiianei ichloroform; carbon tefraeM\5riie|?foluene; efl|y|b|t&enel xylenes|.,.,. i '^._nv: I_I-_^T—rx Y^^gn4:|)|cppr^Se^rie^spEro^

:While'-some,ieffoFt was usually made to fefnoVe^ p'. .','•, "r -~. V -," '• .-,','.v;r- **. 'i-f 3L-~~-'i?--*-r «..«"' .• -*^- ','i»'»«V"Vf^-"'-«-S : it>1indoor au* sampling \particnlarly: dunngitne" seeondlroiind), Jt/ g»~ • '- ?' v t -^ ;< '^ - -->o|.'»s. .' ^ r^- .-"^ ' -t ."-',-•; -u^"v • ?^ ' - ;&,*?7'; ' -' ' r 'J^'^< ?•

ta^

> . - - .iwaslriotpneces^^\^?-' ^^'•^'J - ^ v ' " .

The tables below show ambient air concentrations obtained by PADEP, the range of positivedetections for ambient air taken by PADEP outside certain residences, the range of indoor airpositive detections in samples taken by EPA and PADEP, and the range of positive detections insoil gas taken by PADEP at the residences. Table 1 A shows these for chlorinated ethenes andethanes; Table IB shows these for other chemicals that were risk drivers or certain commonlydetected chemicals; and Table 1C shows the rest of the chemicals.

The Cindy Drive sample was taken outside the industrial park and is the most likely candidate fora "background" sample. The MW2 sample was taken near the MW-2 Chromatex well; MWASwas taken near the Allsteel plant. The latter two samples then represent ambient airconcentrations within the industrial park.

TABLE 1A

Chemical

11DCE

111TCA

PCE

TCE

U,2,2-tetrachloroethane

c!2DCE

CindyDr.cone.(ug/m3)

MW2amb.cone.(ug/m3)

MWASamb.cone.(ug/m3)

Range ofres.ambients(pos. det.)(ug/m3)

0.085

0.63

Range ofindoor air(pos. det.)(ug/m3)

7.6

0.25 - 1500

1.65-12.21

0.24 - 8.74

1.8

18.64

Range ofsoil gas(pos.det.)(ug/m3)

1.1

REVIEW DRAFT* *DO NOT QUOTE OR CITE**page 4

Chemical

•

11DCA

vinyl chloride


MW2amb.cone.(ug/m3)




0.22

2.56


•

likely*than an mdergroimd or i|

In general, CEs weremot risk drivers; iln|tfii^few case!risk,-'there was:not great consistency ftetJIestthguseXor bjtxfeen roundsintffie^me^^^.«^lthese houses did not forrn a-pattenii Hut \¥erg: scattered; thf^the CE patternjs generally sporadic 'bô&m|pê^d time;

TABLE IB

Chemical

benzene

toluene

ethylbenzene

m,p-xylene

o-xylerie

135TMB*

124TMB*

14DCB**

chloroform


MW2amb.cone.(ug/m3)

1.8

30

2

8

3.2

4.6

17


1.7


0.43 - 0.99

6.8

1.3-1.4

2.9

4.7


0.41 - 32.47

2.88 - 226.65

1.55-35.32

1.2-225.18

2.08-61.81

1.3-49.97

1.50-69.96

0.29-1500

1.1-5.86

Range ofsoil gas(pos.det.) .(ug/m3)

1.2-16

5.8-14

1-1.8

0.96 - 4.7

1.3-2.1

1.6-3.7

1.3


Chemical

carbontetrachloride

1,3-butadiene

CindyDr. 'cone.(ug/m3)

t

MW2amb.cone.(ug/m3)




0.32-10.06

3.4


'

3.2 - 15*TMB = trimethylbenzene ,,,**DCB = dichlorobenzene

™-:r "-> .' i7^*"iji-y" -;.Â --_r<-3-i-' _ * --•; . -y*r^~ -• »• v> -«•" - v, "' A > f »Pi Jfit-tf, "ft? ~*f ~3£/ ^-f" /"' • , .** fs - vj' " f8; r ? .-" i

:i 6si r£TOormSk'dr| er|

JealpifiRluii|e|l&itakcsi ^

Gp^titâHo^n,J^mfih^taj^,is probapl:| loâliKi^"ô^^reag(^êcûseJ^^^^^^^^^fuch,i|biquit£^••_..&._ji.^'-Ji^ .i s .- Si te^* w:~ *hes| pmj sj «";§fe| fe§|o^:'uiird^^^§^M

Chlprdform is often)a; disinfeetioii b^p^du^tan cWoiinMedidnriiang wateri and;tiffislG;Q0dêârimdôrj sourcfe ofJcontamnM6n i e|ateîn thelpublic water supply." However, cnlorof6rm~was also; reported in at least ;orie soiLgas" " i(£ -""•>• - *'-" " i ^ - f *?**••- ••-•"•; ~~s''-- ~ -I??;? '^v'"'- ^KJ " , , * * * *'•"-? ' °'v" • "--V1 " *1^'"' "- -^ ^-'i- 'li"v---v < ^ * •• ' ^( */ **,7i^"' V&"''**•;, \\"*',;•?*'{•,'-•?

sample and has been de|ecjtsuspected toi)e unrelated to the Chrornatex plume,J&erf is;/ " "" :'" - • - -^- -^-^^ ^-sthis conclusion thari for benzene r~ J '1[4lv'<rTi-


PADEP proposed that the listofYOCs related to'the site.groundwater conIr r- " •, v "-'*'" .s " ,<f . •','.- -S * ^,'-- L ;." ->•„: .•- « •-• " fy*,' &*k:'~ ' -'--«<**•'"' **"***«**••

include, carbon; tefrachlbnde^ .TThds:chem£dl: w^Sfoun^: M S.homesJ 2, .28, 36, J7 vf° .5,|)-Three of these homes are^gnFawn and one on Deer Run. darfeoii t e ^ -

"" " ~

TABLE 1C

Chemical

dichlorodifluoromethane (freon12)

chloromethane

trichloi-ofluoromethane (freon 11)

1,2,4-trichlorobenzene

hexachJorobutadiene

acetone

2-butanone

tetrahydrofuran

ethanol

methylenechloride

2-propanol

4-metliyl-2-pentanone

4-ethyltoluene

CindyDr.cone.(ug/iriS)

2.6

1.1

1.3

2.4

2.9

14

3.1

7.1

4.5

MW2amb.cone(ug/m3)

3

1.4

1.7

230

62

22

0.84

7.5

18

11


2.9

1.2

1.2

14

25


2.5-3

0.94-1.4

1.5-1.6

8.2 - 22

6.2-10

8.7 - 48

2.7-3.6


1.76-120

0.63 - 8.88

1.60-137.07

2-6.0

2.2

12.06-200.14

3-32

4.4 - 23

94 - 4600

0.85-107.77

12-61

5 - 59.97

Range ofsoil gas(pos.det).(ug/m3)

2.4-3.1

0.46 - 1

1.2-1.4

9.6 - 140

3.5-19

4.6 - 280

0.68-5.8

3-34

69


Chemical

styrene

13DCB

chlorotoluene

12DCB

hexane

MTBE*

heptane

1,1,2-trichloro-1,2,2-trifluoroethane

1,2-dichloro- .1,1,2,2-tetrafluoroethane

cyclohexane

1,4-dioxane

2-hexanone

carbon disulfide

propylene

bromomethane

wCindyDr.'cone.(ug/m3)

MW2amb.cone(ug/m3)


Range ofres. .ambients(pos. det.)(ug/m3)

• • s

Range ofindoor air(pos. 'det.)(ug/m3)

1.13-4.33

1.6

1.8

2.2

5-13

1.7-5.8

6.6 - 9.3

4.6 - 39.09

15.38-38

7.8

21-25

12 "

2.21 .

Range ofSoil gas(pos.det.)(ug/m3)

0.84-3.1

•,

4.4 - 8.4

8.6

84

7-23

9.5

0.89*MTBE = methyl t-butyl ether

Many of these chemicals are detected in ambient air and soil gas. Several chemicals are presentin soil gas but not ambient air (styrene, hexane, heptane, 1,4-dioxane, carbon disulfide,propylene, and bromomethane). A number of chemicals are present only in indoor air (13DCB,chlorotoluene, 12DCB, MTBE, l,2-dichloro-l,l,2,2-tetrafluoroethane, cyclohexane, 2-hexanone). The chemicals on this table were usually not associated with unacceptable risks.

\

Individual House Results: Nature of Contaminants. Risk, and Consistency over Time


In this section, each house is discussed individually, because each represents an exposure poithat may have been sampled over time. Houses were numbered from 1 to 64 in the immediatevicinity of the Chromatex plant (Deer Run Road, Twin Oaks Road, Bent Pine Road, and FawnDrive). Three houses outside this immediate area were also sampled, and labeled 70,90, and42SR93. The numbering system provides a convenient shorthand for identifying each residencethrough multiple rounds of sampling. Each residence is discussed below. • .

Occasionally, duplicates:br:iround: In that case, both ppsitiy£_dej§^

„-,_*, - - «„ —i v • *vs—*>vf-"f - V-/T , •**" —'^r*?/.*^*- ~-r"^",'ii?":^",t'7' ' ;~":?r'''r f3r - *It should be noted that the conclusioAi presented'heretQithree rounds of ^ê^s^la^êas^fft^f Furthermore, np%(analyzed for in every round. MosywJ&bly,;BenzeneImte^fortheiKStround:

RESIDENCE 1

This residence was sampled twice. PCE was detected once, at a low concentration not associatedwith unacceptable risk. In the 3rd round, TCE was detected in the basement at a concentrationthat could yield unacceptable risk for prolonged, long-term exposure [GIVE SPECIFICNUMBERS FROM 3™ RND ANALYSIS]. However, TCE was not detected on the first floornor in the earlier round, and its risk may therefore be overestimated.

Potentially unacceptable risk was driven mainly by chloroform, benzene, and TMBs. Chloroformdid not pose an unacceptable risk in the first round. Therefore, risks to chloroform may beoverestimated. [INCLUDE SPECIFIC HOURS FOR 3™ ROUND]

The finding of TCE, particularly in the basement and not the first floor, and the one-time findingof PCE, coupled with the proximity of this house to the Chromatex plant, raises the possibilitythat some vapor intrusion may be occurring. It is not apparent that these chemicals are associatedwith a significant and prolonged increase in risk.

At this time, the other chemicals are considered less likely to be related to the groundwater plumeand are suspected to result from ubiquitous sources, although this preliminary conclusion is opento reinteirpretation as the RI progresses.

The complete set of indoor air data is shown below.

Chemical

dichlorodifluoromethane (freon 12)

chloromethane

1st round(ug/m3)

3.96

2.27

3rd roundbasement (ug/m3)

2.97

3rd round 1st floor(ug/m3)

1.49


Chemical

trichlorofluoromethane (freori 11)

methylene chloride

2-butanone

PCE

chloroformi*..

benzene

toluene

ethylbenzene

xylene

o-xylene

135TMB

124TMB

TCE

1st round(ug/m3)

17.42

48,67

8.26

4.75


14.85

2.79

1.34

18.51 "

226.65

19.43

70.64

24.28

6.50

25.49

8.74

3rd round 1st floor(ug/m3) '

23.42

1.94

7.79

88.35

6.62

25.61

8.83

2.75

10.49

RESIDENCE 2n

This residence was sampled three times. Additionally, PADEP collected one soil gas samplefrom the yard. Chlorinated ethanes (111TCA and 1,1,2,2-tetrachloroethane) were detected once,at concentrations not associated with unacceptable risk. TCE was never detected. 111TCA hasbeen detected in the groundwater plume, but has also been detected in many houses, includingthose not believed to be in the plume area and houses where TCE was not detected. It is not clearwhether vapor intrusion is occurring here, although CEs do not appear to contribute significantlyto risk.

Potentially unacceptable risk was driven by 14DCB, benzene, and TMBs (in two consecutiverounds) and chloroform in only one round. Risks to chloroform in particular may beoverestimated. [INCLUDE SPECIFICS FOR 3"° ROUND] At this time, these chemicals appearto be unrelated to the groundwater plume and are suspected to result from ubiquitous sources,although this preliminary conclusion is open to reinterpretation as the RI progresses.


Chemical

dichlorodifluoromethane(freon!2)

trichlorofluoromethane(freonll)

methylene chloride

2-butanone

14DCB

chloromethane

111TCA

chlorofo:rm

carbon tetrachloride

benzene

toluene

ethylbenzene

m,p-xylene

o-xylene

styrene

1 , 1 ,2,2-tetrachloroethane

135TMB

124TMB

13DCB

chlorotoluene

12DCB

1 ,2,4-trichlorobenzene

hexachlorobutadiene

Soil gas(ug/m3)

2.8

1.4

0.68

17

1

16

14

1.4

4.7

2-1

0.84

1.6

-

1st round(ug/m3)

9.40

3.37

107.77

10.32

39.68

2nd round(ug/m3)

4; 3.1

3.4

20

5.9

38; 32

2.4

0.28

1.7; 1.4

0.39

6.0; 5.2

56; 52

7.7; 5.7

37; 24

12; 8.5

2.1

1.8

4.1

16

1.6

1.8

2.2

6.0

2.2

3rd roundbasement(ug/m3)

0.85

1.23

6.15

3rd round1st floor(ug/m3)

1.76» i

2.57

7.77

5.56

1.51

4.22

20.36

3.22

10.60

3^93

5.50


Chemical

acetone

2-propanol

hexane

4-ethyltoluene

ethanol

MTBE

heptane

1,3-butadiene

carbon disulfide

Soil gas .(ug/m3)

66

3.8

8.4

f3

8.6

8.7

23

1st round(ug/m3)

2nd round(ug/m3) .

40

18

6.5

11

1900 ,,

5.8; 5.4

6.6


3"1 round1st floor(ug/m3)

(

RESIDENCE 3

This house was sampled once, in the 1st round. CEs were not detected, and potentiallyunacceptable risks were not identified. At this time, there is no indication that vapor intrusionaffects the indoor air of this home.

Chemical


chloromethane

methylene chloride

2-butanone

14DCB

Ground (ug/m3)

32.14

8.88

6.60

6.78

7.21

RESIDENCE 4

This home was sampled once, during the 3rd round. Basement and lst-floor samples werecollected. PCE and 111TCA were detected in the lst-floor air, and 111TCA was also detected inthe basement, although the concentrations of these CEs would not be associated withunacceptable risk. It is not clear whether vapor intrusion is occurring here, although CEs do notappear to contribute significantly to risk.

REVIEW. DRAFT**DO NOT QUOTE OR CITE**page 12

Risk on both floors was driven by benzene and TMBs, which had fairly consistent concentrationsfrom floor to floor. [GIVE SPECIFICS FOR 3™ RND] At this time, these chemicals appear tobe unrelated to the groundwater plume and are suspected to result from ubiquitous sources,although this preliminary conclusion is open to reinterpretation as the RI progresses.

Chemical ' •

trichlorofluoromethane (freon 11)

111TCA

benzene

toluene

PCE

xylene

124TMB

acetone

2-butanone

4-ethyltoluene


ethylbenzene

3rd round basement (ug/m3)

11. 42; 11. 42

16.64; 16.64

9.74; 6.49

23.05; 23.05

5.00; 5.00

24.11; 50.64

6.00; 11. 99

5.00; 5.00

ND; 5.03

ND; 8.83

3rd round 1st floor '(ug/m3)

11.42

16.64

6.49

26.89

6.89

8.83

5.00

31.35

8.99

5.00

RESIDENCE 5 was not sampled.

RESIDENCE 6

This house was sampled once, in the 1st round. 111TCA was detected at a concentration notassociated with unacceptable risk. TCE was not detected. 111TCA has been detected in thegroundwater plume, but has also been detected in many houses, including those not believed tobe in the plume area and houses where TCE was not detected. It is not clear whether vaporintrusion is occurring here, although CEs do not appear to contribute significantly to risk.

Chemical


methylene chloride

111TCA

1st round (ug/m3)

2.47

6.60

4.36




RESIDENCE 9if.

This residence was sampled three times. During the 2nd round, two ambient air samples amd onesoil gas sample were also taken in the yard. In each round, the chemicals associated withpotentially unacceptable risk were different (1st round: 14DCB; 2nd round: 11DCE and111TCA; 3rd round: chloroform, benzene, trimethylbenzenes). [INCLUDE MORE SPECIFICSON 3*° RNDXRISKS] Therefore, it appears that the risks were overestimated, because there isno evidence that the chemicals are available for prolonged, long-term exposure. 14DCB aondTMBs were not detected in ambient air or soil gas. Benzene was detected in both ambient airsamples and in soil gas. Other than the risk drivers in the 2nd round, these chemicals appear tobe unrelated to the groundwater plume and are suspected to result from ubiquitous sources,although this preliminary conclusion is open to reinterpretation as the RI progresses.

11DCE is a possible breakdown product of TCE, and was also detected in the ambient air,indicating a possible outdoor source. 111TCA was a risk driver in the 2nd round, and wasdetected in both the first-floor and basement samples from the third round, although at lower(acceptable) levels. 111TCA has been detected in the groundwater plume, but has also beendetected in soil gas, ambient air, and the indoor air of many houses, including those not believedto be in the plume area and houses where TCE was not detected. (TCE was never detected inthis house.) The groundwater plume is known to exist in the formerly used domestic well atResidence 9. It is not clear whether vapor intrusion is occurring here, although sustained adverseimpacts on air quality from vapor intrusion have not been observed to date.

Chemical


l,l,2-trichloro-l,2,2-trifluoroethane

2-butanone

111TCA

14DCB

Ambientair range(pos. det.)(ug/m3)

1.5

6.2

0.63

Soil gas(ug/m3)

1.2

4.6

1.1

Ground(ug/m3)

5.06

39.09

8.85

5.46

204.42

2nd

round(ug/m3)

15

1500;1200

3.7

3"| roundbasement(ug/m3)

2.40',

4.22

i

3rd

round1st floor(ug/m3)

2.80

2.94

9.78


Chemical

cfichlorodifluoromethane(freon 12)

methylene chloride

1,1-dichloroethene

m,p-xylene

acetone

2-propanol

ethanol

chloroform

benzene

toluene

124TMB

chloromethane


propylene

Ambient ,' air range(pos. det.)(ug7m3)

2.5-2.8

0.085

1.4"

22 ,

3.6

48

0.43 -0.68

0.97

Soil gas(ug/m3)

3.1

1.3

26

3.2

8.2

1.3

1.2

9.5

1st round(ug/m3)

ond

round(ug/m3)

2.5

4.8

7.6

4.6

36

43

160


31.80

2.47

0.91

8.84

2.50

1.18

5.68

t

ttft3rd

round1st floor(ug/m3)

19.08

1.64

0.94

11.91

3.00

RESIDENCE 10

This house was sampled twice. In the 1st round, c!2DCE and chloromethane had the highestrisk, although the risk occurred just at EPA's acceptable levels. In theSrd round, potentiallyunacceptable risks were driven by benzene and TMBs (in both the 1st floor and basement).[GIVE MORE SPECIFICS OF 3™ RND RISKS]

111TCA was detected once, in the 3rd round (1st floor but not basement). TCE was neverdetected. The inconsistency of the results means that long-term risks may be overestimated forthis home.

While c!2DCE can be a breakdown product of TCE, and 111TCA was reported in thegroundwater plume, the inconsistency of the results makes it difficult to determine whether vapor


intrusion is occurring. Additionally, 111TCA has also been detected in many houses, includingthosfe not believed to be in 'the plume area and houses where TCE was not detected. However,CEs do not appear to contribute significantly to risk.

At this time, the benzene and TMBs appear to be unrelated to the groundwater plume and aresuspected to result from ubiquitous sources, although this preliminary conclusion is open toreinterpretation as the RI progresses.

Chemical

chloromethane

methylene chloride

2-butanone

111TCA

cis-12DCE


benzene

toluene

ethylbenzene

xylene

styrene

o-xylene

124TMB


trichlorofluoromethane (freon 1 1)

PCE

1st round(ug/m3)

4.13; 3.51

66.05; 66.05

14.45; ND

17.46; 19.64

ND; 18.64

3"1 roundbasement (ug/m3)

1.34;2.'04

2.76; 2.26

2.66; 2.71

3.90; 4.55

13.06; 17.67

1.68; 1.99

6.62; 8.39

2.08; 2.65

1.95; 2.45

ND; 1.71

ND; 1.93

3rf round 1st

floor (ug/m3)

8.19 '

2.08

1.72

2.46

10.07

33.42

4.86

18.99

1.78

5.74

6.50

2.69



RESIDENCE 13


This house was sampled once, in the 1st round. CEs were not detected, and potentiallyunacceptable risks were not identified. At this time, vapor intrusion into the indoor air of thishome does not appear probable.

Chemicali


methylene chloride

2-butanone

1st round (ug/rri3)

2.81

48.67

19.46

RESIDENCE 14 ' ' .

This house was sampled twice. CEs were never detected, and potentially unacceptable risks werenever identified. At this time, vapor intrusion into the indoor air of this home does not appearprobable.

Chemical

1,1,2-trichloro- 1,2,2-trifluoroethane

dichlorodifluoromethane(freon 12)

trichlorofluoromethane(freon 11)

methylene chloride

benzene

toluene

xylene

1st round (ug/m3)

8.43

3rd round basement(ug/m3)

1.77

1.63

1.72

5.76

2.65


2.46

2.06

4.93

0.94

4.23

RESIDENCE 15

This residence was sampled twice. TCE was detected once, and 111TCA was detected once (in adifferent round, and in both basement and Ist-floor samples). Neither of these chemicalscontributed to an unacceptable risk.

This house is one of the closest houses to the Chromatex plant. However, the inconsistency ofthe results makes it difficult to determine whether vapor intrusion is occurring. Additionally,


111TCA has also been detected in many houses, including those not believed to be in the plume 'area and houses where TCE was not detected. However, CEs do not appear to contributesignificantly to risk.

Potentially unacceptable risk hi the 3rd round was driven by benzene, toluene, andtrirnethylbenzenes. [GIVE MORE DETAILS] At this time, these chemicals are considered lesslikely to be related to the groundwater plume and are suspected to result from ubiquitous sources,although this preliminary conclusion is open to reinterpretation as the RI progresses.

Chemicali»



1 , 1 ,2-trichloro- 1 ,2,2-trifluoroethane

methylene chloride

2-butanone

TCE

chloromethane

111TCA

benzene

toluene

ethylbenzene

xylene

o-xylene

135TMB

124TMB

1st round (ug/m3)

5.44

73.04

4.60

21.90

28.90

4.84


6.03

27.41

6.71

1.11

12.20

15.91

192.08

33.11

132.46

48.57

13.99

54.97

3ri round 1st

floor (ug/m3)

4.73

19.42

6.71

1.28

4.05

14.94

188.23

28.26

114.80

41.94

10.49

46.47

RESIDENCE 16

This residence was sampled twice. CEs were never detected. At this time, vapor intrusion intothe indoor air of this home does not appear probable. Potentially unacceptable risk in the thirdround was driven by freons (dichlorodifluoromethane and trichlorofluoromethane) and benzene,on the first floor only. [GIVE MORE DETAILS] At this time, these chemicals appear to be


<

probably unrelated to the groundwater plume and 'are suspected to result from ubiquitous sources,although this preliminary conclusion is open to reinterpretation as the RI progresses.

Chemical

dichlorodifluoromethane (freoh 12)


methylene chloride

benzene

toluene

xylene

chloromethane

1st round(ug/m3)

6.43

12.36

20.16


3.52

5.65

i:io

0.67

3ril round 1st floor(ug/m3) .

30.16

137.07

1.14

6.53

3.31





RESIDENCE 21

This house was sampled twice. 111TCA was detected once (in both the l^-floor and basementair), at concentrations not associated with unacceptable risk. TCE was never detected. 111TCAhas been detected in the groundwater plume, but has also been detected in many houses,including; those not believed to be in the plume area and houses where TCE was not detected. Itis not clear whether vapor intrusion is occurring here, although CEs do not appear to contributesignificantly to risk.

Potentially unacceptable risk in the third round was driven by chloroform. [ GIVE MOREDETAILS] Chloroform did not pose an unacceptable risk in the first round. Therefore, risks tochloroform may be overestimated. Chloroform may be unrelated to the groundwater plume and,at this time, is suspected to result from ubiquitous sources, although this preliminary conclusionis open to reinterpretation as the RI progresses.


Chemical

chloromethane

methylene chloride

2-butanone

111TCA



chloroform

benzene

toluene

1st round(ug/m3)

2.68

17.73

6.49

28.37


1.68

2,08

36.60

2.56•

1.49

2.88

3rd round 1st

floor (ug/m3)

1.41

0.85

7.21

2.36

1.94 '

2.78

1.07

11.91

RESIDENCE 22

This house was sampled three times. CEs were detected in all three rounds, although never atconcentrations associated with unacceptable risk (first round: PCE; second round: PCE and111TCA; third round: 111TCA on both floors and PCE on the first floor).

The consistency of these results raises the possibility that some vapor intrusion may be occurring.However, indoor sources are also a possibility. 111TCA has been detected in the groundwater.plume, but has also been detected in many houses, including those not believed to be in theplume area and houses where TCE was not detected. This residence is not one of the closerresidences to the site, although it is at least as close as another residence where the plume isknown to exist. In any case, CEs do not appear to contribute significantly to risk.

Potentially unacceptable risk was driven by freons (dichlorodifluoromethane, and oncetrichlorofluoromethane), benzene, TMBs, and 14DCB in more than one round. First-floor andbasement samples were fairly consistent. [GIVE MORE DETAILS ABOUT 3™ RND] At thistime, these chemicals appear to be probably unrelated to the groundwater plume and aresuspected to result from ubiquitous sources, although this preliminary conclusion is open toreinterpretation as the RI progresses.

Two ambient air and two soil gas samples were also taken from the yard by PADEP. CEs werenot detected in either type of sample, suggesting that indoor sources of these chemicals may bemore likely than outdoor or underground sources. Freons were detected in both media. Benzeneand 14DCB were detected in ambient air, indicating the possibility of outdoor sources.


Chemical

dichloroclifluoromethane (fireon 12)

1,2-dichloro-1,1,2,2-tetraflu'oroethane


1,1,2-trichloro-1,2,2-trifluoroethane

111TCA

PCE

14DCB

benzene

toluene

ethylbenzene

m,p-xylene

o-xylene

124TMB

acetone

2-propanol

2-butanone

tetrahydrofuran

Rangeofambientair (pos.det.)(ug/m3) ,

2.7 - 2.7

4.7

0.46

8.5

2.7


2.6-2.7

1.4

0.96

9.6-16

3.5

1st round(ug/m3)

74.18

15.38

35.40

12.26

35.46

12.21

72.15

2nd round(ug/m3)

120; 120; 100;100

37; 38

37; 37

18; 18; 17; 18

3.5; 3.6

1200; 1300;1400; 1500

8.0; 8.6; 7.7;7.8

44; 48; 49; 50

6.5; 7.1; 7.3;7.5

24; 24; 27; 28

8.4; 9.3; 10; 10

9.6; 10

62; 52

14; 16

32; 31

16; 16


40.72

17.05

18.28

3.66

733.38

2.37

12.6,8

1.55

6.18

2.08

2.55

.

3rd

round 1st

floor(ug/m3)

48.76

20.61

22.27

4.44

2.83

1038.96

2.73 •

14.21

1.72

7.06

2.43

3.30


Chemical1

'

ethanol

chloromethane

methylenechloride

Rangeofambientair(pos.det.)(ug/m3)

10

0.94

V


4.6 - 9.6

0.46

1.1-5.8

1st round(ug/m3)

2nd round(ug/m3).

250; 280

i


1.09

5.30 .

3rd

round 1st

floor(ug/m3)

1.28

11.66

RESIDENCE 23

This house was sampled twice. TCE was detected in one round and PCE in another, but atconcentrations not associated with unacceptable risk. While the detection of CEs would seem tosuggest vapor intrusion, it is not clear whether that is occurring here. The TCE and PCE werenot detected at the same tune, and PCE was detected in the 1st floor but not the basement.Therefore, the results are inconclusive. However, CEs do not appear to contribute significantlyto risk. All other chemicals were also detected at acceptable concentrations.

Chemical

1 , 1 ,2-trichloro- 1 ,2,2,-trifluoroethane

TCE


chloromethane


methylene chloride

benzene

toluene

PCE

xylene

Ground(ug/m3)

9.20

5.91


t

2.61

1.24

1.77

10.25

1.14

9.60

3rd round 1st

floor (ug/m3)

3.22

1.39

5.43

3.89

1.27

9.60

1.65

2.47

RESIDENCE 24


Residence 24 was only sampled once. 111TCA was detected in the basement, although not atconcentrations associated with unacceptable risk. This result raises the possibility that somevap6r intrusion may be occurring. However, indoor sources are also a possibility. This residenceis not one of the closer residences to the site, although it is perhaps as close as another residencewhere the plume is known to exist. 111TCA has been detected in the groundwater plume, buthas also been detected in many houses, including those not believed to be in the plume area andhouses where TCE Was not detected. In any case, CEs do not appear to contribute significantlyto risk.

Potentially unacceptable risk was driven by benzene and TMB. [GIVE MORE DETAILS] First-floor and basement samples were fairly consistent. At this time, these chemicals appear to beunrelated to the groundwater plume and are suspected to result from ubiquitous sources, althoughthis preliminary conclusion is open to reinterpretation as the RI progresses.

Chemical

chloromethane

methylene chloride

benzene

toluene

ethylbenzene

xylene

o-xylene

124TMB

acetone

2-butanone

4-ethyltoluene

111TCA

3rd round basement (ug/m3)- 1

12.99

46.10

4.42

26.49

8.83

5.00

38.58

5.00

5.55

3rd round 1st floor (ug/m3)

4.20

7.07

9.74

30.73

3.97

17.66

4.42

5.00

33.76

3.00

5.00

RESIDENCE 25

This residence was sampled twice. CEs were never detected. At this time, it does not appearhighly likely that vapor intrusion affects the indoor air of this home. Potentially unacceptablerisk in the 3rd round was driven by benzene and TMBs on both floors. [GIVE MORE DETAILS]At this time, these chemicals appear to be unrelated to the groundwater plume and are suspectedto result from ubiquitous sources, although this preliminary conclusion is open to reinterpretation


as the RI progresses.

Chemical


methylene chloride


chloromethane

benzene

toluene

ethylbenzene

xylene

o-xylene

124TMB


1s1 round(ug/m3)

6.18

12.17


3.94

6.36

3.62

1.18

6.17

32.65

2.74

10.60

3.49

3.70

2.87

3rd round 1st

floor (ug/m3)

3.03

10.60

4.62

1.24

1.43 ''

29.96

1.94

7.06

2.38

2.15

RESIDENCE 26

This house was sampled twice. CEs were never detected, and potentially unacceptable risks werenever identified. At this time, it appears unlikely that vapor intrusion affects the indoor air ofthis home. i.

Chemical

methylene chloride

benzene

toluene

ethylbenzene

xylene

14DCB

acetone

1st round (ug/m3)

8.00


2.92

15.37

8.83

8.83

12.06


15.37

6.11

36.17



RESIDENCE 28

This house was sampled three times. In the 2nd round, TCE was detected in the basement at aconcentration that could yield unacceptable risk for prolonged, long-term exposure. However,TCE was not detected in the previous or subsequent rounds, and its risk is therefore probablyoverestimated. 111TCA was detected once, at concentrations not associated with unacceptablerisk. 111TC A has been detected in the groundwater plume, but has also been detected in manyhouses, including those not believed to be in the plume area and houses where TCE was notdetected. In the 2nd round, PADEP obtained soil gas from the yard. CEs were not detected,suggesting that the source of the CEs may not be underground. It is not clear whether vaporintrusion is occurring here, nor whether these chemicals are associated with a significant andprolonged increase in risk.

Potentially unacceptable risk in the indoor air was driven by chloroform, carbon tetrachloride(once), benzene, and/or TMBs. [GIVE MORE DETAILS ABOUT 3™ RND] None of thesechemicals were detected in soil gas, suggesting that indoor or outdoor sources of thesecontaminants may be more likely than underground sources. At this time, benzene and TMBsappear to be unrelated to the groundwater plume and are suspected to result from ubiquitoussources, although this preliminary conclusion is open to reinterpretation as the RI progresses. Therelationship of chloroform and carbon tetrachloride to the plume is questionable.

Chemical

trichlorofluoromethane (freon

11)

methylene chloride

chloroform



chloromethane

111TCA

benzene

TCE

Soil gas(ug/m3)

2.8

1st round(ug/m3)

3.37

15.99

5.86

10.06

2nd round(ug/m3)

2.3

0.73

1.3; 1.1

0.32

3.3; 2.9

1.5

5.9; 5.7

3.9; 3.2

3.8; 2.8


2.06

1.27

2.21

1.85

3.90


3.71

1.24

2.82

1.91

3.21


Chemkal

toluene

ethylbenzene

m,p-xylene

o-xylene

135TMB

124TMB

14DCB

acetone

2-propanol

2-butanone

hexane

cyclohexane

1 ,4-dioxane

ethanol

heptane

MTBE

Soil gas(ug/m3)

1.2

140

34

15

7.8

1st round(ug/m3)

2nd round(ug/m3).

18; 15

2.4; 1.8

10; 6.7

3.7; 2.4

1.3 . ,

3.8

0.63

34

45

4.4

13

7.8

25

200

9.3 .

3.0

3rd roundbasement(ug/m3) '

16.52

2.03

7.95

2.78

3.15


37.26

1.85

6.62

2.30

t

3.10






RESIDENCE 34

This house was sampled once. 111TCA was detected on the 1st floor, although not at


concentrations associated with unacceptable risk.' This result raises the possibility that somevapor intrusion may be occurring. However, indoor sources are also a possibility, especially since111TCA was not detected in the basement. 111TCA has been detected in the groundwaterplume, but has also been detected in many houses, including those not believed to be in theplume area and houses where TCE was not detected. In any case, CEs do not appear tocontribute significantly to risk.

Potentially unacceptable risk was driven by benzene and TMBs. [GIVE MORE DETAILS]First-floor and basement samples were fairly consistent for benzene; 124TMB was only detectedin the basement. At this time, these chemicals appear to be unrelated to the groundwater plumeand are suspected to result from ubiquitous sources, although this preliminary conclusion is opento reinterpretation as the RI progresses.

Chemical

111TCA

benzene

toluene

ethylbenzene

xylene

o-xylene

acetone

4-ethyltoluene

124TMB

2-butanone


\

12.99

57.62

8.83

26.49

8.83

24.11

9.99

9.99

6.00


5.55

16.23

65.31

8.83

35.32

8.83

36.17

9.99

RESIDENCE 35 was npt sampled.

RESIDENCE 36

This home was sampled twice. CEs were never detected.

Potentially unacceptable risk was driven by benzene and TMBs in both rounds, and on bothfloors in the 3rd round. [GIVE MORE DETAILS ABOUT 3™ RND] Chloroform and carbontetrachloride were associated with potentially unacceptable risk in the 2nd round only; they werenot detected in the 3rd round, indicating that long-term risks from these chemicals may beoverestimated.


-<i/,Benzene was detected in both ambient air and soil gas samples taken outside the home during the2nd round. 124TMB was detected in ambient air but not soil gas, indicating that outdoor sourcesare possible. Chloroform and carbon tetrachloride were not detected in ambient air or soil gas,suggesting that indoor sources' may be more likely. At this time, these chemicals appear to beunrelated to the groundwater plume, or to have a questionable association, although thispreliminary conclusion is open to reinterpretation as the RI progresses.

Chemical


chloromethane


chloroform


benzene

toluene

ethylbenzene

m,p-xylene

o-xylene

14DCB

135TMB

124TMB

acetone

2-propanol

2-butanone

4-ethyltoluene

ethanol

MTBE

Ambient air(ug/m3)

3

1.4

1.6

0.99

6.8

1.3

2.9

14

10

8.7

Soil gas(ug/m3)

2.7

1.4

2.3

1.5

35

3

10

15

2nd round(ug/m3)

2.4; 2.6; '2.4

1.2

6.5

3.6; 3.7; 3.4

0.52; 0.49

2.1; 1.9; 1.8

14; 18; 16

2.5; 2.9; 2.5

12; 12; 9.9

5.5; 5.4; 4.3

0.54; 0.42

2.2

11

45

21

16

7

3500

2.0; 1.7


9.74

57.62

8.83

30.91

8.83) i

9.99

86.81

9.99


• ,

12.99

72.99

8.83

44.15

13.25

14.99

57.87

14.99


Chemical

methylene chloride

1,3-butadiene

carbon disulfide

4-methyl-2-pentanone

Ambient air(ug/m3)

Soil gag(ug/m3)

3.2

7

69

2nd round(ug/m3)


10.60


RESIDENCES?

This house was sampled once, in the 2nd round. 111TCA was detected, although not atconcentrations associated with unacceptable risk. This result raises the possibility that somevapor intrusion may be occurring. Hpwever, indoor sources are also a possibility. 111TCA hasbeen detected in the groundwater plume, but has also been detected in many houses, includingthose not believed to be in the plume area and houses where TCE was not detected. In any case,CEs do not appear to contribute significantly to risk at this home.

Potentially unacceptable risk was driven by benzene, TMBs, chloroform, carbon tetrachloride,1,3-butadiene, and toluene. If these chemicals are not consistently present over the long term,risks from these chemicals may be overestimated.

Benzene was detected in both ambient air and soil gas samples taken outside the home during the2nd round. TMBs, toluene, and 1,3-butadiene were detected in soil gas but not ambient air.Chloroform and carbon tetrachloride were not detected in ambient air or soil gas, suggesting thatindoor sources may be more likely. At this time, these chemicals appear to be unrelated to thegroundwater plume or to have a questionable association, although this preliminary conclusion isopen to reinterpretation as the RI progresses.

Chemical


chloromethane

111TCA



chloroform

Range of ambient air(pos. det.) (ug/m3)

2.6-3

1

Soil gas(ug/m3)

2.4

0,88

1.3

2nd round (ug/m3)

2.8; 3.0

4.5; 2.0

0.25

7.7

0.48

1.8


Chemical

benzene

toluene

ethylbenzene

m,p-xylene

o-xylene

styrene

14DCB

135TMB

124TMB

1,3-butadiene

acetone

2-propanoI

2-butanone

ethanol

MTBE

heptane

4-ethyltoluene

bromomethane

methylene chloride

carbon disulfide

hexane

1 ,4-dioxane

Range of ambient air(pos. det.) (ug/m3)

0.6

8.2

17

Soil gas(ug/m3)

9

11

1.8

4.7

2

1.3

2

15

31

3

16

5.2

0.89

0.81

14

6.6

84

2nd round (ug/m3)

9.7; 10

88; 100

13; 13

51; 57

18; 18

1.8

0.64

4.6

20

3.4

110

61

24

3000

5.0; 4.9

16.8

16

RESIDENCE 38

This house was sampled once. 111TCA was detected on the 1st floor, although not atconcentrations associated with unacceptable risk. This result raises the possibility that some


sincevapor intrusion may be occurring. However, indoor sources are also a possibility, especially si111TCA was not detected in the basement. 111TCA has been detected in the groundwaterplume, but has also been detected in many houses, including those not believed to be in theplume area and houses where TCE was not detected. In any case, CEs do not appear tocontribute significantly to risk.

Potentially unacceptable risk was driven by benzene and TMB. [MORE DETAILS] First-floorand basement samples were fairly consistent. At this time, these chemicals appear to beunrelated to the groundwater plume and are suspected to result from ubiquitous sources, althoughthis preliminary conclusion is open to reinterpretation as the RI progresses.

Chemical

dichloroclifluoromethane(freon 12)

111TCA

benzene

toluene

ethylbenzene

xylene

o-xylene

135TMB

124TMB

acetone

2-butanone

4-ethyltoluene


9.74

.61.46

8.83

35.32

8.83

5.00

40.99

8.99

9.99

3fd round 1 rt floor (ug/m3)

4.52

4.99

9.74

69.15

8.83

35.32

13.25

4.00

9.99

57.87 ' .

6.00

9.99

RESIDENCE 39

This residence was sampled twice. CEs were never detected. At this time, it appears unlikelythat vapor intrusion affects the indoor air of this home. Potentially unacceptable risk in the 3rdround was driven by chloroform, with some possible contribution from benzene andtrimethylbenzenes. [MORE DETAILS] Chloroform was not detected in the 1st round.Therefore, risks to chloroform may be overestimated. At this time, these chemicals appear to beunrelated to the groundwater plume or to have a questionable association, although thispreliminary conclusion is open to reinterpretation as the RI progresses.


Chemical

methylene chloride

dichlorodifluoromethane(freon!2)

chloromethane


chloroform

benzene

toluene

ethylbenzene

124TMB

xylene

1st round(ug/m3)

3.48

t\


6.36

2.41

1.36

1.88

2.43

1.36

25.35 '

1.60

3.40

3rd round 1st floor(ug/m3) '

5.30

2.26

1.28

1.77

2.63

1.27

11.52

2.91

1.50

RESIDENCE 40

This house was sampled twice. TCE was detected once, at concentrations not associated withunacceptable risk. It is not clear whether vapor intrusion is occurring here, although CEs werenot detected consistently and do not appear to contribute significantly to risk.

Potentially unacceptable risk in the 3rd round was driven by benzene and TMBs, on both floors.[MORE DETAILS] At this time, these chemicals appear to be unrelated to the groundwaterplume and are suspected to result from ubiquitous sources, although this preliminary conclusionis open to reinterpretation as the RI progresses.

Chemical

methylene chloride

TCE



benzene

1* round(ug/m3)

7.65

2.69


2.19

2.51

1.77

3.12

3rd round 1st

floor (ug/m3)

1.70

2.31

2.97

4.22


Chemical

toluene

ethylbenzene

xylene

styrene

o-xylene

124TMB

chloromethane

1st round(ug/m3)


19.59

2.69

11.92

3:75

4.05 ,

1.47

3rd round 1st

floor (ug/m3)

28.04

3.75 .

15.89

1.52

4.86

5.50

RESIDENCE 41

This house was sampled twice. PCE was detected once, at concentrations not associated withunacceptable risk. It is not clear whether vapor intrusion is occurring here, although CEs werenot detected consistently and do not appear to contribute significantly to risk.

Potentially unacceptable risk in the 3rd round was driven by chloroform (1st floor only) andtoluene, benzene and TMBs on both floors. [MORE DETAILS] At this time, these chemicalsappear to be unrelated to the groundwater plume or to have a questionable association. They aresuspected to result from ubiquitous sources, although this preliminary conclusion is open toreinterpretation as the RI progresses.

Chemical

methylene chloride

PCE



chloroform

benzene

toluene

ethylbenzene

1st round (ug/m3)

4.87

6.10

3rd roundbasement (ug/m3) '.

4.24

2.46

1.83

15.26

145.98

21.19

3rd round 1st

floor (ug/m3)

1.31

2.46

3.43

3.82

23.70

215.12

32.67


Chemical

xylene

styrene

o-xylene

135TMB

124TMB

chloromethane

1st round (ug/m3) 3rd roundbasement (ug/m3)

88.30

29.58

8.00

33.48

1.28

3rd round 1st

floor (vag/m3)

136.87

1.13 .

44.15

10.49

43.98»


RESIDENCE 43

This home was sampled once, in the 1st round. CEs were not detected, and potentiallyunacceptable risks were not identified. At this time, it does not appear likely that vapor intrusionaffects the indoor air of this home.

Chemical


methylene chloride

1st round (ug/m3)

4.49

11.12

RESIDENCE 44 was not sampled. i




RESIDENCE 48

Residence 48 was sampled during the 3rd round. No CEs were detected, and vapor intrusion doesnot appear highly likely. Potentially unacceptable risks were driven by benzene in both the 1st

floor and basement. [MORE DETAILS] At this time, benzene appears to be unrelated to thegroundwater plume and is suspected to result from ubiquitous sources, although this preliminaryconclusion is open to reinterpretation as the RI progresses.


Chemical

chloromethane

benzene

toluene

ethylbenzene

xylene

o-xylene

acetone

2-butanone

4-ethyltoluene

styrene


6.30

9.74

57.62

4.42

22.08

,8.83

96.45

8.99

5.00

4.33


6;30

12.99

72.99

8.83

35.32

8.83

98.87

11.99

5.00



RESIDENCE 51

This house was sampled three times. CEs were detected in all three rounds, although never atconcentrations associated with unacceptable risk (first round: PCE; second round: PCE, TCE,'111TCA and 11DCA; third round: 111TCA on both floors).

iThe consistency of these results raises the possibility that some vapor intrusion may be occurring.Additionally, this home is downhill from the alleged dry-cleaning dump, where soil PCE wasdetected. However, indoor sources are also a possibility, and CEs were not detected in soil gastaken outside this house. 111TCA has been detected in the groundwater plume, but has alsobeen detected in many houses, including those not believed to be in the plume area and houseswhere TCE was not detected. In any case, CEs do not appear to contribute significantly to risk.

Potentially unacceptable risk was driven by chloroform, benzene, and TMBs, and iri'one instanceby 2-hexanone and carbon tetrachloride. [MORE DETAILS ON 3™ RND] First-floor andbasement samples were fairly consistent. Of these chemicals, only benzene was detected in soilgas. At this time, these chemicals appear to be unrelated to the groundwater plume or to have aquestionable association, although this preliminary conclusion is open to reinterpretation as theRI progresses.


Chemical

dichlorodifluoromethane(fireon 12)


methylene chloride

chloroform

PCE

11 DC A

chloromethane

111TCA


benzene

TCE

toluene

ethylbenzene

m,p-xylene

o-xylene

14DCB

styrene

135TMB

124TMB

acetone

2-propanol

2-butanone

Soil gas(ug/m3)

2.6; 2.6

1.4; 1.4

i*

;\• i

2.5; 3.1

1.1; 0.96

92; 91

6.2; 6.4

16; 16

1st round(ug/m3)

3.46; 3.96

3.37; 4.49

16.34;19.82

4.88; 5.86

5.42; 6. 10

,,

2nd round(ug/m3).

2.6; 2.7

3.9

i

3.3; 3.5

1.9; 1.8

0.22

1.3

7.0; 7.5

1.1

4.6; 5.1

0.24

28; 38

2.8; 3.2

11;11

5.2; 5.3

0.29

1.6

1.8

7.2

68

61

16


1.60

1.05

3.99

5.52

21.51

4.19

13.69

5.30

2.00

7.50

•

3rd round1* floor(ug/m3)

•

2.34 •

0.95

4.17

0.63

3.72

5.84

24.20 ,

3.93

13.25

4.86

2.05

8.00


Chemical

hexane

tetrahydrofuran

2-hexanone

4-ethyltoluene

ethanol

MTBE

1,3 -butadiene

carbon disulflde

Soil gas(ug/m3)

7.2; 7.2

8.6; 7.1

4.6; 4.3

9; 8.9 ..;

1st round(ug/m3)

2nd round(ug/m3)

5.0

23

12

6.4

4600

4.5; 4.5


3"1 round1st floor(ug/m3)

•


RESIDENCE 53

This residence was sampled twice. CEs were never detected. At this time, it does not appearhighly likely that vapor intrusion affects the indoor air of this home. Potentially unacceptablerisk in the third round was driven by toluene, benzene and TMBs. [MORE DETAILS] Results inthe 3rd round appear to be fairly consistent between the basement and 1st floor, although all ofthese chemicals are somewhat higher in the 1st floor air. At this time, these chemicals appear tobe unrelated to the groundwater plume or to have a questionable association. They are suspectedto result from ubiquitous sources, although this preliminary conclusion is open to reinterpretationas the RI progresses.

Chemical


methylene chloride

benzene

toluene

ethylbenzene

xylene

1st round(ug/m3)

3.93; 2.81

4.17; 5.56


4.00

29.22

122.93

22.08

79.47

3rd round 1st

floor (ug/m3)

32.47

142.14

22.08

92.72


Chemical

o-xylene

135TMB

124TMB

acetone

4-ethyltoluene

2-butanone

Mst round(ug/m3)

3rd round basement(ug/m3) .

22.08

5.00

14.99

55.46

19.99

6.00 ' • ' '

3rd round 1st

floor (ug/m3)

26.49

9.99

24.99

86.81

24.99' (

RESIDENCE 54

This residence was sampled once, in the 3rd round. CEs were not detected. At this time, it doesnot appear highly likely that vapor intrusion affects the indoor air of this home. Potentiallyunacceptable risk in the third round was driven by toluene, benzene and TMBs. [MOREDETAILS] Results in the 3rd round appear to be fairly consistent between the basement and 1st

floor, although all of these chemicals are somewhat higher in the basement air. At this time,these chemicals appear to be unrelated to the groundwater plume or to have a questionableassociation. They are suspected to result from ubiquitous sources, although this preliminaryconclusion is open to reinterpretation as the RI progresses.

Chemical

benzene

toluene

ethylbenzene

xylene

o-xylene

124TMB

acetone

2-butanone

4-ethyltoluene

chloromethane

135TMB


16.23

126.77

22.08

66.23

22.08

14.99

91.63

26.98

14.99

1.89

4.50


9.74

76.83 ''

8.83

39.74

13.25

14.99

28.94

8.99

14.99


RESIDENCE 55

This residence was sampled once, in the 3rd round. CEs were not detected. At this time, itappears highly unlikely that vapor intrusion affects the indoor air of this home. Potentiallyunacceptable risk in the third round was driven by toluene, benzene and TMBs in the basementonly (risks were acceptable for the 1st floor). [MORE DETAILS] At this time, these chemicalsappear to be unrelated to the groundwater plume or to have a questionable association. They aresuspected to result from ubiquitous sources, although this preliminary conclusion is open toreinterpretation as the RI progresses.

'(>

Chemical

benzene

toluene

ethylbenzene

xylene

o-xylene

135TMB

124TMB

acetone

2-butanone

carbon disulfide

4-ethyltoluene


32.47; 6.49

142.14; 30.73

35,32; 3.97

225.18; 13.25

61.81; 4.42

49.97; ND

69.96; 4.50

79.57; 118.16

3.00; 23.98

2.21 ;ND

59.97; 4.50


7.68

200.14

3.00





RESIDENCE 60

This home was sampled once, in the 1st round. CEs were not detected, and potentiallyunacceptable risks were not identified. At this time, there is no indication that vapor intrusionaffects the indoor air of this home.


Chemical

4ichlorodifluoromethane (freon 12)

1 , 1 ,2-trichloro- 1 ,2,2-trifluoroethane

1st round (ug/m3)

3.96

11.50





RESIDENCE 70f i*

This house was sampled once, in the 2nd round. 111TCA was detected, although not atconcentrations associated with unacceptable risk. This result raises the possibility that somevapor intrusion may be occurring. However, indoor sources are also a possibility. 111TCA hasbeen detected in the groundwater plume, but has also been detected in many houses, includingthose not believed to be in the plume area and houses where TCE was not detected. This houseis outside the immediate neighborhood of the Chromatex plant and does not appear to havegroundwater contamination typical of the Chromatex plume. Also, 111TCA was not detected insoil gas outside the house. For all these reasons, vapor intrustion at this location seems unlikely.In any case, CEs do not appear to contribute significantly to risk, nor do any of the detectedchemicals.

Chemical


chloromethane


111TCA

methylene chloride

benzene

toluene

m,p-xylene

14DCB

Soil gas (ug/m3)

2.8

1.2

8

5.8

2.2

2nd round (ug/m3)

2.2; 2.5; 2.3

0.92

3.6

0.27; 0.26

12

0.41; 0.42

5.0; 6.3; 5.5

1.2

1.2; 1.2; 0.95


Chemical


acetone

2-propanol

2-butanone

tetrahydrofuran

1 ,4-dioxane

ethanol

ethylbenzene

o-xylene

styrene

124TMB

1,3 -butadiene

carbon disulfide

hexane

Soil gas (ug/m3)

100

3.2

19

*

280

1

1.3

3.1

3.7

9.1

9.6

4.4

2nd round (ug/m3)

2.0' .

17

12

6.3

4.4

21

94

RESIDENCE 90

This house was well outside the industrial park neighborhood. It was sampled, twice;unacceptable risks were never identified. Vinyl chloride was detected once, in the 1st round, butnot in the 3rd round. At this time, vapor intrusion appears highly unlikely. "

Chemical


vinyl chloride


methylene chloride

benzene

toluene

1st round(ug/m3)

7.91

2.56

5.62

11.12

3nd roundbasement (ug/m3) .

3.02

2.00

6.01

1.17

8.45

3ri round 1st

floor (ug/m3)

2.56

1.88

5.30

1.14

9.22


Chemical

xylene

1st round(ug/m3)

3nd roundbasement (ug/m3)

2.69

3rd round 1st

floor <ug/m3)

2.56

RESIDENCE 42SR93

This home was sampled once, in the 1st round. CEs were not detected, and potentiallyunacceptable risks were not identified. At this time, there is no indication that vapor intrusionaffects the indoor air of this home. This home is also outside the immediate vicinity of theChromatex plant.

Chemical

acetone,1

2-butanone '



toluene


31.35

3.52

4.57

3.84


50.64

6.00

PADEP Soil Gas Study

PADEP produced a Site Investigation report in April 2002, in which they assessed the results oftheir air and soil gas sampling. This report contained the following conclusions:

i"The results presented in Section 3.6.1 show that low levels of TCE and c 12DCE foundin the ground water were also found in the headspace air samples. This trend wouldindicate that TCE and c!2DCE are volatizing from the ground water into the air columnabove the well over time. "

"The results presented in Section 3.6.2 show that trace to low levels of TCE found in theground water were also found in the headspace air samples. This trend would indicatethat TCE is volatizing from the ground water into the air column above the well overtime."

"|T]here appear to be no significant patterns indicating any pathway from thegroundwater to the soil gas at the subsurface depth and location the samples werecollected. There may be other pathways that soil gas from the groundwater (if soil gasexists in significant concentrations) may take. There may also be other considerations


that may affect the concentration and pathway of soil gas, such as meteorologicalconditions, each compound's volatilization, and ease of transport through the subsurface.Subsurface transport could also be affected by different subsurface composition or aneasier pathway from the groundwater, such as through fissures, tree roots, sewer, andconduit."

Therefore, PADEP found volatilization from TCE and DCE in groundwater to be a possibility,consistent with EPA's view. However, a full pathway from well headspace air into the indoor airwas not conclusively established.

"[T]he elevated level of,l,l,l-TCA found in the basement air sample at R-9 is not likelyto be related to the groundwater plume. However, while Unlikely, this presence of 1,1,1-TCA warrants further investigation."

This is consistent with EPA's view that 111TCA is likely not to be completely due to thegroundwater plume, although there is considerable uncertainty on this point.

EPA Sewer Investigation

jp?A%sp.'sampiefePreliminary 'resjijis m||catewe iPresence^dthjer^^niMe^^^gtto^^îi^M^^SfiSS^JS^^M^16 following ghemicals, although this is subject to change after full validation(e.g., some chemicals might be attributed to field blanks): acetone, carbon disulfide, chloroform,bromodichloromethane, 14DCB, isopropanol, 2-butanone, ethanol, limonene, undecane, 2,6-dimethyl-7-octen-2-ol, bicyclo[2.2.1]heptan-2-ol, 1-propanol, eucalyptol, amethylcyclohexanone, a methylcyclohexanol, methyl salicylate, dibromochloromethane,

* J * * J J r-!<.%ff-"-'"";y •'••••,' 'i&'stsys-i' yimf-sf^smmisobutane, metfioxyethane, methylene clhlonde, and toluene. IMQgt! of 1oijpij£||!brQm^dichToroi&effiarieJ diferomb^j[e. . |?arb'Jon;dis!iffi4^WPC ,.2^Jut|diatê'noiunu§uai-uir'conimpnly|iriîthe^n\

^3&SZ&5i

|he;|gwef|;is>ins.ufficiently conkolled... -In thi'sfciase|teereis noigviderice th^tH^|ev^^^fc^^ ..... - as''a'signiiicant--souifee * ' ' ' '

be^related to the publie; water supplyias^mese-arevcornmon byproducts of crnorine'disinlectioiii'jj-»',v*'"',' -•<*,'- -r-"' «t'"v.-''' ,.»*,-. ^*^r-t, ••>!.;*£?'>: ;- --fci-4, ,--'-;- '•>•• - ••<"• "•;j."-~"'.> .*,;-"-.- , *'-"W-7" ;-5'!"fe,'--.^WfVf"^~-'™"**i-m fec|, recent Gonsumef Cpmdence ports'for liije^Hazletpn


itrihalomethanes are indeed present, although the reports do not idehtify^the individualtrihalomelhanes. For chemicals such as carbon disulfide,;14D€B^2-tnot immediately apparenfwhether the sewers affect the mdopr air or >indoor air are; affected |y;;a'common source, e.g., indoor use of .household product o|presence of thesechemicals in the public wat8r supply.fCHECKTHESE CHEM§;3i«fflHSft" *r , .,* '''• <~*~ ' '<?- •< ~<'''s/;'s.#'Z "*'''''* £""•£,••*<*•?* " ~ " " - ' • , ! • -, "Y;-- -;;f ^ V *»,-< ," •"• "' ' K; • Vf'"^7^^f^,^*,'™i' '»#i^kVy^^**^1'11 '*~>,^ , ^p^liîiiofcdetejnêât^s tm

iuiblicîlel/''''"'" ';s

Summary and Conclusions

Some houses in the neighborhood exhibit CEs that may or may not be associated with vaporintrusion. However, these chemicals are usually not associated with unacceptable risk; wheretheoretical risks have elicited concern, the results have not been consistent from sampling roundto sampling round (i.e., concentrations have not stayed consistently high over a period ofmonths). While some of the houses where CEs were detected were very near the Chromatexplant, others were farther away. There was a greater variety of CEs, including PCE, on FawnDrive near a suspected PCE dump. It is possible that houses in that location are affected by theChromatex plume, the PCE dump, both, or neither.

111TCA in particular appears likely to have indoor or outdoor sources in addition to its presencein the plume; it was detected more frequently and in a more widely scattered pattern than otherCEs. Furthermore, 111TCA is now more common than TCE in commercial products. It ispossible that 111TCA inside homes comes from vapor intrusion, indoor sources, outdoorsources, or a combination of these.

The indoor-air chemicals that are of greatest concern in terms of risk are usually not CEs; theyinclude chemicals such as benzene, TMBs, 14DCB, chloroform, and carbon tetrachloride. Itdoes not appear highly likely that these chemicals are related to the Chromatex plume. However,there is uncertainty associated with this, because several of the chemicals have been reportedlyused on site or found in the groundwater, as well as being common in indoor sources.

There is currently no reason to suspect that the plume extends to houses outside the immediateneighborhood of Chromatex. Homes 70, 90, and 42SR93 do not appear to be affected by theplume at this time.

Several houses yield no CEs and did not have unacceptable risks from any chemical identified inindoor air. Indoor air results were discussed for each individual residence so that the air qualityin each home can be considered both separately and in comparison with the neighborhood.

There is currently no evidence that the sanitary sewers emit benzene or CEs to indoor air. It isnot currently known whether chemicals found in the sewers may affect the indoor air, or whetherthe sewers and indoor air are affected by a common source, e.g., indoor use of householdproducts or the presence of chemicals in the public water supply. [INSERT FINAL'


CONCLUSION FROM CCRs] The chemicals most strongly associated with the Chromatexplume (TCE and 111TCA) were not detected in the sewers.

The tentative conclusions about the likelihood of vapor intrusion are summarized in.the tablebelow. Like the other conclusions in this report, they are subject to reinterpretation as the RIproceeds.

PRESENCE OF CHEMICALS IN SITE HISTORY AND DIFFERENT MEDIA, ANDESTIMATED LIKELIHOOD THAT INDOOR AIR CONTAMINANTS ARE RELATED TOTHE GROUND WATER PLUME (based on current state of knowledge)

Chemical

acetone

benzene

1,3-butadiene

2-butanone

carbon disulfide


chloroform

chloromethane

chlorotoluene

cyclohexane

1,2-dichlorobenzene ,.

1 ,3-dichlorobenzene

1 ,4-dichlorobenzene


1,1-dichloroethane

1,1-dichloroethene

1,2-dichloroethene

PADEPshehistory

,\

X

X

X

X

X

X

X

Groundwaterplume*

X

X

X

X

X

Indoorair

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

Ambientair

X

X

X

X

X

X

X

Soilgas

X

X

X

X

X

X

X1

X

Sewer

X

X

X

X

X

Likelihood

D

C

B

D

D

B

B -

C

D

D

D

D

D

D

A

A

A


Chemical

1, 2-dichloro- 1,1,2,2-tetrafluoroethane

1,4-dioxane

ethanol

ethylbenzene

4-ethyltoluene

heptane

hexachlorobutadiene

hexane

2-hexanone

methyl t-butyl ether

methylerie chloride

2-propanol

styrene

1 , 1 ,2,2-tetrachloroethane

tetrachloroethene

tetrahydrofuran

toluene


1,1,1-trichloroethane

trichloroethene


l,l,2-trichloro-l,2,2-trifluoroethane

PADEP'sitehistory

X

\

X

X

X

X

X

X

.Groundwaterplume*

X

X

X

X

X

X

X

Indoorair

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

Ambientair

X

X

1

X

X

X

X

X

X

X

X

X

Soilgas

X

X

X

X

X

X

X

X

X

X

X

X

Sewer

•

X

X

1

X

'

Likelihood

D

D

B

B

'D •

D

D

D

D

D

C

D

C

BA

A

D

B

D

A

A

B

C


Chemical

•

trimethylbenzenes

vinyl chloride

xylenes

PADEPsitehistory

X

Groundwaterplume*

X

X

Indoorair

X

X

X

Ambientair

X

X

Soilgas .

X

X

Sewer Likelihood

C

B@

B*List is minimal, representing several available rounds of data, and does not include everysampling event. Therefore, a Chemical's absence from this list does not necessarily mean that itis absent from groundwater. • • .A = Chlorinated ethenes and ethanes, present in both site history and groundwater, usually absentfrom ambient air; considered most likely to be connected with vapor intrusion.B = Chemicals with a possible connection to site history and/or groundwater sampling, but whichhave low frequency and/or concentrations in groundwater, and which often have other possiblesources. These chemicals are considered probably unconnected with vapor intrusion from thegroundwater plume, but there is considerable uncertainty associated with this tentativeconclusion.C = Chemicals considered unlikely to be related to vapor intrusion, although a potentialconnection cannot be rule out.D = Chemicals without a current obvious connection to site history or groundwater, which arestrongly suspected to be unrelated to the groundwater plume. However, some of these chemicalsmay have been detected in soil gas or sewers.@Although vinyl chloride is a chlorinated ethene detected in both groundwater and indoor air, itsdetections were not co-located. The only detection in indoor air was well outside the vicinity ofthe Chromatex plant. Therefore, vinyl chloride is rated "B" rather than "A."AAlthough 1,1,2,2-tetrachloroethane is a chlorinated ethane, it was detected only in indoor air andis therefore rated "B" rather than "A." '


Comprehensive Analysis of Indoor Air at Valmont TCE ... · the eastern side of the neighborhood. Air from house 51 'has also contained PCE and 1,1-dichloroethane (1 IDC A).: PCE at

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