SF_XFS_WRGrace_3-12_LINES.indd 1 3/6/2012 2:34:15 PM

',4.DIOXANE

WRGrace

THE SUPERFUND PROGRAM prot.m hwman health end Ille ""wl'OlImelll by IIIIH:fIjf'Jtlnr and de(IIIJ"r vp o(ten-abandotte<i hazardowl """,te JIteJ and engt1iIn, cam/mUl/lleo threw,"","! the precen. Many'" th ... ,iw are CIlm~I"" and "..,d IOIOf"Wm c/eanvp oxtianr. TIlon rerpOll$Ib/t (01" CClltClllhl<lt/oll crt held N~le (or c/ea""P <mfr. EPA J!IWeJ C<I rerum preyl<l1IS!y cclllllmlnate<l land and Jl<'ull<l'wmlr

C<I ~rodllaw. WHo --_. __ ._-----_. SITE DESCRIPTION AND BACKGROUND: Tho POJrpoo& of th~ foa ,iIoeI II;"DO U1 ...... q_' for .-..Idom:o; abo," l,i do:<ano, wNdo ~ I COMlminant 1ho! wu bnd III tho W.R. G..., Sitzo. 1,4<ic>xAno ~ .. i-dJdrioIlOivonithat_ rrst ~ n ""un_ 01: !he W.R. G ..... SIlo .. 200/i. Sioce that time. the ErMrorll"l'lOl"ltll _n .... '1<)' (EPA) and _u_ Deportrnonl of

En¥tonm<ntol ~n (H"OEP) h ..... .-.<iund Cnao 11:> monl1l:>rfor It. ~ ohould too .-:I1IIot th, 1,-1-cko<ano ..... I,buod do natewoed BWI aaq>I>bIo riokrup. In .odilian, theAdon war DiItrict (AWlJ) ~UoIHIi"loncl mo .... rInf!he School _ and _ pLmllc_lIJ~woIl. for 1.+&naIne. Th ............ 1IJu, .. tor_ 1i101:tn. 1,-1-cko<ano 1 ..... <10 notsaed 111, MaaDEP ndrWq_pkll .. of0,3 pom por blbon (PPb). ThI' fact _ ecpIoi .. thil below n ""' ... __

"Tho W. R. G..." (km Plant) ~ Site io Iocft<I .. 1I1e T"""", of _ ond Concord, ~_ ond l1li_ ....otr_~ p....,... .... 1IIe ll1OO"L Tho W. It c;,- p~io WII d ofljl...,...m.t.ly20i0 aa..oflond ...... WC-.luiooo_ ....... ond ... ~-,

W. II. Grw:e..,.nothe..-vn 1954, ond apnIionI oI:thew. R. Grooo~ncbledthtproducdonof_ oil used,., "'""" o:oncro:IO and .,...,:c chernIcoII!, <ontII .... ....... ~ '""'" ,""'lido, ond .,...... and jliooIK: bIIItory _ .... L W . __ and.,t;ll"icluotrlli_

bn 1heoe op<I_~were"'" of .................. ......... andwere buoiod;, lfilrrnoronoito inobIri~ i..a"od­/I. .... 1TiIIi~ _ 0I:!he Gnoo:z!Ot.;, 1m.

WHAT IS 1,4·DIOXANEr 1.4dcoane ~ I deer ~ tho! tidy dIoooMo and .,..,.. <jIOd<iy;'_. Ora o:IiJoan<Im._, ~d"," rooot ... ,.

..... tho -... and ....... ..,., .... l II ...0 prWn""" • ooMm: .. 111, 1TiIIi.tacan of cIIorrbio; • 1 Iabomory ...,.-<:and.IStIbIIIzerond .... odhesi¥e. 1.+<I_~ ...... praerJ: .. v- lrIiiIunb ;, co.nria, de ..... , ...

ft ~I',,~una.d_ _ E .... oonmo .... 1 P,." d," - .-....

aro:I r.n-. Goo ,,,,,"'...,cos _thoI: 1,+<1"_

~iIoOy'" too cwd...,.iII:"' ........

WHAT DOES CANCEIlRISK MEAN? Crar riook io!he ",adlOllial" or IikitionoI ........ Iioo, of... ..,.........,. tIooI ""'I' too oIIooct.o:i t,o • cw d.".. " oJoctance '-", Ifetrne. .. OIher-.ll, .. --....:I arar riookoFl ;'Imib (1 ;, l.oolOOO)-.Id .-tho!1hoto ~ .pabobitJof __ ....... _ ...................

.. I popoAtIonofono .... poop.. Thotam 'hJalOlltol'

........ '" rtIks _1toe ~an<W"""ecpeo leiad t,od ......... .. ............. oFdoo,.iIO. EPApid'Iy_ a<tion.d. SR""",,,,!he iadlOllboi <an<!>" r'ok io ~ .,..., 1 .. 1(l,(XXl. EPA IIbo InIo:o OCIX1iJrrI: oIIiHpedIIc 1ict:n -'~lIIeneedtorldeorol4>ICIIon.Farewnpie. EPA llichtlab...., _m.p.dic~tho!aqoDo: ~ .... boIrc ..,.... by....".....,.. cIo::horft '" ....,._ .. .:.aq .............. "'0CII0ni>rpnd­__ io.....o.o. EPA""" lolo:o InIo:o -=om urartoirrtiooo """ Iho riook __ <lmnniq !he need i>r • -.... don. Fareamplt. EPA mIgtr::!!Ie I"m OCIX1iJrrI: Iho ~ .. il5llrIIIIirc ............ "ikoud' ~ and :..u-;,,;;, <Iocioq_doooq>_ io_

.......... ,_ ......... _ ....... _ ... ~01_ •••• -__ .... _.~".'_"~

KET CONTACTS,

...... ::1< GOLO ...

EM N .... EnJl.nd ~~M.n.,.,.

(m) 911·1448 I·Id.n.d.crick··j>Llov

.A.AH WHITE

EM N .... EnJl.nd Commu"il)' InYOlwmont Cocn:/I""ror (617) "1·1026 wI1lte ....... haepl -tOY

GENERAL INFO,

nA ".w ."GLA .. D

5 .... ,1 OHico S~" .... Suite 100 B.,ton, MA 0210~·~~12 (617) "1·1111 www .• pl .• ov/re!lonl/

TOLL·nEE CUITOM .. Ii.VICIi

1~88-EPA·7Hl

LOA ... MaU AT,

www··PI .• ov/ne/ ,u peri.lnd! ,IIM/lrl<, .. ,ton

Murch 2012

SF_XFS_WRGrace_3-12_LINES.indd 2 3/6/2012 2:34:26 PM

SUPERFUND I HAZARDOUS WASTE PROGRAM AT EPA NEW ENGLAND

HAS 1,4.DIOXANE BEEN DETECTED AT THE W. R. GRACE SUPERFUND SITE? (SEE ATTACHED FIGURE) Yes, according to the 2010 annual groundwater report, 1,4-dioxane has been detected at the W. R. Grace Superfund Site. The 1 ,4<lioxane concentrations detected most recently in the Northeast Area range from a low of 0.11 parts per billion (Ppb) to a high of 2.1 ppb. Located on the southeast portion of the Grace property, in groundwater flowing away from the former Industrial Landfill, 1,4-dioxane concentra­tions have ranged historically from a low of 1.5 ppb to a high of 36 ppb. Note that 1,4-dioxane in the Northeast Area has migrated beyond the W.R Grace property line, see attached figure.

HOW FREQUENTLY IS 1,4·DIOXANE SAMPLED FOR AND ARE THE ACTON WATER DISTRICT WELLS SAMPLED FOR 1,4·DIOXANEl W.R. Grace collects samples from numerous ground­water monitoring wells throughout the Site annu­ally. Grace also collects water samples at the effluent discharge for the Northeast Area and the Landfill Area groundwater treatment $)'Stems on a monthly basis and analyzes them for 1,4dioxane, voIirtile organic compounds (V0Cs) and metals. Also, since 2007, the Acton Water District periodically samples for the pres­ence of 1,4dioxane in the Assabet and School Street Welffields.

The most recent sampling of the Acton Water District wells was performed during September 2011. Untreat· ed riW{ water &om the School Street and Assabet wells IMlS sampled for 1,4dioxane using EPA drinking \Yater method 522. After combining duplicate results by aver­aging; as recommended by both MassDEP and EPA, all results were below the MassDEP drinking water guid .. line of 0.3 ppb.

DOES THE ENVIRONMENTAL PROTECTION AGENCY (EPA) HAVE AN ENFORCEABLE DRINKING WATER STAN· DARD FOR 1,4. DIOXANE?

No. Currently. EPA has not set an enforceable drink­ing water standard for 1,4-dioxane. Enforceable Federal drinking water standards are called Maxi­mum Contaminant Levels or MCLs. However, EPA has developed a nan-site specific Federal guideline for 1 ,+dioxane ofO.67 ppb, calrulated using a cancer toxic­ity value developed by EPA in 2010. The levels found at the School Street and Assabet wells are below this nan-site specific Federal guideline. Additional informa­tion on how EPA evaluates potential risk and how EPA defines ·acceptable risk· is provided below.

DOES THE MASSACHUSETTS DEPARTMENT OF ENVIRONMENTAL PROTECTION (MASSDEP) HAVE AN ENFORCEABLE DRINKING WATER STANDARD FOR 1,4.DIOXANEl No. Cunrent~, MassDEP has not set an enforceable drinking water standard for 1,4- dioxane. Enforceable State drinking water standards are called Massadhusett> Maximum Contaminant levels or MMCLs. However, MassDEP has established a state drinking water guid .. line of 0.3 ppb, based on cancer risk and EPA's cancer toxidty value, for consumption of drinking water.

WHY DO EPA AND MASSDEP HAVE DIFFERENT GUIDELINES FOR 1,4.DIOXANEl MassDEP and EPA guidelines for 1,4-dioxane were developed for diffenent purposes and each agency uses different assumptions when calculating the respective guidelines. MassDEP developed their 0.3 ppb guideline to protect people who might be exposed to 1,4-diox­ane from drinking contaminated water. For purposes of this guideline, MassDEP assumes a person 'WOuld drink 2 liters of contaminated water per day CNer a 70 year lifetime.

EPA used its 1,4-ciioxane guideline to determine if there is an unacceptable risk to a person who may be exposed to contamination &om being on the Site. EPA assumes a person 'WOuld drink contaminated water CNer a 30 year lifetime, induding 1 liter of water per day for a young child and 2 liters of water per day for an older child or adutt. Unacceptable risks may trigger

1,4·DIOXANE

EPA to require additional regulatory evaluation and/ or clean up actions.

EPA evaluated the concentrations of 1,4-ciioxane and compared them to the EPA guideline and determined that there are no unacceptable risks to humans from the presence of 1,4-dioxane at the Site.

WHY ARE MASSDEP'S DRINKING WATER GUIDE· LINES NOT ENFORCEABLEl ~Enforceable standardsW are those that have been formally promulgated in regulations. EP~s Maximum Contaminant levels (MCLs) and Massachusetts Maxi­mum Contaminant Levels (MMCLs) are the promul­gated federal and state standards, respectve~.

MassDEP's drinking water guidelines are recommend­ed levels developed by MassDEP's Office of Research and Standards (ORS) for contaminants that do not have established MCLs/MMCLs. These guidelines have not been promulgated in regulations.

HOW ARE MASSDEP DRINKING WATER GUIDELINES DEVELOPEDl The MassDEP Drinking Water Program (DWP) eval­uates all drinking water sample results against enforce­able Federal and State standaros (MCLs and MMCLs), or against guidelines created by EPA or MassDEP Office of Research and Standards when no Federal or State MCl is available.

However, Federal or State MCls have not been estab­lished for some contaminants that are required to be tested under the Safe Drinking Water Act (SDWA). As a result, MassDEP Office of Research and Stan­daros has developed guidelines (or ORSGs) for these contaminants.

These guidelines, or ORSGs, are established using risk assessment methods consistent with those used by EP~s Office of Water when setting guidelines for chemicals in drinkingWcrter: ORSGs are developed using EP~s toxicity information, when available, and assume that an adu~ ingests 2 liters per day of contaminated water throughout a 70-year lifetime. When there is no toxicity information available, information is sought from sdentific literature to support derivation of guidelines.

SF_XFS_WRGrace_3-12_LINES.indd 3 3/6/2012 2:34:27 PM

SU~EIFUND I HAZAIDOUS WASU "OG.AM AT HA I'HW ~NGLAND 1.4·DIOXANE

In order 111 iIril ~ 111 cot .... Lb iIIIiorII. of card­nopnic chmiab _ m..th II poa:bIe, 0P.SGs for U- dIemica't .. ,. ." .... ~ I'6ItiM 0601'

riIIr. (8..CR.) fI one in one miIon (1 in 1.000.000), (II" ~ the Ioro¥est pndbI ~ Ih* (l'Ql.).

COM'...aHON Of l.4-OIOXAHI COHaNTltATlOfIS IN GIIOUf<OWAn~ .... o OIllIIliHG WAll. TO .LVlISOf_

0i\SGI: _ not ~ for .If*lx: '' ot' upoan urwio but re ~ 10 IoCII WIll:/' ~...:I

the pnenl po.tit. A dau ~, fl1he proaa uted to derM 1hes. va ..... an tit found in tht GUdtt 11:1

the ~ «T~ ~ In Haaad'iiJ.mts ~. QuctionJ rqardirLa tI'it MusOEP J-idIIi""" i.or 1,4-dicNne InouIcI b8 directed to Oiano ~ I/'Q In ORS 11: "7·55~ 1158.

HOW HAS EPA CALCULATED THE POTENTIAL CANCER RISK OF 1,4.DIOXANI! AT

THE GRACI! SITIt EPA ~u aJIId.Ided. ~ m :, ' iCLiit flthe WIOIr risk tom l.+<fiOlWlll It thl Q.ce lite. EPA LBeC! -..err mmter'II.M n.tpcdk copoan em. mdeI. In ltis ~ EPA -..:ned that ..... IrdYid­l1li 'MJUkI <h* ~ ."..." from "It. _

~ --. ~ period ~ '>-"1-' )O'IC chill! ...:I 21 ,-.s ., .... dOw ~ or ..... EPA ., a:u.med fc • )'OIq chid -.ad .mit 1 h!rol"walI!rPlfdlrtnd .... oIrJIrc:Hdor 1flft'Nl:Ud .mit 2bs 01"_ per dIr. The COI ..... oaltial'l of 1,~ in , ..... fIiII ~ ....... __ 1tis ~ period _ -..ned 11:1 be • b Ihe N&fI­enwclib .Iion IiM1d It U. 511e ( U ppb). ltlhodd be naWl1hat b hWWIt COi ... LtlO!tlonI of 1,-4diI:» IIIIe (36 ppb) 'MIn' b.nd on 1M Gr.ce ~ IU tt-.t CD ... ,bationJ brpld 1tit GrIet ~ II"t I'ICNf signifantty k1Mr 1ti .... 1tiet used by EPA In thiI slbHped!k: risk. _=1. it EPA has cjt'llll iidl'led 1I1at e.oen ulins"!he rTIIXIrvn dctectecj concentmion d l,4diawJe (3' ~pb~ ~ conwnlnate:lrroufld. wm:r does not pose In unLlCCie~ anoer risk to humlll ~eihh thlil. _uld I"IIIaIIILIitate III EPA dean up ldion. HOWWIr, dUll to UMO:IIpIlIo. ri!lc:s fioom other mntaminIntI. ~ lit 1I1e QU!! Site II ~I*na:~.

-

-WHAT IS THE POTENTIAL CANCER RISK CALCULATED BY EPA AT THE W.R. GRACE SITU The CIrIO!:I" rille eaim&Ie _ the 3' ppb .-anun deo.mred 1,4d'olrilne w"""bllion is S in one )udoed IhousInd (S in 100.000). ThS iI wiItin ff'A'r .azpta!lIe risk ...... It _ dedded to ... 1he 36 ppb CDL'aNJ'ation beause this _ the hi&hBt dDt­

IIIIe COl ..... iImion b.r.d and it re~ I ~II

worst elSIe --..rIo. It Is allPO Important to I1C.IIie ht \his risk. WIS ~ baed upon the highest ~ tntion (36 ~) d l,4diawJe m the GrIce pr0p­

erty and thIt because CD """b mons in croundw*r ~ the Grw:e property line;\/'e liaMantty It7tm; the poterrtili carJCa' risk would also tie ILipQ/Tll)' lower. In addition, no me is dTiking1i1e p!I1~r wIWI! the l'iptd'iCDWII! CD ICeIrtraiions __ found

on 1I1e Graoe property.

HEALTH EFFECTS OTHER THAN CANCERI The wlCeI,baticn of ',~.tthe 5itt= do not pout ~i!! i"iOI"\QI"iC8' rlIIcs. N. II'lUdl Nat-

<LOt""' iUtioi. r,-- than 1,000 ppb}. <kriq _till" contal". C 1.~ .. ~ QI.III!..,. b thek-'~

for adoitioraI i'" "idol, .bout the WA Grwr Si'z &0 10 h i:oIoroWw: 'MibsU: -~/rw:/II..tprinVft¥~

ADDITIONAL CONTACTS: ,.",JarI1r;\'/_.., ProjectM.n ..... MA Dlpartrntrrt ~8w' 01" .. otaI Pi'OIiIiC1icn (,,7) ~<MS60 jIN'KIr~ur _M_ Acton Watu Olnrict: (778) 20-9'07 m~OYII

o.-dont abcIut MlllDB"'11.4-DlmIInIi G.i1dr6lE

01_1'1IIIIII'I"I MA o.p.-trroen'i o(~ Pn:rrectIon (,,7) SM-11S8 "-

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North Lagoon Wetland

Northeast Area System

Sinking Pond

Industrial Landfill

Landfill AreaGroundwater Treatment System

Christofferson Drinking Water Well

Scribner Drinking Water Well

LawsbrookDrinking Water Well

Assabet No. 1ADrinking Water Well

Assabet No. 2ADrinking Water Well

0.134

0.281

0.190

0.228

0.115

0.152

1.74

0.2121.92

20.2

1.51

3.84

35.7

18.9

34.7

1.65

1.65

1.17

0.51

0.987

1.8

1.43

2.12

1.83

2.12

0.1090.169

0.175

0.385

0.11

2.07

1.87

0.439

1.54

< 0.2

6.56

0 0.25Miles

´

Route 62

To Route 2

2011 W.R. Grace Superfund SiteSampling Locations for 1,4-Dioxane

Assabet River

Legend

Well TypeMonitoring WellExtraction WellDrinking Water Well

Concentrations, in ppb

0.3 - 3 ppb¿

¿ 3 - 36 ppb

(

*

)

0.3 ppb or less¿

W.R. Grace Property

0.00