Epa 6 Secret Report

7/30/2019 Epa 6 Secret Report

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DRAFT DRAFT

Sud; ' Mi:ud Waste Ludrill

Grouadwater Moaitorin& WeD System

u ti Procra- Onrr iPt Review

12112/07

On Malcl11. 2007. Ci!i= Ac:tiou NewMcxiw (CANM)_ted hat information pertainingto g round_ mooilO!ing for the Sandia National Labor.IOI)', New Mexico (SNL) Mixed

W'ISI< Landfill (MWL) be "'; 'wed by the Environmental Prolec:tioo Agency (EPA). Cit i=Action asked th. . written information and • CD they provided be forw8rded 10 the EPA NationalRisk Managellu:nt Resean:h Lahomol)' N R M R L ~ They also_ed haI NRMRL review the:

November, 2006, New Mexico Environment lXpartment (NMED) rq><>rt by Mr. William Moats,

el aI.• entitled. "Evaluation of the Represcntativeoess and Reliability of Groundwater MonitoringWell Data."

Citizen Aetion·s request stated that they believe the monitoring well network cannot provide

reliable and representative water samples for numerous reasons. and that the November. 2006.NMED rq>Ort contradicts earlier rq><>rts by NRMRL staf [ They also pro";ded DumeroUS

additional e ~ m a i l and telephone correspondence with groundwater information relating to the

MWL .

After considering CANM's request. EPA Region 6 conducted the: review of his infonnation as

part of our OV"';ghl t;esponsibility for NMED's federally authorized RCRA program. The

NRMRL wu consulted on various tcchniw pouudwatcr issues, however.

We did not conduct a rigorous teclutical review of he November. 2006. NMED report because

the State cODduC1cd their analysis in a manner similar to the methods used by NRMRL in aprevious e v i ~ ofLANL data. Further. because the NMED has already directed SNL to replace

a number ofMWL monitoring wells due to factors such as well screen corrosion and dropping

water leVels. at this pow we prefer to conduc1 detailed evaluations on data from. new wells based

on groundwater monitoring objectives aod data requimneots, should that become n=a r y .

We reviewed the overall MWL grouodwatcrmonitoriog system in order to detemrine its efficacy

in detecting contamination. We reviewed weU locations. depth of wells and well screens, purging

and sampling methods. downhole videos. and analytieaJ resul ts.

The original mOnitoring wells were installed based on geology and regional and local

groundwater flow known at that time. Population growtb and changes in land usc in the:

Albuquerque area since this monitoring network was initially installed has probably altered flowd ~ n and aquifer levels due to increased pumping. Further study (more data over time) has

improved the understanding of geology and groundwater mechanisms. These factors, combined

with the age and degradation of some wel15, has led us to o m m c n d updates to the monitoring

methods and oetwork. which the NMED has already begun to implement.



The scope of our review encompassed fundamental aspectS ofthc: groundwater monitoring

system and the effectiveness of upgrades to the existing system involving the placement of new

monitoring wells. Specifically. we reviewed information pertaining to: (0 ,he MW l conceptual

hydrogeologic model and whether the eooccptuaI model is consistent with published infonnationand field data; (ii) published information on regional groundwater flow directions (Santa Fe

aquifer) and stresses on the regioo.a.l system; (i i i) site specific information on the locations of

existing MW L monitoring wells with respect to flow infonnation contai.ned in SNL reports; (iv)

well screen depths and intervals; (v) consistencY ofweI! depths with the site conceptualhydrogeologic m o d e ~ (vi) groUndwater flow directions and gradients in the two main saturated

units ( te , alluvial faD and Rio Gronde strata); and, (vii) possible improvements to the monitoriJig

well netWOrk including potential new well locations.

BackgrcuDd .

The MW L operated from 1959.to 1988. It is small. 2.6 acres., and the landfiU bottom is located

more than 400 feet above the Regional aquifer. The MWL bss "fairly wcl!-documented

inventory ofcontents comprised mainly of laboratory wastes. Precipitation for the area is less

than 1Q incheslyear and there are no significant surface water reatl..ll'eS in the- site vicinity.

CANM:

NMED:

EPA:

The MWL should be a regulated unit. not a S WMU.

Solid Waste Management Unit.

No comment. in State court.

Th.decision to trest the MM '" , a SWMUwu original!y made by EPA in 1993 befure thi>site's regWllIory responsibility passed to NMED in 1996. For EPA to revisit that decision '" this

late date would serve no useful purpose since we believe the site has received adequate attention

through the corrective action process. In addition. since Citizen Action brought this matter

before the State Court·of Appeals in October, 2006. it should be allowed the opportunity for

resolution through the-State administrative and judicial processes.

CANM:

NMED:

EPA:

The p u b l is not afforded opportunity to participate in MW L decisions.

A d e ~ e .Continue f u r t h ~ discussion with NMED.

in general, EPA believes that NMED has provided adequate public notice and opportunity for

participation in regulatory activities related to the MWL. More specifically. NMED has routinely

2



placed MWL documents on its,website and numerous opportunities have been provided for

forinal public comment on MWL proposals and plans. For example, the dec",ion 10 place acover over the MWL, wtUle maintaining long term monitoring. was made after several yeari of

public meetings. Study9 and diKussion. Participanb included. formal Citizen's Advisory Soan!

(CAB), NMED, DOE, SNL, various indcpeudcnt tccluUcal exptlts, as woU as local inletOStedcitizens. The EPA was au ex officio participant in the CAB. Several possible scenarios werediscussed before the tiDal cover and monitoring plan were selected. 11tc purpose of the cover

was 10 toduc:e t)le possibility of"""Wninalion tuehing tbc groundwater through mcclumismssuch as erosion. WIlIer infiltntion, and animal intrusion.

Citizen Action bas also demanded that EPA dln:ct NMED 10 release documents such as the

"Ted!Law repotI." Citizen ActioD is a party to the lawsuit con<:eming NMED', release of hatdocumeni. and this matter ia abo CUI'TetI1ly being addressed through the New Mexico state courtsystem. lberefore, EPA considers this an issue of State law and we wil1 anow it to be resolvedthrough tbc State judicial proc. . ..Concerns about specific issues shoukl be raised during the public comment period and addIessed

through the . t e channels ofNMED', fedctaJly authori=! RCRA program. thus utilizingthe proper Stale administrative andjudicial processes. However. since the MWL is currentlyaddressed as a SWMU in the facility pennit, the nature of the permitting process does not r e q u i ~specific details ofevery indivicfual decision to be opened to public commcnt. Instead. specific

concerns should be addressed during gCoem public comment pcrlods. such as that for the LongTerm Monitoring aDd Maintenance Plan,. which is currently opcu for comment.:

CANM: Wclls should use a low flow purge and sample method.

NMED: CUlTCIlt sampling method is adequate and representative.

CurmtI sampling uses Bennett pumps, with purging tales of approximately OS to 1.0 gpm . Thepumps abo utilize. small valve to obtain volatile samples. There is no indication that the MWL

wells have been dama&ed by this method. The facility is sampling appropriately and doing thebest they can under tbc existing conditions. The NMED has done their own sampling to see thefield C9Ildilions and obtained the same results. It is hoped that the new wolls will have b e _screcosand volum.eofwatet since thc wells don ' t producc as well as in the past. The NMEDrosy look into difI'e=Il pumps but must weigh ifit', worth the expense to the facility. .

EPA: Continue further discussion with NMED.

"Low floW" is considend to be a flow rate oflC$S than 0.5 l.Jmin (0.13 gpm). The purpose for

low flow purgioa is to minimize the volatilizatioD ofVCC,. reduce turbidity wroch may givemore Rliabte results for mctab" and also to miDimizc the possibility of damage to the well screenor sand pack. H o ~ c r . the purging and sampling methods must be appropriate for the geologicand well conditions. Although EPA gmerally J'C1;ommeods that facilities try to imptemenllowflow techniques. EPA Bulletin No . QAD023. " L o w ~ F 1 o w Purging and Sampling ofGroundwater

3



Monitoring Wells," dated October 15, 1997. states that. "The low·flow pw-ging and sampling

method is not appropriate_for use in all hydrogeologic regimes, and particular groundwatermonitoring well designs may make the method unsuitable ....... 1nerefore. we ruommend that

NMED consider use of low flow pumps, if conditions warrant Additionally, ~ intend

observe aD upcoming sampling event to observe field conditions..

A 1996 study of several monitoring wcUs at Sandia (S.S. Collins and G.A. &;Iey) found thatVOC samples in two oul of four wells wet< affec:t<d by higher pumping ra!<s compattd to du:low-flow purging method. These tests were not conducted at the MWL. 1n a phone conversation

with du: Iletw:It Co. (Amarillo, TX) pertaining to the ability of heir pumps to ounduct low,.tlow

purging and sampling. du: company said that • low flow technique could be performed by adding

a specific piece ofequipment to the pump to reduce the flow rate enough to meet the low flow

purging and sampling requirements.

;."'" Wben using the low flow purging method, du: facility sbould be careful in detennining wben du:

.a groundwaIer panmeten bave stabilized, espeoiAIIy on wells with lonser screen lengths and larger,= diameters. Historical information from past purgings should be evaluated in determining du:

1 ~ i tabilization of ho groundwaler parameters.

__ Spud ofGroUlldweUr il l t i t . r .. Aq"ifos

....~ CANM: Groundwat., flow i$ 001 adequately understood and pumping . . . . . are needed.Usc of he average value ofhydraulie conductivity measured in three wells to calculate rate of

groundwater travel is incorrect.

NMED: Flow is adequately understood.

EPA; Continue further discussion with NMEO.

Regarding the AF aquifer, the typeS of data acquired here 00 grounclwatcr velocity an: typical of

landfill sites in Region 6. In tho AF aquifer, a pumping test wu performed on MW 4 in 1994 on

both du: upper and lower sc:reens. An inflatable packer wu used to bydrouIica11y isolate theupper and lower-screened intervals. Each screened interval was pumped wbiIe the other__intczval was isolated.. Results indicawi that there was DO drawdown observed in either

and then: was also no drawdown in adjacent observation wells. In 1994. monitoring wells MW1·

4 had the wa i t t levels monitored using presNre transducers during purging and sampling o(the

wells; hydraulic conductivity values were calculated from the drawdovm and recovCl)' data.. In

200 I, slug tests were pcrformed 00 the AF aquifer wells. From these tests. Sandia calculated theaverage tinear flow velocity for the AF faeies at 0.17 ft/year. However. actual flow velocities of

contaminated plumes an: often qujte a bit higher than calculated average velocities due to aquiferheterogeneity and prcfened paths in the aquifer. for x a : m p l ~ when reviewing the historicalnitrate contamination found in the AF aquifer wells (BWI, MW1, MW2. MW3) .... note that theacruaJ flow velocicy must be greater than the calculated value, otherwise the elevated nitrate

would DOt be found in all the AF aquifer wells. Note that this assumes the sowce for the DWate

is to the east-northeast ofthc MWL, as claimed by Sandia.

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EPA m:ognizes that there is ample published docwnentation on gradients and vc:Jocities for the

Santa Fe aquifer for regionaJ as5C$sments and local assessments when available. However.conceming the ARG aquifer at the MWL. the flow. velocity is less certain due to the fact thatthere is only one well ~ n e d solely in that aquifer, MW6.

CANM:

NMED:

BodgrolUrd WtlIs

Two beoI<ground wells are needed, one in each aquifer.

One well in uppermosl 'aquifer,

EPA: Only one J>ackground well is needed and it should be in theM facies, which isconsidered the uppmnost aquifer under RCRA This well shouJd be located on the eastern. upgradient, side of he MWL.

Low Level TritiumAnllipis

CANM: Low levellritium analysis should be don. at all wells. Wells should be installedwithin theMWL

NMED: Not necessary, sampling is now done for tritium and levels are below theMel.


W _ sampl<s an: aiI<ady tested for lritium and results are below the Federal drinking water

s1an.dard (MeL) of20,OOO piCIL, This analytical m¢>od has. repor!ing limit 0(200·250piC/L. The Low Level with Elec!rolytic Enrichment (LLEE) method has a detection limit ofabeut 03 pCiIL. Tritium is . very mobile constituenl in groundwa ... and may be a good tllICer

fur contamination. The NMEDhas

successfully,used the low level analytical method at LANLfor several years and recently used it for samples-at several wells at Sandia. Therefore. we:

recommend that NMEQ consider use of the low level tritiwn analytical method at the MWL. atleast periodically.

The landfill inventory indicates that ttitium-contaminated material was placed ,in the MWL untilits closure in 1988. Approximately 204.000 gallons of tritium --contaminated water were reportedto have been disposed of in the Mw.L in 1967.'However. since tritiwn has a half-life of only12.3 years. and several dctadcs have passed since any waste was placed io the landfill. it isunlikely thai: a signi1icaol amount of tritium contamination win rucb the deep aquifer at this

point.

Drlllilfg Wdis w.iJltin LandJiU

CANM: Need wells within the- MW L to.define ··hotspots."

NMED: No.

5



EPA: No.

Detection monitoring wells are normally located around the perimeter of a landfill. A weU inside

a landfill would not be part of a monitoring well pelWork to detennine if there are releasesoutside the landfill. Drilling through known q>ntamination would also increa5c the chances of

,cross contaminat ion between shallow and deeper zones and woUld pose a risk of creating a direct

conduit for contamination from the surface to the aquifer. We recognize that DOE bas placedgroundwater monitoring wells at other sites inside waste management areas (e.g.s Savannah

River); however, RCRA regulations do no t require groundwater monitoring within a landfill.

Instead, the groundwater detection monitoring wells should be located at the point of m p l i a n c c : .which is the hydraulically doVlngradient edge of the unit or waste management area. Further.because of the MWl.'s smaU size (2.6 acres). we do no t recommend ~ wells within i t

DriJling.Methodsfor We111nstaUanon

CANM: Drilling meth09s (mud) have compromised all wells.

NMED: Wells were adequate and representative.


The preferable drilling method for purposes of groundwater sampling is the ODe that introduces

the (east amount of foreign matter into the aquifer. fOt' both mechanical ( i . e well damage from

pore plugging) and chemical reasons. ~ h fa<:ility should evaluate and propose the best

method(s) based. on the site geology. We r e c o m m ~ drilling boreholes Without using bentonite

or organic additives within screened intervals. Additives may be used in interVals above the

target monitoring zone if telescoping casing constructions are used and the bole is a d e q ~ l yc l ~ before drilling the final .footage within the interval to be screened. The facility shouldminimize the time between drilling and Well development

We expect that installation of new wells and the subsequent ne w data will alleviate this coocem.

In the real world. bowever, drilling and sampling wells is never "perfect" since unavoidable

difficulties are often encountered. The facility is expected to use proper methods and do the best

they can under the existing circumstances and understanding of he site geology.

Aquift , Cltaraderislics

CANM: A pwnping test must be designed to thoroughly characterize and measw-e the

speed of groundwater travel in the productive (ARG) aquifer.

NMED: It is appropriate to sample the uppermost saturated zone. the AF Facies.

EPA: Continue furthcr discussion with NMED.

There are two distinct aquifers at the Mixed Waste Landfill. the alluvial fan (AF) and the

ancestral Rio Grande (ARO). This distinction is evident in the clearly different potentiometric

6



surfaces for the two units. The AF aquifer has very low average hydraulic conductiv ity (1 .81

ftlday) and appears to have some beds with vertical hydRulic conductivity low enough to act as

confining beds. It appears that the ARG facies is more productive and that wells screened inboth ",nos willlikeJy be ·controlled" by the ARG facies. ' . •

The flow directions are different for each aquifer. The AF aquifer flow di:reetion is to the wm..southwest (based on our review ofover IS ya.rs ofdata), while the ARG aquifer flow directionis to the w.st-northW<Sl (based on USGS infonnatioa and the Sandia 1990 to 2001 Groundwater

Reports). We also ootod that elevatod nillalc (4-5 ppm) is foUDd in the monitoring _ l i s

screeued in the upJX!Imwt portion oftbe AF aquifer, but iJ not found or is in much lower

concentrations in the wells (1-2 ppm) screened in the ARG aquifer.or wells screeued in bothaquifers.

CANM :

NMED:

EPA :

Wells in the ARG q " i f ~Wells should be installed in both the upper and lowor aquifm

Wells only needed in the uppermost aquifer.

Wells are only n ~ in the uppcnnost aquifer.

Additional monitoring wells.,., not needed in the deep ARG aquifer at this time. The AF facies

is considered the "uppennost aquifer" or satw"atcd zone under ReRA and is where contaminationfrom the im!dfill would be foUDd initially. We recognize that the AF facies bas very low

coocluctivity and is unlikely to be . . . . . lOr production purpose>. However, ifcontamination is

found in the AF filcies, then vertical deliDeatiou of conraminationwould be requirod by installing_l i s in the ARG aquifer.

N_o/Wdb

CANM : The MWL needs 25 wells.

NMED: One background and two downsradient wells needed.

EPA : Continue further discussion with NMED .

We recommend that the Mixed Waste Landfill have two or three detection monitoring 'W'CUs at

the urul's point of t:ompliancc along its weslem boundaty. TIIC wells should be fairJyevenlyspaced and located to intercept potc:otiaJ groundwaler releases in the uppermost aquifer. the AFfacies. Two oftbcse wells should be rtpJacemenu for wells MW I and MW 3 .. If contaminationfs found in the Ai strata monitoring wells. tbeu vertit:al delineation ofcontamination would be

requ;,.d by installing wells in the ARG aquifer. W. also recommend that NMED considerinstallation ofat least oue additional well to the north or northwest sinec it appears thegroundwater flowdirection may take. more IIOIthmly din:ction as the City ofAlbuquerque

continues pumping whid! is causing dnIwdown of the Regional Aquifer: .

7



The NMED has ·already directed DOElSNL to replace MWI and MW3 with MW7 and MWS,

reSpectively, along the western boundary of the MWl at the point of compliance in addition to

replac:mg aWl as the background well on the eastern side. Additional wells and exact locationsare still under negotiation. Once i n s t a l l ~ we would prefer to see new wells sampled s c m i ~annually or quarterly, ifpractieable.

Since the MWL is considered a SWMU. there are no specific regulations to determine the

minimum number of downgradient wells. only guidance which recommends an adequate numberof hydraulically downgradient monitoring wells in the uppermost aquifer. i i i contrast, RCRA

regulations require a minimum of three do\mgradient wells..

BoraoJe Wd/ VullO!

The EPA reviewed the DVDs of he borehole videos provided by SNL for monitoring wells8WI, MWI, MW2; MW3, MWS,

andMW6. The MWI

video indicared themost

corrosionof

its stainless steel screen. 1be MW3 video showed much less corrosion. with MW2 and aWl

displaying minimal cOrTosion. Since stainleSs steel contains nickel,. chromium., and iron., well

cOlTOsion may mask groundwater contamination by these metals. However, since the MWLReRA Facility Investigation (RFI) did not identify constituents in the landfill which would cause

significant chromium or nickel contamination, we believe the elevated groundwater levels of

these contaminants are probably caused by weU screen corrosion.

In addition, several of the wells had. broWlKOlored, encrustation-like material 011 the wellscreens. The MW3 video also had a fOOl long hoi. In the PVC casing 11140 feet, exposing the

annular grout. Periodic maintenance of wells should be used to clear sereen and/or sandpackobstructions.

Individual WeD Comments

BWl

CANM: Needs replacement Mud rotary drilling caused new mineralogy which masks

contaminants. Improper purging and sampling methods. Jncorrect location. Low water level.

NMED: Repiacemcnl: scheduled for early 2008.

EPA: Needs replacement.

The background well u located approximately 450 feet to the south southeast of the MWL Thismonitoring well needs to be replaced because water Ievel$ have dropped below the screened .interval, as indicared by the 2006 WIller level measurements and verified by the DVD log.Although recent measurements indicate the well may have become more cross-gradienl to theMWL than thought at the time of installation., this does not mean the data are unreliable; itshould not have been affected by the MWL due to its distance.

8



The n:pl. . mcnt well should be located cast (hydraulically upgradient) of the MW L and screened

with. PVC saecn ""ross the watcrtable in the AP aquifer. The NMED Iw already di=tedDOEISandia to r<pIace Ibis well aod & s scbcduled for installation hy early 2008.

MWI

CANM: A plume ofnickel contamination must be invtltigated and additional wens

installed within aod surrounding the MWL. Cross gradient. Improper water samplinsmethodology. Improper purgins aod sampling methods.

NMED: Needs replacement; scheduled for spring of2001. The nickel is not moving andit's probably due to well screen corrosion.

EPA: Continue furtherdiscussioD with NMED.

This well is located near the northern boundaryof the MWL. It should be n:pi1l<ed due to

corrosion of he stainless steel screen, low WIUr e v c ~ aod because the lower part of the screenedintcrvill is filled with sediment, which was seen in the video log.. Well wnples indicated the

presence ofchromium. nickel, and iron, the same constituents found in stainless steeL Since the

w<lI's looation oil the north side of the MWL Iw become m<»tly c:ross-gradient or up-gradlent tothe landfill, it's unlikely the well would detC<t cODtamination from the MWL . Although elevatedbackground lovcla of nickel have been do<umcnted in the 10<al...., the possibility exists forlongitudinal dispcrsioc northward from the MWL to this well.

Since corrooion problems could mask any chromium or nickel contamination from the landfil4

w< c:annot conelude wbcther the eh:voted nickel in tbe well is from the laodfill. Samplins of thegroundwater from a oew well or from: a borehole near MW 1 would provide conclusive results.

The NMED Iw ah<ady di=tcd DOEiSaodia to n:pi1l<c MW I with a well on the western side of

the MWL; it is S(:heduled for installation in earty 2008.

CANM: Mud rotary drilling caused new tnineJ1Uogy which masks confaminants. Improper

purging and sampliog methods. Low water level.

NMED:

EPA: Continue further discussion with NMEO.

The well is located on the northwestem: comer of the landfill and a.ppears to be cross-gradient SO

it is unlikely 10 observe releases &om the landfill with westerly groundwaa flow. The video logindicates very Jittle corrosion which seems to be confinned by the lack. ofchromium or nickel

exceedances in the samples. We recommend thai: this well be used to mea5UR groundwaterdevation unless corrosion problems occur later or the watct level drops.

In addition. we recommend further ~ t i o n on the north side of the landfill since we expec1

9



that the groundwater direction may tum more northward as the City of Albuquerque continues

pwnping. This well may be able to provide additional information unless it becomes

problematic.

MW3

CANM: Has never produced reliable data due to purging method an d mud rotary drilling.

Mud roWy drilling caused ne w mineralogy which masks contaminants. Improper purging and

sampling methods. Dedining water levels.

NMED: Replacement scheduled for spring of 2008.

EPA: Needs replacement.

This well is located on the western side of the MWL. It should be replaced due to corrosion ofthe stainless steel ~ e n and because.the water level is near the bottom of the screeoed interval.

as seen in the video log. Well samples indicated. the presence ofchromium, Dick.el, and iron. the

same constituents found in stainless steel. There is a foot long hole in the PVC casing at the 40

foot depth which appears to be the result of efforts to free jammed equipment.

The replacement well should be moved closer to the wlit boundary and h o ~ d have a PVC .

screen across the water table of the AF facies. The NMED has already directed DOE/Sandia to

replace this well and it is scheduled for installation in early 2008.

MW4

CANM: Needs to be immediately plugged and abandoned due to well screen across boththe AF and ARG_ Improper purging and sampling methods. Mistakes in drilling and

construction. Declining water level.

NMED: Does not need replacement. 1be well was refurbished a couple of years ago and

the old packer was removed and replaced. There is a significant vertical hydraulic gradient in

this area but no problem with ARG to AF c:omingling.


This well is driUed at an angle under the nonb side of he MWL. It has screened intervals in both

the shallow and deeper aquifers. Although the packer has been replaced. it is unc1eax if it is

providing an adequate sea] between the two well screens. Irnot. the two.aquifers may be mixing

in the well and providing a conduit between the deeper and shallow strata with the bulk of water

apparently provided by the more productive ARG aquifer. Lower nitrate concentrations may also

be an indication of mixing oftbc aquifers.. It is also unclear whether the screen was properly

placed at the water table of he AF facies based on the lithologic: log narrative which states that

the material recovered at the 398 to 410 foot interval was "'very moist."

In addition, since this well was placed within the landfill boundary, it docs not provide indication

10



,. .•

( ) f h o r i ~ t a J m o v ~ m e n t o f c o n ~ t i o n . At this poipt. we recommend plugging this well butadditional information is needed from NMED regarding the date the paCker was "'placed. Also,as discussed UDder MW2, we recommend fiuthcT investigation of the north side of the landfill SO

another well may be needed as • "'Placement.

MW5

CANM: Needs to be immediately plugged aDd abandoned due to well screen across txlththe AF and AKO and CODtaminalion with grout and bentonite <lay.

NMED: Does !tOI'need "'Plaoemcnt. The grout was suc:oessfully deaned and the wellsbould remain for water level monitoring. ,

EPA : Continue further disoussion with NMED.

Thi> well is lo<:ated about 140 'feet to the west of he MWL. Although the intent of ho well

appears to be monitoring Q f ~ allnvial fan strata. the well sc:r=n extends into the ARG. Sincethe ARG appears to be confined. the hydraulic gradient, ifany, appears to be upward to the' AFstrata. In adQition, i, is _lear if he grout was fully removed from the soreened interval or

formation. which could pievent representative sampling. This well m8y be useful to mr;asurc"Water level, however.

MW6

CANM: Installed in the AKG bu, too tar from MWL,

NMED: Keep this well for monitoring water level and flow

EPA: Keep this well for monitoring water level in the ARG.

This well is located about SOO feet to the west northwest of the landfill and monitors the ARO

facies. We recommend that it be maintained to measure water level and flow direction. The

water level in this well is approximately 15-20 feet above the top of the screen. indicating the

confined nat1.Jre"oftbis aquifer.

Summary aad Coaclusioos

Based on our review, we ha ...e determined that NMEO's overall actions and decisions for

administration of the authorized program ha ...e been technically sound and consistent with

applicable ReRA requirements. We have also found no C"Yidence to indicate that the MWLposes an imminent or substantial danger to citizens or groundwater supply.

As part ofour oversight responsibility, we maintain an open and ongoing dialogue with NMED.

routinely discussing program matters and raising any concerns we may have. It is ou r intention

to continue to discuss these issues with the State. Although it may appear there are differences of

11



,

opinion between EPA and NMED, we share the same goal: proteCt the environment of New

Mexico. In regard to the MWL, Ihe main priority is ensuring the effectiveness of the

groundwater monitoring network". Since NMEO is responsible for day to day administration ofthe delegated RCRA program. they are allowed leeway in specific details. as long as

environmental standards and requirements are m a i n t a i ~ d . In many instances, the -best way" is a

matter ofjudgmenl and experience, and we have confidence in their ability to run this program.

The decision to cover the MW L was made to reduce the potential for erosion. water infiltration.

and animal intrusion; it is not "F(nal Closure" with a permanent ReRA p . " Delaying the

cover may actually increase the possibility that contamination could reach the groundwater.

Long term monitoring was included to ensure prompt and apPropriate actions would be taken i fcontamination was found. The potential exists for future excavation ifdeeined necessary.

The original weBs were properly located based on knowledge ofgeology and gro!ltldwater at that

time. We believe they provided reliable, representative data and. effective detection monitoring-during their uscfullife. We have recommended ihat certain wells be plugged or I'q)laced due to

changes in groundwater.levels, weU Corrosion. aDd better tmdCrstanmng ofgroundwater flow.

We are confident the new wells and monitoring network will provide adequate/accurate data,

thus ensuring protection·of he groundwater. It would also have been preferable for the landfill

cover to have been fully in place by now.

Soil vapor sampling of the MWL is also planned. This was originally scheduled for early 2007

but has been delayed due to CANM inquiries and requests for information. We would like to seethis sampling move forward as soon as possible.

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Epa 6 Secret Report

Documents

Transcript of Epa 6 Secret Report