Homestake Mining Company Superfund Site
Activities Update
Cibola County, New Mexico
April 2011
This Fact Sheet will tell you about:
• Current Activities
• Background Information
• Questions/Answers
• Where to get more information
Current Activities
The U.S. Environmental Protection Agency (EPA)
has been conducting a risk assessment at the Homes-
take Mining Superfund Site beginning in late summer
2010. The purpose of this risk assessment is to ad-
dress concerns raised by the public living within the
adjacent residential subdivisions. The public has been
concerned that they are exposed to unacceptable le-
vels of radioactive contaminants through the inhala-
tion and ingestion routes of intake. Specifically, the
residents have been concerned that the contaminants
have been transported onto their properties through
the spray mist from the evaporation ponds associated
with the ground water remediation activities, through
emissions from the land application, and through their
use of contaminated ground water. The community
has also been concerned about the consumption of
produce in areas irrigated with contaminated ground
water and consumption of livestock meat exposed to
ground water in the area. The Homestake Mining
Company currently meets the Nuclear Regulatory
Commission (NRC) emission criteria; however, EPA
is conducting this risk assessment independently to
determine any risk to the residents.
Background Information
The Homestake Mining Company (HMC) Site is lo-
cated in Cibola County, just north of the village of
Milan and the town of Grants, New Mexico. HMC
operated a mill at the site from 1958 until 1990. The
mill was decommissioned and demolished between
1993 and 1995. Seepage from mill tailings wastes
(i.e., Large Tailings Pile and Small Tailings Pile) re-
sulted in the contamination of ground water with ra-
diological and non-radiological contamination,
including uranium, thorium-230, radium-226 and ra-
dium-228, selenium (Se), molybdenum (Mo), sulfate,
and total dissolved solids (TDS) among others.
Questions/Answers
The following questions were generated from the
meetings, from general community input, and from a
number of organizations involved with the mining
and milling situation in New Mexico.
Homestake questions
1. Will the community south of the Homestake Site
ever be able to use the ground water again?
It is unlikely that the ground water in the alluvial and
Chinle aquifers will ever meet the drinking water
standards of State of New Mexico or EPA without
adequate water filtration. All residences in the subdi-
visions near the Homestake Mining Company (HMC)
site have been provided a clean safe adequate water
supply through hook-up to public water service. This
action removed the immediate health and safety con-
cern to those homes. The ground water corrective ac-
tion will continue at HMC until the approved ground
water protection standards are achieved.
Due to the fact that background concentrations of
some contaminants are above drinking water stan-
dards, no amount of action at the HMC site will ad-
dress all the concerns associated with the use of
alluvial and Chinle aquifer ground water. It is impor-
tant to note that the approved ground water protection
standards will result in constituents in ground water
above Federal drinking water standards, but may be
-------
below New Mexico standards for other uses, such as
for watering or livestock use. HMC published a report
entitled, "Evaluation of Years 2000 Through 2009
Irrigation with Alluvial Ground Water," March 2010
(NRC ADAMS No. ML 100970370) which provides
estimates of the radiation dose to the public resulting
from irrigation activities, eating vegetation and beef
watered with alluvial water, and living on irrigated
property. The report states that".. .the radiological
dose to existing or future occupants of the land on and
near the irrigation areas is extremely small (less than
one percent) compared to the average dose that the
population receives from natural background and
medical exposures."
2. Why were the ground water protections standards
(GWPS) changed and raised to make it easier for
HMC to close the site in the future? What was the ba-
sis for the changes?
The GWPS were not revised to make it "easier" for
HMC to close the site in the future. The GWPSs for
the HMC site were revised in 2006 to reflect the
background concentration of contaminants in aquifers
that are affected by off-site derived contamination.
The revision of the GWPS for the HMC site acknowl-
edges differences in specific contaminant background
concentrations among the affected aquifers. These
differences were not reflected in the original GWPSs
for the site.
The GWPS change was based on an evaluation of ex-
isting data that was collected over 20 years to deter-
mine background concentrations of constituents
hydraulically upgradient of the site. Ten years of data
from a group of wells up gradient of the site provided
information about contaminant concentrations in the
alluvial aquifer up gradient of the site that were not
influenced by HMC activities. These levels were
higher than previously approved background levels
which were based on three samples collected from a
single monitoring well. HMC was able to demonstrate
background levels of contaminants in the upper, mid-
dle and lower Chinle aquifers by interaction of these
aquifers (sub cropping) with the alluvial aquifer that
were not influenced by the HMC site.
NRC, EPA and New Mexico Environment Depart-
ment (NMED) took more than two years reviewing
and examining HMC's analysis. In the end, each reg-
ulatory agency concluded that HMC provided ade-
quate technical bases for the revised background
values.
3. Is it safe to live in my neighborhood adjacent to
the HMC site? Are radon levels safe inside or outside
my home? Is it safe to use ground water for vegetable
gardens or in evaporative coolers?
There is no universally accepted radiation exposure
level which is considered "Safe." The EPA is the
government agency responsible for establishing stan-
dards limiting the radiation dose to the general popu-
lation from nuclear power plants and also from other
parts of the nuclear fuel cycle. Currently, the EPA
limit for the general population is set at a 25-mrem
whole-body dose from nuclear facilities. In its regula-
tions, NRC requires HMC to meet a number of dose
standards which NRC has determined to be safe.
First, 10 CFR 20.1301(a)(l) requires HMC to meet an
operational public radiation dose standard of 100
mrem/yr Total Effective Dose Equivalent (TEDE).
Second, HMC must comply with the air emissions
constraint of 10 mrem/yr established in 10 CFR
20.1101(d). Finally, HMC must demonstrate com-
pliance with the annual whole body dose limit of 25
mrem/yr established by EPA (40 CFR 191.10) and
cited by NRC in 10 CFR 20.1301(e). This annual
whole body dose limit excludes dose from radon and
its daughters. HMC is currently in compliance with
all of these standards.
Even though HMC is currently in compliance with all
of NRC standards, EPA is conducting a risk assess-
ment to assure any risk to the public is within the
CERCLA acceptable risk range during the on-going
clean-up.
The "average person" living in the United States is
exposed to approximately 620 mrem of radiation
every year. Fifty percent of this exposure comes from
natural sources such as radon in air and cosmic rays,
and 50% comes from human activities. Medical diag-
nosis and therapy account for more than 90% of the
man-made dose. Some activities, occupations, and
areas expose a person to a greater-than-average radia-
tion dose. Due to the presence of high quantities of
naturally occurring uranium in the Grants Mining
District, persons living in this region are generally
exposed to a greater-than-average radiation dose from
natural sources.
Radon levels inside and outside residents' houses near
the HMC site are due to the presence of naturally oc-
curring radon, and radon emanating from the HMC
site. EPA evaluated the impact of the HMC site on the
adjacent subdivisions in the 1989 Record of Decision
-------
(ROD) and determined that no action was required to
address indoor radon gas EPA determined that al-
though the radon concentrations were elevated, the
principal cause was not related to the site, but to local
sources of radon. Since the 1989 ROD, EPA has is-
sued two Five-Year Reviews that have concluded that
the no action remedy remains protective.
Residents near the HMC continue to have concerns
regarding exposure to radiation originating from the
HMC site. In September 2009, EPA initiated a risk
assessment to characterize and quantify the current
and potential human health risks for residents living
near the HMC site during the on-going remediation
phase. In September 2010, EPA began its radon sam-
pling program designed to determine the radon levels
inside and outside homes in the neighborhoods sur-
rounding the HMC site. The resultant risk assessment
will provide an updated evaluation of the risk posed
to residents.
4. Why is so much clean water being removed from
the deeper aquifer and injected into the shallow con-
taminated zone? Isn 't this just diluting the problem?
Clean ground water from deeper aquifers is being in-
jected into the alluvial aquifer down-gradient of the
contaminant plumes rather than into contaminated
zones or plumes. The injected ground water increases
the ground water elevation around the point of injec-
tion which results in the reversal of the ground water
flow direction. Homestake has installed numerous
points of injection to establish a hydraulic barrier
from the mounding ground water. The injected
ground water is not being used for remediation of the
alluvial aquifer nor is it used for dilution of the con-
taminant plume. Ground water injection is simply a
method used to reverse the ground water flow direc-
tion, which in turn, reverses the contaminant plumes
within the alluvial aquifer. Extraction wells are placed
within the contaminant plumes to capture contami-
nated ground water and to enhance ground water re-
versal from the points of injection.
5. Shouldn 't HMC be required to install monitoring
wells in the alluvium, Chinle and San Andres aquifers
down-gradient of the contaminant plumes to monitor
for contamination ahead of the plumes? In addition,
wouldn 't monitoring wells ahead of the plume estab-
lish background water conditions for the area?
The agencies believe that HMC has an adequate
number of monitoring wells to characterize the con-
tamination plumes and document reclamation activi-
ties. Although a region-wide approach to ground wa-
ter restoration is needed, NRC does not have the
authority to regulate ground water reclamation activi-
ties for the entire Ambrosia Lake-Milan area or re-
quire HMC to establish a regional ground water
monitoring program. Data from monitoring wells
down-gradient of the HMC contaminant plume may
or may not be representative of "natural" background
for the area. "Natural" background water quality de-
pends on several factors including local geology and
hydrology. How well data from monitoring wells
ahead of the HMC contaminant plume represent "nat-
ural" background also depends on the presence or ab-
sence of non-HMC contamination from upgradient.
Regardless, HMC's ground water clean-up standards
are based on the concentrations of constituents of
concern (COCs) in the ground water up-gradient of
the HMC site. The EPA is facilitating a technical
ground water workgroup comprised of state and fed-
eral partners, as part of the Five-Year Plan, to eva-
luate the regional ground water.
6. Remediation activities at HMC are not adequate
to address ground water contamination near Milan,
NM. Shouldn't remedial actions be expanded to in-
clude contamination coming from the Ambrosia Lake
andBluewater Mill areas?
The agencies agree that ground water contamination
issues should be addressed in a region-wide approach.
However, HMC's responsibility does not extend
beyond HMC's licensed activities. Federal and State
agencies have prepared a Five-Year Plan to assess the
health and environmental impacts from Uranium min-
ing and milling in the Grants Mining District, New
Mexico. The purpose of the plan is to compile all ac-
tivities contributing to the identification and clean-up
of legacy uranium milling and mining activities in the
Grants Mining District. The EPA is facilitating a
technical ground water workgroup comprised of state
and federal partners, as part of the five-year plan, to
evaluate the regional ground water.
Background Water Quality
7. Why don't the COC background values estab-
lished for the HMC site meet federal water quality
standards?
In accordance with NRC regulation 10 CFR 40, Ap-
pendix A, Criterion 5, ground water reclamation stan-
dards are established such that at the point of
-------
compliance, the concentration of a hazardous consti-
tuent must not exceed (a) The NRC approved back-
ground concentration of that constituent in the ground
water; (b) the constituents maximum value for ground
water protection if the constituent is listed in Table
5C; or an Alternate Concentration Limit (ACL) estab-
lished by the NRC. In order to establish the ground
water clean-up standards for the HMC site, it was ne-
cessary to determine the background values for each
of the site hazardous constituents. NRC does not re-
quire licensees to clean up water not attributable to
site operations. Since the HMC is impacted by up-
gradient contaminants, it was not reasonable to estab-
lish "natural" COC background values as the site
ground water clean-up standards. Instead, the NRC
established background values for the site COCs
based on the concentrations in each of the aquifers
immediately up-gradient of the HMC site. These
COC background values were used to establish the
ground water protection standards for the various
aquifers at the HMC site. In the NRC license issued to
HMC, license condition 35 B formalizes the ground
water protection standards HMC will be required to
achieve. These standards were reviewed and approved
by NRC, with concurrence from EPA and NMED.
8. What are NRC, EPA and NMED doing to address
contamination impacting the HMC site from other
sites in the region? We have contaminants moving
through our properties from upstream sources, Blu-
ewater/Arco, past mining and milling sites, etc.
The Department of Energy (DOE) is maintaining the
Bluewater site as outlined in the long term surveil-
lance plan (LTSP). Alternate concentration limits
(ACLs) were approved for the Bluewater site in 1996,
and levels of constituents at the site are currently
within those approved limits. DOE currently has five
points of compliance (POC) wells and two point of
exposure wells (POE) at the site. The three alluvial
POC wells are sampled annually and two bedrock
POC wells every three years to confirm that alternate
concentration limits are within approved limits. The
wells are sampled for Mo, Se, uranium (U) and po-
ly chlorinated biphenyls (PCBs), with exception of the
bedrock wells that are only sampled for Se and U. Al-
though DOE is in compliance with its LTSP, uranium
concentrations in alluvium Point of Compliance Well
T(M) have been trending upward. The trend suggests
that the ACL of 0.44 mg/1 may be exceeded in the
near future.
In coordination with the Grants Mining District Five-
Year Plan, DOE is conducting ground water investi-
gations at the Ambrosia Lake and Bluewater Mill
sites to investigate the increasing uranium concentra-
tions in the alluvial POC well.
The Five Year Plan was developed to address this
very issue. As part of the Five-Year Plan, EPA and
NMED will complete pre-CERCLIS screening as-
sessments of identified sites up gradient of the HMC
site and within the San Mateo watershed. The Mining
and Minerals Division of the New Mexico Energy,
Minerals and Natural Resources Department is also
assessing former uranium mine sites in the Grants
Mining District. These efforts may lead to more tho-
rough assessments of sites identified as potential
source areas contributing to ground water contamina-
tion.
Health Impacts/ Nuisance
9. Our citizens have been drinking contaminated wa-
ter for years from this site; what are the health im-
pacts?
The health impacts to residents living near the Ho-
mestake site from drinking contaminated water in the
past have not been evaluated and the agencies have no
plans to conduct such a study. Prior to September
1975, when EPA began the ground water sampling,
the agencies were unaware of contamination in the
alluvial ground water in the area. As a result of this
study in 1983, Homestake entered in to an agreement
with EPA to provide a safe water supply through city
water hookup which essentially eliminated the poten-
tial health risk from continually consuming contami-
nated water from the site after hookups were
completed in April 1985. Although EPA is currently
conducting a human health risk assessment, the risk
assessment does not address the health outcomes due
to past exposures. The primary objective of the EPA
risk assessment is to determine whether site contami-
nants (constituents of concern) pose a current or po-
tential future risk to human health in the absence of
any remedial action in accordance with the EPA's
Risk Assessment Guidance for Superfund (RAGS).
Research institutes and universities have conducted
epidemiological retrospective studies to evaluate the
health impacts from past exposures. Such a study was
recently published in a paper titled, "Cancer Inci-
dence and Mortality in Populations Living Near Ura-
nium Milling and Mining Operations in Grants, New
-------
Mexico, 1950-2004," Boice, J.D., Jr., Mumma, M. T.
and Blot, W. 1, Radiation Research 174, 624-636
(2010). However, the study had many limitations and
did not provide clear evidence that the operation of
uranium mills and mines adversely affected cancer
incidence or mortality of county residents.
10. The evaporation ponds often have a smell. Is this
affecting my health?
No, the smell has no affect on human health. The
smell is caused by the presence of algae in the ponds.
HMC has been working to control odors from the
evaporation ponds by adding a combination of copper
sulfate and citric acid to the ponds. The citric acid
keeps the copper sulfate bio-available for algae and
therefore keeps algae bloom down (kills algal growth)
when the water temperature rises in the ponds during
the summer months. This chemical combination acts
as an algaecide. The proposed evaporation pond #3 is
located to the north of the site, and additional smell
should be minimized.
Water Withdrawal
11. HMC is pumping a large amount of water from
their wells; is it impacting off-site wells and surface
water?
The extracted ground water, which is a necessity for
ground water remediation, is only a fraction of the
consumptive ground water use in the immediate area
surrounding the Homestake site. Wells used for irri-
gation, industrial and domestic purposes, as well as
natural factors such as drought, all contribute to
ground water impacts. The Office of the State Engi-
neer regulates and issues permits for ground water
extraction wells. The State Engineer is responsible for
assessing impacts associated with the proposed water
use prior to issuing a permit. Applications for water
consumption permits are publicly noticed to allow for
public concerns related to the application. A large
portion of the extracted ground water is injected back
into the subsurface to reduce the impact caused by
ground water extraction.
Property Values
12. Why do we have to pay for public water when it
was free before?
The agencies mission is to protect public health, safe-
ty and the environment. Cooperating agencies have
worked to insure that public water was provided to
residences to protect public health and safety. The
water lines constructed in the subdivisions provide
safe, potable water and it is standard environmental
practice where public lines are located nearby to hook
homes up to public water systems. At sites where
ground water has been contaminated above standards,
the remediation goal is restore ground water either to
meet federal and state standards or background con-
centrations if they are higher than the applicable stan-
dard. Remediation standards (e.g. drinking water
standards) are intended to protect specific uses. In the
case of the Homestake site, contamination from nu-
merous off site legacy sites has trespassed onto the
site. The cost of water from a public water system
covers the delivery of water that is monitored to en-
sure safe potable water
Timeliness of Cleanup
13. HMC is not doing enough; why haven't they
cleaned up the site in the last 25 years?
There was an extremely large volume of tailings and
slimes placed in the unlined tailings impoundment
that have leaked into underlying aquifers. Evaporation
pond #3 will help to speed up ground water cleanup at
the site. However, as noted previously, extraction and
injection technology is a slow process which can take
several decades to clean up ground water, but it can
provide containment while being implemented.
Other Alternatives
14. Why can't the tailings pile be moved? Why won't
NRC and EPA work to move the tailings pile to an
offsite location like the Moab Site in Moab, UT?
The primary distinction between HMC - Grants and
Atlas/Moab is that the Floyd D. Spence Defense Au-
thorization Act conferred UMTRCA Title I status on
the Moab site and gave DOE authority to clean-up the
site. At the time the Act was passed, the licensee had
gone into bankruptcy and the trustee for the site had
insufficient funds to complete reclamation. As a result
of the Act, funding to remove the tailings from Moab
to another site is being provided by the Federal gov-
ernment. HMC - Grants is a Title II site under
UMTRCA and an NRC licensed site. HMC is respon-
sible for the clean-up and is operating under an NRC
approved reclamation plan where partial surface rec-
lamation has occurred and final surface stabilization
will occur after ground water remediation is com-
plete. Ground water remediation is occurring. The
reclamation plan and remediation is designed to be
-------
protective of public health and safety. The environ-
mental clean-up is ongoing. The licensee has not pro-
posed moving the tailings and NRC has no basis to
require it. There is currently no consideration of mov-
ing the tailings impoundment.
Where to get more information
Sai Appaji
Remedial Project Manager
U.S. EPA Region 6 (6SF-RL)
Tel: 214.665.3126
Fax: 214.665.6660
appaj i. sairam@epa.gov
Stephen Harper
Community Involvement Coordinator/SEE
U.S. EPA Region 6 (6SF-VO)
Tel: 214.665.2727 or 1.800.533.3508 (toll free)
Fax: 214.665.6660
harper.stephen@epa.gov
David L. Mayerson
Ground Water Quality Bureau
Superfund Oversight Section
New Mexico Environment Department
Tel: 505.476.3777
Fax: 505.827.2965
david.mayerson@state.nm.us
Site Repositories
New Mexico State University at Grants
Campus Library
15 00 Third Street
Grants, NM 87020
505.287.6639
New Mexico Environment Department
Harold Runnels Building
1190 St. Francis Drive
Santa Fe, NM 87505
For press inquiries, please call, EPA Press Office, at
214.665.2200.
You can find more information about the Region 6
Superfund program on EPA's Region 6 website:
http://www.epa.gov/region6/superfund
Para recibir una traduccion en espafiol de esta hoja de
datos, comunicarse con la Agencia de Protection del
Medio Ambiente de los EEUU (la EPA) al numero de
telefono 1.800.533.3508 (llamada gratis).
On the web:
http://www.epa.gov/region6/6sf/6sf-nm.htm
------- |