Unittd Stales      Eattem ErmiroomeolaJ    B»A 520/1-83-007
           Environment* Protection   Radiation Facility      June 1903
           Agency        P O Bex 3009
           Office of RatfiBtion Program*  Montgomery. AL 36193

           Radiation                       ~
           Potential Health and
           Environmental Hazards of
           Uranium Mine Wastes

            Executive Summary
  Report To The Congress
          Of The United States
f
i
          Volume 1 of 3 Volumes

-------
                                 EPA 520/1-6-83-007
     POTENTIAL HEALTH AND ENVIRONMENTAL

       HAZARDS OF URANIUM MINE WASTES



              Executive Summary
A Report to the Congress of the United States
      in  Response to Public Lav/ 95-604
                June 10, 1983
     U.S.  Environmental  Protection Agency
        Office of Radiation Programs
           Washington, D.C.  20460

-------
                              CONTENTS


SECTION

   I      INTRODUCTION                                            1
               Purpose of the Report                              1
               Contents of the Report                             1
               Scope of the Report                                3
               Brief Description of Uranium Mining  Operations      6

   II     ACTIVE MINES                                            8
               Number of Mines                                    8
               Health Impact of Air Emissions                      8
               Health Impact of Water Emissions                   10
               Health Impact of Solid Wastes                     12

   III    INACTIVE MINES                                         14
               Number of Mines                                   14
               Health Impact of Air Emissions                     14
               Health Impact of Water Emissions                   16
               Health Impact of Solid Wastes                     16

   IV     CONCLUSIONS AND RECOMMENDATIONS                         19
               Conclusions                                       19
               Recommendations                                   22

   V      OTHER FINDINGS                                         23

-------
                              SECTION  I

                            INTRODUCTION

PURPOSE OF THE REPORT

    Uranium  mining  operations   release  some  radioactive  materials
into  both air  and  water and  generate  large  quantities  of  solid
v/astes containing  low levels  of  radioactive materials.   Solid wastes
produced  by  past  mining  operations  remain  on  the  surface  at  many
inactive  mining   sites,   and  represent  a  potential   health   and
environmental hazard similar in concept to  uranium mill  tailings.
Contamination  of   surface   and   subsurface   water  supplies   also
represents  a  potential   problem.    To  evaluate   these  potential
problems,  the  Congress,   in  Section 114(c)  of  the  Uranium  Mill
Tailings  Radiation  Control  Act  of  1978  (UMTRCA),  instructed  the
Administrator  of  the  Environmental  Protection  Agency  (EPA)   to
prepare  a  report  "which  identifies  the   location  and  potential
health,  safety,  and  environmental  hazards  of  uranium   mine  wastes
together  with  recommendations,   if  any,  for a  program  to  eliminate
these hazards."
    This  report   analyzes the   potential  health  and  environmental
impacts  of  both  active  and  inactive  uranium  mines,  lists   the
locations of  these mines, identifies additional  information  needs,
and recommends needed actions.

CONTENTS OF THE  REPORT

    This  Executive  Summary   contains a  brief  description  of   the
material  presented  in   the  main  text,  including   the  principal
findings,  conclusions,   and   recommendations.    The   full   report
consists  of  this  Executive  Summary,  a  main  text,  and  appendices.
The  full  report  has  been reviewed by  the  uranium mining  industry,
States  and  the  Nuclear  Regulatory Commission.   Comments  have  been
incorporated where possible.

-------
    The Agency could not  assess  the  environmental  impacts  of uranium
mining on a  site  specific basis because of  a lack of  adequate  time
and data.  Instead, we  have  done a generic assessment  to  develop  an
overview of  the  regional  impacts  of  the industry.  We  believe  this
assessment to  be  fully responsive to the  concerns which  initiated
this request to the  Agency,  and to adequately evaluate  the regional
environmental impacts of  the uranium mining  industry  in  the  United
States.
    This   assessment   is   based    on   mathematical   models    of
representative  (average)  facilities, classed by  type  and  size  of
operation.    Such   models  do  not  necessarily  correspond   with   the
operation of  any  specific individual  mine,   and  the  assessments  of
environmental impacts  should not  be associated  with  releases  from
any  particular  mine.   Such  an  analysis  can  present  a   composite
picture,  and  can  be useful  in  determining  if  there   is a  need  for
actions on a national scale.
    In making this assessment,  we have generally  used  realistic  but
conservative  parameters  which  tend  to  overestimate  the   potential
environmental impacts.   This was done deliberately, with  the  intent
of putting an upper bound on the possible impacts.  As  a result  some
mining  operations may  cause  substantially   lower impacts  than  is
indicated in this report.  Therefore, this  study  should not be  used
to assess the potential environmental impacts of  any  specific mine,
and  it should  be  recognized that  there  is  a wide diversity  within
the industry.  Use of the results  of  this study  should  be  limited  to
the purpose for which they were developed.

-------
    Main text

    The main text consists  of  seven  chapters covering the  following
subject matter:

           --a general  description of uranium mining
           —an inventory of both active  and  inactive  uranium mines
           --sources and amounts  of pollutants released to the
                 environment
           --amounts of solid waste generated
           --pathways of human  exposure to  pollutants
           --health  risks and environmental impacts
           --recommendations and  conclusions

     Appendices

     The appendices  cover the following subjects:

           --a detailed listing of the active and  inactive
                 uranium mines  in the United  States and their
                 locations
           --observations of existing conditions at
                 selected inactive mines
           --a description of the methodology used in  the health
                 risk and environmental impact assessments

SCOPE OF THE REPORT

          This report  addresses  potential  health impacts  caused by
air  and water emissions and  solid  wastes  at active  and  inactive
underground  and  surface  mines.   We   emphasize  radiological impacts
because we  believe  these to represent  the  most  significant health
hazards  although  nonradiological  aspects  of  ground  water  and  air
contamination  were   also  studied.    Impacts  from   other  mining
activities,   such  as   exploration,  site   preparation,  and   in   situ
leaching,   were   evaluated  in    proportion   to  their    potential
significance and  the amount of  available  information about them.

-------
     Pathways of Exposure

     Underground  and   surface   mining   release  radioactivity   and
chemicals  into  air  and water  and generate  solid wastes  that  may
spread  through  wind and  water  erosion  and  release  radon-222  into
air.  We have examined  the extent  to  which people may be exposed  to
these released materials or  residual  solid wastes and thereby  incur
an increased chance of cancer or other health  effects  from:

          —breathing air containing  radon daughters,
          —drinking water containing  uranium  and its  daughters,
          --eating food contaminated  by  either air or  water,  and
          —living in homes on land covered by mine  wastes.

Estimates  of the  health  risks  from  each   of  these  pathways   are
presented in this report.

     Method of Analysis

     Our    preliminary    evaluations    indicated   little    actual
environmental data is  available  to evaluate the impacts of  releases
from  uranium mines.   Therefore, we  developed models  of  active  and
inactive mines using the  available data and evaluated these  impacts
on  a  broad  generic  basis.    To the   extent  possible,   operating
parameters and pollutant release rates characteristic of the  various
classes of  mines  were  used in  our models.   Finally we extrapolated
the health  risks  from  the  model  mines to  obtain an estimate of  the
total  health effects from  all  active  and inactive mines on  regional
populations within 50 miles from each mine.  We  estimate the  risk  to
the total  U.S.  population is  no  greater  than  a  factor  of  3  or  4
higher than our estimates for regional  populations.
     The  availability  of  information  to assess   the   health   and
environmental impact from  uranium mines  varied  greatly  depending

-------
upon the type of release and pathway of exposure.   In  some  cases,  we
had to assume the most appropriate values  to use in the analyses.
For  some  release-pathway  combinations,  we  were  able  to  make   a
quantitative    risk    assessment.     For    other    release-pathway
combinations, the information was  so  limited that we  could  identify
only the potential for impact.
     We  have expressed  the  health  and  environmental impacts  in  this
report in a number of different  ways:
          --Estimates of the risk of cancer  to  individuals
               and to population groups
          --Estimates of the risk of genetic effects to
                 the descendants of exposed  individuals and
                 population groups
          --Estimates of radioactiviy  and  chemical  concentrations in
                 the environment and a  comparison of these
                 concentrations  with air or  water standards  or with
                 existing background levels
          --Estimates of land areas disturbed,  amounts  of
                 solid wastes generated, quantities of  water
                 discharged,  and quantities  of  contaminants
                 released to air and water
          --Qualitative observations of a  potential  health
                 impact
It must  be  recognized  that the  primary effect of  radiation  exposure
is cancer although genetic  effects are  also  evaluated.

     Uncertainty of Health  Risk  Estimate

     To  assess the increased chance of cancer  and  of genetic  effects
occurring  after  exposure to  radiation,  Federal  agencies  base  risk
estimates  on studies  of  persons  exposed at  high  doses  and assume
that the effects  at  lower  doses will  be proportionately less.   Such
assessments  are  based  on  a statistical'risk  to  all   persons  in   a
large  population  exposed  to a  known  radiation dose.   Because  of
uncertainties in the  health  risk analyses presented in this  report,
these estimates should be used carefully.

-------
BRIEF DESCRIPTION OF URANIUM MINING OPERATIONS

     The  two  major  mining methods  used  in  the  United States  are
underground and surface  (open pit) mining.  During  1978,  underground
mines produced 5.5 million metric  tons  of  ore containing 8300 metric
tons  of   uranium   oxide   (U308)  while   surface  mines   produced
7.5 million  metric   tons   of  ore   containing   8700   metric   tons
of U-jOg.    In  situ    leaching,   heap   leaching,   and   mine   water
extraction methods  accounted  for the remaining  1300 metric  tons  of
UgOg production.

     Underground Mining

     Underground mining  uses  shafts  and  tunnels to gain  access  to
the  ore.   A  mine  may  extend  underground for  a  mile  or more  at
several  depths.   The  ore  is moved  to the   surface  and stored  for
transport  to  a  uranium mill.   Waste  rock   and  sub-ore*  generated
during  mining  are  also  stored  at  the surface as  a  waste  pile.   At
most  underground  mines,  these  wastes  remain  on the  surface  when
mining ceases.
     Large  capacity  ventilation   systems  are  used  at  underground
mines to   keep  the   radon-222   decay  product   concentrations  in  the
working areas  below  occupational  exposure limits.   Air is  usually
forced  down through  the  main  shaft along the tunnels to  the  working
areas   and  then  exhausted  through  ventilation   shafts.    Large
underground mines  may have as  many  as  a  dozen  ventilation  shafts.
However, while ventilation removes radon-222  decay products from the
working areas, it discharges radon-222 to the  atmosphere.
*Sub-ore contains  uranium at  a  concentration uneconomical  to  mill.
This  concentration  varies  with  the   "cutoff  level"  of  the  mill
receiving  the  ore.  The  cutoff  level   is  usually determined  by  the
cost of milling vs. the value of the recovered uranium.

-------
     Surface Mining

     Surface mining is done by excavating one  or  more  pits.   The top
soil and  overburden  above the ore  are removed and  stockpiled.   The
uranium ore is then removed and  stockpiled  for shipment  to a uranium
mill.  Sub-ore is  also removed from the pit during  these operations
and stockpiled for possible future use.
     The  present  practice at  most   surface  uranium  mines  is  to
backfill the mined out pits with  overburden as part  of a reclamation
program.  However, even  though backfilling  is performed,  some  waste
remains on the surface  after  mining is completed, and the  final  pit
may  not   be   backfilled.    Most  older  inactive  mines   were   not
backfilled and little or no reclamation was  done.

     Mine Dewatering

     Since  most  uranium  ore   deposits are  below the  water  table,
groundwater  must  be   controlled to   prevent  mines  from  flooding.
Underground mines  and  most surface  mines are  dewatered  to  allow for
excavation  or  shaft  sinking and  ore  removal.   Both underground  and
surface  mines discharge  this  water  to   natural  surface  drainage
systems.  The discharged water,  if  necessary,  is  treated with  barium
chloride and allowed to  settle to reduce  radium and  suspended  solids
before it  is  released.   In addition to local  effects, the long-term
impacts  on   regional   water   availability   and  quality   are   also
important considerations.

     Exploratory  and Development Drilling

     The   uranium   industry   has   drilled  approximately   1,300,000
exploratory  and  development  drill  holes through  1977.    It  appears
from mine  site  surveys  and  aerial  photography that very  few  drill
sites  have  been  reclaimed.   Some States do  require  backfilling  of
drill holes.

-------
                                  8

     The  average  drilling  depth  has  increased  with  time and  will
probably continue to do so  in  the future.   Deeper  drilling will  tend
to  increase  the possibility  that aquifers with  good  quality  water
may  be  degraded  by  being  connected,  via  the  drill  holes,  with
aquifers of poorer quality water.

                             SECTION II

                            ACTIVE MINES

NUMBER OF MINES

     In 1978 there were about  340  active uranium mines  in  the United
States.   A  list  of  these mines is  presented  in  Appendix  E  and
includes the type of  mine,  location,  and owner.   Table  1  summarizes
the locations,  numbers,  and types  of active mines:


                               Table  1
          Location of  Active Mines in  United States in 1978
                                                             Other
                                                                4
                                                                3
                                                                1
                                                                3
                                                                2
                                                                0
Total            60               256              11            13


HEALTH IMPACT OF AIR EMISSIONS-ACTIVE MINES

     Radiological  Impacts

     Exposure to radionuclide  emissions into  air from  active  uranium
mines increases the chance  of  cancer.   These  risks of cancer  are the
State
Colorado
New Mexico
Texas
Utah
Wyomi ng
Other
Surface
5
4
16
13
19
3
Underground
106
35
0
108
6
1
In situ
0
0
8
0
3
0

-------
                                  9

primary  public  health   impact   from  air  emissions  due  to  active
uranium mines.   Individuals  who might  be  living near  uranium  mines
are exposed to  higher  radiation risks than those farther  away.   Our
estimates  of  potential  impacts  are  based  on  model   mines  in  the
absence  of   adequate   field  data.    For  our  model   of   a   large
underground mine we  estimate that individuals living for  a  lifetime
1 mile  from the mine would  have an  increased  chance  of  fatal  lung
cancer  of  2  in  a  thousand  resulting  primarily  from  breathing
radon-222 decay products.  The  increased risk caused by  the mine to
an  individual  living 25 miles  away  is  several  hundred  times  lower.
Risks from other types of uranium mines are somewhat lower.
     We estimated  the health  impact  from all  active   uranium  mines
operating in  1978  by multiplying the risks  from the model  mines by
the  number  of active mines  of  each  type.   This procedure  provides
only a  very rough  estimate  of  the total  population risks  from  all
mines and is  accurate  only to  the  extent the model mine  represents
an average for all operations.   Based on  this  rough extrapolation of
the  total  risks from all  mines, we  estimate  that  the  radionuclide
emissions into  air from all   active  uranium  mines  operating in  1978
would cause  less  than  one fatal cancer  in  the  regional  population
living around these sites.
     The  risk  of   genetic  defects   in  future  generations  due  to
airborne  radiation  exposure   from   uranium  mines is   very   small
compared  to  the   natural  occurrence of  hereditary  disease.    The
largest potential  increase in genetic defects would occur  near  large
surface mines.  Exposure of  the population near  a large surface  mine
for  one year  is  estimated  to  result   in  a  very   small  chance  of
additional  genetic effects  to  their descendants  (less than  0.0001
such effects in the population).

-------
                                 10

     Nonradiologi'cal Impacts

     We   estimated   the   air   concentrations   of   nonradioactive
pollutants produced by our model mines at an  assumed  location  of  the
nearest individual—1 mile from  center  of mine  site—and  determined
the  following  emissions  presented  minimal   potential  risk  to  the
population:

          --airborne stable trace metals
          —airborne combustion products  from heavy equipment
               operation
          --nonradioactive gas emissions  at  in situ leach  mines

However, the estimated concentrations of particulates in the form  of
dust in  ambient  air near  large  surface  mines exceeded the  national
ambient air  quality standard.  Most dust near active surface  mines
is caused by vehicle traffic.

HEALTH IMPACT OF HATER EMISSIONS-ACTIVE MINES

     Radiological Impacts

     The  health  risks due  to radionuclide  emissions  to  water  from
active  uranium  mines are  lower  than  those  caused by  radionuclide
emissions  to  air.  Although  we  were able  to estimate cancer  risks
caused   by   radionuclides   in   discharged   water  from  our   model
underground and  surface mines, we  could  not do  so  for  in  situ leach
mines  because of insufficient data.  However,  radionuclide  releases
in water appear to  be low  from in  situ mines.   As with  our estimates
of air emission  impacts, models  utilizing some actual  data  were used
to develop this information.

-------
                                 11

     For our model of an average  underground mine,  we  estimated  that
individuals  living  for  a  lifetime 1  mile  from an underground  mine
would have an  increased  chance of cancer of about  one in a  hundred
thousand due to  releases  to surface water.   Ue estimated  that about
one additional cancer in  several  hundred years might  occur from  the
normal controlled releases from these mines.
     However, mine water  discharged to  nearby  streams can recharge
shallow  aquifers,  many  of which  are  presently  used  for drinking
water or may be in the future.  We do not have  enough  information  at
this  time  to evaluate the potential  health risks  from using these
aquifers, but  using  these aquifers for  drinking  water could  result
in increased radiation exposure.
     Where such a problem  may exist,  the state radiological  program
should  investigate  existing  records to determine  the contaminant
levels   in   these  aquifers   due   to  mining,   and   evaluate   the
significance of the health risks  from using these  shallow aquifers.
If a  state determines  that sufficient data do  not exist to  perform
an evaluation, additional  sampling and  analyses should be performed
by the state to acquire  the necessary  data.

     Nonradiological  Impacts

     We estimated the concentrations of  nonradioactive pollutants  in
the streams  used  by the general  population of the region from  our
mine  models.   These concentrations  were from  dewatering  the model
mines and  were calculated after  the discharge was diluted  by   the
receiving  stream.   Under  these  conditions,  none  of  the  pollutant
concentrations  alone  or  in  combination  exceeded the   EPA Water
Quality Criteria concentrations for  use  in  irrigation and livestock
water.   However,  the recharge  of shallow  aquifers and the  use  of
these  aquifers  for  drinking  water present   a   potential   problem
similar to  that  discussed for radionuclide  emissions.  Thus  States
may want to  evaluate  pollution  concentrations to ensure drinking
water standards are met.

-------
                                 12

HEALTH IMPACT OF SOLID HASTES-ACTIVE  MINES

     Radiological Impacts

     Uranium mining  operations generate  large  quantities  of  solid
wastes containing  low levels of  radioactive  materials.   An  average
surface mine  generates about 6  million metric  tons  of  solid  waste
per  year,   while   an  underground  mine   generates  considerably
less—about 20 thousand metric tons  per year.   These wastes  consist
of  sub-ore,  waste  rock,  and  overburden.   At  surface   mines  the
sub-ore  comprises   only  a  few   percent  of   the  waste  while   at
underground mines, because much  less waste is produced,  the  sub-ore
may comprise up to 90 percent of  the waste.
     Through  wind,  water erosion,  and  release  of  radon-222,  these
wastes can  potentially contribute  to  air and water pollution.   These
wastes pose this  hazard  because they  contain elevated  concentrations
of  radium-226.    Sub-ore  (depending   upon  the  cutoff   grade  for
milling)  may  contain  up  to  50  picocuries  per  gram  (pCi/g)   of
radium-226, and,  even though the  overburden  and waste rock  contain
lower   concentrations  of   radium-226   than   the   sub-ore,   large
quantities  of  these  wastes  can contain concentrations of  radium-226
in  excess  of 5  pCi/g.*   EPA has  proposed  that uranium mine  wastes
containing  radium-226 in quantities  greater than 5  pCi/g be  listed
as  "hazardous  wastes" under the  Resource  Conservation and  Recovery
Act  (RCRA)  and  has  also  proposed  regulations for  the  treatment,
storage,  and  disposal  of  these  wastes  (43 FR 58946,  December  18,
1978).  The EPA  is currently conducting an extensive  study  of solid
wastes  from  mines,   including  uranium  mines  at   the   request   of
Congress.   If  warranted,  further  regulations  on  mining  would  be
promugated.
 *The  radium-226 concentration of most soil and rock is about 1 pCi/g.

-------
                                 13

     Use of Wastes in Building Construction

     Using wastes containing  elevated levels  of  radium-226 as  land
fill  for  residential  construction   or   building  homes  on   land
contaminated by these wastes can greatly increase  the chance of  lung
cancer to  individuals  living  in  these structures.  Radon-222  formed
from  the  decay of  radium-226 is  an   inert  gas  that  readily  seeps
through foundations, floors, and walls and accumulates in the  inside
air  of  a  house.    The  radon-222  then  decays  to  daughter products
which, when  breathed,  will lodge  in  the  lungs and cause  radiation
exposure to the lung tissues.  For example,  the use of uranium  mill
tailings  in  the  construction  of homes  in  Grand Junction,  Colorado,
resulted  in radon-222  decay product concentrations inside  the homes
that  required  a  Federal-State   remedial   action  program  for   the
affected   structures   (Public  Law  92-314).    These  mill  wastes,
however,  contain much  higher  concentrations  of radium-226  than  mine
wastes.   A survey  of homes in Florida on reclaimed land containing
wastes from phosphate  mining  showed about 20 percent of these homes
have  radon-222  decay  product  concentrations  in  excess  of  0.03
working level  (WL).*  Lifetime residency  in  a home with this level
could  increase  the chance of  lung   cancer   by  as  much  as  4  in
100--thus doubling the normal  risk of  lung cancer.
      The  mechanisms by which uranium  mine  wastes may cause  health
risks  are similar  to  those  which  have occurred  from  uranium  mill
tailings and phosphate wastes.  Although uranium mine wastes usually
have  a  lower  radionuclide  content   and  are  less  suitable  as  a
construction material  than  the  sand-like  tailings, these wastes  are
still  a  potential   health  hazard  to  individuals  if effective waste
disposal  methods are  not  used.    EPA  has  provided  to  the   States
survey reports of radiation anomalies that may  be  due to use of  mine
wastes  in construction and will   continue  to  support  State  use  of
this data.
*A working  level  (WL)  is any combination of  short-lived  radon  decay
products  in  one  liter  of  air  that  will  result  in  the  ultimate
emission  of alpha  rays  with a  total  energy  of 130,000  MeV.    The
working level expresses  a  concentration of  radioactivity in  the  air,
not  how much radiation  a  person receives.   EPA estimates  that  the
average working level in U.S. homes is about 0.004 WL.

-------
                                 14

                             SECTION  III


                           INACTIVE MINES


NUMBER OF MINES


     There  are  about  3400  inactive  uranium mines  in  the  United
States.   A  list  of these  mines  developed  from  computer  listings

maintained  by  the  U.   S.   Department   of  Energy  is  presented  in
Appendix  F  including the  type  of  mine, location,  and owner.   The

following table  summarizes  the  numbers  and  types  of inactive  mines
by State:


                               Table  2

            Location of  Inactive Mines in United States


     State            Surface         Underground       Other

     Arizona            135                 189            2
     Colorado           263                 902           52
     New Mexico          34                 142           12
     South Dakota       111                  30            0
     Utah               378                 698           17
     Wyoming            223                  32           10
     Other              108                  43            8

     Total             1252                2036          101



HEALTH IMPACT OF AIR EMISSIONS- INACTIVE  MINES


     Radiological Impact


     Radionuclide  emissions  into  air at  inactive  mine  sites  are

small compared  to  the  emissions from active  mines according to  our
estimates  of  model  mines.    The   principal   radionuclide  emitted,

-------
                                 15

radon-222, emanates  from  unsealed mine  vents,  portals and  residual
waste piles.  This causes  only small increases  in  the risk of  lung
cancer to  individuals  living near these  mine  sites.   Utilizing  the
same models  as  for the active  mines,  we  estimated  risks of  cancer
from radon-222 emissions to air from our model  inactive mines.
     By multiplying the risks  from our  model  mines by the  number  of
inactive  mines  of each  type,  we  extrapolated the  total  number  of
potential cancers from  all  inactive  mines.  This procedure  provides
only a very  rough approximation  of the  total  risk from all  inactive
mines.
     By  these  estimates,  radon-222  emissions  from inactive  uranium
mines would produce the following cancer risks:

          Individuals living for  a lifetime  1  mile from  an  inactive
          mine  would  have  an  increased  chance  of  lung  cancer  of
          about 2-3 in 100,000.

          The  amount  of  radon-222  released   each  year  from   all
          inactive uranium  mine  sites  would  cause  about  0.1  lung
          cancers in the regional  population  around  these  sites.

     Nonradiological  Impacts

     We  did  not  identify  any  significant health impact  associated
with  nonradiological air  emissions at  inactive  uranium  mines.   Our
estimates of dust emissions  from wind  erosion of waste piles  showed
that  insignificant  concentrations  of   nonradiological   pollutants
would exist in air at these inactive sites.

-------
                                 16

HEALTH IMPACT OF WATER EMISSIONS-INACTIVE MINES

     The extent to which inactive  surface  and  underground mines  harm
water quality  is poorly understood.   Ground  water  in contact  with
ore   bodies   and   consequently   in   mines    typically    contains
radionuclides  and  trace elements,  and  the  flow of  the  water  away
from  the  site  carries  dissolved  and   suspended  radionuclides  and
trace elements.
     Site  specific  studies  are needed  to  determine  the present  and
potential  impacts  of  inactive uranium mines  on both  surface  and
groundwater quality.  As with  active  mines,  the  potential exists  for
contamination  of drinking  water  supplies.    States  may  desire  to
conduct sampling of drinking water  at a few  sites  in  the  vicinity of
inactive mining districts to provide  data  to evaluate  whether such a
potential is valid.

HEALTH IMPACT OF SOLID WASTES-INACTIVE MINES

     Surface Mines

     We  estimate that  over  1 billion tons  of solid  wastes  were
generated  at  surface  uranium mines   through  1978.    These  wastes
consist of  sub-ore  and  overburden.   The sub-ore, which may  comprise
about 3 percent of  the  total wastes,  contains  significantly  elevated
concentrations of radium-226 (up  to 100 pCi/g).*  Although the over-
burden  contains  much  lower concentrations  of  radium-226  than  the
sub-ore, large quantities  of  these wastes can contain  radium-226 in
concentrations in excess of 5  pCi/g~the  level  EPA has proposed be
used to judge whether wastes should be  considered  as  a candidate for
designation  as hazardous  waste  under  RCRA.   Such  a  determination
would require  that  specified disposal methods  be  developed for these
mine wastes.
*The radium-226 concentration of  normal  soil  and  rock is about 1 pCi/g.

-------
                                 17

     In many  surface  mines opened  since  1970,  the general  practice
is to  backfill  the mined-out pits  with wastes as  part  of a  recla-
mation  program.    However,  at  most  older  inactive  surface  mines,
little or no reclamation was done.

     Underground Mines

     We  estimate  that   about   30  million  tons  of   solid   waste
consisting mostly  of  sub-ore were  generated  at  underground  uranium
mines  through  1978.   As  in  surface  mining,   the  sub-ore  contains
significantly   elevated   concentrations   of   radium-226   (up   to
lOOpCi/g).   There has  been  very  little  reclamation  at  inactive
underground  mine  sites,   so  most  of  these  wastes  remain  on  the
surface at these sites.

     Use of Hastes in Building Construction

     As  discussed  in  the  section  on active  mines,  uranium  mine
wastes  would  present  a  significant hazard to  individuals if  homes
are  built  on land contaminated  by these wastes  or if  these  wastes
are  used in construction materials  for homes.   Individuals living  in
these  homes could have  an  increased chance  of  lung  cancer  from
breathing  radon-222 decay  products.    The  extent  to  which  uranium
mine wastes have previously been used  for  these purposes is not well
known.
     However, some information  is  available which shows  that  uranium
mine   wastes  may  have   been  widely  used   as   landfill   in  the
construction  of  various  types  of  buildings.   In  1972  EPA and  the
former Atomic Energy Commission (AEC)  tried to  identify  locations  of
higher-than-normal levels  of  gamma  radiation in an  attempt to  locate
uranium mill  tailings.  During this  study, over 500 locations were
identified  where  uranium  ore  was  believed   to  be  the  source  of
elevated  gamma   radiation.   Since   it is  unlikely  that  ore-grade

-------
                                 18

material  would  be  used  as  landfill,  we  suspect  that uranium  mine
wastes  (perhaps  sub-ore) may  be  the  source of  the  abnormal  gamma
radiation at these sites.
     In  order to  better define  the  off-site  use  of uranium  mine
wastes, EPA  is  studying  the extent  to which these wastes  have  been
used  away  from the  mine  sites  for  landfill  or  in  construction
materials  for  use  in   homes.    If  mine  wastes  were  involved  in
construction of homes, a health risk  from radon-222 emissions  would
exist.   A preliminary  survey   has already  been  completed and  the
information   has   been   shared   with  the   interested   agencies  in
appropriate States.

-------
                                 19

                             SECTION IV

                   CONCLUSIONS AND  RECOMMENDATIONS
     The evaluation  of  the potential impacts  of  uranium mining  was
performed   largely   by  means   of   analytical   studies  of   model
facilities.   We   believe  that   the   results   give   an   adequate
representation of the industry.  In  order  to determine  the  extent of
possible problems,  our  studies  were specifically  designed to  give
conservative results.  It  should be  recognized that  actual  mines  may
operate  under conditions  producing  substantially  smaller  impacts
than the results presented.
     Compared to  uranium milling,   health  and  environmental  effects
of uranium mining  are  not as well  understood,  despite  the  existence
of over  3000 active and inactive  mines.   We  have  noted  throughout
this  report  instances  of  the  absence  or inadequacy  of  pertinent
information.

CONCLUSIONS

     Solid Wastes

     Solid uranium mining  wastes are  potentially  hazardous  to  health
when used as building materials or when  buildings are constructed on
land  containing  such  wastes.   The  hazard arises  principally  from
increased risk of lung cancer due to  radon-222.   In  a 1972  survey of
communities  in  uranium  milling  and mining   regions,  EPA  and  the
former Atomic Energy Commission  found more than  500  locations  where
such wastes had been used.

-------
                                 20

     Airborne Effluents

     a)   Individuals  living  very   near   active   underground   mine
exhaust vents would  have  an  increased risk of lung cancer  caused  by
exposure to  radon-222 emissions.   Surface  mines and  in situ  mines
are  less  hazardous,  and  inactive  mines   do  not  have  significant
radon-222 emissions.   Other  airborne radioactive emissions  from all
types of mines are judged to be smaller.
     b)  The number  of   additional  cancers  committed  per year  in
regional populations  due  to  radionuclide  air  emissions  from  the
approximately 340 active mines and  3300  inactive mines was  estimated
to  be  about  0.6   cancers   in   1978.   This   number   of  estimated
additional   cancers  is  small,  about  one-third  of  the  estimated
additional   cancers  in regional  populations due  to radon  emissions
from the 24  inactive uranium mill tailings piles addressed by  Title
I  of  the  Uranium Mill Tailings  Radiation  Control  Act.   (These  mill
tailings piles represent  about 13 percent  of all tailings  currently
existing due  to  U.S.  uranium  milling  and  mining).   These  potential
effects  are  not  of  sufficient  magnitude  to  warrant  corrective
measures,    especially   considering   the   large  number   of   sites
involved.
     c)   The  following   emissions  were   judged   to  cause   an
insignificant health risk at all  types of mines:
          1.  airborne nonradioactive trace metals
          2.  airborne combustion products  from heavy-duty equipment
              operations
          3.  nonradioactive emissions from in situ  leach sites
     d)  Airborne dust near  large  surface mines  (primarily  caused  by
vehicular  traffic)   may   exceed   the National  Ambient  Air  Quality
Standard for particulate matter.

-------
                                 21
     Waterborne Effluents

     a)   We  estimate   that  an  insignificant  health  risk  accrues
currently  to  populations  from  waterborne  radioactivity  from  an
average existing mine.
     b)   Uranium mine  dewatering  and  water  discharges,  which  are
increasing as more  and  deeper mines  are  created,  may in  the  future
have  significant  effects  on  water  quality.    Current  treatment
practices are controlling  the  release of radioactivity  into  surface
waters.
     c)   Water   in  inactive  surface  and underground  mines  usually
contains   radionuclides  and   trace   elements   in   concentrations
comparable  to  ground  water  in  contact  with  ore  bodies.    Some
abandoned underground  mines  in certain areas of  Colorado and  Utah
probably  discharge  such  waters  to  nearby   streams   and  shallow
aquifers.  Available data  is not  sufficient  to  conclude  whether  or
not there is a problem.
     d)   We  could  not  determine,  using models,  that  there  is  no
health  hazard  to individuals who  drink water drawn from  surface  or
underground  sources.  Water  discharges from  active mines  to  nearby
streams   and   stream   channels  may  extensively   recharge  shallow
aquifers, many  of which  are  either  now  used or could  be used  for
drinking water.  Such determinations  must be  made on a  site-specific
basis,  and  take account of the  additive  effects of multiple  mines.
These  studies  can  be   made   easily  a  part  of  State  or  utility
surveillance programs.

     Exploratory and Development Drilling

     Harm  from  effluents  due  to   exploratory   and   developmental
drilling  is  probably  small  compared  to effects  of  operating  mines.
Under   current   regulations   and    practices,   however,   aquifers
penetrated at  different levels can mix,  creating  the potential  for
degrading good quality groundwater.

-------
                                 22

RECOMMENDATIONS TO CONGRESS

     1)   Based on  this  study,  we do  not  believe at this  time  that
Congress  needs  to  enact  a  remedial  action  program  like  that  for
uranium  mill  tailings.   This  is  principally  because  uranium  mine
wastes  are  lower   in  radioactivity  and  not  as   desirable   for
construction purposes  as  uranium  mill  tailings.   Nonetheless,  some
mining  waste  materials  appear  to have  been moved  from the  mining
sites, but not to the extent that mill tailings were.
     2)    Some  potential  problems  were  found  that  might  require
regulatory  action,  but  none   of  these  appear   to   require   new
Congressional  action at this time.

-------
                                 23

                              SECTION  V

                           OTHER FINDINGS

     1)   Regulations may  be  needed  to  control  wastes  at  active
uranium mines  to preclude  off-site  use and  to minimize  the  health
risks from these materials.   These regulations  would  need  to address
the  use  of  the  materials  for  construction  purposes  as  well  as
ultimate disposal of the materials.
     EPA  proposed  such  regulations  in  1978  under  the  Resource
Conservation and Recovery  Act  (RCRA).   In  1980,  Congress  amended
RCRA  to  require  further  EPA  studies   before  promulgating  general
regulations for mining wastes.   An  EPA  study by the  Office  of  Solid
Wastes on  all  types of  mines, including uranium mines,  is currently
being conducted.  The  amendment does not  affect  EPA's  authority  to
regulate  use of  uranium mine  wastes  in construction  or reclamation
of lands containing such wastes.
     2)   Standards  are  needed  to  control   human   exposure   from
radioactive air  emissions  from  uranium  mines.   This  is  principally
because  of potential  exposure  to  individuals  living  near  large
underground  uranium  mines   rather   than  concerns   regarding   the
exposure  of regional  populations.   We  have proposed  such  standards
under Section 112 of the Clean Air Act.
     3)  EPA has conducted  two field  studies in 1972  and  1978  which
define possible  sites  at which  mine  wastes  may  have  been used  in
construction or  placed  around buildings.   The  information  developed
in  these  studies has  been  sent to State  health  departments.   The
States  should   conduct  follow-up   studies,   as   appropriate,   to
determine whether there are problems at these sites.
     4)   The adequacy  with  which  NPDES permits protect individuals
who may obtain drinking  water near the  discharge points  for uranium
mine  dewatering  should  be  evaluated by States.   Under the  Public
Water Systems provision of the  Safe Drinking  Water Act,  radionuclide
standards now exist for drinking water.

-------
                                 24

     5)  Some  site  specific studies  should  be considered  by  States
to  determine   the  extent  to which  inactive  uranium mines  may  be
significant water pollution sources.
     6)  States with  uranium mines should determine  the  feasibility
of  controlling   fugitive   dust   from   large   surface   mines   and
incorporate the recommendations in State Implementation Plans.
     7)  States should require borehole plugs  in  drilling  operations
that  will   prevent  interaquifer  mixing  (exchange)  and  also  seal
drilling holes at the surface.

-------