United States
 Environmental Protection
 Agency
 Industrial Environmental Research
 Laboratory
 Cincinnati OH 45268
 Research and Development
EPA-600/S7-84-022  May 1984
 Project Summary
 Coal  Mine  Related  Stream
 Sediment  Geochemistry in
 Southern  Illinois

 William C. Hood, Paul D. Robinson, Jean B. Chruscicki, and Thomas A. Delfino
  The stream sediment geochemistry of
 several elements, specifically cadmium,
 cobalt, copper, iron, manganese, nickel
 and line, has  been examined in a six-
 county area of Southern Illinois. This
 area has been greatly impacted by coal-
 mining activities. Arsenic and chromi-
 um were also  investigated, but only in
 isolated areas. The survey of these
 elements in stream sediments indicates
 that in most areas having four times the
 median value for cadmium, cobalt, iron,
 nickel  and  zinc, are  generally
 located downstream from areas of coal-
 related uses. In detailed study of these
 streams, there occur marked relation-
 ships among the pH of mine drainage
 water, the concentrations of metals in
 the water, and the concentrations of
 metals in corresponding stream sedi-
 ment. Water with low pH reaches sea-
 sonal summer highs in metal content
 and can enter streams already carrying
 large concentrations of metals. In those
 parts of a mine-impacted stream where
 low pH  is maintained, metals can be
 leached  from  the stream sediment to
 further increase the concentrations in
 water. On the other hand, if the pH of a
 stream is increased, metals will tend to
 precipitate out of the water and become
 part of the stream sediment.
  This Project Summary was developed
by EPA's Industrial Environmental Re-
starch Laboratory, Cincinnati, OH, to
announce key  findings of the research
project that is fully documented  in a
separate report of the same title  (see
Project Report ordering information at
back).
Background
  Southern Illinois is an area that for
many years has been extensively mined
for coal. Coal-bearing Pennsylvanian-
aged rocks crop out in a broad band that
curves gradually across the southern part
of the state. Where the coal beds in these
rocks are shallow, surface mining has
been widespread. North of  the shallow
outcrop area, where  the coal beds are
deeper, underground mines are abun-
dant. As of mid-1971,21,987 hectares of
the six-county area of this study had been
affected by surface mining activities and
surface disturbances related to under-
ground mining. This  amounts to three
percent of the land area in these counties.
  Prior to passage of various State and
Federal reclamation laws, some of the
mining practices used in Illinois resulted
in the creation of problem  sites which
have generated large amounts  of acid
mine drainage. In the southern Illinois
area, acid mine drainage typically arises
in one of two general settings. First, old,
coarse refuse (gob) piles and fine refuse
(slurry) impoundments which have been
exposed  to the weathering processes
have created areas of intense production
of acid drainage and  related pollutants.
Second, there are some areas in which
the overburden has a high potential for
the production of acid drainage and little
potential to  neutralize it. Strip mines
exposing such material to air and water
can create large non-point source areas
of acid mine drainage.
  The polluted waters  generated from
these sources are known to carry appreci-
able concentrations of several potentially

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"SW?^*
   toxic trace  elements.  Monitoring  pro-
   grams by the Illinois Environmental Pro-
   tection Agency, the  Greater Egypt Re-
   gional Planning and Development Com-
   mission, and numerous studies of indi-
   vidual sites, have shown that appreciable
   quantities of zinc, cadmium, nickel, co-
   balt, iron, manganese and minor amounts
   of copper in the streams are draining
   such areas.  However,  not all  of the
   contaminants moved by a stream are
   dissolved in the water. Many are carried
   as part of the paniculate suspended and
   bed  load of a stream, to be picked up,
   dropped, or rolled along as circumstances
   dictate. The literature suggests that such
   elements may  be either removed from
   solution to become part of the particulate
   load or may be dissolved from solids and
   reintroduced into the water, depending
   upon the chemical environment. Indeed,
   some studies suggest that much of the
   trace element load of a stream is carried
   in such  a  non-dissolved state.  Thus, a
   monitoring program that examines only
   the dissolved portions of a polluted stream
   may miss large quantities of metals being
   transported  in another  manner.  This
   study attempts  to ascertain the extent of
   distribution  of metals  in the stream
   sediment of the mine-impacted portion of
   southern Illinois, and to determine the
   conditions under which  metals  move
   from the water to become a part of the
   sediment, and vice versa.

   Approach
     This investigation of the  geochemistry
   of cadmium and other metals related  to
   coal mining is restricted to a six-county
   area  of  southern Illinois.  The counties
   involved are Gallatin, Jackson, Perry,
   Randolph, Saline, and Williamson (Figure
   1). The amount of  land that has been
   disturbed by surface mining  and the
   surface effects of underground mining of
   coal in these counties range from  over
   seven percent  in Perry County to less
   than one percent in Gallatin County. Table
   1 indicates the amou nt of surface disturb-
   ance related to  coal-mining activities.

   General Geology
     Coal-bearing formations of the Penn-
   sylvanian age crop out across southern
   Illinois in a west-to-northwest-trending
   arc  (Figure 2).  Their dip  is toward the
   north and northeast, resulting in an
   older-to-younger  progression of forma-
   tions from south to north. This simple
   pattern is complicated somewhat  by
   several  structural  features, including
   several  fault systems  and two major
                                           Study Area
 Figure 1.    Location of study area.
Table 1.    Areas Disturbed by Coal Mining
           Activities

           Hectares in   Area
   County     County  Disturbed Percent
Gallatin
Jackson
Perry
Randolph
Saline
Williamson
84,955
1 56,181
114,740
153,851
99,459
1 10,596
6OO
1.983
8.222
2.195
3.846
5.140
0.71
1.27
7.17
1.43
3.87
4.65
folds. Of the fault systems within the
study area, the Cottage  Grove Fault
System, the Wabash Valley Fault System,
and  the Fluorspar Area  Fault System
displace the coal beds on the order of a
few meters to a few tens of meters. The
Shawneetown Fault, on the other hand,
has displacements estimated to be on the
order of hundreds to thousands of meters.
South  of the Shawneetown Fault, the
coal-bearing rocks are folded into a U-
shaped outcrop pattern which has brought
several of the coals to the surface in a
relatively small area. When encountered.
all of these features affect the mining of
the coals to some extent and at times
establish the physical limits of a mining
operation.
  Another structural feature of major
importance is the DuQuoin Monocline.
Unlike the previously mentioned features,
this structure was active during the time
of deposition of the Pennsylvanian rocks
and separated a  relatively  stable area
which was dominated by shallow marine
influences on  the west (western shelf
area)  from one on the  east which was
gradually subsiding. The subsiding east-
ern area was the site  of active delta
building during the time of coal deposi-
tion. The different types of environments
resulted in somewhat  different over-
burden  rocks associated with the coal
beds,  and this in turn has influenced  the
water quality in the different parts of  the
area.  West of the monocline, there  are
numerous limestone beds;  east of  the
structure limestones are sparse.
  The important coal-bearing formations
are the Spoon and the Carbondale Forma-
tions. The Spoon Formation consists
largely of sandstone, siltstone, and gray

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                                                             Geology of Study Area
                                                        Cottage Grove
                                                        Fault System
 P - Pennsylvania!!
     Pb - Bond
     Pm - Modesto
     PC - Carbondale
     Ps - Spoon
     Pa - Abbott
     Pcv - Caseyville
M - Mississippian
                                                                                                      Shawneetown
                                                                                                         Fault
                                                                                                    Eagle Valley
                                                                                                     Syncline
Figure 2.   Geology of study area.
shale,  with very little limestone.  Two
important coal beds, the Davis and De-
Koven coals, are commercially important
in the southern parts of Williamson and
Saline  Counties. The fact that there is
only about six meters of material between
these two coals allows them to be mined
simultaneously. At some locations, the
stratigraphic sequence between the coals
is partially made up of a pyrite-rich black
shale that contains up to twelve percent
sulfur. When exposed at the surface, this
pyritic  shale can produce considerable
amounts of acid. Extensive mining of the
Davis and DeKoven  coals has produced
areas of intense pollution because of this
unfortunate stratigraphy.
  The Carbondale Formation overlies the
Spoon Formation and differs from it by
having larger proportions of limestone
and shale. The limestones tend to become
more abundantly higher.in  the strati-
graphic section and west of the DuQuoin
Monocline. Two important coals are also
present in this formation. These are the
Harrisburg  (Number  5) and  the  Herrin
(Number  6) coals. The Number 6 coal is
stratigraphically  above the Number  5.
East of the DuQuoin Monocline, in the
area of Williamson and Saline counties,
the stratigraphic interval between the
two coal beds is on the order of 43 meters,
and the two coals are mined separately.
The generally low dip of the strata in this
area results in the outcrop lines of the two
coals being separated by as much as 1.5
kilometers, giving rise  to two series of
parallel strip mines. Further to the west,
particularly in the vicinity of the DuQuoin
Monocline, the stratigraphic interval be-
tween these coals becomes much thinner.
In Perry and  Randolph counties,  only
about 10 meters of rock separate the beds
and the two coals are commonly removed
in a single mining operation.


Elemental Distribution Results
  The  regional  distribution of metals
within the study area are discussed on an
element-by-element basis.

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Cadmium
  In the Saline  River  area, there are
numerous high cadmium values  in the
stream  sediments. Most of these are
concentrated along the  South Fork, with
another area of concentration  in Eagle
Creek. Two high values were noted in the
westernmost part of the area; these occur
downstream from a coal-fired powerplant.
Another cluster of high  values occurs in
the northeast part of the basin, associated
with underground coal mines in the area.
In the Crab Orchard Creek area, numerous
high values of cadmium  occur. As before,
clusters of high points are located  down-
stream from coal mining activities. A pair
of high values occurs in the southern part
of  the  area.  Although  no  mining is
presently taking place in that area, several
small and very old mines are scattered
around the hills, and it is possible that
these two points are downstream from
one or more of these unmapped  mines.
Not shown on the map are several  under-
ground mines in the central part  of the
area. Several of the high values are below
the  old underground  mines.  In  the
Beaucoup Creek area, only four scattered,
high cadmium values occur, and three of
these are clearly associated with strip
mines. The fourth occurs in the northern-
most part of the area and does not appear
to be related to mining activities. In the
Marys River area, several high values are
present. Virtually all of these are adjacent
to or downstream from mines.

Copper
  In the Saline River area, only  a few
anomalously high copper values  occur.
Of  these,  two are downstream from a
known gob pile, one is adjacent to  a strip
mine, and the fourth is  not known to be
related to mining. Three high values occur
in the Crab Orchard Creek area. The first
is several  kilometers downstream from
mines;  however, there are  many low
values between it and  the  mines. The
other two  are scattered, apparently un-
related to mines. The two high concentra-
tions which appear in the Beaucoup Creek
area  are  scattered  and are spatially
unrelated to mining. Finally, in the  Marys
River area, no high values occur, although
a few scattered intermediate values show
no relationship to mining.

Cobalt
  In the Saline River area, six high cobalt
values are present. One of these, located
in the north center portion of the area, is
in the vicinity of an old gob pile  and is
likely related to it. A second is located
near the mouth of Eagle Creek, a stream
contaminated by mining, while a third, in
a tributary of the Saline  River, receives
drainage from a mining area. Two anom-
alously high values do not appear to be
spatially related to coal  mining.  In the
Crab Orchard Creek area, there are four
more high values. Three of  these four
locations are downstream from  mining
activities; however, the fourth is not. In
the Beaucoup Creek  area, three high
values occur in the northern  part of the
area butappeartobe unrefcrtwdto mining.
Lastly, in the Marys River area, the one
high value is in close proximity to a strip
mine, but is upstream from the mining
activity.

Iron
  In the  Saline River area,  only three
exceptionally high iron values occur. Two
are downstream from mines while one is
not. Several intermediate concentrations
are  located  downstream from  mining
activities. In the Crab Orchard Creek area,
a few high values are present, all of which
occur downstream from coal mines. No
exceptionally high values occur  in the
Beaucoup Creek area or in  the  Marys
River area.

Manganese
  In the Saline  River area, four high
values of manganese occur in scattered
locations,  three of which occur  down-
stream from coal mines. If intermediate
values are considered, only a few are
downstream from coal  mines. Seven high
values occur in the Crab Orchard Creek
area, mainly downstream from mines;
intermediate values occur frequently. Five
high values occur in the Beaucoup Creek
area, although only  two of these are
downstream from mines. Intermediate
values appear to be unrelated to mining.
Finally, two high manganese values occur
in the Marys River area. Both of these are
adjacent to strip mines, but do not appear
to be downstream from them. Interme-
diate values  are randomly  scattered
across the entire area.

Nickel
  It can be seen that most of the twenty
anomalous concentrations of nickel in
the Saline  River area  and the Crab
Orchard Creek area are downstream from
coal mining  activities. In  the Beaucoup
Creek area, there are only two high
values, one of which is downstream from
a coal mine.  In the Marys River area, the
only high value is adjacent to a coal strip
mining area.
Zinc
  Zinc is similar  in  geochemistry  to
cadmium, and not surprisingly the distri-
bution of these two elements is similar.
High zinc values are present in the saline
river area, mostly downstream from strip
mining or  downstream  from the coal-
fired  power plant  located in the area.
Other high concentrations occur in Eagle
Creek, an area heavily impacted by min-
ing. Another neighborhood with high zinc
values is located near an old gob pile in
the northeast part of the area. Many high
values also occur  in the Crab  Orchard
Creek area. With few exceptions, these
are closely associated with mining. High
values in the Beaucoup Creek area, with
two exceptions, are also closely associ-
ated  with mining.  Lastly, the one high
value of  zinc found in the  Marys River
area is downstream from a strip mine.

Conclusions
  The stream sediment geochemistry of
several elements; specifically, cadmium,
cobalt, copper, iron, manganese, nickel,
and zinc, has been examined in a six-
county area of Southern  Illinois that has
been  greatly impacted  by  coal-mining
activities.  Arsenic  and chromium  were
also  investigated,  but only in  isolated
areas.
  A regional survey of these elements in
stream sediments  indicates that  most
areas of anomalously high concentrations
(four times the median value) of cadmium,
cobalt, iron,  nickel and zinc generally
occur downstream  from coal mines or in
other areas of  coal-related  land  uses.
Most such  anomalously high  stream
sediments are within eight kilometers of
the coal-related area. Only  manganese,
and  to a  lesser extent copper,  show
distribution patterns unrelated to mining.
  In three streams singled out for more
detailed study, marked relationships exist
among the pH of mine drainage water,
the concentrations of metals in the water,
and  the  concentrations of metals  in
corresponding stream sediment. Water
with  low  pH shows seasonal summer
highs  in  metal content  and can  enter
streams already carrying large  concen-
trations of metals that have either been
released during the oxidation of pyrite or
leached from the rocks  with which the
acid drainage has  come  into contact. In
those parts of a mine-impacted stream
where low pH is maintained, metals can
be leached from the stream sediment to
further increase the concentrations  in
water. On the other hand, if the pH of a
stream is increased, metals will tend to

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precipitate out of the water and become
part of the stream sediment. The precipi-
tation reactions can occur at considerable
distances downstream from the source of
pollution, and account for the observed
regional distribution of anomalously high
concentrations of metals in sediment.
  Based on the data obtained  in  this
study, the following  conclusions can be
made:
 Various metals such as arsenic, cadmi-
   um, cobalt, copper, iron, manganese,
   nickel, and zinc  are  present in the
   rocks of the  coal mining region of
   southern Illinois, in amounts generally
   equal to or slightly greater than the
   content  in similar rocks around the
   world.
 Sulfuric  acid created by the oxidation
   of pyrite can mobilize these elements,
   allowing them to move into nearby
   surface drainages.
 Once  in the  stream, the fate of a
   particular metal depends on geochem-
   ical factors,  such as pH, which de-
   termine whether it will stay in solution
   or become a part of the stream sedi-
   ment.
 Those parts  of streams less than 8
   kilometers downstream from coal min-
   ing activities frequently have trace
   element contents in bottom sediment
   significantly higher than those parts of
   the stream not influenced by coal-
   related activities.
  Parts of streams having low pH values
consistently have higher concentrations
of the trace elements in water than do
areas with high pH values.
  Sampling sites with low pH values
commonly show a strong seasonal varia-
tion of concentration  of  elements in
water, marked by an increase in concen-
tration of all trace elements in the summer
and fall months. Sites with high pH
values do not develop a seasonal trend;
instead they have various peaks and lows
in concentration occurring throughout
the year.
  Sites with low pH, and a seasonal trend
in water quality, show strong interele-
mental behavioral similarity. Conversely,
sites with high pH values that lack the
seasonal trend do not have strong inter-
elemental behavioral similarity.
  Concentrations of all trace elements in
water  decrease with greater distance
from  the source, due to dilution from
additional surface water or groundwater
and/or to the precipitation of elements
 iut of solution.
  Rainfall may dilute the concentrations
of the trace elements in water.  The
influence of this factor increases in
streams of greater drainage area.
  Sampling  sites with low pH values
consistently  have lower concentrations
of the trace elements in stream sediment
than sites with high  pH values.
  None of the streams studied showed
significant seasonal variation for  trace
elements in sediments. Most values
fluctuate throughout the year, with erratic
peaks and lows. However, high or peak
values  occur more often  in  summer
months.
  Concentrations of most of  the  trace
elements in sediment  decrease  with
increasing distance  downstream from a
polluting source. When  high pH-high
sediment concentration streams mix with
low  pH-low sediment concentration
streams, the resulting values for metals
in sediment are not  necessarily  inter-
mediate. Some elements are  of  lower
values than  either contributing stream,
suggesting a dissolution of these ele-
ments from the sediment. Iron and chro-
mium are frequently in higher concentra-
tion in the sediment below the confluence
than in either contributing stream, indi-
cating precipitation of these  elements.
The specific behavior of the metals mainly
depends on the pH of the water below the
mixing zones.
  The  higher trace  element content  of
stream sediment below coal mines is a
result of leaching of the elements in  or
near the mines by acidic water coupled
with  reprecipitation  when the  acidic
water is neutralized. Consequently, it is
recommended  that monitoring stream
sediment for trace element pollutants not
be required, because  pH and trace ele-
ment content in the mine effluent will
control mine-related downstream chang-
es in the trace element content of the
sediments.
   William C. Hood, Paul D. Robinson, Jean B. Chruscicki, and Thomas A. Delfino
    are with Southern Illinois University, Carbondale, IL 62901.
   Thomas J. Powers is the EPA Project Officer (see below).
   The complete report, entitled "Coal Mine Related Stream Sediment Geochemistry
    in Southern Illinois," (Order No. PB 84-153 444; Cost: $13.00, subject to
    change) will be available only from:
          National Technical Information Service
          5285 Port Royal Road
          Springfield, VA 22161
          Telephone: 703-487-4650
   The EPA Project Officer can be  contacted at:
          Industrial Environmental Research Laboratory
          U.S. Environmental Protection Agency
          Cincinnati, OH 45268

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