Metal accumulation in voles from an acid mine drainage impacted wetland
by Thomas Lindsey Zavitz
A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Land
Rehabilitation
Montana State University
© Copyright by Thomas Lindsey Zavitz (1990)
Abstract:
Concentrations of cadmium, copper, and zinc in the kidneys of meadow voles (Micrttus
pennsylvanicus) and in the whole bodies of shrews (Sorex spp.) from an acid mine drainage impacted
wetland and a control wetland were determined. Cadmium and copper levels were significantly
elevated in kidneys of voles from the contaminated wetland; zinc levels were not elevated. Shrew
whole body cadmium levels were also significantly higher while copper and zinc whole body levels
were not significantly different compared to animals from the control area. The elevated levels of
cadmium demonstrate the potentially hazardous uptake of this element. However, cadmium and copper
levels were not considered to be accumulating to hazardous levels in voles or shrews or to be a risk to
animals that prey on them. M ETAL ACCUM ULATION IN VOLES
FROM A N ACID MINE DR A IN A G E IMPACTED WETLAND
by
Thomas Lindsey Zavitz
A thesis submitted in partial fulfillment
o f the requirements for the degree
of
Master of Science
in
Land Rehabilitation
M ONTANA STATE UNIVERSITY
, Bozeman, Montana
^
June 1990
ii
APPROVAL
of a thesis submitted by
Thomas Lindsey Zavitz
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bibliographic style, and consistency, and is ready for submission to the College of
Graduate Studies.
AL I 1 9 9 0
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Approved for the Major Department
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fd
Date
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Approved for the College of Graduate Studies
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Date
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U
D ate
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iv
TABLE OF CONTENTS '
Page
TABLE OF C O N T E N T S ..............................................................
iv
LIST OF TABLES .........................................................................................................
vi
LIST OF FIGURES .............................................. ................. ............ ........................
vii
A B S T R A C T ...................................................................
viii
IN T R O D U C T IO N ...................................................................................................
I
LITERATURE REVIEW ............................................................................................... 5
Animals as Indicators of Environmental Metal Contamination .............
5
Copper, Zinc and Cadmium Accumulation in Small Animals . . . . . . .
6
Toxicities and Target Organs . . . ....................................................................
10
Metal Movement Through Food Chains . . . ..............................................
12
14
14
14
MATERIALS A N D M E T H O D S ...................................................................
Selection o f an Indicator Species . .................................................................
Selection o f Trapping A r e a ........................................................
T ra p p in g ................................... .......................................................................... .
Laboratory Analyses ...................................................................
Statistical M e th o d s ...............................................................................................
17
17
19
DESCRIPTION OF ST U D Y A R E A .........................................................................
General L o c a tio n .................................................................................................
Natural Environment .............................................. i . . ..................................
Carbonate Mine History and Geology .........................................................
Vegetation on Study S i t e s ............................................................................. .
Collection Sites ...................................................................................................
20
20
20
21
22
23
RESULTS ..........................................................................................................................
Trapping S u c c e s s ...................................
M etal L e v e l s ......................................................................... ............................. .
24
24
25
DISCUSSION . ......................................................
Microtus D e n s it ie s .............................
Tissue Metal C on centration s................................
Hazard to M icrotu s...............................................................................................
Possible Hazard to Higher Trophic Levels .................................................
28
28
29
30
31
V
TABLE OF CONTENTS - Continued
Page
SUMMARY AND C O N C LU SIO N S...................................................................
35
LITERATURE CITED .................
37
A PPEN D IC ES...........................................................................................................
APPENDIX A - Statistical Data ................. ............................................
APPENDIX B - Data Tables .....................................
43
44
46
vi
LIST OF TABLES
Table
Page
1. Metal concentrations (/xg/g dry weight) in vegetation from the study site
(Swamp Gulch wetland) and the background site (Hardscrabble Creek). .
3
2. Maximum tolerable levels of dietary minerals for domestic animals
(National Academy of Sciences 1980)............
3
3. Metal concentrations (jug/g wet weight) in M. pennsylvanicus kidney
tissues............................................................................: .............................
4. Metal concentrations (/ig/g
wet weight) in
wholebody Sorex
26
spp.
5. Metal concentrations (jug/g
wet weight) in
M.pennsylvanicus
kidney
tissues within the Swamp Gulch wetland........................i ............................. 27
6. T-test significance data for
Table 3..................................... ....................
45
7. T-test significance data for
Table 4.........................................................
45
8. Vole capture and tissue metal concentrations data from the Swamp
Gulch study site.......................... .. . . ..............................................................
47
9. Vole capture and tissue metal concentrations data from the Hards­
crabble control site............................................
48
10. Shrew capture and metal concentration data..............................................
49
26
V ll
LIST OF FIGURES
Figure
Page
1. Location o f Lincoln, Montana, Swamp Gulch and Hardscrabble Creek. . .
2
2. Zinc concentrations in the wetland acrotelm...................................... .............
15
3. Swamp Gulch study site trap locations...............................................................
16
4. Daily trapping results (voles).................................................................................
24
5. Daily trapping results (sh r e w s).....................
25
viii
ABSTRACT
Concentrations of cadmium, copper, and zinc in the kidneys o f meadow voles
(Microtus pennsylvanicus) and in the whole bodies o f shrews (Sorex spp.) from an
acid mine drainage impacted wetland and a control wetland were determined.
Cadmium and copper levels were significantly elevated in kidneys of voles from the
contaminated wetland; zinc levels were not elevated. Shrew whole body cadmium
levels were also significantly higher while copper and zinc whole body levels were
not significantly different compared to animals from the control area. The elevated
levels o f cadmium demonstrate the potentially hazardous uptake of this element.
However, cadmium and copper levels were not considered to be accumulating to
hazardous levels in voles or shrews or to be a risk to animals that prey on them.
I
INTRODUCTION
Recently, artificial wetlands have become an alternative to conventional
chemical treatment of acid mine drainage (AM D).
The problems of degraded
water quality caused by A M D are widespread and have been very expensive to
ameliorate. In Montana, the use of man-made wetlands is being considered by the
Abandoned Mine Lands Bureau (AMLB) of the Department o f State Lands. An
earlier study (D ollhopf et al. 1988) concerning the AM D impacted Swamp Gulch
wetland suggested that these wetlands may pose a hazard to local wildlife.
Specifically, these wetlands act as accumulators of heavy metals, and the species of
wildlife living at high trophic levels may be subject to toxic levels of certain metals
through biomagnification.
A t the abandoned Carbonate Mine site near Lincoln, Montana (Figure I),
A M D has been entering into a natural wetland for over 40 years. The vegetation
in this wetland has been tested and found to have metal concentrations above levels
found in a nearby pristine wetland (Table I) (Dollhopf et al. 1988). The levels of
some metals are above maximum tolerable forage levels for cattle ingestion (Table
2) (National Academy of Science 1980). The 1988 study by D ollhopf suggested that
an examination o f metal levels in tissues of the common herbivores would help
determine the extent to which certain metals are present in the food chain.
Figure I. Location of Lincoln, Montana, Swamp Gulch and Hardscrabble Creek.
3
Table I. M etal concentrations (jug/g dry weight) in vegetation1 from the
study site (Swamp Gulch wetland) and the background site
(Hardscrabble Creek).
Hardscrabble Creek
n
mean
Element
Plant species
Cd
Salix boothii
Carex rostrata
Isopterygium pulchellum
2
4
I
0.6
0.8
0.7
Cu
Salix boothii
Carex rostrata
Isopterygium pulchellum
2 .
4
I
Zn
Salix boothii
Carex rostrata
Isopterygium pulchellum
2
4
T
Swamp Gulch
n
mean
6
5
4
5.6
1.5
7
0.35
3.8
15
6
5
4
1.3
62
132
130
96
44
6
5
4
388
134
1074
.
1 Aboveground tissue
Table 2. Maximum tolerable levels1 of dietary minerals for domestic
animals (National Academy o f Sciences 1980).
Element*
Cattle
Rabbit
Cd
Cu
Zn
0.5
100
500
(OJ)
200
(500)
1 All values are in jitg/g. Values in parentheses were derived by extra­
polation.
Other elements were analyzed and reported in Dollhopf et al. 1988.
4
The objectives of this study were to determine if metal levels in the
kidneys o f the herbivore M icrotm pennsylvanicus were higher in animals living in
the A M D impacted wetland as compared to levels in animals from a similar, but
visibly unimpacted wetland. If metal levels are higher, the second objective
would be to determine if these levels represent a threat to the voles themselves
or to the animals that prey on them. .
This research is limited by the funds available. It is not intended to be
the definitive statement about metal accumulation in animals frequenting
wetlands. It will, however, provide data about the uptake o f metals in such
areas and supply information for decision makers about the potential
accumulation of metals in wildlife in such areas.
5
LITERATURE REVIEW
Animals as Indicators o f Environmental Metal Crmfamjnation
A limited amount of information is available concerning the accumulation
o f heavy metals in wildlife inhabiting metal contaminated environments. We
have not been able to find work concerning metal accumulation in animals living
in wetlands impacted by acid mine drainage. However, studies have been done
involving the use of small mammals as indicators of possible bioaccumulation of
heavy metals from metalliferous mine sites (Roberts and Johnson 1978; Smith
and Rongstad 1982; Hunter et al. 1987; Andrews et al. 1984; Cloutier et al.
1986). V oles and mice have been used to show food chain accumulation of lead
along roadsides (Jeffries and French 1972; Mierau and Blaise 1975). Metal
accumulations have also been shown in wildlife living on land treated with
sewage sludge (Anderson et al. 1982; Dressier et al. 1986). Livestock and
wildlife living near smelters have also been shown to accumulate metals
(Munshower 1977; U S-EPA AP-91).
Few studies have been completed concerning the use o f small mammals
as indicators of environmental contamination. The use of the field vole (M.
agrestis) as an indicator o f heavy metal contamination in the environment was
shown to be the most sensitive indicator among three small mammals studied by
Beardsley et al. (1978). H e concluded, however, that differences in Microtus
6
tissue concentrations (whole body and liver) were too small to be considered
good indicators. Other work seems to refute this conclusion (Roberts and
Johnson 1978; Anderson et al. 1982; Andrews et al. 1984; Hunter et al. 1987).
In fact, a review by Martin and Coughtry (1982) of the Beardsley data, suggested
that differences in habitat metal concentrations actually were reflected in tissue
concentration levels of their animals.
Copper, Zinc and Cadmium Accumulation in Small Animals
The accumulation of metals by small mammals is not clearly understood.
Different species of small mammals accumulate metals at dissimilar rates.
Interactions between metals (synergistic, additive or antagonistic) affect uptake,
body distributions and also play a role in animal tissue metal concentrations.
Additionally, metal accumulation can be a function of sex or age (Anderson et
al. 1982; Smith and Rongstad 1982). Metals may be accumulated via the
digestive system from the diet or from the animal cleaning itself. Metals' may
also be absorbed by the respiratory system. All of these factors and others
influence animal tissue metal concentrations. The fact that individual species of small mammals accumulate metals at
differing rates is probably a result of differing diets or exposures among the
different species. Shrews, primarily insectivorous, have been shown to
accumulate cadmium at a higher rate than certain species of mice or voles,
I
primarily herbivorous (Roberts and Johnson 1978; Andrews et al. 1984; Hunter
et al. 1987). Hunter et al. (1987) showed that the shrew diet o f insects increased
cadmium intake 43 times from control site to contaminated site, while the
cadmium in the M icwtus diet increased only six fold. They concluded that the
shrews living at a higher trophic level were ingesting twelve times more cadmium
than the voles per day. Jeffries and French (1972) found different levels of lead
among three species of voles and mice living on roadside verges and attributed
this, in part, to differences in food consumed. In this study, M icwtus consumed
the most heavily contaminated material, grass, while Apodem us and Clethrionomys
consumed the seeds and kernels of many fruits discarding the husk and pulp
which were likely to have the highest lead concentrations. The wide ranging
forage behavior of Apodem us and Clethrionomys also allowed them to feed on
less contaminated material farther from the contamination source. Also, Smith
and Rongstad (1982) reported Pewmyscus accumulated lead at an active mine
site while M icw tus did not.
Elevated dietary or environmental levels of metals are not always reflected
by accumulation in small mammals. This is apparently due to the ability of
higher animals to metabolically regulate the retention o f some metals.
There is a lack of effective homeostatic control for cadmium in animals
(Underwood 1977) so it is not surprising that cadmium has been shown to
accumulate in tissues of small mammals living in environments o f elevated
8
cadmium concentrations. Andrews et al. (1984) reported elevated total body
cadmium levels in voles and shrews living on metalliferous mine waste. Smith
and Rongstad (1982) reported elevated cadmium levels in Microtus and
Peromyscus living on an active zinc-copper mine site. Other studies have shown
similar results on different types of metal contaminated sites: sewage sludge
treated fields (Anderson et al. 1982), smelter waste heaps (Johnson and Roberts
1978), and smelter fallout areas (Munshower 1977). Hunter et al. (1987)
reported some regulation of cadmium accumulation in Microtus at low levels of
exposure. Sorex living at the same site indicated no regulation at these levels.
In higher animals, the ability to regulate zinc retention has been well
documented (Vallee 1959). Studies concerning zinc retention in small mammals
have shown varying results. Roberts and Johnson (from two reports in 1978)
have shown that zinc was not accumulating in small animals living on mine sites
having elevated zinc concentrations. They attributed this to the possibility that
zinc is effectively regulated by these animals. Also, zinc concentrations in
meadow voles living in wheat and old field plant communities that received
applications of sewage sludge (high in zinc concentrations) were the same as
those found in animals from control sites (Andrews et al. 1982). However, Smith
and Rongstad (1982) showed a significant increase in zinc accumulation in
animals from mined sites compared to control sites. Zinc levels were found to
be higher in the femurs of cottontail rabbits living on sewage sludge treated
9
fields than in rabbits inhabiting non-treated fields (Dressier et al. 1986).
Significant differences were also found in kidneys of meadow voles fed sorghum
herbage containing 34 jig zinc/g and herbage containing 65.6 fig zinc/g (Williams
et al. 1978).
In all animals the continued ingestion of excess copper leads to some
accumulation in the tissues (Underwood 1977). Accumulation has been shown in
animals from environments containing high copper levels. Kidney and liver
copper concentrations were elevated in Microtus from sewage sludge treated
fields in Ohio (Anderson et al. 1982). Also total body concentrations of copper
were higher in Microtus and Peromyscus living at an active zinc-copper mine in
Ontario (Smith and Rongstad 1982). Again, however, other studies involving
environments high in copper indicated that some homeostatic control within
small mammals was occurring and copper was not accumulating. In Microtus,
Apodem us and Sorex studied from copper contaminated environments, total body
concentrations remained constant despite large scale increases in copper
ingestion (Hunter et al. 1987). As with zinc, this was attributed to efficiency of
homeostatic mechanisms controlling copper distribution in animals. Cloutier and
Clulow (1986) reported no kidney or liver variation in copper levels among
Microtus from mine tailings containing elevated levels of copper and animals
from a control site. In a similar study of Microtus pennsylvanicus from waste
water irrigated old fields and nonirrigated old fields, no variations were found in
10
the liver and kidney metal levels of voles from both sites (Anthony and
Kozlowski 1982). The variation in findings among these studies may reflect other
less well understood factors involved in the uptake of metals in animals.
The potential toxicity of certain metals is difficult to determine because of
the interactions that may occur if metals are available simultaneously. Cadmium
has been shown to decrease iron concentrations in tissues of Japanese quail (Fox
et al. 1971). Elevated dietary cadmium caused a zinc deficiency in poults
(Weber and Reid 1969). Marcus (1981) reported that a zinc treatment given to
male mice slowed the flow of calcium from blood to kidney. Underwood (1977)
also indicated that high amounts of zinc, copper and cobalt inhibited the uptake
of cadmium in animals.
Toxicities and Target Organs
Cadmium is selectively accumulated in various organs of higher animals.
Highest concentrations are found in the kidneys and liver, particularly the
kidneys (Flick et al. 1975; Underwood 1977); however, it is not restricted to
these organs (Flick et al. 1975). The presence of the metal binding protein
metallothionen in the kidneys and liver is responsible for the accumulation of
cadmium there. Similarly, in voles, highest concentrations of cadmium are found
in the kidneys (Johnson et al. 1978; Andrews et al. 1984). In M. agrestis living
on a metalliferous mine site, the kidneys contained 22.2% of the total body
11
burden of cadmium (Johnson and Roberts 1978). They also found that only the
liver and kidney cadmium levels differentiated between polluted and
uncontaminated environments. However, Andrews et ah .(1984) found significant
differences in muscle and bone tissue cadmium concentrations in animals from
mine and control sites.
Cadmium is toxic to every system in the animal body (Luckey and
Venugopal 1977). It also accumulates with age (Luckey and Venugopal 1977)
and has a long half life; approximately 30 years in man (Friberg et ah 1974) and
200 days in rats (Moore et ah 1973). The effects of cadmium toxicity are growth
retardation, impaired kidney function, poor reproductive capacity, hypertension,
tumor formation, hepatic dysfunctions, poor lactation and lowered hematocrit
levels (Luckey and Venugopal 1977). Minimum toxic levels or maximum dietary
cadmium levels cannot be given with precision because dietary intakes of other
elements with, which it interacts, notably zinc, copper, iron, and selenium
(Underwood 1977) obscure the precise statement of a chronic or toxic
concentration.
Low dietary cadmium levels do not seem to produce critical adverse
physiological effects. Levels of I to 10 jitg/g in the diet of mice had little or no
effect on digestion of dietary nutrients or on growth rates after three weeks
(Weber and Reid 1969). Concentrations of 412 ^g cadmium/g in the diet caused
a marked reduction in growth and 8% mortality. At levels of 2060 and 4120
12
Mg/g in the diet, mortality was 59% and 75% respectively after three weeks. Five
Hg cadmium/g in drinking water of mice increased kidney cadmium levels to 2.9-
6.4 jug/g and caused increased mortality at 21 to 24 months. No effect on
growth, mature weights or mortality were seen at 18 months (Schroeder et al.
1963). In studies reviewed by Doyle (1977), dietary cadmium levels of 0.1 to
10.0 produced hypertension in rats. However, similar studies reported by him
showed no induction of hypertension. In swine, no evidence of renal dysfunction
was noted until renal cadmium concentrations reached 200 jug/g wet weight
(Cousins et al. 1973).
Metal Movement Through Food Chains
Information concerning the uptake and distribution of metals through food
chains, particularly higher trophic levels, is limited. Again, there are several
factors that cause specific metals to be potentially mobile or nonmobile through
x
these trophic levels. Some of these include homeostatic control mechanisms,
target organs of accumulation, and dietary habits and feeding ranges. Cadmium
is considered to be highly mobile in food chains (Hunter et al. 1987; Smith and
Rongstad 1982) due to the lack of homeostatic control of cadmium in animals,
and the fact that cadmium accumulates primarily in the soft tissues. Zinc and
copper are less likely to be mobile in food chains due to homeostatic control
mechanisms that regulate the retention of these metals. Ingested lead is also
13
unlikely to move through food chains because a large part of it is immobilized in
skeletal tissue (Johnson and Roberts 1978). Skeletally incorporated lead is
relatively unavailable for intestinal absorption (Roberts and Johnson 1978).
14
MATERIALS A N D M ETHODS
Selection of an Indicator Species
Microtus pennsylvanicus was chosen as an indicator species for this study
because of their abundance and distribution at the Swamp Gulch site (Dollhopf
et al. 1988) and they m eet criteria for small mammal indicators as presented by
Beardsley et al. (1978). These authors indicated that the ideal biological
indicator should be small arid easily caught, have a territory o f limited range, an
unselective but herbivorous diet, and a short life span so that individuals could
be assumed to be fairly closely adjusted to their environments. The natural
history of M. pennsylvanicus matches these criteria very closely.
Selection of Trapping Area
Within the Swamp Gulch wetland, trapping was done in areas of greatest
predicted cadmium accumulation. The D ollhopf et al. (1988) study of these
wetlands did not map specific areas of cadmium accumulation in the upper,
undecom posed organic matter layer (acrotelm). However, zinc contamiriation
was mapped and because of its naturally close association with cadmium
(Hammons et al. 1978) this map was used to delineate areas where voles would
be trapped (Figure 2). Within the 3.9 ha o f AM D impacted wetland, the zone
o f zinc accumulation greater than 3000 mg/1 in the wetland acrotelm was chosen
15
Figure 2. Zinc concentrations in the wetland acrotelm (D ollhopf et al. 1988).
as the trapping area. Traps were placed within the boundaries of this area of
approximately 2500 m2 (Figure 3). This did not include the entire area
delineated by 3000 mg/1 zinc accumulation due to part of the area being
submerged and therefore unable to support voles. After nine days, trapping was
terminated due to the low numbers of voles being taken and because enough
animals had been taken for a competent statistical comparison.
Montana pnn
LEGEND
Trapping site number- 21
Zinc isoline (mg/kg)
--------- 4 0 0 0 — -
Carex rest rata
Shrubs & Carex
Open water
Scale
m eters
Figure 3. Swamp Gulch study site trap locations.
17
A similar wetland, unimpacted by acid mine drainage located on nearby.
Hardscrabble Creek, was used as a control site. Here traps were placed in the
only area of similar vegetation (Carex rostrata dominated) which also happened
to be similar in size to the Swamp Gulch study site.
Trapping
Animals were trapped from the study site and the control site using snap
traps placed in runways and places exhibiting other signs o f recent Microtus
activity. Approximately 75 traps were used in each of the two sites and traps
were set and baited daily with chewy granola. The traps on the Swamp Gulch
and Hardscrabble Creek sites were checked and reset daily from August 5
through August 13, 1988. All trapped animals were placed individually in plastic
bags, numbered, and taken to the Reclamation Research Laboratory at
Montana State University, weighed and frozen.
Twenty-five voles were trapped from the Swamp Gulch study site and 14
were trapped from the Hardscrabble Creek control site. Eight shrews were
incidentally trapped from each of these sites.
Laboratory Analyses
Kidney tissues were taken from the voles during necropsy and weighed in
very clean 125 ml erlenmeyer flasks. Fifty milliliters of concentrated H N 0 3 were
18
then added to the flasks. The tissues were allowed to digest overnight unheated
with parafilm covers. The next day, flasks were placed on a 100 ° C hotplate and
digested all day. Approximately six hours later, 3 ml of 30% H2O2 was placed in
each flask. They were then placed on the hotplate again at 100 ° C and allowed
to react until relatively clear. Digestions were then taken off the. hot plate,
cooled, and transferred to 50 ml volumetric flasks for analysis. Shrews were
digested the same way except 125 ml erlenmeyer flasks and 15 ml concentrated
H N O 3 were used. After digesting, samples were transferred to 100 ml volumetric
flasks.
V ole kidneys and shrew whole bodies were analyzed for zinc and copper
by flame A A analysis and cadmium by graphite furnace A A analysis. Vole
kidney tissues from Swamp Gulch were analyzed for nickel, manganese and lead.
However, because the metal levels in the kidney tissues were below detection
limits, analyses for these metals was discontinued.
Accuracy of the determinations was based on spike recoveries of analytes
added prior to digestion and recoveries of National Institute o f Standards and
Technology (NIST) bovine liver standard. For vole kidney samples, spike
recoveries for cadmium, copper, and zinc were 94.0%, 87.7%, and 104.5%
respectively. Bovine liver standard recoveries were 199.0%, 97.5%, and 109.0%
respectively. For shrew whole body samples, spike recoveries were 76.6% (Cd),
101.0% (Cu), and 103.0% (Zn). Bovine liver standard recoveries were 147.7%
(Cd), 58.7% (Cu), and 89.4% (Zn).
19
Statistical Methods
Students t-test was used to determine whether significant differences were
present between control and study site mean tissue metal levels.
20
DESCRIPTION OF ST U D Y A R E A
General Location
The Swamp Gulch Wetland study site is located 22.4 km east of the town
of Lincoln, Montana in Lewis and Clark County (Section 20, TIN , R6W) (Figure
I). The site is bordered on the north by Montana Highway 200 and on the
south by the Blackfoot River. The entire wetland covers approximately 72.9 ha,
of which 3.9 ha are apparently impacted by AM D.
Natural Environment
The wetland study site is in the headwaters of the Blackfoot River at an
elevation o f about 1573 m. Elevations in the Swamp Gulch drainage which flows
into a portion of the study area range from about 1574 m to 1908 m . The
Swamp Gulch watershed contains 72.6 ha and is composed o f generally well
vegetated southeast to southwest aspects with a total length o f about 1.6 km .
The site is on the west side of the continental divide and is therefore influenced
more by pacific weather patterns than by the continental climate in the region
east o f the divide. However, moisture from the Gulf of M exico occasionally
spills over the divide during the summer producing intense thunderstorms. Mean
annual precipitation is approximately 73.7 cm (SCS 1981) much o f which occurs
as snow (Coffin and Wilke 1971).
21
The Blackfoot River drainage was significantly influenced by glaciation.
Sediments deposited by retreating valley glaciers created a series of moraines and
outwash plains in the Lincoln area allowing for the formation of wetlands in
drainage impeded areas on the upslope sides o f the moraines (Alt and Hyndman
1972). The lithology of the study area is dominated by the Spokane Shale
Formation, part o f the Belt series super group. This formation consists of red or
red-purple shale with numerous green beds locally with quartzite (Ross et al.
1955). Parent material of the valley floor apparently consists o f a thin layer of
glacial till with fluvial gravel deposits.
Carbonate Mine History and Geology
Swamp Gulch and many other drainages of the region have been
impacted by mining. The Carbonate Mine is within the Heddleston mining
district and in 1933 included an adit about 850 feet long and a shaft
approximately 300 feet deep (Pardee and Shrader 1933). A 75 ton mill was
erected in the summer o f 1944 and it is reported that 2500 tons o f lead-zinc ore
were taken out in 1945 (Shea 1947).
The geology of the Carbonate Mine is similar to that o f the Mike Horse
Mine which is the largest mine in the district (Shea 1947). The mine workings
are in a diorite sill that intruded argillite o f the Spokane Formation, Belt
Precambrian sedimentary rocks (McClernan 1983). Intruding into the sill and
22
Belt rocks is a decomposed rhyolite dike (Shea 1947). Pardee and Schrader
(1933) describe the lode as consisting of a sheared and altered diorite partly
- replaced by sulfides. The mine lode contains abundant pyrite in several forms
including fine grained, coarse grained, and radial. Ore minerals are galena,
sphalerite, silver and gold. Gangue minerals occur primarily as sericite, pyrite
and quartz and also include "a carbonate containing calcium, iron and a little
manganese" (Pardee and Schrader 1933).
The dominant soil in the study area is a Hydric Borofibrist (Soil Survey
Staff 1975). The gravels most often encountered at depth are fluvial in origin as
evidenced by many subrounded pebbles. These were deposited by the
meandering river following glaciation and were likely derived from glacial
outwash materials.
Vegetation on Study Sites
,
Vegetation within the Swamp Gulch wetland is dominated by the sedge
(Carex rostrata). This species is sometimes associated with marsh birch (Betula
glandulosa), Booth willow (Salix boothii) or lodgepole pine (Pinus contorta), but
is most often encountered in nearly pure stands. Where the water table is
relatively low, plant species more indicative o f the surrounding forest are found.
The composition of vegetation at the Hardscrabble Creek site was very
similar to the Swamp Gulch wetland site. Carex rostrata dominated with about
23
60 percent canopy coverage and Salix Boothii and Betula glandulosa were the
dominant shrubs. Herbaceous production at the background site was not
measured but did not appear to be significantly different from production on the
Swamp Gulch site.
Collection Sites
Trapping took place in the Swamp Gulch wetland approximately 100 m
west of the culvert that drains Swamp Gulch and 15 to 45 m south of Montana
Highway 200 in a mostly open area dominated almost exclusively by Carex
rostrata. The specific boundaries of the trapping area were delineated by the
3000 jig/g isolines of zinc accumulation in the acrotelm (Figure 2). Trapping was
limited to the northern two thirds of this area where the soil surface was not
submerged.
A t the Hardscrabble Creek site, trapping was conducted mostly in the
western half of the wetland where there were open stands o f Carex rostrata
similar to those in the Swamp Gulch site.
24
RESULTS
Trapping Success
A total of 25 Microtiis pennsyIvanicus were trapped within the 0.25 ha
study area during the nine day study period (Figure 4). During the same period,
eight shrews were also caught in the traps (Figure 5). The number of animals
trapped per day grew until a peak of seven per day was reached on August 10.
After that date, the numbers declined until trapping was terminated.
Eighteen Microtus were caught from within the control area during the
same period animals were trapped from the Swamp Gulch wetland. Numbers of
Microtus trapped peaked after three days at five animals and declined until
trapping ceased. Four voles were found mostly consumed and not adequate for
analysis.
Number caught=
e
Date caught= Aug.
Gray bar - Study site vole(s)
Solid bar - Control site voleCs)
Blank bar - Vole caught/destroyed by scavenging fauna
Figure 4. Daily trapping results (voles).
25
Figure 5. Daily trapping results (shrews)
Metal Levels
Levels of copper, zinc, and cadmium were determined for vole kidney
tissues and shrew whole bodies (Table 3). Nickel, lead, and manganese levels
were also analyzed in these tissues but concentrations were below detection limits
of 5, 8, and 13 jitg/g respectively. Analyses for these three elements were not
performed on the control site animals (Table 4).
In general, metal levels were significantly higher in the animal tissues from
the Swamp Gulch wetland as compared to the control site. Levels of cadmium
and copper were significantly higher in vole kidneys from the Swamp Gulch
wetland than those from the control site. However, zinc concentrations were
significantly higher in vole kidneys from the control site. Shrew whole body
cadmium concentrations were also significantly higher in the study site animals.
Copper and zinc levels in shrew whole bodies were not significantly different
between animals from the two sites.
26
Table 3. Metal concentrations (/xg/g wet weight) in M. pennsylvanicus kidney
tissues.
Site
n
Cd
mean +.
std. error
n
Cu
mean +_
std. error
Swamp Gulch
Wetland
24
2.2+0.5 a1
25
Control
14
0.3+0.1 b
13 , 4.8+0.8 b .
6.1+0.3 a
n
Zn
mean ±_
std. error
25
28.4+1.7 a
14
36.2+3.9 b
1 Means within a given elem ent followed by the same letter are not
significant at the 5% level by t-test.
Table 4. Metal concentrations Qug/g wet weight) in whole body Sorex spp.
Site
n
Cd
mean ±_
std. error
Swamp Gulch
Wetland
8
0.3+0.10 a1
8
6.4±1.6 a
8
30.6+2.9 a
Control
8
0.1+0.03 b
7
4.9+0.9 a
8
31.7+1.7 a
n
Cu
mean +.
std. error
n
Zn
mean _+
std. error
1 Means within a given elem ent followed by the same letter are not
significant at the 5% level by t-test.
27
A comparison o f kidney metal levels within the Swamp Gulch study site
indicated that voles trapped from the area of greater than 4000 mg/kg zinc in
the wetland acrotelm were not accumulating greater amounts o f cadmium or zinc
than animals trapped from the area of less than 4000 mg/kg zinc (Table 5).
Apparently tissue metal levels within the study site are comparable.1
Table 5. Metal concentrations (/xg/g wet weight) in M. pennsylvanicus kidney
tissues within the Swamp Gulch wetland.
-
Cd
mean ±
n . std. error
n
Zn
mean ±
std. error
Less than 4000 mg/kg
zinc in acrotelm
14
2.2+0.4 a'
14
28.2±0.9 a
Greater than 4000 mg/kg
zinc in acrotelm
11
2.3±0.4 a
11
28.7±1.5 a
V ole Trapping Area
1 Means within a given element followed by the same letter are not significant
at the 5% level by. t-test.
28
DISCUSSION
Microtus Densities
It is believed that the numbers of voles trapped were representative of the
populations of the two trapping sites. Trapping was not done in a manner which
is considered to be indicative of population densities so accurate estimates
cannot be made as to the natural density of the animals in the area studied.
However, because trapping success declined to almost zero after nine days at
both sites, it was assumed that a large part of the population was captured. If
all Microtus were trapped from the 0.25 ha Swamp Gulch study area, it would
represent a density o f 100 voles/ha. This would coincide with densities of 95 and
80 voles/ha living in a Minnesota wetland reported by Bim ey et al. (1976).
These were peak animal densities (low densities were reported as 10 voles/ha).
Far greater and lesser densities have been reported at other types of sites (Taitt
and Krebbs 1985). Taitt and Krebbs report average maximum and minimum
densities o f 172/ha and 57/ha for annual fluctuations of Af. pennsylvanicus
populations across North America. Also, because the study site was naturally
bordered by habitat unsuitable for Microtus habitation (submerged vegetation,
tree and shrub cover), it is unlikely that many animals migrated into this site and
were captured.
29
Tissue Metal Concentrations
Cadmium levels reported by D ollhopf et al. (1988) for above ground
tissues o f Carex rostrata were 1.9 /ig/g oven dry tissue. These levels are higher
than the maximum dietary plant intake standard for livestock consumption
presented by the National Academy of Sciences (1980) of 0.5 jug/g. These levels
reflect the natural accumulation of cadmium at the Swamp Gulch study site from
AM D. They also represent a possible threat to wildlife living in this
environment through biomagnification. Cadmium is known to be highly mobile
in food chains (Roberts and Johnson 1978, Hunter et al. 1987, Anderson et al.
1982). The mean cadmium level measured in the kidneys of M pennsylvanicus
from the Swamp Gulch wetland site is significantly higher than the cadmium
levels measured in Microtus kidneys from the control site. These results are
similar to other studies (Johnson and Roberts, Andrews et al. 1984, Anderson et
al. 1982). The mean cadmium kidney concentration in animals from the Swamp
Gulch wetland is also comparable to wet weight levels reported by Anderson et
al. (1982) for voles living on sewage sludge treated fields. The mean cadmium
concentration levels in the Carex also correspond very closely to concentrations in
plant tissue produced on sewage sludge treated soils (Williams et al. 1978).
Similarly, the levels found in Swamp Gulch Microtus kidneys correspond to the
levels found in kidneys o f Microtus from the sewage sludge contaminated site as
reported by in the Williams study. The higher cadmium levels found in voles in
30
the Swamp Gulch wetland reflect (as compared to the control site) the inability
of animals to control cadmium retention. The higher levels in voles also
represent a pathway of accumulation into the local food chain.
Hazard to Microtus
Microtus are herbivores that consume mostly vegetative plant parts. The
actual composition of plant species in their, diet is reflected by the abundance of
those species of plants in the local habitat (Zimmerman 1965). Because Carex
rostrata is the dominant plant species, found in pure stands at the Swamp Gulch
wetland, it is likely that the voles are using this plant as their primary food
source.
By comparing cadmium levels found in the Carex at the Swamp Gulch
wetland with toxicity data, potential hazard to the Microtus may be assessed.
The levels of cadmium found in the Carex are lower than levels that have caused
tissue damage or mortality in animals fed cadmium containing diets in laboratory
)
experiments (W eber and Reid 1969, Cousins et al. 1973, Doyle et al. 1974,
Richardson et al. 1974); although minor physiological effects such as hypertension
and slight decreases in survival have been reported in mice and rats fed low
levels o f dietary cadmium (Schroeder and Vinton 1962, Schroeder et al. 1963,
Perry and Erlander 1974). Also, observable toxicological effects have not been
reported in laboratory animals fed herbage grown on cadmium-containing sewage
31
sludge (Furr et al. 1976, Hansen et al. 1976). Furthermore, the high turnover
rate o f voles, which has been reported by Getz (1980) to have an average
lifespan of less than one month, does not allow long term cadmium accumulation
which might produce tissue damage or mortality. Although there may be some
minor, physiological effects felt by the vole population in the Swamp Gulch
wetland, major pathology is not indicated. The existence of an apparently
normal functioning population seems to support this conclusion.
Possible Hazard to Higher Trophic Levels
Wildlife that might be at risk from cadmium accumulation are those
species that feed in the contaminated area (3.9 ha) of the Swamp Gulch wetland.
The species affected would be those that make the AM D impacted area the
major portion of, if not their entire feeding range. Predators at risk are those
that include voles as a large part of their diet. Two species that might represent
a worst-case cadmium accumulation are the least weasel (Mustela rixosd) and the
great grey owl (Strix nebulosa).
The weasel is known to prefer Microtus in its diet and their feeding
territories may cover as little as 3.5 ha (Fitzgerald 1977). It is possible that in
the worst-case scenario a weasel would be feeding entirely upon A M D impacted
Microtus. The total Microtus body burden of cadmium, therefore, becomes
important.
32
The wet weight kidney cadmium concentration of Microtus from the
impacted wetland was 2.2 ng/g. The mean weight of the two kidneys from these
Microtus was 0.3 g. The total kidney cadmium burden can be calculated:
2.2 Atg/g x 0.3g = 0.66 Atg/kidney tissue
Since the Microtus kidney contains 22.2% of the total body cadmium burden
(Roberts & Johnson 1978) whole body cadmium burden may be calculated as:
(100 -7- 22.2) x 0.66 jug/g = total body burden = 3.0 ^gIMicrotus.
The average wet weight of a Microtus was 20.8 g. The concentration of
cadmium in the Microtus from the Swamp Gulch wetland was:
3.0 jug T 20.8 g = 0.14 ng/g wet weight.
This can be converted to a dry weight. The mean water content of Microtus has
been reported as 66.7% (33.3% dry matter content)(Jeffries and French 1972):
(100 4- 33.3) x 0.14 Atg/g wet weight = .42 jug/g dry weight.
Since the major portion o f the cadmium is located in the soft tissues, it is likely
that most of this would be available for absorption by the weasel.
Little is known concerning dietary cadmium effects in carnivores, however,
in swine, levels o f 200 /ig/g in the diet were required to produce noticeable signs
33
o f toxicity (Cousins 1982). Male mice fed drinking, water containing 5 ng
cadmium/ml suffered significantly greater mortality later in life (Shroeder et al.
1963). It appears that chronic exposure to cadmium may produce pathologic
effects, however, the extent o f these cannot be clearly determined for weasels.
In birds of prey, the great grey owl is a good example for worst case
effects o f cadmium accumulation. It has been shown to have a diet consisting
almost entirely of Microtus (Brunton and Pittany 1973) and to have a small
feeding territory (40 ha) (Brunton and Pittany 1973) as compared to most birds
o f prey. One can see that in this owl’s feeding territory the A M D contaminated
zone makes up a very small percentage of available food. If it were
hypothesized that an owl was consuming Microtus with a dietary level of 0.42 /zg
cadmium/g dry weight for extended periods o f time, there is little probability of a
deleterious effect. Mallard ducks fed cadmium at rates of 2 and 20 jzg/g
accumulated 2.9 and 45.8 /zg cadmium/g wet weight in the kidney respectively
(White and Finley 1978). In this same study, dietary cadmium did not cause
significant body weight loss or decreased food consumption. However, 200 /zg/g
in the diet caused a significant decrease in egg production. Twelve /zg
cadmium/g in the diet o f chickens was shown to cause a decrease in egg
production (Leach et al. 1979). Even if the dietary levels in the Swamp Gulch
wetland voles were higher, that is nearer to levels that have produced pathologic
effects in other types of fowl, the wide feeding range of most raptors would
34
cause areas the size o f the Swamp Gulch wetland AM D impact area to
constitute a very small percentage of a raptor’s foraging area. Larger areas of
contamination, those that might compose the entire feeding range o f a particular
bird, might present a risk to its health.
Metals that may have accumulated on the fur of the voles were not
measured in this study. Through the voles’ natural habit of cleaning themselves,
some of the metals in the fur would be ingested and therefore represented in the
tissue burden. However, the metals that may be present on the fur at the time
o f capture could represent a greater cadmium intake to the predator.
Shrews are not considered common prey for predators (Andrews et al.
1984) and so further food chain movement o f cadmium would be limited with
regard to these animals.
35
SUM M ARY A N D CONCLUSIONS
In Montana, the use of artificial wetlands is being considered as an
alternative in the treatment of acid mine drainage. These wetlands act as
natural filters in removing heavy metals from acidic mine waters draining into
them. The substrate and vegetation accumulate these metals to levels, which in
some cases, are many times higher than natural background concentrations.
These high levels represent a possible hazard to wildlife inhabiting these
wetlands.
To determine this risk, metal concentrations in voles (Microtus
pennsylvanicus) from an acid mine drainage-impacted wetland (Swamp Gulch)
were assessed. The kidneys of these voles were analyzed for cadmium, zinc, and .
copper. The kidney tissues were analyzed because this organ has been shown to
accumulate the highest concentrations of cadmium in small mammals.
Significantly higher levels of cadmium and copper were found in the kidneys of
the animals from the study site. These results are comparable to results
obtained in other similar studies. Even though cadmium risk levels are higher in
the study site animals, they do not appear to represent a health risk to the
Microtus population. The amount of cadmium found in the Microtus whole body
are probably too low to represent a threat to any wildlife that might be feeding
upon them.
36
The size o f the contaminated area represents a small percentage of the
feeding range of most predatory mammals or birds that might include these voles
as part or all .of their diet. This further reduces the risk o f poisoning or
adversely affecting the reproduction of these predators. Very little is known
about the movement of heavy metals such as cadmium through higher trophic
levels, and more work is needed in this area to determine the specific effects
these levels o f metals in prey species may have upon the predators that consume
them. This study was not intended to fill all o f these voids in our knowledge of
food chain metal accumulation. It has, however, given us data that support the
conclusions expressed in this report.
37
LITERATURE CITED
38
Alt, D .D . and D.W. Hyndman. 1972. Roadside Geology of the Northern
Rockies. Mountain Press Pub. Co., Missoula, MT. 280 p.
Anderson, T.J., G.W. Barrett, C.S. Clark, V.D. Elia and V.A. Majeri. 1982.
M etal concentrations in tissues of meadow voles from sewage-sludgetreated fields. J. Env. Qual. 11(2):272-277.
Andrews, S.M., M.S. Johnson and J.A. Cooke. 1984. Cadmium in small
mammals from grassland established on metalliferous mine waste. Env.
Poll. (Series A ) 33:153-162.
Anthony, R.G., J.R. Kozlowski. 1982. Heavy metals in tissues o f small
mammals inhabiting waste-water-irrigated habitats. J. Env. Qual.
ll(l):2 0 -2 2 .
Beardsley, A., M J. Vagg, P.H.T. Beckett and B.F. Sansom. 1978. U se of the
field vole (Microtus agrestis) for monitoring potentially harmful elements in
the environment. Env. Poll. 16:65-69.
Birney, E.C., W.E. Grant and D.D. Baird. 1976. Importance of vegetative cover
to cycles o l Microtus populations. Ecology 57:1043-1051.
Brunton, D.F. and R. Pittany, Jr. 1971. Observations of the Great Grey Owl on
winter range. The Canadian Field-Naturalist 85:315-321.
Cloutier, N.R., F.V. Clulow, T.P. Lim and N.K. Dave. 1986. Metal (Cu, Ni, Fe,
Co, Zn, Pb) and Ra-226 levels in tissues of meadow voles Microtus
pennsylvanicus living on nickel and uranium mine tailings in Ontario
Canada: site, sex, age and season effects with calculation of average
skeletal radiation dose. Env. Poll. (Series A) 41:295-314.
Coffin, D.L. and K.R. Wilke. 1971. Water resources of the upper Blackfoot
River Valley, west central Montana. Dept, of Nat. Resources and
Conservation: Technical Report Series of Water Resources Division,
No. I.
Cousins, R.J., A.K. Barbor and J.R. Trout.. 1973. Cadmium toxicity in growing
swine. J. Nutr. 103:964-972.
39
Dollhopf, D.J., J.D. Goering, R.B. Rennick, R.B. Morton (MSU); W.K. Gauger,
J.B. Guckert, P.M. Jones, K.C. Cooksey, K.E. BuckJin, R. Weed, M.M.
Lehman (M D I). 1988. Hydrogeochemical, vegetational and
microbiological effects of a natural and constructed wetland on the control
of acid mine drainage. Reclamation Research Unit, Montana State Univ.,
Bozeman, MT. 214 p.
Doyle, J.J., W.H. Pfander, S.E. Grebing and J.O. Pierce, IL 1974. Effect of
dietary cadmium on growth, cadmium adsorption, and cadmium tissue
levels in growing lambs. J. Nutr. 104:160-166.
Doyle, J.J. 1977. Effects of low levels of dietary cadmium in animals - a review..
J. Env. Qual. 6(2): 111-116.
Dressier, R.L., G.L. Storm, W.M. Tzilkowski and W.E. Sopper. 1986. Heavy
metals in cottontail rabbits on mined lands treated with sewage sludge. J.
Env. Qual. 15(3):278-281.
Fitzgerald, B.M. 1977. Weasel predation of a cyclic population of the Montana
vole (Microtus montanus) in California. J. Anim. Ecol. 46:367-397.
Flick, D.F., H.J. Kraybull and J.M. Dimitroff. 1975. Toxic effects of cadmium:
a review. Env. Research 4:71-85.
Fox, M.R.S., B.E. Fry Jr., B.F. Harland, M.E. Schertel and C.E. Weeks. 1971.
Effect of ascorbic acid on cadmium toxicity in the young coternix. J.
Nutrition 101:1295-1306.
Friberg, L., N. Piscator, G.F. Nordberg and T. Kjellstrom. 1974. Cadmium in
the Environment 2nd Edition, CRC Press Inc., Cleveland, OH.
Furr, A.K., G.S. Stoews, C A . Bachle and D.J. Lisk. 1976. Study of guinea pigs
fed swiss chard grown on municipal sludge-amended soil: multi element
content of tissues. Arch. Env. Health 31:87-91.
Getz, L.L. 1960. A population study of the vole, Microtus pennsylvanicus.
Amer. Mid. Nat. 64:392-405.
Hammons, A S ., J.E. Huff, H.M. Braunstein, J.A. Drury, C.R. Shriner, E.B.
Lewis, B.L. Whitfield and L.E. Towill. 1978. Reviews of the
environmental effects of pollutants: IV. Cadmium. U.S.E.P.A. Report
No. EPA-600/1-78-026; ORNL/EIS-106. Cincinnati, Oh. 251 pp.
40
Hansen, L.G., J.L. Dorner, C S. Byerly, R.P. Tarara and T.D. Hinesly. 1976.
Effects of sewage sludge-fertilized corn fed to growing swine. Amer. J.
Vet. Res. 37:711-714.
Hunter, B A ., M.S. Johnson and D.J. Thompson. 1987. Toxicology of copper
and cadmium in a contaminated grassland ecosystem. J. App. Eco.
24:601-614.
Jeffries, D.J. and M.C. French. 1972. Lead concentrations in small mammals
trapped on roadside verges and field sites. Env. Poll. 3:147-156.
Johnson, M.S., and R.D. Roberts. 1978. Distribution of lead, zinc and cadmium
in small mammals from polluted environments. Oikos 30:153-159.
Leach, Jr., R.M., K.W. Wang and D.E. Baker. 1979. Cadmium and the food
chain: The effect of dietary cadmium on tissue composition in chicks and
laying hens. J. Nutr. 109:437-443.
Luckey, T.D. and B. Venugopal. 1977. Metal Toxicity in Mammals. Volume I.
Plenum press, N Y and London.
Marcus, H.M. 1982. Multicompartment kinetic models for cadmium. I. Effects
of zinc on cadmium retention in male mice. Env. Research 27:46-51.
Martin, M.H. and P.J. Coughtrey. 1982. Biological Monitoring of Heavy Metal
Pollution. Copyright Applied Science Publishers, Ltd.
McClernan, H.G. 1983. Metallic Mineral Deposits of Lewis and Clark County,
Montana. Memoir 52, Montana Bureau of Mines and Geology. 73 p.
Mierau, G.W. and Blaise, E.F. 1975. Lead poisoning in roadside populations of
deer mice. Env. Poll. 8:55-64.
M oore, W., J.F. Stava, W.C. Crocker, M. Malanchule and R. litis. 1973.
Comparison of cadmium retention in rats following different rates of
administration. Env. Research 6:473.
Munshower, F.F. 1977. Cadmium accumulation in plants and animals of
polluted and nonpqlluted grasslands. J. Env. Qual. 6(4):411-413.
National Academy of Sciences. 1980. Mineral tolerances of domestic animals.
National Academy of Engineering. U.S. Government Printing Office.
Washington, D.C.
41
Pardee, J.T. and F.C. Schrader. 1933. Metalliferous deposits o f the greater
H elena Mining District. U.S. Geol. Survey, Bulletin 842. U.S.
Government Printing Office, Washington, D.C.
Perry, M., Jr. and M. Erlander. 1974. Hypertension following the chronic
feeding o f low doses of cadmium and mercury. J. Lab. Clin. Med. 32:510.
Richardson, M.E., M.R. Spivey Fox and B.E. Fry, Jr. 1974. Pathological
changes produced in Japanese quail by injection of cadmium. J. Nutr.
104:323-338.
Roberts, R.D. and M.S. Johnson. 1978. Dispersal of heavy metals from
abandoned mine workings and their transference through terrestrial food
chains. Env. Poll. 16:293-310.
Ross, C.P., D.A. Andrews and I.J. Witkind. 1955. Geologic map of Montana.
Montana Bureau of Mines and Geology.
Schroeder, H.A. and W.H. Vinton, Jr. 1962. Hypertension induced in rats by
small doses of cadmium. Amer. J. Physiol. 202:515-518.
Schroeder, H.A., W.H. Vinton, Jr. and J.J. Balassa. 1963. Effect of chromium,
cadmium and other trace metals of the growth and survival of mice. J.
Nutr. 80:39-47.
)—
'
Shea, T.K. 1947. Geology and Mines of the Upper Blackfoot Valley, Montana.
B.S. Thesis, Department of Geology, Montana School of Mines, Butte,
Montana. 24 p.
Smith, G.J. and O.J. Rongstad. Small mammal heavy metal concentrations from
mined and control sites. Env. Poll. (Series A) 28:121-134.
Snedecor, G.W. and W.G. Cochran. 1980. 7th Edition. Statistical Methods.
Iowa State Univ. Press, Ames, IA.
Soil Conservation Service (SCS). 1981. Average Annual Precipitation, Montana.
U.S. Department of Agriculture, Bozeman, Montana.
Soil Survey Staff. 1975. Soil Taxonomy: A basic system of soil classification for
making and interpreting soil surveys. Agriculture Handbook No. 436. U.S.
Dept, of Agriculture. U.S. Government Printing Office, Washington, D.C.
42
Taitt, M.J. and C.J. Krebbs. 1985. Microtus IN: Biology of new World. R.H.
Tamarin (ed.). The American Society of Mammalogists, Special Pub. No.
8 pp. 567-619.
Underwood, E.J. 1977. Trace elements in Human and Animal Nutrition. 4th
Edition. Academic Press, New York.
U.S. Environmental Protection Agency. 1972. Helena Valley, Montana, Area
Environmental Pollution Study. U.S. EPA Office of Air Prog. Publ. No.
AP-91.
Vallee, B.L. 1959. Biochemistry, physiology and pathology of zinc. Physio. Rev.
39:443-90.
Weber, C.W. and B.L. Reid. 1969. Effect of dietary cadmium on mice.
Toxicology and Applied Pharmacology 14:420-425.
White, D.H. and M.T. Finley. 1978. Uptake and retention o f dietary cadmium
in mallard ducks. Env. Research 17:53-59.
Williams, P.H., J.S. Shenk and D.E. Baker. 1978. Cadmium accumulation by
meadow voles from crops grown on sludge-treated soil. J. Env. Qual.
7(3):450-453.
Zimmerman, E.G. 1965. A comparison of habitat and food of two species of
. Microtus. J. Mamm. 46:605-612.
43
APPENDICES
44
APPENDIX A
Statistical Data
45
Table 6. T-test* significance data for Table 3.
Element
0 .0 0 0
8
0 .0 0 0
I
Differences in Means
T - value
P - value
1-3 jUgZg
3.47
O
O
Element
1.9 jugZg
7.134
OO 0\
K ro
Differences in Means
T - value
P - value
Microtus Kidnev Tissue
Cd
Cu
Zn
Shrew Whole Bodv
Cd
Cu
Zn
0.24 jUgZg
3.92
0 .0 0 0
1-5 MgZg
1.92
0.0767
1.1 MgZg
-0.72
0.4834
* Where group variances were unequal, the quantity t= (x i x2)/ S12Zn1 + S22Zn2
replaces the ordinary t and degrees of freedom were assigned by
Satterthwaites approximation (Snedecor and Cochran 1980).
Table 7. T-test significance data for Table 4.
Element
Differences in Means
T - value
P - value
Cd
Zn
0.1 ju-gZg -0.5 /^gZg
0.513
-0311
0.613
0.757
46
APPENDIX B
Data Tables
47
Table 8. V ole capture and tissue metal concentrations data from the Swamp
Gulch study site.
Vole Number
Capture Data
Trap Site Number
Date Captured
Kidnev Metal Concentration f«g/g wet weight) Data
Cadmium
Copper
Zinc
I
2
12
49
08-07-88
0.47
3.63
6.1
7.0
32.9
40.6
3
4
5
18
29
7
08-08-88
2.47
3.10
0.79
5.0
5.2
5.1
29.9
Z18
26.6
6
7
8
9
15
67
47 69
08-09-88
1.70
3.31
3.53
4.53
6.2
5.2
6.6
5.9
29.5
30.2
31.7
23.7
10
11
12
13
14
15
16
3
62
11
20
26
21
7
08-10-88
0.69
2.10
4.55
0.70
4.42
1.42
1.61
5.9
6.7
6.8
5.8
6.2
5.5
5.6
23.7
29.5
25.4
30.2
26.0
25.2
25.2
17
18
19
20
21
5
23
3
42
75
08-11-88
NA*
1.09
0.86
2.73
1.17
7.8
7.0
6.2
&3
5.9
32.6
34.8
22.5
25.0
24.7
22
23
24
46
61
69
08-12-88
1.75
1.81
2.68
4.9
5.5
6.7
28.1
29.4
29.5
25
72
08-13-88
1.82
7.3
25.0
* NA = Not analyzed.
"
48
Table 9. Vole capture and tissue metal concentrations data from the
Hardscrabble Creek control site.
Vole Number
Capture Data
Trap Site Number
Date Captured
Kidnev Metal Concentration (u e J z wet weight) Data
Cadmium
Copper
Zinc
I
2
3
4
15
26
32
29
08-07-88
0.16
0.22
0.52
0.20
5.5
4.7
4.7
6.1
30.5
34.5
47.2
30.4
5
6
7
8
28
33
63
23 '
08-08-88
0.27
0.24
0.23
0.74
5.3
5.9
3.4
6.4
34.6
39.5
30.6
43.2
9
21
. 08-09-88
0.39
3.6
39.5
10
28
08-10-88
0.59
5.5
49.8
. 11
68
08-11-88
0.21
5.3
28.5
12
13
69
16
08-12-88
0.15
. 0.21
3.6
2.1
28.6
35.7
14
21
08-14-88
0.23
* N A = N ot analyzed.
NA* 34,3
49
Table 10. Shrew capture and metal concentration data.
Vole Number
Capture Data
Trap Site Number
Dale Captured
Kidnev Metal Concentration ( a s ./2. wet W e ie h t) Data
Cadmium
Copper
Zinc
Swamp Gulch Study Site
I
44
08:07-88
0.49
8.8
313
2
43
08-08-88
0.30
5.2
28.4
3
4
27
32
08-10-88
0.46
0.22
9.0
4.7
28.3
24.7
.5
6
33
41 .
08-11-88
0.44
0.08
7.8
3.8
31.1
29.9
7
39
08-12-88
0.23
5.6
34.5
8 '
30
08-14-88
0.55
6.6
34.9
Hardscrabble Creek Control Site
I
■2
44
71
08-08-88
0.10
0.15
6.2
NA*
312
NA
3
22
08-09-88
0.10
4.2
313
4
'5
6
35
42
45
08-10-88
0.09
0.05
0.12
5.6
5.0
5.5
30.2
28.8
30.8
7
8
49
19
08-11-88
0.17
0.10
4.3
3.3
34.9
31.9
* NA = Not analyzed.