&EPA
United States
Environmental Protection
Agency
Environmental Monitoring
and Support Laboratory
P.O. Box 15027
Las Vegas NV 89114
EPA-60O/3-78-054
May 1978
Research and Development
Ecological
Research Series
Factors Influencing
the Volatilization
of Mercury from
Soil
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development. U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal spe-
cies, and materials. Problems are assessed for their long- and short-term influ-
ences. Investigations include formation, transport, and pathway studies to deter-
mine the fate of pollutants and their effects. This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/3-78-054
May 1978
FACTORS INFLUENCING THE VOLATILIZATION OF MERCURY FROM SOIL
By
Robert D. Rogers and James C. McFarlane
Monitoring Systems Research and Development Division
Environmental Monitoring and Support Laboratory
Las Vegas, Nevada 89114
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY
LAS VEGAS, NEVADA 89114
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DISCLAIMER
This report has been reviewed by the Environmental Monitoring and
Support Laboratory—Las Vegas, U.S. Environmental Protection Agency, and
approved for publication. Mention of trade names or commercial products
does not constitute endorsement or recommendation for use.
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FOREWORD
Protection of the environment requires effective regulatory actions
which are based on sound technical and scientific information. This informa-
tion must include the quantitative description and linking of pollutant
sources, transport mechanisms, interactions, and resulting effects on man
and his environment. Because of the complexities involved, assessment
of specific pollutants in the environment requires a total systems approach
which transcends the media of air, water, and land. The Environmental Moni-
toring and Support Laboratory-Las Vegas contributes to the formation and
enhancement of a sound monitoring data base for exposure assessment through
programs designed to:
1 develop and optimize systems and strategies for moni-
toring pollutants and their impact on the environment
demonstrate new monitoring systems and technologies by
applying them to fulfill special monitoring needs of
the Agency ' s operating programs
A study was conducted to determine some of the factors responsible for
the volatilization of mercury from soils amended with mercury. It was dis-
covered that the amount of mercury lost from the soil could be correlated
with the amount of mercury in the soil that is solubilized by ammonium
nitrate. In addition it was found that the volatilization was mediated
by microorganisms. The conclusions can be beneficial in designing experi-
ments dealing with mercury compounds and soils and also in the interpretation
of data gathered by other investigators. Users who should find the report
of value include the Office of Air Programs, Office of Toxic Substances,
laboratories within the Office of Research and Development, other Federal
agencies, University and industrial research staffs.
Morgan
Director
Environmental Monitoring and Support Laboratory
Las Vegas , Nevada
iii
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ABSTRACT
Mercury volatilization from soils amended to 1 ppm mercury with mercuric
nitrate ceased within 1 week after application. During the first week, 20%
of the applied mercury was lost from a silty clay-loam soil and 43% was lost
from a loamy sand soil. Volatilization of Hg from the loamy sand soil re-
sulted in a concurrent decrease in ammonium nitrate-extractable mercury.
Other work with sterile soil indicates that the volatilization was-mediated
by microorganisms.
IV
-------
CONCLUSIONS
Mercury (Hg) when applied to soil in a soluble form was initially very
rapidly volatilized from the soil. The rate of volatilization decreased
with time until it approached zero even though the soil still contained 50'
to 80% of the applied Hg. Increasing the concentration of soil Hg increased
the period of maximum volatility.
Volatilization is the result of microbial action. The rate is deter-
mined by the availability of Hg to the microbes. This in turn is determined
by many factors including soil texture and organic matter content.
RECOMMENDATIONS FOR FUTURE RESEARCH
Clarification of how Hg is bound in soil is needed. Also, information
on the volatility of various species of Hg is needed to understand the com-
plexities of Hg contamination of soil. It is likewise important to determine
the microorganisms involved in these reactions in order to understand and
predict mercury movement and its potential threat to food contamination.
INTRODUCTION
Interest in the environmental cycling of Hg has turned to the trans-
formation of Hg into forms other than organics. It is known that Hg
applied to the soil in many chemical forms can be lost as volatiles (Alberts
et a^., 1974; Kimura and Miller, 1964; Hitchcock and Zimmerman, 1957).
However, no definitive .study on the volatility rate, chemical speciesxfonned,
and binding of mercury in soil has been reported. What mediates the volatili-
zation of Hg from soil systems is not well understood. Kimura and Miller
(1964) noted that autoclaved soils showed a decreased loss of Hg vapor,
thus indicating a biological interaction. Specific microorganisms have been
isolated from lake and river sediments (Izaki, 1977; Holm and Cox, 1975;
Avotins and Jenne, 1975; Summers and Silver, 1972; Tonomura, Maeda, and
Futai, 1968) which reduce ionic Hg to elemental Hg. These same microbes
can be found in aerobic soil; therefore, it is reasonable to assume that
there can be biological reduction and volatilization of Hg from natural and
agricultural soils. The duration and rates of Hg volatilization after
application are not available. In addition, the solubility of Hg in the
soil solution as related to the volatility has not been determined.
-------
A study was conducted to investigate the volatilization of Hg from
amended soils, the rate of loss, the chemical and biological availability
of Hg in soil, and whether such volatility is of a biological origin.
MATERIALS AND METHODS
Two soils, a loamy sand and a silty clay-loam, were used for this study.
They were collected from the upper 10 centimeters (cm) of the Ap horizon
(plow layer) in an agricultural area of southern Nevada. The moist soil
was processed through a 2-millimeter (mm) sieve and stored at room tempera-
ture in plastic bags. Some physical and chemical properties of the soils
are listed in Table 1. Sterilized soil was prepared by steam autoclaving
200-gram (g) quantities at 121° C for 4 hours. After 3 days the samples
were reautoclaved. To insure that the soils were indeed sterile, 0.1 g
of each soil was spread over the surface of nutrient agar in a petri dish.
These samples were then incubated for 1 week. No growth was seen on the
inoculated dishes.
TABLE 1. PHYSICAL AND CHEMICAL PROPERTIES OF SOIL
Soil
(Texture
Classification)
Series
Sand
Cation
Exchange
Clay Organic Capacity
% Carbon meq/lOOg pH
Sand
(Loamy Sand)
Bluepoint - a member of
the mixed thermic family
of Typic Torripsamment
79.8 3.5
0.53
4.3
9.0
Clay
(Silty Clay
Loam)
Overton - a member of 14.7 34.4 3.44 29.0
the fine montmorillonitic
calcareous thermic family
of Mollic Haplaquepts
7.8
Mercuric nitrate [Hg(NO3)2] was used to amend the soil. To each portion
of soil (20 g), 20 micrograms (yg) of Hg was added and stirred. This resulted
in a concentration of 1 part per million (ppm) Hg. Radioactive mercury
[203Hg(NO3)2] was mixed with the stable Hg(NO3)2 before the soil addition.
Those soils from which volatile Hg was to be determined received 40 nano-
curies (nCi) of 203Hg and the soils used for extraction purposes received
4 nCi of 203Hg. The mixed solution was such that 2 milliliters (ml) of
solution contained the desired amount of both stable and radioactive Hg.
The Hg solution was added to 20 g of soil contained in 250-ml polyethylene
bottles. After addition, distilled water was added to bring the soil
moisture to 50% of the soil moisture-holding capacity. The bottles with
their contents were weighed daily and the amount of water lost through
-------
evaporation was replaced as necessary. The bottles were closed with rubber
stoppers containing connections for inlet and outlet air lines. All bottles
were flushed during the study at a rate of 20 cubic centimeters per minute
(cc/min) with water-saturated/ compressed air.
Air flushed from the bottles being used for the volatility experiments
was passed through a charcoal collector located inside a side-hole scintil-
lation crystal. Flexible tubing used to connect the bottle to the collector
had a polyethylene liner. The charcoal collector was made from a 10-ml
volumetric pipette cut to length, with the bulb being filled with charcoal
pulverized to a 16 mesh.
Air from bottles whose contents were to be used in the extraction por-
tion of this study was passed through charcoal traps connected to the outlet
tubes of the rubber stopper. These traps were used as a safety measure and
not to determine volatile Hg. It was not necessary to change them during
the course of the study.
Each of the two side-hole scintillation crystals was connected to a
single-channel analyzer and the output was recorded on a strip chart recorder.
In this way a continuous record was obtained of the amount of volatilization
in terms of 203Hg disintegrations as cpm. The charcoal collectors were
changed 2 to 4 times a day during the first 72 hours of each experiment to
insure that the cpm rate did not go off scale. The bottles were maintained
at 25° C in water baths. Figure 1 is a representation of the experimental
set up.
Lead Shield
Valve
Air Flow At 0.1 LPH
At 10 PS1
BoUle Containing Soil Sample
3 ^Charcoal Filter
Scintillation
Crystal
P.M. Tube
Figure 1.
Strip
Chart
Recorder
Representation of the experimental setup for determining the
rate of Hg volatilization.
-------
After an experiment, the counts per minute (cpm) which had been con-
tinously recorded on graph paper were converted to a more meaningful form by
applying appropriate corrections for decay, specific activity, efficiency
and unit conversion. The slope of the line was then determined at 1-hour
intervals and the results presented as the Hg volatility rate (nanograms per
hours , ng/h) .
Soils amended with Hg were subjected to different extracting agents
after 24 hours of incubation in order to determine one suitable for use.
These solutions included H20, IN NH^NOs, and DTPA (Follett and Lindsay,
1971) . Each extraction was for 18 hours and included vigorous agitation on
a rotary shaker. The soil mixture was then centrifuged and the supernatant
was passed through a Whatman number 1 filter paper. The resulting clear
extract was used for the 203Hg determination. Table 2 gives the amount of
the applied Hg which was extracted from each of the soils. In all subse-
guent experiments 1N_ NHi^NOs was used for the extractions.
Experiments were designed so that volatile mercury was determined from
one set of replicates and the extractable and soil-bound mercury from another
set. By combining these results a budget could be reconstructed. Agreement
was generally good between the amount of mercury lost via volatilization as
determined by integrating the loss-rate curve and the amount determined by
subtracting the amount remaining as soil-bound and extractable from the
original amount of the amendment. However, there was one exception where
there was a discrepancy of 18% between these two methods of determining loss.
Because of greater precision the results of the direct analysis of the
volatile mercury are presented as the most reliable measure of the amount
lost via this route. The amount of mercury in the 1N_ NHt»NO3-wash solution
and the amount remaining in the soil after extraction were determined by
counting the gamma activity on a sodium iodide scintillation crystal using
a multi-channel analyzer. For convenience in interpretation, the data are
presented so that the volatility rate is superimposed over the data depict-
ing the soluble and nonsoluble Hg. This was done to allow visualization of
how changes in loss rate were correlated with amounts of mercury residual
in the soil as soluble and nonsoluble compounds.
TABLE 2. PERCENT MERCURY EXTRACTED FROM SOIL WITH
VARIOUS EXTRACTANTS AFTER 24-HOUR INCUBATION
% Recovered % Recovered
Extractant from Sand from Clay
HaO 8.5 0.6
IN NHi>NO3 20.5 0.6
DTPA 8.2 0.6
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RESULTS
Various combinations of soil type, Hg concentration, and sterile and
natural soils were investigated. Replicates of .experimental trials yield-
ed similar results but varied slightly in summation of the mercury budgets.
Yet all replicates 'gave similar rates, thus representative curves will be
presented instead of the entire data collected. When sandy soils were
amended with 20 \ig Kg/20 g soil (1 ppm Hg), 43% of the applied mercury was
lost within the first 6 days. The data presented in Figure 2 show that
volatilization increased reaching a peak rate at about 40 hours after the
Hg was added. The rate of decreasing IN NHi»NO 3-soluble and nonsoluble
mercury content was greatest when the volatility rate was at its maximum.
Soluble Hg decreased from 30% of the amount initially applied to Jabout 2%
at the termination of these tests. The volatility rate decreased to a
minimum by about 100 hours after which there appeared to be a steady state
established. Some volatility continued at a rate which appeared to be in
equilibrium with the amount of soluble Hg.
Volatile Hg
NH4NO3-Soluble
Non- soluble
o>
at
o
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o
IOOQ
000000
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oooooooooo
IOOOOOOOOOOJJO
ooooooooooJoo
1000000000*3000
YJOOOOOOOO
Ifc
oooo
ooo
VPOO
"ISJPOO
7.5-
- 220
- 200
- 180
-160
-140
- 120
-100
• 80
-60
-40
-20
O)
O)
£
15
n
o
80 90 100 110 120 130 140.
Time(h)
Figure 2. Rate of Hg volatilization and Hg remaining in sandy soil amended
to 1 ppm Hg. The soil Hg (yg) axis is nonzero.
-------
Sandy soil was also amended with Hg(N03>2 at a concentration of 10 yg
Hg/g soil (10 ppm Hg). During the 6-day incubation period, approximately
50% of the applied Hg was lost in the vapor form (Figure 3). There was a
lag time of some 20 hours before the onset of rapid volatilization, but in
this case no distinct volatilization peak was noted, rather the maximum
rate of between 700 and 900 ng Hg/h persisted for some 50 hours before
200.
O)
S^
at
o
CO
Volatile Hg
NH4NO3- Soluble
niniiiiii Non-Soluble
IOOOOOO
DOOOOOO
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190 - 3OOOOOOOOOO
oooooooooooooooo
oooooooooooooooooooo
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oooooooooo
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ooooooooooooooooooooooooooo
oooooooooooooooooooooooooooooo
ooooooooooooooooooooooooooooooooooo
oooooooooooooooooooooooooooooooooooooooo
ooooooooooooooooooooooooooooooooooooooooooooooo
ooooooooooooooooooooooooooooooooooooooooooooooooooo
ooooooooooooooooooooooooooooooooooooooooooooooooooooooo
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oooooooooooooooooooooooooooooooooooooooooooooooooopoooooooooo
ooooooooooooooooooooooooooooooo
ooooooooooooooooooooooooooo
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I
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o
1
1
10
80 90 100 110 120 130 140
Figure 3.
Time (h)
Rate of Hg volatilization and Hg remaining in sandy soil amended
to 10 ppm Hg. The soil Hg (pg) axis is nonzero.
gradually decreasing. Even at the end of the test there was a substantial
rate of volatile Hg loss. A decrease in the 1N_ NHi»NO3-soluble Hg was noted
after 12 hours and continued throughout the study (e.g., at 144 hours only
16% of the applied Hg was still soluble versus 50% at the start).
Steam-autoclaved sandy soil amended with Hg(NOs)2 at a concentration
of 20 yg Hg/20 g soil (1 ppm) had a total volatile loss of only 10% of the
applied Hg after 144 hours (Figure 4). There was no initial lag in vola-
tilization as with the non-sterile sand trials. The rate of Hg loss decreas-
ed rapidly during the first 16 hours and then remained about constant through-
out the duration of the test. The decrease in IN NH^NOs-soluble Hg during
the test period was negligible.
The pattern of Hg loss from the clayey soil was quite different from
that of the sandy soil. Clayey soil amended to a concentration of 1 ppm
Hg as Hg(NOs)2 lost a total of 20% of the applied Hg during the 144-hour
examination period (Figure 5). Of this amount, 80% of the volatile loss
occurred within the first 36 hours. Since there was no IN NH^NOa-extractable
Hg from this soil, the loss of Hg was from the non-extractable fraction.
In addition there was no lag period between Hg applications and peak Hg
volatilization rate with any of the treatments of this soil.
-------
[^=1 Volatile Hg
NHiNOa-Soluble
Non-Soluble
-120
'at
o>
20 30 40 SO SO 70 80 90 100 110 120 130 140
Figure 4.
Time (h)
Rate of Hg volatilization and Hg remaining in sterilized sandy
soil amended to 1 ppm Hg. The soil hg (yg) axis is nonzero.
O> 17.5 -
=] Volatile Hg
Non-Soluble
10 20 30 40 50 60 70 80 90 100 110 120 130 140
f
£
Time (h)
Figure 5. Rate of Hg volatilization and Hg remaining in clayey soil
amended to 1 ppm Hg. The soil Hg (yg) axis and the volatile
Hg (ng/h) axis are nonzero.
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Clayey soil amended to 10 ppm Hg as Hg(N03)2 volatilized 31% of this
Hg during the test period (Figure 6). The bulk of this loss was during the
first 3 days with an initial loss rate of 1,500 ng/h. During the first
24 hours of incubation, a small amount (4.5% of the total) of the Hg was
found to be IN NH^NOa-extractable.
Steam-sterilized clay lost only 2% of the applied 20 yg Hg (Figure 7).
No IN NH,,N03- extractable Hg was found.
DISCUSSION
The data from this study show that Hg was lost from soils amended with
Hg(N03)2. In every case, except one (Figure 3), almost 100% of the volatili-
zation of applied Hg occurred within the first week. There was a considerable
difference between the sand and clay. In general, the volatilization from
clay was faster to start but less of the Hg was lost overall. Increasing
the Hg concentration from 1 ppm to 10 ppm increased the loss of Hg from the
sand by a factor of 11 and the clay by 15 times (Figures 3 and 6).
CO
Volatile Hg
NH4NO3-Soluble
Non-Soluble
O)
o>
X
10 20 30 40 50 60 70 80 90 100 110 120 130 140
Time (h)
Figure 6. Rate of Hg volatilization and Hg remaining in clayey soil
amended to 10 ppm Hg. The soil Hg (yg) axis is nonzero.
8
-------
Volatile Hg
Non-Soluble
O)
o>
z
o
CO
-30
-20
-10
10 20 30 40 SO 60 70 60 90 100 110 120 130 140
O)
c
a
I
Time (h)
Figure 7. Rate of Hg volatilization and Hg remaining in sterile clayey
soil. The soil Hg (yg) axis is nonzero.
Autoclaving the soils had a pronounced effect on the amount of Hg
lost over the duration of these tests (144 hours, Figures 4 and 7). In
the case of the sandy soil, this reduction was from 8.6 yg Hg to 2 yg Hg
and a change of 4 yg Hg to 0.4 yg Hg for the clay. To insure that the Hg
loss was initiated biologically, both soils were inoculated with 1 g of
each of their respective nonsterile soils after 160 hours of incubation.
No effect was noted with the clayey soil but within 8 hours the inoculated
sandy soil started volatilizing Hg at a high rate (Figure 8). The volatiliza-
O)
o>
o
—r
30
—r
40
50
—1 T
60 70
—T
80
~~1 I 1 1 1 1 1 1 1 1 1 1 1 T
90 100 120 130 140 ISO 160 170 180 ISO 200 210 220
Figure 8.
Time (h)
Rate of Hg volatilization from sterile sandy soil. Arrow
indicates when soil was inoculated with 1 g of nonsterile
soil.
-------
tion from the sandy soil reached a peak 22 hours after inoculation. Total
Hg loss after 214 total elapsed hours was 31%. Since the pool of IN NHnNOs-
extractable Hg had not been reduced in the sandy soil during the period of
sterile incubation (Figure 4), it is speculated that this fraction was being
volatilized. There was apparently no Hg available for volatilization in
the clayey soil.
These data clearly indicate that Hg loss from these soils was mediated
by a biological system, although this may not be the case for all soils
since it has been shown that humic acid solutions can mediate the loss of
ionic mercury (Hg++) as elemental Hg (Alberts et al., 1974). Workers in
the area of aquatic Hg cycling have shown in recent years that there are
several microorganisms which can cause the volatilization of Hg. These
microbes include Eseheriah'ia coli, staphyloaeus aureus, and several species
of Pseudomonas(Summers and Sugarman, 1974). Mercury loss from cultures of
Pseudomonae amended with Hg++ was found to be elemental Hg (Tonomura,
Furukawa, and Yamada, 1972). Some algae are also capable of causing the
volatilization of Hg from solutions amended with HgClz (Ben-Bassat and
Mayer, 1975). The consensus is that these organisms cause Hg loss by the
reduction of Hg++ to elemental Hg which is then lost because of its elevated
vapor pressure (Tonomura, Maeda, and Putai, 1968; I2aki, 1977). It should
be noted that while the pathways for volatile Hg in these soils are biologi-
cal, the transformation of Hg++ into methyl Hg is abiological (Rogers, 1977,
1976). Methylroercury also has an elevated vapor pressure and, when formed
one molecule at a time, it too is suspected of being volatile.
In the clayey soil the volatility rate continuously decreased while
in the sandy soil the rate remained relatively stable for a few hours,
followed by a significant increase. Since the enzyme system responsible
for volatilization has been shown to be inducible (Furukawa and Tonomura,
1971) it may be that such an induction wa~ responsible for the increases
observed in the sandy soils (Figures 2 and 3). The lack of a similar
pattern in the clayey soils may indicate the lack of a similar inducible
enzyme system or more probably, the removal of mercury from microbe avail-
ability The presence of only a small IN NH4NOj-extractable fraction in
the 10-ppm treatment (Figure 5) and no detectable IN NH^NOs-soluble frac-
tion in the 1-ppm treatment (Figure 4) of the clayey soils may also repre-
sent the lack of availability.
The number of soil microbes at the time of dosing were 30 x 106/g soil
and 2" soil for the *^^^ ~^^*^0^eci*S
ofi^r^^^
in the clayey and sandy soils were in »PP^tMt^"'a^^^re collect-
ratio of the numbers of microbes. However, insufficient data were
ed to ascertain if this was a cause-effect relationship.
in all cases (except sand with 10 ppm Kg) the rate of Hg volatilRation
decreased to near zero long before all the applied Hg was used (80 to /i*
remaining in clay and 50 to 57% remaining in sand). In the sandy soil tne
decrease in volatility correlated with a decrease in the amount IN NH.jNU3-
extractable Hg and to a lesser extent with a decrease in the nonsoluble
10
-------
fraction (Figures 2 to 4). However, since the volatilization of Hg decreased
to near zero when the extractable Hg was exhausted, it is speculated that,
in the case of the sand, Hg was lost only from the soluble fraction and the
easily exchangeable fraction of the nonsoluble Hg. Data from studies on
the volatile loss of Hg from water also link volatility with Hg availability.
It has been shown that, as the concentration of complexing agents such as
chlorine and bromine increase, the amount of Hg volatilized decreases because
of a decrease in microbially available Hg (Jenne and Avotins, 1975). In
other work with nonsterile solutions, it was shown that the amount of Hg
volatilized from the solution depends on the amount of Hg which has become
unavailable for microbial action due to combination with organic matter
(Avotins and Jenne, 1975). The same authors reported that volatilization
had almost ceased after 96 hours. These data are comparable with the find-
ings from the sandy soil as far as the effect of Eg-complexing material,
biological interactions on Hg volatilization, and the time required for
the volatilization of the biologically available Hg. Note that during
the time course of the sterile sand study, the extractable Hg content
remained unchanged (Figure 4). Results from this study also support the
hypothesis that the decrease in Hg volatility with time is caused by a
loss of available Hg and not because the Hg is becoming more tightly bound
with time.
While the volatilization of Hg from the clayey soil is also obviously
a biological phenomenon (Figure 5 and 7), the Hg being volatilized was not
correlated with a IN NHt,NO3-extractable source. Even though the Hg was not
1N[ NHi»NC>3-extractable, some 20 to 31% of it was biologically available
(Figures 5 and 6). This would indicate that the Hg was initially in a form
available to microbes but not in solution or easily removed from the soil
exchange sites. How the Hg is being bound is not known but it has been
shown that Hg is tightly complexed on organic matter and cannot be replaced
with another ion except Hg (Strohal and Huljev, 1971). Since the clayey
soil was higher in organic matter than the sandy soil, the soil organic
matter could also be a viable factor in Hg retention by the clayey soil.
The same could also be true for the inorganic exchange sites. Because the
experiments were not designed to isolate clay or organic matter as factors
affecting volatilizations, it is not possible from these data to emphasize
which has the greater effect. It is possible that the amount of observed
Hg volatility is not a true indication of the total Hg vapor occurring in
the soil. This is because both clay and organic matter can sorb vapor-
phase Hg (Krenkel, 1974; Trost and Bisque, 1971).
The data from both the sandy and clayey soils show that the amount of
Hg volatilized from a soil is not an indication of the total amount of Hg
contained by the soil. Conversely, knowing the total amount of Hg con-
tained by a soil will not give an indication of potential losses due to
volatilization. But, with more information from different soils some
idea on how Hg is being bound by soils could be obtained from determining
what portion of the total soil Hg is being volatilized.
The increase in volatility in response to the increase in Hg concentra-
tion (Figures 3 and 6) indicates that the organisms responsible for volatili-
zation are capable of processing large g_uantities of Hg. It was apparent
11
-------
over 150 Sof th^in^ ^ "oon^ ^^ SOil had not been saturated since
almost ceased with ^ 2° W °f Hg remaine* after volatilization had
Figure 3) Ha 'was bei ^ «oi1' even after 170 hours (not shown in
were to continue at%h? ^ ** * "te °f 26° n^ H^- « evolution
' ' 95% of the appiied
0d int
same concentration as that fonnf i ^ remaining Hg to about the
it ceased volatilization (11 "g). ^ "^ ^^ Wlth 10 ^ °f Hg
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in°wi?f; *"af E' A"
515-519! 1™1 ^' emCa St^li^tion. J. Environ. Qual. 4:
inw * The Time stability of Dissolved Mercury
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ir ' DTPA-extractable Zinc,
iron Manganese, and Copper in Soils Following Fertilization.- Soil
Sci. Soc. Amer. Proc. 35^600-602, 1971. -
5. Furukawa, K. and K. Tonomura. Enzyme System Involved in the Decomposi
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10. Kimura, Y. , and V. L. Miller. The Degradation of Organomercury Fungi-
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11. Krenkel, P. A. Mercury: Environmental Considerations. Part II.
Critical Reviews in Environ. Control 4:251-339. 1974.
12
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12. Rogers, R. D. Abiological Methylation of Mercury in Soil. J. Environ.
Qual. 6_:463-467, 1977.
13. Rogers, R. D. Methylation of Mercury in Agricultural Soils. J. Environ.
Qual. 5^:454-458, 1976.
14. Strohal, P., and D. Huljev. Investigation of Mercury-pollutant Interac-
tion with Humic Acids by Means of Radiotracers. In Nuclear Techniques
in Environmental Pollution. International Atomic Energy Agency,
Vienna, 1971, p. 439.
15. Summers, A. O., and L. I. Sugarman. Cell-free Mercury (II)-reducing
Activity in a Plasmid-bearing strain of Esoheriahia coli. J. Bacteriol.
119:242-249.
16. Summers/ A. O., and S. Silver. Mercury Resistance in a Plasmid-Bearing
Strain of Eseheriahia aoli. J. Bacteriol. 112:1-228-1236, 1972.
17. Tonomura, K., K. Furukawa, and M. Yamada. Mercury Transformation in
the Environment. II. Microbial Conversion of Mercury Compounds.
pp. 115-133. In_ F. Matsumura (ed) Environmental Toxicology of
Pesticides. Academic Press, NY, 1972.
18. Tonomura, K., K. Maeda, and F. Futai. Studies on the Action of
Mercury-Resistant Microorganism on Mercurial. II. The Vaporization
of Mercurials Stimulated by Mercury Resistant Bacterium. J. Ferment.
Technol. 46_: 685-692, 1968.
19. Trost, P. B., and R. E. Bisque. Differentiation of Vaporous and Ionic
Mercury in Soils. Geochem. Exlor. 11^:276-279, 1971.
•fy U.S. GOVERNMENT PRINTING OFFICEI 1 978 -78 5-92S/ t 21 8 9-1
13
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TECHNICAL REPORT DATA
(Please read iNitnictions on the reverse before completing)
i. REPORT NO.
EPA-600/3-78-054
I. RECIPIENT'S ACCESSION-NO,
4. TITLE AND SUBTITLE
FACTORS INFLUENCING THE VOLATILIZATION OF MERCURY
FROM SOIL
5. REPORT DATE
May 1978
6. PERFORMING ORGANIZATION CODE
7, AUTHOR(S)
Robert D. Rogers and James C. McFarlane
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Monitoring and Support Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Las Vegas, NV 89114
10. PROGRAM ELEMENT NO.
1AA602
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency-Las Vegas, NV
Office of Research and Development
Environmental Monitoring and Support Laboratory
Las Vegas, NV 89114
1ST. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/600/07
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Mercury volatilization from soils amended to 1 ppm mercury with mercuric
nitrate ceased within 1 week after application. During the first week, 20%
of the applied mercury was lost from a silty clay-loam soil and 43% was lost
from a loamy sand soil. Volatilization of Hg from the loamy sand soil re-
sulted in a concurrent decrease in ammonium nitrate-extractable mercury.
Other work with sterile soil indicates that the volatilization was mediated
by microorganisms.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Mercury
Radioactivity
Soil chemistry
Inorganic chemistry
Volatilization
07B
08M
14B
18B
18. DISTRIBUTION STATEMENT
RELEASE TO THE PUBLIC
19. SECURITY CLASS (This Report)
UNCLASSIFIED
21. NO. OF PAGES
20
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
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