300
A. Gnamus and M. Horvat
polluted environment and the controls were relatively greater in roe deer tissues,
and relatively smaller in vegetation samples. Mercury concentrations in roe deer
tissues from the affected Idrija mining area are approximately 1 or 2 orders of
magnitude higher than those of the controls, depending on the distance of their
site of origin from the smelter (see Fig. 4).
A comparison of Hg content between various roe deer tissues and their
composite plant diet collected within the clustered contamination zones A and B in
the Idrija area and the control areas showed some interesting features. In Zone A
roe deer brain tissue Hg levels were approx. 80 to 200 times lower than in the
composite vegetation, except for the sampling area I-I with approx. 1000 x higher
vegetation values. In contrast, roe deer kidney Hg levels from this cluster were
approx. 1.5 times higher than the composite roe deer diet. Again, the exception was
sampling area I-I with a reversed animal-to-plant ratio. In Zone B brain Hg levels
were approx. 50 times smaller, and kidney Hg levels were approx. 3 to 7 times higher
than in the composite vegetation samples of the area. Mercury concentration
ranges for other roe deer tissues in relation to the Hg values in the composite plant
samples representing roe deer diet deviate from the accumulation patterns found
in kidney and brain, and show animal- to -plant ratios between the two extremes. In
the contaminated area roe deer liver and fur Hg concentration levels were usually
approx. within the same range as in their vegetation diet. For the controls, Hg
values in various roe deer tissues were approx. 15 to 60 times lower than in the
composite vegetation samples, and fur Hg concentrations deviated from the
expected approximate equality with vegetation Hg levels, being about 8x lower.
The trends in Hg content of the composite plant samples representing browsed roe
deer diet and selected roe deer tissues as a function of the distance from the source
of Hg pollution are indicated by the lines between mercury values (see Fig. 4) and
resemble those in other environmental samples (Kosta et al. 1974b; Hess 1993;
Gnamus et al. 1996). Evidently, mercury values decrease with the distance from the
mercury source, except in the sampling area 1-6. Despite being reduced, Me-Hg
concentrations in composite plant samples and roe deer tissues still reveal
deviations in the sampling area 1-6. The deviations in the sampling area 1-6 show
that distance from the pollution source cannot be the only measure of pollution
monitoring. The actual pollution must be accessed through a more complex
approach. Considering the distance of the sampling area 1-6 from the pollution
source, enhanced T -Hg concentrations established in the 1-6 top soil (Gnamus et al.
1996), and expressed in biota samples, may be influenced by the prevailing winds
which sweep airborne Hg westerly from the heavily contaminated mine-smelter
area. Since the sub-soil Hg content disagrees with deviating elevated values in the
top soil (Gnamus et al. 1996) and biota from the area, it is very likely that the
enhanced mercury concentrations in area 1-6 may be related to enhanced airborne
Hg contamination rather than to some undiscovered bed-rock mercury deposits in
the area. The elevated Hg contents in the area could arise due to a higher Hg
deposition related to airborne pollution from the Idrija smelter chimney. However,
since Hg concentrations in soil and plants have been changing little during the past
5 years, despite the drastic reduction of mercury production in the smelter, the
elevated Hg contents in samples from sampling area 1-6 are most probably related
to one or several of the many undiscovered tailing sites from the past, which are
A. Gnamus and M. Horvat
polluted environment and the controls were relatively greater in roe deer tissues,
and relatively smaller in vegetation samples. Mercury concentrations in roe deer
tissues from the affected Idrija mining area are approximately 1 or 2 orders of
magnitude higher than those of the controls, depending on the distance of their
site of origin from the smelter (see Fig. 4).
A comparison of Hg content between various roe deer tissues and their
composite plant diet collected within the clustered contamination zones A and B in
the Idrija area and the control areas showed some interesting features. In Zone A
roe deer brain tissue Hg levels were approx. 80 to 200 times lower than in the
composite vegetation, except for the sampling area I-I with approx. 1000 x higher
vegetation values. In contrast, roe deer kidney Hg levels from this cluster were
approx. 1.5 times higher than the composite roe deer diet. Again, the exception was
sampling area I-I with a reversed animal-to-plant ratio. In Zone B brain Hg levels
were approx. 50 times smaller, and kidney Hg levels were approx. 3 to 7 times higher
than in the composite vegetation samples of the area. Mercury concentration
ranges for other roe deer tissues in relation to the Hg values in the composite plant
samples representing roe deer diet deviate from the accumulation patterns found
in kidney and brain, and show animal- to -plant ratios between the two extremes. In
the contaminated area roe deer liver and fur Hg concentration levels were usually
approx. within the same range as in their vegetation diet. For the controls, Hg
values in various roe deer tissues were approx. 15 to 60 times lower than in the
composite vegetation samples, and fur Hg concentrations deviated from the
expected approximate equality with vegetation Hg levels, being about 8x lower.
The trends in Hg content of the composite plant samples representing browsed roe
deer diet and selected roe deer tissues as a function of the distance from the source
of Hg pollution are indicated by the lines between mercury values (see Fig. 4) and
resemble those in other environmental samples (Kosta et al. 1974b; Hess 1993;
Gnamus et al. 1996). Evidently, mercury values decrease with the distance from the
mercury source, except in the sampling area 1-6. Despite being reduced, Me-Hg
concentrations in composite plant samples and roe deer tissues still reveal
deviations in the sampling area 1-6. The deviations in the sampling area 1-6 show
that distance from the pollution source cannot be the only measure of pollution
monitoring. The actual pollution must be accessed through a more complex
approach. Considering the distance of the sampling area 1-6 from the pollution
source, enhanced T -Hg concentrations established in the 1-6 top soil (Gnamus et al.
1996), and expressed in biota samples, may be influenced by the prevailing winds
which sweep airborne Hg westerly from the heavily contaminated mine-smelter
area. Since the sub-soil Hg content disagrees with deviating elevated values in the
top soil (Gnamus et al. 1996) and biota from the area, it is very likely that the
enhanced mercury concentrations in area 1-6 may be related to enhanced airborne
Hg contamination rather than to some undiscovered bed-rock mercury deposits in
the area. The elevated Hg contents in the area could arise due to a higher Hg
deposition related to airborne pollution from the Idrija smelter chimney. However,
since Hg concentrations in soil and plants have been changing little during the past
5 years, despite the drastic reduction of mercury production in the smelter, the
elevated Hg contents in samples from sampling area 1-6 are most probably related
to one or several of the many undiscovered tailing sites from the past, which are