302
A. Gnamus and M. Horvat
From the data presented in Fig. 4 it is evident that the Hg concentration
differences in vegetation reflect the microterritorial fluctuations in terrestrial Hg
contamination better than roe deer tissues, whereas roe deer reflect the macroterritorial exposure gradient more efficiently. Since the living ranges of selected
roe deer specimens were probably very seldom restricted to the size of a
particular sampling area (1-1 to 1-7) only, roe deer tissue Hg concentrations
usually represent a measure of the contamination which is not entirely
dependent on the particular limited sampling location, as in soil profiles and
plant samples. However, the sampling areas I-I to 1-7, used for the collection of
soil profiles and vegetation samples, had to be restricted to a size of approx. 1.5
km 2 for operational reasons and to standardize the sampling conditions. The
living range of a particular specimen is also the main reason why roe deer is a
more useful bioindicator than various predator species as concerns monitoring
the exposure gradient of strong airborne Hg contamination in Idrija, which
features distinctively local character. Good agreement between environmental
and biota mercury concentration fluctuations related to the distance from the
source of Hg pollution shows that roe deer effectively take over the Hg levels
from their environment and efficiently reflect the Hg contamination pattern of
the area in which they live. Roe deer tissues from the contaminated region
expressed a large distinction in Hg contents compared to the controls. These data
indicate that roe deer tissues may be successfully used as an indicator of Hg
contamination in the terrestrial environment.
By comparing the data obained from roe deer tissue analysis to the Hg
concentration values measured in various environmental samples from the area,
we may conclude this section by stating that roe deer as a representative of the
terrestrial wildlife species sufficiently reflect the mercury exposure gradient
related to the distance of the site of their origin from the contamination source.
In addition, vegetation samples reflect the territorial Hg exposure gradient. The
use ofbioindicators is very important for Hg risk assessment since the plant and
animal tissue Hg values represent biologically available Hg, whereas ambiental
monitoring considering Hg in air or in soil profiles reflects external contamination mainly. Together they give us a fairly accurate picture of the size and
extent of contamination in a certain area.
4.4
The Concentrations of Total Mercury (T-Hg)
and Methylmercury Compounds (Me-Hg) in Roe Deer Tissue Samples
and Their Browsed Diet from the Heavily Polluted Area
As established by earlier studies concerning plant samples from the examined
area (Furlan and Kosta 1972; Stegnar 1973) and other Hg-contaminated areas
(Huckabee et al. 1983; Bargagli et al. 1986; Barghigiani et al. 1989; Ferrara et al.
1991), various terrestrial vascular plant species from the same sampling site show
important differences concerning tissue Hg concentrations. Regarding different
accumulation rates of terrestrial plant species related to the local/individual
factors (e.g. soil types, texture and properties, microenvironment, exposure of
A. Gnamus and M. Horvat
From the data presented in Fig. 4 it is evident that the Hg concentration
differences in vegetation reflect the microterritorial fluctuations in terrestrial Hg
contamination better than roe deer tissues, whereas roe deer reflect the macroterritorial exposure gradient more efficiently. Since the living ranges of selected
roe deer specimens were probably very seldom restricted to the size of a
particular sampling area (1-1 to 1-7) only, roe deer tissue Hg concentrations
usually represent a measure of the contamination which is not entirely
dependent on the particular limited sampling location, as in soil profiles and
plant samples. However, the sampling areas I-I to 1-7, used for the collection of
soil profiles and vegetation samples, had to be restricted to a size of approx. 1.5
km 2 for operational reasons and to standardize the sampling conditions. The
living range of a particular specimen is also the main reason why roe deer is a
more useful bioindicator than various predator species as concerns monitoring
the exposure gradient of strong airborne Hg contamination in Idrija, which
features distinctively local character. Good agreement between environmental
and biota mercury concentration fluctuations related to the distance from the
source of Hg pollution shows that roe deer effectively take over the Hg levels
from their environment and efficiently reflect the Hg contamination pattern of
the area in which they live. Roe deer tissues from the contaminated region
expressed a large distinction in Hg contents compared to the controls. These data
indicate that roe deer tissues may be successfully used as an indicator of Hg
contamination in the terrestrial environment.
By comparing the data obained from roe deer tissue analysis to the Hg
concentration values measured in various environmental samples from the area,
we may conclude this section by stating that roe deer as a representative of the
terrestrial wildlife species sufficiently reflect the mercury exposure gradient
related to the distance of the site of their origin from the contamination source.
In addition, vegetation samples reflect the territorial Hg exposure gradient. The
use ofbioindicators is very important for Hg risk assessment since the plant and
animal tissue Hg values represent biologically available Hg, whereas ambiental
monitoring considering Hg in air or in soil profiles reflects external contamination mainly. Together they give us a fairly accurate picture of the size and
extent of contamination in a certain area.
4.4
The Concentrations of Total Mercury (T-Hg)
and Methylmercury Compounds (Me-Hg) in Roe Deer Tissue Samples
and Their Browsed Diet from the Heavily Polluted Area
As established by earlier studies concerning plant samples from the examined
area (Furlan and Kosta 1972; Stegnar 1973) and other Hg-contaminated areas
(Huckabee et al. 1983; Bargagli et al. 1986; Barghigiani et al. 1989; Ferrara et al.
1991), various terrestrial vascular plant species from the same sampling site show
important differences concerning tissue Hg concentrations. Regarding different
accumulation rates of terrestrial plant species related to the local/individual
factors (e.g. soil types, texture and properties, microenvironment, exposure of