Mercury in Terrestrial Food Webs of the Idrija Mining Area
311
number of roe deer tissues obtained so far did not reflect the age of the animals,
probably because of the influence of the severe spatial exposure gradients.
Additional samples, especially from the heavily polluted Zone A inside the Idrija
valley, must be surveyed for more reliable results. However, as concerns Idrijan
roe deer (see Table 3: Zone A), positive age/T-Hg correlation was observed in
lungs (r2 = 0.73), but correlations in other tissues were not statistically
significant.
Sex differences cannot be observed from the data collected so far, since all the
culled animals, except two (one roebuck and one roecalf - see Table 3: R6 and
R8), were females.
To establish a relationship between the Hg content in tissues and the age/sex of
roe deer in this heavily polluted area, further studies with a greater number of
specimens are required.
4.8
Do Wildlife Reveal the Toxic Effects of Enhanced Hg
Concentration Values in the Heavily Polluted Environment?
So far, no visual damage was observed on the macro morphological level in roe
deer tissues despite some very high Hg concentrations, which greatly exceed the
maximum levels accepted under FAO/WHO regulations for food substances.
Since no apparent clinical signs of poisoning were observed either in plants or in
roe deer from the heavily polluted area in Idrija, we can confirm the evaluation of
the effects of Hg in the terrestrial environment given in the WHO-IPCS
Environmental Health Criteria (WHO 1989): "Acute effects would not be seen in
terrestrial plants growing in natural soils, nor in terrestrial birds or mammals".
Nevertheless, a variety of the stochastic effects related to the enhanced presence
of Hg in the Idrija environment may occur. They may result in various
potentially dangerous effects which are very difficult to establish and evaluate.
In order to identify any tissue damage it would be necessary to perform
histological and cytogenetic studies. On the other hand, a semimillenium of
intensive exploitation of mercury, resulting in highly elevated Hg concentrations
in the Idrija valley environment, may represent a period long enough to enable
organisms living in the heavily affected area to develop effective phylogenetically
conditioned mechanisms preventing adverse effects.
It is difficult to establish whether any harmful vegetational responses to the
heavy Hg pollution in Idrija area exist since no visual adverse effects were
observed which could be directly related to the highly elevated Hg concentrations. Perhaps the only visual sign of heavy pollution might be the absence of
the majority of plant species forming roe deer diet from the vegetation cover in
the most heavily contaminated Smelter Zone. However, this may be primarily the
consequence of enhanced S02 and flue gas emissions from the smelter chimney,
as well as the soil depth and characteristics.
It is important to stress that most forms of mercury are highly toxic to the
animals, which is not the case for plants (WHO 1989), except at very high
concentrations. Long-term retention and subsequent toxicity of Hg to plants may
311
number of roe deer tissues obtained so far did not reflect the age of the animals,
probably because of the influence of the severe spatial exposure gradients.
Additional samples, especially from the heavily polluted Zone A inside the Idrija
valley, must be surveyed for more reliable results. However, as concerns Idrijan
roe deer (see Table 3: Zone A), positive age/T-Hg correlation was observed in
lungs (r2 = 0.73), but correlations in other tissues were not statistically
significant.
Sex differences cannot be observed from the data collected so far, since all the
culled animals, except two (one roebuck and one roecalf - see Table 3: R6 and
R8), were females.
To establish a relationship between the Hg content in tissues and the age/sex of
roe deer in this heavily polluted area, further studies with a greater number of
specimens are required.
4.8
Do Wildlife Reveal the Toxic Effects of Enhanced Hg
Concentration Values in the Heavily Polluted Environment?
So far, no visual damage was observed on the macro morphological level in roe
deer tissues despite some very high Hg concentrations, which greatly exceed the
maximum levels accepted under FAO/WHO regulations for food substances.
Since no apparent clinical signs of poisoning were observed either in plants or in
roe deer from the heavily polluted area in Idrija, we can confirm the evaluation of
the effects of Hg in the terrestrial environment given in the WHO-IPCS
Environmental Health Criteria (WHO 1989): "Acute effects would not be seen in
terrestrial plants growing in natural soils, nor in terrestrial birds or mammals".
Nevertheless, a variety of the stochastic effects related to the enhanced presence
of Hg in the Idrija environment may occur. They may result in various
potentially dangerous effects which are very difficult to establish and evaluate.
In order to identify any tissue damage it would be necessary to perform
histological and cytogenetic studies. On the other hand, a semimillenium of
intensive exploitation of mercury, resulting in highly elevated Hg concentrations
in the Idrija valley environment, may represent a period long enough to enable
organisms living in the heavily affected area to develop effective phylogenetically
conditioned mechanisms preventing adverse effects.
It is difficult to establish whether any harmful vegetational responses to the
heavy Hg pollution in Idrija area exist since no visual adverse effects were
observed which could be directly related to the highly elevated Hg concentrations. Perhaps the only visual sign of heavy pollution might be the absence of
the majority of plant species forming roe deer diet from the vegetation cover in
the most heavily contaminated Smelter Zone. However, this may be primarily the
consequence of enhanced S02 and flue gas emissions from the smelter chimney,
as well as the soil depth and characteristics.
It is important to stress that most forms of mercury are highly toxic to the
animals, which is not the case for plants (WHO 1989), except at very high
concentrations. Long-term retention and subsequent toxicity of Hg to plants may