Mercury in the Town of Idrija (Slovenia)
After SOO Years of Mining and Smelting
v. MIKLAvCI<::
Due to mining and smelting processes, and due to the naturally increased contents of mercury in soil,
the wider surroundings of Idrija are contaminated with mercury. The Idrija ore deposit contains rocks
enriched with cinnabar originating from periods up to Middle Triassic. Native mercury can be found
primarily in Carboniferous clastic rocks which reach the surface in the western part of the ore deposit.
In the 1970S, when the production of mercury reached its peak, the first intensive studies of the
ecological cycle of mercury were made. New analytical techniques and improved methods for
determining the total mercury and methylmercury contents were introduced in order to study the
uptake and distribution of this element in the ground, air, water, plants, animals and man. After 20
years, systematic determinations of total mercury in environmental and biological samples were
started again. In our work, total mercury in air, lichens sampled in situ, transplanted lichens, carrots
and beans were determined, using gold amalgamation cold vapour atomic absorption spectrometry
(CV AAS) after acid decomposition under pressure, or in the case of air measurements, the double
amalgamation technique followed by CV AAS. Measured concentrations of total gaseous mercury in
air varied from 10 to 277 ng Hg m J. The total mercury contents in lichens sampled in situ were in the
interval between 3 to 23 fIg Hg g 1 dry sample (d.s.). The total mercury content in carrot ranges from
approximately 60 to 760 ng Hg g -I d.s. The concentrations of total mercury in beans were in the
interval between 2 to 23 ng Hg g-I d.s.
1
Introduction
The discovery of one of the world's largest mercury deposits in 1490 led to the
opening of the Idrija Mercury Mine, which, over a period of 500 years of
continuous operation, experienced exceptional technical, technological and
scientific development, which also left its mark on the town of Idrija. However,
500 years of mining activities produced harmful effects on the environment due
to pollution with mercury and, partly, ionizing radiation from radon and its
daughters. Over these 500 years, generations of Idrija miners extracted lO7000
tons of mercury (Hg) for commercial purposes. Taking into account all the
losses, which were particularly excessive in the early periods of extraction, it may
be estimated that the total quantity of extracted Hg surpassed 147000 tons.
The Idrija Mine operated successfully until the global Hg crisis in the 1970S. In
1969 the results of many years of research on the influence of Hg and its
compounds on the environment and humans were published in the United States
(Jensen and Jernelov 1969; Jernelov 1969). Large quantities of Hg had been found
in American rivers in the 1960s. In addition to the published findings, the toxicity
of this element, particularly its organic compounds, was brought to light by the
Environmental Science
Mercury Contaminated Sites (ed. by R. Ebingbaus et al.l
© Springer-Verlag Berlin Heidelberg 1999
After SOO Years of Mining and Smelting
v. MIKLAvCI<::
Due to mining and smelting processes, and due to the naturally increased contents of mercury in soil,
the wider surroundings of Idrija are contaminated with mercury. The Idrija ore deposit contains rocks
enriched with cinnabar originating from periods up to Middle Triassic. Native mercury can be found
primarily in Carboniferous clastic rocks which reach the surface in the western part of the ore deposit.
In the 1970S, when the production of mercury reached its peak, the first intensive studies of the
ecological cycle of mercury were made. New analytical techniques and improved methods for
determining the total mercury and methylmercury contents were introduced in order to study the
uptake and distribution of this element in the ground, air, water, plants, animals and man. After 20
years, systematic determinations of total mercury in environmental and biological samples were
started again. In our work, total mercury in air, lichens sampled in situ, transplanted lichens, carrots
and beans were determined, using gold amalgamation cold vapour atomic absorption spectrometry
(CV AAS) after acid decomposition under pressure, or in the case of air measurements, the double
amalgamation technique followed by CV AAS. Measured concentrations of total gaseous mercury in
air varied from 10 to 277 ng Hg m J. The total mercury contents in lichens sampled in situ were in the
interval between 3 to 23 fIg Hg g 1 dry sample (d.s.). The total mercury content in carrot ranges from
approximately 60 to 760 ng Hg g -I d.s. The concentrations of total mercury in beans were in the
interval between 2 to 23 ng Hg g-I d.s.
1
Introduction
The discovery of one of the world's largest mercury deposits in 1490 led to the
opening of the Idrija Mercury Mine, which, over a period of 500 years of
continuous operation, experienced exceptional technical, technological and
scientific development, which also left its mark on the town of Idrija. However,
500 years of mining activities produced harmful effects on the environment due
to pollution with mercury and, partly, ionizing radiation from radon and its
daughters. Over these 500 years, generations of Idrija miners extracted lO7000
tons of mercury (Hg) for commercial purposes. Taking into account all the
losses, which were particularly excessive in the early periods of extraction, it may
be estimated that the total quantity of extracted Hg surpassed 147000 tons.
The Idrija Mine operated successfully until the global Hg crisis in the 1970S. In
1969 the results of many years of research on the influence of Hg and its
compounds on the environment and humans were published in the United States
(Jensen and Jernelov 1969; Jernelov 1969). Large quantities of Hg had been found
in American rivers in the 1960s. In addition to the published findings, the toxicity
of this element, particularly its organic compounds, was brought to light by the
Environmental Science
Mercury Contaminated Sites (ed. by R. Ebingbaus et al.l
© Springer-Verlag Berlin Heidelberg 1999