264
V. Miklavi:ii:
Fig. 2. Map showing the locations of the sampling areas of carrot and bean and the m erc ury sources
3
Results and Discussion
In the year 1992, 76 measurements of total gaseous Hg in air were performed at
one location outside our laboratory (located close to the Idrija centre), three
parallel samples for measurement (Lupsina et al. 1992). The duration of sampling
was adapted to the weather conditions. Most of the measurements involved
momentary concentrations of Hg in air, which means that the sampling period
lasted a few hours at maximum. The air intake ranged from 10 to 60 I h - I. Thus,
the smallest and the largest volumes of air samples were 0.03 m 3 and 0.1 m 3 ,
respectively.
The values of Hg concentrations in air obtained varied significantly, the lowest
being 10 ng Hg m- 3 (19 October 1992) and the highest 277 ng Hg m- 3 (28 August
1992). The results of previous measurements of momentary Hg concentrations in
air conducted in a natural environment have shown that Hg concentrations
increase with increasing external air temperature, while wind reduces Hg
concentration markedly, as is evident in Fig. 3.