Zs. P. Komáromy szerk.: Studia Botanica Hungarica 16. 1982 (Budapest, 1982)

Hably, Lilla: The relation between Pb-pollution along mainroads and the trace element-composition in soil and vegetation (Examination of section rectangular to M3 mainroad)

3.6. The examination of areal variations of soluble trace element content So far the vertical changes within the section and of the soluble trace element content, their relations have been examined. With view to the whole area calculations have been made with the aim of examining whether there is a linear connection between the soluble element content of the different elements within the same soil level of different places. The basis for these calculations was the previously designated A, respectively B, and C levels. The average of the elements of the different levels were separately calculated (Table 6.) and further the correlation between the soluble element contents of the different levels were calculated with regard to these. The values thus obtained are shown in Table 8. It is to be seen that there is hardly any correlation within level A. With Mn and Pb the values are somewhat higher, but do not reach the criterion of correlation. The situation is similar in level B. It is Mn and Pb as well as Cu and Pb which show very low positive correlation, but these values are so little that strictly speaking they cannot be accepted as correlation. Only in level C do we find closer positive correlation between Mn-Cu, Mn-Pb, Cu-Pb. The connection between soluble element content and pH was examined also here. For the new arrangement the data to be calculated had to be standardized anew. The standardized data are contained in Table 7., the correlation values in Table 8. No element in level A shows any horizontal connection with the change in pH. This applies to level B, as well. In level C only Mn shows acceptable negative correlation with pH while with the other elements this value is too small to be acceptable. It was previously seen that pH shows significant connection with almost all the elements within the sections, i.e. vertically. This is why it is surprising that horizontally just the opposite is shown. An explanation of these results will be given in the "Conclusion". 4. The chemical reaction of soils The analysis of the chemical reaction of the soils proved to be of basic significance in making decisions about all the problems. By means of pH-analysis of samples it was possible to draw general conclusions as to the chemical reaction of the soils in the area; at the same time careful observation of pH-changes made it possible to draw futher conclusions concerning the area. The pH values measured in the sections analysed range between 5,25 and 8.5. Analysing the areal variations of values, it was remarkable that while in some places alkaline values of almost 8 pH can be found already between 0 and 20 cm, in other places pH is 5.25 in the some depth. The sampling places are not so far away from each other, that such great difference should exist between the pH-s of levels of the same depths. It can be seen most distinctly in the pH-diagram of Section No.

38 (Fig. 9) that from mildly acidic pH it changes gradually into more acidic, then it becomes weak again moving into alkalescent interval, then its alkalinity grows gradually again. After that close observation of the rest of the sections shows similar regularity. Sections No. 37 (Fig. 8) and No.

34 (Fig. 6) are incomplete, but both show this tendency, especially No. 34 in which pH produces even alkaline chemical reaction. Sections No. 32 (Fig. 4), No. 33 (Fig. 5) also show the same regularity although at different vertical levels. Sections No. 30 and 31 have only alkaline parts. Arranging our samples in linear order: No. 34, 33, 32, 31, 30, road, 36, 37, 38; the following can be observed: The upper layer of section No. 34 is alkaline, with 5.25 pH at the beginning and changes from acidic into alkaline at the depth of 80 cm. Section No. 33 has pH = 6 as a starting point which at the previous one was between 20 and 40 cm. The unequivocal change from acidic into alkaline pH also occurs 20 cm deeper than in the previous section, i.e. at the depth of 100 cm. There is a significant difference between section No. 32 and No. 33. Section No. 31 has its starting point already in alkaline interval. As compared to section No. 34 the position similar to the above is obtained with a shift of 80 cm. Section No. 30 has to be shifted by 20 cm in relation to 31, and by 100 cm in relation to the starting 34 in order that their pH-s should be the same. The opposite side of the road offers the same situation. It can be clearly observed that 37 has to be shifted by 60 cm in relation to 38, 36 has to be lowered by 130 cm. In Fig. 10