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)

Section No. 36 (Fig. 7) As opposed to previous values an increase of A-level can be observed from 0 to 40 cm. Thus B-level decreases between 40 and 100 cm. Under this C-level reaches to the bottom of the section. pH is in the neutral-alkalescent and is within very small interval: 7.5-8. The change of the organic material content is very even. It gradually decreases from its maximum in the level (4.1%) to a minimum of 1.8%, which it reaches in the lowest 40 cm. Illite shows rather even increase with occasional minor regressions. It reaches its maximum in the lowest 20 cm of the section. The CaCG^-content of the soil is within a narrow, 1-7% interval thus it can be regarded rather constant. It is rather from C-level onwards that higher values can be found. In the relation to the element contcentrations, two generally even decreases can be observed here. Mn - which, as compared to the other elements, occurs in greater quantities also here - is on the whole constant in the upper 100 cm, reaches its maximum between 100 and 120 cm. After that it shows a rapid decrease to the bottom of the section. Lead - after its decrease in A-level -, similarly to manganese is enriched again between 100 and 120 cm, then shows a greater decrease than previously to the bottom of the section. The changes in the quantities of soluble copper and zinc are noteworthy. In A-level Zn is present in considerably larger quantities than before, exceeding copper, which is present in its usual quantity (around 5 ppm). Copper is relatively constant in the upper 120 cm, then shows gradual decrease. Zinc shows much greater extremes. After its 9.8 ppm in A-level, it greatly decreases then with its considerable decrease at 40 and 60 cm it remains at its usual level under 1 ppm to the end of the section. Section No.

37 (Fig. 8) This is a thin section only 60 cm deep. Its A-level is thick, 40 cm beneath that only 20 cm of B-level have been revealed. pH is neutral, mildly acidic. The organic material content shows rapid decrease downwards from its five weight per cent maximum in the upper most 20 cm. At the top Illite is about 17%, then its quantity significantly increases (25%), and later it decreases again. No carbonate was found in the examined depth of 60 cm. The change of Mn, Zn, Cu, Pb in the section is very even; downwards each decreases in about the same proportion. However, the quantities of Mn and Cu completely change places in relation to the first sections, thus the order will be Mn))) Pb) Zn) Cu. Section No. 38 (Fig. 9) A-level, similarly tot he first sections here, too, is 20 cm. B-level reaches until 120 cm, where C-level starts. Chemical reaction here yields one of the most beautiful changes. With the neutral pH acting as axle the change produces an S curve. Chemical reaction gradually grows from mildly acidic pH to the acidic. It reaches its acid maximum between 40 and 60 cm. After that it evenly decreases towards the neutral interval. The change from acidic to alkaline reaction occurs at 120 cm. From here on, it gets always more and more alkaline till it reaches 8.3 pH maximum at the bottom of the section. The organic material content culminates not in the highest level but between 40 and 60 cm. After that it shows an even decrease, remaining approximately constant under 120 cm. Illite is present in the upper section of the section in more or less the same small quantity. It increases at 100 cm, then it decreases reaching its maximum (about 40%), in the lowest 20 cm (180-200 cm). The section is free of carbonate to a depth of 140 cm. Carbonate appears here, then gradually increases to the bottom of the section, but its quantity hardly exceeds 4%. The changes in trace element content occur differently from those in the previous sections. It was shown earlier (30, 31, 36 sections), that at maximum element concentrations of 0-20 cm an outstanding value appears in the lower levels, which produces maximum of at least approximately maximum values. Here the level of 40-60 cm, is the zone containing the highest soluble concentrations. From here the trace element content of the rest of the levels shows almost symmentrical values in Cu and Pb change places between 80 and 120 cm. Zn appears in the lower 80 cm with its usual small concentration. Cu after its maximum shows the usual gradual decrease. This explains also the fact that between 80 and 120 cm it "precedes" lead since this shows a rapid decrease after a depth of 80 cm. both directions. The order Unlike in previous cases