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)

level of section No. 34, 106 m from the road, belongs to the enrichment zone, pH = 5.5. As already mentioned with lead, this is one of the main enrichment levels, while the pH = 6 zone has less significance from the point of view of Pb. Thus the examination shows that where lead enrichment takes place in the soil, the same occurs in the vegetation living on it. This explains why the Pb-concentration of maize can rise again at a great distance from the road. It can be concluded that plants take up Pb not only from the air but also from the soil; their lead concentration depends not only cm distance from the road, but also on the geochemical characteristics of the soil. Summary of the results obtained in course of the investigation 1. The primary effect of the road is manifested in the alkalescence of the pH of the soil, which can be detected down to a depth of 60-140 cm and to a distance of almost 100 m on both sides. 2. The enrichment-levels of the soluble trace element content (Mn, Cu, Pb) depend on pH, accompany the pH changing under the influence of the road to some extent independently of depth. 3. The soluble Zn-content depends on organic material content and is connected with the organic material and not with the pH. 4. The alkaline pH arising under the influence of the road causes subsequent carbonate production. 5. The most important enrichment levels of the soluble lead content shift towards the more alkaline and the more acidic pH of a given environment. 6. The Pb-content of the soil in the vicinity of the road does not show linear decrease in proportion to depth and to distance from the road. 7. In identical organs of different species and the different organs of the same individuum, the identical trace elements and so lead, too, accumulate in different measures. 8. The Pb-content of plants does not decrease in linear proportion with the distance from the road. According to geochemical characteristics (element enrichment levels), the value of Pb can increase even farther away from the road. 9. Plants take in lead not only from air, but also from the soluble Pb-content of the soil. 10. The Pb, Mn, Cu content of plants can not be directly related to the upper level of the soil.