1. THE ROLE OF ORGANIC MATTER CONTENT OF SOILS IN THE ACCUMULATION OF POLLUTION IN A FOREST ECOSYSTEM Edit Hoyk Kecskemét College, Institute of Environment Science e-mail: hoyk.edit@kfk.kefo.hu

2. On western part of Mecsek Mountain that is covered by forest a protected landscape is being established :

3. Geological map of the area

4. Soil types of the area

5. Connection between bedrock and soil type

6. Objectives to evaluate the area’s behaviour towards pollutions and buffer capacity, correlate with organic matter content of soils The area is close to potential pollution sources (Pécs, Komló). Despite this, our supposition was: the area is less polluted. to verify that the area is in near-natural condition to justify that the projected Protected Landscape in Western Mecsek is worth to be protected

7. Methods soil samples were gathered all together from 72 sample sites within the area samples were collected from two sampling depths (5-10 cm and 30-40 cm) we aimed to cover the area systematically, fitting to the morphology beside the examination of organic matter content, we investigated other physical-chemical attributes and characteristics of the soils (cohesiveness, chemical reaction, carbonate content, vegetation, anthropogenic influence, heavy metal content etc.) the method for determining the organic matter content of the soils was the potassium dichromate oxidation with spectrophotometer measuring

8. Sample sites of the projected Protected Landscape in Western Mecsek

9. Results Forest soils (brown forest soil with clay washed in; Ramann brown soil; pseudogley brown forest soil; strongly acid, non-podsolic brown forest soil and rendzina) of Mecsek Mountain – due to its natural soil characteristics - are featured with high organic matter content: in near-surface samples the average amount of organic matter content is between 5-7 %, however in some cases it grows to 15-20 %, or even above 20 % (samples from gorges)

10. the organic matter content of samples from 30- 40 cm depth is 2-4 % in average the samples that can be characterised with heavy metal content slightly higher than the limit values, have 10-20 %, or occasionally more than 20 % organic matter content the connection between the organic matter content and metal content of the soils is strongest in the case of lead (R=0.64) and zinc (R=0.45):

11. Connection between Pb and organic matter content of soil samples (R=0.64)

12. Connection between Zn and organic matter content of soil samples (R=0.45)

13. Conclusions The examined soils can be characterised with high organic matter content that has an effect towards metal adsorption. According to the speciality of decomposition the organic matter content of soils originating from near-surface exceeds the organic matter content of the deeper soil samples. The samples with more than 20 % organic matter content have metal content that is in some cases slightly higher than the average.

14. This feature can be traced the most in case of zinc, which - beside lead - is in the tightest relation with the organic matter content. The high organic matter content provides appropriate conditions for the localization of the possible pollutions even beside acid chemical reaction. On the area examined the high organic matter content promotes the adsorption of metals that may imply the extraction of the possible contamination from the food chain.

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