QUALITY AND CONTAMINATION OF AGRICULTURAL SOILS IN HUNGARY AS INDICATED BY ENVIRONMENTAL MONITORING AND RISK ASSESSMENT

摘要

This paper attempts to summarise the concepts that are relevant for characterisation of the environmental status of our soils at present as well as in the long-term. Environmental Monitoring detects changes in soils and characterises their quality. The Soil Fertility Monitoring System of Hungary focuses attention on changeable soil characteristics and this monitoring program clearly proved that soil acidification is one of the most significant degradation processes in Hungary. Moreover, the degradation of soil quality by acidification was clearly related to the decline of the soil fertility function, that is the yield as well as the NPK fertiliser efficiency decreased. The Soil Information and Monitoring System characterises the chemical, physical and biological status of soils in Hungary. Studying the heavy metal contents of this complex database it can be concluded that the soil cover of Hungary is not polluted by heavy metals, but a small minority of soil samples do represent polluted sites. Environmental Risk Assessment takes into consideration the effects of pollution loads. The environmental risk is quantified by the Risk Quotient, which is equal to the ratio of the Predicted Environmental Concentration (PEC) and the Predicted No Effect Concentration (PNEC). Large Risk Quotients were determined in contaminated soils. Environmental Risk Assessment and Environmental Monitoring were compared in detail. Based on their advantages and limitations it was concluded that their appropriate integration is the best solution for characterising the state of our environment and predicting trends and changes. The accumulation of toxic contaminants in soils may become a Chemical Time Bomb in the long run. The extent of the chemical contamination can be characterised either by the Polluting Concentration (= Measured Concentration - PNEC) or by the Toxic Unit (= Measured Concentration / PNEC). The Capacity Controlling Parameters determine the behaviour of accumulated contaminants in the short-term as well as in the long-term. The factors and processes determining Soil Quality were reviewed because of the continuous pollution of soils. Soil Quality can be characterised by a soil chemical approach, where solid phase composition is fundamental and this together with the solution composition and kinetics determine the chemical behaviour of soils, including that of contaminants. Soil Quality can also be described by a soil biological approach, where the composition of the community is the basis and this together with activities and biological cycles determine the microbiological behaviour of our soils. It was concluded that soil chemistry and soil microbiology determine the Soil Quality together and their integrated use is an appropriate key for characterising the state of our soils in the long-term.