LOCAL AND REGIONAL DISTRIBUTION OF POPS IN MOUNTAIN ENVIRONMENTSEVALUATION OF BURDEN AND FLUXES IN BIOTIC AND ABIOTIC MATRICES

In this work some of the main factors that influence the partition and distribution of POPs in mountain environments and the behaviour of pollutants inside a pasture environment are evidenced. The variability of contamination at a local scale has been deeply analyzed in the main study area of the Andossi plateau, giving some useful information about the dependence of contamination from seasonality, soil and meteorological features. With the findings of chapter II (which gave a good definition of the horizontal, vertical and seasonal variability of contamination at local scale) and the modeling of chapter III it is possible to integrate a set of simple data (about OM content and soil temperatures) with concentration data from few samples to obtain detailed maps of potential contamination and release in a mountain environment. By knowing the local variability with a high definition it is possible to draw realistic pictures of concentration into complex alpine environments and evaluate exposure risk for the local fauna or for the domestic animals grazing on alpine pastures. In chapter IV it is reported the first field work about the different retention potential of humic substances. OM is generally considered in POPs distribution papers as a whole indistinct component of soil and its effect is only viewed as quantitative (general direct relationship between OM content and POPs concentration), but the different retention potential of humin, humic acids and fulvic acids may change this view. Moreover the three humic substances have different behaviour in terms of mobility and general ability to distribute vertically and horizontally within the soil affecting the transport of the pollutants adsorbed. In chapters V and VI the distribution into biotic matrices has been evaluated, evidencing a strict relation between soil and vegetation contamination (taking also into account local variability due to different solar exposition) and also a good relation between POPs concentration in vegetation and milk. Seasonality of contamination and grazing location could lead to different intake of contaminants by cows and so higher or lower milk contamination. The first POPs contamination data in the Mt.Meru area (Tanzania) have been reported in chapter VII and some of the findings about regional scale distribution factors have been confirmed in an equatorial area.