PT13 Global Fate of POPs
Exhibit Hall
8:00 AM - Tuesday, 11 November 2003
(PT208) Polychlorinated Biphenyls (PCBs) and DDTs in Forests Along an Altitudinal Gradient.
Di Guardo, A1, Nizzetto, L1, Cerabolini, B1, Dilernia, R1, Gramatica, P1, 1 DBSF - University of Insubria, Varese, VA, Italy
ABSTRACT- Some POPs, (persistent organic pollutants) such as Polychlorinated Biphenyls (PCBs) and DDTs, are characterized by an elevated persistence and mobility potentially affecting all environmental compartments at a variety of spatial scales. Models were developed to understand their fate in the environment and initially they comprise only basic compartments such as air, soil, water and sediments as part of the model scenarios, while more recently the focus shifted on the role of forests in influencing the transport of pollutant from air to soil and viceversa. Vegetable biomass appear as a key factor for determining levels in soil, and consequently the exposure of terrestrial trophic chains. For example, forest soils generally present levels of POPs 2-3 times higher than agricultural soils. This phenomenon was related to the ability of leaves to accumulate organic pollutants, and consequently to transfer them to soil ("Forest Filter Effect"). In regional scale the question becomes of primary interest for environmental modeling, considering that in some geographical contests forests cover a conspicuous amount of the land surface. However, scarce information is available about POPs fate in forests situated at different altitudes. This work presents results on the distribution of PCBs and DDTs in leaves, litter and soil of three different forest types in the Italian Alps along an altitudinal gradient, showing different accumulation trends for broadleaves and coniferous, and different contaminants profiles between different vegetable associations. Moreover an evaluation of the "filter effect" has been carried on comparing levels between forested soils and bared soils at the same altitudes
Key words: Forest Filter effect, POPs, Soils, Altitude