Groundwater fluorescence analysis in Southern Italian regions affected by desertification processes

Desertification is the degradation of land in arid, semi-arid, and dry sub-humid areas and it is primarily due to human activities and climatic variations. Nowadays, this matter does not refer only to the expansion of existing deserts but it occurs because dryland ecosystems are extremely vulnerable to climate changes, over-exploitation and inappropriate land use. In the Italian scenario, the impact of desertification is restricted to the southern regions where the risk is linked to water erosion, strong human aggressiveness, intense precipitations and to water and soil salinization. To this respect, the Italian project RIADE (Integrated Research for Applying new technologies and processes for combating DEsertification), has selected the area of Syracuse and the alluvial plain of the Licata town for an integrated application of the hydrogeochemical and spectroscopical methods in order to settle on qualitative characteristics of the water resources. Laser Induced Fluorescence (LIF) spectroscopy has been chosen for its intrinsic skills to be employed in real time water quality parameter determinations, with portable instruments during intensive monitoring campaigns. This technique allows to perform qualitative and quantitative in situ determination of dissolved (humic and fulvic acids, pollutants) or particulate (phytoplankton) organic matter. The ENEA laser remote sensing laboratory has designed and developed a new portable instrument, in order to match the requests of monitoring skills on relevance sites for RIADE. In the late Spring 2005 (May 22 – 25), a joint campaign has been performed in the Licata area (Sicily, Agrigento province), along the Salso river and in different wells in the neighbourhood territory. Distribution maps of the measured parameters as: a) dissolved matter, i.e. CDOM (Chromophoric Dissolved Organic Matter), tyrosine and tryptophan; b) particulate matter (algae); c) groundwater depth; d) electrical conductivity; e) pH; f): temperature; will be presented and discussed in term of emerging information on ongoing desertification processes.