IWRA Proceedings

AbstractRainwater chemistry was monitored during a two years period (Nov. 2003 – Oct. 2005) for quantification of the atmospheric input over a small (70 km2) rural Mediterranean watershed. A refrigerated wet-only precipitation collector with a nearby bulk sampler were installed at one station. Two more bulk samplers were installed, near the top of the basin and close to the basin outlet. Major element contents (HCO3, Cl, NO3, SO4, Ca, Mg, Na, and K) were determined by Ion Chromatography, nutrients content (PO43-, NO3- ,NO2- and NH4+) determined following APHA standard and trace element contents (Al, B, Ba, Cd, Cr, Cu, Co, Li, Mn, Mo, Ni, Pb, Rb, Sr, U, V and Zn) by ICP-MS. During the observation period, a total of 83 rain samples were collected and analyzed for wet and dry deposits determination. The dataset obtained from the field study is presented and discussed. The primary objectives were i) to compare wet and bulk deposition, ii) to evaluate the temporal and spatial variation in rainwater for contaminants, and iii) to estimate the annual atmospheric input to the basin, derived from natural or anthropogenic origins and to identify potential pollution from rain. Finally, the possible origins and the main factors affecting the concentrations of the measured species are discussed. The estimation of the precipitation inputs is a part of the diagnostic study of the chemical and microbiological fluxes contribution of the watershed to the Thau lagoon.