Physicochemical characterization of sediments from two retention/ infiltration ponds: Wissous (Urban) and Ronchin (road)

The objective of this research effort is to derive a global and in-depth characterization of the organic and mineral matter of sediments from the Wissous and Ronchin retention and infiltration ponds. The mineral fraction of sediments from urban and road retention and infiltration ponds has been studied using a range of chemical and physical analytical methods; results show that the sediments are often polluted, with concentrations exceeding the reference values for polluted soils. A study of the organic fraction indicates that the various lipid fractions are basically composed of hydrocarbons, which include in particular polycyclic aromatic hydrocarbons (PAH) at high concentration levels. The PAH stem for the most part from pyrolytic combustion (wood, coal, diesel engine exhaust, etc.), whereas the linear and polycyclic hydrocarbons are generated from diesel vehicle motor oil and fuel. The mobility of trace metals has also been assessed using the sequential extraction diagram issued by the Community Reference Bureau, which enables ranking, by increasing order of mobility, the metals found in the environment as follows: Cr &le Ni < Pb &leCu < Zn &le Cd.