Presented at the14th Meeting of the Group of European Charophytologists (GEC), Barcelona, Spain, 20-22 October 2006

Methods: PART TWOEFFICIENCY OF

PHYCOREMEDIATIONAt the scale of four selected ponds (MRA,

GRA, GRB and GRD pond, plotted and boxedon Fig.2c), detailed investigations over two lifecycles of the vegetation are undertaken.

••evaluate the transfer of metal ions from contaminated sludge to plants

••evaluate the loss of organic pollution by degradation

The present study is carried out as a doctoral thesis supported by the French Ministry of Research (CIFRE 0083/2005) and the Société des Autoroutes du Sud de la France (ASF)

CHAROPHYTES IN TECHNOTOPES, TOOLS FOR PHYCOREMEDIATIONThe ponds studied here represent a selection out of 1,600 motorway retention basins.

Under Mediterranean climate, these TECHNOTOPES (man-made biotopes for technological uses) are mostly temporary environments,being flooded in winter and drying out during several months in summer. The water depth varies from 0 to 1,00 m and can increase to 2,00m in case of exceptional floods. Although the sediments could be contaminated with both organic and inorganic pollutants, the Characeaedevelop large vegetation in terms of biomass in c. 72 % of these ponds (Fig.1). The objective of our study is to test the use of these algaeas tools to remove pollutants or to render them harmless - a process called PHYCOREMEDIATION sensu John (2003).

This investigation is part of a global project on road sludge aiming to work out techniques for extracting pollutants from sediments usingthe spontaneous vegetation of retention ponds in Mediterranean region (Fig.2a and b).

Time(months)

PPOONNDDoouuttffllooww

Environment

watershed area

• Active basin area• Land use & impervious cover• Rainfall area • Precipitation

climate

• Temperature

landscape• Land cover

• Hydraulic connection• Pond location

dryhydraulicconditions

dryweather