Phytoremediation in the proximity of a Copper Mining site of Chile using P. deltoides x P. petrowskyana hybrid, Salix babilonica L and shrub species.

1 Estefania Milla-Moreno, University of British Columbia

2 Robert D. Guy, University of British Columbia

Mining is by far the most productive business in Chile. Nowadays Chile has about 603 mining tails and holds the biggest deposit of toxic waste in Latin America, the "El Mauro" tailing damp. Whenever a tailing pond wall collapses the heavy metals and chemical materials captive in them are rapidly released contaminating rivers and creeks in the surrounding region. For this reason it is mandatory to develop research that incorporates sustainable solutions for mining closures, ensuring safety for local communities and ecosystems.

The proposed research can help develop soil and water recovery strategies for sites next to mining tails through 'Phytoremediation'. This biotechnology uses plants and their associated microbes to remove pollutants promoting environmental clean up for in situ soil remediation. There is evidence that poplar and willow species may be great candidates for phytoremediation. A polyculture of P. deltoides x P. petrowskyana hybrid, Salix babilonica L., Lomatia dentata, Olea europaea L., Ricinus communis L., Schinus polygamous L. and Prosopis chilensis (Molina) Stuntz is chosen to investigate the tolerance limits of these species in a glasshouse Rhizofiltration experiment and a Phytoextraction field experiment under heavy metal contaminated substrates. In both experimental settings the following physiological traits will be monitored: photosynthesis, chlorophyll fluorescence, nitrogen content, leaf mass area, and water use efficiency along with some anatomical traits such as stomatal behaviour, thicknesses of palisade, spongy mesophyll and cell wall, mesophyll surface area exposed to intercellular air space per leaf area and lastly heavy metal detoxification. This research aims to solve the following hypothesis: 1) The amount of volatile pollutants concentrated on the leaf blades is directly linked to the plant productivity and leaf macro anatomy, 2) Leaves with higher LMA will sequester higher amounts of heavy metals and will have higher photosynthetic rates given the greater cell wall area for CO2 diffusion to chloroplasts, 3) Heavy metal tolerance and microbial rhizosphere flora are directly related.