Bio-phytoremediation of organic pollutants in soils from organic farms: current situation in Poland and challenges

Contamination of soils with persistent organic pollutants (POPs), particularly DDT, is very common in the natural environment, and their removal from the soil has become a serious problem. Results of a monitoring program showed that about 30% of the soil samples collected from eight Voivodeships contained DDT residues. We have thus started a research program aiming at: (i) assessing the presence of DDT contamination in different Polish soils; (ii) evaluate the risk of DDT contamination for different horticultural crops; (ii) evaluating the efficacy of different crops for phytoremediation; (iii) isolating and selecting soil microbial organisms able to metabolize DDT; (iv) assess the efficacy of a bio-rhizoremediation method to reduce the soil contamination with DDT. The consortia utilized in the bioremediation trials showed to favor DDT uptake by the plants and its translocation to above ground organs. Cucurbita pepo L. resulted the most efficient in DDT uptake. A rhizoremediation strategy, using C. pepo plants inoculated with specific microbial strains, seems to better sustain the uptake and accumulation by plants of DDT residues reducing the risk of residue presence in food.