Soil
Soils representative of the Argentinean Pampa (association of
typical argiudols and udifluvent) were sampled from a soybean
field near La Dulce village in the Río Quequen Grande watershed (S
38 11.70 2900 W 59 08.80 3600). Surface soils had a total pesticide
level (endosulfan, DDTs, HCHs, heptachlors, dieldrin and chlordanes)
lower than 2 106 mg g1, and comprised 1.9% organic
carbon, 60.7% sand, 31.8% silt and 7.3% clay (Gonzalez et al., 2010).
The soil samples were air-dried until constant weight, ground to
obtain a homogeneous matrix and maintained at 4 C before conducting
the experiment. Each soil sample was spiked by adding
technical endosulfan (Master R, Chemiplant S.A. 35%) dissolved in
acetone to achieve a final concentration of 10 mg g1. After the
solvent evaporated, the spiked soil was shaken for 30 days until a
homogeneous distribution of pesticides was achieved. Then, the
sample was maintained for one week at room temperature
avoiding light effects or evaporation processes, before itwas used in
the phytoremediation experiments. The pesticide residues were
analyzed immediately before initiating the experiments to evaluate
the homogeneous distribution of the spiked soil.