Rate of loss of insecticides during soil solarization and soil biosolarization.

This paper reports the use of solarization and biosolarization to decontaminate a soil polluted with six insecticides (buprofezin, pirimicarb, pirimiphos methyl, pyridaben, pyriproxyfen and tebufenpyrad). In the experiment, 17-L pots filled with clay-loam soil were placed in a greenhouse during the summer season and then contaminated with the insecticides of interest. Treatments consisted of different solarization and biosolarization treatments, including a control without disinfection. For both solarization and biosolarization treatments, low-density polyethylene film was used as cover; the biosolarization treatment involving application of a mixture of sheep and chicken manures at a rate of 400 g pot(-1). Five pots per treatment were sampled periodically up to 90 d after the beginning of each treatment. The results showed that both solarization and biosolarization enhanced the degradation rates of most of the insecticides tested compared with the control, probably as a result of the increased soil temperature. Pirimicarb, pirimiphos methyl, tebufenpyrad, pyriproxyfen and pyridaben were degraded to a greater extent in the biosolarization than in the solarization treatment. The results confirm that both solarization and biosolarization can be considered as a remediation tool for soils polluted by these insecticides.