Technical Note Solarization and biosolarization enhance fungicide dissipation in the soil José Fenoll a, * , Encarnación Ruiz a , Pilar Hellín a , Simón Navarro b , Pilar Flores a a Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario, IMIDA, C/Mayor s/n, La Alberca, 30150 Murcia, Spain b Departamento de Química Agrícola, Geología y Edafología, Facultad de Química, Universidad de Murcia, Campus Universitario de Espinardo, 30100 Murcia, Spain article info Article history: Received 26 October 2009 Received in revised form 18 January 2010 Accepted 20 January 2010 Available online 10 February 2010 Keywords: Fungicide disappearance Soil decontamination Solar heating Mulching Biofumigation abstract Although there is some evidence regarding the effect of solarization and biosolarization on pesticide deg- radation, information is still scarce. The aim of this study was to determine the effect of these disinfection techniques on the degradation of eight fungicides (azoxystrobin, kresoxin methyl, tebuconazole, hexac- onazole, triadimenol, cyprodinil, pyrimethanil and fludioxonil) commonly used in pepper crops under greenhouse cultivation. Seventy-five 17-L pots filled with clay-loam soil were placed in a greenhouse during the summer season and then contaminated with the studied fungicides. Treatments consisted of different disinfection treatments, including a control without disinfection, solarization and biosolariza- tion. For the solarization and biosolarization treatments, low-density polyethylene film was used as cover. Five pots per treatment were sampled periodically up to 90 d after the beginning of each treatment and fungicide residues were analyzed by GC/MS. The results showed that both solarization and biosolar- ization enhanced fungicide dissipation rates with regard to the control treatment, an effect which was attributed to the increased soil temperature. Most of the fungicides studied showed similar behavior under solarization and biosolarization conditions. However, triadimenol was degraded to a greater extent in the biosolarization than in the solarization treatment, while fludioxonil behaved in the opposite way. The results confirm that both solarization and biosolarization contribute to pesticide dissipation and can therefore be considered alongside other soil disinfection techniques, as a bioremediation tool for pesti- cide-polluted soils. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction The prohibition of methyl bromide for agricultural use has meant that growers have had to adopt disinfection techniques that are more respectful of the environment. In this respect, solarization and biofumigation are currently used in the province of Murcia (southeast Spain) as soil disinfection techniques for greenhouse pepper crops (Ros et al., 2008). Solarization is based on solar heat- ing of the soil by mulching with transparent polyethylene during the hot season (Katan and DeVay, 1991), while biofumigation is based on the use of gasses resulting from the decomposition of or- ganic matter (De León et al., 2001; Matthiessen and Kirkegaard, 2006). To enhance the beneficial effect of biofumigation, it is usu- ally combined with solarization. This combination of biofumiga- tion and solarization is referred to as biosolarization by some authors (Flores et al., 2008; Ros et al., 2008). Both solarization and biosolarization have produced good results, especially in low-input and organic farming systems. On the other hand, fungicides are widely applied to protect plants from infections and diseases, thus enhancing the production and quality of food crops. However, a fraction of the amount used may reach the soil and lead to soil pollution. The fate of fungicides in soil is governed by processes that affect their persistence, such as chemical and microbial degradation, and processes that affect mobility, which involve adsorption, diffusion, absorption by plants, runoff, wind erosion, volatilization, leaching and assimilation by microorganisms. Adsorption process is essential in the fate of pes- ticide in soils. The most common quantitative measurement of the sorption of organic pollutants by soils from aqueous solution is the K OC . Thus, compounds with higher K OC values will be less mobile than those with lower values (Navarro et al., 2009). Soil solarization has been shown to affect the accumulation and dissipation of soil contaminants, so that pesticide persistence is either extended or shortened by solarization, depending on the nature and time of application of the pesticide (Rubin and Benja- min, 1983; Avidov et al., 1985; Yarden et al., 1989). In addition, the application of organic amendment to the soil may have an ef- fect on the degradation of soil pollutants. However, research inves- tigating the effect of biosolarization on the accumulation and dissipation of soil contaminants is still limited (Flores et al., 2008). The main objective of this study was to ascertain the effect of solarization and biosolarization, on the rate of loss of eight fungi- cides (azoxystrobin, kresoxim-methyl, tebuconazole, hexaconaz- ole, triadimenol, cyprodinil, pyrimethanil and fludioxonil) commonly used in pepper cultivation in Spain. The experiment 0045-6535/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2010.01.034 * Corresponding author. Tel.: +34 968366798; fax: +34 968366792. E-mail address: jose.fenoll@carm.es (J. Fenoll). Chemosphere 79 (2010) 216–220 Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere