Monitoring tricyclazole residues in rice paddy watersheds Laura Padovani, Ettore Capri * , Caterina Padovani, Edoardo Puglisi, Marco Trevisan Istituto di Chimica Agraria ed Ambientale, Universita ` Cattolica del Sacro Cuore, via Emilia Parmense 86, 29100 Piacenza, Italy Received 4 February 2005; received in revised form 26 April 2005; accepted 2 May 2005 Available online 5 July 2005 Abstract Pesticide application to rice paddies may affect the quality of environmental resources such as groundwater and sur- face water. The distribution of residues of tricyclazole, an environmentally persistent fungicide used widely in Italy, was monitored in the network of surface water bodies surrounding the main rice production area in Italy. The location of monitoring sites was based on the potential risk for contamination with tricyclazole. This was determined as a function of the area of rice grown, the geographical distribution of rice crops susceptible to the pest, and sales of tricyclazole. Monitoring sites were also located to represent different spatial scales (farm, catchment and basin). For water samples taken shortly after application in July and August, the highest concentrations of tricyclazole were measured at the farm sites. However, residues were also detected at the catchment and basin scale. The 95% of the measured residue levels was below 9.80, 1.20 and 1.15 lgl 1 , at the farm, catchment and basin scales, respectively. In sediment, tricyclazole residues were detected in 12 out 176 samples collected with the 95% of the measured residue levels below the concentration of 0.03 mg kg 1 . Residues were sporadically detected in samples taken after the crop was harvested in November and December. Variables such as the scale of sampling, the season and the year, were significant in determining pesticide residue distribution. The type of water body was less significant. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: Tricyclazole; Paddy rice; Surface water quality 1. Introduction Italy is the most important rice producing country in Europe, accounting for 660 000 of the 1 140 000 metric tons of milled rice produced by the European Commu- nity each year (Ente Nazionale Riso, 2004). Ninety-nine percent of rice grown in Italy is grown in Northern Italy on an area totaling 232 800 ha, located mainly along the basin of the Po River (Fig. 1). The area under culti- vation has increased rapidly due to the high profitability and the cultural and traditional relevance of this crop. Expansion has occurred even in areas traditionally less suitable for rice production, where the presence of irriga- tion water makes cultivation possible. Rice is grown mostly under flooded (paddy) conditions on a range of soils, where organic matter content can vary from 0.5% to 20% and where clay and sand contents can be greater than 50%. Groundwater ranges in depth from 0 to 50 m. Due to these properties, agronomic practices 0045-6535/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2005.05.025 Abbreviations: RI, rice index calculated for the commune or province; BI, BEAM Ò index calculated for the province; LOD, limit of detection. * Corresponding author. Tel.: +39 05 2359 9218; fax: +39 05 2359 9217. E-mail address: ettore.capri@unicatt.it (E. Capri). Chemosphere 62 (2006) 303–314 www.elsevier.com/locate/chemosphere