MODELLING THE ENVIRONMENTAL IMPACT OF PESTICIDES SPRAYED ON GREENHOUSE TOMATOES: A REGIONAL CASE STUDY IN COLOMBIA

In many horticultural areas, the pest management in bio-physically limited and technically constrained production systems is reduced to a chemical control strategy. The environmental impact and fate of pesticides and fertilizers is becoming a matter of growing concern among research organizations and governmental institutions in countries such as Colombia. The objective of the present work was to estimate the environmental impact caused by the pesticides used in greenhouse tomatoes. Primary information was collected through structured interviews with a representative set of local growers. For each grower amount of pesticide products used as well as the pesticide management schemes were investigated. Through a life cycle assessment approach the environmental impact of pesticides manufacture, transport and field use was estimated. An adapted version of the PestLCI and USES-LCA models were used to estimate the environmental fate of pesticides for each individual production unit. The USES-LCA model considered the field use stage with the topsoil layer and the air as the affected environmental compartments. Afterwards, the impact was scaled-up to the regional level by modelling the spatially variability observed for the surveyed pesticide data. In order to determine if the environmental impact caused by pesticides is evenly distributed or exhibited any spatial pattern a point pattern analysis was carried out. Results indicated a higher impact at the manufacture stage for most of the categories analysed. A high variability on the environmental impact was observed at the regional scale due to the different products and schemes applied by individual growers in the region.