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(77-07) Pesticide volatilization from bare soil: evaluation of the Theoretical Profile Shape Method. Ferrari, Federico*,1, Nicelli, Marco1, Trevisan, Marco1, Capri, Ettore1, 1 Istituto di Chimica Agraria ed Ambientale, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, Piacenza, Italy ABSTRACT- Volatilisation may represent an important factor influencing environmental fate of pesticides. Theoretical Profile Shape (TPS) is a versatile micrometeorological method used to evaluate volatilisation rate after pesticides distribution and is based on Trajectory Simulation Model, used to simulate movement of pesticides away from the treated field. Different environmental parameters (air and soil temperature, soil humidity, solar intensity) and physical-chemicals a.i. propriety influence volatilisation rate. Volatilisation rate of procymidone, malathion and ethoprophos in a field study lead in three different seasons (winter, spring and autumn) has been determined using TPS method. Experimental studies were carried out on a bare silty soil in Bologna province, Po valley area, Italy. Residues in the air were continuously determined per 2-3 weeks after the pesticide applications. Volatilisation rate was 15%, 5%, 11% in winter, 137%, 225%,176% in spring and 31%,14%, 20% in autumn of applied dose for procymidone, malathion and ethoprophos respectively . TPS Method results were overestimate in spring (over 100% for either a.i.) because of extreme meteorological conditions (such as high speed wind) during sampling period. Other available methods, including mathematical models, were compared to propose the validity of the TPS as a method for assessing the volatilisation rate of several pesticides in different environmental condition. Furthermore the factors influencing negatively the method of calculation were evaluated. Key words: tps, volatilisation, malathion, ethoprophos |
