A New Laboratory Protocol to Monitor the Volatilization of Pesticides from Soils

Abstract

A laboratory set-up is developed to measure the volatilization of pesticides from soils. It allows the simulation of field conditions and the control of all the parameters that can influence the volatilization phenomenon. These parameters consist of micro-climatic factors such as temperature, soil and air humidity, wind-speed, and also by physicochemical factors like the nature of pesticides and soil types. A preliminary study of the volatilization is conducted on lindane adsorbed on an Alsatian soil (France): the loess. The influence of soil moisture on the volatilization rate is assessed. Lindane appears to volatilize faster from a loess at field capacity (12.4% m/m of the dry soil) than from a dry loess. Indeed, 11% of the lindane initially adsorbed on the soil was volatilized after 26 days from the wet soil against only 0.8% from the dry soil during the same period. This difference is probably due to a soil-water extraction of the lindane adsorbed on the soil or to a competition between water and pesticide molecules for the adsorption sites on soil surfaces.