Pesticide Volatilization from Soil

Abstract

A comparison was drawn between model predictions and experimentally determined volatilization rates to evaluate the volatilization approaches of European registration models. Volatilization rates of pesticides (14C-labeled parathion-methyl, fenpropimorph, and terbuthylazine and nonlabeled chlorpyrifos) were determined in a wind-tunnel experiment after simultaneous soil surface application on Gleyic Cambisol. Both continuous air sampling, which quantifies volatile losses of 14C-organic compounds and 14CO2 separately, and the detection of soil residues allow for a mass balance of radioactivity of the 14C-labeled pesticides. Recoveries were found to be > 94% of the applied radioactivity. The following descending order of cumulative volatilization was observed: chlorpyrifos > parathion-methyl > terbuthylazine > fenpropimorph. Due to its high air-water partitioning coefficient, nonlabeled chlorpyrifos was found to have the highest cumulative volatilization (44.4%) over the course of the experiment. Volatilization flux rates were measured up to 993 microg m(-2) h(-1) during the first hours after application. Parameterization of the Pesticide Emission Assessment at Regional and Local Scales (PEARL) model and the Pesticide Leaching Model (PELMO) was performed to mirror the experimental boundary conditions. In general, model predictions deviated markedly from measured volatilization rates and showed limitations of current volatilization models, such as the uppermost compartment thickness, making an enormous influence on predicted volatilization losses. Experimental findings revealed soil moisture to be an important factor influencing volatilization from soil, yet its influence was not reflected by the model calculations. Future versions of PEARL and PELMO ought to include improved descriptions of aerodynamic resistances and soil moisture dependent soil-air partitioning coefficients.

Notice of Retraction: Diesel oil volatile loss and the moisture content of soil during drying

“…The volatilization kinetics of the fungicide fenpropimorph expresses a clear corre lation between volatilization mtes and soil moisture content. Volatilization mtes reached a maximum 24hr 978-1-4244-7388-5/10/$26.00 ©201O IEEE 347 after application under moist conditions and decreased with the decrease in soil moisture over following days [9]. Li studied the effect of moisture content on the volatilization of diesel oil in soils.…”

How does exposure to pesticides vary in space and time for residents living near to treated orchards?

“…It incorporates the effect of prevailing meteorological conditions on the initial estimation of pesticide volatilisation from crops in the field. PELMO estimates volatilisation from soil water by assuming negligibly low concentration of pesticide in the air above the soil (not including soil-air partitioning) (Wolters et al 2003). Other competing processes for dissipation of pesticides in different environmental compartments were not included in our calculations so that leaching, transformation and wash-off from plant surfaces were all excluded, creating a more protective risk assessment.…”

“…Algorithms from PELMO were used in the estimation of pesticide emission rates from exposed soil surfaces on a daily basis (Wolters et al 2003; Ferrari et al 2005): …”

Heterogeneous reaction of particulate chlorpyrifos with NO 3 radicals: Products, pathways, and kinetics

“…Extensive researches have been conducted on the chlorpyrifos' detection methods, toxic effects [1], transformation, and degradation processes of chlorpyrifos in water and soil [9,10]. It was reported that atmosphere is a major receptacle and transport medium for pesticides through their spraying, volatilization, or wind erosion of soil particles and dusts which are loaded with pesticides [11][12][13][14][15][16]. Chlorpyrifos is a potential long-range transport pesticide in the atmosphere [17].…”