In:
Journal of Environmental Quality, Wiley, Vol. 32, No. 4 ( 2003-07), p. 1183-1193
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 ( 14 C‐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 14 C‐organic compounds and 14 CO 2 separately, and the detection of soil residues allow for a mass balance of radioactivity of the 14 C‐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 μg 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.
Type of Medium:
Online Resource
ISSN:
0047-2425
,
1537-2537
DOI:
10.2134/jeq2003.1183
Language:
English
Publisher:
Wiley
Publication Date:
2003
detail.hit.zdb_id:
120525-0
detail.hit.zdb_id:
2050469-X
