Formulation approaches to reduce post-application pesticide volatilisation from glass surfaces

Michael Houbraken; David Senaeve; Edelbis López Dávila; Valens Habimana; Benny De Cauwer; Pieter Spanoghe

doi:10.1016/j.scitotenv.2018.03.186

Formulation approaches to reduce post-application pesticide volatilisation from glass surfaces

Sci Total Environ. 2018 Aug 15:633:728-737. doi: 10.1016/j.scitotenv.2018.03.186. Epub 2018 Mar 28.

Authors

Michael Houbraken¹, David Senaeve², Edelbis López Dávila², Valens Habimana², Benny De Cauwer³, Pieter Spanoghe²

Affiliations

¹ Laboratory of Crop Protection Chemistry, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium. Electronic address: Michael.houbraken@ugent.be.
² Laboratory of Crop Protection Chemistry, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
³ Weed Science Unit, Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.

PMID: 29602111
DOI: 10.1016/j.scitotenv.2018.03.186

Abstract

Volatilisation is one of the main pathways for pesticide emission to the atmosphere. While formulation strategies and adjuvants are known to affect the fate of active ingredient, no general volatilisation reducing guidelines exist for formulation purposes. Moreover, as limited information on formulation effects is available, current pesticide fate models lack parameters characterising reduction of active ingredient volatilisation. The objective of this study was to investigate the volatilisation reducing potential of formulation types and adjuvants, and to propose an effective vapour pressure for pesticide fate modelling. Several formulations of fenpropimorph, pyrimethanil and tebuconazole were produced and tested in a wind tunnel to evaluate the effect of formulation on active ingredient volatilisation. Produced emulsifiable concentrates with high volatile solvents did not offer any reduction in volatilisation, while the low volatile solvent reduced the volatilisation of pyrimethanil and fenpropimorph with 79.2 and 52.9%, respectively. The microemulsion reduced the volatilisation of fenpropimorph, pyrimethanil and tebuconazole with 57.6, 57.8 and 49.8%, respectively. High surfactant-active ingredient ratios (100:1) reduced the volatilisation of applied amount of pyrimethanil with 50%, on average. The effective vapour pressure of pyrimethanil formulated as a commercial available suspension concentrate was reduced by 33.8%. The commercial available emulsifiable concentrate did not reduce volatilisation of fenpropimorph. Effective vapour pressures of formulated fenpropimorph and pyrimethanil were determined and showed a high correlation with the amount volatilised within 48h. The saturated vapour pressure is useful when comparing the volatility of active ingredients, but effective vapour pressures are more appropriate to be used in pesticide fate models.

Keywords: Adjuvants; Formulation; Vapour pressure; Volatilisation modelling.