Characteristics of dust particles abraded from pesticide treated seeds: 1. Size distribution using different measuring techniques

Abstract

All particle sizing techniques have their (dis)advantages and none of them is able to perfectly describe the real size distribution of non-spherical particles. The particle size information gathered can be used in dust drift prediction models, risk assessment tools and will help to better understand the dust drift phenomenon. © 2017 Society of Chemical Industry.

Comparing different techniques to assess the risk of dust drift from pesticide‐coated seeds

“…In contrast to wheat dust, the AI mass percentage of maize dust increases over time from 30.0 up to 59.0%. The dose at which the AIs are applied during the seed treatment explains the important differences between AI mass percentages in wheat and maize . The above findings were also observed visually (supporting information Fig.…”

“…To avoid swelling and dissolving of particles, sunflower oil – a very non‐polar solvent – was used as measuring liquid. This approach had been used before to gather particle size characteristics of dust generated with mechanical sieving, and a good agreement between laser diffraction and other particle sizing techniques was found …”

“…wild flowers, hedges and water bodies close to the field border), bigger particles could also have an important impact. Although the mass percentage of AIs in these particles is much lower than in smaller particles, contamination of one bigger particle in, for example, a bee bread or a waterbody could have a greater effect than several smaller particles. This is illustrated by an example for particles abraded from maize seeds coated with methiocarb (Table ).…”

“…In the authors' opinion, a good risk assessment can only be made if not only the total amount of abraded particles is known but also the size distribution, envelope density and ideally the chemical content . None of the techniques tested in this paper gives an idea of these physicochemical properties, but sieving and the individual sowing element allow for the collection of particles abraded by physically stressed seeds.…”

“…In this paper, two alternative measuring set‐ups to assess the drift potential of coated seeds are proposed and compared with the Heubach method: the mechanical sieving set‐up and the individual sowing element set‐up. Both methods were primarily used to generate dust for further physicochemical characterisation . This is the main reason why a commercially available alternative technique, the Satec Dust Monitor, was not tested.…”