Assessment of the abrasion potential of pesticide-treated seeds using the Heubach test

Abstract

During sowing of pesticide-treated seeds, pesticide-laden dust and abraded seed particles may be emitted to the environment, possibly leading to environmental contamination and posing health risks. In many countries there is currently no legislation concerning the acceptable amount of dust of treated seeds. This study aimed to gain insight in the abrasion potential of available pesticide-treated seeds and its associated factors. The abrasion potential of 45 seed samples of 7 different species (viz. sugar beet, oat, barley, wheat, spelt, pea, and maize) was determined using the Heubach test and amounts of dust were expressed as g 100 kgseeds −1, g 100,000 seeds−1, and g ha−1. The abrasion potential fell generally within the boundaries of maximum permissible values adopted by different countries. Species, seed treatment company, number of active ingredient (AIs) and combination of AIs had significant effects on the abrasion potential, whereas little or no effect of agitation and conservation was found. However, species were situated differently with respect to each other depending on the unit in which the abrasion potential was expressed. A standard unit that takes into account the species’ seed rate is suggested to give the fairest assessment of dust drift risk and would allow international comparison.

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

“…As argued before in our review paper, the air velocity in the Heubach glass cylinder is much lower than that observed in field conditions, and a substantial amount of the coarser dust fraction is deposited there and therefore not considered in the Heubach measurement. According to Biocca et al ., the coarse dust fraction deposited in the glass cylinder of the Heubach dust meter could be 5.3–12.6 times higher than the fine fraction collected by the filter …”

“…As the Heubach test is internationally recognised as the reference technique to assess the abrasion potential of seed batches, we assessed 45 seed samples of different species to gain insight into the abrasion potential of pesticide‐treated seeds. Detailed results and a detailed description of the measuring protocol can be found in Zwertvaegher et al . For this study, only the results of the samples shown in Table were used.…”

“…Quantitative measurement of the abrasion potential of treated seeds is generally done using the Heubach dust meter, an example of a rotating drum dustiness tester. It was originally developed to determine the dustiness of pigments, but is now in more general use as a dustiness tester for powders of occupational health significance …”

“…Shortly after relating neonicotinoid‐laden dust particles to bee killing incidents, the Heubach test was introduced as the standard test to evaluate the abrasion potential of seed batches and has been included in many dust drift studies and registration procedures . The test, however, does not allow for an assessment of the particle size, does not take the entire driftable dust fraction into account (see below) and does not represent an actual seeding process.…”

An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 1: new molecules, metabolism, fate, and transport

“…Since then, attention has been paid to the reduction of particulate matter expulsion using modified drilling machines fitted with devices in order to reduce particulate emissions and proper handling of coated seeds (Biocca et al 2017;Manzone et al 2015;Manzone and Tamagnone 2016;Pochi et al 2015a, b). However, the abrasion potential of seeds still has an important ecological impact without clear benefits in terms of crop yields (Sgolastra et al 2017b;Zwertvaegher et al 2016). …”