188.8.131.52.2.2. Dust extraction
1) Dust from maize-dressed seeds is obtained by Heubach method. This method is commonly performed to measure the seed dustiness (Heimbach, 2008). In the Heubach method, treated seeds are mechanically stressed inside a rotating drum. A vacuum pump produces an air flow through the rotating drum, the connected glass cylinder and the attached filter. By the air flow, abraded dust particles are transported out of the rotating drum through the glass cylinder and subsequently through the filter unit. Fine dust particle (Ø<0.5 mm) are deposited onto a filter while coarse non-floating particles are separated and collected in the glass cylinder.
2) The dust retained by the Heubach cylinder filter and the other particles extracted with Ø<45 µm should be used in the toxicity test. Fine and coarse dust particles are mashed and sieved with a precision 45 µm mesh sieve in order to use only small particles for the test, which are more likely to drift.