Experimental assessment of operator exposure by inspiration, for highly-charged droplets produced by an Electrodyn crop sprayer

An investigation has been carried out of the amount of pesticide material inspired by the operator of a hand-held Electrodyn ® crop spraying device [COFFEE Outlook on Agriculture10 , 350–356 (1981)]. The ‘operator’ in this case was a full-size tailor’s mannequin fitted with a nasal filtration unit which was connected to a ‘breathing machine’. The quantity of material inspired during a given spraying period was determined by quantitative fluorimetric analysis of a Uvitex-OB tracer dye contained in the formulation collected by the nasal sampler. Both still and moving air situations have been investigated, the latter in a large wind tunnel. In still air the inspired material amounted to about 10 −4 % of the total volume sprayed. In moving air (wind speed 3 m s −1 ), the quantity of material inspired during downwind spraying (the recommended orientation) was too low to be assessed by the methods used, but was established as being less than 2.5×10 −6 % of the total volume sprayed in any period.

The correlation between the results obtained for a number of different types of personal sampling device and the inspired volume was also assessed. The results in terms of the mean and [standerd deviations] of the sampling ratio (amount collected on sampler/amount inspired) for the three sampler types tested in still air were 0.74 [0.25] 0.60 [0.26] and 0.30 [0.17] respectively. Of the samplers tested, the best results were obtained for the ‘7-hole’ device [HEALTH AND SAFETY EXECUTIVE, MDHS 14 (1986)]. In the case of downwind spraying, the volumes collected were again too low for analysis.

A recommendation is made that these measurements be repeated under appropriate field conditions.