The dermal exposure of bystanders was determined by measurements taken during application of the DimilinTM 80 WG suspension. Sampling was performed for both DimilinTM 80 WG application with vehicle-mounted unit and application with a hand-held sprayer. For organisational reasons, sampling to investigate the exposure of bystanders only took place with companies A and B.
As sampler for the exposure of bystanders a cut square section of TyvekTM fabric (1.75 m²; 1.90 x 0.92 m) representing the body surface of an adult was used. A rack frame to fix the TyvekTM sheets was constructed using 2.3 cm rectangular aluminium hollow section. The rack frame could easily be taken apart for transport, due to plastic joints. Both the aluminium sections and the plastic joints could easily be cleaned on site, thus avoiding cross-contaminations. To secure the rack frames particularly where powerful sprayers were used for application, they were hold down with sand sacks and additionally fixed with guy ropes. The frame constructions were chosen with respect to their practicability for the field trial but can be considered only as a surrogate for “real” bystander exposure.
Fig. 3.25 gives a blue print of the rack frame, Fig. 3.26 shows the measurement set up during the 2015 field study. The TyvekTM sheets attached to the rack frames, insofar as possible due to on-site conditions, were located downwind, at distances of 5 m and 10 m from the treated tree or group of trees. The minimum sampling time was 15 min so that possible spray drift after application was also recorded.
During the field studies measurements were carried out at 30 application sites, positioned at distances of 5 m and 10 m, which means that a total of 60 TyvekTM sheets were collected (Tab. 3.3). After sampling, the TyvekTM sheets were cut at a height of 1.00 m in order to assess the determined exposure of small children and adults separately. The potential exposure of a small child was calculated from the amount of diflubenzuron deposited on the lower segment of the TyvekTM sheet, the potential exposure of an adult from the amount of diflubenzuron deposited on both TyvekTM segments. In Fig. 3.27, the TyvekTM sheet cut at a height of 1 m can easily be seen.
Fig. 3.25 Blue print of the rack frame used for the measurement of bystander exposure.
Fig. 3.26 Set-up to measure the dermal and inhalation exposure of bystanders during the 2015 field study.
Fig. 3.27 Removal of a cut TyvekTM sheet from the rack frame during the 2014 field study.
Tab. 3.3 Overview of the TyvekTM sheets collected during the field studies to determine the bystanders’ dermal exposure.
Sprayer Task
Number of TyvekTM sheets
(5 m)
Number of TyvekTM sheets
(10 m)
Vehicle-mounted sprayer-
Application of the DimilinTM 80 WG suspension 15 15 Hand-held
sprayer Application of the DimilinTM 80 WG suspension 15 15
The TyvekTM sheets were cut up after sampling (Fig. 3.27), folded up with the contaminated side inside, wrapped airtight and lightproof in aluminium foil and stored in a sealable PE bag inside a portable cooler box at 4 °C. Thus cooled, the samples were transported to the laboratory and stored in a freezer at -20 °C prior to work up.
For processing, the folded TyvekTM sheets were cut up into approximately eight strips which were then put into one litre screwcap bottles using tweezers. The four segments of one measurement were processed simultaneously.
Fig. 3.28, Fig. 3.29 and Fig. 3.30 show the measurements carried out to determine bystanders` exposure during DimilinTM 80 WG application. The abbreviated designations of the individual measurements used in the captions are explained in Section 3.2 and the corresponding tasks are described in detail in Annex 2.
Fig. 3.28 Determination of bystanders` exposure during biocide application with vehicle-mounted sprayer. The picture shows the sampling VMS-application-dB-10 and VMS-application-iB-10 (company A).
Fig. 3.29 Determination of bystanders` exposure during biocide application with hand-held sprayer. The picture shows the sampling HHS-application-dB-8 and HHS-application-iB-8 (company A).
Fig. 3.30 Determination of bystander exposure during biocide application using a hand-held sprayer. The picture shows the sampling HHS-application-dB-11 and HHS-application-iB-11 (company A).
3.3.2.2 Inhalation exposure
The inhalation exposure of bystanders was recorded by stationary measurements only. The sampling devices were positioned downwind – where the terrain allows - at average adult breathing zone height (approximately 1.50 m). Sampling was carried out directly to the right or left of measurement set up for dermal exposure (see sampling tripod in Fig. 3.26).
Due to the quantification limit (see Section 3.3.1.2) the measurement had to last for at least 15 min. As a result of this minimum sampling time it was also possible to record any drift after spraying.
The following sampling points were selected at each application site:
• SP 4 stationary (s) at a distance of 5 m from the tree/tree row
• SP 5 stationary (s) at a distance of 10 m from the tree/tree row
The number and type of measurements of inhalation exposure is identical with the number of measurements of dermal exposure. The inhalation and dermal exposure of bystanders was always determined simultaneously (Tab. 3.3).
The particles were deposited in the form of an inhalable dust fraction on glass-fibre filters (ø 37 mm; organic binder). Air sampler pumps of the type SG 10/2 with 10 L/min were used. After sampling, the charged sampling tubes were wrapped in aluminium foil to protect them from light.
On all measurement days, the weather conditions at the measurement sites were also recorded. Temperature, air humidity and, where necessary, air velocity were determined with a multifunction anemometer (Testotherm). Atmospheric pressure was measured using a DVR 2 (Vaccubrand) unit. The recorded weather data will not be individually mentioned in this report.