Pilot study to investigate exposure to endotoxin in farmworkers performing sheep dipping

Preliminary observations have identified endotoxin to be present in the bath used for dipping sheep. A pilot study was performed at six farms to measure airborne concentrations of endotoxin to which workers dipping sheep are currently exposed and to quantify the range of concentrations of endotoxin in dipping baths both before and after sheep dipping.Total inhalable personal samples were collected from workers performing sheep dipping. Static samples were also obtained from two sites at each farm. Twenty-five ml samples of dip bath were collected before and after sheep dipping. In addition samples of the tapwater used to fill the dipping bath at each farm were obtained.Pre-dipping the endotoxin concentrations in the baths ranged from 16 E units/ml to 1248 E units/ml. Post-dipping the endotoxin concentrations in the bath samples ranged from 2880 E units/ml (240 ng/ml) to 27600 E units/ml (2300 ng/ml).The endotoxin concentrations in air from personal samples varied from 8 E units/m3 of air to 309 E units/m3. The range for paddlers was 8 to 67 E units/m3; for chuckers the range was 18 to 309 E units/m3 and for helpers the range was 14 to 150 E units/m3. Samples collected near the draining pens ranged from 7 E units/m3 to 242 E units/m3.The personal 8 hr time weighted average airborne endotoxin concentration ranged from 3 E units/m3 (paddler farm 4) to 85 E units/m3 (chucker/helper farm 2). The highest exposure for a paddler was 55 E units/m3 (farm 5). The highest endotoxin concentration for a helper was 36 E units/m3 (farm 1).The pilot study has identified the presence of airborne endotoxin during dipping. The endotoxin concentrations from air samples was low. This may reflect the limitations of the methodology used in collecting ‘total inhalable’ samples which may not be able to determine the exposure from splashing and large droplets. The bath samples have confirmed the presence of endotoxin in baths post-dipping.Further investigation is recommended into developing a suitable sampling method to quantify more clearly endotoxin exposure during sheep dipping including splashing on to mucous