Dermal exposure to dry powder spray paints using PXRF and the method of Dirichlet tesselations

This paper describes workplace dermal exposure measurements that were carried out by the Health and Safety Laboratory as part of the EU RISKOFDERM project to measure dust contamination. Exposure to dry powder spray paints was measured at five sites on 12 subjects. Twenty-two samples were obtained, of which eight contained triglycidyl isocyanurate (TGIC) and 14 did not. All subjects wore Tyvek whole body oversuits and some wore sampling gloves. These were either analysed in their entirety to extract the TGIC or surface scanned over representative areas using a portable X-ray fluorescence spectrometer (PXRF) to detect barium or titanium in the fillers of the paints. The method of Dirichlet tessellation was used to map the scans and the technique was developed further for these studies to extend measurements to gloves and to take limits of detection into consideration. The PXRF allowed dusts to be measured in situ that would otherwise be difficult to extract from the material and analyse by other means. The geometric mean surface loading rate of the 22 oversuits was 43 micro g/cm/(2)/h (GSD = 6.0) and of the 23 pairs of sampling gloves was 970 micro g/cm(2)/h (GSD = 8.6). Exposure patterns could be attributed to the arrangements of the subjects, spray booths and the workpieces. Similar exposures were found for TGIC and titanium fillers in factories with similar methods of ventilation.