Determination of dermal exposures during mixing, spraying and wiping activities.

Abstract

Dermal exposure measurements were collected as part of RISKOFDERM, a European dermal exposure study which aims to improve the understanding of the nature and range of dermal exposures to hazardous substances throughout the European Union. Exposure measurements were collected to enable a predictive model to be developed for regulatory risk assessment purposes. In this paper dermal exposure data are presented for three generic job tasks: spray painting, wiping surfaces and mixing/dilution of formulations. The particular workplace settings included a dockyard and three medical laboratories. In the dockyard the tasks involved spray application and mixing of anti-foulant paint. For laboratory workers the observed tasks were preparation of biocide solution and wiping of surfaces with the disinfectant. Each dermal exposure measurement was derived from the mass of trace analyte on cotton gloves and 11 fabric patches, which were cut from whole-body dosimeters, representing the main anatomical areas of the body. The percentage mass of trace analyte in the formulation was determined by analysis to enable the total mass of the product on the anatomical areas to be calculated. The sampling periods were recorded to enable calculation of the dermal exposure rate, which is expressed as micro g total formulation/cm(2)/h. The geometric mean dermal exposure rate for the hands during spray painting was 2760 micro g/cm(2)/h (n = 24). The exposure rate for the rest of the body was 175 micro g/cm(2)/h (n = 35). Mixing of the paint involved higher exposure rates for both the hands and body, with a geometric mean of 31 200 micro g/cm(2)/h (n = 9) for the hands and 327 micro g/cm(2)/h (n = 14) for the rest of the body. For small-scale routine disinfection of surfaces using small quantities of biocide the principal anatomical area affected was the hands, with a geometric mean dermal exposure rate of 1840 micro g/cm(2)/h (n = 6). During systematic disinfection of laboratory surfaces with larger quantities of the biocide solution, the geometric mean dermal exposure rate for the hands was increased to 139 000 micro g/cm(2)/h (n = 24). In this case there was increased exposure of the body: principally the arms, legs, chest and head. The measured dermal exposure rate during preparation of the biocides (mixing) was very low, with a geometric mean value for the hands of 13 micro g/cm(2)/h (n = 16). There was a high level of variability observed in the results within each task. It is suggested that dermal exposures are partly dependent on human behaviour and on the occurrence of accidental contact with contaminated surfaces. This makes interpretation of the results difficult for predictive risk assessment purposes.