There has been a growing awareness of the importance of dermal exposure in recent years. A wide range of techniques are employed to measure exposure, of which surrogate skin techniques such as patch sampling and whole body sampling are frequently used. One of the problems associated with dermal sampling is that different methods often produce different results due to differences in the principles involved in sample collection. As a consequence little progress towards establishing dermal exposure limits has been made. Both patches and clothing act as passive samplers and are intended to collect all of a substance deposited on them. This paper details the principles underlying patch and whole body sampling and outlines some of the advantages and disadvantages of each. A conceptual model has recently been proposed for dermal exposure and the role that surrogate techniques may play in the application of this model is discussed. Finally, suggestions are made as to how these techniques may be made more relevant and areas of future research highlighted.

The Department of Health has recently published a report from the CFS/ME Working Group which concluded that chronic fatigue syndrome (CFS) should be recognized as a chronic illness. Symptoms consistent with CFS are often reported by people who consider their health has been affected by exposure to pesticides, but the Working Group concluded that this type of exposure is not a common trigger for the syndrome. The Veterinary Medicines Directorate (VMD) collects self-assessed reports of ill health in humans associated with veterinary medicines under their Suspected Adverse Reaction Surveillance Scheme. The reporters have mainly been sheep farmers. These reports were used to investigate the possible relationship between chronic fatigue (CF) and exposure to organophosphate pesticides in sheep farming. The overall aim of the study was to investigate a possible association between exposure to organophosphates and the development of CF amongst people who consider their health has been affected by pesticides in sheep farming. The hypothesis investigated was that repeated exposure to organophosphate pesticides in sheep dip may increase the probability of developing CF. A group of mostly sheep farmers who had reported to the VMD surveillance scheme were identified. We planned to use a retrospective case-control study design but the initial symptoms reports were not sufficiently reliable to enable this. The study population was asked to complete two questionnaires. The first questionnaire was designed to identify the history of exposure of subjects to organophosphate pesticides, and their exposure was then reconstructed using a metric specifically developed for this purpose. The second questionnaire collected detailed information to identify whether the subjects had CF when they originally reported to the VMD and at the time of the survey. The questionnaire was sent to a total of 206 subjects, of whom 28 had moved home. A total of 37% of the remaining 178 subjects participated. There was a high prevalence of CF amongst those who completed the questionnaire and this has generally persisted since the subjects reported to the VMD. Higher CF scores were associated with higher exposure to organophosphate pesticides. CF is very common amongst those who consider their health was affected by pesticides and we have shown there is limited evidence of an association between exposure to organophosphates and CF. Further research is needed to investigate the cause of this syndrome amongst farmers exposed to pesticides.

There has been a growing awareness of the importance of dermal exposure in recent years. A wide range of techniques are employed to measure exposure, of which surrogate skin techniques such as patch sampling and whole body sampling are frequently used. One of the problems associated with dermal sampling is that different methods often produce different results due to differences in the principles involved in sample collection. As a consequence little progress towards establishing dermal exposure limits has been made. Both patches and clothing act as passive samplers and are intended to collect all of a substance deposited on them. This paper details the principles underlying patch and whole body sampling and outlines some of the advantages and disadvantages of each. A conceptual model has recently been proposed for dermal exposure and the role that surrogate techniques may play in the application of this model is discussed. Finally, suggestions are made as to how these techniques may be made more relevant and areas of future research highlighted.