S E Semple

Publications of S E Semple

• Development of a Task-Exposure Matrix (TEM) for Pesticide Use (TEMPEST).

  Authors: F D Dick, S E Semple, M van Tongeren, B G Miller, P Ritchie, D Sherriff, J W Cherrie

  The Annals of occupational hygiene. 03/2010; 54(4):443-52.

  Pesticides have been associated with increased risks for a range of conditions including Parkinson's disease, but identifying the agents responsible has proven challenging. Improved pesticidePesticides have been associated with increased risks for a range of conditions including Parkinson's disease, but identifying the agents responsible has proven challenging. Improved pesticide exposure estimates would increase the power of epidemiological studies to detect such an association if one exists. Categories of pesticide use were identified from the tasks reported in a previous community-based case-control study in Scotland. Typical pesticides used in each task in each decade were identified from published scientific and grey literature and from expert interviews, with the number of potential agents collapsed into 10 groups of pesticides. A pesticide usage database was then created, using the task list and the typical pesticide groups employed in those tasks across seven decades spanning the period 1945-2005. Information about the method of application and concentration of pesticides used in these tasks was then incorporated into the database. A list was generated of 81 tasks involving pesticide exposure in Scotland covering seven decades producing a total of 846 task per pesticide per decade combinations. A Task-Exposure Matrix for PESTicides (TEMPEST) was produced by two occupational hygienists who quantified the likely probability and intensity of inhalation and dermal exposures for each pesticide group for a given use during each decade. TEMPEST provides a basis for assessing exposures to specific pesticide groups in Scotland covering the period 1945-2005. The methods used to develop TEMPEST could be used in a retrospective assessment of occupational exposure to pesticides for Scottish epidemiological studies or adapted for use in other countries.

• A training exercise in subjectively estimating inhalation exposures.

  Authors: S E Semple, L A Proud, S N Tannahill, M E Tindall, J W Cherrie

  Scandinavian journal of work, environment & health. 01/2002; 27(6):395-401.

  OBJECTIVES: This study examined whether it is possible to train occupational hygienists to estimate inhalation exposures reliably from limited occupational information using a new method and assessedOBJECTIVES: This study examined whether it is possible to train occupational hygienists to estimate inhalation exposures reliably from limited occupational information using a new method and assessed improvements in the quality of the estimate using the aggregate from multiple assessors. METHODS: Five occupational hygienists estimated inhalation exposure for 40 tasks covering a range of chemical hazards using a recently developed subjective modeling technique supplemented by detailed guidance notes. The measured exposure levels were used to determine the validity of the method. The correlation coefficients of the log-transformed data were used to assess the discriminative power of the method, and the ratio of the mean estimate to measured values was used to measure accuracy. RESULTS: There was good-to-excellent agreement between the assessors' estimates and the measured data, the correlation coefficients ranging from 0.73 to 0.85. There was a tendency for assessors to overestimate the exposure levels by, on the average, two- to fourfold. Aggregating the assessors' estimates helped to improve the correlation coefficient to 0.88, the overestimation being 2.6-fold. Using more than three assessors for aggregate estimates did not improve the reliability of the method. CONCLUSIONS: Overall, the assessors found the method to be useful in generating exposure estimates that correlate well with measured levels. The provision of high-quality guidance information is likely to be important in the generation of reliable exposure estimates. The method is likely to be of use in epidemiologic studies in which limited exposure data are available.