Yvette Christopher

Publications of Yvette Christopher

• An assessment of dermal exposure to heavy fuel oil (HFO) in occupational settings.

  Authors: Yvette Christopher, Martie Van Tongeren, Jan Urbanus, John W Cherrie

  The Annals of occupational hygiene. 04/2011; 55(3):319-28.

  Heavy fuel oil (HFO) components are a group of heavy petroleum streams produced in oil refineries from crude oil. Due to its physicochemical properties, the dermal route is an important route ofHeavy fuel oil (HFO) components are a group of heavy petroleum streams produced in oil refineries from crude oil. Due to its physicochemical properties, the dermal route is an important route of exposure. However, no information on dermal exposure levels for HFO has previously been published. A method for measuring dermal HFO levels was developed using wipe sampling and measuring phenanthrene and naphthalene as markers of HFO exposure. Measurement surveys were carried out in four different types of facilities: oil refineries, distribution terminals, energy providers, and an engine building and repair company. Dermal wipe samples were collected from different anatomical regions: neck, hands, and forearms. The frequency of tasks with potential for dermal HFO exposure was generally low at these facilities, with the exception of the distribution terminals and the engine building and repair site. The geometric mean (GM) dermal load on the hands was ∼0.1 μg cm(-2) for both left and right hand and 0.013 and 0.019 μg cm(-2) for the left and right forearm, respectively. With one exception, all results from the neck samples were below the limit of detection. The highest dermal loads for the hands and forearms were found in the engine building and repair facility (hands: GM = 1.6 μg cm(-2); forearms: GM = 0.41 μg cm(-2)). The tasks with the highest dermal loads were the maintenance (hands: GM = 1.7 μg cm(-2)) and cleaning tasks (hands: GM = 0.24 μg cm(-2)). Actual dermal loads were low when compared with workplace dermal exposure measurements reported by other researchers for similar scenarios with other substances. This may be explained by high compliance of gloves use by workers during HFO handling tasks and likely avoidance of contact with HFO due to its high viscosity and the requirement to keep HFO at elevated temperatures during storage, transport, and use.

• Occupational Dermal Exposure to Heavy Fuel Oils

  Authors: Yvette Christopher, M van Tongeren, Hilary Cowie, John W Cherrie

  01/2008;

  Occupational Dermal Exposure to Heavy Fuel Oils TM/07/05

• Occupational exposure during application and removal of antifouling paints.

  Authors: Ingrid Links, Katinka E Van Der Jagt, Yvette Christopher, Marc Lurvink, Jody Schinkel, Erik Tielemans, Joop J van Hemmen

  The Annals of occupational hygiene. 04/2007; 51(2):207-18.

  Exposure data on biocides are relatively rare in published literature, especially for secondary exposure. This is also the case for antifouling exposure. Therefore, a field study was carried outExposure data on biocides are relatively rare in published literature, especially for secondary exposure. This is also the case for antifouling exposure. Therefore, a field study was carried out measuring exposure to antifouling paints. Both primary exposure (rolling and spraying) and secondary exposure (during sand blasting) were studied. Exposure during rolling was measured in boatyards where paints containing dichlofluanid (DCF) were applied. Spraying was measured in dockyards (larger than boatyards) where paints containing copper were applied. Furthermore, during sand blasting the removal of old paint layers containing copper was measured. A total of 54 datasets was collected, both for inhalation and dermal exposure data. For paint and stripped paint bulk analyses were performed. The following values are all arithmetic means of the datasets. Inhalation of copper amounted to 3 mg m-3 during spraying and to 0.8 mg m-3 during sand blasting. Potential body exposure loading amounted to 272 mg h-1 copper during spraying and 33 mg h-1 during sand blasting. For dichlofluanid the inhalation exposure loading was 0.14 mg m-3 during rolling, whereas the potential body exposure loading was 267 mg h-1 and potential hand exposure loading 277 mg h-1. The results for primary exposure compare well to the very few public data available. For the secondary exposure (sand blasting) no comparable data were available. The present study shows that the exposure loading should be considered more extensively, including applicable protective gear. In this light the findings for the potmen during sand blasting suggest that personal protective equipment should be (re)considered carefully.

• Covert observation in practice: lessons from the evaluation of the prohibition of smoking in public places in Scotland.

  Authors: Mark Petticrew, Sean Semple, Shona Hilton, Kaen S Creely, Douglas Eadie, Deborah Ritchie, Catherine Ferrell, Yvette Christopher, Fintan Hurley

  BMC public health. 02/2007; 7(147):204.

  BACKGROUND: A ban on smoking in wholly or substantially enclosed public places has been in place in Scotland since 26th March 2006. The impact of this legislation is currently being evaluated inBACKGROUND: A ban on smoking in wholly or substantially enclosed public places has been in place in Scotland since 26th March 2006. The impact of this legislation is currently being evaluated in seven studies, three of which involve direct observation of smoking in bars and other enclosed public places. While the ethical issues around covert observation have been widely discussed there is little practical guidance on the conduct of such research. A workshop was therefore convened to identify practical lessons learned so far from the Scottish evaluation. METHODS: We convened a workshop involving researchers from the three studies which used direct observation. In addition, one of the fieldwork managers collected written feedback on the fieldwork, identifying problems that arose in the field and some solutions. RESULTS: There were four main themes identified: (i) the difficulty of achieving and maintaining concealment; (ii) the experience of being an observer; (iii) the risk of bias in the observations and (iv) issues around training and recruitment. These are discussed. CONCLUSION: Collecting covert observational data poses unique practical challenges, in particular in relation to the health and safety of the researcher. The findings and solutions presented in this paper will be of value to researchers designing similar studies.

• Covert observation in practice: lessons from the evaluation of the prohibition of smoking in public places in Scotland

  Authors: Mark Petticrew, Sean Semple, Shona Hilton, Kaen Creely, Douglas Eadie, Deborah Ritchie, Catherine Ferrell, Yvette Christopher, Fintan Hurley

  BMC Public Health. 01/2007;

  Abstract Background A ban on smoking in wholly or substantially enclosed public places has been in place in Scotland since 26^thMarch 2006. The impact of this legislation is currentlyAbstract Background A ban on smoking in wholly or substantially enclosed public places has been in place in Scotland since 26^thMarch 2006. The impact of this legislation is currently being evaluated in seven studies, three of which involve direct observation of smoking in bars and other enclosed public places. While the ethical issues around covert observation have been widely discussed there is little practical guidance on the conduct of such research. A workshop was therefore convened to identify practical lessons learned so far from the Scottish evaluation. Methods We convened a workshop involving researchers from the three studies which used direct observation. In addition, one of the fieldwork managers collected written feedback on the fieldwork, identifying problems that arose in the field and some solutions. Results There were four main themes identified: (i) the difficulty of achieving and maintaining concealment; (ii) the experience of being an observer; (iii) the risk of bias in the observations and (iv) issues around training and recruitment. These are discussed. Conclusion Collecting covert observational data poses unique practical challenges, in particular in relation to the health and safety of the researcher. The findings and solutions presented in this paper will be of value to researchers designing similar studies.

• How important is inadvertent ingestion of hazardous substances at work?

  Authors: John W Cherrie, Sean Semple, Yvette Christopher, Ahsan Saleem, Graeme W Hughson, Andrew Philips

  The Annals of occupational hygiene. 11/2006; 50(7):693-704.

  Much is known about human exposure to workplace hazardous substances by inhalation and from skin contact, but there has been little systematic research into ingestion of hazardous substances used atMuch is known about human exposure to workplace hazardous substances by inhalation and from skin contact, but there has been little systematic research into ingestion of hazardous substances used at work. This review attempts to identify whether inadvertent ingestion of hazardous substances is an important route of exposure in the workplace and examines possible methods that could be used to quantify ingestion exposure. A number of papers highlight jobs and substances where inadvertent ingestion may be important, typically through case reports or from a theoretical analysis. These scenarios involve exposure to some metals or metal compounds, pharmaceuticals, pesticides, some infectious agents, unsealed radioactive sources and some high molecular weight allergens. In total we estimate that about 4.5 million workers in the UK could have some regular non-trivial intake of hazardous substances by inadvertent ingestion. A conceptual analysis of inadvertent ingestion exposure highlights the role of hand-to-mouth and object-to-mouth events as the primary exposure processes. Two exposure 'compartments' are defined: the peri-oral area (i.e. the area of skin around the outside of the mouth) and the oral cavity. Several options are highlighted for exposure-related measurements, including peri-oral wipes, saliva samples, mouth-rinse samples, hand-wipes and under-nail scrapings. Further research is necessary to define which measurements may be most informative. Human behaviour has a key role in determining inadvertent ingestion exposure. For example, some people are habitual nail biters or repeatedly touch their mouth, both of which will increase the chance of ingesting contaminants on their hands. The frequency that people touch their face is dependant on the circumstances of their work and probably the degree of psychological stress they are under. A proper understanding of the importance of these factors will help in designing interventions to reduce the risks from ingesting hazardous substances at work. When making inhalation or dermal exposure measurements we recommend that details of personal behaviours should be recorded so that some estimate of ingestion risks can be inferred. It is possible that inadvertent ingestion of hazardous substances at work may become more important as employers put more emphasis on controlling inhalation and dermal exposures. Further research is necessary to ensure that risk reduction strategies for inadvertent ingestion of hazardous substances are appropriate and effective.

• Size selective dustiness and exposure; simulated workplace comparisons.

  Authors: Derk H Brouwer, Ingrid H M Links, Sjaak A F De Vreede, Yvette Christopher

  The Annals of occupational hygiene. 08/2006; 50(5):445-52.

  A simulated workplace study was conducted to investigate the relation between inhalation exposure and dustiness determined with a rotating drum dustiness tester. Three powders were used in the study,A simulated workplace study was conducted to investigate the relation between inhalation exposure and dustiness determined with a rotating drum dustiness tester. Three powders were used in the study, i.e. magnesium stearate, representing a very dusty powder, and aluminium oxide and calcium carbonate, representing low and very low dusty powders, respectively. Two scenarios of handling small volume of powders were included; sweeping/cleaning and scooping/weighing/adding. Size-selective dust exposure was assessed using MultiDust (dual-fraction) IOM and RespiCon sampling heads. For the present operation scenarios, dustiness showed itself to be the major determinant of exposure and explained approximately 70% of the exposure variances. The ratios of respirable and inhalable fractions as determined by dustiness tests were comparable with the ratios observed for exposure. The results emphasize the relevance of dustiness as a parameter to characterize substances according to potential for exposure.

• Task-based dermal exposure models for regulatory risk assessment.

  Authors: Nicholas D Warren, Hans Marquart, Yvette Christopher, Juha Laitinen, Joop J van Hemmen

  The Annals of occupational hygiene. 08/2006; 50(5):491-503.

  The regulatory risk assessment of chemicals requires the estimation of occupational dermal exposure. Until recently, the models used were either based on limited data or were specific to a particularThe regulatory risk assessment of chemicals requires the estimation of occupational dermal exposure. Until recently, the models used were either based on limited data or were specific to a particular class of chemical or application. The EU project RISKOFDERM has gathered a considerable number of new measurements of dermal exposure together with detailed contextual information. This article describes the development of a set of generic task-based models capable of predicting potential dermal exposure to both solids and liquids in a wide range of situations. To facilitate modelling of the wide variety of dermal exposure situations six separate models were made for groupings of exposure scenarios called Dermal Exposure Operation units (DEO units). These task-based groupings cluster exposure scenarios with regard to the expected routes of dermal exposure and the expected influence of exposure determinants. Within these groupings linear mixed effect models were used to estimate the influence of various exposure determinants and to estimate components of variance. The models predict median potential dermal exposure rates for the hands and the rest of the body from the values of relevant exposure determinants. These rates are expressed as mg or microl product per minute. Using these median potential dermal exposure rates and an accompanying geometric standard deviation allows a range of exposure percentiles to be calculated.

• How important is inadvertent ingestion of hazardous substances at work?

  Authors: John W Cherrie, Sean E Semple, Yvette Christopher, Ahsan Saleem, Graeme W Hughson, Andrew Phillips

  01/2006; 50:693-704.

  Much is known about human exposure to workplace hazardous substances by inhalation and from skin contact, but there has been little systematic research into ingestion of hazardous substances used atMuch is known about human exposure to workplace hazardous substances by inhalation and from skin contact, but there has been little systematic research into ingestion of hazardous substances used at work. This review attempts to identify whether inadvertent ingestion of hazardous substances is an important route of exposure in the workplace and examines possible methods that could be used to quantify ingestion exposure. A number of papers highlight jobs and substances where inadvertent ingestion may be important, typically through case reports or from a theoretical analysis. These scenarios involve exposure to some metals or metal compounds, pharmaceuticals, pesticides, some infectious agents, unsealed radioactive sources and some high molecular weight allergens. In total we estimate that about 4.5 million workers in the UK could have some regular non-trivial intake of hazardous substances by inadvertent ingestion. A conceptual analysis of inadvertent ingestion exposure highlights the role of hand-to-mouth and object-to-mouth events as the primary exposure processes. Two exposure 'compartments' are defined: the peri-oral area (i.e. the area of skin around the outside of the mouth) and the oral cavity. Several options are highlighted for exposure-related measurements, including peri-oral wipes, saliva samples, mouth-rinse samples, hand-wipes and under-nail scrapings. Further research is necessary to define which measurements may be most informative. Human behaviour has a key role in determining inadvertent ingestion exposure. For example, some people are habitual nail biters or repeatedly touch their mouth, both of which will increase the chance of ingesting contaminants on their hands. The frequency that people touch their face is dependant on the circumstances of their work and probably the degree of psychological stress they are under. A proper understanding of the importance of these factors will help in designing interventions to reduce the risks from ingesting hazardous substances at work. When making inhalation or dermal exposure measurements we recommend that details of personal behaviours should be recorded so that some estimate of ingestion risks can be inferred. It is possible that inadvertent ingestion of hazardous substances at work may become more important as employers put more emphasis on controlling inhalation and dermal exposures. Further research is necessary to ensure that risk reduction strategies for inadvertent ingestion of hazardous substances are appropriate and effective.

• Excluding exposure data of very poor quality is a core principle for regulatory risk assessment.

  Authors: Erik Tielemans, Yvette Christopher, Hans Marquart, Monique Groenewold, Joop Van Hemmen

  The Annals of occupational hygiene. 09/2002; 46(6):559-60; author reply 560.