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Biomedical subjects

Erik Tielemans

Publications and source records attributed to Erik Tielemans.

9 recordsLinked to original sources
PubMed2006

Occupational exposure during application and removal of antifouling paints.

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 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.

Air Pollutants, Occupational↗
PubMed2006

Quantitative self-assessment of exposure to solvents among shoe repair men.

Self-assessment of exposure (SAE) refers to any exposure assessment methodology wherein the worker takes an active role in establishing his or her exposure status. The objective of this study was to investigate the reliability and feasibility of SAE approaches among shoe repair workers collecting exposure data over a 3 month period. This study was conducted in 26 Dutch shoe repair shops, which were divided into two groups of SAE with different levels of expert supervision. Participants in group 1 received only written instructions on sampling methods, whereas workers in group 2 were also instructed face-to-face by an occupational hygienist. Participants were asked to do 20 (group 1) or 14 (group 2) measurements by themselves. In group 2, an additional 6 measurements in each company were conducted under supervision of an expert. Organic solvents were measured by passive samplers (3M badges) and a sum score for volatile organic compounds (VOC score) was used in data analysis. Mixed effect models and principal component analysis were used to compare concentration levels and exposure variability between group 1 and group 2. Finally, 473 out of the 520 distributed samplers (91%) were available for analysis. Measurements in group 1 were not evenly spread over the 3 month period, whereas dispersal of measurements was much better if experts were more closely involved (group 2). No significant differences in average VOC scores were found between group 1 and group 2. The exposure variability in group 1 appeared to be significantly larger than that in group 2. However, analysis within group 2 showed that no differences exist in geometric means and exposure variability between 'expert' and 'self-assessment' measurements. Thus, the study results are ambiguous with respect to the reliability of SAE, and more research is needed to corroborate and refine the present results. This new methodology can, if proven reliable, be seen as a cost-effective way of collecting exposure data.

Air Pollutants, Occupational↗
PubMed2005

Inhalation exposure to isocyanates of car body repair shop workers and industrial spray painters.

As part of a large-scale epidemiological study, occupational isocyanate exposure was assessed in spray-painting environments. The aim was to assess which compounds contribute to isocyanate exposure in car body repair shops and industrial painting companies, and to identify tasks with high risk of isocyanate exposure. Mainly personal task-based samples (n = 566) were collected from 24 car body repair shops and five industrial painting companies using impingers with DBA in toluene. Samples were analysed by LC-MS for isocyanate monomers, oligomers and products of thermal degradation. From the 23 analysed compounds, 20 were detected. Exploratory factor analysis resulted in a HDI, TDI and MDI factor with the thermal degradation products divided over the TDI and MDI factors. The HDI factor mainly consisted of HDI oligomers and was dominant in frequency and exposure levels in both industries. Spray painting of PU lacquers resulted in the highest exposures for the HDI factor (<LOD-2643 microg/m(3) NCO), with no significant difference between the industries. Exposure variability during PU spray painting was large with a variability over time of (ww)S(2) = 9.1 compared with between-worker variability of (bw)S(2) = 1.6. Lower level exposure to the HDI factor was found during other painting-related tasks and even tasks without direct exposure to paint. Exposure to the TDI factor was found more regularly in car body repair shops than in industrial painting companies. Exposure levels were low (<LOD-5 microg/m(3) NCO) compared with the HDI factor and no clear contrast in levels between the tasks was observed. Exposure to the MDI factor was found incidentally during spraying and welding in car body repair shops (<LOD-0.5 microg/m(3) NCO). The results indicate that paint is the most important source and major contributor of isocyanate exposure in both industries with highest exposures during PU spraying. However, since respiratory protection is less extensively used during other tasks, lower level exposure during these other tasks may significantly contribute to the internal dose.

Air Pollutants, Occupational↗
PubMed2005

Dermal exposure assessment to benzene and toluene using charcoal cloth pads.

Charcoal cloth pads have been used to assess volatile chemicals on the skin in a laboratory setting; however, they have not yet been applied to measure dermal exposure in occupational settings. This study aimed at evaluating whether charcoal pads can be used to assess dermal exposure to benzene and toluene in workers of a petrochemical plant. Inhalation and dermal exposure levels to benzene and toluene were assessed for workers of a petrochemical plant performing different jobs. Benzene uptake was assessed by determining S-phenylmercapturic acid in workers' urine samples. Dermal exposure levels on the charcoal pads were adjusted for ambient air levels of benzene and toluene by subtracting the amount of benzene or toluene measured in personal air from the amount of benzene or toluene measured on the charcoal pad. In general, measured external and internal exposure levels were low. The estimated contribution of the dermal route to internal benzene exposure levels was less than 0.06% for all jobs. Toluene personal air concentrations and benzene and toluene dermal exposure levels differed statistically significantly between job titles. For benzene, differences between jobs were larger for adjusted dermal exposures (maximum 17-fold, P = 0.02) than for inhalation exposures (maximum two-fold, P = 0.08). Also for toluene, although less clear, differences between jobs were larger for adjusted dermal exposures (maximum 23-fold, P = 0.01) as compared to inhalation exposures (maximum 10-fold, P = 0.01). Charcoal pads appeared to measure dermal exposures to benzene and toluene in addition to ambient air levels. Future studies applying charcoal cloth pads for the dermal exposure assessment at workplaces with higher dermal exposure to organic solvents may provide more insight into the biological relevance of dermal exposure levels measured by charcoal cloth pads. In addition, the design of the dermal sampler might be improved by configuring a dermal sampler, where part of the sampler is protected against direct contact and splashes, but still permeable for the gas phase. This design would most likely result in a better ability to correct for airborne concentrations at a given body location.

Administration, Cutaneous↗
PubMed2004

Dermal exposure during filling, loading and brushing with products containing 2-(2-butoxyethoxy)ethanol.

INTRODUCTION: Limited quantitative information is available on dermal exposure to chemicals during various industrial activities. Therefore, within the scope of the EU-funded RISKOFDERM project, potential dermal exposure was measured during three different tasks: filling, loading and brushing. DEGBE (2-(2-butoxyethoxy)ethanol) was used as a 'marker' substance to determine dermal exposure to the products that workers were handling. METHODS: Potential whole body exposure was measured using self-constructed cotton sampling pads on 11 body locations. Cotton gloves were used to determine the contamination of both hands. Bulk samples were collected to determine the concentration of DEGBE so as to be able to calculate exposure to the handled product. RESULTS: A total of 94 task-based measurements were performed, 30 on filling, 28 on loading and 36 on brushing, which resulted in potential dermal hand exposure to the handled product of 4.1-18 269 mg [geometric mean (GM) 555.4, n = 30], 0.3-27745 mg (GM 217.0, n = 28) and 11.3-733.3 mg (GM 98.4, n = 24) for each of the scenarios, respectively. Potential whole body exposure to the product during filling and loading ranged from 1.67 to 155.0 (GM 15.2, n = 9) and <LOD to 176.2 (GM 0.30, n = 10). Because of sampling and analytical problems, whole body exposure during brushing could not be determined. CONCLUSION: Dermal exposure during filling and loading were of the same order of magnitude, while brushing resulted in much lower exposure levels, probably due to differences in work activities and work precision. For each of the scenarios, contamination was mainly found on the hands, representing up to 96% of the total exposure for filling. For filling and loading the most important source of variability in exposure was due to between-company variability rather than to either between-worker or within-worker variability. The pooled between-worker variability was the most important source of variability in dermal exposure levels for the brushing scenario.

Analysis of Variance↗
PubMed2004

Effectiveness of personal protective equipment: relevance of dermal and inhalation exposure to chlorpyrifos among pest control operators.

This study assessed the effectiveness of a custom fit personal protective equipment (PPE) program aimed at reducing occupational exposure to pesticides. The intervention study was carried out on 15 pest control operators (PCOs) during mixing/loading and application of chlorpyrifos. Each worker was measured twice; first while the worker used PPE as normal (baseline measurement), and second after making some adjustments to the PPE (postintervention measurement). The applied intervention consisted of a tight-fitting, full-face respirator, fit-testing, long gloves, chemical-proof boots, a Tyvek hood, and an instruction video that was shown prior to putting on the PPE. A comprehensive evaluation program was used for the within-subject comparisons, including assessment of potential dermal exposure, actual dermal exposure, inhalation exposure, and internal dose as measured by the urinary metabolite 3,5,6-trichloro-2-pyridinol (TCP). The PPE program resulted in a significant increase in fit factors from a mean of 670 to 132,000. Actual dermal exposure levels decreased on average by fourfold after implementation of the PPE program (baseline AM = 132.1 microg; postintervention AM = 32.6 microg). The TCP levels in urine collected 24-32 hours after spray activities were lower in the postintervention data set (AM = 21.2 microg TCP/g creatinine vs. AM = 13.9 microg TCP/g creatinine). However, it is impossible to attribute these differences totally to the PPE program since workers had significant and varying urinary TCP levels before onset of spraying activities. Linear regression models showed that dermal exposure was only a predictive parameter for TCP levels in urine in the baseline data set. Although the results should be interpreted cautiously this study suggests a protective effect of the evaluated PPE program.

Administration, Cutaneous↗
PubMed2002

Sources of bias in studies among infertility clients.

An assumption in case-control studies is that forces of selection are the same for cases and controls. This may not be true for studies of male infertility among infertility clients. Earlier reproductive outcomes may introduce modification of risk behavior or differential referral. Selection bias might also occur when infertile males are compared with fertile males. Partners of sterile men are more likely to have "normal" fertility, while partners of a reference group of normozoospermic men tend to have a lower fertility potential. The latter may lead to overrepresentation of causes of reduced female fertility and introduce bias into estimates of risk factors shared by couples. The relation between cigarette smoking and semen quality was studied in a population of infertility clients from the Netherlands during 1995-1996. To reduce the potential for bias, this relation was studied first in a restricted population less aware of the type of infertility involved. The odds ratio of infertility with smoking was elevated in the restricted population as compared with the total population. Adjustment for smoking by the female partner increased the odds ratios for male smoking as well. These results indicate that bias may occur in clinic-based fertility studies because of different forms of selection.

Adult↗
PubMed2002

A proposal for evaluation of exposure data.

There is a growing need for transparency concerning ways in which existing exposure data are weighted for their relative value and quality. Currently, this evaluation is largely subjective and is dependent on the quality of the judgement of the individual assessor or expert group. In this paper some general guidelines are presented for a quality assessment procedure. Such a predetermined procedure potentially enhances the consistency among different assessors and assessments and facilitates harmonization of assessment procedures. The guidelines are presented in the context of a decision tree with four decision rules for data quality, i.e. 'availability of occupational hygiene information', 'variability and precision issues', 'internal validity' and 'external validity'. These methodological issues are considered to be the most important aspects of data quality and will be discussed in this paper. The decision tree eventually results in three quality classes, i.e. exposure data providing sufficient information, supplementary information and data which should be excluded from the exposure assessment process. The guidelines should not be used in a rigid manner but have to be interpreted in the light of the particular circumstances and purposes of the assessment.

Chemical Industry↗