Rehabilitation & workability

Interdisciplinary workplaces intervention strategies in MSD

Work-related musculoskeletal disorders are a persistent and expensive health challenge in all industrial countries including Switzerland. The cost of work-related MSD in Switzerland has been estimated to about 2-4 billion CHF per year. A relatively small group of patients causes relatively high health services costs and long absenteeism from work and furthermore show a high risk to loose workability.

This research aims to address the work-related MSD management issue through a cross-disciplinary intervention involving both clinical and occupational health competencies (rheumatology, occupational medicine, rheumatology, work psychology, ergonomics).

A cohort study of workers enduring MSD are selected from volunteering companies and randomised into two groups. Workers from the control group will benefit from an usual MSD management strategy involving a classic clinical therapy and the providing of basic information (i.e. info about ergonomics). Workers from the intervention group will benefit from a case-management including work-hardening treatment and workplace intervention.

The comparison of health and work-related variables prior and after intervention in the two groups will be used to assess the intervention efficiency and its economic benefits.

Work ability index (WAI) and ageing workers

The principal aim of our study is to develop a clinical method of follow-up of the ageing workers, in different services of the Administration (Canton de Vaud, Western Switzerland). Based on a standardized interview (risk assessment, subjective point of view of the volunteers about protective factors and solutions for prevention), questionnaires (WAI, Karasek) and workplace analysis, the method will be evaluated in terms of satisfaction of the volunteers, applicability (clinicians’ appreciation), and positive changing in the services (workers’ health, health prevention policies, organisational policies, retreat policies).

The WAI – Work Ability Index- is a clinical tool which was created by the Finnish Institute of Occupational Health, in order to help the occupational specialists in following the ageing workers. It is a sort of thermometer of the occupational health. It promises to be of good help for clinicians, but is relatively new in Switzerland (2005). One of the aims of our study is to assess this tool: applicability, acceptance, and reliability. Measuring the WAI anonymously and before any intervention may be a first step in assessing health risks, and may help with prioritising interventions.

Analysis of the factors influencing vocational rehabilitation in patients after renal or liver transplants performed between 1993-2003 at CHUV

Work is one of the most important measures of human existence, described in Abrams’ definition of Quality of Life (Qol) as one of the basic determinants of life satisfaction experienced by human beings. It is an essential factor for preserving psychological well-being, and a source of self-consciousness and self-realization. With organ transplantation patients obtain a new lease on life, both socially and professionally. Apart from the strictly medical aspects, organ transplantation changes the poor prognosis of the disease radically; the possibility of returning to work after transplantation not only enhances QoL, it is also an important rehabilitation factor and indicator of overall transplants success. It is therefore extremely important for healthcare professionals to appreciate the complex nature of the transplantation process, and to consider recipients in a wholistic fashion, encompassing the physical, social, psychological and vocational aspects.

This study explores vocational rehabilitation after renal and liver transplantation and will demonstrate the factors that influence return to work: for example renal or liver disease duration, time between stopping work and the transplantation; time between transplantation and return to work; economic and social difficulties; entitlement to disability insurance, etc.

The group being studied, renal or liver patients who received transplants at CHUV between 1993-2003 will respond to an extensive questionnaire about the medical, social, economic and vocational aspects of their cases.

European Working Conditions Survey (EWCS) – Swiss Data Analysis

In 2005 Switzerland was, for the first time, included in the European Working Conditions Survey (EWCS). The EWCS periodic is an important tool to evaluate the national Occupational Health situation in comparison with the other European countries. At the moment Switzerland has no “indicators of performance” related to occupational health so that the priority areas where research or interventions are needed are not known. EWCS should help us to detect where are the most important problems and which type of factors are the most relevant in this context.

This project aims to analyse the EWCS data at two levels: (1) national data will be analysed to assess the current Swiss situation (2) European data will be analysed to address research issues in regards of correlations between causal factors and subjective/objective occupational health outcomes.

Effects of particles on health

MARINA – Managing Risks of NanoMaterials

Collaboration with 47 Institutes worldwide within an FP7 project

The European Project MARINA (MAnaging RIisks of NAnomaterials) aims to develop specific reference methods for all the main steps in managing the potential risk of nanomaterials. MARINA addresses the four central themes in the risk management paradigm for nanomaterials: Materials, Exposure, Hazard and Risk.

IST’s contribution to the project is mainly on exposure-related issues through the study of airborne nanomaterial agglomerates, dispersion models and the development of worker protection strategies. In addition, IST leads the training activities and liaises with other European projects for this purpose.

Staff involved: Michael Riediker, Nastassja Lewinski, David Vernez, TBD PhD-student

NanoTOES - Nanotechnology: Training of Experts in Safety

Collaboration with 12 European Institutes within an FP7 project

The ITN NanoTOES (Nanotechnology: Training Of Experts in Safety) is establishing a network of research projects working towards the refinement and standardisation of existing methods and the development of novel assays. During this process it provides interdisciplinary training to early stage and experienced researchers working at the intersection of biosciences and nanosciences.

A suite of methods will be developed and validated in the NanoTOES project. Equally, the influence of biological entities (molecules, cells, tissues) on the properties of nanomaterials will be investigated. The topic of IST’s subproject is the influence of low-volatile organic pollutants on the intrinsic ROS production capacity.

Staff involved: Michael Riediker, Jiayuan Zhao

QNano – A pan-European infrastructure for quality in nanomaterials safety testing

Collaboration with 27 European Institutes within an FP7 project

QNano is a project providing access to “pan-European infrastructure for quality in nanomaterials safety testing”. QNano’s overall vision is the creation of a ‘neutral’ scientific & technical space in which all stakeholder groups can engage, develop, and share scientific best practice in the field. QNano has three pillars of activity: Transnational Access (TA), Joint Research Activities (JRA) and Networking Activities (NA). In TA, researchers can apply for free access to top level infrastructure across Europe thus enabling their research projects to go beyond the usual funding and technical obstacles. In JRA, leading teams develop novel methods to advance their fields that will afterwards be shared widely. Finally in NA, experts meetings are organized and the vast knowledge generated in the various European projects will be collected, polished and made available to the European researchers through a web-based knowledge hub and a series of training activities for early stage and experienced researchers. IST is leading the NA activity.

Staff involved: Michael Riediker, Mila Bender, Darren Hart

NanoImpactNet: The European Network on the Health and Environmental Impact of Nanomaterials

Collaboration with 24 European institutes and a network of 1000+ members within an FP7 project

NanoImpactNet is the European network on the health and environmental impact of nanomaterials. Sponsored by the European Commission (EC) and coordinated by IST, the 24 participating institutes are leading European research groups active in nanosafety, nanorisk assessment and nanotoxicology. NanoImpactNet brings together researchers, industry, the EC, government agencies and civil society to discuss future strategies, needs and concerns, to exchange ideas, and to further the safe and responsible development of nanotechnologies.

Consensus scientific positions help support the definition of regulatory measures and legislative implementation in Europe; strong two-way communication ensures efficient dissemination of information.

Staff involved: Michael Riediker, Darren Hart, Mila Bender (past: Nathalie Boschung, communication assistant)

National projects

Evaluation in vitro de la réactivité des particules fines et ultrafines

One of the most important mechanisms explaining the effects of nanoparticles (both ambient and engineered) seems to be their ability to generate oxidative stress at the cellular level. This oxidative stress can be caused directly by the particles (intrinsic stress) and it can be a response by immune and other cells (cell-derived stress). Thus, the measurement of NPs intrinsic oxidative potential could represent a first step in their hazard evaluation.

The aim of this methodological project was to characterize the oxidative potential for a panel of model nanoparticles (ambient and engineered) with three acellular assays (DTT test, DCFH test, ascorbic acid oxymetry test) and to use the results obtained to propose a reference method. In addition, we apply this selected assay to two real situations (exposure of workers to combustion-based particles and hazard evaluation of different engineered nanoparticles) in order to determine the parameters which influence the intrinsic reactivity.

Staff involved: Jean-Jacques Sauvain, Michael Riediker, Simon Deslarzes

Health effects of occupational traffic particle exposure

Collaboration with Wayne E. Cascio and Andrew J. Ghio, US EPA, USA

Exposure to particles as well as noise has been linked to myocardial infarction and ischemic heart disease. As highway maintenance workers spend most of their work time in traffic and are exposed regularly to particles and noise, they may be at higher risk for such cardiovascular diseases. The first aim of this study is to provide a better understanding of the workers’ exposure to particles and noise; the second aim is to investigate the health effects that are related to these two exposure types.

Staff involved: Michael Riediker, Reto Meier, Brigitta Danuser

Nanoparticle tracking and oxidative stress biomarkers in healthy non-smoking volunteers

Collaboration with Paul Bowen, Powder Technology Laboratories of EPFL

Nanoparticles (NPs) are being increasingly developed and manufactured for a variety of medical and technical applications due to their novel and tunable properties. However, their ability to translocate and their increased reactivity may also pose a health risk. Nanomedicine and nanotoxicology currently lack precise information about the actual deposited dose after inhalation of NPs, their fate in the human body and their ability to induce biological effects, such as oxidative stress. In this study we aim at better understanding the fate of deposited particles and the differences in oxidative stress response in volunteers exposed either to superparamagnetic iron oxide NPs (SPIONs) – mainly used in magnetic resonance imaging and drug delivery in cells – and cigarette smoke.

Staff involved: Michael Riediker, Jean-Jacques Sauvain, Elie-Jacques Fares, Nastassja Lewinski

Exhaled breath condensate (EBC) as a matrix for nanoparticle exposure and health effects evaluation

The aim of this pilot project was to evaluate the feasibility of assessing the deposited particle dose in the lungs by applying the dynamic light scattering-based methodology in exhaled breath condensate (EBC). In parallel, we developed and validated two analytical methods allowing the determination of inflammatory (hydrogen peroxide - H2O2) and lipoperoxidation (malondialdehyde – MDA) biomarkers in exhaled breath condensate. Finally, these methods were used to assess the particle dose and consecutive inflammatory effect in healthy non-smoker subjects exposed to environmental tobacco smoke in controlled situations was done.

Staff involved: Michael Riediker, Jean-Jacques Sauvain (past: Magdalena Sanchez: internship)

Characterization of Particulate Matter (incl. Nanoparticles) for the Life Cycle Assessment Methodology according to their Impact on Human Health

Collaboration with EMPA St. Gallen, ETH Zurich

Existing life cycle assessments of particulate matter typically define PM in very general terms (i.e., total mass of PM).  However, this evaluation of PM neglects its highly complex nature and variable health impacts. This project aims to develop a more refined description of particulate matter in life cycle assessments; one that better reflects PM’s contribution to adverse health effects than does mass alone.  Particular focus is given to factors such as particle size, particle number concentration, and particle composition and their effects on human health.

Staff involved: Michael Riediker (past: Katie Clark, Post-doc)

Cell-based sensing microsystem (LiveSense)

Collaboration with Philippe Renaud, Nicolaas De Rooij, Hubert Girault, EPFL, Jan van der Meer, UNIL, Martial Geiser, HESSO-VS/SI, Martha Liley, CSEM, Viola Vogel, ETHZ

The objective of the LiveSense project is the realization of a complete autonomous cell-based sensing microsystem which includes: a cell culture microbioreactor, the secondary sensors to measure cell response, the signal processing control unit and a wireless communication unit to link the microsystem to a sensor network. IST contributes expert knowledge regarding the user-needs and supports the teams regarding potential health and environmental questions.

Staff involved: Michael Riediker

Exposure characterisation and risk management

Solid-Phase Microextraction as Short-Term Sampling Technique for BTEX Occupational Exposure

The potential of SPME as alternative to convential method was confirmed. Charcoal tubes as air sampling method are generally insufficiently sensitive to allow the determination of the analytes in short exposures, and to comply with the new requirement of 15-minute TLVSTEL for benzene (8 mg/m3). In contrast, SPME technique with good calibration facilities using permeation device for individual fiber calibration can be succefully used for BTEX survey in occupational field and environmental studies. SPME technique has many advantages: sensitivity, simplicity, cheap, solvent-free, fast, short sampling time, no sample preparation and accuracy. However, the use of SPME fiber under non-equilibrium conditions required to determine the equivalent uptake rate of each individual fiber for every analyte of interest. A special care has to be taken over the influence of air velocity. But this latter is not so critical in normal calm air situations. In these conditions, SPME method for air sampling is a very sensitive technique allowing fulfilling the performance criteria required for 15-minute TLV-STEL for benzene.

Occupational exposure of parquet floor sander to polycyclic aromatic hydrocarbons (PAH) in the generated wood dust

Malignant naso-sinusalcavity (NSC) tumours represent approximately 3% of ORL cancers. NSC adenocarcinomas an occupational disease acknowledged in certain specialist workers such as joiners and cabinet makers. Great Britain in 1969 and France in 1981 recognize its professional aetiology based on statistical observations. The high proportion of woodworkers contracting a NSC adenocarcinoma, subjected to an estimated risk 50 to 100 times higher at that affecting the general population, has suggested various study paths to some possible causes, such as the tannin in hardwood, formaldehyde in plywood and benzo(a)pyreneproduced by overheated wood by cutting tools. Specific tasks, such as sanding, cause the emission of fine dust, which can remain in suspension in air for many hours in badly ventilated locations. These hypotheses have not been confirmed to date by practical measurements, and the issue remains open. It is acknowledged that tannin does not cause cancer under exposure to tea dust. Formaldehyde is an irritant, but it is also classed carcinogenic. The path involving carcinogenic Polycyclic Aromatic Hydrocarbons (PAH) emitted by overheated wood is attractive. In this study, we have studied their content in relation to operations performed on wood in an experimental chamber and we have measured the particle size of the generated dust.

The wood dust contains carcinogenic PAH at the level of g/g or ppm. The PU canish-impregnated wood produces 100 times more PAH than the unfinished wood during sanding operations. The woodworking tools such as sander, circular saw or plane create dusts with particle size distribution centred around 10mm or more, thereby resulting in a prevailing dust deposit of dust in the naso-sinusal cavity and less in the lung. Swiss regulated TLV of 2mg/m³ of inhaled dust would appear to protect effectively workers, as long as PAH contents do not exceed the ppm level. The PAH are produced by excessive heating of the sanding or cutting tools at the surface level of the wood which induces a partial combustion of the organic matter in wood or the PU varnish. There are no notable difference in PAH content of tender wood (fir tree) and hard wood (oak).

It is important that the concerned workers are aware of the danger of wood dust exposure and that they adopt adequate protection measures, such as wearing a dust protection mask or workshop ventilation. Tools fitted with dust collection bags produce less airborne dust and contribute to a better protection. Coud the presence of PAHs in wood dust be a cause of adenocarcinoma in joiners and cabinetmakers? Additonal investigations are necessary to better determine the woodworker exposure to the PAHs and its health effects.

Indoor Air Quality in a Public Building following Smoking Bans

Indoor air quality in a university large building of 450’000 m3 of total volume was studied before and a smoking ban had been applied. Several selected environmental tobacco smoke (ETS) tracers were used during this study: total dust, condensate, polycyclic aromatic hydrocarbons (PAHs) monitor and nicotine. Measurements of real time monitors were collected with data-logging instrumentation. Before the decision to ban smoking in June 2004, the level of the concentrations of dust was higher, with a daily average of 320 μ g/m3, range 80-1000 μ g/m3 and peaks of more than 1000 μ g/m3, compared with outdoor air values, mean 22 μ g/m3, range 22-30 μ g/m3 . For the condensate, the mean was 96 μg/m3, range 37-224 μg/m3 before. The nicotine level is definitely more important before, mean 5.53 μ g/m3, range 1.5-17.9 μ g/m3. Once the smoking bans inside the building were applied, beginning in October 2004, we observed a clear improvement in terms of concentrations of pollutants. For dust, the concentration fell by 3 times, mean 120 μ g/m3, range 40-160 μ g/m3, for condensate 2 times, mean 57 μ g/m3, range 30-100 μ g/m3, and that of the nicotine by 10 times, mean 0.53 μ g/m3, range 0-1.69 μ g/m3 compared to that found before the smoking bans.

This confirms that the indoor pollution observed has cigarette smoke as its origin. Nicotine is proposed as the best tracer for indoor air quality monitoring against pollution by ETS.

Laboratory Generated Bitumen Fumes Under Standardized Conditions

Clean-up Scheme and Ion Trap GC-MS Analysis of VOC, Semi-Volatile and Particulate PAH and PASH

This project aims at evaluating the applicability of an efficient clean-up and enrichment procedure for the determination of polycyclic aromatic compounds (PAC) including polycyclic aromatic hydrocarbons (PAH) and polycyclic aromatic sulfur heterocyclic hydrocarbons (PASH) in the gas and particulate phases in raw bitumen and bitumen fumes by gas chromatography-ion trap mass spectrometry. The scheme includes a liquid-liquid partition to eliminate the aliphatics, a solid phase extraction on SiO2 cartridge to remove the polar compounds and an HPLC fractionation to isolate the aromatic fraction. The purified extract enables the determination of PAH profile from 2 to 7 rings including their methyl derivatives and 3 carcinogenic benzonaphthothiophene isomers. The reproducibility of the method was estimated by analyzing 6 bitumen replicates and is around the 30% overall uncertainty or less. In bitumen fumes generated at 170°C under standardized conditions, VOC and semi-volatile PAH were sampled with XAD-2 tubes and were also determined in six replicates. The VOCs are mainly monoaromatic derivatives (4% of fumes) and aliphatics essentially from C6 to C17 (27%). With regards to the particulate phase PAC, the coefficients of variation from 6 replicates are 5-24 % for PAH and 6-10% for PASH. Data on VOC and PASH represent new contribution in the characterization of bitumen fumes.

Identification and quantification of PAH in bitumen by GC-ion trap MS and HPLC-fluorescent detectors

Bitumen is a complex product with a large matrix of heavy aliphatic/naphthenic/aromatic hydrocarbons as well as a large number of isomeric compounds such as polycyclic aromatic compounds (PACs). Some PACs and derivatives are known to have a mutagenic and carcinogenic activity, and there is no generally satisfactory clean-up method for separating PACs from this very complex hydrocarbon matrix. Moreover, from an analytical point of view, the isomeric compounds usually co-elute in the same gas chromatography (GC) retention range, GC being one of the most widely used techniques in this area. However, the use of a suitable clean-up procedure for isolating the aromatic fractions, combined with two selective detection techniques such as mass spectrometry (GC-Ion Trap MS) and HPLC-Florescent detector (HPLC-FL), is expected to provide an effective tool for accurately determining certain PAC species in bitumen.

Occupational exposure to mineral oil Metalworking Fluid (MWFs). Mist: development of new methodologies for mist sampling and analysis

Metalworking Fluids (MWFs) are largely used in the sector of undercutting, a large professional activity in Switzerland, in particular in the fine mechanic and watch making industry. France proposes a permissible exposure limit (PEL) of 1 mg/m3 of aerosol. The American Conference of Governmental Industrial Hygienists (ACGIH) sets its value at 5 mg/m3 but a proposal to lower the standard (“intended changes”) to 0.2 mg/m3 of aerosol is pending since 2001. However, it has not become a recognized threshold limit value for exposure. Since 2003, the new Swiss PEL (MAK) recommendations would be 0.2 mg/m3 of aerosol (oil with boiling point > 350°C without additives) and/or 20 mg/m3 of oil aerosol + vapour.

To evaluate evaporative losses of sampled oil, the German Berufsgenossenschaftliches Institut für Arbeitssicherheit (BGIA) recommends the use of a XAD-2 cartridge behind the filter. The method seems to work perfectly for MWFs in a clean occupational atmosphere free from interference of light vapour cleaning solvent such as “White Spirit”. Yet, in machine shops atmosphere contaminated with traces of White Spirit, the BGIA method failed to estimate the MWFs levels (overestimation). In this project, we propose a new approach meant to measure both oil vapours and aerosols. Inter-laboratory comparisons will be organized, based on the production of oil mist in an experimental chamber under controlled conditions.

OHBaP by HPLC-Column Switching

IST has been interested in the analysis of polycyclic aromatic hydrocarbons (PAH) for many years because of their potential carcinogenicity. These substances are found in many workplaces such as coke ovens, aluminium plants, during paving roads activities. In the human body PAH are oxidised and partly eliminated in the urine in a hydroxylated form. Urinary 1-hydroxypyrene (1-OHP) has been widely used as a biomarker of exposure to PAH. However, neither pyren nor its metabolites are carcinogens and their presence is not a proof of exposure to carcinogenic hydrocarbons. Benzo[a]pyren (BaP) is known to cause cancer; after metabolisation, it is eliminated in the form of two isomers, 1 and 3-hydroxybenzo[a]pyrene (1 and 3-OHBaP). The analysis of PAH mixtures is commonly done by HPLC-FL, but an efficient separation of 1 and 3-OHBaP is problematic as they elute together. The project aimed at building an HPLC switching system and analyse 3-OHBaP in urines of smokers and possibly non-smokers. The switching system has been ultimated and it can be applied to any HPLC system, and of course, to the LC-MS/MS facility.

Analysis of urinary PAHs metabolites by HPLC-FL and LC-MS/MS

IST has been interested in the analysis of polycyclic aromatic hydrocarbons (PAH) for many years because of their potential carcinogenicity. These substances are found in many workplaces such as coke ovens, aluminium plants, paving roads activities or passive tobacco smoke. It is thus clear that the analysis of PAH in the work environment and in the workers themselves (biological monitoring) is of primary importance. In the human body PAH are oxidised and partly eliminated in the urine in a hydroxylated form. The oxidised forms of some PAH are carcinogenic as they can fit in the base pairs of DNA double helix and bind to it. As pyrene is very often present in PAH mixture, its metabolite 1-hydroxypyrene (1-OHP), which is excreted in urines, has been used several times as a biological indicator of exposure to PAHs. However, nor pyrene nor its metabolites are carcinogens and their presence is not a proof of exposure to carcinogenic hydrocarbons. Benzo[a]pyrene (BaP) is known to cause cancer; after metabolisation, it is eliminated in the form of two isomers, 1 and 3-hydroxybenzo[a]pyrene (1 and 3-OHBaP). It seems that the second metabolite is the most carcinogenic form so that the analysis of this isomer is very important for proving a workplace dangerous for the workers’ health. 3-OHBaP is present in the human urine in quantities near the limit of detection of the most usual analytical techniques so that great care must be given to the choice of the extraction method in order to recover the most part of the analytes.

Aims

The objectives of the present research project are to evaluate PAHs urinary metabolite levels (particularly the 1-hydroxypyrene (1-OHP), 6-hydroxychrysen (6-OHC), 1- and 3-hydroxybenzo(a)pyrene (1- and 3-OHBaP)) in few urine samples, from smokers and non-smokers, occupational PAHs exposed and non-exposed workers.

Methods

• Develop a quantitative method to characterize the PAHs urinary metabolites by HPLC-FL and LC-MS/MS, particularly the 1-hydroxypyrene (1-OHP), 6-hydroxychrysen (6-OHC), 1- and 3-hydroxybemzo(a)pyrene (1- and 3-OHBaP).
• Confirm by LC-MS/MS the presence of 1-OHP and OHBaP in human urine.
• Development of extraction techniques, clean-up scheme, recovery studies : SPE cartridges, Liquid-liquid extraction and “Blue-Rayon” (copper phthalocyanine) enrichment.
• Apply the method to evaluate PAHs urinary metabolite levels in few urine samples, from smokers and non-smokers, occupational PAHs exposed and non-exposed workers.

Expected results

This work should contribute to the validation of a new analytical method for the urinary PAHs metabolites as a tool to evaluate the occupational exposure to the carcinogenic members of the PAHs family.

“Comet Assay”, in vitro testing and in vivo application

Single cell gel (SCG) electrophoresis or “Comet assay” is a rapid and very sensitive microscopic method to examine DNA damage and repair at individual cell level. Actually, the comet assay has become one of the standard methods for assessing DNA damage, with applications in genotoxicity testing, human biomonitoring and molecular epidemiology, as well as fundamental research in DNA damage and repair. The assay is attractive because of its simplicity, sensitivity, versatility, speed, and economy.

The first objective of the present project is to develop and validate the comet assay on finger-prick blood samples.

The final goal is to screen a wide variety of occupational situations to evaluate the DNA damaging risk in relation with other air and biomonitoring indicators.

Mercury exposure assessment associated with gold mining activities

Artisanal gold-mining activities are in full rise in Burkina Faso with about 200 active sites spread in the entire country. The mining process involves the extraction of gold from the ore by mercury amalgamation, followed by roasting the resulting product to vaporize mercury out of the amalgam. A health survey was conducted among the working population of several sites by the OST. As part of this survey, biomonitoring was used to assess mercury exposure in the various mining sites, and associated with the various activities. Mercury excretion in urine was used as indicator of current exposure.

Methods

Forty-six subjects associated with gold mining activities in 5 sites participated in this pilot study. Biomonitoring was performed by mercury determination in spot urine samples collected before shift in a metal-free polystyrene flask. Samples were frozen at -20°C the same day and delivered in a cold state to the IST laboratory in Switzerland. Analysis was carried out by cold vapour atomic absorption spectrometry for mercury, and colorimetry for creatinine. Occupational history and medical status were assessed by local medical personnel using a standard questionnaire.

Results

From the 46 urine samples collected, 31 came from “unrefined gold” dealers (group A) who are also doing amalgam roasting, 13 from workers involved in ore washing and the amalgamation process (group B), and 2 from workers concerned with crushing, brinding and washing stages (group C). Urinary mercury excretion ranged from 5 to 1707 mg/g creatinine with a global average of 146 mg/g. Seventy percent of the urinary results are above the BEI of 35 mg/g creatinine recommended by ACGIH. Mean urinary concentrations were respectively for each group A, B, and C of 204, 28.7 and 15.6 mg/g, indicating a very high exposure for “unrefined gold” dealers due to their roasting activity. Analysis of the results by sites shows a very high variability with averages by sites ranging from 26.1 mg/g up to 298.8 mg/g.

Results obtained can be used to target prevention programs and activities in order to reduce mercury exposure in the concerned population.

Biological monitoring of occupational exposure.

Toxicokinetic differences due to age and gender

Biological monitoring is a widely used method among occupational physicians to estimate chemical exposure. Recommended biological limits are published periodically in Switzerland and in other countries for interpretation and decision-making. A large variability is associated with biological monitoring, making interpretation less efficient than foreseen. In order to improve applicability of biological monitoring, specific factors responsible for this variability should be identified and their contribution quantified. Among these factors, age and gender are easily identifiable, and present knowledge about pharmaceutical chemicals suggests that they play an important role on the toxicokinetics of occupational chemical agents, and therefore on the biological monitoring results.

The objective of the present research project is to quantify the influence of age and gender on biological levels of some important chemicals and their metabolites in the human body. This will be done experimentally, by observation, and by toxicokinetic computer simulation.

Controlled human exposures to methyl ethyl ketone (MEK), 1,1,1-trichloroethane, styrene and propylene glycol monomethyl ether (PGME) will be performed in an exposure chamber and the kinetics of the parent compounds (organic volatiles) and their metabolite(s) followed in blood, urine and expired air over time. Extrapolation to other chemicals will be done by physiologically based pharmacokinetic (PBPK) models and by compartmental toxicokinetic (TK) models after validation.

The proposed project will improve our understanding of the influence of age and gender on biological indicators of exposure. It is expected that the results obtained will make it possible to improve recommended limits and the associated decision process to avoid undue costs and unacceptable risks to the employees.

Occupational health: molecular approaches to assess risk of bioaerosol exposure in workplaces

The presence of micro-organisms (bacteria, fungi and their by-products) in the work environment may compromise the quality of work material and/or the health and well being of the exposed workers. There are many occupations, which involve the handling of organic matter, and this may be an optimal medium for multiplication of microorganisms. Some populations of workers are, therefore, exposed to high levels of airborne microorganisms, which have been recognised as a cause of respiratory symptoms. In particular, inhalation of endotoxins (a toxic component of the cell wall of Gram-negative bacteria) is associated with many symptoms such as acute airway obstruction, a decline of pulmonary function, acute fever, extrinsic allergic alveolitis, chronic bronchitis and organic dust toxic syndrome.

Traditional culture-dependent methods to quantify and identify airborne microorganisms are limited by different factors (short-duration sampling times, difficulties in personal sampling and inability to enumerate non-culturable or non-viable bacteria). Consequently, assessment of bioaerosols is often underestimated. With the advent of PCR technology it is now possible to overcome these limitations. The goal of this project is to focus our research on a molecular approach to assess and monitor bioaerosol exposure at work in respect to their health effects. This will include the setting up of new experimental designs, the development of robust identification protocols (including the detection of specific airborne micro-organisms using DNA analysis), the use of PCR for bioaerosol quantification and monitoring (quantitative PCR). This study will be the only project involving a molecular approach to bioaerosol analysis and occupational health in Switzerland. Results could improve quality of life and reduce health costs.

Application of real-time PCR method for total airborne bacterial assessment, comparison with epifluorescence microscopic method

Traditional culture-dependent methods to quantify and identify airborne microorganisms are limited by different factors (short-duration sampling times, inability to enumerate non-cultivable or non-viable bacteria). Consequently, the assessment of bioaerosols is often underestimated. To overcome this problem, the real-time quantitative polymerase chain reaction (real-time Q-PCR) has been used to quantify bacteria in environmental samples. The aim of this study was to evaluate the performance of a real-time Q-PCR method to quantify the bacterial load in indoor air of poultry houses and sewage treatment plants and to compare it with epifluorescence microscopy (collaboration with INRS, P. Duquenne) and culture-dependent methods.

Quantification of biological variability. Contribution of air exposure variations

The objective of the present project is to document and quantify the contribution of variability of air exposures to the total variability observed in biological indicators. The objective is also to propose a mathematical model to describe total variability in biological monitoring by including the different sources of variability.

Compartmental and PBPK models are used together with a priori distributions of physiological and metabolic parameters, and distributions of exposure levels to estimate variability in 30 biological indicators. Results obtained are presented in a form which can be helpful for practitioners to interpret biological monitoring results.

The present research in carried out in collaboration with University of Montreal and the IRSST of Quebec.

Biological monitoring for the evaluation of occupational health risks for workers exposed to fungicides in arboriculture

Arboriculture represents about 20% of the agricultural activity in Valais. Fruit trees undergo numerous fungicides treatments despite ecological requirements. Captan and Folpet, two important fungicides, are used for treatment in spring and in autumn. Potential dermal, oral and respiratory exposure of workers can occur during these treatment.

The objective of the present research is to develop a toxicokinetic model in order to establish reference biological values for Captan and Folpet. The model should describe the parent compound and its metabolites in the human body.

Three aspects are considered in this research: exposure of human volunteers, development of a toxicokinetic model, field investigations in exposed workers including urine and blood measurements of metabolites and exposure (dermal, inhalation) investigations.

The biological monitoring tools developed here will serve to better assess the exposure of workers to Captan and Folpet under various circumstances. Extrapolation to other fungicides will also be considered for application.

Emission factors integrated method for airborne pollutants assessment at workplaces

The proposed project aims, by providing adequate tools for the practitioners (OH&S specialists), to improve the conditions in which the “expert judgments” take place. It is assumed that, an implementation of the existing models with emission and near-field considerations may not only enhance significantly the tools itself but also the overall expert judgement performance.

In a first step a survey was made among professionals to better define their expectations about modelling tools (what types of results, models and potential observable parameters).

Experimental and modelling work was performed in some specific cases to identify difficulties with existing tools. Further exposure to waterproofing sprays was studied as part of an epidemiological study on a Swiss cohort.

Experiments were then carried out in 2 experimental chambers to better understand the processes of emission and dispersion for tracer compounds. In a further step the experimental data were completed by observations made in about 100 different workplaces, including exposure measurements and observation of predefined determinants. The various data obtained have been used to improve an existing two-compartment exposure model.

Evaluation of chemical exposure: combining exposure measurements and determinants to make better decisions

Occupational exposure to chemicals is influenced by numerous factors associated with characteristics of the workplaces and activities of the workers. In most cases exposure is estimated by direct measurements of air concentrations or of levels in biological fluids. An other approach consists of predicting exposure with physical models of emission and dispersion, taking into account some exposure determinants. Still an other approach would consist in a Bayesian combination of the 2 types of results (measurements and determinants). This combination would allow generally a reduction of the variability associated with direct occupational exposure measurements. This would make decision more efficient when comparing results with occupational exposure limits for example.

The present research project proposes to integrate exposure a priori with direct measurements in order to reach a better estimation of past (epidemiology) and current exposure (surveillance). A Bayesian integration framework will be developed based on existing exposure data. This research consists of the following parts:

• Identification of existing exposure data in France and Switzerland, taking into account not only exposure itself but also the availability of exposure determinants,
• Processing of existing data following the norm EN 689 in order to put every chemical agent on the same scale
• Building of empirical models using neuronal networks to integrate information on exposure determinants,
• Application of Bayesian statistics to combine direct measurements and information of determinants, to reduce estimation uncertainty,
• Development of a strategy for decision making on the combined information.

This approach has already been tried at several occasions for the retrospective estimation of occupational exposure to chemicals, in one case by one of our research groups. It has however not yet been considered for current or prospective occupational exposure estimation. The decision making strategy presently used in occupational health is described in the norm EN 689. Present research work tends to integrate this strategy, notably decreasing variability of exposure assessment.

Occupational exposure database

Assessment of occupational exposure to chemical and physical agents is often done based on an “expert judgment” in Switzerland. A database is created with actual measurements in order to help practitioners. Direct measurements are costly and when done they should be shared between professionals so that more then one situation benefit from them.

Exposure measurements done by IST and other partners are stored in a database according to the format recommended by international experts. Apart from measurement of specific variables, the type of industry (NOGA) and of profession (OFS) are recorded. The database is accessible online on www.i-s-t.ch and can be search either by NOGA, OFS or danger (chemical, physical, biological). It contains (2007) more than 10’000 records.

It is expected that data form other Swiss institutions than IST will be available in the database shortly. The format of the database has been updated to include physical contextual determinants. This is an ongoing project.

Occupational skin exposure to chemicals. Towards an improved skin notation

The Skin Notation, indicating possible uptake via the skin, are based on varying databases and assumptions.

Both, the fact that they vary from country to country, and the number of chemicals notified with a Skin Notation (1/3 of the OEL list) indicate the unsatisfactory of the criteria and databases used for their establishment.

The objectives are to propose qualitative criteria to characterize the risks of the different chemicals for the skin and to propose quantitative criteria for the establishment of a reliable Skin Notation to be applied to the entire OEL list.

Preliminary contacts with the Swiss OEL Committee have shown a clear interest for a collaboration and the OEL Commission is expected results for the 2009 edition of OEL.

Assessing UV exposure: measurements and prediction of individual exposure

Excessive exposure to solar UV light is the main cause of skin cancers in humans. Factors such as the increase of solar irradiation at ground level, the rise in standard of living and the development of outdoor activities have contributed to increase exposure. Thus, unsurprisingly, incidence of skin cancers has increased over the last decades more than that of any other cancer. Switzerland is among the European countries the most affected by this public health problem.

UV exposure depends on ambient irradiation level and individual factors related to activity (position to sun, clothing, duration of exposure, other forms of sun protection). The risk of skin cancer varies according to the skin type and the exposure of anatomical parts of the body. The neck, shoulders and head are usually the most irradiated parts.

This research project aims at developing and validating a predictive tool of individual exposure to solar UV. Exposure levels of body parts will be predicted on basis of ambient irradiation levels and information about postural activity. The tool will use existing techniques in the field of 3D numeric simulation and will be validated against individual dose measurements.

The use of a numeric method should facilitate assessment of individual exposure and allow predictive scenarios (either prospective or retrospective). In the long run, a better quantification of exposures for specific occupational and leisure activities should assist in better targeting preventive actions.

Strategy development for retrospective exposure assessment

Most of the time, exposure assessment in occupational hygiene and ergonomic is prospective. In epidemiology and in patient’s exposure assessment, qualitative and quantitative tool are require to study past exposures.

The first objective of the present research is to develop strategies and tools for retrospective exposure assessment of patients presenting identified and developed pathologies. This project relies on systemic investigations of cases presented to the out-patient clinic of IST. A second objective is to make recommendation for improvement of workplaces to avoid further cases.

This research is based on the following methodologies: interview of patients, co-workers and supervisors, observation of work-processes, modelling of past exposures, measurement of reconstructed exposures.

For each case studied, a short report is made to the occupational physician and the employer (when applicable). Cases will be review and discussed in a general scientific report aimed at establishing an investigation strategy.

Cutaneous resorption of chemicals : Creation of a quantitative tool for risk analysis

The main purpose of the current project is to propose a computer-based tool that will help IH professionals identifying situations where the dermal exposure pathway might increase the health risk posed by a chemical substance. This tool will provide a quantitative and systematic alternative to the traditional skin notation.

Several approaches have been described in the literature that compared internal dose or blood levels of a chemical caused by dermal exposure to those caused by inhalation at the OEL. Based on these methods, we intend to create quantitative indices measuring the relative contribution of the dermal pathway to total internal dose. Existing OELs will be used to derive internal reference doses. Several indices will be created to allow for a variety of exposure scenarios, including different combinations of dermal exposure duration and proportion of body surface exposed. The calculation of the indices requiring values of transdermal penetration constants, they will be estimated using already available and validated quantitative structure-activity relationships (QSAR). All necessary physico-chemical constants and toxicological values for the substances in the Swiss OEL list have already been formatted into a database during a related research project at IST. The created approach will take the form of a decision tree guiding the user through the scenario selection process to the final index calculation. The procedure will be implemented in the form of a software available through download at the IST internet website.

This project will lead to the availability to IH professionals of a computer-based tool for assessing the contribution of the dermal exposure pathway to the overall risk posed by chemicals in the workplace. This should improve the specificity in selecting situations requiring detailed dermal exposure assessment.

Psychosocial factors

Cardiorespiratory Reactivity, Visual Attention and Metabolic Balance During Affective Picture Viewing

Picture series of different contents were shown to 41 young adults while cardiorespiratory parameters, skin conductance, spontaneous eye-blinking and judgments of valence and arousal were recorded. The analyses reveal several relationships between self-rated valence and arousal and the physiological measures which extend and enrich our knowledge of emotional processing.

Médecins pour médecins: une antenne au service de la santé des médecins

Médecins pour Médecins est un projet d’entraide pour les médecins en difficulté, inspiré des connaissances en médecine du travail. Il comprend en particulier la mise sur pied d’une antenne téléphonique avec capacité d’accueil, d’écoute et de conseil par un médecin. Appuyé par un réseau de thérapeutes de toute la Romandie prêts à recevoir un collègue, l’antenne sera à même de proposer un choix de prise en charge spécialisée en fonction du problème évoqué.

Le projet a aussi pour ambition de proposer un pool de médecins pour des remplacements urgents en cabinet, et de promouvoir une culture de santé au travail au sein de la corporation médicale, avec une remise en questions de certaines tendances défavorables inhérentes à sa tradition et à un système de croyances bien ancré.

Réinsertion professionnelle des opérateurs absents pour cause de troubles musculosquelettiques dorsaux

Les troubles musculosquelettiques sont des pathologies multifactorielles. Des facteurs de risque, tant psychosociaux (insatisfaction au travail, manque de reconnaissance et de soutien social, insécurité de l’emploi), qu’organisationnels (manque d’autonomie, pression tempo­relle, répartition des tâches) et biomécaniques (répétitivité, postures contraignantes) sont en cause. Pour favoriser le retour au travail d’opérateurs absents suite à ce type de pathologie, une intervention sur l’individu et sur les conditions de travail est indispensable.

Un programme intensif de rééducation, axé sur l’activité professionnelle, a été organisé pour restaurer les capacités fonctionnelles et professionnelles de l’individu. Parallèlement, une ana­lyse ergonomique de la situation de travail permettra une adaptation des conditions de travail. Plu­sieurs outils utilisés lors de l’analyse ergonomique du travail (Siegrist, Karasek) mettent en évidence des corrélations entre les facteurs psychosociaux et le développement de patho­lo­gies, dont les troubles musculosquelettiques.

Nuisance

Effects of F.M. Alexander Intervention on subjective and cardio-respiratory measures during daily activities – a pilot study

Scientific research on the psychophysiological effects of the F:M. Alexander Technique are scant. Put simply, the Technique is a means to re-educate how we use ourselves in our everyday life. By becoming more aware of the habits that tend to drive our lives we can learn to make conscious decisions both about how we organize our physical selves when lifting, speaking, handling objects, sitting etc. and in how we react to the stimuli that we meet during our every waking moment. This pilot study investigates how cardio-respiratory parameters and subjective feelings of nine adults are modified by a brief intervention with the F.M. Alexander Technique while sitting and standing both with and without the help of a trained person.

Music performance anxiety in professional music students

This study aims to determine if music performance anxiety (MPA) is physiologically associated with specific correlates of breathing disturbance and hyperventilation and to determine how tightly response systems (affective experience, self-perceived physiological activation, actual physiological activation) are coupled in MPA. Further, it surveys the occurrence, experience, and management of MPA. The findings will permit to reject or support a theory of anxiety that postulates that increased levels of peripheral physiological responding always co-occur with higher levels of anxiety experience and higher levels of self-perceived physiological symptoms. This research will also have consequences for the use of ambulatory monitoring of respiration as an additional tool for the diagnostic assessment and the therapy outcome assessment of anxiety as well as implications relating to the development and implementation of treatments for MPA.