Estimates Of Occupational Exposure Research Articles

Assessment of the suitability of selected non-measuring models for dermal exposure estimation for the purposes of assessing compliance of working conditions with restrictions 71 and 76 in Annex XVII of the REACH regulation

Occupational exposure to chemicals occurs mainly through inhalation and the skin. The inhalation exposure assessment is regulated by law, while in Poland the method of conducting measurements for dermal exposure has not been indicated in the law. However, due to the restrictions 71 and 76 from Annex XVII of REACH for 1-methyl-2-pyrrolidone (NMP) and N,N-dimethylformamide (DMF), exposure assessment by the dermal route is necessary. These restrictions require to ensure that exposure of workers is below the derived no-effect levels (DNELs) for dermal exposure. The aim of the work was assessment of suitability of selected non-measurement forecasting models for the estimation of dermal occupational exposure to chemicals for the purposes of assessing compliance of working conditions with the restrictions 71 and 76 of the REACH regulation. Three tools estimating dermal exposure, recommended by European Chemical Agency (ECHA), were selected: ECETOC TRA, RISKOFDERM and IH SkinPerm, which were used to estimate 2 exemplary workplaces. Results of the estimations of dermal exposure showed that non-measuring models are useful for fulfilling the obligations under restrictions 71 and 76 of Annex XVII of REACH. The type of exposure scenario and amount of data available for the workplace are crucial for the selection of the model. The ECETOC TRA was considered the best model for this type of analysis, whose main advantages are direct comparison of the output data in mg/kg/day with the DNEL value and use of standardized descriptors system. Exposure modeling is a good and cheap way to determine the dermal exposure magnitude at workplaces, also to comply with the requirements of restrictions 71 and 76 of Annex XVII of REACH. The application of modeling in the case of occupational exposure by the dermal route is one of the solutions when it is necessary to comply with the DNEL for dermal exposure. Med Pr Work Health Saf. 2023;74(6):487-500.

Estimation of inhomogeneous occupational exposure to the lens of the eyes and the extremities of radiation workers in a research accelerator facility.

We performed an experimental investigation on occupational exposure of the eye lens and the extremity of radiation workers engaged in handling of highly activated materials in a small research accelerator facility. Using a simplified physical phantom to simulate the relevant inhomogeneous radiation exposure situations, the personal dose equivalents obtained at the eye lens and the extremities of radiation workers handling heavily radioactive converters were measured together with the dose measured by personal dosemeters worn on their trunk. Results of mockup experiments and the Monte Carlo calculations suggest that the quantitative estimation of the eye lens doses can be estimated from the trunk dose, while the extremity doses vary considerably from the dose readings from the trunk, depending on the use of simple point-source or volume source geometry.

Job exposure matrices for occupational respiratory disease: a narrative review.

Job exposure matrices (JEMs) are epidemiological tools used to provide estimations of occupational exposures when it is not feasible to complete detailed individual occupational histories. To identify and summarize the characteristics of published general population JEMs (GPJEM) of inhalable occupational exposures applied in studies of respiratory disease. MEDLINE and EMBASE databases were searched using pre-defined search terms, with screening performed by two independent reviewers to identify studies reporting the use of a GPJEM. JEM creation papers were subsequently identified and reviewed for each individual GPJEM, noting its characteristics in terms of occupational classification system and exposure estimates. From 728 studies identified in initial searches, 33 GPJEMs of inhalable occupational exposures were identified. Versions of the International Standards Classification of Occupations were the most used occupational classification system. Binary, probability and intensity-based exposure estimates were most frequently reported in GPJEMs. Selection of a GPJEM to apply in epidemiological research should be based on the exposure(s) of interest, time period of occupations under review, geographical region for intended use, occupation classification system used and the exposure estimate outcome.

Development of a quantitative North and Central European job exposure matrix for wood dust.

Wood dust is an established carcinogen also linked to several non malignant respiratory disorders. A major limitation in research on wood dust and its health effects is the lack of (historical) quantitative estimates of occupational exposure for use in general population-based case-control or cohort studies. The present study aimed to develop a multinational quantitative Job Exposure Matrix (JEM) for wood dust exposure using exposure data from several Northern and Central European countries. For this, an occupational exposure database containing 12653 personal wood dust measurements collected between 1978 and 2007 in Denmark, Finland, France, The Netherlands, Norway, and the United Kingdom (UK) was established. Measurement data were adjusted for differences in inhalable dust sampling efficiency resulting from the use of different dust samplers and analysed using linear mixed effect regression with job codes (ISCO-88) and country treated as random effects. Fixed effects were the year of measurement, the expert assessment of exposure intensity (no, low, and high exposure) for every ISCO-88 job code from an existing wood dust JEM and sampling duration. The results of the models suggest that wood dust exposure has declined annually by approximately 8%. Substantial differences in exposure levels between countries were observed with the highest levels in the United Kingdom and the lowest in Denmark and Norway, albeit with similar job rankings across countries. The jobs with the highest predicted exposure are floor layers and tile setters, wood-products machine operators, and building construction labourers with geometric mean levels for the year 1997 between 1.7 and 1.9 mg/m3. The predicted exposure estimates by the model are compared with the results of wood dust measurement data reported in the literature. The model predicted estimates for full-shift exposures were used to develop a time-dependent quantitative JEM for exposure to wood dust that can be used to estimate exposure for participants of general population studies in Northern European countries on the health effects from occupational exposure to wood dust.

Loss to 5-year follow-up in the population-based Telemark Study: risk factors and potential for bias

ObjectivesThis study aimed to characterise participants lost to follow-up and identify possible factors associated with non-participation in a prospective population-based study of respiratory health in Norway. We also aimed to...

ECETOC TRAv3: An In-depth Comparison of Publicly Available Measurement Data Sets With Modelled Estimates of Occupational Inhalation Exposure to Chemicals.

In this study, 129 exposure situations (ESs) with six or more measured inhalation exposures to dust from solids or vapour from liquids in occupational settings were compared with modelled European Centre of Ecotoxicology and Toxicology of Chemicals (ECETOC) targeted risk assessment tool, version 3 (TRAv3) estimates. The measurement data were extracted from previously published studies examining TRAv3 performance and pooled into a curated database. The comparison exercise focussed on the vapour exposure scenarios, as there were too few dust scenarios for a meaningful analysis of any required model corrections. A group of experts in the exposure modelling field retrieved and reviewed the input parameters used in these ESs. Where considered appropriate, modifications were applied to better match the input parameter definitions and the scope of applicability of the TRAv3. Differences and mean absolute error (MAE) were calculated between the log-transformed modelled exposure value and the 75th percentile of each measured data set and regression analysis was performed. The results indicated that the TRAv3 overestimated 80% of the measured data sets. Both over- and underestimations were mostly by factors 1-5. The calculated MAE for liquids was 0.7, indicating that on average the difference between the 75th percentile and the TRAv3 estimate was less than one order of magnitude. A multiple linear regression showed that some input parameters such as medium volatility, certain process categories (PROC), industrial setting, and the presence of local exhaust ventilation are associated with underestimations. The results of the regression analysis can be used by TRAv3 users to review the degree of over- or underestimation in their current exposure assessments, compared to the curated database. Although multiple linear regression is an appropriate methodology to characterize the TRAv3's performance, more data sets are still needed in view of some remaining data gaps. Nevertheless, the results of the current analysis are being used by ECETOC to further develop the tool as a suitably conservative screening tool for use in REACH chemical safety assessment of occupational exposure to chemicals.

Occupational heat exposure and prostate cancer risk: a pooled analysis of case-control studies

Background and aim: Heat exposures occur frequently in many indoor and outdoor occupations. In our previous work, we observed some evidence for a positive association of occupational heat exposure and breast cancer risk. Here we seek to examine potential associations with prostate cancer risk in a large multi-country study. Methods: We performed a pooled analysis of data from 3,175 histologically confirmed prostate cancer cases and 3,529 frequency-matched controls from studies in three different countries, Spain, France, and Canada. The Finnish job exposure matrix, FINJEM, was used to apply estimates of occupational heat exposure to the lifetime occupational history of participants. Three main exposure indices were used: ever vs. never exposed, lifetime cumulative exposure (heat stress years) and duration of exposure (years) with a lag period of 5 years. We estimated odds ratios (ORs) and 95% confidence intervals (CIs), using conditional logistic regression models stratified by 5-year age groups and study and adjusted for potential confounders. Results: A total of 32% of cases and 33% of controls were classified as being ever occupationally exposed to heat. Highest heat exposed occupations included ore and metal furnace operators, firefighters, and bakers. We found no evidence for an association of ever occupational heat exposure and prostate cancer risk (OR 0.92; 95% CI 0.83, 1.03). There were also no associations observed in the highest categories of lifetime cumulative exposure or duration, and there was no evidence for a trend. Results did not change when stratifying by Gleason scores. When analysing the Spanish case-control study separately using a Spanish job exposure matrix developed for local working conditions, some odds ratios were elevated, though results were imprecise. Conclusions: Findings from this pooled study have provided no strong evidence for an association between occupational heat exposure and prostate cancer risk. Keywords: prostate cancer, occupational exposures, heat, pooled analysis

Asbestos Exposure in Patients with Malignant Pleural Mesothelioma included in the PRIMATE Study, Lombardy, Italy.

The PRIMATE study is an Italian translational research project, which aims to identify personalized biomarkers associated with clinical characteristics of malignant pleural mesothelioma (MPM). For this purpose, characteristics of MPM patients with different degrees of asbestos exposure will be compared to identify somatic mutations, germline polymorphism, and blood inflammatory biomarkers. In this framework, we assessed exposure to asbestos for 562 cases of MPM extracted from the Lombardy region Mesothelioma Registry (RML), for which a complete interview based on a standardized national questionnaire and histopathological specimens were available. Exposure assessment was performed: (1) through experts' evaluation (considered as the gold standard for the purpose of this study), according to the guidelines of the Italian National Mesothelioma Registry (ReNaM) and (2) using a job-exposure matrix (SYN-JEM) to obtain qualitative (ever/never) and quantitative estimates of occupational asbestos exposure (cumulative exposure expressed in fibers per mL (f/mL)). The performance of SYN-JEM was evaluated against the experts' evaluation. According to experts' evaluation, occupational asbestos exposure was recognized in 73.6% of men and 23.6% of women; furthermore, 29 men (7.8%) and 70 women (36.9%) had non-occupational exposure to asbestos. When applying SYN-JEM, 225 men (60.5%) and 25 women (13.2%) were classified as occupationally exposed, with a median cumulative exposure higher for men (1.7 f/mL-years) than for women (1.2 f/mL-years). The concordance between the two methods (Cohen’s kappa) for occupational exposure assessment was 0.46 overall (0.41 in men, and 0.07 in women). Sensitivity was higher in men (0.73) than in women (0.18), while specificity was higher in women (0.88) than in men (0.74). Overall, both methods can be used to reconstruct past occupational exposure to asbestos, each with its own advantages and limitations.

Dose estimates of occupational radiation exposure during radioguided surgery of Tc-99m-PSMA-labeled lymph nodes inrecurrent prostate cancer.

[99mTc]Tc-PSMA-based radioguided surgery (TPRS) represents a curative approach for localized relapse of prostate cancer. For its simplified regulatory permission, the radiation protection authorities require a 99mTc- activity below the exemption limit of 10 MBq at the time of surgery. Our aim was to determine the optimal amount of radioactivity (OAR) to comply with that limit and to estimate the maximum number of TPRS procedures per year and surgeon without triggering the full monitoring obligations. In this retrospective study, a dose rate meter was calibrated using measurements on phantoms and from recently injected (1 min p. i.) patients to determine the activity in the patient from measured dose rates. The effective half-life of 99mTc-PSMA-I&S in patients was determined from repeated dose rate measurements to estimate dose parameters of relevance for radiation protection. External exposures of the surgeons were measured with personal dosimeters calibrated in Hp(10). The surgeon's finger dose Hp(0.07) is estimated from radioactivity measured in resected lymph nodes. Potenzial incorporations were estimated for an activity of 10 MBq. From the first 6 subsequent patients, an effective half-life of 4.15 h was observed. Assuming an operation time 24 h p. i., the OAR was 550 MBq. Operations lasting in average 2 h in a distance of 0.25 m to the patient imply a body dose for surgeons of 4.16 µSv per procedure. Based on these estimates, the surgeon's Hp(10) is less than 1 mSv per year with up to 241 operations per year. Hp(0.07) and potential incorporation of activity do not lead to further limitations. All radiation protection regulations are met with adherence to OAR recommended here without triggering the full monitoring obligations from radiation protection regulations.

The prevalence of occupational exposure to noise: A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury

BackgroundThe World Health Organization (WHO) and the International Labour Organization (ILO) are developing joint estimates of the work-related burden of disease and injury (WHO/ILO Joint Estimates), with contributions from a large network of individual experts. Evidence from mechanistic and human data suggests that occupational exposure to noise may cause cardiovascular disease. In this paper, we present a systematic review and meta-analysis of the prevalence of occupational exposure to noise for estimating (if feasible) the number of deaths and disability-adjusted life years from cardiovascular disease that are attributable to exposure to this risk factor, for the development of the WHO/ILO Joint Estimates. ObjectivesWe aimed to systematically review and meta-analyse estimates of the prevalence of occupational exposure to noise. Data sourcesWe searched electronic academic databases for potentially relevant records from published and unpublished studies, including Ovid Medline, PubMed, EMBASE, and CISDOC. We also searched electronic grey literature databases, Internet search engines, and organizational websites; hand-searched reference list of previous systematic reviews and included study records; and consulted additional experts. Study eligibility and criteriaWe included working-age (≥15 years) workers in the formal and informal economies in any WHO Member and/or ILO member State, but excluded children (<15 years) and unpaid domestic workers. We included all study types with an estimate of the prevalence of occupational exposure to noise, categorized into two levels: no (low) occupational exposure to noise (<85dBA) and any (high) occupational exposure to noise (≥85dBA). Study appraisal and synthesis methodsAt least two review authors independently screened titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. We combined prevalence estimates using random-effect meta-analysis. Two or more review authors assessed the risk of bias and the quality of evidence, using the RoB-SPEO tool and QoE-SPEO approach developed specifically for the WHO/ILO Joint Estimates. ResultsSixty-five studies (56 cross-sectional studies and nine cohort studies) met the inclusion criteria, comprising 157,370 participants (15,369 females) across 28 countries and all six WHO regions (Africa, Americas, Eastern Mediterranean, Europe, South-East Asia, and Western Pacific). For the main analyses, we prioritized the four included studies that surveyed national probability samples of general populations of workers over the 58 studies of workers in industrial sectors and/or occupations with relatively high occupational exposure to noise. The exposure was generally assessed with dosimetry, sound level meter, or official or company records; in the population-based studies, it was assessed with validated questions. Estimates of the prevalence of occupational exposure to noise are presented for all 65 included studies, by country, sex, 5-year age group, industrial sector, and occupation where feasible. The pooled prevalence of any (high) occupational exposure to noise (≥85dBA) among the general population of workers was 0.17 (95% confidence interval 0.16 to 0.19, 4 studies, 108,256 participants, 38 countries, two WHO regions, I2 98%, low quality of evidence). Subgroup analyses showed that pooled prevalence differed substantially by WHO region, sex, industrial sector, and occupation. ConclusionsOur systematic review and meta-analysis found that occupational exposure to noise is prevalent among general populations of workers. The current body of evidence is, however, of low quality, due to serious concerns for risk of bias and indirectness. Producing estimates of occupational exposure to noise nevertheless appears evidence-based, and the pooled effect estimates presented in this systematic review are suitable as input data for the WHO/ILO Joint Estimates (if feasible).Protocol identifier: 10.1016/j.envint.2018.09.040PROSPERO registration number: CRD42018092272

Estimating plasma half-lives of dioxin like and non-dioxin like polychlorinated biphenyls after occupational exposure in the German HELPcB cohort.

Polychlorinated biphenyls (PCBs) are carcinogenic persistent organic pollutants that have been used as mixtures in transformers, electrical capacitors or hydraulic oils in underground mining until their ban in the late 1980s in Germany. The widespread use of PCBs has led to an age-dependent body burden in the general population. In order to determine the human half-lives of different PCB-congeners, we have used data collected between 2010 and 2017 from the prospective investigation of the German HELPcB-cohort with high initial occupational exposure to PCBs from a transformer recycling company. PCBs were quantified in plasma of the study participants in six cross-sectional investigations using gas-chromatography coupled to mass-spectrometry. Applying logistic regression on the individual plasma levels after statistical elimination of outliers, the elimination half-lives of 18 PCB-congeners were determined. Further stratifications were performed using adjustment for blood lipids, calculation of the total amount of PCB in the body and by using a statistical model taking into account the individual age-dependent background burden. The calculated plasma half-lives ranged from 0.8 years for PCB 52 until a maximum of 28.9 years for PCB 189, depending on the model applied. E.g. the total body amount related half-live for PCB 28 is 2.41 years, for PCB 74 it is 12.81 years, for PCB 118 it is 6.65 years and for PCB 153=10.75 years. The model with adjustment for age dependent background burden led to shorter half-lives. The analysis revealed structure-related differences in the kinetics for the PCB-congeners examined. Congeners with a chlorine substitution in 2,4,(5)- and 4'-position showed longer half-lives than other isomers with one (or two) free 4-positions. Due to the high number of included cases and repeated measurements, our results provide valid half-live data for a large number of PCB congeners. Using these data, a rough estimation of former occupational exposures from current PCB-levels seems feasible.

Estimation of Occupational Exposure during Ceramic Manufacturing

Introduction: The present study investigated the relatively high concentrations of natural radionuclides in raw material that used in ceramic manufacturing, and estimated the occupational exposure due to these activity concentrations. Material and Methods: A high-purity Germanium detector was used to determine naturally occurring radionuclides in raw materials that used in ceramic manufacturing. Activity concentrations of these materials lead to potential radiological hazards due to gamma and alpha radiation. These hazards were evaluated in the present study. Results: Maximum activity concentrations was5844, 1065 and 41 Bq/kg for 226Ra, 232Th and 235U in powdered quartz; however, maximum activity concentration for 40K was 1868 Bq/kg in colors. These activities were observed to be exceeding the exemption limit. Pancreasreceived the lowest dose (i.e., 0.02 mSv/y), while skin received the highest dose (i.e., 0.044mSv/y). Internal hazard index (Hin) was reported as 53.74, which exceed the recommended value (Hin≤1). Alpha index was 42.4 which led to over exposure. Representative level index and excess lifetime cancer risk were 0.00062 and 0.641 respectively. The total annual external dose was 2.62 m Gy/y which led to 1.83 mSv/y effective dose. Radiological hazard due to radon inhalation was 1.53E-06 mSv/y. Conclusion: Due to the high activity concentrations of raw materials (especially zirconium compounds) and consequently the associated high dose, specific regulations must be applied in the ceramic industry in Egypt.

Estimation of Occupational Exposure to Asbestos in Italy by the Linkage of Mesothelioma Registry (ReNaM) and National Insurance Archives. Methodology and Results

The identification and monitoring of occupational cancer is an important aspect of occupational health protection. The Italian law on the protection of workers (D. Leg. 81/2008) includes different cancer monitoring systems for high and low etiologic fraction tumors. Record linkage between cancer registries and administrative data is a convenient procedure for occupational cancer monitoring. We aim to: (i) Create a list of industries with asbestos exposure and (ii) identify cancer cases who worked in these industries. The Italian National Mesothelioma Registry (ReNaM) includes information on occupational asbestos exposure of malignant mesothelioma (MM) cases. We developed using data from seven Italian regions a methodology for listing the industries with potential exposure to asbestos linking ReNaM to Italian National Social Security Institute (INPS) data. The methodology is iterative and adjusts for imprecision and inaccuracy in reporting firm names at interview. The list of asbestos exposing firms was applied to the list of cancer cases (all types associated or possibly associated with asbestos according to International Agency for Research on Cancer (IARC) monograph 100C) in two Italian regions for the indication of possible asbestos exposure. Eighteen percent of the cancer cases showed at least one work period in firms potentially exposing to asbestos, 48% of which in regions different from where the cases lived at diagnosis. The methodology offers support for the preliminary screening of asbestos exposing firms in the occupational history of cancer cases.

Estimation of inhalation exposure to metals among welders of a steel company using MEASE model: as a screening tool for estimates of occupational exposure

Introduction: Metals estimation assessment of substance exposure (MEASE) is tier1 tool to estimation exposures. The aim of present study was estimation of exposure to welding fumes using MEASE model and comparison of the results with NIOSH7300. Materials and methods: The metals including Cu, Fe, Ca, Al, Mg, Mn, K and Na in the MIG, MAG and SMAW welding were measured by NIOSH7300. Estimation of the metals' values was performed by MEASE (version1.02.01). Data analysis were done by SPSS21 using Student's t-test, One-WayANOVA and Spearman's correlation. Results and discussion: There was agreement between measured and estimated values in different metal fumes and welding processes (r = 0.131 to 0.933). A significant strong correlation was found between measured and estimated levels for Mg(r = 0.933; P = 0.001), Ca(r = 0.896; P = 0.001), K(r = 0.805; P = 0.001), Na(r = 0.716; P = 0.001), and Al(r = 0.756; P = 0.032). There was a significant strong correlation between measured and estimated values for SMAW(r = 0.708; P = 0.003) and MIG(r = 0.635; P = 0.036). The results showed that most of the estimated values were below the measured values (P < 0.05), except for Ca in MIG welding. The authors observed that the MEASE model cannot be wholly successfully applied for inhalation exposure assessment in occupational surveys.

Estimation of inhalation exposure to metals among welders of a steel company using MEASE model as a screening tool for estimates of occupational exposure

Estimation of inhalation exposure to metals among welders of a steel company using MEASE model as a screening tool for estimates of occupational exposure

Validity of Retrospective Occupational Exposure Estimates of Lead and Manganese in a Case-Control Study

TPS 792: Occupational health 2, Exhibition Hall, Ground floor, August 27, 2019, 3:00 PM - 4:30 PM Background: The validity of surrogate measures of retrospective occupational exposure in population-based epidemiological studies has rarely been evaluated. Using toenail samples as indicators of biologic exposure, we assessed whether work tasks and expert assessments of occupational metal exposure obtained from personal interviews were associated with lead and manganese concentrations. Methods: We selected 609 controls from a case-control study of bladder cancer in New England who had held a job for ≥1 year 8-24 months prior to toenail collection. We evaluated associations between toenail metal concentrations and five tasks extracted from occupational questionnaires (grinding, painting, soldering, welding, working near engines) using linear regression models. For 139 subjects, we also evaluated associations between the toenail concentrations and exposure estimates from three experts. Results: We observed a 1.9-fold increase (95% confidence interval (CI) 1.4-2.5) in toenail lead concentrations with painting and 1.4-fold increase (95%CI 1.1-1.7) in manganese concentrations with working around engines and handling fuel. We observed significant trends with increasing frequency of both activities. For lead, significant trends were observed with the ratings from all three experts. Their average ratings showed the strongest association, with subjects rated as possibly or probably exposed to lead having concentrations that were 2.0 and 2.5 times higher, respectively, than in unexposed subjects (Ptrend<0.001). Expert estimates were only weakly associated with manganese toenail concentrations. Conclusions: Our findings support the validity of surrogate measures to assess occupational exposure in epidemiologic studies. The stronger associations with task frequency and expert assessments support using refined exposure characterization whenever possible.

Estimation of Source-Specific Occupational Benzene Exposure in a Population-Based Case-Control Study of Non-Hodgkin Lymphoma.

Occupational exposures in population-based case-control studies are increasingly being assessed using decision rules that link participants' responses to occupational questionnaires to exposure estimates. We used a hierarchical process that incorporated decision rules and job-by-job expert review to assign occupational benzene exposure estimates in a US population-based case-control study of non-Hodgkin lymphoma. We conducted a literature review to identify scenarios in which occupational benzene exposure has occurred, which we grouped into 12 categories of benzene exposure sources. For each source category, we then developed decision rules for assessing probability (ordinal scale based on the likelihood of exposure > 0.02 ppm), frequency (proportion of work time exposed), and intensity of exposure (in ppm). The rules used the participants' occupational history responses and, for a subset of jobs, responses to job- and industry-specific modules. For probability and frequency, we used a hierarchical assignment procedure that prioritized subject-specific module information when available. Next, we derived job-group medians from the module responses to assign estimates to jobs with only occupational history responses. Last, we used job-by-job expert review to assign estimates when job-group medians were not available or when the decision rules identified possible heterogeneous or rare exposure scenarios. For intensity, we developed separate estimates for each benzene source category that were based on published measurement data whenever possible. Frequency and intensity annual source-specific estimates were assigned only for those jobs assigned ≥75% probability of exposure. Annual source-specific concentrations (intensity × frequency) were summed to obtain a total annual benzene concentration for each job. Of the 8827 jobs reported by participants, 8% required expert review for one or more source categories. Overall, 287 (3.3%) jobs were assigned ≥75% probability of exposure from any benzene source category. The source categories most commonly assigned ≥75% probability of exposure were gasoline and degreasing. The median total annual benzene concentration among jobs assigned ≥75% probability was 0.11 ppm (interquartile range: 0.06-0.55). The highest source-specific median annual concentrations were observed for ink and printing (2.3 and 1.2 ppm, respectively). The applied framework captures some subject-specific variability in work tasks, provides transparency to the exposure decision process, and facilitates future sensitivity analyses. The developed decision rules can be used as a starting point by other researchers to assess occupational benzene exposure in future population-based studies.

Validity of retrospective occupational exposure estimates of lead and manganese in a case–control study

ObjectivesThe validity of surrogate measures of retrospective occupational exposure in population-based epidemiological studies has rarely been evaluated. Using toenail samples as bioindicators of exposure, we assessed whether work tasks and...

Interview

Valentina Hartwig Doctor Valentina Hartwig from the National Research Council in Italy, talks to Electronics Letters about the paper ‘New device for the assessment of occupational exposure to time-varying magnetic field due to movement in Magnetic Resonance environments’, page 579. I have been intrigued by the interactions between electromagnetic fields and biological tissues for many years, and my PhD was on this topic. This is an interesting research topic and what I love most about this subject is its multidisciplinary approach. Specifically, exposure to electromagnetic fields in Magnetic Resonance (MR) environments is currently a hot topic. MR is widely used for clinical applications and, at the Institute of Clinical Physiology where I work, is also used as a powerful research tool for cardiovascular diseases. In the past, we studied patient exposure to electromagnetic fields in MR and, at present, we focus on occupational exposure in MR environments, an exciting challenge. According to the most recent international regulations and guidelines, training of MR professionals is necessary to avoid the risks of high electromagnetic field exposure. There is still the lack of a practical method for exposure assessment, particularly when considering risks for MR staff moving across the permanent static magnetic field straying from the scanner. For these reasons, we had the idea to design a device for assessing personal exposure to the magnetic fields, to use not only as a “personal dosimeter”, but also for educational purposes. Our target was using this simple instrument to identify preventive measures and to provide staff with some recommendations on how to move around the MR room during daily clinical practice. There are at present some commercial MR dosimeters, but these devices have been designed for exposure assessment purposes at only one position on the workers body and are not suitable for newer research MR scanners with very high values of static magnetic fields. Our device is designed for research purposes, offering the possibility to measure the magnetic field at different positions on the body simultaneously, which is important in epidemiological studies. Moreover, it may be used in all clinical MR environments and in experimental MR scanners with a static magnetic field value up to 7 T. In its development is encompassed our mission of “technology transfer”, from basic research to industry and, it is the result of successful cooperation between research institutions and industrial partners. An MR site is an environment which poses exciting challenges, especially for designing an electronic device for use within it, as even the simplest electronic circuit may not function correctly. Our challenge was to design a wearable device that is not affected by the fields present and permits measurement and recording of exposure parameters; all without disturbing the work of the operator wearing it. This was possible thanks to the thorough study of the chosen material and components electromagnetic compatibilities. We performed many tests both in the laboratory and in real MR environments and achieved our goal thanks to the hard work of a multidisciplinary team. In the short term, we expect that the device described in our paper will be useful in better understanding occupational exposure to magnetic fields in MR sites. In the longer term, after optimisation of the present prototype, the device may be commercialised and used for workers training and/or epidemiological studies. Future developments of this work will regard the optimisation of the device in terms of size, storage capacity, and the implementation of a wireless-real-time connection to a host device. We are also working on a computational tool for the estimation of occupational exposure to time-varying electromagnetic fields due to the movement inside the MR environment. In recent years, the scientific community's interest in MR environment safety has been growing exponentially, especially after the publication, in 2013, of a specific Directive of the EU, followed in 2014 by updated ICNIRP guidelines. To date, there are many scientific works which deal with MR safety, hence we have a good understanding of magnetic field exposure levels by workers. What is still missing today are epidemiological studies conducted using consolidated assessment methodologies to collect exposure data at a personal level by means of simple everyday equipment. I think that over the next ten years research on this topic will grow both from the point of view of studies on the biological effects of electromagnetic fields typical of the MR environment, and from that of devices for measuring exposure to this type of physical agents. Our work will, therefore, contribute to this latter research activity.

Case-control investigation of occupational lead exposure and kidney cancer

ObjectivesLead is a suspected carcinogen that has been inconsistently associated with kidney cancer. To clarify this relationship, we conducted an analysis of occupational lead exposure within a population-based study of...