Occupational exposure to chrysotile in an asbestos cement factory in Kyrgyzstan.

OBJECTIVES: An increasing number of countries are banning the production and use of asbestos, in compliance with the ratification of the C162 Asbestos Convention and the Basel Convention, and in response to the call for its elimination in the ILO resolution and WHO reports on the health risks associated with asbestos. Nevertheless, several countries, including Kyrgyzstan, are still miners and/or manufacturers of asbestos. The main objective of the study is to assess the occupational exposure to chrysotile of workers engaged in a production facility of asbestos-cement products in Kyrgyzstan. METHODS: Monitored workers (n = 16, for a total of n = 18 samples) were divided into 3 "Similar Exposure Groups" (SEGs; SEG-1: asbestos loading; SEG-2; asbestos-cement mixing; SEG-3: cutting of asbestos-cement sheets) according to EN 689 standard. Samples were collected through personal sampling and subsequently examined by means of scanning electron microscope equipped with an energy-dispersive spectrometer for the compositional analysis of each fibre. The numerical concentration of airborne asbestos fibres was henceforward determined by dividing the number of fibres and the volume of sampled air (expressed in the number of fibres per millilitre of air: ff/ml). RESULTS: Investigated workers resulted to be exposed to chrysotile fibres. Results (GM ± GSD) outlined extremely high exposure levels for SEG-1 (2.2 ± 2.1 ff/ml) and SEG-3 (4.7 ± 1.6 ff/ml) workers and lower-but still relevant-exposure values for SEG-2 (0.91 ± 2.6 ff/ml) workers. CONCLUSIONS: The results obtained in this case study can help to document potentially critical situations of occupational exposure to asbestos that can still occur nowadays in low and middle-income countries where asbestos is still mined and processed.

Exposure to airborne particulate matter in working from office and working from home employees.

The main aim of this study is to quantitatively evaluate the differences, in terms of exposure to PM (particulate matter), between WFO (working-from-office) and WFH (working-from-home) conditions. Two measurement surveys were performed: a long-term and a short-term campaign, focused on the monitoring of personal exposure to size-fractionated PM in these different working conditions. Results of the long-term campaign show that the WFH subject is exposed to higher (up to 4 times) PM concentration, compared to the WFO subject. Specific activities performed by the subjects impacted their exposure concentrations, even if the most relevant contribution to total exposure was made by desk work. Results of the short-term campaign indicate that the subjects can be divided into two groups: subjects most exposed during the WFH mode (HE_H - Higher_Exposure_Home) and subjects most exposed during the WFO mode (HE_O - Higher_Exposure_Office). HE_H group is exposed to levels of pollutants up to 4 times higher in the domestic than in the office environment, during the moment of desk work. The HE_O group is exposed to higher (double) concentration levels during desk work during the WFO day. Considering the possible growing trend towards remote work it is important to evaluate these "new domestic offices" comprehensively.

Exposure Assessment and Monitoring of Antiblastic Drugs Preparation in Health Care Settings: A Systematic Review.

Several antiblastic drugs (ADs) are classified as carcinogenic, mutagenic, and/or toxic for reproduction. Despite established guidelines and safe handling technologies, ADs contamination of the work environments could occur in healthcare settings, leading to potential exposure of healthcare staff. This systematic review aims to investigate the main techniques and practices for assessing ADs occupational exposure in healthcare settings. The reviewed studies unveil that workplace contamination by ADs appears to be a still-topical problem in healthcare settings. These issues are linked to difficulties in guaranteeing: (i) the adherence to standardized protocols when dealing with ADs, (ii) the effective use of personal protective equipment by operators involved in the administration or management of ADs, (iii) a comprehensive training of the healthcare personnel, and (iv) a thorough health surveillance of exposed workers. A "multi-parametric" approach emerges as a desirable strategy for exposure assessment. In parallel, exposure assessment should coincide with the introduction of novel technologies aimed at minimizing exposure (i.e., risk management). Assessment must consider various departments and health operators susceptible to ADs contamination, with a focus extended beyond worst-case scenarios, also considering activities like surface cleaning and logistical tasks related to ADs management. A comprehensive approach in ADs risk assessment enables the evaluation of distinct substance behaviors and subsequent exposure routes, affording a more holistic understanding of potential risks.

An In-Field Assessment of the P.ALP Device in Four Different Real Working Conditions: A Performance Evaluation in Particulate Matter Monitoring.

This study aimed to assess the performance, in terms of precision and accuracy, of a prototype (called "P.ALP"-Ph.D. Air Quality Low-cost Project) developed for monitoring PM2.5 concentration levels. Four prototypes were co-located with reference instrumentation in four different microenvironments simulating real-world and working conditions, namely (i) office, (ii) home, (iii) outdoor, and (iv) occupational environments. The devices were evaluated for a total of 20 monitoring days (approximately 168 h) under a wide range of PM2.5 concentrations. The performances of the prototypes (based on the light-scattering working principle) were tested through different statistical methods. After the data acquisition and data cleaning processes, a linear regression analysis was performed to assess the precision (by comparing all possible pairs of devices) and the accuracy (by comparing the prototypes against the reference instrumentation) of the P.ALP. Moreover, the United States Environmental Protection Agency (US EPA) criteria were applied to assess the possible usage of this instrumentation, and to evaluate the eventual error trends of the P.ALP in the data storage process, Bland-Altman plots were also adopted. The outcomes of this study underlined that the P.ALP performed differently depending on the microenvironment in which it was tested and, consequently, on the PM2.5 concentrations. The device can monitor PM2.5 variations with acceptable results, but the performance cannot be considered satisfactory at extremely low and remarkably high PM2.5 concentrations. Thanks to modular components and open-source software, the tested device has the potential to be customized and adapted to better fit specific study design needs, but it must be implemented with ad hoc calibration factors depending on the application before being used in field.

Understanding the limitations and application of occupational exposure models in a REACH context.

Exposure modeling plays a significant role for regulatory organizations, companies, and professionals involved in assessing and managing occupational health risks in workplaces. One context in which occupational exposure models are particularly relevant is the REACH Regulation in the European Union (Regulation (EC) No 1907/2006). This commentary describes the models for the occupational inhalation exposure assessment of chemicals within the REACH framework, their theoretical background, applications, and limitations, as well as the latest developments and priorities for model improvement. Summing up the debate, despite its relevance and importance in the context of REACH not being in question, occupational exposure modeling needs to be improved in many respects. There is a need to reach a wide consensus on several key issues (e.g., the theoretical background and the reliability of modeling tools), to consolidate and monitor model performance and regulatory acceptance, and to align practices and policies regarding exposure modeling.

On the Determination of Cr(VI) in Cr(III)-Rich Particulates: From the Failure of Official Methods to the Development of an Alternative Protocol.

The goals of this work are the evaluation of the performances of official methods in the challenging determination of Cr(VI) in Cr(III)-rich particulate matter, and the development of a novel and robust analytical protocol for this issue. A liquid chromatography inductively coupled plasma mass spectrometry apparatus (LC-ICP-MS), together with an isotope-enriched spike addition technique, was used to allow the study of Cr(III)/Cr(VI) interconversions during the extraction step. An original separation strategy based on Cr(OH)3 head-column stacking was developed to tolerate high concentrations of Cr(III) (up to 10 mg/kg, with a Cr(VI) limit of detection of 0.51 µg/kg) without the need of any sample pretreatment. After observing, the official extraction protocols always yield false positive values in the challenging situation of particulate matter of leather industries (where huge amounts of Cr(III) are present), a new extraction strategy was developed. The novel procedure involves a 48-h extraction at room temperature using a pH-8 phosphate buffer, which demonstrated that no Cr(III)/Cr(VI) interconversions occur during this phase. To get rid of any possible interference caused by co-extracted substances, the measurement of the redox potential, together with the addition of a Fe(II)/Fe(III) redox buffer was performed to fix chromium speciation during the overall analytical protocol.

Exposure modelling in Europe: how to pave the road for the future as part of the European Exposure Science Strategy 2020-2030.

Exposure models are essential in almost all relevant contexts for exposure science. To address the numerous challenges and gaps that exist, exposure modelling is one of the priority areas of the European Exposure Science Strategy developed by the European Chapter of the International Society of Exposure Science (ISES Europe). A strategy was developed for the priority area of exposure modelling in Europe with four strategic objectives. These objectives are (1) improvement of models and tools, (2) development of new methodologies and support for understudied fields, (3) improvement of model use and (4) regulatory needs for modelling. In a bottom-up approach, exposure modellers from different European countries and institutions who are active in the fields of occupational, population and environmental exposure science pooled their expertise under the umbrella of the ISES Europe Working Group on exposure models. This working group assessed the state-of-the-art of exposure modelling in Europe by developing an inventory of exposure models used in Europe and reviewing the existing literature on pitfalls for exposure modelling, in order to identify crucial modelling-related strategy elements. Decisive actions were defined for ISES Europe stakeholders, including collecting available models and accompanying information in a living document curated and published by ISES Europe, as well as a long-term goal of developing a best-practices handbook. Alongside these actions, recommendations were developed and addressed to stakeholders outside of ISES Europe. Four strategic objectives were identified with an associated action plan and roadmap for the implementation of the European Exposure Science Strategy for exposure modelling. This strategic plan will foster a common understanding of modelling-related methodology, terminology and future research in Europe, and have a broader impact on strategic considerations globally.

Evolution and Applications of Recent Sensing Technology for Occupational Risk Assessment: A Rapid Review of the Literature.

Over the last decade, technological advancements have been made available and applied in a wide range of applications in several work fields, ranging from personal to industrial enforcements. One of the emerging issues concerns occupational safety and health in the Fourth Industrial Revolution and, in more detail, it deals with how industrial hygienists could improve the risk-assessment process. A possible way to achieve these aims is the adoption of new exposure-monitoring tools. In this study, a systematic review of the up-to-date scientific literature has been performed to identify and discuss the most-used sensors that could be useful for occupational risk assessment, with the intent of highlighting their pros and cons. A total of 40 papers have been included in this manuscript. The results show that sensors able to investigate airborne pollutants (i.e., gaseous pollutants and particulate matter), environmental conditions, physical agents, and workers' postures could be usefully adopted in the risk-assessment process, since they could report significant data without significantly interfering with the job activities of the investigated subjects. To date, there are only few "next-generation" monitors and sensors (NGMSs) that could be effectively used on the workplace to preserve human health. Due to this fact, the development and the validation of new NGMSs will be crucial in the upcoming years, to adopt these technologies in occupational-risk assessment.

Dynamic Olfactometry and Oil Refinery Odour Samples: Application of a New Method for Occupational Risk Assessment.

Refineries are characterized by relevant odour impacts, and the control and monitoring of this pollutant have become increasingly important. Dynamic olfactometry, a sensorial analysis that involves human examiners, is currently the most common technique to obtain odour quantification. However, due to the potential presence of hazardous pollutants, the conduction of occupational risk assessment is necessary to guarantee examiners' safety. Nevertheless, the occupational risk for olfactometric examiners, specifically correlated with oil refineries emissions, has not been investigated yet. Therefore, this paper applies a new methodology of risk assessment for workers involved in dynamic olfactometry, focusing on odorous refineries emissions. The chemical characterization of refinery emissions was obtained by TD-GC-MS, analysing odorous samples collected at different refinery odour sources. A database of chemical pollutants emitted from a refinery plant was built up, and the minimum dilution values to be adopted during the analysis of refinery odorous samples was calculated. In particular, this evaluation highlighted that, in this scenario, a non-negligible carcinogenic risk may exist for panellists exposed to refineries' samples, and the carcinogenic risk is sometimes higher than what is acceptable. Therefore, a minimum dilution value between 1.01 and 5, according to the specific sample, must be set to guarantee the examiners' safety.

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.

Development of a Crosswalk to Translate Italian Occupation Codes to ISCO-68 Codes.

In occupational epidemiology, job coding is an important-but time-consuming-step in assigning exposure. We implemented a tool (i.e. a crosswalk) to translate occupation codes from the Italian (ISTAT-CIP-91, n = 6319 five-digit job codes) to the International Standard Classification of Occupations (ISCO-68, n = 1881 five-digit job codes). The former is currently used in Italy for various purposes (e.g. in the National Mesothelioma Registry). The latter has been used in several studies on occupational cancers because it facilitates communication of results to the scientific community and, most importantly, because some job exposure matrices (JEMs) are based on international codes. Three authors created a table containing the crosswalk structure, providing an interpretation for each of the ISTAT-CIP-91 codes job descriptions and then manually recoding them according to ISCO-68. Two other authors independently revised it. The performance of the final version was assessed by comparison with results obtained by manual ISCO-68 coding performed in two previous case-control studies on asbestos and mesothelioma. More specifically, the automatically obtained ISCO-68 codes were merged with a JEM (DOM-JEM). The resulting individual asbestos exposure estimates (ever versus never exposed) were compared to those originally obtained (using the same DOM-JEM) from manual translation of ISTAT-CIP-91 to ISCO-68 (considered as the 'gold standard'). In the first study, among 159 peritoneal mesothelioma cases (400 job codes), Cohen's kappa was 0.91, sensitivity 0.95, and specificity 0.96. In the second study, among 716 pleural mesothelioma cases and controls (4400 job codes) kappa was 0.86, sensitivity 0.94, and specificity 0.91. Performance was better among in women. For men, performance was lower among cases than among controls (kappa 0.70, sensitivity 0.95, specificity 0.72 versus kappa 0.87, sensitivity 0.97, and specificity 0.92). In conclusion, the proposed tool allowed a rapid translation of thousands of job codes with good to excellent accuracy. The table containing ISTAT-CIP-91 codes and job descriptions and the corresponding ISCO-68 codes and job descriptions is made publicly available and can be freely used for epidemiological analyses in Italy and international collaborations.

Response Letter to Koivisto et al. 'Evaluating the Theoretical Background of STOFFENMANAGER® and the Advanced REACH Tool'.

In this article, we have responded to the key statements in the article by Koivisto et al. (2022) that were incorrect and considered to be a biased critique on a subset of the exposure models used in Europe (i.e. ART and Stoffenmanager®) used for regulatory exposure assessment. We welcome scientific discussions on exposure modelling (as was done during the ISES Europe workshop) and criticism based on scientific evidence to contribute to the advancement of occupational exposure estimation tools. The tiered approach to risk assessment allows various exposure assessment models from screening tools (control/hazard banding) through to higher-tiered approaches. There is a place for every type of model, but we do need to recognize the cost and data requirements of highly bespoke assessments. That is why model developers have taken pragmatic approaches to develop tools for exposure assessments based on imperfect data. We encourage Koivisto et al. to focus on further scientifically robust work to develop mass-balance models and by independent external validations studies, compare these models with alternative model tools such as ART and Stoffenmanager®.

Theoretical Background of Occupational-Exposure Models-Report of an Expert Workshop of the ISES Europe Working Group "Exposure Models".

On 20 October 2020, the Working Group "Exposure Models" of the Europe Regional Chapter of the International Society of Exposure Science (ISES Europe) organised an online workshop to discuss the theoretical background of models for the assessment of occupational exposure to chemicals. In this report, participants of the workshop with an active role before and during the workshop summarise the most relevant discussion points and conclusions of this well-attended workshop. ISES Europe has identified exposure modelling as one priority area for the strategic development of exposure science in Europe in the coming years. This specific workshop aimed to discuss the main challenges in developing, validating, and using occupational-exposure models for regulatory purposes. The theoretical background, application domain, and limitations of different modelling approaches were presented and discussed, focusing on empirical "modifying-factor" or "mass-balance-based" approaches. During the discussions, these approaches were compared and analysed. Possibilities to address the discussed challenges could be a validation study involving alternative modelling approaches. The wider discussion touched upon the close relationship between modelling and monitoring and the need for better linkage of the methods and the need for common monitoring databases that include data on model parameters.

Occupational Exposure to Halogenated Anaesthetic Gases in Hospitals: A Systematic Review of Methods and Techniques to Assess Air Concentration Levels.

Objective During the induction of gaseous anaesthesia, waste anaesthetic gases (WAGs) can be released into workplace air. Occupational exposure to high levels of halogenated WAGs may lead to adverse health effects; hence, it is important to measure WAGs concentration levels to perform risk assessment and for health protection purposes. Methods A systematic review of the scientific literature was conducted on two different scientific databases (Scopus and PubMed). A total of 101 studies, focused on sevoflurane, desflurane and isoflurane exposures in hospitals, were included in this review. Key information was extracted to provide (1) a description of the study designs (e.g., monitoring methods, investigated occupational settings, anaesthetic gases in use); (2) an evaluation of time trends in the measured concentrations of considered WAGs; (3) a critical evaluation of the sampling strategies, monitoring methods and instruments used. Results Environmental monitoring was prevalent (68%) and mainly used for occupational exposure assessment during adult anaesthesia (84% of cases). Real-time techniques such as photoacoustic spectroscopy and infrared spectrophotometry were used in 58% of the studies, while off-line approaches such as active or passive sampling followed by GC-MS analysis were used less frequently (39%). Conclusions The combination of different instrumental techniques allowing the collection of data with different time resolutions was quite scarce (3%) despite the fact that this would give the opportunity to obtain reliable data for testing the compliance with 8 h occupational exposure limit values and at the same time to evaluate short-term exposures.

Features and Practicability of the Next-Generation Sensors and Monitors for Exposure Assessment to Airborne Pollutants: A Systematic Review.

In the last years, the issue of exposure assessment of airborne pollutants has been on the rise, both in the environmental and occupational fields. Increasingly severe national and international air quality standards, indoor air guidance values, and exposure limit values have been developed to protect the health of the general population and workers; this issue required a significant and continuous improvement in monitoring technologies to allow the execution of proper exposure assessment studies. One of the most interesting aspects in this field is the development of the "next-generation" of airborne pollutants monitors and sensors (NGMS). The principal aim of this review is to analyze and characterize the state of the art and of NGMS and their practical applications in exposure assessment studies. A systematic review of the literature was performed analyzing outcomes from three different databases (Scopus, PubMed, Isi Web of Knowledge); a total of 67 scientific papers were analyzed. The reviewing process was conducting systematically with the aim to extrapolate information about the specifications, technologies, and applicability of NGMSs in both environmental and occupational exposure assessment. The principal results of this review show that the use of NGMSs is becoming increasingly common in the scientific community for both environmental and occupational exposure assessment. The available studies outlined that NGMSs cannot be used as reference instrumentation in air monitoring for regulatory purposes, but at the same time, they can be easily adapted to more specific applications, improving exposure assessment studies in terms of spatiotemporal resolution, wearability, and adaptability to different types of projects and applications. Nevertheless, improvements needed to further enhance NGMSs performances and allow their wider use in the field of exposure assessment are also discussed.

Toxicological assessment method for evaluating the occupational risk of dynamic olfactometry assessors.

The paper aims to propose a new method to evaluate the occupational exposure risk for examiners involved in dynamic olfactometry. Indeed, examiners are possibly exposed to hazardous pollutants potentially present in odorous samples. A standardized method to evaluate the examiners' occupational safety is not yet available and the existing models present some critical aspect if applied to real odorous samples (no uniform reference concentrations applied and presence of compounds for which no toxicity threshold is available). A deepening of assessment procedure to evaluate the occupation exposure risk for olfactometric assessors is necessary. This paper proposes a standardized approach for risk assessment in dynamic olfactometry. The proposed approach allows the quantification synthetic and conservative risk indices. In this model, the use of the hazard index for the odorous mixture was proposed to assess the non-carcinogenic risk; the calculation of the inhalation risk was applied to estimate the carcinogenic risk. Different databases can be used to retrieve proper occupational exposure limits, according to the proposed hierarchical basis. These implementations allow obtaining the complete characterization of real samples which can be used to calculate the minimum dilution factor for protecting the panellists' health.

Estimation of the Inhaled Dose of Pollutants in Different Micro-Environments: A Systematic Review of the Literature.

Recently, the need to assess personal exposure in different micro-environments has been highlighted. Further, estimating the inhaled dose of pollutants is considerably one of the most interesting parameters to be explored to complete the fundamental information obtained through exposure assessment, especially if associated with a dose-response approach. To analyze the main results obtained from the studies related to the estimation of the inhaled dose of pollutants in different micro-environments (environments in which an individual spends a part of his day), and to identify the influence of different parameters on it, a systematic review of the literature was performed. The principal outcomes from the considered studies outlined that (i) exposure concentration and residence time are among the most important parameters to be evaluated in the estimation of the inhaled dose, especially in transport environments. Further, (ii) the pulmonary ventilation rate can be of particular interest during active commuting because of its increase, which increases the inhalation of pollutants. From a methodological point of view, the advent of increasingly miniaturized, portable and low-cost technologies could favor these kinds of studies, both for the measurement of atmospheric pollutants and the real-time evaluation of physiological parameters used for estimation of the inhaled dose. The main results of this review also show some knowledge gaps. In particular, numerous studies have been conducted for the evaluation (in terms of personal exposure and estimation of the inhaled dose) of different PM fractions: other airborne pollutants, although harmful to human health, are less represented in studies of this type: for this reason, future studies should be conducted, also considering other air pollutants, not neglecting the assessment of exposure to PM. Moreover, many studies have been conducted indoors, where the population spends most of their daily time. However, it has been highlighted how particular environments, even if characterized by a shorter residence time, can contribute significantly to the dose of inhaled pollutants. These environments are, therefore, of particular importance and should be better evaluated in future studies, as well as occupational environments, where the work results in a high pulmonary ventilation rate. The attention of future studies should also be focused on these categories of subjects and occupational studies.

Exposure and Management of the Health Risk for the Use of Formaldehyde and Xylene in a Large Pathology Laboratory.

BACKGROUND: Formaldehyde and xylene are two hazardous chemicals widely used in pathology laboratories all over the world. The aim of this work was to survey a large volume pathology lab, measuring exposure of workers and residents to formaldehyde and xylene, and verify the efficacy of the undertaken preventive actions and the accomplishment with occupational limit values. METHODS: Environmental, personal, and biological monitoring of exposure to formaldehyde and xylene in different lab rooms and in 29 lab attendants was repeated yearly from 2017 to 2020. Continuous monitoring of airborne formaldehyde was performed to evaluate the pattern of airborne concentrations while specific tasks were performed. Several risk management and mitigation measures, including setting a new grossing room, reducing the number of samples to be soaked in formaldehyde, and improving the lab practices and equipment, such as the use of chemical hoods, were undertaken after each monitoring campaign, based on the results obtained from the exposure monitoring. RESULTS: Significant exposures to formaldehyde in pathologists and residents, especially during the grossing of samples, were observed in the first 2 years, with exposure exceeding the occupational exposure limit value; the following surveys showed that the risk management and mitigation measures were effective in reducing airborne concentrations and personal exposure. Xylene, assessed with both environmental and biological monitoring, was always well below the occupational exposure limit value and biological limit values, respectively. CONCLUSION: Critical exposure to air formaldehyde in attendants of a pathology laboratory could be reduced with the re-organization of lab spaces, new and improved work procedures, and awareness and training initiatives.

Carbon Nanotubes: Probabilistic Approach for Occupational Risk Assessment.

In this study, the occupational risk assessment of carbon nanotubes (CNTs) was performed by means of a probabilistic approach. Chronic and subchronic inhalation exposure studies were retrieved during the hazard identification phase of the study. These studies were then used to obtain a guidance value (BMCh, expressed as a lognormal distribution with geometric mean ± geometric standard deviation = 10.0 ± 4.2 µg/m3) for occupational inhalation exposure to CNTs. An exposure scenario was selected from the scientific literature: three different work events (WEs) related to the production of conductive films were considered: (WE1) manufacturing of single walled carbon nanotubes films during normal operation using local exhaust ventilation (LEV); (WE2) manufacturing of SWCNT film without LEV; and (WE3) cleaning of one of the reactors. For each WE, a probability distribution function was applied, considering exposure expressed as mass concentration, as derived from three different measurement techniques. The ratio of the exposure and the BMCh distributions (i.e., the risk characterization ratio-RCR) was used to calculate the probability of occurrence of a relevant occupational risk. All the considered WEs indicated the presence of a risk (i.e., RCR distributions ≥ 1); however, only WE2 resulted in a statistically significant level of risk.

Environmental and biological monitoring of personal exposure to air pollutants of adult people living in a metropolitan area.

BACKGROUND: Human exposure to air pollutants, and specifically to particulate matter (PM) and volatile organic compounds (VOCs), may pose a relevant risk on human health. AIM: To evaluate the personal exposure of adults living and working in Milan (Italy) by environmental and biological monitoring. METHODS: Personal exposure of 51 volunteer adults to PM2.5, PM2.5-10 and selected VOCs, including benzene, toluene, ethylbenzene, o-xylene, m + p-xylene, methyl tert-butyl ether, naphthalene, hexane, cyclohexane, heptane, and limonene was assessed along a 24-h period via personal cascade impactors and radial diffusive samplers. Urine spot samples were collected to investigate the corresponding urinary biomarkers. Time-activity patterns were filled in by participants to explore the performed activities. Multiple regression models were applied to investigate the association between personal exposure, biomarker levels, and tobacco smoke, traffic exposure, commuting mode, cooking activities, and personal characteristics. RESULTS: Median personal exposure to PM2.5, PM2.5-10, benzene, toluene, ethylbenzene o-xylene, m + p-xylene, methyl tert-butyl ether, naphthalene, hexane, cyclohexane, heptane, and limonene were 36.1, 7.8, 2.3, 7.8, 2.1, 1.8, 4.7, 0.8, 0.3, 1.4, 2.5, 1.6, and 59.9 µg/m3, respectively. Median levels of urinary benzene, toluene, ethylbenzene o-xylene, m + p-xylene, naphthalene, hexane, and heptane were 78.0, 88.1, 21.5, 15.2, 43.9, 21.0, 11.0, and 22.5 ng/L, respectively. For personal exposure, multiple regression models explained up to 67% (PM2.5) and 61% (benzene) of variability, with major contribution from commuting mode and environmental exposure. For biological monitoring, multiple regression analysis explained up to 74% of urinary benzene, with a major contribution given by creatinine, and secondary contributions by commuting mode, personal exposure to airborne benzene and smoking. CONCLUSIONS: Personal exposure to air pollutants was lower than that measured in the past in Milan. Personal exposure was mainly driven by traffic variables, while internal dose was mainly driven by personal characteristics and smoking habit.