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We investigated airborne and internal exposure to manganese (Mn) and iron (Fe) among welders. Personal sampling of welding fumes was carried out in 241 welders during a shift. Metals were determined by inductively coupled plasma mass spectrometry. Mn in blood (MnB) was analyzed by graphite furnace atom absorption spectrometry. Determinants of exposure levels were estimated with multiple regression models. Respirable Mn was measured with a median of 62 (inter-quartile range (IQR) 8.4-320) μg/m(3) and correlated with Fe (r=0.92, 95% CI 0.90-0.94). Inhalable Mn was measured with similar concentrations (IQR 10-340 μg/m(3)). About 70% of the variance of Mn and Fe could be explained, mainly by the welding process. Ventilation decreased exposure to Fe and Mn significantly. Median concentrations of MnB and serum ferritin (SF) were 10.30 μg/l (IQR 8.33-13.15 μg/l) and 131 μg/l (IQR 76-240 μg/l), respectively. Few welders were presented with low iron stores, and MnB and SF were not correlated (r=0.07, 95% CI -0.05 to 0.20). Regression models revealed a significant association of the parent metal with MnB and SF, but a low fraction of variance was explained by exposure-related factors. Mn is mainly respirable in welding fumes. Airborne Mn and Fe influenced MnB and SF, respectively, in welders. This indicates an effect on the biological regulation of both metals. Mn and Fe were strongly correlated, whereas MnB and SF were not, likely due to higher iron stores among welders.

The significance of engineered nanomaterials (ENM) and nanotechnologies grows rapidly. Nanotechnology applications may have a positive marked impact on many aspects of on human every day life, for example by providing means for the production of clean energy and pure drinking water. Hundreds of consumer nano-based products are already on the market. However, very little is known of the risks of ENM to occupational safety and health (OSH), even though workers are likely to be at extra risk, as compared with other potentially exposed groups of people, because the levels of exposure are usually higher at workplaces than in other environments. However, knowledge of the exposure to, or effects of, ENM on human health and safety in occupational environments is limited and does not allow reliable assessment of risks of ENM on workers' health. Several issues related to ENM in the workplaces require marked attention. The most topical issues include: (1) improved understanding of ENM metrics associated with ENM toxicity; (2) development of monitoring devices for ENM exposure assessment; (3) understanding the changes of ENM structure and state of agglomeration at different concentrations in aerosols; (4) understanding translocation of ENM in the human body; (5) identifying the key health effects of ENM including pulmonary toxicity, genotoxicity, carcinogenic effects, and effects on circulation; (6) development of tiered approaches for testing of safety of ENM; and (7) utilizing these data for health risk assessment, with a special emphasis on occupational environment. Available data on several ENM - ability to enter the body and reach almost any organ, to cause pulmonary inflammation and fibrosis, and even to cause increased risk of mesotheliomas in animal models, call for immediate action. It is crucial to identify those ENM that may cause occupational health and safety risks from those ENM which are innocent, hence allowing prioritization of regulatory and preventive actions at workplaces at national, regional and global levels. © 2010 Elsevier Ltd.

In the past few years, an increasing number of studies on workplace air measurements on manufactured nano-materials and -objects have been published. Most of the studies had a more explorative character, so a direct interpretation to workers” exposure for a given exposure situation, activity, or process is not a straight-forward process. In general, the studies use a quite similar package of devices for near real-time monitoring of particle number- and mass concentration in size ranges

In this chapter the focus is on the risk assessment and management of first-generation passive nanomaterials at the workplace, neglecting commodity nanomaterials like fumed silica or carbon black as evidence, suggesting a special need to act for these, which have been on the market for several decades, that is to our knowledge lacking. We are also not aware that second-generation active nanomaterials have entered the market, despite a rise in publications on these materials. After outlining the basic principles for the handling of hazardous substances at the workplace, the hierarchy of control is delineated in a practical way for nanomaterials. Hereby we show that already for the handling of ordinary, larger dust particles a lot of control measures have to be implemented in a company. It is also shown that in general control measures that work for dust are actually efficient for the control of nanoparticles at the workplace, either in companies or in a laboratory environment. The imminent question of the appropriateness of control measures at a given workplace is discussed with reference to the concepts of recommended exposure limits or benchmark levels in different metrics and to existing occupational exposure limits for non-nano forms of hazardous substances. Finally, reference is made to how international chemical policy regulations deal with nanomaterials before briefly discussing the challenges ahead for the risk assessment and management of nanomaterials.

The production of nanomaterials and nano-enabled products is associated with the potential for workers' exposure to (manufactured) nano-objects' agglomerates and aggregates (NOAA). Workplace air monitoring studies have been conducted to assess the actual exposure; however, the methods and strategies applied to measure concentrations of NOAA in workplace air show substantial differences. In this chapter the major elements are outlined of a measurement strategy to assess exposure of workers to NOAA. The selection of the methods is a key issue to design an appropriate strategy to meet the objects of the measurement. The main principles of real-time aerosol monitoring and sampling for off-line analysis are presented and proposed strategies for measuring NOAA are discussed. Finally, the potential of the nanodevice pre-prototypes with respect to the various aims of measurement are discussed. © 2014 Elsevier Inc. All rights reserved.

Manufactured nano-objects, agglomerates, and aggregates (NOAA) may have adverse effect on human health, but little is known about occupational risks since actual estimates of exposure are lacking. In a large-scale workplace air-monitoring campaign, 19 enterprises were visited and 120 potential exposure scenarios were measured. A multi-metric exposure assessment approach was followed and a decision logic was developed to afford analysis of all results in concert. The overall evaluation was classified by categories of likelihood of exposure. At task level about 53 % showed increased particle number or surface area concentration compared to ‘‘background’’ level, whereas 72 % of the TEM samples revealed an indication that NOAA were present in the workplace. For 54 out of the 120 task-based exposure scenarios, an overall evaluation could be made based on all parameters of the decision logic. For only 1 exposure scenario (approximately 2 %), the highest level of potential likelihood was assigned, whereas in total in 56 % of the exposure scenarios the overall evaluation revealed the lowest level of likelihood. However, for the remaining 42 % exposure to NOAA could not be excluded.

The aim of this article is to present an overview of salient issues of exposure, characterisation and hazard assessment of nanomaterials as they emerged from the consensus-building of experts undertaken within the four year European Commission coordination project NanoImpactNet. The approach adopted is to consolidate and condense the findings and problem-identification in such a way as to identify knowledge-gaps and generate a set of interim recommendations of use to industry, regulators, research bodies and funders. The categories of recommendation arising from the consensual view address: significant gaps in vital factual knowledge of exposure, characterisation and hazards; the development, dissemination and standardisation of appropriate laboratory protocols; address a wide range of technical issues in establishing an adequate risk assessment platform; the more efficient and coordinated gathering of basic data; greater inter-organisational cooperation; regulatory harmonization; the wider use of the life-cycle approaches; and the wider involvement of all stakeholders in the discussion and solution-finding efforts for nanosafety. © 2013 by the authors. OA gold

This investigation aims to explore determinants of exposure to particle size-specific welding fume. Area sampling of ultrafine particles (UFP) was performed at 33 worksites in parallel with the collection of respirable particles. Personal sampling of respirable and inhalable particles was carried out in the breathing zone of 241 welders. Median mass concentrations were 2.48 mg m(-3) for inhalable and 1.29 mg m(-3) for respirable particles when excluding 26 users of powered air-purifying respirators (PAPRs). Mass concentrations were highest when flux-cored arc welding (FCAW) with gas was applied (median of inhalable particles: 11.6 mg m(-3)). Measurements of particles were frequently below the limit of detection (LOD), especially inside PAPRs or during tungsten inert gas welding (TIG). However, TIG generated a high number of small particles, including UFP. We imputed measurements

Preliminary results of inventories of exposure scenarios for nanomaterials have indicated possible dermal exposure. Within the NANOSH project focused on occupational safety and health aspects of nanotechnology a shortened version of the observational DeRmal Exposure AssessMent (DREAM) method was used as an initial method to assess dermal exposure. A total of 45 tasks (such as bagging, dumping, and cleaning) involving different manufactured nanoparticles (MNPs) such as carbon nanotubes, fumed silica, and cerium oxide, were observed in industrial and research facilities. In 39 tasks potential dermal exposure (that is, exposure of the skin and clothing) was likely to occur. Exposure resulted from different routes, including direct contact with MNPs as well as the deposition or transfer of MNPs. The survey showed it is both feasible and useful to assess the potential dermal exposure using shortened DREAM questionnaires.

Background: This paper presents the outcomes from a workshop of the European Network on the Health and Environmental Impact of Nanomaterials (NanoImpactNet) held in June 2008. During this workshop 45 experts in the field of safety assessment of engineered nanomaterials from academia, non-profit organizations and industry addressed a list of essential metrics of engineered nanomaterials that need to be characterized as a minimum. Results: The group discussed the need to systematically study sets of engineered nanomaterials to generate a dataset that allows for the establishment of dose-response data related to specific metrics of engineered nanomaterials. Concomitantly the availability of analytical methods to determine the physicochemical characteristics was discussed. Given the measurement challenges specific for engineered nanomaterials the issue of harmonizing protocols was raised. Conclusion: The group concluded that international cooperation and worldwide standardization of terminology, reference materials and protocols are needed to make progress in establishing lists of essential metrics. The need for high quality data necessitates the development of harmonized study approaches and adequate reporting of data. Priority metrics can only be based on well-characterized dose-response relations (as regards biological interactions and physiochemical characteristics) of engineered nanomaterials. This requires the systematic study of the biokinetics and biointeractions of nanomaterials at both organism and (sub)cellular levels. Additionally, much effort needs to be put into the standardization and validation of analytical methods to determine these metrics. Especially for the characterization of engineered nanomaterials in a complex matrix much work needs to be done.

Objectives Siderosis due to excessive iron exposure is a rare disease in welders. Less is known about the effect of inhaled iron on systemic iron status in welders. Here we present the association between exposure to iron as major constituent of the welding fume and the iron status in German welders. Method In this analysis we included 192 welders from the German WELDOX study not wearing respirators. Respirable welding fume was measured during one shift and analysed for its metal content. Iron status was assessed with different measures, including serum iron, serum ferritin (SF), transferrin, and prohepcidin. High iron stores were classified according to international standards. The influence of exposure to iron and other factors on the iron status was analysed with multiple regression models. Results Median shift exposure to respirable iron was 88 µg/m³ (interquartile range 13–690 µg/m³). For the overall study population the prevalence of high iron stores (SF > 200 µg/L) was 31.3%. A lower prevalence was found for tungsten inert gas (TIG) welders (16.9%). For all other welders using welding techniques with higher emission rates it was 38.6%. The regression models revealed a significant association of respirable iron and prohepcidin (exp (β)=1.08, 95% CI 1.05; 1.11) and a weaker association between respirable iron and serum ferritin (exp (β)=1.06, 95% CI 1.00; 1.12). Conclusions Although the iron status is biologically well regulated we found positive associations of respirable iron in welding fumes on prohepcidin and ferritin. We observed more welders with high iron stores in comparison to male persons from the general population.

Objectives The aim of this analysis was to explore exposure to welding fumes and potential influencing factors of the airborne concentrations. Methods Personal sampling of welding fumes was carried out in 241 welders. Ninety respirable dust measurements were below the limits of detection (LOD). Therefore, we applied Tobit regression and imputations of values below LOD according to the log-normal distributions of the data ≥LOD with maximum likelihood estimation. We estimated regression coefficients for the welding processes, protective measures, and other factors. Results Main determinant of the concentrations was the type of welding process. The use of flux-cored wire in gas metal arc welding was estimated to increase the concentration in comparison with gas metal arc welding with solid wire (GMAW) by a factor of 2.20 (95% CI 1.58 to 3.06) using Tobit regression and by 2.36 (95% CI 1.51 to 3.69) using imputation. Tungsten inert gas welding was associated with 0.15 fold lower levels than with GMAW in both models. Dust extraction reduced the concentrations, whereas welding in confined space increased exposure levels with significant effects in both approaches. Conclusions Exposure to respirable welding fumes was frequently found below LOD. Two different approaches to deal with data

Objectives This investigation aimed to estimate predictors and associations of airborne and systemic exposure to manganese (Mn) and iron (Fe) among welders. Methods Personal air sampling of welding fumes was carried out in 241 welders during a shift. Metals were determined in the respirable and inhalable particle fraction. Mn in blood (MnB) and serum ferritin (SF) were determined in post-shift samples. The exposure variables were log-transformed for the estimation of predictors with multiple regression models. Results Respirable Mn ranged up to 2400 µg/m 3 (median 62 µg/m 3 ) and comprised 82% of the concentrations in the inhalable fraction. Inhalable Fe was twofold higher than respirable Fe. Mn was correlated with Fe (respirable fraction: r=0.92). Statistical modelling revealed a good model fit for both metals in the welding fumes. The concentrations were mainly predicted by the type of welding process and modified by workplace characteristics. Model building revealed an influence of the parent metal on MnB and SF, respectively. However, internal exposure levels were only weakly influenced by welding-related factors due to biological regulation. Median MnB was 10.30 µg/l, median SF 131 µg/l. MnB and SF were not correlated (r=0.08). Conclusions Welding resulted in similar Mn concentrations in both particle fractions of welding fumes, whereas inhalable Fe was twofold higher than respirable Fe. Biological regulation may at least partially explain the lack of association between MnB and SF. Mechanisms underlying Mn organ distribution and neurotoxicity need to be evaluated.