Occupational Exposure to Nano-Objects and Their Agglomerates and Aggregates Across Various Life Cycle Stages; A Broad-Scale Exposure Study

Bekker, Cindy; Kuijpers, Eelco; Brouwer, D.H.; Vermeulen, Roel; Fransman, Wouter

doi:10.1093/annhyg/mev023

Cited by 36 publications

(71 citation statements)

References 37 publications

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“…A number of studies demonstrated the potential of occupational exposure to CNTs during activities with CNTs (Maynard et al, 2004;Bello et al, 2008;Han et al, 2008;Yeganeh et al, 2008;Bello, 2009;Tsai et al, 2009;Johnson et al, 2010;Methner et al, 2010;Bello et al, 2010;Lee et al, 2010;Wang and Pui, 2011;Ogura et al, 2011;Dahm et al, 2012;Methner et al, 2012;Takaya et al, 2012;Fleury et al, 2013;Hedmer et al, 2014;Bekker et al, 2015;Dahm et al, 2015). The assessment is complicated as it is difficult to find a sensitive and selective analytical method for CNTs.…”

Section: Introductionmentioning

confidence: 99%

Occupational Exposure to Multi-Walled Carbon Nanotubes During Commercial Production Synthesis and Handling

Kuijpers

Bekker

Fransman

et al. 2015

ANNHYG

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The world-wide production of carbon nanotubes (CNTs) has increased substantially in the last decade, leading to occupational exposures. There is a paucity of exposure data of workers involved in the commercial production of CNTs. The goals of this study were to assess personal exposure to multi-walled carbon nanotubes (MWCNTs) during the synthesis and handling of MWCNTs in a commercial production facility and to link these exposure levels to specific activities. Personal full-shift filter-based samples were collected, during commercial production and handling of MWCNTs, R&D activities, and office work. The concentrations of MWCNT were evaluated on the basis of EC concentrations. Associations were studied between observed MWCNT exposure levels and location and activities. SEM analyses showed MWCNTs, present as agglomerates ranging between 200 nm and 100 µm. Exposure levels of MWCNTs observed in the production area during the full scale synthesis of MWCNTs (N = 23) were comparable to levels observed during further handling of MWCNTs (N = 19): (GM (95% lower confidence limit-95% upper confidence limit)) 41 μg m −3 (20-88) versus 43 μg m −3 (22-86), respectively. In the R&D area (N = 11) and the office (N = 5), exposure levels of MWCNTs were significantly (P < 0.05) lower: 5 μg m −3 (2-11) and 7 μg m −3 (2-28), respectively. Bagging, maintenance of the reactor, and powder conditioning were associated with higher exposure levels in the production area, whereas increased exposure levels in the R&D area were related to handling of MWCNTs powder.

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Section: Introductionmentioning

confidence: 99%

Occupational Exposure to Multi-Walled Carbon Nanotubes During Commercial Production Synthesis and Handling

Kuijpers

Bekker

Fransman

et al. 2015

ANNHYG

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“…Downstream activities that may release nanomaterials include bag dumping, manual transfer between processes, mixing or compounding, powder sifting, and machining of parts that contain nanomaterials. Bekker et al summarized the findings of exposure assessments conducted in 15 downstream nanomaterial usage (nonproduction) companies in the Netherlands (Bekker et al 2015). In these companies, across a range of industries, measurements showed that the highest exposure processes included the replacement of intermediate bulk material containers (aka big bags), mixing/dumping of powders, and the spraying of nanomaterial-containing liquids.…”

Section: Introductionmentioning

confidence: 99%

Performance of particulate containment at nanotechnology workplaces

Tsai

Dunn

et al. 2015

J Nanopart Res

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The evaluation of engineering controls for the production or use of carbon nanotubes (CNTs) was investigated at two facilities. These controls assessments are necessary to evaluate the current status of control performance and to develop proper control strategies for these workplaces. The control systems evaluated in these studies included ventilated enclosures, exterior hoods, and exhaust filtration systems. Activity-based monitoring with direct-reading instruments and filter sampling for microscopy analysis were used to evaluate the effectiveness of control measures at study sites. Our study results showed that weighing CNTs inside the biological safety cabinet can have a 37% reduction on the particle concentration in the worker’s breathing zone, and produce a 42% lower area concentration outside the enclosure. The ventilated enclosures used to reduce fugitive emissions from the production furnaces exhibited good containment characteristics when closed, but they failed to contain emissions effectively when opened during product removal/harvesting. The exhaust filtration systems employed for exhausting these ventilated enclosures did not provide promised collection efficiencies for removing engineered nanomaterials from furnace exhaust. The exterior hoods were found to be a challenge for controlling emissions from machining nanocomposites: the downdraft hood effectively contained and removed particles released from the manual cutting process, but using the canopy hood for powered cutting of nanocomposites created 15%–20% higher ultrafine (<500 nm) particle concentrations at the source and at the worker’s breathing zone. The microscopy analysis showed that CNTs can only be found at production sources but not at the worker breathing zones during the tasks monitored.

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“…As a direct consequence of such quality studies, the amount of available exposure data is increasing rapidly, and therefore, the field is becoming more sophisticated. In 2015, two studies were published that compared numerous sites and sampling events to derive high-confidence conclusions (Bekker et al 2015; Dahm et al 2015); Bekker et al were able to define the highest-exposure task in their study. Such a comprehensive sampling strategy, consistently applied and using a multifaceted methodology, represents the future of occupational nanoparticle exposure assessment.…”

Section: Exposure Assessmentmentioning

confidence: 99%

“…4. Despite these advances, the body of published exposure data focuses extensively on CNTs and TiO 2 and, to a lesser extent, on a few other commercial nanomaterials, such as noble metals (silver), metals and metallic oxides (iron, zinc, aluminum), carbon black, and other carbonaceous materials, such as fullerenes (Bekker et al 2015; Brouwer 2010; Kuhlbusch et al 2011). There remains a need to expand investigations of exposures to other types of ENMs, such as multilayered or functionalized nanoparticles.…”

Section: Exposure Assessmentmentioning

confidence: 99%

Taking stock of the occupational safety and health challenges of nanotechnology: 2000–2015

Pa¹,

Roth²,

Hodson³

et al. 2016

J Nanopart Res

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Engineered nanomaterials significantly entered commerce at the beginning of the 21st century. Concerns about serious potential health effects of nanomaterials were widespread. Now, approximately 15 years later, it is worthwhile to take stock of research and efforts to protect nanomaterial workers from potential risks of adverse health effects. This article provides and examines timelines for major functional areas (toxicology, metrology, exposure assessment, engineering controls and personal protective equipment, risk assessment, risk management, medical surveillance, and epidemiology) to identify significant contributions to worker safety and health. The occupational safety and health field has responded effectively to identify gaps in knowledge and practice, but further research is warranted and is described. There is now a greater, if imperfect, understanding of the mechanisms underlying nanoparticle toxicology, hazards to workers, and appropriate controls for nanomaterials, but unified analytical standards and exposure characterization methods are still lacking. The development of control-banding and similar strategies has compensated for incomplete data on exposure and risk, but it is unknown how widely such approaches are being adopted. Although the importance of epidemiologic studies and medical surveillance is recognized, implementation has been slowed by logistical issues. Responsible development of nanotechnology requires protection of workers at all stages of the technological life cycle. In each of the functional areas assessed, progress has been made, but more is required.

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Occupational Exposure to Nano-Objects and Their Agglomerates and Aggregates Across Various Life Cycle Stages; A Broad-Scale Exposure Study

Cited by 36 publications

References 37 publications

Occupational Exposure to Multi-Walled Carbon Nanotubes During Commercial Production Synthesis and Handling

Occupational Exposure to Multi-Walled Carbon Nanotubes During Commercial Production Synthesis and Handling

Performance of particulate containment at nanotechnology workplaces

Taking stock of the occupational safety and health challenges of nanotechnology: 2000–2015

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