Anwendungssichere nanokohlenstoffbasierte Fasermaterialien/Nanocarbon-based fibrous substances that are safe for use

Bäger, Daphne; Plitzko, Sabine; Broßell, Dirk; Thim, Carmen; Dziurowitz, Nico; Wenzlaff, Daniela; Hutsch, Thomas; Weißgärber, Thomas; Rießelmann, J.

doi:10.37544/0949-8036-2020-07-08-7

Cited by 1 publication

(2 citation statements)

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“…Table 14 compiles information on the workplaces and sampling parameters and reports fiber counting results for the nearfield filter samples and the corresponding upper limit concentration estimates. Since microscale fibers were already included in the image evaluation rules, the analysis of the workplace samples WP13 and WP14 performed with our nanofiber-sensitive strategy revealed that a purely microscale fiber fraction caused the observed violation of the exposure limit value for WHO 20 -fibers [37]. For workplaces in which no WHO 20 product fibers were observed in the nearfield, no product fibers were found on personal or farfield samples, either.…”

Section: Discussionmentioning

confidence: 93%

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A Practicable Measurement Strategy for Compliance Checking Number Concentrations of Airborne Nano- and Microscale Fibers

et al. 2020

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Despite compelling reports on asbestos-like pathogenicity, regulatory bodies have been hesitant to implement fiber number-based exposure limits for biodurable nanoscale fibers. One reason has been the lack of a practicable strategy for assessing airborne fiber number concentrations. Here, a method is proposed, detailed and tested for compliance checking concentrations of airborne nano- and microscale fibers. It relies on Poisson statistical significance testing of the observed versus a predicted number of fibers on filters that have sampled a known volume of aerosol. The prediction is based on the exposure concentration to test. Analogous to the established counting rules for WHO-fibers, which use a phase contrast microscopy-related visibility criterion of 200 nm, the new method also introduces a cut-off diameter, now at 20 nm, which is motivated by toxicological findings on multi-walled carbon nanotubes. This cut-off already reduces the workload by a factor of 400 compared to that necessary for imaging, detecting and counting nanofibers down to 1 nm in diameter. Together with waiving any attempt to absolutely quantify fiber concentrations, a compliance check at the limit-of-detection results in an analytical workload that renders our new approach practicable. The proposed method was applied to compliance checking in 14 very different workplaces that handled or machined nanofiber-containing materials. It achieved detecting violations of the German benchmark exposure level of 10,000 nanofibers per cubic meter.

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Section: Discussionmentioning

confidence: 93%

“…Thus, extrapolation to shift values may be necessary. More results of this measurement campaign have been or will be reported in dedicated workplace-and material-related publications [37,40].…”

Section: Discussionmentioning

confidence: 99%