Occupational exposure during handling and loading of halloysite nanotubes – A case study of counting nanofibers

Antti Joonas Koivisto*, Anders Brostrøm, Kirsten Inga Kling, Ana Sofia Fonseca, Emile Redant, Flavia Andrade, Karin Sørig Hougaard, Maksym Krepker, Ofer Setter Prinz, Ester Segal, Andreas Holländer, Keld Alstrup Jensen, Ulla Vogel, Ismo Kalevi Koponen

*Corresponding author for this work

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    Abstract

    Halloysite nanotubes (HNTs) are abundant naturally-occurring hollow aluminosilicate clay mineral fibers with a typical diameter < 100 nm and an aspect ratio of up to 200. Here we assessed the potential inhalation exposure to HNTs in an industrial research laboratory. Inside a fume hood, ten times 100 g of HNTs were poured at rate of 0.5 kg min−1, which increased concentrations from the background level up to 2900 cm−3 and 6.4 μm2 cm−3. Inside the fume hood, the respirable mass concentration was 143 μgm−3 including background particles. Outside the fume hood we did not measure elevated concentrations. We classified 1895 particles according to their length and aspect ratio. Five particles were in aspect ratio > 3 and in length > 2 μm. These particles were agglomerated and/or aggregated particles where the longest individual fiber was 2 μm in length. The occupational exposure limits for refractory mineral fibers vary from 0.1 to 2 fibers cm−3. Following standard protocols for fiber analysis, detection of 0.1 fibers cm−3 would require analysis on 4×104 images when the filter loading is good. Thus, the fiber sampling and quantification procedures needs to be improved significantly if nanofibers < 100 nm in diameter are included in regulatory exposure assessment. Due to very limited toxicological information of HNTs we recommend avoiding inhalation exposure.
    Original languageEnglish
    JournalNanoImpact
    Volume10
    Pages (from-to)153-160
    ISSN2452-0748
    DOIs
    Publication statusPublished - 2018

    Cite this

    Koivisto, Antti Joonas ; Brostrøm, Anders ; Kling, Kirsten Inga ; Fonseca, Ana Sofia ; Redant, Emile ; Andrade, Flavia ; Hougaard, Karin Sørig ; Krepker, Maksym ; Prinz, Ofer Setter ; Segal, Ester ; Holländer, Andreas ; Jensen, Keld Alstrup ; Vogel, Ulla ; Koponen, Ismo Kalevi. / Occupational exposure during handling and loading of halloysite nanotubes – A case study of counting nanofibers. In: NanoImpact. 2018 ; Vol. 10. pp. 153-160.
    @article{8b899920ad1248868b2aa8218dbc23d1,
    title = "Occupational exposure during handling and loading of halloysite nanotubes – A case study of counting nanofibers",
    abstract = "Halloysite nanotubes (HNTs) are abundant naturally-occurring hollow aluminosilicate clay mineral fibers with a typical diameter < 100 nm and an aspect ratio of up to 200. Here we assessed the potential inhalation exposure to HNTs in an industrial research laboratory. Inside a fume hood, ten times 100 g of HNTs were poured at rate of 0.5 kg min−1, which increased concentrations from the background level up to 2900 cm−3 and 6.4 μm2 cm−3. Inside the fume hood, the respirable mass concentration was 143 μgm−3 including background particles. Outside the fume hood we did not measure elevated concentrations. We classified 1895 particles according to their length and aspect ratio. Five particles were in aspect ratio > 3 and in length > 2 μm. These particles were agglomerated and/or aggregated particles where the longest individual fiber was 2 μm in length. The occupational exposure limits for refractory mineral fibers vary from 0.1 to 2 fibers cm−3. Following standard protocols for fiber analysis, detection of 0.1 fibers cm−3 would require analysis on 4×104 images when the filter loading is good. Thus, the fiber sampling and quantification procedures needs to be improved significantly if nanofibers < 100 nm in diameter are included in regulatory exposure assessment. Due to very limited toxicological information of HNTs we recommend avoiding inhalation exposure.",
    author = "Koivisto, {Antti Joonas} and Anders Brostr{\o}m and Kling, {Kirsten Inga} and Fonseca, {Ana Sofia} and Emile Redant and Flavia Andrade and Hougaard, {Karin S{\o}rig} and Maksym Krepker and Prinz, {Ofer Setter} and Ester Segal and Andreas Holl{\"a}nder and Jensen, {Keld Alstrup} and Ulla Vogel and Koponen, {Ismo Kalevi}",
    year = "2018",
    doi = "10.1016/j.impact.2018.04.003",
    language = "English",
    volume = "10",
    pages = "153--160",
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    Koivisto, AJ, Brostrøm, A, Kling, KI, Fonseca, AS, Redant, E, Andrade, F, Hougaard, KS, Krepker, M, Prinz, OS, Segal, E, Holländer, A, Jensen, KA, Vogel, U & Koponen, IK 2018, 'Occupational exposure during handling and loading of halloysite nanotubes – A case study of counting nanofibers', NanoImpact, vol. 10, pp. 153-160. https://doi.org/10.1016/j.impact.2018.04.003

    Occupational exposure during handling and loading of halloysite nanotubes – A case study of counting nanofibers. / Koivisto, Antti Joonas; Brostrøm, Anders; Kling, Kirsten Inga; Fonseca, Ana Sofia; Redant, Emile; Andrade, Flavia; Hougaard, Karin Sørig; Krepker, Maksym; Prinz, Ofer Setter; Segal, Ester; Holländer, Andreas; Jensen, Keld Alstrup; Vogel, Ulla ; Koponen, Ismo Kalevi.

    In: NanoImpact, Vol. 10, 2018, p. 153-160.

    Research output: Contribution to journalJournal articleResearchpeer-review

    TY - JOUR

    T1 - Occupational exposure during handling and loading of halloysite nanotubes – A case study of counting nanofibers

    AU - Koivisto, Antti Joonas

    AU - Brostrøm, Anders

    AU - Kling, Kirsten Inga

    AU - Fonseca, Ana Sofia

    AU - Redant, Emile

    AU - Andrade, Flavia

    AU - Hougaard, Karin Sørig

    AU - Krepker, Maksym

    AU - Prinz, Ofer Setter

    AU - Segal, Ester

    AU - Holländer, Andreas

    AU - Jensen, Keld Alstrup

    AU - Vogel, Ulla

    AU - Koponen, Ismo Kalevi

    PY - 2018

    Y1 - 2018

    N2 - Halloysite nanotubes (HNTs) are abundant naturally-occurring hollow aluminosilicate clay mineral fibers with a typical diameter < 100 nm and an aspect ratio of up to 200. Here we assessed the potential inhalation exposure to HNTs in an industrial research laboratory. Inside a fume hood, ten times 100 g of HNTs were poured at rate of 0.5 kg min−1, which increased concentrations from the background level up to 2900 cm−3 and 6.4 μm2 cm−3. Inside the fume hood, the respirable mass concentration was 143 μgm−3 including background particles. Outside the fume hood we did not measure elevated concentrations. We classified 1895 particles according to their length and aspect ratio. Five particles were in aspect ratio > 3 and in length > 2 μm. These particles were agglomerated and/or aggregated particles where the longest individual fiber was 2 μm in length. The occupational exposure limits for refractory mineral fibers vary from 0.1 to 2 fibers cm−3. Following standard protocols for fiber analysis, detection of 0.1 fibers cm−3 would require analysis on 4×104 images when the filter loading is good. Thus, the fiber sampling and quantification procedures needs to be improved significantly if nanofibers < 100 nm in diameter are included in regulatory exposure assessment. Due to very limited toxicological information of HNTs we recommend avoiding inhalation exposure.

    AB - Halloysite nanotubes (HNTs) are abundant naturally-occurring hollow aluminosilicate clay mineral fibers with a typical diameter < 100 nm and an aspect ratio of up to 200. Here we assessed the potential inhalation exposure to HNTs in an industrial research laboratory. Inside a fume hood, ten times 100 g of HNTs were poured at rate of 0.5 kg min−1, which increased concentrations from the background level up to 2900 cm−3 and 6.4 μm2 cm−3. Inside the fume hood, the respirable mass concentration was 143 μgm−3 including background particles. Outside the fume hood we did not measure elevated concentrations. We classified 1895 particles according to their length and aspect ratio. Five particles were in aspect ratio > 3 and in length > 2 μm. These particles were agglomerated and/or aggregated particles where the longest individual fiber was 2 μm in length. The occupational exposure limits for refractory mineral fibers vary from 0.1 to 2 fibers cm−3. Following standard protocols for fiber analysis, detection of 0.1 fibers cm−3 would require analysis on 4×104 images when the filter loading is good. Thus, the fiber sampling and quantification procedures needs to be improved significantly if nanofibers < 100 nm in diameter are included in regulatory exposure assessment. Due to very limited toxicological information of HNTs we recommend avoiding inhalation exposure.

    U2 - 10.1016/j.impact.2018.04.003

    DO - 10.1016/j.impact.2018.04.003

    M3 - Journal article

    VL - 10

    SP - 153

    EP - 160

    JO - NanoImpact

    JF - NanoImpact

    SN - 2452-0748

    ER -