Novel Multi-isotope Tracer Approach to Test ZnO Nanoparticle and Soluble Zn Bioavailability in Joint Soil Exposures

Adam Laycock*, Ana Romero-Freire, Jens Najorka, Claus Svendsen, Cornelis A.M. Van Gestel, Mark Rehkämper

*Corresponding author for this work

    Research output: Contribution to JournalArticleAcademicpeer-review


    Here we use two enriched stable isotopes, 68Znen and 64Znen (>99%), to prepare 68ZnO nanoparticles (NPs) and soluble 64ZnCl2. The standard LUFA 2.2 test soil was dosed with 68ZnO NPs and soluble 64ZnCl2 to 5 mg kg-1 each, plus between 0 and 95 mg kg-1 of soluble ZnCl2 with a natural isotope composition. After 0, 1, 3, 6, and 12 months of soil incubation, earthworms (Eisenia andrei) were introduced for 72 h exposures. Analyses of soils, pore waters, and earthworm tissues using multiple collector inductively coupled plasma mass spectrometry allowed the simultaneous measurement of the diagnostic 68Zn/66Zn, 64Zn/66Zn, and 68Zn/64Zn ratios, from which the three different isotopic forms of Zn were quantified. Eisenia andrei was able to regulate Zn body concentrations with no difference observed between the different total dosing concentrations. The accumulation of labeled Zn by the earthworms showed a direct relationship with the proportion of labeled to total Zn in the pore water, which increased with longer soil incubation times and decreasing soil pH. The 68Znen/64Znen ratios determined for earthworms (1.09 ± 0.04), soils (1.09 ± 0.02), and pore waters (1.08 ± 0.02) indicate indistinguishable environmental distribution and uptake of the Zn forms, most likely due to rapid dissolution of the ZnO NPs.

    Original languageEnglish
    Pages (from-to)12756-12763
    Number of pages8
    JournalEnvironmental Science and Technology
    Issue number21
    Publication statusPublished - 7 Nov 2017


    Katharina Kreissig and Barry Coles of the Imperial College MAGIC Laboratories and Rudo Verweij at the Vrije Universiteit are thanked for their technical assistance. The authors would also like to thank the three anonymous reviewers for their constructive comments. The work was in part supported by NERC grant NE/L004968/1, the EU FP7 project GUIDEnano (EU-CP-FP7604387), and the EU H2020 project NanoFASE under Grant Agreement no. 646002 (2015−2019) (H2020-NMP-2014).

    FundersFunder number
    EU FP7EU-CP-FP7604387
    EU H2020H2020-NMP-2014
    EU H2020 project2015-2019
    Horizon 2020 Framework Programme646002
    National Eye Research CentreNE/L004968/1


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