Trace Elements in Tears: Comparison of Rural and Urban Populations Using Particle Induced X-ray Emission

Olga Girshevitz, Noa Cohen-Sinai, Alon Zahavi, Yoav Vardizer, Dror Fixler, Nitza Goldenberg-Cohen

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


We aimed to evaluate the types and concentrations of trace elements in tears of individuals living in urban and rural environments using particle induced X-ray emission (PIXE) and the possible association with exposure to air pollution and suggest a novel method for tear-based biomonitoring studies. This cross-sectional pilot study comprised 42 healthy subjects, 28 living in a rural area and 14 in an industrial city. Tears were collected with Schirmer paper and characterized by PIXE. Trace element concentrations from both eyes were averaged together with environmental pollution data. Main outcome measures were between-group differences in types and concentrations of trace elements in tears and comparison to environmental data. The rural group included 12/28 men, mean age 45.2 ± 14.8 years. The urban group consisted of 11/14 men of mean age 27 ± 5.9 years. Six rural and all urban were active smokers. Air pollution data showed more toxic elements in the rural environment. On PIXE analysis, chlorine, sodium, and potassium were found in similar concentrations in all samples. Normalizing to chlorine yielded higher values of aluminum, iron, copper, and titanium in the rural group; aluminum was found only in the rural group. The higher levels of certain trace elements in the rural group may, in part, be a consequence of exposure to specific environmental conditions. No direct association was found with air pollution data. PIXE is useful to analyze trace elements in tears, which might serve as a marker for individual exposure to environmental pollutants in biomonitoring studies.

Original languageEnglish
Article number1633
JournalJournal of Personalized Medicine
Issue number10
StatePublished - 2 Oct 2022

Bibliographical note

Publisher Copyright:
© 2022 by the authors.


This research was partially supported by grants from the ZANVYL AND ISABELLE KRIEGER FUND, Baltimore, Maryland, USA; Grant 2509/21 from the Israel Science Foundation (NG-C).

FundersFunder number
Israel Science Foundation


    • Schirmer test
    • environmental pollution
    • particle-induced X-ray emission (PIXE)
    • tears
    • trace elements
    • urban vs. rural subjects


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