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ASSESSMENT OF MICROPLASTIC CONCENTRATIONS IN HUMAN STOOL
FINAL RESULTS OF A PROSPECTIVE STUDY
ASSESSMENT OF MICROPLASTIC CONCENTRATIONS IN HUMAN STOOL
FINAL RESULTS OF A PROSPECTIVE STUDY
Bettina Liebmann1, Sebastian Köppel1, Philipp Königshofer2, Theresa Bucsics2, Thomas Reiberger2 and Philipp Schwabl2
1 Environment Agency Austria (Umweltbundesamt GmbH), Spittelauer Lände 5, 1090 Vienna, Austria. bettina.liebmann@umweltbundesamt.at
2 Div. of Gastroenterology & Hepatolology, Dept. of Internal Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
The microplastics literature provides evidence that tiny plastic particles are accumulating in the marine food chain. Scientists have also detected
microplastics in food intended for human consumption such as salt or bottled drinks. It has been long suspected that humans are orally exposed to
microplastics via their diet. This pilot study was conducted with eight participants from across the globe. Each person kept a food diary in the week
leading up to their stool sampling. This first study of its kind did confirm that plastics are unintentionally ingested and ultimately reach the human
gut.
8 healthy male and female participants from AT, FI, UK, IT,
JP, NL, PL and RU
Exclusion criteria: diagnosed gastrointestinal disease, recent
dental treatment, medical diets, alcohol abuse and intake
of drugs affecting stool frequency, consistency or
resorption.
Pre-Treatment of Human Stool Samples
SAMPLE PRE-TREATMENT
Conference on Nano and microplastics in technical and freshwater systems, Microplastics 2018, 28-31 October 2018, Monte Verità, Ascona, Switzerland
Do microplastics reach the human gut?
Participants
Conclusion & Outlook
Data collection and sampling
Food log to track 6-7 days prior to sampling
Questionnaires on plastic exposure, alcohol
consumption, chewing gum consumption,
cosmetics, drinking habits from PET bottles
Sampling of ~50 g stool
All images ©Umweltbundesamt, unless otherwise stated.
©Medical University of Vienna / P. Königshofer
Stool samples and blanks before (above) and after 2 weeks (below)
of H2O2 (hydrogen peroxide) treatment.
Aims at reducing the amount of natural stool constituents.
After 2 weeks, still a fair amount of solids was left.
Separation of solids into fractions 0.05-0.5 and > 0.5 mm
Coarse fraction of pre-treated
stool (> 0.5 mm) with seeds, fibres,
fluff and thin-layered fragments
remaining.
ATR-FTIR measurements,
no > 0.5 mm plastics detected
FT-IR IMAGING EXAMPLE
Stool residues of size 0.05-0.5 mm
Left: Photograph of analytical sample
Right: FT-IR transmission images
correlation R² with plastics is color-coded;
here: Polyethylene , R² = 0.7-0.9.
Too many false positives for microplastics caused by
interfering biological material that was still remaining
after pre-treatment.
Fine fraction of pre-treated stool
(0.05-0.5 mm) with small
particles, fibres and fluff
remaining.
FTIR measurements in
transmission with imaging
Detection of Microplastics by FT-IR Spectroscopy and Imaging
NEXT STEP: IDENTIFY MATERIAL OF SOLID REMAINS
AND TEST FOR THE PRESENCE OF MICROPLASTICS:
Polyethylene (PE), Polypropylene (PP), Polyamide
(PA), Polyvinylchloride (PVC), Polystyrene (PS),
Polyethylenterepththalate (PET), Polyurethane (PU),
Polymethylmethacrylate (PMMA), Polycarbonate
(PC), Polyoxymethylene (POM).
ADVANCED SAMPLE PREPARATION MADE
QUANTIFICATION POSSIBLE!
Additional
chemical/enzymatic
procedures
Final Results
DESCRIPTIVE STATISTICS
Assessment of contamination caused by lab:
No microplastic particles > 50 µm (10 plastic
materials listed above) detected in blank sample.
Microplastics reach the human gut and are
(partly?) excreted with the stool.
The present pilot study included only a small
sample size for first screening in humans.
The analytical procedures are now available
for human stool screening.
Expand work to a study with a larger number
of participants.
Refine study design for investigating plastic
exposure and medical implications.
Plan for analytical validation experiments
using microplastic reference material.
1 particle
identified as
Polyethylene.
©https://commons.wikimedia.org/wiki/File:Relief_map_of_Eurasia.png
FI
NL
PL
AT
IT
UK
RU
JP
STOOL RESIDUES FOR ANALYSIS
3 male and 5 female participants, aged 33-65 yrs
0/8 vegetarians
2/8 daily chewing gum users
6/8 ingested sea food during observation period
8/8 contact with plastic-wrapped food
~ 750 ml/day beverage consumption from PET
20 microplastic particles/10 g stool (median)
(Q1-Q3: 18-172)
of size 50-500 µm
8/8 samples tested positive for microplastics
9/10 plastic types detected overall
3-7 different plastic types per sample
7 g stool analysed (median) (Q1-Q3: 3-11)
STOOL ANALYSIS
RELATIVE FREQUENCIES OF MICROPLASTIC TYPES
•PP and PET were found in 100% of samples (*)
PP, PET, PS and PE were found in >95% of
samples
Successful reduction of biological matrix so that the
masking effect is diminished considerably.
Automated FT-IR image analysis results in fewer false
positives.
Additional expert check of each particle’s IR spectra
is crucial for setting reasonable correlation
thresholds.