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MICROPLASTICS AN ANALYTICAL PERSPECTIVE
MICROPLASTICS AN ANALYTICAL PERSPECTIVE
Dr. Bob Symons
Regional Technical Manager Eurofins Environment Testing Australia & New Zealand
MICROPLASTICS AN ANALYTICAL PERSPECTIVE
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Microplastics (MPs) There is a lot of information under the surface!
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Microplastics
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• What are microplastics? • Particles in the size range 1 µm to < 5 mm. • Nanoplastics from ~1 to 100 nm (0.001 – 1µm).
• There is no legislation for microplastics and nanoplastics as contaminants in food including water.
• Microplastics can contain on average 4% of additives and the plastics can adsorb contaminants.
• Trophic transfer of contaminants, e.g., persistent organic pollutants (POPs), has been reported and biomagnification has been shown.
• Concentrations of up to 2,750 ng/g of PCB and 24,000 ng/g of PAHs have been found in microplastics deposited at beaches.
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Common types of plastics and their normal usage
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Type of Plastic Abbreviation Application of Virgin Resin Density (g cm-3)
Polyethylene terephthalate PET Disposable beverage bottles, textiles, (synthetic fibres), tape, Mylar food packaging and thermal insulation
1.37–1.38
High density polyethylene HDPE Plastic bags, plastic lumber, fuel tanks, bottle caps, milk crates 0.93–0.97
Polyvinyl chloride PVC Plumbing pipes, door and window frames, garden hoses, electrical cable insulation, inflatable products
1.10–1.47
Low density polyethylene LDPE Plastic bags and films six-pack rings, flexible Snap-On lids 0.91–0.92
Polypropylene (expanded or non-expanded)
PP Bottle caps, rope, carpet 0.89–0.92
Polystyrene (expanded or non-expanded) PS Disposable cutlery, dinnerware, and take-away food packaging, building insulation, refrigerated bins (e.g., fish & vegetable boxes)
0.28–1.04
Other resins, such as polycarbonate, nylon, polyamide, polymethylene methacrylate and acrylic
PC, PMMA, PA6 Other Used for engineering purposes because of their thermal, electrical and chemical properties. e.g., electrical wire insulation
1.15–1.22
A review of analytical techniques for quantifying microplastics in sediments, Joanne S. Hanvey, Phoebe J. Lewis, Jennifer L. Lavers, Nicholas D. Crosbie, Karla Pozo and Bradley O. Clarke, Anal. Methods, 2017, 9, 1369
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Categorisation
Foams Filaments
Granules Pellets
Films
Fragments
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Analysis Methods • Compound or stereo microscopy • Fluorescence microscopy • Scanning electron microscopy (SEM) • Py-GC-MS/TGA-GC-MS • Single point Raman IR (µRaman) • FTIR • ATR-FTIR • LDIR
Sampling
Extraction
Clean-up
Concentration
Particle Analysis Visual sorting
Main issues: • Sorting is operator
dependent • Very difficult and time
consuming for small particles
Typical Work Flow
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Sampling
Typical Work Flow
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Sampling
Typical Work Flow
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Sampling
Typical Work Flow
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Sampling
Typical Work Flow Topography
Meteorological Conditions
Biology
Demography & Socio-economy
Sedimentology
Sea Conditions
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Extraction Physical Separation
ABC Sydney: Harriet Tatham
Typical Work Flow
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Extraction Physical Separation
R.L. Coppock et al., Environmental Pollution 230 (2017) 829-837
Typical Work Flow
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Quality Assurance/Quality Control (QAQC) • Laboratory design includes positive
pressure and air-lock • Pass through locker • Laminar flow cabinet • Cotton laboratory coats • Nitrile gloves • Procedural blanks • Laboratory Control Samples (Sand spiked
with MPs)
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Typical Work Flow
Clean-up Wet Digesting
Acid Digestion • H3PO4 • HCl • HF • H2SO4 • HClO4 • HNO3 Alkaline Digestion • KOH • NaOH Enzymatic Digestion • Proteinase K Peroxide Digestion • H2O2 • NaClO
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Typical Work Flow
Clean-up Wet Peroxide
Oxidation (WPO)
• Add 20 mL of aqueous 0.05 M Fe(II) solution to the beaker containing the <0.3 mm size fraction of collected solids.
• Add 20 mL of 30% hydrogen peroxide. CAUTION: this solution can boil violently if heated >75oC.
• Let mixture stand on at room temperature for five minutes prior to proceeding to the next step.
• Add a stir bar to the beaker and cover with a watch glass. • Heat to 75oC on a hotplate. • As soon as gas bubbles are observed at the surface,
remove the beaker from the hotplate and place it in the fume hood until boiling subsides. If the reaction appears to have the potential to overflow the beaker, add distilled water to slow the reaction.
• Heat to 75oC for an additional 30 minutes. • If natural organic material is visible, add another 20 mL of
30% hydrogen peroxide. • Repeat until no natural organic material is visible. • Add ~6 g of salt (NaCl) per 20 mL of sample to increase the
density of the aqueous solution (~5 M NaCl). • Heat mixture to 75oC until the salt dissolves.
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Typical Work Flow
DW Extraction
Filtration
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Typical Work Flow
Analysis LDIR
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Laser Direct Infrared (LDIR)
• The Agilent 8700 LDIR reduces analysis time to only 2-60 minutes.
• LDIR particle sizes goes down to the diffraction limit, typically IR light in this region has a spatial resolution between 5-10 µm.
• The visible high magnification camera spatial resolution goes down to 1 µm.
• Intuitive visualization Clarity software also facilitates complex data interrogation and reporting, in a user-friendly way.
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Typical Work Flow
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Testing Australia
Typical Work Flow
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Typical Work Flow
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Area imaged = 3 × 3 mm Time to image = 5 min 13 s Pixel size = 5 µm N = 40 particles
Typical Work Flow
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<10 µm >10-20 µm >20-50 µm >50-100 µm
Polycaprolactone
Polyacrylic esters
Cellulose
Polymethylene methacrylate (PMMA).
Polyamide (PA)
Polystyrene (expanded or non-expanded), (PS)
Polypropylene (expanded or non-expanded) (PP)
Low density polyethylene (LDPE)
Polyvinyl chloride (PVC), carboxylated
Polyvinyl chloride (PVC)
Polyacrylamide
High density polyethylene HDPE)
Polyethylene terephthalate (PET)
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Eurofins MP DW Project
Largest known and most global MPs study performed
Drinking Water collected in 20 countries from all over the world with a total 400 samples
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Eurofins MP DW Project
DW collected from 21 sites from all over Australia
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Eurofins MP DW Project
DW collected from 21 sites from all over Australia
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Conclusions
Without proper analytical methods we cannot:
• Properly assess the amount of microplastics in the environment
• Delineate what are the most important sources
• Quantify impacts of microplastics including transfer of POPs and other emerging contaminants
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