Adsorption of microplastic to macroalgae Fucus vesiculosus · 2016. 10. 26. · Adsorption of microplastic to macroalgae Fucus vesiculosus Nanna B. Hartmann1*, Clara G. Villaro1,

Adsorption of microplastic to macroalgae Fucus vesiculosus

Nanna B. Hartmann1*, Clara G. Villaro1, Ida D. W. Koch1, Kasper B. Sundbæk1, Niclas S. Rasmussen1, Susan L. Holdt2

1 DTU Environment, Technical University of Denmark2 The National Food Institute, Technical University of Denmark

*Email: [email protected]

09 October 2016DTU Environment, Technical University of Denmark

My background…

Ecotoxicology and effects of particle pollutants (nano- and microparticles)

2 For macro-algae specific questions….


Microplastics

3 24 October, 2016


Microplastics

• Tiny fragments, pellets or fibres of plastics

• Often defined as having a size of <5mm (In comparison: sand grains are <2mm)

• Microplastics are abundant! They have been found in all oceans, on all continents – in the deep sea and in coastal waters

• Originates from primary sources and secondary sources

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Primary and secondary sources of microplastics

5

Rist & Hartmann, 2016, Aquatic ecotoxicity of microplastics and nanoplastics - lessons learned from nanoecotoxicology, submitted

E.g. Granules from plastic manufacturing industry and logistics, cosmetics)

E.g. degradation of fishing gear, shipping waste, littering at beaches, uncontrolled landfill in coastal areas and along rivers, car tyre particles...


Sources of microplastics

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Primary sources

24 October, 2016


“There are over 150 million tonnes of plastics in the ocean today. In a business-as-usual scenario, the ocean is expected to contain 1 tonne of plastic for every 3 tonnes of fish by 2025, and by 2050, more plastics than fish (by weight).”

(World Economic Forum,

The New Plastics Economy

- Rethinking the future of plastics, 2016)

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Effects of microplastics

• Limited knowledge on effects on marine and freshwater organisms.

• Physical effects: When animals erroneously ingest micro plastic instead of the feed - may lead to reduced food intake .

• Toxic effects of additives: When the harmful substances ,that are added to the plastics, are released.

• Micro Plastics as a 'carrier' for other pollutants: When other environmental contaminants adsorb to micro plastic and are transported with them. This may affect the uptake of pollutants in aquatic animals.

• Impact on the image of marine food products!

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09 October 2016DTU Environment, Technical University of Denmark9

Photo credit: Marcus Erikson, 5-Gyres Institute


Fucus vesiculosus (bladder wrack) as food source

• Abundant along all Danish shores

• One of the most common types of edible seaweed in Denmark

• Can be purchased dried as whole plants, in flakes and powder

• Added in as ingredient in products such as pesto

• Used in many recent seaweed recipes

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Fucus vesiculosus (bladder wrack) & microplastics

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Image: Azote.se

Images: www.Azote.se

“We showed that the benthic seaweed F. vesiculosus can retain suspended microplastics on its surface, thereby making them available for herbivorous consumers”

“The transfer of microplastics from benthic primary producers to consumers may represent a so-far underestimated pathway for the entry of microplastics into coastal food webs”


The aim of this study

• To investigate if microplastic adsorb to macroalgae Fucusvesiculosus and thereby pose a threat to the use of ”seaweed” in foods.

• Investigations:

– Do fluorescent polystyrene (PS) microplastics adsorb to the surface of F. vesiculosus?

– Will adsorped microlastic particles be washed of by filtered seawater (rinsing procedures are common before food application)

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Collection of seaweed

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Just South of Bellevue beach, Copenhagen, DK

GPS coordinates: 55,771873; 12,596503

June 2016


This study - experimental design

• Algal pieces (distal tips, length 6-7 cm) exposed to defined concentrations of fluorescent polystyrene (PS) particles (size: 20 μm, Ex.: 450nm Em.: 500nm , Phosphorex) suspended in seawater.

• A total of four tips were placed in a bluecap glass bottle with 50 mL of filtered (0.45 μm) seawater and 2.65 mg/L PS (~600.000 particles/L). Samples were prepared in quadruplicate.

– A) Samples were agitated for 2h in a rotation box (1 rpm)

– B) Samples were transferred to clean seawater and agitated for 1h

• All experiments were carried out at 10°C

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Comparison to environmental concentrations of microplastics

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4-94 particles/L

>10 um,

Norén et al 2014

64-194 particles/L

>1.2 um,

Dubaish and Liebezeit 2013

1.7 particles/L

>10 um,

Norén & Naustvoll(2010

Collection of seaweed

GPS coordinates: 55,771873;12,596503


Counting adsorbed microplastics

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1 2

3


Results

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Particles pr. cm

After exposure (avg)

After rinsing

Bottle Gradient Gradient

No. 1 2 3 1 2 3

P1 13 7 8 1 2 2

P1 12 5 7 1 1 0

P3 10 6 3 2 1 0

P4 10 4 3 2 0 1

K5 0 0 0 0 0 0

K6 0 0 0 0 0 0

K7 0 0 0 0 0 0

K8 0 0 0 0 0 00

2

4

6

8

10

12

14

1 2 3

Nu

mb

er o

f p

arti

cle

s p

r c

m

Gradient

After exposure After rinsing

1 2

3


Results

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0

2

4

6

8

10

12

1 2 3

Nu

mb

er o

f p

arti

cle

s p

r c

m

Gradient

After exposure After rinsing

** ****

1 2

3

(Welch) two-sample t-test ***: P ≤ 0.001, **: P ≤ 0.01: *: P ≤ 0.05


Results

• Clear reduction in the number of adsorbed microplastics after rinsing. However, some particles are still attached

• Fewer particles adsorbed to the bladders compared to the rest of the surface. May be related to a difference in surface structure

• Tendency to higher number of adsorbed particles onto seaweed collected in June compared to seaweed collected in April. Indication of temporal variations? Related to changes in alginate content? Further investigation needed…

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Conclusions

• Microplastic particles are able to adsorb to the surface of macroalgaeFucus vesiculosus

• Our results indicate that the adsorption is related to the surface structure of the macroalgae and possibly temporal variations in alginate content

• By rinsing the algae in clean filtered seawater for 1 hours 81-86% of the adsorbed microplastic particles could be removed. However, some were still found on the algae surface.

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Conclusions

• Experiments were carried out at concentrations MUCH higher than environmental microplatsic concentrations. However:

• Our results indicate that further studies may be relevant to

– investigate the adsorption of microplastics to macroalgae in real environmental samples.

– to explore the efficiency of different rinsing techniques for the removal of microplastics from seaweed for use in food.

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09 October 2016DTU Environment, Technical University of Denmark22

Clara

IdaKasper

Niclas


Thank you for your attention!

23 24 October, 2016

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Adsorption of microplastic to macroalgae Fucus vesiculosus · 2016. 10. 26. · Adsorption of microplastic to macroalgae Fucus vesiculosus Nanna B. Hartmann1*, Clara G. Villaro1,