microscopic anthropogenic particles methods for monitoring

Microscopic anthropogenic particles

– methods for monitoring and results from a survey

Kerstin Magnusson

Tallinn, 24 January 2013

The Marine Strategy Framework Directive

11 qualitative descriptors for determining

good environmental status

Descriptor 10 :

“Properties and quantities of marine litter do not cause

harm to the coastal and marine environment.”

IVL Swedish Environmental Research Institute

Member countries should have knowledge about

characteristics of litter in the marine and coastal

environment

This includes trends in the amount, distribution and,

where possible, composition of micro-particles

(in particular micro-plastics)

Descriptor 10


But there is still no consensus on –

• What matrix/marine habitats should be sampled

• How the sampling should be done

• How the material should be analysed

To detect both spatial and long-term

trends there is a need for standardized

methods

? IVL Swedish Environmental Research Institute

Definition of microscopic litter

Considerations when sampling microscopic litter

Presentation of a simple and cheap method for

sampling of microparticles in seawater.

Results from a field study along the Swedish

coast

Themes of the talk


Sources to marine microparticles


Primary sources:

Plastic industry

Secondary sources:

Breakdown of larger plastic items (e.g. ropes, fishing gear);

often caused by a combination of UV light and mecanical

abrasion

Discharge from sewage treatment plants

Storm water from urban environment and roads

Possible harmful effects by microparticles

• Microparticles may in themselves be toxic,

e.g. polycarbonate plastic which is made of bisphenol A;

polystyrene which is made of styrene.

• Microparticles may leak harmful additives, e.g. phtalates,

flame retardants.

• Other pollutants may adsorb to the surface of

microparticles, and the particles become vectors for the

pollutants.

• Mechanical damage may be caused by the presence of

the microparticles.


What matrix should be sampled?


”How much microscopic litter is there in the sea?”

• Beach sediment

• Surface water

• Water mass

• Sediments

Pelagic

”It depends on where you look!

So where should marine microlitter be sampled?

The boyancy differ between different

materials and also changes with time.

Probably the best matrix to

sample in monitoring programmes

Sediments are probably the

place for deposition of microlitter

The pelagic probably reflects a

more recent input of microlitter

What size range should be included in

”microparticles”?


Upper limit: 5 mm

Lower limit: ???

There is a need to define ”microlitter”

300 µm is a standard mesh

size in a plankton net used

for sampling of zooplankton.

300 µm often used

for practical reasons

You find what you are looking for

Size of particles in a water sample/sediment sample

Number of particles

small large 300 µm 10 µm


A filter with a smaller mesh size will

sample

more particles and different particles

The choice of lower size limit is important


Methods used for monitoring should

(if possible) be cheap and simple

Upper limit: 5 mm

Lower limit: ≈50 µm


Our suggestion:

The lower limit should be set so that the samples

can be analysed with a normal light microscope.

What methods should be used for sampling?


Most sampling in the water column is done with

plankton nets, or filtering sampled water onboard a

ship

Contamination is a huge risk!


Filtering equipment for

sampling ≥ 300 µm


Suction of water through a filter

minimizes the risk for contamination

Sampling of microparticles from land

Filtering equipment for sampling ≥ 10 µm


Submersible pump

Filter holder

How should we analyse microscopic litter?

Identification of microplastics

Plastic, natural polymeres (e.g.cotton) and biological

material may be separated by morphological

differences.

2. Examination with infrared spectroscopy (FT-IR)

Identifies the material. e.g. what kind of plastic

Plastic fibres have (e.g.):

• No visible cellular or organic structures

• The same diameter along the entire length

1. Examination with light microscopy/stereo microscopy

Fibers from waste water sludge

430x magnification in polarized light

Zubris & Richards, Env. Poll. 2005


a) cotton b) nylon c) polyester

Field studies of marine microparticles in

the water column

Off shore

Flödevigen–Hirtshals,

8 stations

Coastal waters

Norwegian border–Gävle,

22 stations


Field sampling in the water column

Size fraction

Water volume

Domination particles

Method for analysis

≥ 300 µm 2 m3 Fibres of plastic or natural polymeres (e.g. cotton)

Stereo microscope (1-40x) Fluorescence & polarization microscopy FT-IR (=infrared spectroscopy)

≥ 10 µm 5-10 litre Fibres of plastic or natural polymeres (e.g. cotton)

Black anthropogenic particles

Light microscopy (40-400x) Fluorescence & polarization microscopy (FT-IR spectroscopy)

SEM-EDX Melting point Solubility in organic solvents

0

1

2

3

4

5

6

Fib

res

m-3

≥ 300 µm

1.1 synthetic fibres m-3

1.7 natural polymeric fibres

of anthropogenic origin m-3

Synthetic fibres

Natural polymeric fibres

Results from field study along the Swedish coast


0.0

1.0

2.0

3.0

4.0

5.0

Fib

res

l-1 ≥ 10 µm

1800 fibres m-3 (synthetic and natural polymeric fibres)

Results from field study , Swedish coast


Spectra from FT-IR microscopy

Blue fibre of

polyamide

Red fibre

of

cellulose

Photo from light microscopy


All anthropogenic microparticles are not plastic


Plastic particles ≥300 µm in surface water (0-1.5 m)

Particle conc. Number per m3

Swedish coastal waters (our study) 1.1

California, coastal, before a storm 0.6

California, coastal, after a storm 18

California, off shore, before a storm 0.1

California, off shore, after a storm 1

G.L. Lattin et al. 2004, Mar Poll Bull

Results from Swedish waters compared

to a Californian study


Field sampling

Anthropogenic microfibres in faeces from

a deposit feeding polychaete, Melinna

cristata

Johansson, 2011, Master thesis

Murray and Cowie, 2011, Mar. Poll. Bull.

100 out of 120 (83%) crayfish (Nephrops norvegicus)

caught with trawl had plastic fibres in the gut

Polystyrene particles can be taken up by blue mussels

Browne et al. 2008, Env. Sci Tech.

Uptake over gut epithelium

Particle concentration in haemolymph

microscopic anthropogenic particles methods for monitoring

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