Microplastics: Understanding sources and impacts in freshwaterKatie Whitlock

Senior Scientist (Fisheries)

16th October 2017

Trend in plastic production

• In 2017, plastic production in Europe is expected to continue a moderately positive (+1.5%) trend

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Source: PlasticsEurope 2016

Plastic facts

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8.3 billion metric

tons

PLASTIC10 X

6 X

What are microplastics?

• Microplastics: particles <5mm down to microscopic particles

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• Primary microplastics: originally manufactured as such (or entering the environment at small size?)

• Secondary microplastics: resulting from breakdown of larger plastic items

• Large no. publications

• Addressed in MSFD (Descriptor 10: Marine Litter)

Freshwater lagging behind?

• Very few publications

• Not covered by WFD or HSD (yet)

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98% of losses of primary microplastics are from land-based activities (IUCN, 2017)

Source: Blair et al. (2017), Springer Science Reviews

What do we know about freshwater:Sources & pathways

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Source: IUCN (2017) Primary microplastics in the oceans: a Global evaluation of sources

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• What about the other 52%?

> Retained in soil

> Retained in sewage sludge

> Lost to freshwater ecosystems / biota / sediments?

Releases of microplastics: Marine

released into the oceans

Releases of microplastics: Freshwater• Waste water treatment

processing removes in excess of 90% of microplastics (e.g. Murphy et al, 2016 – River Clyde)

• Large quantities still released due to high through-put

• So for Murphy study, 98.41% removal but release 65 million microplastic particles everyday.

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Source: Danish Environmental Protection Agency (2015)

Microplastics in freshwater

• River and Lakes in;• Austria (Danube River)

• France (Rivers Marne & Seine)

• Germany (Rivers Rhine, Weser, Main, Elbe)

• Italy (Lake Garda)

• Netherlands (Rivers Meuse & Rhine, Lake Ijssel)

• Switzerland (Rhine River & Lake Geneva)

• United Kingdom (River Thames)

• USA & Canada (Great Lakes & Lake Ontario)

• Abundance influenced by factors such as urbanisation and waste management.

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Microplastics in sludge and soil• 10Mt/yr of organic wastes (incl. biosolids and

composts) applied to farmland

• Estimated to include >100 kt of microplastics(Nizetto et al. 2016)

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Plastics in compost (from Bläsing and Amelung 2018)

Earthworms concentrate finer microplastic

particles in their casts (from Lwanga et al. 2016)

What do we know about freshwater microplastics?

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Sources Pathways Fate

Impacts of microplastics: Direct

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Physical blockage / false satiation

Irritation / immune response / energy burden

Plasticizers / flame retardants / base materials

Lu et al, 2016

Impacts of microplastics: Indirect

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Source: McCormick et al (2014) Environmental

Science & Technology

Vector transport - chemicals

Vector transport - pathogens

Environment Agency research

• Experiment I: Exposure of larval stickleback to microplastic spheres

• Experiment II: Trophic transfer of microplasticspheres

• Experiment III: Microplastics as potential transport vectors for organic pollutants

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Impacts of microplastic exposure in fish

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Experiment I

Experiment II

Evidence of impacts • Ingestion and egestion documented for

large number of species – so what?

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Reduced productivity

Metrics of condition

Reduced feeding

Behavioural changes Source: Mattsson et al. 2017 Scientific

reports

Summary of evidence

• We know…

• Microplastics abundant in freshwater environment –BUT don’t know types, sources, fate.

• Sources of them likely to increase – BUT no reference point

• They are consumed by freshwater biota – BUT not clear on consequences

• They are transferred through the foodchain – BUT not clear on consequences

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What are the key evidence challenges?

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Basic /

immediate

Intermediate /

medium-term

Complex /

longer-term

Source: Wagner et al (2014) Environmental

Sciences Europe

Evidence challenges….dose-response

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Source: Lenz et al (2016) PNAS

What are we doing?• Workshops – first in Nov 2016

• Linking with Universities and research institutions

• Investigation planning with water companies

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