Microplastics and Drinking Water -Current research and future research needsJennifer Hughes, Environmental Advisor, Thames WaterJohn Haley, Water Quality Strategy Manager, Yorkshire Water

- Both Research Programme Leads for UK Water Industry Research Ltd

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Content

• Background

• Recent research on microplastics in Drinking Water

• Gaps identified in our understanding

• Current plans for research in this area

• Identifying the future research and intervention needs

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Microplastics in water 'don't appear to pose health risk to humans', study claims – (Mirror online -26/08/19)

Based on the findings, the World Health Organisation (WHO) is calling for further research into the health risks posed by microplastics in drinking water:-

• Microplastics are now ubiquitous in the natural world and as well as being present in oceans and freshwater ways, they are now commonly found in drinking water from the tap and bottled water.

• In a newly-published report, WHO scientists say the limitations of current data mean it is difficult to gauge the potential impact on human health if concentrations of microplastic in drinking water continue to rise.

• The authors cite the problem of classifying microplastics as they come from a multitude of different materials and sizes.

• They can also be combined with numerous different chemicals -for example flame retardants - depending on their original purpose.

• Plastic fragments and fibres from synthetic fabrics were the most commonly found microplastics found in drinking water, the report found.

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Microplastics that can be absorbed into the body found in UK tap water – (Sky News – 22/08/19)

• The World Health Organisation has called for urgent research on the risks of microplastic to human health after confirming that tiny fragments are found in drinking water.

• In its first assessment of plastic pollution the WHO concluded that there was evidence from 50 studies that microscopic particles are found in water and could be absorbed by the human body.

• Professor Peter Jarvis of Cranfield University, one of the report's authors, told Sky News that tap water in the UK contains between zero and 10 microplastic pieces in every litre, but bottled water can contain "a few hundred".

• "Where there is opportunity for water to interact with plastic material there is opportunity for plastic to go into the water source," he said.

• "There are higher risks of exposure to plastics from bottled water than tap water. The evidence points to the cap itself as the main contributor to plastics in the water."

• The WHO report says particles too small to be seen with the naked eye are likely to be absorbed by the human body but "firm conclusions" on the risk "cannot yet be determined".

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SAPEA’s Evidence Review Report on micro- and nano-plastic pollution, published in January 2019

“The best available evidence suggests that microplastics and nanoplastics do not pose a widespread risk to humans, or the environment except in small pockets. But that evidence is limited, and the situation could change if pollution continues at the current rate.

Supports the views expressed in the WHO report

Movement of plastic from economic activity into the environment SAPEA, 2019: A scientific perspective on microplastics in nature and society

666

Occurrence and removal of microplastics in an advanced drinking water treatment plant (ADWTP)Science of The Total Environment - 15 January 2020, Volume 700, ZhifengWangabTaoLinabWeiChenab

• The number of 1–5 μm MPs in the effluent of ozonation tank was increased by 2.8–16.0%, resulting in a negative removal efficiency in ozonation.

• The removals of microplastics were depended primarily on their physical properties (size and shape).

• Microplastics (MPs) have attracted worldwide attention as the emerging persistent pollutants. Since they have been detected in raw water and the treated water of drinking water treatment plants (DWTPs), there was an urgent need to explore the properties and fates of microplastics in DWTPs.

• The characteristics of the effluent MPs from each treatment unit in an advanced drinking water treatment plant (ADWTP) were studied, and the relationship between the variations of MPs and the removal performances of treatment processes was also explored.

• Overall, both the coagulation combined with sedimentation and the granular activated carbon (GAC) filtration performed well in removing microplastics. The former had a removal efficiency of about 40.5–54.5%, mainly for fibres' removal, and the presence of GAC filtration reduced the microplastic abundance by about 56.8–60.9%, mainly for small-sized MPs.

777

Drinking water and micro-plastics report –Tougher action is needed to stop micro-plastic pollution entering

our waterways. 09 Sep 2019:- Friends of the Earth.

• A new report by the water industry published today (Monday 9 September 2019) has revealed that water treatment processes remove 99.9% of micro-plastic particles from sources of drinking water.

• Earlier this year Friends of the Earth and Bangor University found micro-plastic pollution in all ten of the lakes, rivers and reservoirs they tested across Britain.

• Friends of the Earth’s plastics campaigner Julian Kirby said: “While it’s clearly good news that most micro-plastics are removed from our drinking water, it’s disturbing that micro-plastic pollution in our environment is so widespread.

• “Action must also be taken to prevent pollution from micro-plastics contained in sewage sludge from wastewater treatment works. 80% of this is spread on farmland -meaning huge quantities of micro-plastic are deposited into our environment.

• “The fact plastic is present in our waters suggests we need to consider micro-plastic pollution as an emergent contaminant in any future water quality assessments.

• “But ultimate responsibility for stemming the tide of plastic pollution lies upstream, with the producers of potentially polluting plastic. Focus must be on plastic reduction and the government must legislate to make this happen.”

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Occurrence of microplastics in raw and treated drinking waterMartinPivokonskyaLenkaCermakovaabKaterinaNovotnaacPetraPeeraTomasCajthamlbVaclavJandac

Science of The Total Environment; Volume 643, 1 December 2018, Pages 1644-1651

The study investigates the content of microplastic particles in freshwater and drinking water. Specifically, three water treatment plants (WTPs) supplied by different kinds of water bodies were selected and their raw and treated water was analysed for microplastics (MPs).

• Microplastics were found in all water samples and their average abundance ranged from 1473 ± 34 to 3605 ± 497 particles L−1 in raw water and from 338 ± 76 to 628 ± 28 particles L−1 in treated water, depending on the WTP.

• This study is one of very few that determine microplastics down to the size of 1 μm, while MPs smaller than 10 μm were the most plentiful in both raw and treated water samples, accounting for up to 95%.

• Despite 12 different materials forming the microplastics being identified, the majority of the MPs (>70%) comprised of PET (polyethylene terephthalate), PP (polypropylene) and PE (polyethylene).

• This study contributes to fill the knowledge gap in the field of emerging microplastic pollution of drinking water and water sources, which is of concern due to the potential exposure of microplastics to humans.

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Microplastics in drinking water treatment –Current knowledge and research needsScience of The Total Environment - Volume 667, 1 June 2019, Pages 730-740

KaterinaNovotnaabLenkaCermakovaacLenkaPivokonskaaTomasCajthamlcdMartinPivokonsky

Drinking water treatment plants (DWTPs) pose a barrier for MPs to enter drinking water; thus, the fate of MPs at DWTPs is of great interest. This review includes a summary of the available information on MPs in drinking water sources and in potable water, discusses the current knowledge on MP removal by different water treatment processes, and identifies the research needs regarding MP removal by DWTP technologies.

• Microplastics (MPs) are being detected in freshwaters and also in drinking water.

• Drinking water treatment plants pose a barrier for MPs to enter drinking water.

• Conventional treatment processes have a potential to remove a part of microplastics.

• Efficiency of distinct treatment steps versus MPs character should be understood.

• Regarding water treatment, special focus should be put on small-sized MPs (< 10 μm).

• Although the potential toxicological effects of MPs are still largely unknown, their presence in water intended for human consumption deserves attention.

• A comparison of MPs with other common pollution agents is also provided. We concluded that special attention should be given to small-size MPs (in the range of several micrometres) and that the relationship between MP character and behaviour during distinct treatment processes should be explored.

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About UK Water Industry Research

• Not For Profit organisation set up in 1993 by UK water companies

• Funded and wholly owned by its 20 current members

• Common interest research themes

• Annual subscription revenue for research £2,500,000+

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UKWIR community:

Role Numbers & Comments

Board 1 Executive Director – CEO; 16 Non Exec Directors -1 for each WASC, 3 representatives for WoCs , IW

Staff 5 full time staff, 1 part time

Programme Leads 10 – experts in key research themes, all employees of members

Project Managers 15 to 25 – all part-time contractors

Project Steering Groups Made up of technical experts - over 150 employeesof members, government and regulators take part

Company Research Managers

20 member employees - one for each member

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Our aims:

1. To be the ‘go to’ place for water industry research

2. To shape the future water research agenda for members, in partnership with government, regulators & other stakeholders

3. To provide an efficient, effective and flexible research delivery process

4. To deliver research that makes a difference and enables innovation

5. To set the highest standard for learning and governance

6. Independent, high quality sound science research

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• Core programme:

➢ Projects suggested by the membership➢ Voted on and agreed by the membership➢ Mostly tactical and shorter term research➢ Currently ~85% of budget

• Strategic programme:

➢ Long term challenges facing the industry➢ Projects agreed by the membership & wider industry community➢ All strategic projects➢ Will increase to ~70% of budget over time

Research Programme:

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Sink to River – River to Tap A review of potential risks from nanoparticles and microplastics - May 2019 - EQ01A231

The primary objective of this study was to inform the UK water industry on the levels of microplastics present in the water, wastewater and sludge handled by their treatment works.

In order to achieve this goal the project:-

• developed a robust sampling and detection methodology to allow the quantification of microplastics at a range of different points within the water environment and the water industry’s infrastructure. Prior to this project, it should be noted that no standardised methods or reference materials were available.

• Ensured a representative overview - samples were taken from eight water treatment works (WTW) and eight wastewater treatment works (WwTW) from different companies across Great Britain. For water, the samples included raw water, potable water, and waste sludge from WTWs. From wastewater, samples of influent, effluent and sludge cake were collected from WwTWs. The sites were chosen to represent the processes widely used in combination in the UK and elsewhere.

• Used these cutting-edge analytical methods, to provide accurate results, and provide a sound foundation on which to develop further research. The project devoted significant effort to understand, quantify and correct for microplastic contamination to ensure confidence in the results.

MICROPLASTICS:- MONITORING TECHNIQUES TO IDENTIFY MATERIAL ENTERING AND LEAVING WATER TREATMENT WORKS

Andrew Johnson, Alice Horton, Dan Read

Monika Jürgens, Richard Cross, Elma Lahive, Hollie Ball,

Claus Svendsen

Part of an UKWIR funded project looking at “microplastics source to tap, sink to river” - 2019

THE WORLD APPETITE FOR PLASTIC CONTINUES TO GROW

Maphoto/Riccardo Pravettoni (http://www.grida.no/ resources/6923).

THE WORLD APPETITE FOR PLASTIC CONTINUES TO GROW

PLASTICS AND SOCIETY

MICROPLASTICS IN THE WATER CYCLE

• Widespread pollution of coastal sites by tiny fragments of plastic first reported in 2004

• A significant proportion of the 300 million tons of plastics produced each year in the world are lost to the environment

• Degradation is extraordinarily slow• Microplastics generally assumed to be

between 5 mm and 100 nm.• They are difficult to quantify across all the

size ranges and polymers• Due to quantification issues, much of the

literature is biased towards quantifying large brightly coloured particles!

SOURCES AND SINKS OF MICROPLASTICS IN THE

ENVIRONMENT

Ref:9789241516198 - WHO Microplastics-2019

WHAT IS THE LITERATURE TELLING US ABOUT

MICROPLASTICS IN CLEAN WATER?

861

0.0007

141

0.0007

2.5

16,939,064

4,889

0.00010.0010.010.1

110

1001000

10000100000

100000010000000

100000000

Rawwatermean

Rawwater

median

Potablewatermean

Potablewater

median

Tapwatermean

Bottledwatermean

Bottledwater

median

Microplastics in clean water per litre

It depends who you ask and their methodology!

Mic

rop

last

ic p

arti

cle

s/L

(lo

g sc

ale

)

WHY IS THERE SO LITTLE CONSISTENCY IN MICROPLASTIC MEASUREMENTS?

• Difficult to enumerate particles

• People are reporting on different size ranges

• Optical selection methods subject to bias

• Possible quality control issues, lab contamination is a very real danger!

Samples collected in recent UKWIR project

Three types of samples:

Raw Water

Potable WaterSludge (WTW)

DEFINITION OF MICROPLASTICS USED IN THE UKWIR PROJECT

• Material that can be captured on a 10 µm filter

• That is of 25 µm size or larger (pixel size selected for FTIR)

• That is one of nine common polymers ascribed to a better than 0.6 probability

• Accepting that the FTIR does not separately identify long and narrow microfibres (unlike the human eye)

THE MICROPLASTIC POLYMERS LOOKED FOR IN

THE UKWIR PROJECT

• ABS – acrylonitrile butadiene styrene (e.g. car bumpers, pipes, Lego© bricks)

• PA – polyamide (e.g. nylons in textiles, clothing and cars)

• PE – polyethylene (e.g. plastic bags)

• PET – polyethylene terephthalate (e.g. plastic bottles and ‘polyester’ in clothing)

• PMMA – poly(methyl methacrylate) (e.g. as Perspex a glass substitute)

• PP – polypropylene (e.g. as pipes, containers)

• PS – polystyrene (e.g. as bottles, trays, tumblers, disposable cutlery)

• PVC – polyvinylchloride (e.g. cables, pipes, double glazing frames, flooring)

• PU – polyurethane (e.g. insulation foam, seals and skateboard wheels)

These polymers expected to dominate if clothing is the main source

SAMPLING RAW AND POTABLE WATER

check valve with isolator

Filter holder with 10µm stainless steel cartridge filter

valve

Waste pipe

Water meter

Non-return valve

Filter holder with 10µm stainless steel disc filter

valve

Different filter holdersfor raw or potable watersampling

We must minimise materials which shed plastic!

The materials must be acceptable for a drinking water plant

SAMPLING STRATEGY FOR MICROPLASTICS IN WATER

Sample type Sample size Number samples Approach

WTW Raw water 1-2 m3* 6 sites x 5 Directly from tap (collaboration with Utility)

WTW Potable water

1-6 m3* 8 sites x 5 Directly from tap (collaboration with Utility)

WTW sludge 250 g or 1L 2 sites x 5 Final product (collaboration with Utility)

* Normally collected overnight

The great mercy of working with microplastics is…. - Microplastics are not likely to degrade following sampling, transport and storage

Devising a suitable processing

protocol. There are many micro-

particles - but not all are plastic!

• Many organic and inorganic particles will be trapped…. and they absorb infrared light too!

• You need to eliminate these interfering particles…..

• But not eliminate your plastic at the same time!

• Find a method which is a balance between successful elimination of non-plastics but which does not consume too much time or expense, i.e. ‘good enough’

2. Pour the sample between two beakers 6x until mixed

to take the subsample

1. Sonicate the filter to dislodge all particles into suspension in ultrapure

water

S1 S2

Step 1 Step 2Transfer of the unprocessed sample for dispersion and sub-sampling for subsequent storage or processing.

Filters from the field sampler

POTABLE

S2 Processed for analysis

S1 Stored in ethanol

1) The 10 mm filter is removed from (potable) rig…

RAW

Potable water Raw water

1. Transfer to suspension and subsampling

1. Transfer to suspension and subsampling

2. Fenton’s Reaction

2. Enzyme Digestion 3. Enzyme Digestion

3. Dispersion in ethanol for storage and analysis

4. Dispersion in ethanol for storage and analysis

Potable water protocol Raw water protocol

1. Fenton’s digested sludge suspended in ZnCl2

(1.7 g cm-3)

2. Flotation for 24 hours to sediment excess organic

and inorganic matter >1.7 g cm-3 in density

3. Sedimented material released through tap,

leaving the supernatant containing microplastics

Step 1: Fenton’s reaction to degrade natural organic matter and break apart the dry sludge sample

Step 3: Enzyme Digestion

The separation and processing of sludge

Step 4: Step 4: Separation into coarse (>200 µm) and fine (<200 µm) fractions for FTIR

Step 2: Flotation separation

One gram dry mass of sludge processed per sample.

Fourier transform infrared spectroscopy (FTIR)

FTIR shines an infra-red beam containing many frequencies of light at once and measures attenuated internal reflectance which is different for each polymer

Perkin ElmerSpotlight 400 IR

Blank FTIR absorption Blank (8 polyethylene MPs)

What the FTIR sees and then interrogates for one polymer(actually this was a blank sample)

Blank_raw_10um_311018

Example of the 12 x 12 mm disc examined by FTIR and then image analysis by MP-Hunter software

MP-Hunter converts each particle it seesinto the most probable material. Separately, itestimates the dimensions

The MP-hunter software then interprets the FTIR output and generates results for each of our nine target polymers

The whole processtakes 2.5 h to scan and a further0.5 h to analyse.

Each samplegenerates an700 MB file

BLANK CORRECTION, LOD AND LOQ

• For blank samples, all the preparation steps were the same as for the potable protocol, 10 repeats (enzymic) or raw water, 8 repeats (enzymic plus Fenton’s). Sludge blanks simply ran the sludge protocol for 5 repeats

• The LOD was taken to be the mean blank + SD*3.3 and the LOQ to be the mean blank + SD*10 as recommended by AOAC

How does this work?

• The mean blank value is subtracted from sample count

• Only if the corrected value exceeded the LOD could it be said to be detected

• Only if the corrected value exceeded the LOQ could it be said to be quantified

1.5

3.3

20

65

1.1

20

1.1

1.1

1.14.6

10

60

197

3.3

60

3.3

3.3

3.3

0

50

100

150

200

250

ABS PA PE PET PMMA PP PS PVC-U PU

MP

in the w

hole

pro

cessed

(sub-)

sam

ple

LOD (3.3 * SD of blank, or 1 particle in the 92% analysed filter area, if…

RESULTS FROM POTABLE WATER BLANKS (10 REPS) FOR EACH

POLYMER

0

10

20

30

40

50

60

70

MP

in the w

hole

pro

cessed (

sub-

)sam

ple

Mean30/10/201808/01/201915/01/201921/01/201928/01/201912/02/201918/02/201925/02/201928/02/201911/03/2019

Raw microplastic counts

Converted to LOD and LOQs

Note how PE,PET and PP aremost commoncontaminants inthe laboratory!

QUALITY ASSURANCE: HOW WOULD THIS APPROACH

SCORE COMPARED TO OTHERS IN THE FIELD?

Inclusion and reporting Score

Sampling site, date and materials used fullydescribed

2

Adequate sample size taken 2

Container cleaning reported 2

Precautions to avoid Lab contamination given 2

Clean air conditions used 2

Negative controls used (blank correction) 2

Positive controls used (spike recovery) 1

Processing/digestion step reported 2

Polymer ID 2

Total score 17

Of 56 papers in the general field of surface water and drinking water, the highest aggregate score using this method was 15. The majority of studies scored only 10 or less

The Koelmans et al (2019) scoring system

This project would meet almost all the required criteria and would score higher than previous studies!

THE RANGE OF WTWS SAMPLED

Code Description Treatment

WTW 1Lowland river, direct abstraction

GAC, membrane, UV/H2O2, GAC, disinfection

WTW 2Lowland river, direct abstraction

HBC, RGF, GAC, disinfection

WTW 3Lowland river, direct abstraction

Disinfection, pH balancing, static mixer, clarifier with FeCl3 & polyelectolyte coagulation, RGF, GAC, microscreen

WTW 4 Lowland river, pumped storage DAF or HBC, RGF, GAC, disinfection

WTW 5 Lowland river, pumped storageReservoir with SSF, RGF, ozone, SSF, disinfection

WTW 6 Groundwater, chalk Disinfection

WTW 7 Groundwater, greensandAeration and pressure, filtration, disinfection

WTW 8 Pristine upland reservoirAl2(SO4)3 coagulation. RGF, disinfection, pH balancing, UV

QUANTIFIED MICROPLASTICS IN THE RAW WATER

SOURCES OF THE DIFFERENT WTWS

Presence of microplastics not routine, but PE was the most common polymer quantified in raw water

Mic

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last

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arti

cles

/L

0

20

40

60

80

100

120

1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5

WTW 1 WTW 2 WTW 3 WTW 4 WTW 5 WTW 8

WTW raw water microplastics/L, only values >LOQ

ABS PA PE PET PMMA PP PS PVC-U PU

QUANTIFIED MICROPLASTICS IN POTABLE

WATER AT THE WTWS

Microplastics are rarely quantified but this time it is ABS and PS polymers found

Mic

rop

last

ic p

arti

cles

/L

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

1 2 3 4 5 1 2 3 4 5 1 2 3 4 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5

WTW 1 WTW 2 WTW 3 WTW 4 WTW 5 WTW 6 WTW 7 WTW 8

WTW potable water microplastics/L, only values >LOQ

ABS PA PE PET PMMA PP PS PVC-U PU

DETECTED BUT NOT QUANTIFIED MICROPLASTICS IN

POTABLE WATER AT THE WTWS

Wide range of microplastic polymers can be detected but too low for quantification

Tentative numbers

0

0.005

0.01

0.015

0.02

0.025

0.03

1 2 3 4 5 1 2 3 4 5 1 2 3 4 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5

WTW 1 WTW 2 WTW 3 WTW 4 WTW 5 WTW 6 WTW 7 WTW 8

WTW potable water microplastic particles/L, only values >LOD

ABS PA PE PET PMMA PP PS PVC-U PU

OVERALL PERFORMANCE OF THE 8 WTWS FROM ALL

SAMPLES (ONLY USING VALUES ABOVE THE LOQ)

Overall 99.99% removal

4.9 0.00011

0.00001

0.0001

0.001

0.01

0.1

1

10

WTW raw Potable

n=7/30 n=2/39

Mic

rop

last

ic p

arti

cles

/L

Average and standard deviation of all WTW samples in microplastics/L

POSITIVE DETECTIONS OF MICROPLASTIC

POLYMERS IN WTW SLUDGE

PE and PP the dominant forms found

Mic

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last

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arti

cles

/g D

W

WTW 2 WTW 3 WTW 4 WTW 8 WTW 3

WTW 3 only

OVERVIEW OF SIZE DISTRIBUTION FOR OUR DIFFERENT

SAMPLE TYPES

• Size profile of contaminants in blanks was similar to field samples

• Indicating that the smaller you go, the more you will find!

• Suggests there are a large number of unquantified microplastics <25 µm

LIMITATIONS OF THE STUDY

• This study was only reporting on microplastics of 25 µm and above

• Laboratory contamination by microplastics is routine. A thorough blank correction process was essential (but rare in the literature)

• The topic of spike recovery needs further efforts, not a trivial issue

• Current processing still does not eliminate all IR-interfering materials

CONCLUSIONS – DRINKING WATER SIDE

• Microplastics are rarely found above the LOD or LOQ in potable water

• In 39 visits only three values were above LOQ (highest 0.002 microplastics/L)

• The most common plastic polymers found in potable water were PS and ABS

• Microplastics in raw water could be present at relatively high levels for WTWs using direct pumped river water

• Overall the WTWs remove 99.99% of microplastics. This was reflected in the relatively high numbers of microplastics found in WTW sludge

CONCLUSIONS FOR DRINKING WATER

• Microplastics are rarely found above the LOD or LOQ in potable water in the WTWs studied

• In 39 visits, only three values were above LOQ (highest 0.002 microplastics/L)

• The most common plastic polymers found in potable water in these WTWs were PS and ABS

• Did not find as much of the ‘clothing polymers’ , PA and PET as expected

• Microplastics in raw water could be present at relatively high levels for WTWs using direct pumped river water

• Overall the WTWs studied remove 99.99% of microplastics. This was reflected in the relatively high numbers of microplastics found in WTW sludge

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Environmental exposure to microplastics: An overview on possible human health effectsScience of The Total Environment; Volume 702, 1 February 2020, 1344-55Joana Correia, PrataaJoão P.da, CostaaIsabel,Lopesb,Armando C.Duartea,T eresaRocha-Santosa

Little is known about the effects of microplastics in human health. This work reviews the evidence for potential negative effects of microplastics in the human body, focusing on pathways of exposure and toxicity.

Microplastic exposure may cause particle toxicity, with oxidative stress, inflammatory lesions and increased uptake or translocation. The inability of the immune system to remove synthetic particles may lead to chronic inflammation and increase risk of neoplasia. Furthermore, microplastics may release their constituents, adsorbed contaminants and pathogenic organisms.

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Identifying the solutions

Following publication of the UKWIR study Michael Roberts, ex-Chief Executive, Water UK said:

• “This important research underlines the effectiveness of water treatment in the UK in removing microplastics and other pollutants from our water supply. It’s thanks to these robust processes that the we all enjoy world class water whenever we turn on our taps.

• “However, while the vast majority of microplastics are removed in the treatment process, we aren’t complacent and therefore will support UKWIR in undertaking further research to understand the true nature and impact of this hidden problem.

• “Action from government, industry and the public remains critical to prevent these microplastics entering our water system and wider environment in the first place. Tackling our over reliance on plastics and improving end of life collection will be the only way to effectively address any risks from such pollutants.”

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REMOVAL OF MICROPLASTICS BY DRINKING WATER TREATMENT PROCESSES (Ref: DWI 70/2/326)

The project is:

• Reviewing existing literature on occurrence of microplastics in water

sources, drinking water, the relative importance of different sources of inputs

to water and removal by drinking water processes.

• Reviewing the methods of analysis that have been used to determine

microplastics in water.

• Summarising existing knowledge on human exposure to microplastics

through food, water and air and any associated risk assessments

• Conducting bench scale experiments to determine the efficiency of removal

of a different sizes and types of microplastics by a range of drinking water

treatment processes.

• Based on the findings of the bench study and other aspects, developing an

approach to monitoring a small number of final waters for microplastics.

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UKWIR Proposal DW1202 - Micro-plastics in Drinking Water

• This project will build on the recently completed project with regard to the removal efficiency of micro-plastics by the range of water treatment unit processes deployed within the Industry.

• Further effort is needed in method development and QA/QC procedures especially in the field of spike recovery also known as ‘positive controls’.

• Developing methodologies to improve the detection of fibres and microplastics <25µm

• Our recent project reported on nine of the most common plastic polymers, we may analyse some of our existing samples for a much larger range of polymers. This would include a need to construct individual LODs and LOQs for these more exotic polymers

• Given the use of plastics in pipes, containers and valves associated with the delivery of potable water from the WTW to the consumer, we will examine whether microplastics are present at downstream locations en-route to customers

• Understand the extent and impacts of airborne deposition of ultra-small microplastics eg with respect to the risk of entry into open water storage reservoirs.

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The Big Questions – UKWIR’s Strategic Research Goals

• Water industry faces increasing challenges in the long term

o Growing population

o Changing climate

o Rising customer expectations

o Market reform

• UKWIR developed 12 Big Questions to tackle these challenges

o Identified through extensive consultation and discussion

o Form strategic research programmes

• UKWIR - Big Question 12 achieve zero impact from plastics via our operations and activities by 2050?

o How do we achieve zero impact from plastics via our operations

and activities by 2050?

https://www.ukwir.org/

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How do we achieve zero impact from plastics via our operations and activities by

2050?

The entry of harmful plastics into our products and water cycle is effectively controlled

at source

We can confidently identify, monitor and report the levels

of harmful plastics through our operations and activities

Our treatment processes can effectively remove harmful

plastics

Any effects of the plastics in our bio-solids are quantified and have no negative

impact on soil health

Our activities remain sustainable, and actively support reducing the impact of plastics in the aquatic

environment

Key themes

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Development of the roadmap

• Oxford University Innovation commissioned to undertake literature review to provide baseline for future discussion of current gaps in evidence and help prioritise future research challenges

o Widely and internationally recognised that microplastics are ubiquitous in water cycle

o However, research is still in early days

o Interpretation of evidence is often unclear

o Often a lack of data, or lack of consensus

o BUT lack of data doesn’t imply lack of risk, just reinforces need for further research

• Carried out interviews with various stakeholders (water industry, academia, regulators)

• Used the outputs from these to inform the content and structure of the road mapping workshop in June

o 38 delegates from water industry, academia and regulators

o Define, develop and prioritise key research challenges

o Four areas focussed on; clean water, waste water, sludge, defining the nature of the problem (sampling, analysis and characterisation)

• Links between different areas, but some perhaps more complex to understand, and general agreement that most questions should be answered by 2030

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Zero harm from plastics via our operations and activities by 2050?Vision

Outcomes

Key Benefits

The entry of harmful plastics into our

products and water cycle is effectively

controlled at source

We can confidently identify, monitor & report the levels of harmful plastics through our

operations & activities

Our treatment processes can effectively remove

harmful plastics

Any effects of the plastics in our biosolids are quantified & have no negative impact

on soil health

Our activities remain sustainable &

actively support reducing the impact

of plastics in the environment

A B C D E

Identifying economical

retrofit options

Removal & transformation

mechanisms across treatment

stages

Optimising existing

processes to maximise plastics

removal

Identifying thresholds of

harm for sludge applied to land

Can the industry use plastics as a

resource

Plastics in CSOs/overflows

Sources and characteristics of plastics at works

inlet

Identify who we should be

engaging with

We have identified how our processes can minimise plastics to the environment

We understand our total plastic load to the soil

We can make more informed

decisions regarding safe

disposal of sludge to land

Current options for controlling

plastics at source

2030

2020

Maximising value of sludges to

support circular economy

Develop a risk based sampling

programme

Identifying the framework and tools to better

control plastics at source

2025

We understand the main

sources of plastics

The volume of plastics we

receive at our works has been

reduced

We know how and where to

sample for plastics

We can reliably monitor plastics

Interactions between micro- &

nano plastics, associated

chemicals with human systems

Define best approach to determine hazard/risk

Mechanisms for transfer between

domains

Develop new predictive impact

models

Identify most significant

plastics within mixtures

Interactions between micro-& nano plastics,

associated chemicals with &

environment

Identify appropriate

sampling methodology

Identify work required to ensure data

comparability

Techniques and automated

technologies to best detect and

characterise micro & nano

plastics

Identify error levels associated

with sampling technologies

Develop technologies to

fill measurement gaps

575757

• This is a dynamic route map and will be modified as projects are completed and better information is known

• Many projects help deliver several outcomes, the linkages are not displayed on this route map

Key

Supporting Information

UKWIR Project

Project relating to harm of plastics that would be required for the water sector, not just the water industry

Project relating to sampling and analysis of plastics that would be required for the water sector, not just the water industry

58

Zero harm from plastics via our operations and activities by 2050?Vision

Outcomes

Key Benefits

The entry of harmful plastics into our

products and water cycle is effectively

controlled at source

We can confidently identify, monitor & report the levels of harmful plastics through our

operations & activities

Our treatment processes can effectively remove

harmful plastics

Any effects of the plastics in our biosolids are quantified & have no negative impact

on soil health

Our activities remain sustainable & actively support reducing the impact of plastics in

the environment

A B C D E

Identifying economical

retrofit options

Removal & transformation

mechanisms across treatment

stages

Optimising existing

processes to maximise plastics

removal

Identifying thresholds of

harm for sludge applied to land

Can the industry use plastics as a

resource

Plastics in CSOs/overflows

Sources and characteristics of plastics at works

inlet

Identify who we should be

engaging with

We have identified how our processes can minimise plastics to the environment

We understand our total plastic load to the soil

We can make more informed

decisions regarding safe

disposal of sludge to land

Current options for controlling

plastics at source

2030

2020

See next page

Maximising value of sludges to

support circular economy

Develop a risk based sampling

programmeIdentifying the framework and tools to better

control plastics at source

Identify what are harmful

plastics – human & ecotoxicology

Standard methods for sampling &

analysis - micro & nano plastics

2025

We understand the main

sources of plastics

The volume of plastics we

receive at our works has been

reduced

We know how and where to

sample for plastics

We can reliably monitor plastics

59

Zero harm from plastics via our operations and activities by 2050?Vision

Outcomes

Key Benefits

We know what harmful plastics are

We have quantitative methods to sample and measure micro- & nano

plastics

Interactions between micro-& nano plastics,

associated chemicals with human systems

Define best approach to determine hazard/risk

Mechanisms for transfer between

domains

Develop new predictive impact

models

Identify most significant

plastics within mixtures

Identify appropriate

sampling methodology

We can measure and

compare micro & nano plastics quantitatively

Identify work required to ensure data

comparability

Techniques and automated

technologies to best detect and

characterise micro & nano

plastics

Identify error levels associated

with sampling technologies

Develop technologies to

fill measurement gaps

Interactions between micro-& nano plastics,

associated chemicals with & environment

We understand which plastics cause harm &

need to be removed

This work is vital to allow the water industry to understand the implications of plastics –identifying what is harmful and how to determine the concentrations/ load

However, it represents work that would be required for the water sector, not just the water industry

2030

2020

2025

606060

Current progress/future steps

• UKWIR ‘Sink to river, river to tap’ project completed

o Recommended further developing methods

o Found 99.99% removal of microplastics in drinking water and 99.9% removal in wastewater

o However, recognise there is still more to be done!

• 2 PhDs still underway (Plymouth & Exeter Universities)

o Plymouth - Quantifying the influence of waste water treatment on the release of microplastic to the environment

o Exeter - Characterisation of microplastics found in wastewater and sewage sludge

• CIP3 also includes microplastics monitoring (wastewater & sludge)

o Each company will have 1 sewage sampled 4 times over the year, at various process stages, influent, effluent and sludge. Contractor TBC, final report due September 2021

• No new project suggestions received in current cycle of suggestions

• Need to agree next research steps and who should/can deliver this

• Need to understand links to other research areas, i.e. NERC grant areas, Water UK Public Interest Commitment, Defra/EA research

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Questions and table groups