19.9.2016

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Contaminated soil

– focus on groundwater pollution

Jaana Sorvari

Contaminated soil: how you define it ?

Very generally:

Soil that has harmful chemicals in it

Regulatory perspective:

e.g. UK: Causes significant

• harm to people or protected species

• pollution of surface waters or groundwater

In Finland also:

• can cause impairment of site’s amenity

• can otherwise violate the private or public

interest”

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→ determined by hazards or RISKS, NOT directly by concentrations

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Diffuse & point sources

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Point sources, Europe

?

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About groundwater

Facts, global scale

• GW represents over 90% of

world’s readily available

freshwater

• Drinking water source for ca.

1,5 bil. people

• Ca. 600-700 km3 extracted /

year ≈ 20% of global water

withdrawals

Groundwater areas in Europe

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Facts & threats, Europe

• Supplies ca. 65% of drinking water

• 60% of cities overexploit their resources

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Department of Built Environment

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Finnish perspective

Almost 24 000 registered,

potentially contaminated sites

• 4 350 (18 %) is in classified GW areas

• Of the 4 350, > 83 % is in I class GW area

• > 500 sites < 100 m from a classifiedGW area

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Case: The story of Kärkölä, Finland

How everything started…the source

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A sawmill area of Koskisen Ltd.

• in operation since 1931

Chemicals

• from 1940’s till 1984 wood

preservation using KY5 chemical

Environment

• groundwater area class I, nearest

waterworks serves 3500 inhabitants

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What is KY5 ?

Effective ingredients

• chlorinated phenols (CP)

• also polychlorinated dioxins (PCDD) and

furans (PCDF) as impurities

CPs

• easily soluble in water

• highly toxic to aquatic organisms

• manifestations in humans: in liver, kidneys,

skin, gastric system, immune system; cancer

• can transform to more toxic compounds (e.g.

PCDDs+PCDFs)

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Department of Built Environment

What happened ?

A fire in May 1976

→ Sawmill plant and chemical

storage partly destroyed

→ → KY5 with CPs emitted to

the environment, exact volume

unknown*

Also (?): careless handling of

KY5 overflow of KY5 pool

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Migration to groundwater*3300 kg according to later estimates

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Consequences

Groundwater

• in 1987: CP in waterworks > 10 x quality standard for standard for household water (10 ug/l)

→ waterworks closed 12/1987

• later: outside waterworks CP 56 000-190 000 µg/l

Edible fish, lake Valkjärvi

• CP in fish > 7000* µg/kg (max, much higher in liver)

Humans

• elevated concentrations of CP in urea, particularly persons eating fishfrom adjoining lake Valkjärvi

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*EU’s generic default limit value (MRL) for PCP in food 10 µg/kg

Department of Built Environment

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Different stakeholders, different reactions

Municipal manager:

”breathing the air in Helsinki or passive smoking is more risky

than eating the fish from Valkjärvi”

”health risks from eating the fish from Valkjärvi are insignificant”

”media has excaggerated the health risks”

Minister of the Environment:

”worst case ever”

Residents:

”information has been concealed”

CEO of Koskisen Oy

”minister should resign”

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Signs in human beings

• Several symptoms, e.g.

gastrointestinal and dermal

manifestations, respiratory

infections; dose-response

correlation confirmed

• Cancers in 1972-1986:

excess of soft-tissue sarcomas

and non-Hodgkin’s lymphomas

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Department of Built Environment

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Scene 1: The long arm of the law gets a grasp ?

The CEO charged for polluting the groundwater and

claims presented to the court…

BUT

the Water Rights Court dismissed the claims since:

”no connection between the contamination of water in

the water plant and working methods used in the

sawmill has been demonstrated”

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Next step - the Water Rights Appeal Court…

…keeps the previous decision but states (05/1993) that

• based on the studies on lake sediments, CPs have entered to soiland GW also before the fire

• there are no other probable sources of CPs

• the defendant was responsible for preventing GW contamination

HOWEVER

• ”No such information was available by the time of the use of KY5 that would let one to assume that when present in soil it poses a risk to groundwater; particularly when alsoconsidering soil type (clay) and direction of surface water flow”

= no indifference shown in handling KY5 and

= it was not predictable that handling KY5 could contaminate

GW in waterworks (distance 800 m)

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The media is interested…

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…and so are researchers

Studies on

• population health

• contamination of lake Valkjärvi

• geological conditions

• transport of CPs in groundwater

(modeling)

• GW remediation methods

• …

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And the lawyers profit…

Various appeals, statements, decisions,

and an administrative compulsion

Various issues

• Time of the accident (fire) vs. date when the

Waste Management Law came into force

(01/04/1979)

• Regional authority’s decision on the

environmental permit application

• Non-intention: many studies imply that high CP

concentrations not related to the normal activities

and use of KY5

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Closing the case

Supreme Administrative Court’s decision

10/2008

• Koskisen Ltd is responsible for groundwatercontamination

• No remediation targets defined, however

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Remediation attempts

Ex situ: Treatment in municipal waste water

plant (activated sludge) 1989-1992

• ca. 50 kg CP removed

• would take ca. 90 years

On site: Pump & treat

activated carbon 12/1993-1997

• ca. 360 kg CP removed

• too expensive

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Remediationattempts

On site: Pump & treat

bioreactor 1/1995-1999

- Based on bacteria

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Results from the bioreactor treatment

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CP concentration µg/l

CP reduction

87 – 98 %, ca.

760 kg CP

removed

In 1999

operation

disturbed

Only 10-15%

of GW formed

daily cleaned

Input

Output

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Final solution – ”underground bioreactor”Remediation plan accepted 02/2012

New in situ remediation started 25/06/2012

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Absorption

well Abstraction

well

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Results from the in situ ”bioreactor”

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CP reduction 91 - 92 %

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Months from the start

To

tal c

on

ce

ntr

ati

on

µg

/l

Recharge GW

CP concentration

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Future of Kärkölä groundwater

Good status (as defined in the

legislation) can most probably be

attained by 2027

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Concluding remarks

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Your lessons learned ?

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Challenges to ground water riskassessment and remediation

• Hydrogeological conditions

• Soil heterogeneity: prediction of contaminant transport

from unsaturated zone to saturated zone

• Transport in fractured bedrock

• Degradation (organic pollutants): effect of environmental

conditions

• Non-aqueous phase liquids (NAPL)

• Multiple contaminants

• …

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Department of Built Environment

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