| Slide 1 Establishing Threshold Values for Groundwater Johannes Grath Andreas Scheidleder 26 June 2007.

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Establishing Threshold Values for Groundwater

Johannes Grath

Andreas Scheidleder

26 June 2007

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Contents

GWB Delineation

GWB characterisation

Risk assessment and Threshold values

References

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GWB Delineation

GWB characterisation

Risk assessment and Threshold values

References

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WFD - Definitions

Definitions in WFD Article 2

‘Groundwater’ means all water, which is below the surface of the ground in the saturated zone and in direct contact with the ground or subsoil.

‘Aquifer’ means a subsurface layer or layers of rock or other geological strata of sufficient porosity and permeability to allow either a significant flow of groundwater or the abstraction of significant quantities of groundwater.

‘Body of groundwater’ means a distinct volume of groundwater within an aquifer or aquifers= managing unit

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WFD – Groundwater body

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GWB Delineation

GWB characterisation

Risk assessment and Threshold values

References

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GWB characterisation & risk assessment

WFD Article 5

1. “…for each river basin district…: an analysis of its characteristic a review of the impact of human activity on the status

of ...groundwater

… according to the Annex II …

… completed 22 December 2004 …”

2. “… review/update 2013…and every 6 years thereafter.”

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all Groundwater Bodies

… analysis … shall identify location and boundaries of GW-bodies pressures

diffuse + point sources of pollution abstraction + artificial recharge

general character of overlying strata directly dependent surface water- or terrestrial

ecosystems

Annex II – Initial Characterisation

CharacterisationRequirements in the WFD

Basis for Risk Assessment

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Groundwater Bodies at risk – (Annex II, 2.2, 2.3) Transboundary Groundwater Bodies – (Annex II, 2.3)

2.2: …where relevant, information on e. g.: Geological characteristics, units….. Hydrogeological characteristics, conductivity, …. …

2.3: … where relevant Points for abstraction Abstraction rate, …

Annex II – Further Characterisation

CharacterisationRequirements in the WFD

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The Conceptual Model

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GWB Delineation

GWB characterisation

Risk assessment and Threshold values

References

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Background

Current activity of WG C Groundwater – Subgroup « Status compliance and Trends »

Mandate: TV paper Article 3 of the GWD (« criteria for assessing groundwater chemical status ») Based on BRIDGE outcomes

Environmental objectives of the GWD / Receptors to protect Articles 3 and 4 (status assessment)

Surface water

Groundwater Depending Terrestrial Ecosystems (GWDTE)

Human uses

Article 5 (trends) Groundwater « itself » 

(Surface water, GWDTE, Human uses)

Article 6 (prevent or limit) Groundwater « itself » 

(Surface water, GWDTE, Human uses)

Full protection of groundwater

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Background

Legal background: GWD (2006/118/EC)Main objectives and requirements

– Groundwater Quality Standards (GW-QS)– Threshold values (TV) for:

• Parameters causing a risk of failing 2015 objectives• Including NO3 and/or pesticides if relevant• Taking the minimum list into account

The links between Article 3 and Article 6

Article 3 Article 6

Large scale (Groundwater Body - GWB) Local scale (groundwater)

Apply to the whole GWB (‘threshold values’) Apply to different ‘Point Of Compliance’(POC)

(‘limit values’)

Criteria:

Surface water, GWDTE, human uses, saline or other intrusions

Criteria:

Surface water, GWDTE, human uses (including future uses), saline or other intrusions, material

property, amenities

Source: A. Blum; WG C meeting Berlin 07

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Background

Required scale for deriving TV 3 possible levels (article 3.2)

National, River district, GWB

Consequence: GWB = the smallest allowed scale for the TV to be reported in the management plan

GWB heterogeneity will have to be taken into account through intermediate values ( « criteria’s values ») and through the appropriate investigation

Schedule and revision Key dates (Article 3.5)

TV to be established by 22 December 2008 TV to be published in the RBMP by 22 December 2009

Revision (Article 3.6)

Information to be reported in the RBMPTransboundary GWB

Source: A. Blum; WG C meeting Berlin 07

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Identification of receptors

GW associated surface waters Rivers, Lakes Transitional, Coastal waters

GW-dependent terrestrial ecosystems and wetlands / mire / GW-fed fens

Human uses (drinking water, irrigation, industrial use, farming, …)

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Identify risk parameters for each receptor

Risk assessment as a basis Surveillance monitoring provides a validation of risk

assessment for rivers, lakes, and groundwater, coastal and transitional water, mires and identifies the parameters responsible for the risks.

Consider As – Cd – Pb – Hg – NH4 – Cl – SO4 – Trichloroetylene – Tetrachloroethylene – Electrical Conductivity (indicator) and determine if there is a risk or not. If yes, then these parameters need a threshold value

Other relevant Parameters?

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Reference (criteria values)

For depending surface waters (rivers and lakes) it is possible to use environmental quality standards for priority substances (draft directive EQS [COM(2006) 397 final] if no appropriate national EQS are available.

For mires it is possible to use local expert knowledge or to apply the EQS for aquatic ecosystems as well.

For drinking water, use the Drinking Water Standards (DWS). If treatment is already used: Use operational performance limit for existing or regionally usual treatment infrastructure.

For other legitimate uses: Dependent on use - Food-related use DWS, for non-food use suggest process operational needs determined on case-by-case

For saline and other intrusion: use the natural background values

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GW-contribution for the risk

Identification of connections (extent of interaction) – discharge/transfer of pollutants to the receptor

Analysis of hydrographs in water discharge monitoring stations - T°C – age of water (tritium), etc.

Use the existing experimental set up along the main rivers of Latvia to derive some values for groundwater contribution to surface water discharge

Expert knowledge on mires: phyto-sociology can provide some information on the groundwater contribution to the wetland

Calculate the amount of pollutants to be transferred from the groundwater to the receptor by considering dilution, attenuation effects to the receptor if available but also seasonal variations

Derive the maximum concentration allowed in the groundwater

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Natural Background level

Derive background levels for all groundwater bodies (shallow and deep groundwater) If there is geochemical data available, separate

pristine data from human influenced data. It is possible to use the BRIDGE methodology or a national methodology

If no geochemical data are available, then use the BIDGE aquifer typology – www.wfd-bridge.net to transfer background values from similar aquifer types in Europe to Latvian aquifers

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Threshold Value

Compare the maximum concentration allowed to the background level

Then this is a political decision If the background value is below the maximum concentration,

then the threshold value can be the maximum concentration allowed (current state of draft guidance paper => “minimum approach”) i.e. it is at the discretion of MS to set lower concentration levels (more strict)

If the background level is above the maximum concentration, Either use background level as threshold value, which means no additional

human pressure Or use a threshold value above the background level to allow human

pressure to some extent. Yet, this implies to reduce the contribution of other polluters to the receptor.

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4. Methodology to derive TV

4.1 Preliminary steps

What are the relevant criteria for the status assessment?

- Surface water and associated terrestrial ecosystems- Legitimate uses

What are the parameters for qualifying a water body’s chemical status?

All pollutants that characterise groundwater bodies as being at risk of not meeting WFD environmental

objectives

Assessing the natural background level of each of the relevant parameter

Source: A. Blum; WG C meeting Berlin 07

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Xi…

Others…

Select the relevant criteria

Environmental criteria

Usage criteriaSelection of legitimate uses which’s surface is significant

compared to the whole surface of the GWB

Surface waters and wetlands Drinking water Industry Crops

Identify the lowest criteria’s value

Deriving a criteria’s value for each of the relevant

criteria

X2 X3 X4

Compare to NBL

X1= EQS*AF1/DF1

4. Methodology to derive TV

Remarks 2 types of criteria

« Saline and other intrusion » criteria to be linked with NBL

4.2 Methodology4.2 Methodology

Source: A. Blum; WG C meeting Berlin 07

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4. Methodology to derive TV

4.2 Methodology

NBL

Case 1

Most stringent criteria’s value

TV

NBL

TV

Case 2

Remarks to define by each

Member State

Using a risk assessment

MS can define lower TVs if relevant

Minimum approach to fit WFD/GWD objectives

Source: A. Blum; WG C meeting Berlin 07

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Reporting

Information to provide Scale for reporting Number of GWB at risk List of parameters indicative of and relevant to the associated risk General information Range of concentrations for each parameter

National

Size Relationships with surface waters and GWDTE Threshold values for each parameter responsible for a risk NBL (in the case of naturally occurred parameter) Environmental quality objectives and other standards

Information for each groundwater body at risk

Information on toxicology, eco-toxicology, persistence, bioaccumulation, dispersion of the pollutant

Body or group of bodies of groundwater

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GWB Delineation

GWB characterisation

Risk assessment and Threshold values

References

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References: CIS Guidance documents

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References: Draft CIS Guidance documents

Guidance on the application of the term „direct and indirect inputs“ in the context of the Groundwater Directive 2006/118/EC - draft

Guidance on Groundwater in Drinking Water Protected Areas –draft

Common methodology for the establishment of groundwater threshold values –draft

Groundwater chemical status - draft