1. Common methodology for the establishment of groundwater threshold values
Working Group C
Ariane BLUM, Hélène LEGRAND (France)
Hans Peter BROERS (Eurogeosurveys)
Berlin, 3 May 2007
European Commission - DG Environment
Unit D.2: Water and Marine

2. Outlines of the presentation
Presentation of the draft
Exchanges within the WGC-2 drafting group
Timetable

3. Methodology to derive threshold values
Table of contents
Purpose and scope
Reminding the mandate and why this paper has been drafted
Background
Giving a common understanding of the GWD Article 3
General principles
Giving the key concepts to apply the methodology
Methodology to derive threshold values
Explaining the recommended methodology

4. Mandate: WGC 2007-2009 1. Purpose and scope
STRATEGIC CO-ORDINATION GROUP
PLENARY WG C
CHAIR: COM
CO-CHAIR: AT
Water scarcity expert group
Priority Substances
Working Group E
Programme of Measures
Lead: ???
Co-lead: ???
Compliance & Trends
Lead: JG, RW
Co-lead:HL,AB,HPB
Integrated risk
assessment
Lead: DM, TT
Co-lead: ???
Chemical Monitoring
Lead: IT
Co-lead: JRC-IES
Methodology for the derivation of threshold values
Status,compliance and trends guidance
Strong link with the « Status, compliance and trends » guidance document!!

5. 1. Purpose and scope Our purpose! 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)
 Full protection of groundwater
Our purpose!

6. 2. Background 2.1 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
2.2 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
Surface water, GWDTE, human uses (including future uses), saline or other intrusions, material property, amenities

7. 2. Background 2.3 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
2.4 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)
2.5 Information to be reported in the RBMP
2.6 Transboundary GWB

8. 3.1 Need for a conceptual model
3. General principles
3.1 Need for a conceptual model
conceptual model as described in othe WGC guidance documents and as proposed in the GWD (Article II.A)

9. 3. General principles 3.2 Aquifer typologies 3.3 Type of monitoring
To remind GWB heterogeneity
As a support for the derivation of NBL
3.3 Type of monitoring
Link with monitoring strategies
3.4 Attenuation and dilution issues (SW, GWDTE)
Definition of dilution and attenuation concepts
Justification for the use of AF and DF
3.5 Confidence in the conceptual model
To remind that the relevancy of the TV depends on the confidence in the conceptual model
To remind that many uncertainties exist (open process!)

10. 4. Methodology to derive TV
4.1 Preliminary steps

11. 4. Methodology to derive TV
Others…
Select the relevant criteria
Environmental criteria
Usage criteria
Selection 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
4.2 Methodology
Remarks
2 types of criteria
« Saline and other intrusion » criteria to be linked with NBL
Xi…

12. 4. Methodology to derive TV
Remarks
e to define by each Member State
Using a risk assessment
MS can define lower TVs if relevant
NBL
Case 1
Most stringent criteria’s value TV e
Case 2
 Minimum approach to fit WFD/GWD objectives

13. 4. Methodology to derive TV
4.2.B Criteria’s value for SW/GWDTE
Use EQS or any other relevant ecotoxicological value
Use Attenuation Factor (AF) and/or Dilution Factor (DF) if possible
4.2.C Criteria’s value for the « legitimate uses »
Drinking Water Standards in DWPA
Case by case approach for other uses
4.2.C Criteria’s value for « saline or other intrusion»
Relevant value = NBL

14. Outlines of the presentation
Presentation of the draft
Exchanges within the WGC-2 drafting group
Timetable

15. Exchanges within the WGC-2 drafting group
Reminder of the schedule
9 march: circulation of draft version 1
10 April: comments from WGC-2 members
20 April: circulation of draft version 2
2 May: drafting group WGC-2 meeting
Main issues of drafting group meeting
Links with the guidance document on « status, compliance and trends »
 Both documents will be merged
More details on:
Groundwater « itself » as a receptor
One single TV per groundwater body (link with « status and trends » document)
Epsilon value
Taking the treatment processes into account in DWPA (Article 7.3 and « baseline » concept)

16. Tentative timetable Timetable
23 May 2007: circulation of a new version
21 September 2007: Lisbon plenary WGC
October 2007: submission to SCG?

17. THANK YOU FOR YOUR ATTENTION!
Acknowledgements: WGC-2 members, Johannes GRATH (UBA-A), Rob WARD, Cath TOMLIN (EA)
THANK YOU FOR YOUR ATTENTION!