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

| Slide 2 Contents GWB Delineation GWB characterisation Risk assessment and Threshold values References

| Slide 3 GWB Delineation GWB characterisation Risk assessment and Threshold values References

| Slide 4 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

| Slide 5 WFD – Groundwater body

| Slide 6 GWB Delineation GWB characterisation Risk assessment and Threshold values References

| Slide 7 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.”

| Slide 8 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 Characterisation Requirements in the WFD  Basis for Risk Assessment

| Slide 9 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 Characterisation Requirements in the WFD

| Slide 10 The Conceptual Model

| Slide 11 GWB Delineation GWB characterisation Risk assessment and Threshold values References

| Slide 12 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

| Slide 13 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 NO 3 and/or pesticides if relevant Taking the minimum list into account The links between Article 3 and Article 6 Article 3Article 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

| Slide 14 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 RBMP Transboundary GWB Source: A. Blum; WG C meeting Berlin 07

| Slide 15 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, …)

| Slide 16 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?

| Slide 17 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

| Slide 18 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

| Slide 19 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 – to transfer background values from similar aquifer types in Europe to Latvian aquiferswww.wfd-bridge.net

| Slide 20 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.

| Slide 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

| Slide 22 Xi… 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 X2X2 X3X3 X4X4 Compare to NBL X 1 = EQS*AF 1 /DF 1 4. Methodology to derive TV Remarks 2 types of criteria « Saline and other intrusion » criteria to be linked with NBL 4.2 Methodology Source: A. Blum; WG C meeting Berlin 07

| Slide 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

| Slide 24 Reporting

| Slide 25 GWB Delineation GWB characterisation Risk assessment and Threshold values References

| Slide 26 References: CIS Guidance documents

| Slide 27 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