WFD Lille Assessment of Metal Bioavailability and Natural Background Levels WFD Monitoring from the Perspective of Metals Industry

Transcription

1 WFD Lille 2007 Assessment of Metal Bioavailability and Natural Background Levels WFD Monitoring from the Perspective of Metals Industry Katrien Delbeke, ECI, Patrick Van Sprang (Euras( Euras), Hugo Waeterschoot (ENIA), Frank Van Assche (IZA- Europe), Lidia Regoli (IMOA), Andy Bush (LDAI), William Adams (Rio Tinto), Lynette Chung (Eurometaux) Content WFD Issues for metals Metal background levels Metal bioavailability Conclusions

2 WFD issues - Metals in EU water regulations In Europe, metals are regulated by: The IPPC directive (local sites) Directives 76/464/EEC (2006/11/EC): Pollution is defined as a discharge by man, directly or indirectly, of substances or energy into the aquatic environment, the result of which are such to cause hazards to human health, harm to living resources and to the aquatic ecosystems. The 2000/60/EC WFD contains a list of priority substances, identified in accordance with Article 16 (2) substances shall be prioritised for action on the basis of risk to or via the aquatic environment, identified by risk assessments and targeted risk-based assessments. - Hg & Cd are identified as priority hazardous substances, - Ni & Pb are identified as priority substances - Other pollutants are to be prioritised at National level = prioritisations based on risks Background levels -Metals are Natural Elements, occurring with varying background levels Background corrections under the WFD (2000/60EC): - If natural background values are higher than the EQS member states may take this into account when assessing the monitoring results against the EQS - EC may/must develop the different methodologies for taking into account for metal backgound levels ISSUES : - How to use natural background levels - How to set a natural background level

3 How to use natural background levels Zn RA and AMPS (2004): added risk approach (ARA) EQS = BRC+ MPA - BRC = background reference concentration - MPA=maximum permissible addition (= PNEC-background test media) In Cd, Pb, Ni & Cu RA, effects based on total metal levels. EQS = PNEC (site-specific). How to use natural background levels Tiered approach (UK, WFD proposal) -Tier 1 : total risk approach (site specific) EQS = PNEC (site-specific) If exceedence -Tier 2 : account for background level EQS = BRC+ MPA - BRC = background reference concentration - MPA=maximum permissible addition (= PNEC-background test media)

4 How to set natural background levels CMA - AMPS (June 2004) provided some possible methods for BRC values to be chosen in a particular river basin: Analysed values for trace Metal Concentrations in Pristine Areas (with assurance that river basin is pristine or nearly so) Trace Metal Concentrations in Groundwater (shallow and/or deep) Expert Judgement (incl. International agreements; River basin commissions). How to set natural background levels CMA - AMPS (June( 2004) evaluated the Foregs ambient geochemical baseline data for Europe ( as possible EU wide reference BRC values The FOREGS database has good merits: - high quality database - consistency in sampling and analysis BUT, the data sampling is rather coarse ( )) and THUS, local data are preferred

5 Example of Foregs maps Metal bioavailability

6 Scientific evidence: Metal bioavailability Bioavailability of metals are influenced by Physical and chemical form (metal speciation) bound to particles (in-)organic complexes free ions Environmental conditions acidity, salinity redox potential presence of other elements (e.g., Ca, OC..) Use of bioavailability EU regulations Bioavailability corrections for metal have been applied in EU RAs - Cd : Hardness correction on dissolved metal concentrations - Zn, Ni, Cu : BLM correction on dissolved metal concentrations Bioavailability corrections under the WFD (2000/60EC): - In the case of metals the EQS refers to the dissolved concentration - if ph, Hardness and other water quality parameters affect the bioavailability of metals, member states may take this into account when assessing the monitoring results against the EQS - EC may/must develop the different methodologies for taking into account bioavailability

7 Scientific evidence : Importance of bioavailability for metal toxicity Toxicity of metals to Daphnia magna indifferent EU surface waters 48h-EC50 in µg Cu/L NOEC (µg Zn/L) Cu Zn Location Factor 30 difference in EC 50 D.magna = bioavailability Evidence on site-specific toxicity for -Cd -Zn -Ni -Cu -. The BIOTIC LIGAND MODEL- BLM Principles of metal toxicity: Key target for metal toxicity = gills or gill-like structures Ca Mg Na + H Competition organism-water interface DOC Organic complexes Cu 2+ Toxicity Cu 2+ toxic action or transport sites = biotic ligand (BL) Toxicity? Inorganic complexes (E.g. carbonates, hydroxides) WHAM (Tipping, 1994) Gill GSIM Site (Pagenkopf, Interaction Model 1983) (Pagenkopf, FIAM (Morel, 1983)

8 Scientific evidence : BLM developments & validations D. Magna BLM development and validation data Santore, 2001, De Schamphelaere et al., Scientific evidence : BLM developments & validations- other species Measured versus predicted copper EC10 for Hyridella depressa 48hr valve movement, using the chronic D. magna model for the EC10 predictions Measured versus predicted copper EC50 for Lampsilis early life stage, using the chronic D. magna model for the EC50 predictions Predicted EC10- µg Cu/L 100 Predicted EC50- µg Cu/L Measured EC10- µg Cu/L Measured EC50- µg Cu/L Measured versus predicted copper EC50 for Hyalella azteca 1week LC50 using the chronic D. magna model for the LC50 predictions Measured versus predicted copper NOEC for Brachionus calcyflorus 4!hr NOEC using the chronic D. magna model for the NOEC predictions Predicted EC50- µg Cu/L 100 Predicted NOEC- µg Cu/L Measured EC50- µg Cu/L Measured NOEC- µg Cu/L

9 Criteria for use of bioavailability in RA & EQS Full BLM Incorporation- principles Individual NOECS (varying ph, H, DOC) Bioavailability translator (c-blm) «fish, invertebrates, algae» Normalised NOECs ( site-specific water) Site-specifc PNEC Risk = PEC/PNEC site

10 Full BLM normalization - case examples Water chemistry - Rhine ph : 7.8 DOC : 2.8 mg/l Ca : 65mg/L Mg : 11 mg/l Na: 37 mg/l K : 56 mg/l Alkalinity : 119 mg CaCO3/L (c-blm) Percentile (%) 100 RHINE µg Cu/L Risk in Rhine if C dissolved > 8 µg Cu/L ph DOC Ca Mg Na K Alk HC5 mg/l mg/l mg/l mg/l mg/l mg/l µg Cu/L River Otter River Teme Ditch River Rhine River Ebro Lake Monate Lake Sweden Bioavailability parameters and tools Key BIOAVAILABILITY PARAMETERS - Cd = Hardness function -Zn = BLM excel sheet ph, Hardness, DOC - Ni, Cu = BLM user friendly software ph, Alkalinity (HCO3-) DOC Ca, Mg (or total hardness), Na

11 Remaining issues for discussion Measurements of bioavailability parameters For all monitoring or only cases of exceedences of a RWC-PNEC? = Tiered approach? Measurements of bioavailability parameters Temporal measurements, make average? Remaining issues for discussion Seasonal versus geographic variability in BLM variables : DOC Seasonal variations in DOC levels in 6 Dutch rivers DOC (mg/l) Ja A Jul Oc Ja A Jul Oc Ja A Jul Oc Ja A Jul Oc Ja A Jul Oc Ja A Jul Oc Beemster Vinkeveen Regge Brook Rhine Meuse From : Kramer et al., 2004

12 Conclusions Key Conclusions Criteria have been set on the acceptance of bioavailability models (eg BLMs) for use in RA s and EQS settings. The implementation of background corrections in an added risk approach has been proposed. The derivation of appropriate river basin specific background values need to be established. For several metals (Zn, Cu, Ni (almost finalized)),user-friendly bioavailability models have been developed by industry and tested by UK & NL. They are available to water authorities.

13 Key Conclusions The implementation of bioavailability corrections means that bioavailability parameters (ph, DOC, Ca, Mg, Na, alkalinity) are to be measured. Some questions remain : seasonal variations, tiered approaches Industry recommendation The EC is to set-up the methodology for bioavailability and background corrections. Past co-operation between industry and EU-MS, in the framework of RAs and bilateral discusisons, may be useful for such methodological development.