Katrien Delbeke, ECI, Frank Van Assche,IZA- Europe Frank Van Assche,IZA- Europe On behalf of the...
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Katrien Delbeke, ECI, Katrien Delbeke, ECI, Frank Van Assche ,IZA- Europe Frank Van Assche ,IZA- Europe On behalf of the Eurometaux Water Project Team On behalf of the Eurometaux Water Project Team Accounting for bioavailability and natural background under the WFD Perspective of the Metals Industry
Katrien Delbeke, ECI, Frank Van Assche,IZA- Europe Frank Van Assche,IZA- Europe On behalf of the Eurometaux Water Project Team Accounting for bioavailability
Katrien Delbeke, ECI, Frank Van Assche,IZA- Europe Frank Van
Assche,IZA- Europe On behalf of the Eurometaux Water Project Team
Accounting for bioavailability and natural background under the WFD
Perspective of the Metals Industry
Slide 2
Content WFD issues for metals Metal bioavailability Metal
background levels Conclusions
Slide 3
Water quality standards setting for metals: issues For the EQS
setting on metals, a number of specific characteristics have been
recognized: o Some Metals are data-rich and the ecotoxicity data
quality is variable o All are Natural Elements, occurring with
varying background levels in water o Bioavailability is key to
understand the possible ecological impact of metals
Slide 4
From RA to WFD: ecotoxicity data For several metals, EU risk
assessments have been made Approved data sets are available RA data
sets checked for quality and relevancy But the EU RA = generic
assessment on EU-wide scale EU RA = considers uncertainties at an
EU wide scale WFD = National (river basin) assessments WFD = more
refined approach, more specific to local water conditions WFD =
generic + site - specific information (BG & bioavailability)
uncertainties reduced for EQS setting
Slide 5
Integrating Metal bioavailability In EQS setting
Slide 6
- -Corrections for metal Bioavailability have been applied in
EU Risk Assessments - Cd : Hardness correction on dissolved metal
concentrations - Zn, Ni, Cu : BLM correction on dissolved metal
concentrations - -Bioavailability phrasing of the WFD (2000/60/EC):
- 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
Use of bioavailability in EU regulations
Slide 7
Tiered approach (UK, WFD proposal) Tier 1 : EQS = reference
PNEC Check PEC against ref PNEC If exceedence: go to tier 2 Tier 2
: account for metal bioavailability Check PEC against site specific
PNEC Tiered approach to account for bioavailability
Slide 8
Evidence on site-specific toxicity for - Cd - - Zn - - Ni - -
Cu - -. Cu Importance of bioavailability for metal toxicity Zn
Toxicity of metals to Daphnia magna in different EU surface waters
Up to factor 30 difference in EC 50 D.magna explained by
bioavailability
Slide 9
The BIOTIC LIGAND MODEL- BLM Principles of metal toxicity: Key
target for metal toxicity = gills or gill-like structures
Slide 10
BLM toxicity prediction from water characteristics zinc example
Algae Toxicity predicted within factor 2 Daphnids Toxicity
predicted within factor 2 Original unexplained variability : factor
10-50 After BLM correction : unexplained variability : factor
2-3
Slide 11
Criteria for use of bioavailability in RA & EQS For at
least 3 dissimilar groups, for a range of test media, demonstrate,
that NOECs variability < factor 5
Slide 12
Scientific evidence : BLM developments & validations - some
other species Unexplained variability : from factor 70 to factor
2-3
Slide 13
Bioavailability translator (BLM) fish, invertebrates, algae
Bioavailability translator (BLM) fish, invertebrates, algae SSD
Site-specifc EQS Normalised NOECs ( related to site-specific water)
Individual NOECs (varying pH, H, DOC,) Refined Risk ratio = PEC/EQS
site Incorporation of Bioavailability in EQS setting
Slide 14
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 Full
BLM normalization case example: Cu in the river Rhine Risk in Rhine
if PEC dissolved > 8 g Cu/L Normalisation of NOECs with c-BLM
Normalised SSD
Slide 15
Specific EQSs for different EU waters example: Cu
Slide 16
Water parameters driving Bioavailability and available
bioavailability tools Key parameters driving bioavailability for
Cu, Zn, and Ni are DOC and pH Other drivers can be Ca, Mg,
alkalinity, Na, Dependent of the metal Available tools: Cd:
Hardness algorithm Cu, Zn, Ni: user-friendly software for BLM
calculations
Slide 17
Remaining issues for discussion under WFD Measurements of
bioavailability parameters 1) Temporal variability? make average?
2) Include in all monitoring, or only in cases of exceedences of
the ref PNEC? = Tiered approach?
Slide 18
Variability in bioavailability parameters Seasonal versus
geographic variability in BLM variables : DOC From : Kramer et al.,
2004
Slide 19
Background levels Metals are Natural Elements, occurring in
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 ISSUES : - How to account for
natural background levels - How to set a natural background
level
Slide 20
How to account for 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
are based on total metal levels. EQS = PNEC (site-specific).
Slide 21
Tiered approach (UK, WFD proposal) -Tier 1 : total risk
approach (site specific) EQS = PNEC (site-specific) If exceedence:
tier 2 -Tier 2 : account for background level EQS = BRC + MPA - BRC
= background reference concentration - MPA=maximum permissible
addition (= PNEC - background of test media) How to account for
natural background levels
Slide 22
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).
Slide 23
How to set natural background levels CMA - AMPS (June 2004)
evaluated the FOREGS ambient geochemical baseline data for Europe
(http://www.gsf.fi/foregs/geochem/) as possible EU wide reference
BRC values http://www.gsf.fi/foregs/geochem/ The FOREGS database
has good merits: - high quality database - consistency in sampling
- consistency in sampling and analysis Sampling in unaffected areas
- Sampling in unaffected areas BUT, the scale of sampling is rather
coarse and THUS, local data are still preferred
Slide 24
Example of Foregs maps
Slide 25
Initial Tiered approach for compliance checking Tier 1 :
Reference EQS National pH,DOC: Within Reference EQS boundaries?
Local EQS Within BLM Boundaries? Case by case evaluation Local
Background Added EQS Compliance? C diss