Refined determination of metal availability in sediments (Acid Volatile Sulphide measurements) K. Delbeke, on behalf of Metals assoxiations and Euras

Proposal for monitoring sediments for EU Metal Risk Assessments “ Proposal for a multi-metal monitoring campaign aiming at a refined determination of metal availability in sediments”  The proposal was presented and agreed by member states at TC NES III ’06  A Steering Group was set up composed of : members of the TC NES, monitoring experts from the member states, and Industry representatives.

SEM-AVS concept application AVS = Acid Volatile Sulfides: sulfides liberated by the cold extraction of sediment in approximately 1 M HCl SEM= Simultaneously Extracted Metals: refers to the metals associated with the sulfides and any other metal bearing phase that is extracted in the cold HCl extraction used for AVS Principle: IF ∑ SEM-AVS <1, then NO toxicity ΣSEM = SEM Cu + SEM Pb +SEM Cd + SEM Zn + SEM Ni AVS affinity copper > lead > cadmium > zinc > nickel

Application AVS in risk characterisation Application in RA PEC bioavailable = PEC total - AVS Risk Characterisation = PEC bioavailable Sediment PNEC Use measured data if available  Use RWC AVS if no data available RWC = 10th percentile from Flanders database Regional/Local AVS approachl?

TCNES discussions on default AVS  The Flanders database: the largest database (n = 200 sediments) available on SEM-AVS data in the EU. 10Percentile AVS based on Flanders database was suggested as default AVS value for Europe= 0.77 µmol/g  TC NES questioned the representativeness of the Flanders region for all of Europe. Proposed way forward for ongoing EU metal risk assessments:  A multi-metallic conclusion i) program aimed at collecting AVS data in relevant river systems in order to check the default values and fill data gaps in AVS in other EU regions.

TCNES agreement: Selection of EU regions Selected regions : - Northern Europe (Scandinavian countries) - United Kingdom - Southern Europe - Midland rivers (already covered by Flanders

Proposal for monitoring sediments for EU Metal Risk Assessments “ EURAS Proposal for a multi-metal monitoring campaign aiming at a refined determination of metal availability in sediments”  A proposal was presented and agreed by member states at TC NES III ’06  Interests was solicited through TCNES and WFD experts Interests were obtained from Fi, UK, Sp, Dk, De  An AVS Steering Group was set up, composed of experts from the Fi, UK, Sp, Dk,De, and Ind A first tel conference took place

AVS steering group agreements  MOU drafted by UK, to be signed by all  Sediment collection proposal Sampling rotocol agreed : upper 5 cm, using core sampler or grab sampler Sampling time agreed : Spring 2007  Sampling sites Main river basins/lakes Depositional sediments from the larger rivers/lakes that are at the higher end of the metal exposure spectrum (between 25-75th percentiles of the region specific metal concentrations)  Laboratory Analysis : Analysis under approved standard procedures at VITO  Number if sites and data analysis under discussion Power analysis performed, demonstrating that 25 samples is enough (Dk & De)

EURAS Power analysis for sample size Principles 1.One sided difference 2.Detection of difference between median values Flanders 50P= 8.7 µM/g Power analysis (80%) Statistically power of with 25 samples when: AVS <4.2 µmol/g Statistical power ok 4.5 µmol/g

Conclusion  The AVS sampling campaign will allow for extending the derived default AVS values towards other EU regions.  A steering group meeting agreed on the technical details related to the sampling and analysis.  The sampling program will be conducted in Spring 2007 (April–June). Results are expected in Autumn  Current co-operation with MS allows the start of the program Scandinavian country : Finland UK Southern country : Finland Germany decided not to co-operate Additional co-operation with DK would be appreciated

Main conclusions - Thanks for the co-operation