1. vrije Universiteit amsterdam Institute for Environmental Studies (IVM) 1 Sampling seafood for assessment of TBT exposure : Did we get it right? EU-supported project QLK1-2001-01437 “OT-SAFE” Willemsen, FH 1, Morabito, R 2, Wegener, JW 1

2. vrije Universiteit amsterdam Institute for Environmental Studies (IVM) 2 Aim of OT-SAFE  “to assess the risk of TBT in seafood for European consumers”  Tolerable daily intake has been established at (0.25μg/kg bodyweight)  Leaves : –differences in bodyweight (differs with age, sex, geographic region, etc.) –exposure

3. vrije Universiteit amsterdam Institute for Environmental Studies (IVM) 3 Estimating the exposure level  Exposure through seafood only -realistic scenario  Exposure = Σ Seafood t,x * TBT-content t,x –For as many foods as feasible with: –t= time of the catch (if necessary) –x= location (if necessary)

4. vrije Universiteit amsterdam Institute for Environmental Studies (IVM) 4 Estimating the exposure level  Necessary data is consumption data  Dutch Seafood Consumption (1997) Total (x1000 tns/y) Per capita (kg/y) Production550- Internal Supply (food use) 25216.1 Consumption(58)3.7

5. vrije Universiteit amsterdam Institute for Environmental Studies (IVM) 5 Seafood consumption data  Food consumption data SouceAvailabilityUsefulness FAO/EurostatGoodPoor Household budget surveys ??Average Food consum. surveys VariesGood Consumption pattern surveys ??Excellent

6. vrije Universiteit amsterdam Institute for Environmental Studies (IVM) 6

7. vrije Universiteit amsterdam Institute for Environmental Studies (IVM) 7 Seafood consumption data (NL)

8. vrije Universiteit amsterdam Institute for Environmental Studies (IVM) 8 Sampling strategy –Expected TBT-levels from literature –Consumption figures (as detailed as possible) –Calculate expected relative contribution –If feasible, differentiate for location

9. vrije Universiteit amsterdam Institute for Environmental Studies (IVM) 9 Estimating the exposure level  Figures on TBT-content  First estimate (NL-example) based on taxonomic groups and regional specifics: Taxon. group Av. conc. (ng/g TBT/net weight) Range (ng/g TBT/net weight) Molluscs 2281816-1 Fish 2056-2 Cephalopods 354655-8 Crustaceans 814-3

10. vrije Universiteit amsterdam Institute for Environmental Studies (IVM) 10 Estimating the exposure level, example

11. vrije Universiteit amsterdam Institute for Environmental Studies (IVM) 11 Sampling procedure  174 samples in total  28 species  Almost 50% of samples are molluscs and cephalopods

12. vrije Universiteit amsterdam Institute for Environmental Studies (IVM) 12 So did we get it right?  Pro: Preliminary data suggests that the assumptions are born out, e.g. low conc. in pelagic fish  Contra: There is still a spread in concentrations, that we cannot explain