Approaches and tools for ecological risk assessment at different levels of contamination

Transcription

1 Toward common references for risk assessment of contaminated sites in Europe Approaches and tools for ecological risk assessment at different levels of contamination

2 Ecological Risk Assessment Technical / scientific support for decision-making under uncertainty Implies goal of decision Implies possible alternative outcomes Implies uncertainty Implies decision Different roles Role of scientist: risk assessor Role of decision-maker: risk manager 2

3 Step 1: Target formulation General environmental protection? Environmental Quality Criteria Specific environmental protection? e.g., red list species? Site-specific evaluation? Physico-chemical: no spread beyond current contour line? Ecological: Complete clean-up possible? Recovery? Partial clean-up? To which level? Autonomous recovery? Decision type One-site decision? Ranking a series of sites? 3

4 Step 2: Analyse the problem, choose approach What is the problem Define desired future land use What is limiting for that Contour / surface area of contamination? Single compound or mixture? Level of contamination? Sensitivity of particular species? Which approaches and tools can be used? Modeling Empirical Both 4

5 Gradual contamination problem EQC, e.g. Target Value (single compound) EQC Intervention Value (single compound) Visible damage (mixture) Contamination 5

6 Choice of tools Environmental Quality Criterion e.g. Target Value (single compound) EQC Intervention Value (single compound) Visible damage (mixture) Contamination 6

7 Problem 1 7

8 Problem (1): problem is in lower range Environmental Quality Criteria: Modeling result!!! Target Value < Problem < Intervention Value Example: Species Sensivity Distributions Model theory Tools: ETX (2005) E-toxBase (2005) 8

9 Theory of SSDs, PAF and mspaf PAF (potentially affected fraction) HC 50 Cd Concentration in soil (mg/kg) Multi-substance PAF = 1 - ((1 - PAF1)(1 - PAF2)..(1 - PAFn)) 1 site = 1 result!!!!! 9

10 Tool: e-toxbase > data entries 2900 species 5100 compounds 910 Modes of Action Meta-data Quality Time-stamp Data-owner. Export to MS-Excel Transfer to ETX 10

11 ETX (2005) Exposure data From site Per compound Sensitivity data From e-toxbase Per compound Result PAF mspaf JPC per site 11

12 ETX-out 1: SSD Goodness of fit tests SSDparameters 12

13 ETX out 2: Joint Probability Curve per site Moderate site Ideal site None of sampling spots shows exceedance HC5 Extreme site 13

14 National-scale evaluation: 6000 sites Sediment deposition on land Evaluation of local risk on land > 6000 sites Sediment pollution Soil quality Cause of problem mspaf PAF Koper PAF Cadmium PAF Fluorantheen PAF Chroom PAF Indeno(123cd)pyreen PAF Nikkel PAF Benzo(a)pyreen PAF Benzo(ghi)peryleen PAF Chryseen PAF Kwik PAF Anthraceen PAF Benzo(a)anthraceen PAF Benzo(k)fluorantheen Number of sites With exceedance problem 14

15 Take home Modeling for moderately contaminated sites Logical: just beyond EQC, from modeling Tools available ETX: versatile, many types of problems Within-site: spatial aspects Among sites: ranking E-toxBase: fuel for ETX Additional tools: ecochem-base / expo-base Theory development ongoing Spatial / temporal aspects Specific Toxic Mode of Action Validation Et cetera 15

16 Problem 2 16

17 Problem is in higher range chemistry risk toxicity ecology Approach: Triad Aim: use pragmatism to reduce conceptual uncertainties Tactics: independent lines of evidence Chemistry mspaf Toxicity - Bioassays Ecology Field Inventories 17

18 Triad: Theory and Tools Tiered approach Tier 1: simple quick Upper tiers: better tailored to problem - slower Within a tier All observations scaled from 0 1 Calculate Coefficient of Variation Stop when CV < value (e.g. 20%) Triad Aspect Parameter Sample A B C Chemistry Sum TP metals Toxicology Microtox Ecology nematods biomass Integrated risk deviation risk risk risk

19 Triad: tier 2 Overall integration Sample Triad Aspect Parameter A B C (1) Chemistry Sum TP metals (2) Toxicology Microtox Lettuce germ Lettuce growth Bait lamina integration (3) Ecology nematodsbiomass nematodsmi integration Integratedrisk risk deviation

20 Tier 3 Tier 3 Triad Aspect Parameter A B C Chemistry TP bioavailable Toxicology Microtox Bait lamina test Worms growth Worms survival Worms reproduction Lettuce germination Lettuce growth integration Ecology Arthropods asex. reprod Arthropods fungiv. grazers Arthropods predators MO thymidine incorp MO biomass MO nitrification protozoans nematods biomass nematods MI integration chemical risk: toxicity risk: ecology risk: Integrated risk deviation

21 Triad: theory and tools Bioassay-Base Contains: bioassay types Earthworms Plants Contains: bioassay results Site characteristics (ph, OM, ) Contamination levels Bioassay results of past assessments In planning phase Support for selecting bioassays for problem 21

22 Take home Weight of Evidence for higher contamination level Logical: effects to be expected Tools available (planned) Triad formalized weight of evidence approach Bioassay-Base: (planned) selection of bioassay Additional tools: ecochem-base e-toxbase and ETX Other approaches: body residues. Theory development ongoing Spatial / temporal aspects Et cetera 22

23 Problem 3 23

24 Highest contamination level Just visual inspection 24

25 Overall conclusions Ecological risk assessment (Pragmatic) Theories available Tools available and under development Fit into envisioned framework Helpfull enough for decision making Weaker on Systematic approach : uniform framework / test / adopt Despite uniform approach should be tailored to problem Spatial aspects: theory? Temporal aspects: theory? Both in relation to ecological processes To be done: framework + approaches + tools 25