Definition, calculation and measurement of overall persistence in the environment, P OV and long-range transport potential, LRTP

Transcription

1 dik van de meent & anne hollander, rivm bilthoven, nl; martin scheringer, eth zurich, ch; kevin jones, lancaster univ, uk Definition, calculation and measurement of overall persistence in the environment, P OV and long-range transport potential, LRTP

2 UNECE/CLRTAP, UNEP/Stockholm, EU Persistent Bioaccumulative Effects upon long-range transport Toxic Yes? POP or PBT Restricted or banned POP-ness criteria - Overall persistence in the environment P OV - Long-range transport potential LRTP

3 Persistence and long-range transport Screening criteria for conventions - single-media half-lives - spirit Air: 2 d Water: 30 d (60d) Sediment/Soil: 180 d Avoid presence after use: P OV (<??) Avoid presence/ects elsewhere: LRTP (<??)

4 SETAC Pellston Workshop P OV & LRTP 1998

5 SETAC Pellston Workshop Pensacola 2008 "Science-Based Guidance and Framework for the Evaluation and Identification of PBTs and POPs - Muir, Klecka, Van Wijk - Jan 27- Feb 1, 2008, Pensacola, FL 50 participants - WG2 (Jones, Matthies, Scheringer, Simonich, Van de Meent) on use of Pov/LRTP indicate instead of identify update definitions? field validation? To be published 2009 M Scheringer, KC Jones, M. Matthies, S Simonich, D van de Meent Multimedia Partitioning, Overall Persistence, Long-Range Transport Potential Integrated Environmental Assessment and Monitoring, in review Today: comparing P OV and LRTP to field data

6 Pensacola proposal Meaningful use of P OV and LRTP - Definition - Calculation - Field measurement Definitions - P OV : time average life time of molecules in the environment time(degraded) time(emitted) - LRTP: length average distance traveled by molecules in the environment place(degraded) place(emitted)

7 mass emission Pensacola proposal Calculating P OV - average life time of molecules in the environment 9E+03 8E+03 7E+03 6E+03 5E+03 4E+03 3E+03 2E+03 1E+03 0E time 9E+03 8E+03 7E+03 6E+03 5E+03 4E+03 3E+03 2E+03 1E+03 0E time

8 mass Pensacola proposal Calculating P OV - average life time of molecules in the environment 9E+03 8E+03 7E+03 6E+03 5E+03 4E+03 3E+03 2E+03 1E+03 AOC: presence in the environment 0E time

9 mass Pensacola proposal Calculating P OV - average life time of molecules in the environment 9E+03 8E+03 7E+03 AOC 6E+03 5E+03 4E+03 3E+03 2E+03 1E+03 0E time

10 mass Pensacola proposal Calculating P OV - average life time of molecules in the environment 9E+03 P OV = t eq 8E+03 7E+03 6E+03 5E+03 4E+03 3E+03 2E+03 1E+03 0E time

11 mass Pensacola proposal Calculating P OV - average life time of molecules in the environment 9E+03 P OV = t eq 8E+03 7E+03 6E+03 5E+03 4E+03 3E+03 2E+03 1E+03 0E time P ov t eq 0 M dt M 0 0 M 0 e M k t 0 dt 1 k

12 mass emission Pensacola proposal Calculating P OV - average life time of molecules in the environment 1E+02 1E+02 8E+01 6E+01 4E+01 2E+01 0E time 1E+03 1E+03 8E+02 P ov 0 0 M dt E dt M E ss 1 k 6E+02 4E+02 2E+02 0E time

13 emission mass Pensacola proposal Calculating P OV - average life time of molecules in the environment 5E+02 4E+02 4E+02 3E+02 3E+02 2E+02 2E+02 1E+02 5E+01 0E time P ov 0 M dt E dt 3E+03 3E+03 2E+03 2E+03 1E+03 5E+02 0E time Measuring P OV - historical emissions - historical field data - sufficiently long after emission stop 0

14 Pensacola proposal Calculating LRTP - average distance traveled by molecules in the environment LRTP x eq u u 2 2k 4k D Measuring LRTP - field gradient at steady state

15 Field data? Scarce! - P OV : Barber et al. (2005) review historical emission data HCB environmental monitoring data HCB JL Barber, AJ Sweetman, D van Wijk, KC Jones Hexachlorobenzene in the global environment: Emissions, levels, distribution, trends and processes Science of the Total Environment, 49(2005), 1-44 complementary multi-media mass balance modeling - LRTP: Breivik et al. (2006) paper measured half-distances PCBs and BDEs into Arctic K Breivik, F Wania, DG Muir, M Alaee, S Backus, G Pacevicius Empirical and modeling evidence of the long-range atmospheric transport of decabromodiphenyl ether Environmental Science and Technology, 40(2006),

16 Multimedia mass balance modeling with SimpleBox Substances evaluation (EUSES) GLOBAL SCALE CONTINENTAL SCALE REGIONAL SCALE

17 SimpleBox HCB model Global: northern hemisphere - 2.5x10 8 km 2 Arctic 1.7x10 7 km 2 26% land Moderate 9.9x10 7 km 2 50% land Tropical 1.3x10 8 km 2 30% land Continental: W-Europe - 9.6x10 6 km 2, 53% land Regional: North Sea area - 7.8x10 5 km 2, 58% land

18 Jonathan Barber s data used with SimpleBox Emission estimates Pacyna et al. - EU only; no emissions elsewhere - regional : continental = 1 : 9 - air : water : soil = 0.01 : 0.09 : emissions start 1950 Concentrations simulated regional, continental, global - air, fresh water, coastal seawater, oceans, sediments, agricultural (loaded) soil, natural (unloaded) soil Compared to monitoring data

19 Model simulations AIR 6,0E-10 5,0E-10 Model simulation HCB in EU Air (g/m3) 1,2E-10 1,0E-10 Model simulation HCB in Background Air (g/m3) temperate 4,0E-10 8,0E-11 tropical 3,0E-10 t 1/2 = 10 yr 6,0E-11 t 1/2 = 17 yr 2,0E-10 4,0E-11 1,0E-10 2,0E-11 arctic 0,0E ,0E fair agreement model-measurements fair agreement with observed time trends

20 Model simulations WATER Model simulation HCB in EU Fresh Water (g/l) Model simulation HCB in Ocean Water (g/l) 8,0E-10 2,0E-11 7,0E-10 1,8E-11 6,0E-10 1,6E-11 1,4E-11 5,0E-10 1,2E-11 4,0E-10 3,0E-10 2,0E-10 t 1/2 = 2 yr 1,0E-11 8,0E-12 6,0E-12 4,0E-12 cont t 1/2 = 12 yr 1,0E-10 2,0E-12 0,0E ,0E fair agreement model-measurements fair agreement with observed time trends

21 Model simulations SOIL Model simulation HCB in EU Soil (g/kg) Model simulation HCB in Background Soil (g/kg) 4,0E-08 6,0E-09 3,5E-08 3,0E-08 2,5E-08 2,0E-08 1,5E-08 1,0E-08 5,0E-09 t 1/2 = 15 yr 5,0E-09 4,0E-09 3,0E-09 2,0E-09 1,0E-09 t 1/2 = 19 yr 0,0E ,0E fair agreement model-measurements fair agreement with observed time trends

22 Model simulation MASS ENVIRONMENT Model simulation Total HCB Mass (tons) Model simulation Total HCB Mass (tons) 2,5E+03 2,5E+03 2,0E+03 2,0E+03 1,5E+03 total mass 1,5E+03 total mass 1,0E+03 5,0E+02 soil 79% 1,0E+03 5,0E+02 cont 69% 0,0E ,0E

23 Persistence in the environment from field data Model simulation Total HCB Mass (tons) Model simulation Total HCB Mass (tons) 2,5E+03 2,5E+02 2,0E+03 2,0E+02 1,5E+03 1,0E+03 5,0E+02 AOC t.yr 1,5E+02 1,0E+02 5,0E+01 AOC 4000 t 0,0E ,0E P ov 0 0 M dt E dt 20 yr

24 Persistence in the environment from field data Model simulation Total HCB Mass (tons) Model simulation Total HCB Mass (tons) 2,5E+03 2,5E+02 2,0E+03 2,0E+02 1,5E+03 1,5E+02 AOC 4000 t 1,0E+03 5,0E+02 AOC t.yr 1,0E+02 5,0E+01 0,0E ,0E M dt P ov 0 0 E dt 20 yr P ov 1 k 0.2 k w k s 9 yr

25 Long-range transport potential? LRTP(PCBs, BDE): - observed half-distance km LRTP ~500 km LRTP x eq u u 2 2k 4k D D / k 500 km u ~0; D ~1500 m 2 /s LRTP(HCB) LRTP x eq u u 2 2k 4k D D / k 1000 km

26 Conclusions Meaningful definitions of P OV and LRTP - average life time of molecules in the environment - average distance traveled by molecules in the environment Can be calculated from substance properties Can be verified with field data

27 Conclusions Meaningful definitions of P OV and LRTP - average life time of molecules in the environment - average distance traveled by molecules in the environment Can be calculated from substance properties Can be verified with field data Ready to go Assign regulatory criteria to P OV and LRTP

28

29 Persistence and long-range transport Various science-proposed definitions P OV - P OV = residence time in environment at steady state 1 mi 1 Pov ov k m k k ov - P OV = recovery time after emission stop i i i i P ov model result Various science-proposed definitions LRTP - LRTP = characteristic travel distance u LRTP L k - LRTP = spatial scale from which 50% is transported LRTP L area P ov model result

30 Persistence and long-range transport P OV and LRTP model-dependent? - Wania and Mackay (1996?) - Fenner et al. (2005) - Klasmeier et al. (2006) - Hollander et al. (2008) Outcome - absolute values of P OV and I are model-dependent - rankings are not Models use own metric - Rank substances - OECD Tool (2005)

31 Persistence and long-range transport Policy questions P OV and LRTP - Conceptually meaningful? Can they serve spirit of conventions? - Can limit values be set? P OV =??? LRTP =??? - Comparison with field data?

32 SimpleBox in MSC-E model comparison Regional SimpleBox model grid - W-Europe - 2 cells Regional, 7.8x10 5 km 2 Continental, 9.6x10 6 km 2 Continental