OECD Environmental Emission Scenarios: Wood Preservatives ( PT 8)

1. OECD Environmental Emission Scenarios: Wood Preservatives (PT 8) Hannu Braunschweiler Finnish Environment Institute (SYKE) EU course “Exposure scenarios in Risk Assessment of Wood Preservatives and Rodenticides” 9-10 October 2003, ECB, Ispra

2. OECD Emission Scenario Document for Wood Preservatives • Developed in the OECD Expert Group on the basis of a workshop, published by OECD in March 2003 • OECD Series on Emission Scenario Documents No. 2 • Parts 1-4 • Some of the scenarios have been tested in the EUBEES-2 project, primarily with regard to usability • Adopted at the 14th EU Competent Authority meeting June 2003: • “CAs recommend its use with the note that the ESD is a living document.” • “The ESD can be revised in the light of new knowledge, experience gained in its application, and data from real measurements made by industry.” • The ESD is available also through http://ecb.jrc.it/biocides/

3. Life-cycle of a wood preservative Production of a.s. *) Life-cycle stage covered in the ESD Formulation of B.P. Private/professional use “in-situ”* Industrial preventive use* Product application (processing)* Product application (processing)* Service life of treated wood (“wood-in-service”)* Waste treatment(*) Recovery

4. Potential environmental exposure from wood preservative applications

5. Detailed scenarios in the ESD • Focus of the emission scenarios • Estimation of local emissions to primary receiving environmental compartments and local environmental concentrations within them from: • industrial preventive treatments • treated wood in service • in situ treatments (curative and preventive) • Two options for calculation of Clocal • without removal processes of the substance (Ch. 4-6) • withremoval processes in the receiving compartment (e.g. due to degradation, volatilisation, leaching to groundwater ) -> modified formulas in Chapter 7

6. Time scales of the scenarios • Local emissions and concentrations from treated wood • Storage of industrially treated wood: • initialassessment = 30 days (TIME1) • longer assessment period,> 30 days (TIME2) • Treated wood-in-service: • initial concentration; immediately after the last application (e.g. at the end of the application day) • 30 days; covers the initial leaching • during the rest of the service life (> 30 days). Depending on the characteristics of the active ingredients and the service life of treated commodities, time periods of several years of service life can be used

7. Structure of the ESD

8. Industrial preventive treatment • 3 scenarios • Automated spraying processes • Dipping/immersion processes • Pressure processes • For all 3 scenarios, emissions take place during • Treatment process • Post-treatment conditioning • Storage of treated wood prior to shipment

9. Preventive industrial processes: compartments of concern (*No emissions to soil (**No emissions to air and wastewater (1 Not relevant for joineries

10. Preventive industrial processes/ storage of treated wood: assumptions • Realistic worst-case: • storage area is uncovered and unpaved • default values for the parameterAREAwood-treated and emission factors (F) • default value for rainfall 3 rain events, 60 min each, every third day, with a precipitation of 4 mm.h-1 => corresponds to 1460 mm.y-1;the leaching test should mimic this rainfall pattern • Storage begins after post-treatment conditioning • Emissions are cumulative during the storage time and also from the application phases • Degradation processes should be taken into account

11. Storage of treated wood: General equations • Emission during application • Leaching during storage • Concentration in soil • Emission to surface water

12. Input data *Qai = 15 g/m2 #AREAwood-treated = 2000 m2/d #F = 0.03 *$FLUXstorage = 128 mg/m2/d #AREAwood-expo = 11 m2/m2 #AREA storage = 79 m2 #TIME1 = 30 d #Msoil = 13430 kg ww #F runoff = 0.5 Results Elocal = 0.9 kg/d Qleach,storage,time = 3.34 kg Clocalsoil = 124 mg/kg ww Elocalsurfacewater = 0.056 kg/d Storage of treated wood scenario: example of input values and output *Value to be set # Default value $ This is the leaching rate

13. Emission Scenario for automated spraying

14. Automated spraying scenario: assumptions • Realistic worst-case: • emissions to air occur directly due to spray drift / evaporation from the spray box and from the treated wood after it • cemented floors, run-off recycled; unintentional spills, floor & equipment cleaning, washing waters etc. go to facility drain => to the sewage treatment plant • default emission factors (F) depend on water solubility and vapour pressure (given as pick-lists) • All industrial spraying applications covered, 2 plant sizes • Emission to surface water only via dry deposition; not yet quantified • Emissions are cumulative from the application phases and also during the storage time

15. Automated spraying scenario

16. Emission Scenario for automated dipping

17. Automated dipping scenario: assumptions and calculations • All industrial and professional dipping / immersion applications covered: sawmills and joinery / carpentry • Assumptions and calculations are much the same as for the spraying scenario; the differences are: • no spray drift to air: emissions to air occur due to evaporation from the dipping bath, co-distillation with solvent and from saw dust / dried salts • calculations based on volume of treated wood (100 m3.d-1) instead of area; conversion formulas provided • No direct emission to surface water from the process, only from storage

18. Emission Scenario for industrial pressure processes

19. Industrial pressure processes scenario: assumptions and calculations • All industrial pressure applications covered with 2 plant volumes • vacuum pressure: wood volume treated per day 30 m3.d-1 • double-vacuum & low pressure: daily wood volume 15 m3.d-1 • Assumptions and calculations are much the same as for the spraying scenario; the differences are: • no spray drift to air: emissions to air occur due e.g. releases at cease of vacuum, evaporation losses, aerosol air drifts and from saw dust / dried salts • calculations based on volume of treated wood (see above) instead of area • No direct emission to surface water from the process

20. Use classes of treated wood, the emission scenarios & relevant compartments ( )

21. Scenarios for treated wood in service • 4 relevant use classes with 10 detailed scenarios • UC3 Wood not covered and not in contact with soil: 4 scenarios • UC4a Wood in contact with soil: 2 scenarios • UC4b Wood in contact with fresh water: 2 scenarios • UC5 Wood in contact with salt water: 1 scenario • House scenario represents a worst case compared to the fence and noise barrier because of the highest wood to soil ratio • Recommended to use the house scenario preferentially • Use the fence scenario as a further option • Noise barrier scenario resembles the fence but includes a emission route to a sewage treatment plant (70% of emission)

22. General assumptions in thewood-in-service scenarios • All scenarios require that leaching rate (FLUX [kg/m2/d]) be established, e.g. from leaching tests • Cumulative amount leached over certain time (Q*leach,time [kg/m2]) is estimated from FLUX • General equations used for emissions during storage apply also for the scenarios of treated wood-in-service • Default values given for leachable treated wood area and volumes of receiving compartments • The primary receiving environmental compartment is considered to be soil or water (including STP) • Emissions to the air are considered negligible from environmental point of view

23. Use class 3: Emission Scenario for Timber Cladded House (with receiving soil compartment)

24. Timber Cladded House: assumptions • The primary receiving environmental compartment is considered to be soil via rain run-off • Leaching rates to be used should be from a test with wood in direct contact with water • Summary of test requirements is in Section 5.3.2.1 and requirements for the design of such a leaching test is given in Appendix 1 • Emissions are cumulative over the assessment period, therefore Clocal represents the concentration at the end of the assessment time period • Emitted quantity calculated may be fed into groundwater models

25. Timber Cladded House scenario

26. Timber Cladded House: example of input values and results Input data • AREAhouse = 125 m2 • Soil “width” = 0.1 m (default) • Soil depth = 0.1 m (default) • Msoil = 850 kgww • TIME1 = 30 d • Q*leach,time1 = 1006 mg/m2 Results • Qleach,time1 = 0.13 kg (over 30 d) • Clocalsoil,leach,time1 = 591 mg/kgww (D = 0.025 m) • Clocalsoil,leach,time1 = 147 mg/kgww (D = 0.1 m) • Clocalsoil,leach,time1 = 28 mg/kgww (D = 0.5 m)

27. Use class 3: Emission Scenario for noise barrier (with receiving environmental compartments)

28. Use class 3: Emission Scenario for garden fence (with receiving soil compartment)

29. Use class 4a: Emission Scenario for Transmission Pole (with receiving soil compartment)

30. Transmission Pole scenario: assumptions and calculations • Recommended to use the transmission pole scenario preferentially • Use the fence post scenario as a further option if e.g. required due to preservative type • The primary receiving environmental compartment is soil which has cumulative emissions from: • rain run-off from above soil part of the pole • permanent contact with the soil water phase for below ground part • Assumptions and calculations are much the same as for the cladded house scenario; main differences are: • separate above and below soil wood areas (5.5 and 1.6 m2) • leaching rates to be used should be from a test with wood in direct contact with water or in contact with soil (for below ground part only)

31. Use class 4a: Emission Scenario for fence post (with receiving soil compartment)

32. Use class 4b: Emission Scenario for Jetty in Lake (with receiving water compartment)

33. Jetty in Lake scenario: assumptions • For Use Class 4b, two scenarios available: jetty in a lake and a sheet piling in a small stream or waterway • The jetty scenario is a worst case with respect to the higher wood surface area • The sheet pilings scenario represents a worst case because of the wood being exposed mainly under water • The primary receiving environmental compartment is a circular pond which has cumulative emissions from: • planks exposed to rain (usually treated for Use Class 3) • poles all in permanent contact with water (treated for Use Class 4b) • Leaching rates to be used should be from a test with wood in direct contact with water • General assumptions similar to the house scenario

34. Jetty in Lake scenario

35. Use class 4b: Emission Scenario for sheet pilings in a small streaming waterway • There are 5 poles on both sides per meter waterway length. • The waterway is 1 km long, 1.5 m deep and 5 m wide, with the residence time of 20 days.

36. Use class 5Emission Scenario for Harbour Wharf • The wharf is 100 m long with walling and kerbing extending the full length. • The walling is doubled at the front and back of the fender piling. • Piles with associated rubbing strips are spaced at 5 m intervals. • The receiving compartment is the seawater at up to 5 m distance from the wharf.

37. Wharf scenario: assumptions • The primary receiving environmental compartment is salt water in an intermediate-sized wharf • Seawater has cumulative emissions from: • planks exposed to rain (usually treated for Use Class 3) • poles all in permanent contact with seawater (treated for Use Class 5) • The contact time of wood with the water and therefore the concentration is determined by the water residence time • Leaching rates to be used should from a test with wood in direct contact with seawater (submerged poles) and with de-ionised water (planks above water)

38. Wharf scenario

39. Potential exposure of environmental compartments from professional and amateurin-situ treatmentsChapter 6

40. Accounting for removal processes in water and soil • Removal processes in the receiving compartment are degradation, volatilisation, leaching to groundwater (for soil) or sedimentation (in surface water) • In a first tier estimation these can be ignored (Ch. 4-6) • For a second tier the removal processes can be estimated e.g. according to TGD and taken into account in the estimation of the concentrations in water or soil • Guidance on how to calculate emissions from treated wood as a function of time and taking into account removal processes of the substance is given in Chapter 7 • The longer time span proposed: 1 year or longer (up to 10 yr)

41. General remarks on the ESD • Guidance given on appropriate leaching tests for treated wood and especially how to use different kind of leaching test results • Some guidance given for calculation of the emissions from treated wood that may reach groundwater in soil • Applicability of PEARL and PELMO groundwater models discussed: regarding scenarios for treated wood-in-service and storage • In the scenario description Tables, the input and output data are divided into three groups: • A: “data Set” data to be supplied by the notifier; no default value is set. Note: Symbol “S” used for this group in the EU ESDs & spreadsheets • D “Default” parameter has a standard value (most defaults can be changed by the user); • O “Output” parameter is the output from a calculation (most output parameters can be overwritten by the user with alternative data);

42. Conclusions on the OECD ESD • ESD covers use scenarios and environmental compartments of (presumed) highest concern • Based on empirical data & default values but has not been validated; only the applicability of the equations has been tested • Can be used when no other overriding data are available (c.f. TGD) • Specific data on use pattern and emission rate should be used by applicants whenever possible • Results from emission estimates should feed into exposure assessment in accordance with the Technical Guidance Document on risk assessment • combined with some generic emission estimates according to the TGD

43. Revised TGD: relevant exposure assessment issues • More complete life cycle assessment • Release estimation • emissions from long-life articles • emissions from waste disposal including recovery • Unintentional uses: calculation of background concentrations

45. Accumulation of long-life articles in the society • Service life > 1 year • EXAMPLE: Chemical X as an additive to a material in shoe sole.

47. Emissions scenario for long-life articles • Calculations of diffuse emissions at regional / continental scale 1) Estimate service life 2) Estimate emission factors (F) 3) Calculate accumulation 4) Calculate annual release • F < 1%/year  simplification • Local scale: for the municipal STP • Indoor emissions • Outdoor emissions via storm water (IC 5, Personal/Domestic)

48. Emission equations Simplification when the emission factor is low (<1 %/year): Qtot-accum_steady statek = Qtotk * Tservice

49. “Unintentional sources” / Cumulative effects (TGD, Part II, App. XIII) • The rapporteur should list other sources which can give rise to exposure by the substance being assessed • Evaluation report should include available information on these sources: other PTs, non-biocidal uses • For biocides, only sources which include substances of natural origin or releases from other biocidal uses should be taken into account as “cumulative effects” in the risk assessment • Cumulative effects are to be taken into account in the PECregional which provides the background concentration to be incorporated in the PEClocal • PECregional to be calculated with EUSES using generic assumptions