OECD Environmental Emission Scenarios: Wood Preservatives PT 8

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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

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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/

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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
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Potential environmental exposure from wood
preservative applications
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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)
• with removal processes in the receiving
  compartment (e.g. due to degradation,
  volatilisation, leaching to groundwater ) -gt
  modified formulas in Chapter 7

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Time scales of the scenarios

• Local emissions and concentrations from treated
  wood
• Storage of industrially treated wood
• initial assessment 30 days (TIME1)
• longer assessment period, gt 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 (gt 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

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Structure of the ESD
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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

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Preventive industrial processes compartments of
concern
(No emissions to air and wastewater (1 Not
relevant for joineries
(No emissions to soil
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Preventive industrial processes/ storage of
treated wood assumptions

• Realistic worst-case
• storage area is uncovered and unpaved
• default values for the parameter AREAwood-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 gt 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

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Storage of treated wood General equations

• Emission during application
• Leaching during storage
• Concentration in soil
• Emission to surface water

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Storage of treated wood scenario example of
input values and output

• 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

Value to be set Default value This
is the leaching rate
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Emission Scenario for automated spraying
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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 gt 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

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Automated spraying scenario
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Emission Scenario for automated dipping
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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

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Emission Scenario for industrial pressure
processes
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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

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

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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
  (Qleach,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

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

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Timber Cladded House scenario
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Timber Cladded House example of input values and
results

• 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)

• Input data
• AREAhouse 125 m2
• Soil width 0.1 m (default)
• Soil depth 0.1 m (default)
• Msoil 850 kgww
• TIME1 30 d
• Qleach,time1 1006 mg/m2

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Use class 3 Emission Scenario for noise barrier
(with receiving environmental compartments)
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Use class 3 Emission Scenario for garden fence
(with receiving soil compartment)
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Use class 4a Emission Scenario for Transmission
Pole (with receiving soil compartment)
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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)

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Use class 4a Emission Scenario for fence post
(with receiving soil compartment)
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Use class 4b Emission Scenario for Jetty in Lake
(with receiving water compartment)
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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

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Jetty in Lake scenario
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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.

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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.

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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)

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Wharf scenario
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Potential exposure of environmental compartments
from professional and amateur in-situ
treatments Chapter 6
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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)

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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)

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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

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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

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Accumulation of long-life articles in the society

• Service life gt 1 year
• EXAMPLE Chemical X as an additive to a material
  in shoe sole.

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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 lt 1/year ? simplification
• Local scale for the municipal STP
• Indoor emissions
• Outdoor emissions via storm water
  (IC 5, Personal/Domestic)

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Emission equations
Simplification when the emission factor is low
(lt1 /year)
Qtot-accum_steady statek Qtotk Tservice
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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