OECD Environmental Emission Scenarios: Wood Preservatives (PT 8)

Hannu BraunschweilerFinnish Environment Institute (SYKE)

EU course “Exposure scenarios in Risk Assessmentof 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 preservativeProduction of a.s.

Formulation of B.P.

Private/professional use “in-situ”*

Product application (processing)*

Industrial preventive use*

Product application (processing)*

Service life of treated wood (“wood-in-service”)*

Waste treatment(*) Recovery

*) Life-cycle stage covered in the ESD

Potential environmental exposure from wood preservative applications

Emission scenario Soil Ground water

Waste water

Surface water

Air

Preventive applications (before wood-in-service, and professional and amateurs also "in-situ") Automated spraying or dipping, industrial sawmill + + + + + Industrial vacuum pressure + + + + + Double vacuum, industrial joinery + + + Manual or mechanised dipping (large scale joinery) + Dipping (small scale joinery) + + + + + Spraying or injection (indoors) + + Brushing (indoors), amateurs or professionals + Brushing (outdoors), amateurs or professionals + + + + Injection or wrapping (outdoors), professional + + + Termites prevention of foundation + + + + Curative applications (remedial, "in-situ") Spraying or injection (indoors) + + Brushing (indoors), amateurs or professionals + Brushing (outdoors), amateurs or professionals + + + + Fumigation, professional + Injection or wrapping (outdoors), professional + + + Termites prevention of foundation + + + +

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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:1) industrial preventive treatments2) treated wood in service3) 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 ) -> 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:

a) initial assessment = 30 days (TIME1)b) longer assessment period, > 30 days (TIME2)

• Treated wood-in-service:a) initial concentration; immediately after the last application

(e.g. at the end of the application day)b) 30 days; covers the initial leachingc) 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

Structure of the ESDChapter 2 Overview of the treatment types and processes, different

wood preservatives and uses of treated wood

Chapter 3 Background and approaches behind the scenarios and calculations

Chapter 4 Three scenarios for emissions from industrial preventive applications

Chapter 5 Scenarios for emissions during the service life of industrially treated wood, summary of leaching test requirements

Chapter 6 Scenarios for emissions from preventive and curative in-situ treatments, by professionals and/or amateurs, cover treatments and wood-in-service

Chapter 7 Approach for emissions from treated wood as a function of time and taking into account removal processes of substance (e.g. leaching and degradation)

Appendixes General requirements for leaching tests, full description of wood-in-service scenarios, guidance for calculation of fluxes, description of some ground water calculation models, examples of emission calculations, glossary etc.

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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 concernApplication/Scenario

Process(* Storage of treated wood(**

Air Waste water

Surface water

Soil Ground water

Surface water

Automated spraying

+ + (+) + + +

Immersion/ dipping

+ + (+) +(1 +(1 +(1

Pressure processes

+ + (+) +(1 +(1 +(1

(**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 => 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

Storage of treated wood: General equations

Emission during application

Leaching during storage

Concentration in soil

Emission to surface water

FAREAQElocal treatedwoodai

TIMEAREAAREAFLUXQ storageowoodstoragetimestorageleach exp,,

)1(,,runoff

soil

timestorageleachsoil F

MQ

Clocal

runofftimestorageleach

ersurfacewat FTIME

QElocal ,,

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Storage of treated wood scenario: example of input values and outputInput 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

Emission Scenario for automated spraying

No 1: Emission Scenario for anti-sapstain application in automatic spraying (sawmill)

Facility drain

WWTPinfluent

effluent

Run-o

ff

Mix Tank

Spray Box

Drip padwood wood

Stored timber

Rain

recycling

Air driftGenerally roofed

Surface water

estuary

soil

Ground water

Air deposition

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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 => 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

Automated spraying scenario

Parameter/ variable Symbol Unit DefaultsInput:Wood area treated per day AREAwood-treated m2.d-1 2.000 or

20.000Application rate: quantity of a.i.applied per m2 of wood area

Qai kg.m-2 Dossier

Fraction released to facility drain Ffacilitydrain - from pick-list

Fraction released to air Fair - from pick-list

Fraction of spray drift deposition Fdrift - 0.001

Output:Local emission rate to air Elocalair kg.d-1

Local emission rate to facility drain Elocalfacilitydrain kg.d-1

)( driftairaitreatedwoodair FFQAREAElocal

ainfacilitydraitreatedwoodainfacilitydr FQAREAElocal

Emission Scenario for automated dipping

Facility drain

WWTP influent

effluent

soil Dip Tank

Drip pad wood wood

Rain

recycling

Air

( mostly no roof )

Surface water

Ground water

Run- off

Stored timber

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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

Emission Scenario for industrial pressure processes

Facility drain

WWTPinfluent

effluent

Mix Tank

Pressur Vessel Drip padwood wood

Rain

recycling

Air

roof

Surface water

soil

Ground water

Run-

off

(*)

(*) relevantfor oil and organicnot relevantfor salt products

Stored timber

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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

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 (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

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

Timber Cladded House scenario

Parameter/ variable Symbol Unit DefaultsInput:Leachable wood area AREAhouse m2 125

Duration of assessment period TIME1, TIME2 d 1: 302: to be set

Cumulative quantity of a.i. leached out of 1 m2 of treated wood over the assessment period

Q*leach,time kg.m-2 Dossier

Wet soil volume Vsoil m3 0.50

Bulk density of wet soil Fair kgwwt.m3 1700

Output:Cumulative quantity of a.i. leached over the assessment period

Qleach,time kg

Concentration in local soil at the end of assessment period

Clocalsoil,leach,time kg.kgwwt-1

*,, timeleachhousetimeleach QAREAQ

soil

timeleachtimeleachsoil M

QClocal ,

,, soilsoil RHOV

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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 Q*

leach,time1 = 1006 mg/m2

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

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

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)

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

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

Jetty : 1.5 m wide, 8 m long.

Posts : 8, 2 m long, 20 cm diameter, 1 m in water.

Planks : 2.5 cm thick.

Supports : 5 cm thick, 20 cm wide

Primary EnvironmentalCompartment for Emissions

Fresh water : Lake 100 m diameter, 2m deep= 1.6 x107 litres

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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

Jetty in Lake scenario

Parameter/ variable Symbol Unit DefaultsInput:Leachable wood area: planks or poles AREAplanks

AREApoles

m2 16.210.0

Duration of assessment period TIME1, TIME2 d 1: 302: to be set

Cumulative quantity of a.i. leached out of 1 m2 of treated wood over the assessment period

Q*leach,time kg.m-2 Dossier

Water volume Vwater m3 1.6*104

Output:Cumulative quantity of a.i. leached over the assessment period

Qleach,time kg

Concentration in local surface water at the end of assessment period

Clocalwater,leach,time kg.m-3

*,, )( timeleachpolesplankstimeleach QAREAAREAQ

soil

timeleachtimeleachsoil M

QClocal ,

,, waterV

timeleachwater ,,

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.

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)

Wharf scenario

Parameter/ variable Symbol Unit DefaultsInput:Leachable wood area: planks or poles AREAplanks

AREApoles

m2 296911

Duration of assessment period TIME1, TIME2 d 1: 302: to be set

Cumulative quantity of a.i. leached out of 1 m2 of treated wood over the assessment period

Q*leach,time kg.m-2 Dossier: separate value

for poles and planks

Water volume along wharf Vwater m3 1000

Residence time of the seawater TAUseawater d 0.5

Output:Cumulative quantity of a.i. leached over the assessment period

Qleach,time kg

Concentration in local seawater at the end of assessment period

Clocalseawater,leach,time kg.m-3

seawatertimeleach

polestimeleach

plankstimeleach TAUTIME

QAREA

TIMEQ

AREAQ

**,

*,

,

soil

timeleachtimeleachsoil M

QClocal ,

,, waterV

timeleachseawater ,,

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

ARTICLEUSE

CHEMICALUSE

PRODUCTION

FORMULATION

PRIVATE USE(article production)

INDUSTRIAL USE(article production)

ARTICLES

WASTE DISPOSAL- Incineration- Landfilling- Recovery

<< PROCESSING >>

SERVICE LIFE

ARTICLES

Waste remaining in the environment

CHEMICAL PRODUCTIONINTERMEDIATES- non-isolated intermediates- isolated intermediates stored on-site- isolated intermediates with controlled transport

Waste remaining in the

environment

Urban soil

Service life > 1 year EXAMPLE: Chemical X as an additive to a material in shoe

sole.

Accumulation of long-life articles in the society

Steady state at year 2004 Service life of the shoe = 5 year

tonnes / year

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009year

Introduced to the market

= Annual input of X from production = Remaining amount of X in the society year 2,3,4,5 (corrected for reduction due to emission)

annual flow of substance X in molecular form

jgf

Emissions from long life articles

L O C A L S C A L E

URBAN /IND. SOIL

SURFACEWATER

AIR

Incinerationsites

Landfills

C O N T I N E N T A L / R E G I O N A L S C A L E

“Service life”

Accumulated amount of substance X in the society

a b

STP

Annual input from: - “production”- “formulation”- “industrial / professional use”

dc

Explanation of symbols: annual flow of substance X in form of articles / materials

e

i

h

k

Acc. amount of X in “Waste remaining in the environ."

Emission at Steady state when “input” = “output”

…for society: a = [b + c + d + e + f + g + h]…for “waste remaining in the environment”: h = [i + j + k]

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Emissions scenario for long-life articles

Calculations of diffuse emissions at regional / continental scale

1) Estimate service life2) 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)

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Emission equations

kTservice

y

yi,totalkk FQtotte_steadystaQtot_accum

1

1)1(

Simplification when the emission factor is low (<1 %/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