Exposure Assessment &Exposure Scenarios

Dinant KroeseChemical Safety assessment scheme

From REACH Guidance on information
requirements and CSA – Part DCONTENTS
1.

What are Exposure Scenarios

2.

Tiered approach: models and measured data

3.

Experience4.

Developments

What is an Exposure Scenario?
Conditions and risk management measures representing control ofrisk for manufacture and use of a substance• Documentation in the CSR• Input information for exposure estimates• Instructive guidance for preparation makers, e.g. paints,lubricants, adhesives, cleaners
Conditions and risk management measures representing control ofrisk for manufacture and use of a preparation• Instructive guidance for users of preparations in industry andthe professional sector

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Generic Exposure Scenarios

TNO Quality of Life, October2008

What is a Generic Exposure Scenario?
(Partial) description of conditions and risk management measures
representing control of risk for manufacture and use of a numberof substances or preparations (in a number of situations)• An ES valid for several substances or preparations• Basis for individual ES for separate substances orpreparations

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Generic Exposure ScenariosTNO Quality of Life, October2008

Tiered approach for Exposure Scenarios
Tier 1:tool / simple, broadly applicable and conservative
Tier 2:
tool /- more differentiation in situations compared to Tier 1 tools- more Risk Management Measures included- more input data needed- more specific, possibly less conservative assessment
or measured data (with contextual information)

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Higher Tier Evaluations and Models

TNO Quality of Life, October2008

Tiered approach for Exposure Scenarios
Tier 1:
tools: worker:

ECETOC TRA

consumer: CONSEXPO (simple)
Tier 2:tools: worker:

Stoffenmanager (inhalation)
RISKOFDERM (dermal)

consumer: CONSEXPO (full version)or measured data (with contextual information)

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Higher Tier Evaluations and Models

TNO Quality of Life, October2008

Measured data
• Idealy: focused measurements (often impracticable)• Other options:• Literature search – few with context• Own databases – few scenarios• Choice• Inhalation data STEAMBASE• Dermal data RISKOFDERM• (with limited suppl. literature)Tier 1 model: ECETOC TRA

Process /handlinge.g.
Non/widedispersiveSpraying/not

Substancee.g.
Vapour pressure
Dustiness

Containment/ventilatione.g.
Open/closed
LEV/general
ventilation

Duration /amountExposure

e.g.
Range
Distribution• Limited number of parameters• Rough categorisation, few options• Some unclear terminology or unclear differences between options• Meant for full shift exposure

Higher tier models• Existing models (mentioned in Guidance)• Stoffenmanager (inhalation only)• RISKOFDERM (dermal only)• CONSEXPO (all routes)• Model in development• Advanced REACH Tool (first inhalation, later also dermal)• Possibly highly specific models• Spray application• Ad hoc models

10Higher Tier Evaluations and Models

TNO Quality of Life, October2008

Stoffenmanager example
Substance info

Physical state

LiquidVapour pressure

3 Pa

Percentage in product

100%Tasks (liquids)
Measuring doses with a dose-measuring device

Task

Mixing/diluting of liquids by stirring
Manually drawing off or pouring of a productHandling of heavily contaminated tools/objects or packages

RMMs + OCs

Exposure

Other sourcesin room

Yes

YesNoNo

Emission control

General ventilation

Containment of the source with local exhaust ventilationNone

Containment of the source

Room size

Mechanical or naturalLocal exhaust ventilation (LEV)< 100 m3

Spray cabin

Use of a product that limits the emission

100 -1000 m3

No local controls> 1000 m3

Immission control
Worker in cabin + fresh air
Worker in cabin no fresh air

11Worker < 1mfrom source

not in cabin
Stoffenmanager: worker exposure Worker
assessment

OutsideCleaning OK?

Maintenance OK?

Yes

Yes

NoNoExposure: GM = 0.17
90% = 2.55 mg/m3
TNO Quality of Life, October 2008

RISKOFDERM example
DEO Unit
Filling, Mixing, Loading

DEO UnitWiping
Dispersion with a hand-held tool

ContactSpraying

Contact frequency

Contact intensity

Immersion

Rare (once/scenario)

Light

Mechanical treatment

More than rare

More than light

Automation

Aerosol formation(Semi) automatedManualSignificant
Not significant

Substance
LiquidSubstance

Solid – low/moderately dusty
Ventilation

OCs + RMMs

Solid - high dusty

Poor
Use rate (L/min)
Normal or good
4Exposure

Percentile?
9012

Higher Tier Evaluations and Models

Exposure: GM = 35 µg/cm2/min
90% = 303 µg/cm2/min
TNO Quality of Life, October2008

3. Experience•••Tier 1 models are very rough• Easy and useful for first check• Difficult to show control of risk for more hazardous
substances
Existing measured data difficult to interpret• Unexplained unexpected high values• Variation between apparently similar exposure groups
Inputs for models (both Tier 1 and further) often difficult
to choose• E.g. ‘scenario’ in ECETOC TRA• E.g. ‘use rate’ in RISKOFDERM

3. Experience (2)General approach•

Try to find a suitable GES•
Adapt this to your chemical, with possibly further smallmodifications•

Otherwise take Tier 1 estimations•
Do reality check whether existing data do not facilitate a change•

In case no control of risk… try further Tier models or measured dataSummary• Many approaches based on knowledge of present OC + RMM• ECETOC TRA based estimates easy to make• What if Tier 1 assessments do not show control of risk?
• How to account for within sector variation?
• More complex situations that do not fit Tier 1 assessments
 Build up GES from specific to generic Use measured data or further Tier models• Generic Exposure Scenarios possible for substance groups• Ranges of physico-chemical characteristics• Ranges of DNELs
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Generic Exposure Scenarios

TNO Quality of Life, October2008

4. Developments in Exposure Assessments• New versions of ECETOC TRA expected in April• Worker part
• Take account of all Process Categories• Differentiation between industrial and professional• Consumer part
• Simplified Tier 1 version of CONSEXPO• Broad product categories with some subcategories• Acceptance of changes for REACH Guidance through
Guidance update• Advanced REACH Tool for Tier 1 (inhalation) expected end 2009
• Model based on source-to-target concept• Bayesian combination with measured data

Development of ART• ART = Advanced REACH Tool
• Consortium: IOM, HSL, BAuA, AMI, IRAS & TNO• CEFIC/Eurometaux sponsored• May be made company specific
Deterministic model,incl. Monte CarlomoduleSimilarity module to selectdata for risk assessment

Bayesian process tocombine data and model
output0

Goal:
A tier 2 tool for refined worker
exposure assessment

Exposure database, with
contextual information

Exposure estimates forrisk assessment

Development of hazard assessment
DNELtarget

11.0 mg/m3

Based on AF of 2 for read across45.1 mg/m3

Based on own testing data

22.2 mg/m3

source22.1 mg/m3

14.8 mg/m3

Instead of deterministic
a probabilistic
derivation of a DNEL
to allow a fullprobabilistic RC

4. Developments in Exposure Assessments (2)Free web based CSA tool for registrants-Extracts relevant information from IUCLID5 (DNELs, R-phrases, physchem data..);-Asks for exposure determinants input from Userto:

Simple Version: 01/12/09
Extended Version: 01/04/10-Give a 1e tier exposure assessment (with ECETOC TRA model, for worker & cons)-Calculates RCR for all relevant scenarios and combinations of applicable routes-If ‘control of risks’:- provides ‘+’ descriptions for SDS+
- documents conclusion in CSR-If ‘no control of risks’: - indicates that User should perform 2nd tier assessment- asks for result 2nd tier to conclude yes/no ‘control of risks’ES Modifier & chain communication• ES Modifier: An IT-tool for formulators• With the ES modifier a user may:
• Develop an ES for mixtures• Scaling: check OCs and RMMs in the ES received• Models included:• ECETOC TRA, EUSES, ERC’s, StoffenManager,RiskOfDerm, COSHH-BAUA• CEFIC and DUCC on board• Include in mapping

Thank you for your attention!