Neclf RA Presentation

Updating UK Risk Assessment Guidance

Dr. Mengfang Chen, Technical Director

Outline

Review of CLEA Development

New Guidance Just Published and Forthcoming

Changes in Standard Land Uses

Changes in Model Algorithms

Results of CLEA Testing

Potential Impact on the Published SGV

USEPA RAGSTier 2 RBCA Toolkit

ASTM E1739Petroleum RBCA

RBCA V1.0ASTM P104

Chemical RBCA

Marked the Start of CLEA

CLEA 97 CLEA2000 CLEA2002 CLEA UK CLAN6/06

1989 1996 1999

1992 1997 2000 2002 2005 2006

Period of Development and Debate, and Continuing

2008

RBCA V2.01

2000

RBCA

CLEAPlant Uptake

Dermal ContactIndoor and Outdoor Vapours

Probabilistic versus Deterministic

Plant UptakeVapour from Surface Soil

Probabilistic versus Deterministic

Plant Uptake

Period of Development Period of Model Improvement and UK Compliance

CLEA 97 CLEA UK CLEA V1.03CLEA 2002

2008

CLEA V1.03

RBCA V1.3ASTM E2081

Chemical RBCA

CLEA

RBCA

History of CLEA Development

CLEA Report (Based on CLAN6/06 Way Forward November 2006)

Consolidation of technical guidance on the CLEA model into a single report focussed on the derivation of SGVs with improved readability and accessibility

Update of the date sets and model algorithms used in the CLEA model based recent scientific literature

Reconsideration of the generic land use scenarios default assumptions used in the CLEA model to derive SGVs including improvements in clarity, internal consistency, and practical usability of the approach.

Updating and Replacing CLR10 and CLEA Briefing Notes 1 to 4

New Guidance JUST Published and Forthcoming

CLEA 97 CLEA UK CLEA V1.03CLEA 2002

New Guidance JUST Published and Forthcoming

Just Published

CLAIRE and CIEH (Replacing CLR7??) – May 2008

CLEA Report (replacing CLR10) – August 2008

CLEA V1.03 beta and Software Handbook – August 2008

TOX Guidance Report (Replacing CLR9) – August 2008

Compilation of Data for Priority Organic Pollutants for the derivation of SGV – November 2008

Forthcoming (Updating TOX and SGV reports) – By March 2009

Arsenic, Cadmium, Chromium, Cyanide, Lead, Mercury, Nickel, and Selenium

Benzene, Toluene, Ethylbenzene, Xylene

Phenol

Dioxins and Dioxin-like Polychlorinated Biphenyls (PCBs);

Polycyclic Aromatic Hydrocarbons (PAHs) – 11 substances

1788549 years

(Age Class 17)Working AdultCommercial

21906 years

Age Class (1 to 6)

Younger ChildAllotments

21906 years

(Age Class 1 to 6)

Younger ChildResidential

Averaging Time (days)

Exposure Duration (years)

Critical Receptor

Standard Land Use

Exposure Duration and Averaging Time


Exposure Frequencies

170230170230-23017 (16 to 65)

365 (65)365 (0)365 (65)365 (0)365365 (65)6 (5 to 6)

365 (65)365 (0)365 (65)365 (0)365365 (65)5 (4 to 5)

365 (130)365 (0)365 (130)365 (0)365365 (130)4 (3 to 4)

365 (130)365 (0)365 (130)365 (0)365365 (130)3 (2 to 3)

365 (130)365 (0)365 (130)365 (0)365365 (130)2 (1 to 2)

365 (25)365 (0)180 (25)180 (0)180180 (25)1 (0 to 1)

days /year

Outdoor Inhalation

Indoor Inhalation

Dermal Outdoor

Dermal Indoor

Homegrown Produce

Soil and Dust IngestionAge Class

(year)


Values in brackets are EF for ALLOTMENT where different from Resident Land use

Building Parameters

0.165 (0.1647)0.04 (0.0423)m2Floor Crack Area

0.150.15mFoundation Thickness

4.43.1PaPressure Difference between Soil and Indoor Air

1.00.5hour-1Air Exchange Rate

6.4 (9.6)4.8mLiving Space Height

42428m2Footprint Area

Commercial (Three-Storey Pre 1970 Office)

Residential (Two-Storey Small Terrace House)

UnitParameters


Consumption Rates and Home Grown Fractions

0.270.04 (0.22)4.264.2611.9611.9611.963.82Tree Fruit

0.60.09 (0.35)0.160.160.540.540.542.23Shrub Fruit

0.40.06 (0.24)1.851.853.963.963.961.83Herbaceous Fruit

0.130.02 (0.12)3.383.385.465.465.4616.03Tuber Vegetables

0.40.06 (0.38)1.771.773.303.303.3010.69Root Vegetables

0.330.05 (0.39)3.743.746.856.856.857.12Green Vegetables

AllotmentResidential5 to 64 to 53 to 42 to 31 to 20 to 1

Home Grown Fractions (HF)

Consumption Rate (CR) (g FW kg-1 BW day-1)Vegetable Type


Key Exposure Parameters

14.80.78.3501607017 (16 to 65)

12.2 (24.9)1 (3)1910011019.76 (5 to 6)

12.2 (21.3)1 (3)1910010016.95 (4 to 5)

12.2 (19.1)1 (3)231009015.14 (3 to 4)

12.7 (20.7)1 (3)231009012.73 (2 to 3)

13.3 (18.8)1 (3)23100809.82 (1 to 2)

8.5 (10.3)1 (3)23100705.61 (0 to 1)

m3/dayHour d-1Hour d-1mg/dcmkg

Daily Inhalation Rate (Vinh)

Outdoor Site Occupancy Period (Tsite)

Indoor Site Occupancy Period (Tsite)

Soil and Dust

Ingestion Rate

Body Height (H)

Body Weight (BW)

Age Class (year)



Parameters Affecting Inhalation of Indoor and Outdoor Dust

1000.70.8120Commercial

--0.5120Allotment

600.70.752400Residential

µg m-3g g-1-g.m-2.s-1/kg.m-3

Soil Loading Factor (SL)

Transport Factor (TL)

Fraction of Vegetative and Buildings (V)

Air Dispersion Coefficient (Q/C)Land Use

Q/C default values were taken from Newcastle

representing areas of 0.01, 0.5 and 2 Ha

Respectively for residential, allotment and

commercial land uses

TL and SL used to calculate

intake rate for inhalation of indoor dust

Soil Parameters

7.54E-080.35090.12217.36E-030.070.540.240.31.18Sand

3.05E-080.32010.06893.56E-030.120.530.330.21.21Sandy Loam

1.05E-080.30780.03751.58E-030.180.580.4400.141Silt Loam

1.83E-080.30980.0562.37E-030.150.530.370.161.2Sandy Clay Loam

1.08E-080.30390.04371.51E-030.190.560.420.141.14Clay Loam

7.28E-090.30720.02911.17E-030.210.580.50.11Silty Clay Loam

7.18E-090.31550.05411.17E-030.260.630.510.120.94Silty Clay

6.58E-090.29720.03859.93E-040.240.590.470.121.07Clay

dimensionlesscm3 cm-3cm2

mαcm s-1cm3 cm-3

TotalWaterAirg cm-3

Effective Air Permeability

van GenuchtenSaturated Hydraulic

Conductivity

Residual Water Content

PorosityBulk

DensitySoil Type


Effective air permeability is calculated using Equations A4 to A7 in Appendix A of the CLEA Report

New USEPA Method to Calculate Total Skin Surface Area 51456.042246.00235.0 BWHSA ××=

476 (411)476 (411)0.080.081.7851607016 to 65

873 (792)688 (642)0.330.260.79411019.75 to 6

822 (790)657 (632)0.350.280.70410016.94 to 5

742 (700)593 (560)0.350.280.6369015.13 to 4

620 (582)485 (454)0.320.250.5829012.72 to 3

533 (490)420 (386)0.330.260.484809.81 to 2

366 (361)297 (293)0.320.260.343705.60 to 1

cm2cm2--

IndoorOutdoorIndoorOutdoorm2cmkg

Exposed Skin (SEin

skin)Exposed Skin

(SEoutskin)

Max Fraction of Exposed Skin (Φexp)

Total Skin Surface Area

(SA)

Body Height

(H)

Body Weight

(W)Age Class (year)


90BW

7BW)(4AT +

+×=

Preparation Factor (PF) – Soil Ingestion Attached to Vegetables


0.60.0010.157Tree Fruit

0.60.0010.166Shrub Fruit

0.60.0010.058Herbaceous Fruit

10.0010.21Tuber Vegetables

10.0010.103Root Vegetables

0.20.0010.096Green Vegetables

-(g g-1 FW)(g DW plant g-1 FW plant)

Preparation Factor (PF)

Soil Loading (SL)

DW Conversion Factors (DW)

Vegetable Type

( )∑=

×××××=TypeVegofNo

iiiiiii

soil

SLPFDWHFBWCRC

IR ___

1


New Routine (USEPA Q/C) for Inhalation of Outdoor Vapours

41031536000

4

/

10 ××

×××

××=ssw

ambeff

wind

s

K

HD

CQVF

ρτπρFor Surface Soil (10 cm)

USEPA 1996 Q/C Model

For Subsurface Soil (>10 cm)

ASTM 2000 (E2081)aw

sw

eff

wind

KK

D

gkgmcmcmmCQVF

××××

+

=−−−− 13322

10001

1000000100001

/1

1

GQRA

DQRA

τρ

××=wind

ss

CQ

dVF

/Mass Balance Approach

Changes for Inhalation of Indoor Vapours

GQRA

DQRA

Case A (τd > ED)

Case B (τd < ED)

Mass Balance

65 (including 15 cm foundation thickness)cmDepth to Top of Source

30050cm3 s-1Soil Gas Ingress Rate

Commercial (Post 1970 Office + Sandy Soil)

Residential (Detached House + Sandy Soil)

UnitParameters


33610 −××

××= mcmQ

AdVF

b

bss

τρ

( )( )βϕτβτ

ρ −+

×

××= 22

s

T

b

bss

d

L

Q

AdVF

ϕ

ββτ

2

2

2

−

+

= T

s

d

L

d

Calculating time for source depletion


Complete New Plant Uptake Algorithms

Beetroot, carrot, cassava, garlic, ginger, Jerusalem artichoke, leek, onion, parsnips, radish, rhubarb, salsify, swede, sweet potato, turnips and yam

Root Vegetables

Aubergine, courgettes, cucumber, marrow, pumpkin, strawberries and tomatoes Herbaceous Fruit

PotatoesTuber Vegetables

Apples, apricot, cherries, peaches, pears and plumsTree Fruit

Bilberries, blackberries, cranberries, gooseberries, loganberries, mulberries, physalis, raspberries, blackcurrants, redcurrants and white currants

Shrub Fruit

Beans (broad, French, green and runner beans), cabbage (red, white, greens and kale), cauliflower, lettuce, spinach, peas (garden and mange tout), stem vegetables (broccoli, celery, asparagus), okra, global artichokes, Chinese leaves, endives, chicory, chard, dandelion, watercress and fresh herbs (basil, coriander, tarragon, sage, parsley and mint)

Green Vegetables

CROPS INCLUDEDPRODUCE GROUP

35 Additional Plant Properties Introduced


Organic Compounds

Inorganic Compounds




DescriptionsUnitSymbol

Chemical Concentration in the Woody Stemmg cm-3 per mg g-1Cstem

Chemical Concentration in Xylem Sapmg cm-3 per mg g-1Cxy

Wood Water Partition Coefficientsmg g-1 dw wood per mg cm-3 waterKwood

Rate of Chemical Flux into PotatoHour-1k1

Rate of Chemical Flux Out of PotatoHour-1k2

Diffusion Coefficients in Waterm2 s-1Dw

Equilibrium Partition Coefficient between Potato and Watercm3 g-1 fwKpw

Carbonhydrate-Water Partition Coefficientscm3 g-1 fwKch

Equilibrium Partition Coefficient between Root and Water cm3 g-1 fwKrw

Soil Leachate Partition Factorkg/lKsw

Plant Media Transfer Coefficients and Concentrations

Introduction of New Cross-Media Coefficients and Concentrations


Inorganic Compounds


intfKCR

dws

×+

=ρθ

δ

0.5Tree Fruit

0.5Shrub Fruit

0.5Herbaceous Fruit

0.5Tuber Vegetables

0.5Root Vegetables

0.5Green Vegetables

Fraction of chemicals in root system reaching edible plant plants (fint)

Vegetable Type

50Selenium

5Mercury

5Chromium

5Cadmium

5Arsenic

δ

Soil to Plant Availability CorrectionContaminant

Complete New Plant Uptake Algorithms Organic Compounds – Green Vegetable


( )

+

×+= −−−

ococsw

sKKGreen fK

CF owow

ρθρ

)10784.0(82.010 44.2/)78.1(log434.005.2log95.0 2

Only Routine Retained from CLR10 (CLEA2002)

ρθρθ aococw

swHfK

K++=CLEA UK

Complete New Plant Uptake Algorithms Organic Compounds – Root Vegetable


( )( ) Vkk

KQ

KQCF

pmgrw

dRoot

ρ++= /

bow

pprw aK

LWK

ρρ+=

Correction Coefficients for Roots-b

Density Correction Factor between Water and Octanol-a

Root Lipid Contentg g-1L

Root Water Contentg g-1W

First Order Metabolism Rate Constantd-1km

First Order Growth Rate Constantd-1kg

Root Volumecm3V

Plant Root Densityg fw/cm3ρp

Transpiration Stream Flow Ratecm3 d-1Q


Complete New Plant Uptake Algorithms Organic Compounds – Tuber Vegetable


ρθρθ aococw

swHfK

K++=

bow

pchch

ppw aK

LKf

WK

ρρ++= )(

=

sw

pw

K

Kkk 21

2

3/7

2

)/(360023

R

K

WD

Kpw

pw

=

ρ

gTuber kk

kCF

+=

2

1


Radius of PotatomR

Exponential Rate of Growth of Potatohour-1kg

Correction Coefficients for Roots-b

Density Correction Factor between Water and Octanol-a

Lipid Content of Potatog g-1L

Fraction of Carbonhydrates in the Potato-Fch

Plant Tuber Densityg/cm3ρp

Water Content of Potatog g-1W

Complete New Plant Uptake Algorithms Organic Compounds – Tree Fruit


owwood KLogK log632.027.0 +−= 58.2

)5.2(log 2

756.0−−

=

owK

sw

sxy e

K

CC

gewood

xy

stem

kkMK

QM

QC

C++

=

s

fwood

stemfruitfruitf

TreeFruit C

MKC

DMQM

CF

/)(

=


Dry Matter Content of Fruitg g-1DMfruit

Water Flow Rate per Unit of Mass of Fruitcm3 g-1 fwQfruit

Mass of Fruitg fwMf

Rate of Dilution due to Wood Growthyear-1kg

Rate of Chemical Metabolismyear-1ke

Mass of Woody Stemg dwM

Transpiration Stream Flow Ratecm3 d-1Q

Summary of CLEA Testing


ssw

ambeff

wind

s

K

HD

CQVF

ρτπρ

××

×××

×=

31536000

4

/101

Equation 9.6

Indoor Dust

Equation 10.2

Outdoor Vapour

( )

××

××+×

×= −

241000

1 1 siteinhss

TVDLTFCKgg

PEFCIR

( ) 1100024

1 −×

××

××+

×= Kgg

TVDLTFC

PEFCIR site

inhss

ssw

ambeff

wind

s

K

HD

CQVF

ρτπρ

××

×××

=31536000

4

/

Way Forward

Comparison of RBCA V2 and CLEA V1.03 beta

Thank you for your attention

Neclf RA Presentation

Technology

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