Literature review: • Reviewed dermal absorption journal articles and model documentation. • Goal: Identify substance properties and exposure scenarios controlling dermal absorption.

Model development: • Developed framework to calculate dermal uptake of substances from a particular product called Product Intake Fraction (PiF), which parallels the existing LCA matrix framework. • Developed framework to calculate direct impacts of substances from three products: a pacifier, hand soap, and shampoo. • Defined each product’s functional unit as 1 day of normal use.

Data collection:Direct exposure - • Compiled product composition data from ConsExpo (RIVM 2010), an exposure assessment model. • Compiled substance physicochemical properties from USEtox (Rosenbaum et al. 2008), a consensus LCA model. • Used dose response data and severity factors from IMPACT 2002+ (Jolliet et al. 2003). • Measured parameters for: pacifier (mass of mouthing piece), hand soap (mass of soap and water to wash hands), and shampoo (mass of shampoo and water to wash hair).

Indirect exposure - • Compiled primary and secondary PM2.5 emission rates from IMPACT 2002+ (for pacifier). • Used PM2.5 characterization factor data from Humbert et al. (2011) (for pacifier). • Adapted pre-calculated indirect life cycle impact results from Koehler et al. (2009) (for soap and shampoo).

Analysis: • Compared skin permeability coefficient equations. • Calculated direct product impacts based on newly developed framework. • Calculated indirect product life cycle impacts based on model development and conversion data from IMPACT 2002+. • Compared direct vs. indirect impact for each product.

METHODS

Motivation: Life Cycle Assessment (LCA) is a tool to evaluate the environmental impact (to human health and ecosystems) of a product throughout its life cycle stages. Current LCA approaches calculate exposure through environmental emissions leading to inhalation and ingestion, BUT dermal contact, e.g., from consumer products, is not covered. Existing risk models estimate dose from dermally applied products, but there is little information regarding product impacts on human health.

Methods: Equations linking chemical properties to dermal uptake to human health impacts of a chemical substance from two product types were developed based on a literature review and a comparison of skin permeability models. Potential dermal uptake of several substances in three products was calculated. In addition, indirect impacts from life cycle emissions were calculated.Results: Direct impact from the products was of the same magnitude as or higher than indirect life cycle impacts. The development of this approach and these results are the first advancement towards introducing dermal exposure into life cycle assessment.

METHODSProducts & Substances Used inData Collection & Analysis

Dermal Exposure for Life Cycle Impact Assessment Susie Chung1, Andrew Henderson2, Shanna Shaked2, Professor Olivier Jolliet2

(1) U. of Michigan, Dept. of Civil & Environmental Engineering, (2) U. of Michigan, School of Public Health,Dept. of Environmental Health Sciences ABSTRACT

RESULTS: Skin Permeability Models

• Developed equation for the Product Intake Fraction (PiF), the fraction of a substance dermally absorbed. Important variables: leach rate and skin permeability coefficient (Kp).

RESULTS: Impact• A method to calculate direct impact for a pacifier, hand soap, and shampoo was developed.• To calculate dose response for direct impacts, ED50 values were required. These were extrapolated from oral LD50s, except for Limonene’s value, which was available in USEtox (Rosenbaum et al. 2008).

RESULTS: Product Intake Fraction

• Leach rate = rate of amount of substance released from pacifier• Kp = rate that substance is absorbed by the skin

• I = Impact on human health • U = Substance uptake through skin • DALYs = Disability Adjusted Life• SF = Severity factor • DR = Dose response of population Years = # yrs. lost due to disability • ED50 = the effect dose to the substance and premature deathrequired for half the • LD50 = the lethal dose required • EV = extrapolation value = 26population to show an effect for half the population to die (Rosenbaum et al. 2011)

RESULTS: Impact Calculations

• Direct impacts are of the same magnitude as or higher than indirect life cycle impacts.• Indirect shampoo impact was not available in the literature. Based on expert judgment, indirect soap impacts were taken as a proxy (indicated in light red).

CONCLUSIONS & FUTURE RESEARCH• Based on the equations developed for dermal uptake and impact, direct dermal exposure is an important pathway to consider when conducting LCA work on consumer products.• LCAs on shampoo and other dermally applied products are needed for direct-indirect impact comparison.• Unlike some LCA models’ existing pathways (inhalation, ingestion) that begin with the substance‘s emission compartment, dermal exposure begins with the product and its use.• This work shows that it will be important for future LCA models to implement dermal exposure as a pathway into their frameworks, possibly with the addition of a dermal products matrix.

⋅÷

=

kgmg

kglifetime

EVkg

mgLD50

lifetimekg

ED50animalanimal

substance

Substances (CAS #)

Di-Isononyl Phthalate

(DINP) (28553-12-0)

Sodium Lauryl Ether

Sulfate (SLES)

(9004-82-4)

Linalool (78-70-6)

Limonene (5989-27-5)

Benzyl Benzoate (120-51-4)

DMDM Hydantoin (6440-58-0)

Use Plasticizer Surfactant (Cleaning

Agent)

Fragrance Fragrance Stabilizer Preservative

Prod

ucts

Pacifier Hand Soap

Shampoo

• Products and substances were selected based on available existing data.

• Kp is a controlling parameter in dermal absorption of substances.• Six Kp models were compared with varying Kow and molecular weight (MW): variation in Kow is a key factor in determining Kp.• Pending further analysis, geometric means of the models' Kp predictions for sample sub-stances were used.

References

Fiserova-Bergerova et al., 1990, Am. J. Ind. Med., 17(5), 617-635.Guy et al., 1992, J. Pharm. Sci., 81(6), 603-604.Humbert et al., accepted 2011, Environ. Sci. Technol., DOI:

10.1021/es103563z.Jolliet et al., 2003, Int. J. LCA, 8(6), 324-330.Koehler et al., 2009, Environ. Sci. Technol., 43(22), 8643-8651.Konemann, ed., 1998, Dutch Natl. Inst. Public Health and Environ.

(RIVM), Report #613320002.

McKone, 1993, Lawrence Livermore Natl. Lab., Report #UCRL-CR-111456.

McKone et al., 1992, Risk Anal., 12(4), 543-557.RIVM, 2010, ConsExpo,

http://www.rivm.nl/en/healthanddisease/ productsafety/ConsExpo.jsp#tcm:13-42840, accessed June 12, 2011.

Rosenbaum et al., 2008, Int. J. LCA, 13(7), 532-546.Rosenbaum et al., accepted 2011, Int. J. LCA, DOI: 10.1007/s11367-011-

0316-4.Wilschut et al., 1995, Chemosphere, 30(7), 1275-1296.

unit functionalDALYs

casesDALYs

kgcases

kgkg

unit functionalkg

SFDRiFSI

unit functionalDALYs

casesDALYs

kgcases

kgkg

unit functionalkg

SFDRPiFUI

intakeemit

intakeemit

indirect PM2.5 pacifier,

intakeproduct in

intakeproduct in

direct hampoo,pacifier/s

=×××=

×××=

=×××=

×××=

1E-13

1E-12

1E-11

1E-10

1E-09

1E-08

1E-07

1E-06

1E-05

1E-04

1E-03

pacifier (DINP)

soap (SLES) shampoo (SLES)

shampoo (DMDM

Hydantoin)

shampoo (linalool)

shampoo (limonene)

shampoo (benzyl

benzoate)

DA

LYs/

functi

onal

uni

t

Impact Comparison

direct

indirect

1E-091E-081E-071E-061E-051E-041E-031E-021E-011E+001E+011E+021E+031E+041E+051E+061E+071E+08

1E-04 1E-01 1E+02 1E+05 1E+08 1E+11

Skin

Per

mea

bili

ty C

oeffi

cien

t (K

p)

Octanol-Water Partition Coefficient (Kow)

Skin Permeability - Octanol-Water Partition CoefficientsMcKone, 1993, model 1, MW=50

McKone, 1993, model 1, MW=500

McKone, 1993, model 2, MW=50

McKone, 1993, model 2, MW=500

McKone et al., 1992, model 3, MW=50

McKone et al., 1992, model 3, MW=500

Fiserova-Bergerova et al., 1992, model 4, MW=50

Fiserova-Bergerova et al., 1992, model 4, MW=500

Guy et al., 1992, model 5, MW=50

Guy et al., 1992, model 5, MW=500

Wilschut et al., 1995, model 6, MW=50

Wilschut et al., 1995, model 6, MW=500

SLES

DMDM Hydantoin

Linalool

Limonene

Benzyl Benzoate

DINP

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hrcmtimethickness product

Kp

napplicatio direct

6rplasticize

22

pacifier

mouthinpacifiermouthing

e1e1PiF

gμg10fg

mincmμgcm

dmind

factor conversionrplasticize fractionweightrate leachareaday per duration exposurelifetime

PiF

exposed