TABLE OF CONTENTS Page No.

6. DERMAL ROUTE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 6.1. EQUATION FOR DERMAL DOSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 6.2. SURFACE AREA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 6.2.1. Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 6.2.2. Measurement Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 6.2.3. Key Body Surface Area Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 6.2.4. Relevant Surface Area Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 6.2.5. Application of Body Surface Area Data . . . . . . . . . . . . . . . . . . . . . . . . . . 4 6.3. SOIL ADHERENCE TO SKIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6.3.1. Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6.3.2. Key Soil Adherence to Skin Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6.3.3. Relevant Soil Adherence to Skin Studies . . . . . . . . . . . . . . . . . . . . . . . . . 6 6.4. RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6.4.1. Body Surface Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6.4.2. Soil Adherence to Skin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6.5. REFERENCES FOR CHAPTER 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 APPENDIX 6A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 ADD ' DA event x EV x ED x EF x SA BW x AT Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 1 ( Eqn. 6 1)

where: ADD = average daily dose ( mg/ kg day); DA = absorbed dose per event ( mg/ cm  event); event 2 EV = event frequency ( events/ day); ED = exposure duration ( years); EF = exposure frequency ( days/ year); SA = skin surface area available for contact ( cm ); 2 BW = body weight ( kg); and AT = averaging time ( days) for noncarcinogenic effects, AT = ED and for carcinogenic effects, AT = 70 years or 25,550 days. 6. DERMAL ROUTE Dermal exposure can occur during a variety of The ADD is used for exposure to chemicals with nonactivities in different environmental media and carcinogenic non chronic effects. For compounds with microenvironments ( U. S. EPA, 1992). These include: carcinogenic or chronic effects, the lifetime average daily ° Water ( e. g., bathing, washing, swimming); over a lifetime. ° Soil ( e. g., outdoor recreation, gardening, For dermal contact with chemicals in soil or water, construction); dermally absorbed average daily dose can be estimated by ° Sediment ( e. g., wading, fishing); ( U. S. EPA, 1992b): ° Liquids ( e. g., use of commercial products); ° Vapors/ fumes ( e. g., use of commercial products); and ° Indoors ( e. g., carpets, floors, countertops).

The major factors that must be considered when estimating dermal exposure are: the chemical concentration in contact with the skin, the potential dose, the extent of skin surface area exposed, the duration of exposure, the absorption of the chemical through the skin, the internal dose, and the amount of chemical that can be delivered to a target organ ( i. e., biologically effective dose) ( see Figure 6 1). A detailed discussion of these factors can be found in Guidelines for Exposure Assessment ( U. S. EPA, 1992a). This chapter focuses on measurements of body surface areas and various factors needed to estimate dermal exposure to chemicals in water and soil. Information This method is to be used to calculate the absorbed dose of concerning dermal exposure to pollutants in indoor a chemical. Total body surface area ( SA) is assumed to be environments is limited. Useful information concerning exposed for a period of time ( ED). estimates of body surface area can be found in For dermal contact with water, the DA is " Development of Statistical Distributions or Ranges of estimated with consideration for the permeability coefficient Standard Factors Used in Exposure Assessments" ( U. S. from water, the chemical concentration in water, and the EPA, 1985). " Dermal Exposure Assessment: Principles event duration. The approach to estimate DA is different and Applications ( U. S. EPA, 1992b), provides detailed for inorganic and organic compounds. The nonsteady state information concerning dermal exposure using a stepwise approach to estimate the dermally absorbed dose from water guide in the exposure assessment process. is recommended as the preferred approach for organics The available studies have been classified as either which exhibit octanol water partitioning ( U. S. EPA, key or relevant based on their applicability to exposure 1992b). First, this approach more accurately reflects assessment needs and are summarized in this chapter. normal human exposure conditions since the short contact Recommended values are based on the results of the key times associated with bathing and swimming generally studies. Relevant studies are presented to provide an added mean that steady state will not occur. Second, the approach perspective on the state of knowledge pertaining to dermal accounts for uptake that can occur after the actual exposure exposure factors. All tables and figures presenting data event due to absorption of residual chemical trapped in skin from these studies are shown at the end of this chapter. tissue. Use of the nonsteady state model for organics has 6.1. EQUATION FOR DERMAL DOSE The average daily dose ( ADD) is the dose rate traditional steady state approach be applied to inorganics averaged over a pathway specific period of exposure ( U. S. EPA, 1992b). Detailed information concerning how expressed as a daily dose on a per unit body weight basis.

dose ( LADD) is used. The LADD is the dose rate averaged event event implications for selecting permeability coefficient ( K ) p values ( U. S. EPA, 1992b). It is recommended that the to estimate absorbed dose per event ( DA ) and K event p Volume I  General Factors Chapter 6  Dermal Page Exposure Factors Handbook 6 2 August 1997 values can be found in Section 5.3.1 of " Dermal Exposure Assessment: Principles and Applications" ( U. S. EPA, Coating, triangulation, and surface integration are 1992b). direct measurement techniques that have been used to For dermal contact with contaminated soil, measure total body surface area and the surface area of estimation of the DA is different from the estimation for specific body parts. Consideration has been given for event dermal contact with chemicals in water. It is based on the differences due to age, gender, and race. The results of the concentration of the chemical in soil, the adherence factor various techniques have been summarized in " Development of soil to skin, and the absorption fraction. Information for of Statistical Distributions or Ranges of Standard Factors DA estimation from soil contact can be found in U. S. Used in Exposure Assessments" ( U. S. EPA, 1985). The event EPA ( 1992b), Section 6.4. coating method consists of coating either the whole body or The apparent simplicity of the absorption fraction specific body regions with a substance of known or ( percent absorbed) makes this approach appealing. measured area. Triangulation consists of marking the area However, it is not practical to apply it to water contact of the body into geometric figures, then calculating the scenarios, such as swimming, because of the difficulty in figure areas from their linear dimensions. Surface estimating the total material contacted ( U. S. EPA, 1992b). integration is performed by using a planimeter and adding It is assumed that there is essentially an infinite amount of the areas. material available, and that the chemical will be replaced The triangulation measurement technique developed continuously, thereby increasing the amount of material by Boyd ( 1935) has been found to be highly reliable. It ( containing the chemical) available by some large unknown estimates the surface area of the body using geometric amount. Therefore, the permeability coefficient approximations that assume parts of the body resemble  based approach is recommended over the absorption geometric solids ( Boyd, 1935). More recently, Popendorf fraction approach for determining the dermally absorbed and Leffingwell ( 1976), and Haycock et al. ( 1978) have dose of chemicals in aqueous media. developed similar geometric methods that assume body Before the absorption fraction approach can be used parts correspond to geometric solids, such as the sphere and in soil contact scenarios, the contaminant concentration in cylinder. A linear method proposed by DuBois and DuBois soil must be established. Not all of the chemical in a layer ( 1916) is based on the principle that the surface areas of the of dirt applied to skin may be bioavailable, nor is it assumed parts of the body are proportional, rather than equal to the to be an internal dose. Because of the lack of K data for surface area of the solids they resemble. p compounds bound to soil, and reduced uncertainty in In addition to direct measurement techniques, several defining an applied dose, the absorption fraction based formulae have been proposed to estimate body surface area approach is suggested for determining the internal dose of from measurements of other major body dimensions ( i. e., chemicals in soil. More detailed explanation of the height and weight) ( U. S. EPA, 1985). Generally, the equations, assumptions, and approaches can be found in formulae are based on the principles that body density and " Dermal Exposure Assessment: Principles and shape are roughly the same and that the relationship of Applications" ( U. S. EPA. 1992b). surface area to any dimension may be represented by the 6.2. SURFACE AREA 6.2.1. Background The total surface area of skin exposed to a are presented in Appendix 6A. contaminant must be determined using measurement or estimation techniques before conducting a dermal exposure assessment. Depending on the exposure scenario, estimation of the surface area for the total body or a specific body part can be used to calculate the contact rate for the pollutant. This section presents estimates for total body surface area and for body parts and presents information on the application of body surface area data. 6.2.2. Measurement Techniques curve of central tendency of their plotted values or by the algebraic expression for the curve. A discussion and comparison of formulae to determine total body surface area 6.2.3. Key Body Surface Area Studies U. S. EPA ( 1985)  Development of Statistical Distributions or Ranges of Standard Factors Used in Exposure Assessments  U. S. EPA ( 1985) analyzed the direct surface area measurement data of Gehan and George ( 1970) using the Statistical Processing System ( SPS) software package of Buhyoff et al. ( 1982). Gehan and George ( 1970) selected 401 measurements made by Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 3 Boyd ( 1935) that were complete for surface area, height, present the percentage of total body surface by body part for weight, and age for their analysis. Boyd ( 1935) had men and women. reported surface area estimates for 1,114 individuals using Percentile estimates for total surface area of male and coating, triangulation, or surface integration methods ( U. S. female children presented in Tables 6 6 and 6 7 were EPA, 1985). calculated using the total surface area regression equation, U. S. EPA ( 1985) used SPS to generate equations to NHANES II height and weight data, and using QNTLS. calculate surface area as a function of height and weight. Estimates are not included for children younger than 2 years These equations were then used to calculate body surface old because NHANES height data are not available for this area distributions of the U. S. population using the height age group. For children, the error associated with height and weight data obtained from the National Health and and weight cannot be assumed to be zero because of their Nutrition Examination Survey ( NHANES) II and the relatively small sizes. Therefore, the standard errors of the computer program QNTLS of Rochon and Kalsbeek percentile estimates cannot be estimated, since it cannot be ( 1983). assumed that the errors associated with the exogenous The equation proposed by Gehan and George ( 1970) variables ( height and weight) are independent of that was determined by U. S. EPA ( 1985) to be the best choice associated with the model; there are insufficient data to for estimating total body surface area. However, the paper determine the relationship between these errors. by Gehan and George ( 1970) gave insufficient information Measurements of the surface area of children's body to estimate the standard error about the regression. parts are summarized as a percentage of total surface area Therefore, U. S. EPA ( 1985) used the 401 direct in Table 6 8. Because of the small sample size, the data measurements of children and adults and reanalyzed the cannot be assumed to represent the average percentage of data using the formula of Dubois and Dubois ( 1916) and surface area by body part for all children. Note that the SPS to obtain the standard error ( U. S. EPA, 1985). percent of total body surface area contributed by the head Regression equations were developed for specific decreases from childhood to adult, while the percent body parts using the Dubois and Dubois ( 1916) formula contributed by the leg increases. and using the surface area of various body parts provided by Boyd ( 1935) and Van Graan ( 1969) in conjunction with SPS. Regression equations for adults were developed for the head, trunk ( including the neck), upper extremities ( arms and hands, upper arms, and forearms) and lower extremities ( legs and feet, thighs, and lower legs) ( U. S. EPA, 1985). Table 6 1 presents a summary of the equation parameters developed by U. S. EPA ( 1985) for calculating surface area of adult body parts. Equations to estimate the body part surface area of children were not developed because of insufficient data. Percentile estimates of total surface area and surface area of body parts developed by U. S. EPA ( 1985) using the regression equations and NHANES II height and weight data are presented in Tables 6 2 and 6 3 for adult males and adult females, respectively. The calculated mean surface areas of body parts for men and women are presented in Table 6 4. The standard deviation, the minimum value, and the maximum value for each body part are included. The median total body surface area for men and women and the corresponding standard errors about the regressions are also given. It has been assumed that errors associated with height and weight are negligible ( U. S. EPA, 1985). The data in Table 6 5 Phillips et al. ( 1993)  Distributions of Total Skin Surface Area to Body Weight Ratios  Phillips et al. ( 1993) observed a strong correlation ( 0.986) between body surface area and body weight and studied the effect of using these factors as independent variables in the LADD equation. Phillips et al. ( 1993) concluded that, because of the correlation between these two variables, the use of body surface area to body weight ( SA/ BW) ratios in human exposure assessments is more appropriate than treating these factors as independent variables. Direct measurement ( coating, triangulation, and surface integration) data from the scientific literature were used to calculate body surface area to body weight ( SA/ BW) ratios for three age groups ( infants aged 0 to 2 years, children aged 2.1 to 17.9 years, and adults 18 years and older). These ratios were calculated by dividing body surface areas by corresponding body weights for the 401 individuals analyzed by Gehan and George ( 1970) and summarized by U. S. EPA ( 1985). Distributions of SA/ BW ratios were developed and summary statistics were calculated for each of the three age groups and the combined data set. Summary statistics for these populations are presented in Table 6 9. The shapes of these SA/ BW distributions were determined using Volume I  General Factors Chapter 6  Dermal Page Exposure Factors Handbook 6 4 August 1997 SA= 4W+ 7/ W+ 90 ( Eqn. 6 2)

where: SA = Surface Area ( m ); and 2 W = Weight ( kg). D'Agostino's test. The results indicate that the SA/ BW weight and the formulae described above. A total of 5,000 ratios for infants are lognormally distributed and the random samples each for men and women were selected SA/ BW ratios for adults and all ages combined are normally from the two correlated bivariate distributions. Body distributed ( Figure 6 2). SA/ BW ratios for children were surface area calculations were made for each sample, and neither normally nor lognormally distributed. According to for each formula, resulting in body surface area Phillips et al. ( 1993), SA/ BW ratios should be used to distributions. Murray and Burmaster ( 1992), found that the calculate LADDs by replacing the body surface area factor body surface area frequency distributions were similar for in the numerator of the LADD equation with the SA/ BW the four models ( Table 6 10). Using the U. S. EPA ( 1985) ratio and eliminating the body weight factor in the formula, the median surface area values were calculated to denominator of the LADD equation. be 1.96 m for men and 1.69 m for women. The median The effect of gender and age on SA/ BW distribution value for women is identical to that generated by U. S. EPA was also analyzed by classifying the 401 observations by ( 1985) but differs for men by approximately 1 percent. gender and age. Statistical analyses indicated no significant Body surface area was found to have lognormal differences between SA/ BW ratios for males and females. distributions for both men and women ( Figure 6 3). It was SA/ BW ratios were found to decrease with increasing age. also found that assuming correlation between height and 6.2.4. Relevant Surface Area Studies Murray and Burmaster ( 1992)  Estimated AIHC ( 1994)  Exposure Factors Sourcebook  The Distributions for Total Body Surface Area of Men and Women in the United States  In this study, distributions of total body surface area for men and women ages 18 to 74 years were estimated using Monte Carlo simulations based on height and weight distribution data. Four different formulae for estimating body surface area as a function of height and weight were employed: Dubois and Dubois ( 1916); Boyd ( 1935); U. S. EPA ( 1985); and Costeff ( 1966). The formulae of Dubois and Dubois ( 1916); Boyd ( 1935); and U. S. EPA ( 1985) are based on height and weight. They are discussed in Appendix 6A. The formula developed by Costeff ( 1966) is based on 220 observations that estimate body surface area based on weight only. This formula is:

Formulae were compared and the effect of the correlation between height and weight on the body surface area distribution was analyzed. Monte Carlo simulations were conducted to estimate body surface area distributions. They were based on the bivariate distributions estimated by Brainard and Burmaster ( 1992) for height and natural logarithm of 2 2 weight influences the final distribution by less than 1 percent.

Exposure Factors Sourcebook ( AIHC, 1994) provides similar body surface area data as presented here. Consistent with this document, average and percentile values are presented on the basis of age and gender. In addition, the Sourcebook presents point estimates of exposed skin surface areas for various scenarios on the basis of several published studies. Finally, the Sourcebook presents probability distributions based on U. S. EPA ( 1989) and as derived by Thompson and Burmaster ( 1991); Versar ( 1991); and Brorby and Finley ( 1993). For each distribution, the @ Risk formula is provided for direct use in the @ Risk simulation software ( Palisade, 1992). The organization of this document, makes it very convenient to use in support of Monte Carlo analysis. The reviews of the supporting studies are very brief with little analysis of their strengths and weaknesses. The Sourcebook has been classified as a relevant rather than key study because it is not the primary source for the data used to make recommendations in this document. The Sourcebook is very similar to this document in the sense that it summarizes exposure factor data and recommends values. As such, it is clearly relevant as an alternative information source on body surface area as well as other exposure factors.

6.2.5. Application of Body Surface Area Data In many settings, it is likely that only certain parts of the body are exposed. All body parts that come in contact with a chemical must be considered to estimate the total surface area of the body exposed. The data in Table 6 4 may be used to estimate the total surface area of Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 5 the particular body part( s). For example, to assess exposure For default purposes, adult body surface areas of to a chemical in a cleaning product for which only the hands 20,000 cm ( central estimate) to 23,000 cm ( upper are exposed, surface area values for hands from Table 6 4 percentile) are recommended in U. S. EPA ( 1992b). Tables can be used. For exposure to both hands and arms, mean 6 2 and 6 3 can also be used when the default values are not surface areas for these parts from Table 6 4 may be preferred. Central and upper percentile values for children summed to estimate the total surface area exposed. The should be derived from Table 6 6 or 6 7. mean surface area of these body parts for men and women Unlike exposure to liquids, clothing may or may not is as follows: be effective in limiting the extent of exposure to soil. The Surface Area ( m ) 2 Men Women Arms ( includes upper arms and forearms) 0.228 0.210 Hands 0.084 0.075 Total area 0.312 0.285 Therefore, the total body part surface area that may be in contact with the chemical in the cleaning product in this example is 0.312 m for men and 0.285 m for women. 2 2 A common assumption is that clothing prevents dermal contact and subsequent absorption of contaminants. This assumption may be false in cases where the chemical may be able to penetrate clothing, such as in a fine dust or liquid suspension. Studies using personal patch monitors placed beneath clothing of pesticide workers exposed to fine mists and vapors show that a significant proportion of dermal exposure may occur at anatomical sites covered by clothing ( U. S. EPA, 1992b). In addition, it has been demonstrated that a " pumping" effect can occur which causes material to move under loose clothing ( U. S. EPA, 1992b). Furthermore, studies have demonstrated that hands cannot be considered to be protected from exposure even if waterproof gloves are worn ( U. S. EPA, 1992b). This may be due to contamination to the interior surface of the gloves when donning or removing them during work activities ( U. S. EPA, 1992b). Depending on the task, pesticide workers have been shown to experience 12 percent to 43 percent of their total exposure through their hands, approximately 20 percent to 23 percent through their heads and necks, and 36 percent to 64 percent through their torsos and arms, despite the use of protective gloves and clothing ( U. S. EPA, 1992b). For swimming and bathing scenarios, past exposure assessments have assumed that 75 percent to 100 percent of the skin surface is exposed ( U. S. EPA, 1992b). As shown in Table 6 4, total adult body surface areas can vary from about 17,000 cm to 23,000 cm . The mean is reported as 2 2 approximately 20,000 cm . 2 2 2 1989 Exposure Factors Handbook presented two adult clothing scenarios for outdoor activities ( U. S. EPA, 1989):

Central tendency mid range: Individual wears long sleeve shirt, pants, and shoes. The exposed skin surface is limited to the head and hands ( 2,000 cm ). 2 Upper percentile: Individual wears a short sleeve shirt, shorts, and shoes. The exposed skin surface is limited to the head, hands, forearms, and lower legs ( 5,300 cm ). 2 The clothing scenarios presented above, suggest that roughly 10 percent to 25 percent of the skin area may be exposed to soil. Since some studies have suggested that exposure can occur under clothing, the upper end of this range was selected in Dermal Exposure Assessment: Principles and Applications ( U. S. EPA, 1992b) for deriving defaults. Thus, taking 25 percent of the total body surface area results in defaults for adults of 5,000 cm to 2 5,800 cm . These values were obtained from the body 2 surface areas in Table 6 2 after rounding to 20,000 cm and 2 23,000 cm , respectively. The range of defaults for children 2 can be derived by multiplying the 50th and 95th percentiles by 0.25 for the ages of interest. When addressing soil contact exposures, assessors may want to refine estimates of surface area exposed on the basis of seasonal conditions. For example, in moderate climates, it may be reasonable to assume that 5 percent of the skin is exposed during the winter, 10 percent during the spring and fall, and 25 percent during the summer. The previous discussion, has presented information about the area of skin exposed to soil. These estimates of exposed skin area should be useful to assessors using the traditional approach of multiplying the soil adherence factor by exposed skin area to estimate the total amount of soil on skin. The next section presents soil adherence data specific to activity and body part and is designed to be Volume I  General Factors Chapter 6  Dermal Page Exposure Factors Handbook 6 6 August 1997 combined with the total surface area of that body part. No outdoor activities: greenhouse gardening, tae kwon do reduction of body part area is made for clothing coverage karate, soccer, rugby, reed gathering, irrigation installation, using this approach. Thus, assessors who adopt this truck farming, and playing in mud. A summary of field approach, should not use the defaults presented above for studies by activity, gender, age, field conditions, and soil exposed skin area. Rather, they should use Table 6 4 clothing worn is presented in Table 6 11. Subjects' body to obtain total surface areas of specific body parts. See surfaces ( forearms, hands, lower legs in all cases, faces, detailed discussion below. and/ or feet; pairs in some cases) were washed before and 6.3. SOIL ADHERENCE TO SKIN 6.3.1. Background Soil adherence to the surface of the skin is a required presented in Table 6 12. Results presented are based on parameter to calculate dermal dose when the exposure direct measurement of soil loading on the surfaces of skin scenario involves dermal contact with a chemical in soil. A before and after occupational and recreational activities that number of studies have attempted to determine the may be expected to have soil contact ( Kissel et al., 1996b). magnitude of dermal soil adherence. These studies are described in detail in U. S. EPA ( 1992b). This section summarizes recent studies that estimate soil adherence to skin for use as exposure factors.

6.3.2. Key Soil Adherence to Skin Studies Kissel et al. ( 1996a)  Factors Affecting Soil Adherence to Skin in Hand Press Trials: Investigation of Samples of dirt from the hands of subjects were collected Soil Contact and Skin Coverage  Kissel et al. ( 1996a) conducted soil adherence experiments using five soil types ( descriptor) obtained locally in the Seattle, Washington, area: sand ( 211), loamy sand ( CP), loamy sand ( 85), sandy loam ( 228), and silt loam ( 72). All soils were analyzed by hydrometer ( settling velocity) to determine composition. Clay contents ranged from 0.5 to 7.0 percent. Organic carbon content, determined by combustion, ranged from 0.7 to 4.6 percent. Soils were dry sieved to obtain particle size ranges of < 150, 150 250, and > 250 F m. For each soil type, the amount of soil adhering to an adult female hand, using both sieved and unsieved soils, was determined by measuring the difference in soil sample weight before and after the hand was pressed into a pan containing the test soil. Loadings were estimated by dividing the recovered soil mass by total hand area, although loading occurred Roels et al. ( 1980)  Exposure to Lead by the Oral primarily on only one side of the hand. Results showed that generally, soil adherence to hands could be directly correlated with moisture content, inversely correlated with particle size, and independent of clay content or organic carbon content. Kissel et al. ( 1996b)  Field Measurement of Dermal Soil Loading Attributable to Various Activities: mL dilute nitric acid. The amount of lead on the hands was Implications for Exposure Assessment  Further experiments were conducted by Kissel et al. ( 1996b) to estimate soil adherence associated with various indoor and after monitored activities. Paired samples were pooled into single ones. Mass recovered was converted to loading using allometric models of surface area. These data are 6.3.3. Relevant Soil Adherence to Skin Studies Lepow et al. ( 1975)  Investigations into Sources of Lead in the Environment of Urban Children  This study was conducted to identify the behavioral and environmental factors contributing to elevated lead levels in ten preschool children. The study was performed over 6 to 25 months.

during the course of play around the areas where they lived. Preweighed self adhesive labels were used to sample a standard area on the palm of the hands of 16 male and female children. The labels were pressed on a single area, often pressed several times, to obtain an adequate sample. In the laboratory, labels were equilibrated in a desiccant cabinet for 24 hours ( comparable to the preweighed desiccation), then the total weight was recorded. The mean weight of dirt from the 22 hand sample labels was 11 mg. This corresponds to 0.51 mg/ cm . Lepow et al. ( 1975) 2 reported that this amount ( 11 mg) represented only a small fraction ( percent not specified) of the total amount of surface dirt present on the hands, because much of the dirt may be trapped in skin folds and creases or there may be a patchy distribution of dirt on hands.

and the Pulmonary Routes of Children Living in the Vicinity of a Primary Lead Smelter  Roels et al. ( 1980) examined blood lead levels among 661 children, 9 to 14 years old, who lived in the vicinity of a large lead smelter in Brussels, Belgium. During five different study periods, lead levels were assessed by rinsing the childrens' hands in 500 divided by the concentration of lead in soil to Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 7 estimate the amount of soil adhering to the hands. The µ m, and 0.58 mg/ cm for unsieved soils. Analysis of mean soil amount adhering to the hands was 0.159 grams. variance statistics showed that the most important factor Que Hee et al. ( 1985)  Evolution of Efficient Methods to Sample Lead Sources, Such as House Dust and Hand Dust, in the Homes of Children  Que Hee et al. ( 1985) used soil having particle sizes ranging from # 44 to 833 µ m diameters, fractionated into six size ranges, to estimate the amount that adhered to the palm of the hand that are assumed to be approximately 160 cm ( test subject 2 with an average total body surface area of 16,000 cm and 2 a total hand surface area of 400 cm ). The amount of soil 2 that adhered to skin was determined by applying approximately 5 g of soil for each size fraction, removing excess soil by shaking the hands, and then measuring the difference in weight before and after application. Several Exposure of Humans to Soil in a Residential Setting  assumptions were made to apply these results to other soil Sedman ( 1989) used the estimate from Roels et al. ( 1980), types and exposure scenarios: ( a) the soil is composed of 0.159 g, and the average surface area of the hand of an 11 particles of the indicated diameters; ( b) all soil types and year old, 307 cm to estimate the amount of soil adhering particle sizes adhere to the skin to the degree observed in per unit area of skin to be 0.9 mg/ cm . This assumed that this study; and an equivalent weight of particles of any approximately 60 percent ( 185 cm ) of the lead on the diameter adhere to the same surface area of skin. On hands was recovered by the method employed by Roels et average, 31.2 mg of soil adhered to the palm of the hand. al. ( 1980). Driver et al. ( 1989)  Soil Adherence to Human Skin  Driver et al. ( 1989) conducted soil adherence experiments using various soil types collected from sites in Virginia. A total of five soil types were collected: Hyde, Chapanoke, Panorama, Jackland, and Montalto. Both top soils and subsoils were collected for each soil type. The soils were also characterized by cation exchange capacity, organic content, clay mineralogy, and particle size distribution. The soils were dry sieved to obtain particle sizes of # 250 µ m and # 150 µ m. For each soil type, the amount of soil Percutaneous Absorption of Benzo[ a] pyrene from adhering to adult male hands, using both sieved and unsieved soils, was determined gravimetrically ( i. e., measuring the difference in soil sample weight before and after soil application to the hands). An attempt was made to measure only the minimal or " monolayer" of soil adhering to the hands. This was done by mixing a pre weighed amount of soil over the entire surface area of the hands for a period of approximately 30 seconds, followed by removal of excess soil by gently rubbing the hands together after contact with the soil. Excess soil that was removed from the hands was collected, weighed, and compared to the original soil sample weight. The authors measured average adherence of 1.40 mg/ cm2 for particle sizes less than 150 µ m, 0.95 mg/ cm for particle 2 sizes less than 250 2 affecting adherence variability was particle size ( p < 0.001). The next most important factor is soil type and subtype ( p < 0.001). The interaction of soil type and particle size was also significant, but at a lower significance level ( p < 0.01). Driver et al. ( 1989) found statistically significant increases in soil adherence with decreasing particle size; whereas, Que Hee et al. ( 1985) found relatively small changes with changes in particle size. The amount of soil adherence found by Driver et al. ( 1989) was greater than that reported by Que Hee et al. ( 1985). Sedman ( 1989)  The Development of Applied Action Levels for Soil Contact: A Scenario for the 2 2 2 Sedman ( 1989) used estimates from Lepow et al. ( 1975), Roels et al. ( 1980), and Que Hee et al. ( 1985) to develop a maximum soil load that could occur on the skin. A rounded arithmetic mean of 0.5 mg/ cm was calculated 2 from these three studies. According to Sedman ( 1989), this was near the maximum load of soil that could occur on the skin but it is unlikely that most skin surfaces would be covered with this amount of soil ( Sedman, 1989). Yang et al. ( 1989)  In vitro and In vivo Petroleum Crude  Fortified Soil in the Rat  Yang et al. ( 1989) evaluated the percutaneous absorption of benzo[ a] pyrene ( BAP) in petroleum crude oil sorbed on soil using a modified in vitro technique. This method was used in preliminary experiments to determine the minimum amount of soil adhering to the skin of rats. Based on these results, percutaneous absorption experiments with the crude sorbed soil were conducted with soil particles of < 150 F m only. This particle size was intended to represent the composition of the soil adhering to the skin surface. Approximately 9 mg/ cm of soil was found to be the 2 minimum amount required for a " monolayer" coverage of the skin surface in both in vitro and in vivo experiments. This value is larger than reports for human skin in the studies of Kissel et al., 1996a, b; Lepow et al., 1975; Roels et al., 1980; and Que Hee et al., Volume I  General Factors Chapter 6  Dermal Page Exposure Factors Handbook 6 8 August 1997 1985. Differences between the rat and human soil adhesion because these data are straightforward determinations for findings may be the result of differences in rat and human most scenarios. However, for others, additional skin texture, the types of soils used, soil moisture content or considerations may need to be addressed. For example, ( 1) possibly the methods of measuring soil adhesion ( Yang et the type of clothing worn could have a significant effect on al., 1989). the surface area exposed, and ( 2) climatic conditions will 6.4. RECOMMENDATIONS 6.4.1. Body Surface Area Body surface area estimates are based on direct activities and soil contact are presented in Activity Patterns, measurements. Re analysis of data collected by Boyd Volume III, Chapter 15 of this report. For each parameter, ( 1935) by several investigators ( Gehan and George, 1970; recommended values were derived for average and upper U. S. EPA, 1985; Murray and Burmaster, 1992; Phillips et percentile values. Each of these considerations are also al., 1993) constitutes much of this literature. Methods are discussed in more detail in U. S. EPA ( 1992b). Data in highly reproducible and the results are widely accepted. Tables 6 2 and 6 3 can be used when surface area The representativeness of these data to the general distributions are preferred. A range of recommended values population is somewhat limited since variability due to race for estimates of the skin surface area of children may be or gender have not been systematically addressed. taken from Tables 6 6 and 6 7 using the 50th and 95th Individual body surface area studies are summarized percentile values for age( s) of concern. The recommended in Table 6 13 and the recommendations for body surface 50th and 95th percentile values for adult skin surface area area are summarized in Table 6 14. Table 6 15 presents provided in U. S. EPA ( 1992b) are presented in Table 6 16. the confidence ratings for various aspects of the recommendations for body surface area. The U. S. EPA ( 1985) study is based on generally accepted measurements Table 6 17 summarizes the relevant and key studies that enjoy widespread usage, summarizes and compares addressing soil adherence to skin. Both Lepow et al. ( 1975) previous reports in the literature, provides statistical and Roels et al. ( 1980) monitored typical exposures in distributions for adults, and provides data for total body children. They attempted to estimate typical exposure by surface area and body parts by gender for adults and recovery of accumulated soil from hands at specific time children. However, the results are based on 401 selected intervals. The efficiency of their sample collection methods measurements from the original 1,114 made by Boyd is not known and may be subject to error. Only children ( 1935). More than half of the measurements are from were studied which may limit generalizing these results to children. Therefore, these estimates may be subject to adults. Later studies ( Que Hee et al., 1985 and Driver et al., selection bias and may not be representative of the general 1989) attempted to characterize both soil properties and population nor specific ethnic groups. Phillips et al. ( 1993) sample collection efficiency to estimate adherence of soil to analyses are based on direct measurement data that provide skin. However, the experimental conditions used to expose distributions of body surface area to calculate LADD. The skin to soil may not reflect typical dermal exposure results are consistent with previous efforts to estimate body situations. This provides useful information about the surface area. Analyses are based on 401 measurements influence of soil characteristics on skin adherence, but the selected from the original 1,114 measurements made by intimate contact of skin with soil required under the Boyd ( 1935) and data were not analyzed for specific body controlled experimental conditions in the studies by Driver parts. The study by Murray and Burmaster ( 1992) provides et al. ( 1989) and Que Hee et al. ( 1985) may have frequency distributions for body surface area for men and exaggerated the amount of adherence over what typically women and produces results that are similar to those occurs. obtained by the U. S. EPA ( 1985), but do not provide data More recently, Kissel et al. ( 1996a; 1996b) have for body parts nor can results be applied to children. related dermal adherence to soil characteristics and to For most dermal exposure scenarios concerning specific activities. In all cases, experimental design and adults, it is recommended that the body surface areas measurement methods are straightforward and reproducible, presented in Table 6 4 be used after determining which but application of results is limited. Both controlled body parts will be exposed. Table 6 4 was selected experiments and field studies are based on a also affect the type of clothing worn and, thus, the skin surface area exposed. Frequency, event, and exposure duration for water 6.4.2. Soil Adherence to Skin Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 9 limited number of measurements. Specific situations have EPA is sponsoring research to develop such an approach. been selected to assess soil adherence to skin. As this information becomes availble, updated Consequently, variation due to individuals, protective recommendations will be issued. clothing, temporal, or seasonal factors remain to be studied Table 6 12 provides the best estimates available on in more detail. Therefore, caution is required in activity specific adherence values, but are based on limited interpretation and application of these results for exposure data. Therefore, they have a high degree of uncertainty such assessments. that considerable judgment must be used when selecting These studies are based on limited data, but suggest: them for an assessment. The confidence ratings for various ° Soil properties influence adherence. Adherence 18. Insufficient data are available to develop a distribution increases with moisture content, decreases with or a probability function for soil loadings. particle size, but is relatively unaffected by clay or Past EPA guidance has recommended assuming that organic carbon content. soil exposure occurs primarily to exposed body surfaces and ° Adherence levels vary considerably across exposed skin area. The approach recommended above for different parts of the body. The highest levels were estimating soil adherence addresses this issue in a different found on common contact points such as hands, manner. This change was motivated by two developments. knees, and elbows; the least was detected on the First, increased acceptance that soil and dust particles can face. get under clothing and be deposited on skin. Second, recent ° Adherence levels vary with activity. In general, parts ( whether or not they were covered by clothing) and the highest levels of soil adherence were seen in averaged the amount of soil adhering to skin over the area outdoor workers such as farmers and irrigation of entire body part. The soil adherence levels resulting from system installers, followed by outdoor recreation, these new studies must be combined with the surface area and gardening activities. Very high adherence of the entire body part ( not merely unclothed surface area) levels were seen in individuals contacting wet to estimate the amount of contaminant on skin. An soils such as might occur during wading or other important caveat, however, is that this approach assumes shore area recreational activities. that clothing in the exposure scenario of interest matches In consideration, of these general observations and levels such that the same degree of protection provided by the recent data from Kissel et al. ( 1996a, 1996b), changes clothing can be assumed in both cases. If clothing differs are needed from past EPA recommendations which used significantly between the studies reported here and the one adherence value to represent all soils, body parts, and exposure scenarios under investigation, considerable activities. One approach would be to select the activity judgment is needed to adjust either the adherence level or from Table 6 11 which best represents the exposure surface area assumption. scenario of concern and use the corresponding adherence The dermal adherence value represents the amount value from Table 6 12. Although this approach represents of soil on the skin at the time of measurement. Assuming an improvement, it still has shortcomings. For example, it that the amount measured on the skin represents its is difficult to decide which activity in Table 6 12 is most accumulation between washings and that people wash at representative of a typical residential setting involving a least once per day, these adherence values can be variety of activities. It may be useful to combine these interpreted as daily contact rates ( U. S. EPA, 1992b). activities into general classes of low, moderate, and high However, this is not recommended because the residence contact. In the future, it may be possible to combine time of soils on skin has not been studied. Instead, it is activity specific soil adherence estimates with survey recommended that these adherence values be interpreted on specific soil adherence estimates with survey derived data an event basis ( U. S. EPA, 1992b). on activity frequency and duration to develop overall average soil contact rates. aspects of this recommendation are summarized in Table 6

used typical clothing scenarios to derive estimates of studies of soil adherence have measured soil on entire body the clothing in the studies used to derive these adherence Volume I  General Factors Chapter 6  Dermal Page Exposure Factors Handbook 6 10 August 1997 6.5. REFERENCES FOR CHAPTER 6 American Industrial Health Council ( AIHC). ( 1994) Kissel, J.; Richter, K.; Fenske, R. ( 1996b) Field Exposure factors sourcebook. Washington, DC: measurements of dermal soil loading attributable to AIHC. various activities: Implications for exposure Boyd, E. ( 1935) The growth of the surface area of the assessment. Risk Anal. 16( 1): 116 125. human body. Minneapolis, Minnesota: University Lepow, M. L.; Bruckman, L.; Gillette, M.; Markowitz, S.; of Minnesota Press. Rubino, R.; Kapish, J. ( 1975) Investigations into Brainard, J. B.; Burmaster, D. E. ( 1992) Bivariate sources of lead in the environment of urban children. distributions for height and weight, men and Environ. Res. 10: 415 426. women in the United States. Risk Anal. Murray, D. M.; Burmaster, D. E. ( 1992) Estimated 12( 2): 267 275. distributions for total surface area of men and women Brorby, G.; Finley B. ( 1993) Standard probability in the United States. J. Expos. Anal. Environ. density functions for routine use in environmental Epidemiol. 3( 4): 451 462. health risk assessment. Presented at the Society of Palisade. ( 1992) @ Risk users guide. Palisade Risk Analysis Annual Meeting, December 1993, Corporation, Newfield, NY. Savannah, GA. Phillips, L. J.; Fares, R. J.; Schweer, L. G. ( 1993) Buhyoff, G. J.; Rauscher, H. M.; Hull, R. B.; Killeen, K.; Distributions of total skin surface area to body Kirk, R. C. ( 1982) User's Manual for Statistical weight ratios for use in dermal exposure Processing System ( version 3C. 1). Southeast assessments. J. Expos. Anal. Environ. Epidemiol. Technical Associates, Inc. 3( 3): 331 338. Costeff, H. ( 1966) A simple empirical formula for Popendorf, W. J.; Leffingwell, J. T. ( 1976) Regulating calculating approximate surface area in children. OP pesticide residues for farmworker protection. In: Arch. Dis. Childh. 41: 681 683. Residue Review 82. New York, NY: Springer Driver, J. H.; Konz, J. J.; Whitmyre, G. K. ( 1989) Soil Verlag New York, Inc., 1982. pp. 125 201. adherence to human skin. Bull. Environ. Contam. Que Hee, S. S.; Peace, B.; Clark, C. S.; Boyle, J. R.; Toxicol. 43: 814 820. Bornschein, R. L.; Hammond, P. B. ( 1985) Dubois, D.; Dubois, E. F. ( 1916) A formula to estimate Evolution of efficient methods to sample lead the approximate surface area if height and weight sources, such as house dust and hand dust, in the be known. Arch. of Intern. Med. 17: 863 871. homes of children. Environ. Res. 38: 77 95. Gehan, E.; George, G. L. ( 1970) Estimation of human Rochon, J.; Kalsbeek, W. D. ( 1983) Variance estimation body surface area from height and weight. Cancer from multi stage sample survey data: the jackknife Chemother. Rep. 54( 4): 225 235. repeated replicate approach. Presented at 1983 SAS Geigy Scientific Tables ( 1981) Nomograms for Users Group Conference, New Orleans, Louisiania, determination of body surface area from height and January 1983. mass. Lentner, C. ( ed.). CIBA Geigy Roels, H. A.; Buchet, J. P.; Lauwenys, R. R.; Branx, P.; Corporation, West Caldwell, NJ. pp. 226 227. Claeys Thoreau, F.; Lafontaine, A.; Verduyn, G. George, S. L.; Gehan, E. A.; Haycock, G. B.; Schwartz, ( 1980) Exposure to lead by oral and pulmonary G. J. ( 1979) Letters to the editor. J. Ped. routes of children living in the vicinity of a primary 94( 2): 342. lead smelter. Environ. Res. 22: 81 94. Haycock, G. B.; Schwartz, G. J.; Wisotsky, D. H. ( 1978) Sedman, R. M. ( 1989) The development of applied Geometric method for measuring body surface action levels for soil contact: a scenario for the area: A height weight formula validated in infants, exposure of humans to soil in a residential setting. children, and adults. J. Ped. 93( 1): 62 66. Environ. Health Perspect. 79: 291 313. Holmes, K. K.; Kissel, J. C.; Richter, K. Y. ( 1996) Sendroy, J.; Cecchini, L. P. ( 1954) Determination of Investigation of the influence of oil on soil human body surface area from height and weight. J. adherence to skin. J. Soil Contam. 5( 4): 301 308. Appl. Physiol. 7( 1): 3 12. Kissel, J.; Richter, K.; Duff, R.; Fenske, R. ( 1996a) Factors Affecting Soil Adherence to Skin in Hand Press Trials. Bull. Environ. Contamin. Toxicol. 56: 722 728. Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 11 Thompson, K. M.; Burmaster, D. E. ( 1991) Parametric U. S. EPA. ( 1992b) Dermal exposure assessment: distributions for soil ingestion by children. Risk . principles and applications. Washington, DC: Anal. 11( 2): 339 342. Office of Research and Development, Office of U. S. EPA. ( 1985) Development of statistical Health and Environmental Assessment/ OHEA. U. S. distributions or ranges of standard factors used in EPA/ 600/ 8 9 91. exposure assessments. Washington, DC: Office Van Graan, C. H. ( 1969) The determination of body of Research and Development, Office of Health surface area. Supplement to the South African J. of and Environmental Assessment. EPA Lab. and Clin. Med. 8 2 69. 600/ 8 85 010. Available from: NTIS, Versar, Inc. ( 1991) Analysis of the impact of exposure Springfield, VA. PB85 242667. assumptions on risk assessment of chemicals in the U. S. EPA. ( 1989) Exposure factors handbook. environment, phase II: uncertainty analyses of Washington, DC: Office of Research and existing exposure assessment methods. Draft Development, Office of Health and Environmental Report. Prepared for Exposure Assessment Task Assessment. EPA/ 600/ 18 89/ 043. Group, Chemical Manufacturers Association, U. S. EPA. ( 1992a) Guidelines for exposure assessment. Washington, DC. Federal Register. FR 57: 104: 22888 22938. May Yang, J. J.; Roy, T. A.; Krueger, A. J.; Neil, W.; Mackerer, 29, 1992. C. R. ( 1989) In vitro and in vivo percutaneous absorption of benzo[ a] pyrene from petroleum crudefortified soil in the rat. Bull. Environ. Contam. Toxicol. 43: 207 214. Applied Dose Potential Dose Organ Chemical Effect Exposure Internal Dose Biologically Effective Dose Metabolism Skin Uptake Volume I  General Factors Chapter 6  Dermal Page Exposure Factors Handbook 6 12 August 1997 Figure 6 1. Schematic of Dose and Exposure: Dermal Route Source: U. S. EPA, 1992a.

Table 6 1. Summary of Equation Parameters for Calculating Adult Body Surface Area Body Part N P R S. E. Equation for surface areas ( m ) 2 2 a W H o a1 a2 Head Female 57 0.0256 0.124 0.189 0.01 0.302 0.00678 Male 32 0.0492 0.339  0.0950 0.01 0.222 0.0202 Trunk Female 57 0.188 0.647  0.304 0.001 0.877 0.00567 Male 32 0.0240 0.808  0.0131 0.001 0.894 0.0118 Upper Extremities Female 57 0.0288 0.341 0.175 0.001 0.526 0.00833 Male 48 0.00329 0.466 0.524 0.001 0.821 0.0101 Arms Female 13 0.00223 0.201 0.748 0.01 0.731 0.00996 Male 32 0.00111 0.616 0.561 0.001 0.892 0.0177 Upper Arms Male 6 8.70 0.741  1.40 0.25 0.576 0.0387 Forearms Male 6 0.326 0.858  0.895 0.05 0.897 0.0207 Hands Female 12 0.0131 0.412 0.0274 0.1 0.447 0.0172 Male 32 0.0257 0.573  0.218 0.001 0.575 0.0187 b Lower Extremities 105 0.00286 0.458 0.696 0.001 0.802 0.00633 c Legs 45 0.00240 0.542 0.626 0.001 0.780 0.0130 Thighs 45 0.00352 0.629 0.379 0.001 0.739 0.0149 Lower legs 45 0.000276 0.416 0.973 0.001 0.727 0.0149 Feet 45 0.000618 0.372 0.725 0.001 0.651 0.0147 SA = a W H a a1 a2 o W = Weight in kilograms; H = Height in centimeters; P = Level of significance; R = Coefficient of determination; 2 SA = Surface Area; S. E. = Standard error; N = Number of observations One observation for a female whose body weight exceeded the 95 percentile was not used. b Although two separate regressions were marginally indicated by the F test, pooling was done for consistency with individual components of c lower extremities. Source: U. S. EPA, 1985. Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 13 Table 6 2. Surface Area of Adult Males in Square Meters Percentile Body part 5 10 15 25 50 75 85 90 95 S. E. a Total 1.66 1.72 1.76 1.82 1.94 2.07 2.14 2.20 2.28 0.00374 Head 0.119 0.121 0.123 0.124 0.130 0.135 0.138 0.140 0.143 0.0202 Trunk 0.591 0.622 0.643 0.674 0.739 0.807 0.851 0.883 0.935 0.0118 b Upper extremities 0.321 0.332 0.340 0.350 0.372 0.395 0.408 0.418 0.432 0.00101 Arms 0.241 0.252 0.259 0.270 0.291 0.314 0.328 0.339 0.354 0.00387 Forearms 0.106 0.111 0.115 0.121 0.131 0.144 0.151 0.157 0.166 0.0207 Hands 0.085 0.088 0.090 0.093 0.099 0.105 0.109 0.112 0.117 0.0187 Lower extremities 0.653 0.676 0.692 0.715 0.761 0.810 0.838 0.858 0.888 0.00633 Legs 0.539 0.561 0.576 0.597 0.640 0.686 0.714 0.734 0.762 0.0130 Thighs 0.318 0.331 0.341 0.354 0.382 0.411 0.429 0.443 0.463 0.0149 Lower legs 0.218 0.226 0.232 0.240 0.256 0.272 0.282 0.288 0.299 0.0149 Feet 0.114 0.118 0.120 0.124 0.131 0.138 0.142 0.145 0.149 0.0147 c c c c c c c c c c c c c c c c c c c Standard error for the 5 95 percentile of each body part. a Trunk includes neck. b Percentile estimates exceed the maximum measured values upon which the equations are based. c Source: U. S. EPA, 1985.

Table 6 3. Surface Area of Adult Females in Square Meters Percentile Body part 5 10 15 25 50 75 85 90 95 S. E. a Total 1.45 1.49 1.53 1.58 1.69 1.82 1.91 1.98 2.09 0.00374 Head 0.106 0.107 0.108 0.109 0.111 0.113 0.114 0.115 0.117 0.00678 Trunk 0.490 0.507 0.518 0.538 0.579 0.636 0.677 0.704 0.752 0.00567 b Upper extremities 0.260 0.265 0.269 0.274 0.287 0.301 0.311 0.318 0.329 0.00833 Arms 0.210 0.214 0.217 0.221 0.230 0.238 0.243 0.247 0.253 0.00996 Hands 0.0730 0.0746 0.0757 0.0777 0.0817 0.0868 0.0903 0.0927 0.0966 0.0172 Lower extremities 0.564 0.582 0.595 0.615 0.657 0.704 0.736 0.757 0.796 0.00633 Legs 0.460 0.477 0.488 0.507 0.546 0.592 0.623 0.645 0.683 0.0130 Thighs 0.271 0.281 0.289 0.300 0.326 0.357 0.379 0.394 0.421 0.0149 Lower legs 0.186 0.192 0.197 0.204 0.218 0.233 0.243 0.249 0.261 0.0149 Feet 0.100 0.103 0.105 0.108 0.114 0.121 0.126 0.129 0.134 0.0147 c c c c c c c c c c c Standard error for the 5 95 percentile of each body part. a Trunk includes neck. b Percentile estimates exceed the maximum measured values upon which the equations are based. c Source: U. S. EPA, 1985. Volume I  General Factors Chapter 6  Dermal Page Exposure Factors Handbook 6 14 August 1997 Table 6 4. Surface Area by Body Part for Adults ( m ) 2 Body part Men Women N Mean ( sd) Min.  Max. N Mean ( sd) Min.  Max. a b Head 32 0.118 ( 0.0160) 0.090  0.161 57 0.110 ( 0.00625) 0.0953  0.127 Trunk 32 0.569 ( 0.104) 0.306  0.893 57 0.542 ( 0.0712) 0.437  0.867 ( Incl. Neck)

Upper extremities 48 0.319 ( 0.0461) 0.169  0.429 57 0.276 ( 0.0241) 0.215  0.333 Arms 32 0.228 ( 0.0374) 0.109  0.292 13 0.210 ( 0.0129) 0.193  0.235 Upper arms 6 0.143 ( 0.0143) 0.122  0.156       Forearms 6 0.114 ( 0.0127) 0.0945  0.136      Hands 32 0.084 ( 0.0127) 0.0596  0.113 12 0.0746 ( 0.00510) 0.0639 0.0824 Lower extremities 48 0.636 ( 0.0994) 0.283  0.868 57 0.626 ( 0.0675) 0.492  0.809 Legs 32 0.505 ( 0.0885) 0.221  0.656 13 0.488 ( 0.0515) 0.423  0.585 Thighs 32 0.198 ( 0.1470) 0.128  0.403 13 0.258 ( 0.0333) 0.258  0.360 Lower legs 32 0.207 ( 0.0379) 0.093  0.296 13 0.194 ( 0.0240) 0.165  0.229 Feet 32 0.112 ( 0.0177) 0.0611  0.156 13 0.0975 ( 0.00903) 0.0834  0.115 TOTAL 1.94 ( 0.00374) 1.66  2.28 1.69 ( 0.00374) 1.45  2.09 c d e c d e number of observations. a standard deviation. b median ( see Table 6 2). c standard error. d percentiles ( 5th  95th). e Source: Adapted from U. S. EPA, 1985.

Table 6 5. Percentage of Total Body Surface Area by Part for Adults Men Women Body part N Mean ( s. d.) Min.  Max. N Mean ( s. d.) Min.  Max. a b Head 32 7.8 ( 1.0) 6.1  10.6 57 7.1 ( 0.6) 5.6  8.1 Trunk 32 35.9 ( 2.1) 30.5  41.4 57 34.8 ( 1.9) 32.8  41.7 Upper extremities 48 18.8 ( 1.1) 16.4  21.0 57 17.9 ( 0.9) 15.6  19.9 Arms 32 14.1 ( 0.9) 12.5  15.5 13 14.0 ( 0.6) 12.4  14.8 Upper arms 6 7.4 ( 0.5) 6.7  8.1       Forearms 6 5.9 ( 0.3) 5.4  6.3      Hands 32 5.2 ( 0.5) 4.6  7.0 12 5.1 ( 0.3) 4.4 5.4 Lower extremities 48 37.5 ( 1.9) 33.3  41.2 57 40.3 ( 1.6) 36.0  43.2 Legs 32 31.2 ( 1.6) 26.1  33.4 13 32.4 ( 1.6) 29.8  35.3 Thighs 32 18.4 ( 1.2) 15.2  20.2 13 19.5 ( 1.1) 18.0  21.7 Lower legs 32 12.8 ( 1.0) 11.0  15.8 13 12.8 ( 1.0) 11.4  14.9 Feet 32 7.0 ( 0.5) 6.0  7.9 13 6.5 ( 0.3) 6.0  7.0 Number of observations. a Standard deviation. b Source: Adapted from U. S. EPA, 1985. Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 15 Table 6 6. Total Body Surface Area of Male Children in Square Metersa Age ( yr) b Percentile 5 10 15 25 50 75 85 90 95 2 < 3 0.527 0.544 0.552 0.569 0.603 0.629 0.643 0.661 0.682 3 < 4 0.585 0.606 0.620 0.636 0.664 0.700 0.719 0.729 0.764 4 < 5 0.633 0.658 0.673 0.689 0.731 0.771 0,796 0.809 0.845 5 < 6 0.692 0.721 0.732 0.746 0.793 0.840 0.864 0.895 0.918 6 < 7 0.757 0.788 0.809 0.821 0.866 0.915 0.957 1.01 1.06 7 < 8 0.794 0.832 0.848 0.877 0.936 0.993 1.01 1.06 1.11 8 < 9 0.836 0.897 0.914 0.932 1.00 1.06 1.12 1.17 1.24 9 < 10 0.932 0.966 0.988 1.00 1.07 1.13 1.16 1.25 1.29 10 < 11 1.01 1.04 1.06 1.10 1.18 1.28 1.35 1.40 1.48 11 < 12 1.00 1.06 1.12 1.16 1.23 1.40 1.47 1.53 1.60 12 < 13 1.11 1.13 1.20 1.25 1.34 1.47 1.52 1.62 1.76 13 < 14 1.20 1.24 1.27 1.30 1.47 1.62 1.67 1.75 1.81 14 < 15 1.33 1.39 1.45 1.51 1.61 1.73 1.78 1.84 1.91 15 < 16 1.45 1.49 1.52 1.60 1.70 1.79 1.84 1.90 2.02 16 < 17 1.55 1.59 1.61 1.66 1.76 1.87 1.98 2.03 2.16 17 < 18 1.54 1.56 1.62 1.69 1.80 1.91 1.96 2.03 2.09 3 < 6 0.616 0.636 0.649 0.673 0.728 0.785 0.817 0.842 0.876 6 < 9 0.787 0.814 0.834 0.866 0.931 1.01 1.05 1.09 1.14 9 < 12 0.972 1.00 1.02 1.07 1.16 1.28 1.36 1.42 1.52 12 < 15 1.19 1.24 1.27 1.32 1.49 1.64 1.73 1.77 1.85 15 < 18 1.50 1.55 1.59 1.65 1.75 1.86 1.94 2.01 2.11 Lack of height measurements for children < 2 years in NHANES II precluded calculation of surface areas for this age group. a Estimated values calculated using NHANES II data. b Source: U. S. EPA, 1985.

Table 6 7. Total Body Surface Area of Female Children in Square Metersa Percentile Age ( yr) 5 10 15 25 50 75 85 90 95 b 2 < 3 0.516 0.532 0.544 0.557 0.579 0.610 0.623 0.637 0.653 3 < 4 0.555 0.570 0.589 0.607 0.649 0.688 0.707 0.721 0.737 4 < 5 0.627 0.639 0.649 0.666 0.706 0.758 0.777 0.794 0.820 5 < 6 0.675 0.700 0.714 0.735 0.779 0.830 0.870 0.902 0.952 6 < 7 0.723 0.748 0.770 0.791 0.843 0.914 0.961 0.989 1.03 7 < 8 0.792 0.808 0.819 0.854 0.917 0.977 1.02 1.06 1.13 8 < 9 0.863 0.888 0.913 0.932 1.00 1.05 1.08 1.11 1.18 9 < 10 0.897 0.948 0.969 1.01 1.06 1.14 1.22 1.31 1.41 10 < 11 0.981 1.01 1.05 1.10 1.17 1.29 1.34 1.37 1.43 11 < 12 1.06 1.09 1.12 1.16 1.30 1.40 1.50 1.56 1.62 12 < 13 1.13 1.19 1.24 1.27 1.40 1.51 1.62 1.64 1.70 13 < 14 1.21 1.28 1.32 1.38 1.48 1.59 1.67 1.75 1.86 14 < 15 1.31 1.34 1.39 1.45 1.55 1.66 1.74 1.76 1.88 15 < 16 1.38 1.49 1.43 1.47 1.57 1.67 1.72 1.76 1.83 16 < 17 1.40 1.46 1.48 1.53 1.60 1.69 1.79 1.84 1.91 17 < 18 1.42 1.49 1.51 1.56 1.63 1.73 1.80 1.84 1.94 3 < 6 0.585 0.610 0.630 0.654 0.711 0.770 0.808 0.831 0.879 6 < 9 0.754 0.790 0.804 0.845 0.919 1.00 1.04 1.07 1.13 9 < 12 0.957 0.990 1.03 1.06 1.16 1.31 1.38 1.43 1.56 12 < 15 1.21 1.27 1.30 1.37 1.48 1.61 1.68 1.74 1.82 15 < 18 1.40 1.44 1.47 1.51 1.60 1.70 1.76 1.82 1.92 Lack of height measurements for children < 2 years in NHANES II precluded calculation of surface areas for this age group. a Estimated values calculated using NHANES II data. b Source: U. S. EPA, 1985. Volume I  General Factors Chapter 6  Dermal Page Exposure Factors Handbook 6 16 August 1997 Table 6 8. Percentage of Total Body Surface Area by Body Part for Children Age ( yr) N M: F Percent of Total Head Trunk Arms Hands Legs Feet Mean Min Max Mean Min Max Mean Min Max Mean Min Max Mean Min Max Mean Min Max < 1 2: 0 18.2 18.2 18.3 35.7 34.8 36.6 13.7 12.4 15.1 5.3 5.21 5.39 20.6 18.2 22.9 6.54 6.49 6.59 1 < 2 1: 1 16.5 16.5 16.5 35.5 34.5 36.6 13.0 12.8 13.1 5.68 5.57 5.78 23.1 22.1 24.0 6.27 5.84 6.70 2 < 3 1: 0 14.2 38.5 11.8 5.30 23.2 7.07 3 < 4 0: 5 13.6 13.3 14.0 31.9 29.9 32.8 14.4 14.2 14.7 6.07 5.83 6.32 26.8 26.0 28.6 7.21 6.80 7.88 4 < 5 1: 3 13.8 12.1 15.3 31.5 30.5 32.4 14.0 13.0 15.5 5.70 5.15 6.62 27.8 26.0 29.3 7.29 6.91 8.10 5 < 6 6 < 7 1: 0 13.1 35.1 13.1 4.71 27.1 6.90 7 < 8 8 < 9 9 < 10 0: 2 12.0 11.6 12.5 34.2 33.4 34.9 12.3 11.7 12.8 5.30 5.15 5.44 28.7 28.5 28.8 7.58 7.38 7.77 10 < 11 11 < 12 12 < 13 1: 0 8.74 34.7 13.7 5.39 30.5 7.03 13 < 14 1: 0 9.97 32.7 12.1 5.11 32.0 8.02 14 < 15 15 < 16 16 < 17 1: 0 7.96 32.7 13.1 5.68 33.6 6.93 17 < 18 1: 0 7.58 31.7 17.5 5.13 30.8 7.28 N: Number of subjects, male to female ratios.

Source: U. S. EPA 1985. Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 17 Table 6 9. Descriptive Statistics for Surface Area/ Body Weight ( SA/ BW) Ratios ( m / kg) 2 Age ( yrs.) Mean Min Max SD SE Range a b Percentiles 5 10 25 50 75 90 95 0 2 0.0641 0.0421 0.1142 0.0114 7.84e 4 0.0470 0.0507 0.0563 0.0617 0.0719 0.0784 0.0846 2.1  17.9 0.0423 0.0268 0.0670 0.0076 1.05e 3 0.0291 0.0328 0.0376 0.0422 0.0454 0.0501 0.0594 $ 18 0.0284 0.0200 0.0351 0.0028 7.68e 6 0.0238 0.0244 0.0270 0.0286 0.0302 0.0316 0.0329 All ages 0.0489 0.0200 0.1142 0.0187 9.33e 4 0.0253 0.0272 0.0299 0.0495 0.0631 0.0740 0.0788 Standard deviation. a Standard error of the mean. b Source: Phillips et al., 1993.

Table 6 10. Statistical Results for Total Body Surface Area Distributions ( m ) 2 Men U. S. EPA Boyd DuBois and DuBois Costeff Mean 1.97 1.95 1.94 1.89 Median 1.96 1.94 1.94 1.89 Mode 1.96 1.91 1.90 1.90 Standard Deviation 0.19 0.18 0.17 0.16 Skewness 0.27 0.26 0.23 0.04 Kurtosis 3.08 3.06 3.02 2.92 Women U. S. EPA Boyd DuBois and DuBois Costeff Mean 1.73 1.71 1.69 1.71 Median 1.69 1.68 1.67 1.68 Mode 1.68 1.62 1.60 1.66 Standard Deviation 0.21 0.20 0.18 0.21 Skewness 0.92 0.88 0.77 0.69 Kurtosis 4.30 4.21 4.01 3.52 Source: Murray and Burmaster, 1992 Volume I  General Factors Chapter 6  Dermal Page Exposure Factors Handbook 6 20 August 1997 Table 6 11. Summary of Field Studies Activity Month ( hrs) N M F Age Conditions Clothing Eventa b Indoor Tae Kwon Do Feb. 1.5 7 6 1 8 42 Carpeted floor All in longsleeve long pants martial arts uniform, sleeves rolled back, barefoot Greenhouse Workers Mar. 5.25 2 1 1 37 39 Plant watering, spraying, soil Long pants, elbow length short sleeve blending, sterilization shirt, no gloves Indoor Kids No. 1 Jan. 2 4 3 1 6 13 Playing on carpeted floor 3 of 4 short pants, 2 of 4 short sleeves, socks, no shoes Indoor Kids No. 2 Feb. 2 6 4 2 3 13 Playing on carpeted floor 5of 6 long pants, 5 of 6 long sleeves, socks, no shoes Indoor Totals 19 14 5 Outdoor Daycare Kids No. 1a Aug. 3.5 6 5 1 1 6.5 Indoors: linoleum surface; 4 of 6 in long pants, 4 of 6 short outdoors: grass, bare earth, barked sleeves, shoes area Daycare Kids No. 1b Aug. 4 6 5 1 1 6.5 Indoors: linoleum surface; 4 of 6 in long pants, 4 of 6 short outdoors: grass, bare earth, barked sleeves, no shoes area Daycare Kids No. 2c Sept. 8 5 4 1 1 4 Indoors, low napped carpeting, 4 of 5 long pants, 3of 5 long sleeves, linoleum surfaces all barefoot for part of the day Daycare Kids No. 3 Nov. 8 4 3 1 1 4.5 Indoors: linoleum surface, outside: All long pants, 3 of 4 long sleeves, grass, bare earth, barked area socks and shoes Soccer No. 1 Nov. 0.67 8 8 0 13 15 Half grass half bare earth 6 of 8 long sleeves, 4 of 8 long pants, 3 of 4 short pants and shin guards Soccer No. 2 Mar. 1.5 8 0 8 24 34 All weather field ( sand ground All in short sleeve shirts, shorts, knee tires) socks, shin guards Soccer No. 3 Nov. 1.5 7 0 7 24 34 All weather field ( sand ground All in short sleeve shirts, shorts, knee tires) socks, shin guards Groundskeepers No. 1 Mar. 1.5 2 1 1 29 52 Campus grounds, urban All in long pants, intermittent use of horticulture center, arboretum gloves Groundskeepers No. 2 Mar. 4.25 5 3 2 22 37 Campus grounds, urban horticulture All in long pants, intermittent use of center, arboretum gloves Groundskeepers No. 3 Mar. 8 7 5 2 30 62 Campus grounds, urban horticulture All in long pants, intermittent use of center, arboretum gloves Groundskeepers No. 4 Aug. 4.25 7 4 3 22 38 Campus grounds, urban horticulture 5 of 7 in short sleeve shirts, intermittent center, arboretum use of gloves Groundskeepers No. 5 Aug. 8 8 6 2 19 64 Campus grounds, urban horticulture 5 of 8 in short sleeve shirts, intermittent center, arboretum use of gloves Landscape/ Rockery June 9 4 3 1 27 43 Digging ( manual andmechanical), All long pants, 2 long sleeves, all socks rock moving and boots IrrigationInstallers Oct. 3 6 6 0 23 41 Landscaping, surface restoration All in long pants, 3 of 6 short sleeve or sleeveless shirts Gardeners No. 1 Aug. 4 8 1 7 16 35 Weeding, pruning, digging a trench 6 of 8 long pants, 7 of 8 short sleeves, 1 sleeveless, socks, shoes, intermittent use of gloves Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 21 Table 6 11. Summary of Field Studies ( continued)

Activity Month ( hrs) N M F Age Conditions Clothing Eventa b Gardeners No. 2 Aug. 4 7 2 5 26 52 Weeding, pruning, digging a 3 of 7 long pants, 5of 7 short sleeves, 1 trench, picking fruit, cleaning sleeveless, socks, shoes, no gloves Rugby No. 1 Mar. 1.75 8 8 0 20 22 Mixed grass barewet field All in short sleeve shirts, shorts, variable sock lengths Rugby No. 2 July 2 8 8 0 23 33 Grass field ( 80% oftime) and all All in shorts, 7 of 8 in short sleeve weather field ( mix of gravel, sand, shirts, 6 of 8 in low socks and clay) ( 20% oftime)

Rugby No. 3 Sept. 2.75 7 7 0 24 30 Compacted mixedgrass and bare All short pants, 7 of 8 short or rolled up earth field sleeves, socks, shoes Archeologists July 11.5 7 3 4 16 35 Digging withtrowel, screening dirt, 6 of 7 short pants, all short sleeves, 3 no sorting shoes or socks, 2 sandals Construction Workers Sept. 8 8 8 0 21 30 Mixed bare earth and concrete 5 of 8 pants, 7 of 8 short sleeves, all surfaces, dust and debris socks and shoes Utility Workers No. 1 July 9.5 5 5 0 24 45 Cleaning, fixing mains, excavation All long pants, short sleeves, socks, ( backhoe and shovel) boots, gloves sometimes Utility Workers No. 2 Aug. 9.5 6 6 0 23 44 Cleaning, fixing mains, excavation All long pants, 5 of 6 short sleeves, ( backhoe and shovel) socks, boots, gloves sometimes Equip. Operators No. 1 Aug. 8 4 4 0 21 54 Earth scraping withheavy All long pants, 3 of 4 short sleeves, machinery, dusty conditions socks, boots, 2 of 4 gloves Equip. Operators No. 2 Aug. 8 4 4 0 21 54 Earth scraping withheavy All long pants, 3 of 4 short sleeves, machinery, dusty conditions socks, boots, 1 gloves Farmers No. 1 May 2 4 2 2 39 44 Manual weeding, mechanical All in long pants, heavy shoes, short cultivation sleeve shirts, no gloves Farmers No. 2 July 2 6 4 2 18 43 Manual weeding, mechanical 2 of 6 short, 4 of 6long pants, 1 of 6 cultivation long sleeve shirt, no gloves Reed Gatherers Aug. 2 4 0 4 42 67 Tidal flats 2 of 4 shortsleeve shirts/ knee length pants, all wore shoes Kids in mud No. 1 Sept. 0.17 6 5 1 9 14 Lake shoreline All in short sleeve T shirts, shorts, barefoot Kids in mud No. 2 Sept. 0.33 6 5 1 9 14 Lake shoreline All in short sleeveT shirts, shorts, barefoot Outdoor Totals 181 125 56 a Event duration b Number of subject c Activities were confined to the house Sources: Kissel et al., 1996b; Holmes et al., 1996 ( submitted for publication). Volume I  General Factors Chapter 6  Dermal Page Exposure Factors Handbook 6 22 August 1997 Table 6 12. Geometric Mean and Geometric Standard Deviations of Soil Adherence by Activity and Body Region Post activity Dermal Soil Loadings ( mg/ cm2)

Activity N Hands Arms Legs Faces Feet a Indoor Tae Kwon Do 7 0.0063 0.0019 0.0020 0.0022 1.9 4.1 2.0 2.1 GreenhouseWorkers 2 0.043 0.0064 0.0015 0.0050

Indoor Kids No. 1 4 0.0073 0.0042 0.0041 0.012 1.9 1.9 2.3 1.4 Indoor Kids No. 2 6 0.014 0.0041 0.0031 0.0091 1.5 2.0 1.5 1.7 Daycare Kids No. 1a 6 0.11 0.026 0.030 0.079 1.9 1.9 1.7 2.4 Daycare Kids No. 1b 6 0.15 0.031 0.023 0.13 2.1 1.8 1.2 1.4 Daycare Kids No. 2 5 0.073 0.023 0.011 0.044 1.6 1.4 1.4 1.3 Daycare Kids No. 3 4 0.036 0.012 0.014 0.0053 1.3 1.2 3.0 5.1 Outdoor Soccer No. 1 8 0.11 0.011 0.031 0.012 1.8 2.0 3.8 1.5 Soccer No. 2 8 0.035 0.0043 0.014 0.016 3.9 2.2 5.3 1.5 Soccer No. 3 7 0.019 0.0029 0.0081 0.012 1.5 2.2 1.6 1.6 Groundskeepers No. 1 2 0.15 0.005 0.0021 0.018

Groundskeepers No. 2 5 0.098 0.0021 0.0010 0.010 2.1 2.6 1.5 2.0 Groundskeepers No. 3 7 0.030 0.0022 0.0009 0.0044 0.0040 2.3 1.9 1.8 2.6 Groundskeepers No. 4 7 0.045 0.014 0.0008 0.0026 0.018 1.9 1.8 1.9 1.6

Groundskeepers No. 5 8 0.032 0.022 0.0010 0.0039 1.7 2.8 1.4 2.1 Landscape/ Rockery 4 0.072 0.030 0.0057 2.1 2.1 1.9 Irrigation Installers 6 0.19 0.018 0.0054 0.0063 1.6 3.2 1.8 1.3 Gardeners No. 1 8 0.20 0.050 0.072 0.058 0.17 1.9 2.1  1.6  Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 23 Table 6 12. Geometric Mean and Geometric Standard Deviations of Soil Adherence by Activity and Body Region ( continued) Post activity Dermal Soil Loadings ( mg/ cm2) Activity N Hands Arms Legs Faces Feet a Gardeners No. 2 7 0.18 0.054 0.022 0.047 0.26 3.4 2.9 2.0 1.6

Rugby No. 1 8 0.40 0.27 0.36 0.059 1.7 1.6 1.7 2.7 Rugby No. 2 8 0.14 0.11 0.15 0.046 1.4 1.6 1.6 1.4 Rugby No. 3 7 0.049 0.031 0.057 0.020 1.7 1.3 1.2 1.5 Archeologists 7 0.14 0.041 0.028 0.050 0.24 1.3 1.9 4.1 1.8 1.4 Construction Workers 8 0.24 0.098 0.066 0.029 1.5 1.5 1.4 1.6 Utility Workers No. 1 5 0.32 0.20 0.10 1.7 2.7 1.5 Utility Workers No. 2 6 0.27 0.30 0.10 2.1 1.8 1.5 Equip. Operators No. 1 4 0.26 0.089 0.10 2.5 1.6 1.4 Equip. Operators No. 2 4 0.32 0.27 0.23 1.6 1.4 1.7 Farmers No. 1 4 0.41 0.059 0.0058 0.018 1.6 3.2 2.7 1.4 Farmers No. 2 6 0.47 0.13 0.037 0.041 1.4 2.2 3.9 3.0 Reed Gatherers 4 0.66 0.036 0.16 0.63 1.8 2.1 9.2 7.1 Kids in mud No. 1 6 35 11 36 24 2.3 6.1 2.0 3.6 Kids in mud No. 2 6 58 11 9.5 6.7 2.3 3.8 2.3 12.4 Number of subjects. a Sources: Kissel et al., 1996b; Holmes et al., 1996 ( submitted for publication). Volume I  General Factors Chapter 6  Dermal Page Exposure Factors Handbook 6 24 August 1997 Table 6 13. Summary of Surface Area Studies Surface Area Study No. of Individuals Type of Surface Area Measurement Recommended Formulae Used Population Surveyed Comments KEY STUDIES Phillips et al. ( 1993) Based on data from U. S.

EPA ( 1985): 401 individuals NA calculated surface area to body weight ratios Children Adults Developed distributions of SA/ BW and calculated summary statistics for 3 age groups and the combined data set U. S. EPA ( 1985) 401 individuals Based on Gehan and George ( 1970) SA= 0.0239* W * H 0.517 0.417 Children Adults Provides statistical distribution data for total SA and SA of body parts RELEVANT STUDIES AICH ( 1994) Based on data from U. S.

EPA ( 1989); Brainard et al. ( 1991); Brorby and Finley ( 1993) @ Risk simulation software Various Adults Children Distribution data for: adult men and women and both sexes combined; total skin area,

children 8 18 years; exposed skin area ( hands and forearms); head;

upper body Murray and Burmaster ( 1992) Based on data from U. S.

EPA ( 1985): N = 401;

Dubois and Dubois ( 1976): N = 9;

Boyd ( 1935): N = 231;

Costeff ( 1966): N = 220 Calculated based on regression equation using the data of U. S. EPA ( 1985) Various Children Adults Analysis of and comparision of four models developed by Dubois & Dubois ( 1916), Boyd ( 1935), U. S. EPA ( 1985), and Costeff ( 1966). Presents frequency distribtions Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 25 Table 6 14. Summary of Recommended Values for Skin Surface Area Surface Area Central Tendency Upper Percentile Multiple Percentiles Adults Whole body and body see Tables 6 4 and 6 5 see Tables 6 2 and 6 3 see Tables 6 2 and 6 3 parts Bathing/ swimming 20,000 cm 23,000 cm  2 2 Outdoor soil contact 5,000 cm 5,800 cm  2 2 Children Whole body  see Tables 6 6 and 6 7 see Tables 6 6 and 6 7 Body parts  see Table 6 8 see Table 6 8 Table 6 15. Confidence in Body Surface Area Measurement Recommendations Considerations Rationale Rating Study Elements ° Level of Peer Review Studies were from peer reviewed journal articles. High EPA report was peer reviewed before distribution.

° Accessibility The journals used have wide circulation. High EPA report available from National Technical Information Service.

° Reproducibility Experimental methods are well described. High ° Focus on factor of interest Experiments measured skin area directly. High ° Data pertinent to U. S. Experiments conducted in the U. S. High ° Primary data Re analysis of primary data in more detail by two different Low investigators .

° Currency Neither rapidly changing nor controversial area; estimates Low made in 1935 deemed to be accurate and subsequently used by others.

° Adequacy of data collection Not relevant to exposure factor; parameter not time NA period dependent.

° Validity of approach Approach used by other investigators; not challenged in other High studies.

° Representativeness of the Not statistically representative of U. S. population. Medium population ° Characterization of variability Individual variability due to age, race, or gender not studied. Low ° Lack of bias in study design Objective subject selection and measurement methods used; High results reproduced by others with different methods.

° Measurement error Measurement variations are low; adequately described by Low/ Medium normal statistics.

Other Elements ° Number of studies 1 experiment; two independent re analyses of this data set. Medium ° Agreement among researchers Consistent results obtained with different analyses; but from Medium a single set of measurements.

Overall Rating This factor can be directly measured. It is not subject to High dispute. Influence of age, race, or gender have not been detailed adequately in these studies. Volume I  General Factors Chapter 6  Dermal Page Exposure Factors Handbook 6 26 August 1997 Table 6 16. Recommendations for Adult Body Surface Area Water Contact 50th 95th Bathing and Swimming 20,000 cm 23,000 cm 2 2 Soil Contact 50th 95th Outdoor Activities 5,000 cm 5,800 cm 2 2 Source: U. S. EPA, 1992.

Table 6 17. Summary of Soil Adherence Studies Study ( F m) Adherence Surveyed Comments Size Fraction Soil Population ( mg/ cm ) 2 KEY STUDIES Kissel et al., 1995a < 150, 150 Various 28 adults Data presented for soil loadings by body 200, > 250 24 children part. See Table 6 11.

Kissell et al., 1996b  Various 12 children Data presented by activity and body 89 adults part.

RELEVANT STUDIES Driver et al., 1989 < 150 1.40 Adults Used 5 soil types and 2 3 soil horizons < 250 0.95 Adults ( top soils and subsoils); placed soil over unsieved 0.58 Adults entire hand of test subject, excess removed by shaking the hands.

Lepow et al., 1975  0.5 10 children Dirt from hands collected during play. Represents only fraction of total present, some dirt may be trapped in skin folds.

Que Hee et al., 1985  1.5 1 adult Assumed exposed area = 20 cm . Test 2 subject was 14 years old.

Roels et al., 1980  0.9 1.5 661 children Subjects lived near smelter in Brussels, Belgium. Mean amount adhering to soil was 0.159 g.

Sedman, 1989  0.9; 0.5 Children Used estimate of Roels et al. ( 1980) and average surface of hand of an 11 year old; used estimates of Lepow et al. ( 1975), Roels et al. ( 1980), and Que Hee et al. ( 1985) to develop mean of 0.5 mg/ cm . 2 Yang et al., 1989 < 150 9 Rats Rat skin " monolayer" ( i. e., minimal amount of soil covering the skin); in vitro and in vivo experiments. Volume I  General Factors Chapter 6  Dermal Exposure Factors Handbook Page August 1997 6 27 Table 6 18. Confidence in Soil Adherence to Skin Recommendations Considerations Rationale Rating Study Elements ° Level of Peer Review Studies were from peer reviewed journal articles. High ° Accessibility Articles were published in widely circulated journals. High ° Reproducibility Reports clearly describe experimental method. High ° Focus on factor of interest The goal of the studies was to determine soil adherence to High skin.

° Data pertinent to U. S. Experiments were conducted in the U. S. High ° Primary data Experiments were directly measure soil adherence to skin; High exposure and dose of chemicals in soil were measured indirectly or estimated from soil contact.

° Currency New studies were presented. High ° Adequacy of data collection Seasonal factors may be important, but have not been studied Medium period adequately.

° Validity of approach Skin rinsing technique is a widely employed procedure. High ° Representativeness of the Studies were limited to the State of Washington and may not Low population be representative of other locales.

° Characterization of variability Variability in soil adherence is affected by many factors Low including soil properties, activity and individual behavior patterns.

° Lack of bias in study design The studies attempted to measure soil adherence in selected High activities and conditions to identify important activities and groups.

° Measurement error The experimental error is low and well controlled, but Low/ High application of results to other similar activities may be subject to variation.

Other Elements ° Number of studies The experiments were controlled as they were conducted by Medium a few laboratories; activity patterns were studied by only one laboratory.

° Agreement among researchers Results from key study were consistent with earlier estimates Medium from relevant studies and assumptions, but are limited to hand data.

Overall Rating Data are limited, therefore it is difficult to extrapolate from Low experiments and field observations to general conditions . Volume I  General Factors Appendix 6A Exposure Factors Handbook Page August 1997 6A 1 APPENDIX 6A FORMULAE FOR TOTAL BODY SURFACE AREA SA ' a 0 H a1 W a2 Volume I  General Factors Appendix 6A Exposure Factors Handbook Page August 1997 6A 3 ( Eqn. 6A 2) APPENDIX 6A FORMULAE FOR TOTAL BODY SURFACE AREA Most formulae for estimating surface area ( SA), relate height to weight to surface area. The following formula was proposed by Gehan and George ( 1970):

SA = KW ( Eqn. 6A 1) 2/ 3 where:

SA = surface area in square meters; W = weight in kg; and K = constant.

While the above equation has been criticized because human bodies have different specific gravities and because the surface area per unit volume differs for individuals with different body builds, it gives a reasonably good estimate of surface area.

A formula published in 1916 that still finds wide acceptance and use is that of DuBois and DuBois. Their model can be written:

where:

SA = surface area in square meters; H = height in centimeters; and W = weight in kg.

The values of a ( 0.007182), a ( 0.725), and a ( 0.425) were estimated from a sample of only nine individuals for 0 1 2 whom surface area was directly measured. Boyd ( 1935) stated that the Dubois formula was considered a reasonably adequate substitute for measuring surface area. Nomograms for determining surface area from height and mass presented in Volume I of the Geigy Scientific Tables ( 1981) are based on the DuBois and DuBois formula. In addition, a computerized literature search conducted for this report identified several articles written in the last 10 years in which the DuBois and DuBois formula was used to estimate body surface area.

Boyd ( 1935) developed new constants for the DuBois and DuBois model based on 231 direct measurements of body surface area found in the literature. These data were limited to measurements of surface area by coating methods ( 122 cases), surface integration ( 93 cases), and triangulation ( 16 cases). The subjects were Caucasians of normal body build for whom data on weight, height, and age ( except for exact age of adults) were complete. Resulting values for the constants in the DuBois and DuBois model were a = 0.01787, a = 0.500, and a = 0.4838. Boyd also developed a formula based 0 1 2 exclusively on weight, which was inferior to the DuBois and DuBois formula based on height and weight. Volume I  General Factors Appendix 6A Page Exposure Factors Handbook 6A 4 August 1997 Gehan and George ( 1970) proposed another set of constants for the DuBois and DuBois model. The constants were based on a total of 401 direct measurements of surface area, height, and weight of all postnatal subjects listed in Boyd ( 1935). The methods used to measure these subjects were coating ( 163 cases), surface integration ( 222 cases), and triangulation ( 16 cases).

Gehan and George ( 1970) used a least squares method to identify the values of the constants. The values of the constants chosen are those that minimize the sum of the squared percentage errors of the predicted values of surface area. This approach was used because the importance of an error of 0.1 square meter depends on the surface area of the individual. Gehan and George ( 1970) used the 401 observations summarized in Boyd ( 1935) in the least squares method. The following estimates of the constants were obtained: a = 0.02350, a = 0.42246, and a = 0.51456. Hence, their equation 0 1 2 for predicting surface area ( SA) is:

SA = 0.02350 H W ( Eqn. 6A 3) 0.42246 0.51456 or in logarithmic form:

ln SA=  3.75080 + 0.42246 ln H + 0.51456 ln W ( Eqn. 6A 4)

where:

SA = surface area in square meters; H = height in centimeters; and W = weight in kg.

This prediction explains more than 99 percent of the variations in surface area among the 401 individuals measured ( Gehan and George, 1970).

The equation proposed by Gehan and George ( 1970) was determined by the U. S. EPA ( 1985) as the best choice for estimating total body surface area. However, the paper by Gehan and George gave insufficient information to estimate the standard error about the regression. Therefore, the 401 direct measurements of children and adults ( i. e., Boyd, 1935) were reanalyzed in U. S. EPA ( 1985) using the formula of Dubois and Dubois ( 1916) and the Statistical Processing System ( SPS) software package to obtain the standard error.

The Dubois and Dubois ( 1916) formula uses weight and height as independent variables to predict total body surface area ( SA), and can be written as:

SA = a H W e ( Eqn. 6A 5) i 0 i i i a1 a2 or in logarithmic form:

ln ( SA) = ln a + a ln H + a ln W + ln e ( Eqn. 6A 6) i 0 l i 2 i i where:

Sai = surface area of the i th individual ( m ); 2 Hi = height of the i th individual ( cm); Wi = weight of the i th individual ( kg); a , a , and a = parameters to be estimated; and 0 1 2 e = a random error term with mean zero and constant variance. i Volume I  General Factors Appendix 6A Exposure Factors Handbook Page August 1997 6A 5 Using the least squares procedure for the 401 observations, the following parameter estimates and their standard errors were obtained:

a =  3.73 ( 0.18), a = 0.417 ( 0.054), a = 0.517 ( 0.022) 0 1 2 The model is then:

SA = 0.0239 H W ( Eqn. 6A 7) 0.417 0.517 or in logarithmic form:

ln SA =  3.73 + 0.417 ln H + 0.517 ln W ( Eqn. 6A 8)

with a standard error about the regression of 0.00374. This model explains more than 99 percent of the total variation in surface area among the observations, and is identical to two significant figures with the model developed by Gehan and George ( 1970).

When natural logarithms of the measured surface areas are plotted against natural logarithms of the surface predicted by the equation, the observed surface areas are symmetrically distributed around a line of perfect fit, with only a few large percentage deviations. Only five subjects differed from the measured value by 25 percent or more. Because each of the five subjects weighed less than 13 pounds, the amount of difference was small. Eighteen estimates differed from measurements by 15 to 24 percent. Of these, 12 weighed less than 15 pounds each, 1 was overweight ( 5 feet 7 inches, 172 pounds), 1 was very thin ( 4 feet 11 inches, 78 pounds), and 4 were of average build. Since the same observer measured surface area for these 4 subjects, the possibility of some bias in measured values cannot be discounted ( Gehan and George 1970).

Gehan and George ( 1970) also considered separate constants for different age groups: less than 5 years old, 5 years old to less than 20 years old, and greater than 20 years old. The different values for the constants are presented below:

Table 6A 1. Estimated Parameter Values for Different Age Intervals Age Number a a a 0 1 2 group of persons All ages 401 0.02350 0.42246 0.51456 < 5 years old 229 0.02667 0.38217 0.53937 $ 5  < 20 years old 42 0.03050 0.35129 0.54375 $ 20 years old1 30 0.01545 0.54468 0.46336 The surface areas estimated using the parameter values for all ages were compared to surface areas estimated by the values for each age group for subjects at the 3rd, 50th, and 97th percentiles of weight and height. Nearly all differences in surface area estimates were less than 0.01 square meter, and the largest difference was 0.03 m for an 18 year old at the 2 97th percentile. The authors concluded that there is no advantage in using separate values of a , a , and a by age interval. 0 1 2 Volume I  General Factors Appendix 6A Page Exposure Factors Handbook 6A 6 August 1997 Haycock et al. ( 1978) without knowledge of the work by Gehan and George ( 1970), developed values for the parameters a , a , and a for the DuBois and DuBois model. Their interest in making the DuBois and DuBois model more 0 1 2 accurate resulted from their work in pediatrics and the fact that DuBois and DuBois ( 1916) included only one child in their study group, a severely undernourished girl who weighed only 13.8 pounds at age 21 months. Haycock et al. ( 1978) used their own geometric method for estimating surface area from 34 body measurements for 81 subjects. Their study included newborn infants ( 10 cases), infants ( 12 cases), children ( 40 cases), and adult members of the medical and secretarial staffs of 2 hospitals ( 19 cases). The subjects all had grossly normal body structure, but the sample included subjects of widely varying physique ranging from thin to obese. Black, Hispanic, and white children were included in their sample. The values of the model parameters were solved for the relationship between surface area and height and weight by multiple regression analysis. The least squares best fit for this equation yielded the following values for the three coefficients: a = 0.024265, 0 a = 0.3964, and a = 0.5378. The result was the following equation for estimating surface area: 1 2 SA = 0.024265 H W ( Eqn. 6A 9) 0.3964 0.5378 expressed logarithmically as:

ln SA = ln 0.024265 + 0.3964 ln H + 0.5378 ln W ( Eqn. 6A 10)

The coefficients for this equation agree remarkably with those obtained by Gehan and George ( 1970) for 401 measurements.

George et al. ( 1979) agree that a model more complex than the model of DuBois and DuBois for estimating surface area is unnecessary. Based on samples of direct measurements by Boyd ( 1935) and Gehan and George ( 1970), and samples of geometric estimates by Haycock et al. ( 1978), these authors have obtained parameters for the DuBois and DuBois model that are different than those originally postulated in 1916. The DuBois and DuBois model can be written logarithmically as:

ln SA = ln a + a ln H + a ln W ( Eqn. 6A 11) 0 1 2 The values for a , a , and a obtained by the various authors discussed in this section are presented to follow: 0 1 2 Table 6A 2. Summary of Surface Area Parameter Values for the DuBois and DuBois Model Author Number a a a 0 1 2 ( year) of persons DuBois and DuBois ( 1916) 9 0.007184 0.725 0.425 Boyd ( 1935) 231 0.01787 0.500 0.4838 Gehan and George ( 1970) 401 0.02350 0.42246 0.51456 Haycock et al. ( 1978) 81 0.024265 0.3964 0.5378 The agreement between the model parameters estimated by Gehan and George ( 1970) and Haycock et al. ( 1978) is remarkable in view of the fact that Haycock et al. ( 1978) were unaware of the previous work. Haycock et al. ( 1978) used an entirely different set of subjects, and used geometric estimates of surface area rather than direct measurements. It has been determined that the Gehan and George model is the formula of choice for estimating total surface area of the body since it is based on the largest number of direct measurements. Volume I  General Factors Appendix 6A Exposure Factors Handbook Page August 1997 6A 7 Nomograms Sendroy and Cecchini ( 1954) proposed a graphical method whereby surface area could be read from a diagram relating height and weight to surface area. However, they do not give an explicit model for calculating surface area. The graph was developed empirically based on 252 cases, 127 of which were from the 401 direct measurements reported by Boyd ( 1935). In the other 125 cases the surface area was estimated using the linear method of DuBois and DuBois ( 1916). Because the Sendroy and Cecchini method is graphical, it is inherently less precise and less accurate than the formulae of other authors discussed above.


[Federal Register Volume 81, Number 94 (Monday, May 16, 2016)]
[Proposed Rules]
[Pages 30218-30219]
[FR Doc No: 2016-11455]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 93

[Docket No.: FAA-2014-1073; Notice No. 16-03]
RIN 2120-AJ89

Slot Management and Transparency for LaGuardia Airport, John F.
Kennedy International Airport, and Newark Liberty International Airport

AGENCY: Federal Aviation Administration (FAA), U.S. Department of
Transportation (DOT).

ACTION: Notice of proposed rulemaking; withdrawal.

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SUMMARY: The DOT is withdrawing a previously published Notice of
Proposed Rulemaking (NPRM) that would have replaced the Orders limiting
scheduled operations at John F. Kennedy International Airport (JFK),
Newark Liberty International Airport (EWR), and LaGuardia Airport (LGA)

with longer-term limits on scheduled and unscheduled operations at JFK,
EWR, and LGA, and requested comment on options to establish a secondary
market for the purchase, sale, lease, or trade of slots at these
airports, as well as procedures that would codify the review of slot
transactions arising from the secondary market for public interest and
anti-competitive effects.

DATES: As of May 16, 2016, the NPRM published on January 8, 2015 (80 FR
1274) is withdrawn.

SUPPLEMENTARY INFORMATION: In 2006, the FAA issued an Order imposing
temporary limits on operations at LGA (71 FR 77854), and in 2008,
issued Orders imposing temporary limits on operations at JFK (73 FR
3510) and EWR (73 FR 29550). These Orders have been extended and are in
effect until October 29, 2016. On April 6, 2016, the FAA announced that
the current Order at EWR will expire on October 29, 2016, and that EWR
will be a Level 2, schedule-facilitated airport under the Worldwide
Slot Guidelines effective for the Winter 2016 scheduling season (81 FR
19861). By this same announcement, the FAA indicated that slot-
controlled restrictions at JFK and LGA remain necessary and that the
FAA will extend these Orders, by separate Federal Register notices,
until October 27, 2018.
    On January 8, 2015, the FAA and DOT published an NPRM (80 FR 1274)
that would replace the FAA's Orders limiting scheduled operations at
JFK, EWR, and LGA with a long-term comprehensive approach to slot
management at these airports. The NPRM proposed the continuation of the
limits on scheduled and unscheduled operations in place at each of
these airports under the Orders, and would have required use of an
allocated slot 80% of the time for the same flight or series of
flights. The NPRM also requested public comment about five alternatives
for a secondary market for the purchase, sale, lease, or trade of slots
and proposed procedures to codify the exercise of DOT's existing
authority to review slot transactions for anti-competitive and public
interest effects arising from those secondary market transactions that
would have been permitted by the implementation of a bulletin board for
the proposed secondary market.
    Since the FAA and DOT first initiated this rulemaking effort there
have been significant changes in circumstances affecting New York City
area airports, including changes in competitive effects from ongoing
industry consolidation, slot utilization and transfer behavior, and
actual operational performance at the three airports. Furthermore, the
FAA recently announced that slot controls are no longer needed at EWR
(81 FR 19861). The NPRM proposed an approach to manage slots and the
efficient use of airspace at JFK, EWR, and LGA that would have treated
all three New York City area airports similarly. In light of the
changes in market conditions and operational performance, and
particularly the potential impact of EWR's change in status, the
Department is withdrawing the NPRM to allow for further evaluation of
these changes. Withdrawal of this NPRM (80 FR 1274, January 8, 2015)
does not preclude the agency from issuing future rulemakings on this
issue, nor does it commit the agency to any course of action in the
future. The FAA will continue to monitor the operational performance at
these airports. Further, if the Department detects unfair or
anticompetitive behavior, we will not hesitate to continue to use our
existing authority to take corrective action. We will also continue to
cooperate with the U.S. Department of Justice on any reviews it
undertakes.
    Issued under authority provided by 49 U.S.C. 106(f), 40101, 40103,
40105, and 41712 in Washington, DC on May 6, 2016.

Jenny T. Rosenberg,
Acting Assistant Secretary for Aviation and International Affairs.
Nan Shellabarger,
Acting Assistant Administrator for Policy, International Affairs, and
Environment.
[FR Doc. 2016-11455 Filed 5-13-16; 8:45 am]
BILLING CODE 4910-13-P