Appendix A Data Inputs for Phase II Groundwater Modeling This page intentionally left blank. Appendix A Data Inputs for Phase II Groundwater Modeling A 3 Appendix A Data Inputs for Phase II Groundwater Modeling This appendix documents the inputs used in the groundwater modeling. In addition, Attachment A. 1 provides additional methodological details for IWEM. Note that Attachment A. 1 is a memo with its own attachments A and B; for clarity, those attachments are labeled as " Memo Attachment A" and " Memo Attachment B."

A. 1 Scenarios Table A 1 summarizes the source scenarios modeled. For nonaerated units, EPA did one central tendency run, in which all WATER9 inputs were set to central tendency values, and four high end runs, in which two of the most critical inputs were set to high end values. All other inputs, including all waste parameters, were set to central tendency values for all runs. The most sensitive parameters for nonaerated units are biomass, flow, capacity, and solids removal efficiency ( fraction of diverted flow that is solids).

For the aerated treatment train, biomass was not varied because a very low value would not be realistic, because such treatment trains are designed to support the growth of biomass. Solids parameters are not an input to the aerated treatment train units in WATER9. Thus, there were only two critical parameters for the aerated treatment train: flow and residence time. EPA did one central tendency run and two high end runs, with one of these two critical parameters set to high end for each run.

Table A 1. Summary of Source Scenarios Modeled Component Scenario Nonaerated Units Aerated Treatment Train 1 2 3 4 5 7 8 9 Biomass high central high central high not varied not varied not varied Flow central central high high central central high central Capacity/ residence time high central central high central central central high Solids central central central central high NA NA NA Appendix A Data Inputs for Phase II Groundwater Modeling A 4 A. 2 Source Inputs A. 2.1 Data Sources EPA used four primary sources of data:

# BRS database   waste flows # SIS survey database   unit characteristics for surface impoundments and waste characteristics # Tanks database ( U. S. EPA, 1987)   unit characteristics for tanks # WATER9 default values   parameters not available from the other sources.

The BRS data are the data reported by facilities to EPA on quantities of hazardous wastes managed. EPA pulled BRS data on waste volumes by facility and by waste stream of the F002 and F005 waste streams being considered for exemption. For the risk modeling, EPA used the facility level data, assuming that most facilities would combine these small waste streams for treatment or storage.

The SIS survey database ( U. S. EPA, 2001) is the most comprehensive available data set on Subtitle D ( nonhazardous) surface impoundments. Although the universe of impoundments in the database was sampled specifically for SIS in scope impoundments, the database has undergone extensive quality assurance checks and is being used in other Office of Solid Waste ( OSW) work. In using the SIS survey data, EPA limited the universe to impoundments that manage at least one organic chemical ( not necessarily one of the three analyzed in this assessment). EPA has taken this approach before ( most recently to assess default values for the Industrial Waste Air Model ( IWAIR)) to weed out impoundments managing only inorganics, which tend to be rather different than those that manage organics. EPA pulled the data needed and calculated weighted medians for each parameter, using the survey weights. The SIS data include volume, flow, area, depth, and most of the needed waste characteristics.

The Tanks database was developed for the Air Characteristic Study and also used for the Paints listing ( RTI, 2001). The database is based on EPA's National Survey of Hazardous Waste Treatment, Storage, Disposal, and Recycling Facilities ( TSDR) survey ( U. S. EPA, 1987) and, therefore, reflects hazardous waste units rather than Subtitle D facilities. However, EPA believes these are the only data currently available for characterizing tanks. The Tanks database does not have associated weights, so those data were used unweighted. The database contains data on the volume of the tank and the quantity of hazardous and nonhazardous waste managed. The Tanks database does not contain data on area or depth. It also does not include waste characteristic data; therefore, we used the SIS data to characterize the waste, on the assumption that the waste streams are similar regardless of whether they are managed in a tank or a surface impoundment. Appendix A Data Inputs for Phase II Groundwater Modeling A 5 The WATER9 default values are based on engineering principles and were used in this analysis only for parameters to which the model is not highly sensitive, when data were not readily available from other sources.

A. 2.2 Unit Characterization A. 2.2.1 Nonaerated units. Many of the parameters used in WATER9 are interrelated and cannot be set independently without producing an inconsistent data set. For example, a very large waste volume would not be likely to be managed in a very small unit. Similarly, volume of the unit and dimensions, such as area and depth, are related but not to the degree of having a fixed mathematical relationship. The goal was to choose, for each scenario, a set of inputs that was internally consistent and plausible.

EPA started with a flow equal to a waste quantity corresponding to central tendency and high end percentiles from the BRS survey data and then sized the units accordingly, using data from the other data sources. This approach reflects the assumption that the exempted waste is the only waste managed in the modeled unit; if other wastes were co managed, the flow through the unit would be greater than the waste quantity of the exempted waste stream, and the unit would be commensurately larger. The flows from the BRS data, even at the high end of the distribution, are relatively small flows from the perspective of wastewater treatment. Thus, they may be combined with other wastes. However, for nonaerated units, even small waste streams may be managed separately. Therefore, EPA assumed that the potentially exempted waste constitutes all of the flow to the nonaerated units modeled.

Starting with flow, EPA characterized the units using the following steps:

1. Flow. EPA chose a flow based on the facility level waste quantity data from the BRS, using the median for a central tendency value and the 90th percentile for a high end value.

2. Volume. Using the unweighted SIS data, EPA selected a subset of about 10 impoundments with flows similar to the flows selected in Step 1 for central tendency and high end. Using those impoundments, EPA identified a range of volumes associated with the flow; EPA used the central volume when setting volume to a central tendency value and the lowest volume when setting volume to a high end value. EPA took the same approach with the tanks data to select corresponding volumes for tanks.

3. Depth and Area. EPA performed a regression to relate area to volume for the SIS data. A similar regression relating depth to volume had already been done with the tanks data for the Air Characteristic Study. EPA used these regressions to estimate a reasonable depth or area for the selected volume. EPA calculated the remaining parameter ( area or depth) by dividing volume by depth or area.

4. Length, Width, or Diameter. For impoundments, EPA calculated length and width from area by assuming the unit is square. For tanks, EPA calculated diameter from area by assuming the tank is circular. Appendix A Data Inputs for Phase II Groundwater Modeling A 6 To set values for the solids diversion parameters for WATER9, EPA used data on solids removal efficiencies and the percentage of diverted sludge that is solids from the SIS survey and calculated the inputs needed for WATER9 from these.

A. 2.2.2 Aerated treatment train. Like the nonaerated units, many of the inputs to WATER9 for the aerated treatment train are interrelated. In the case of the aerated treatment train, there is also the added complexity that such treatment trains are rarely sized for a waste stream as small as even the 90th percentile F002/ F005 waste stream from the BRS data. The presence of an aerator in the activated sludge unit, for example, places certain limitations on the volume of the unit. Similarly, flows and residence times must be sufficient to maintain the biomass in the activated sludge unit   there must be enough chemical mass as food to feed the biomass or it will die off.

The aerated treatment train units were sized by taking the 50th and 90th percentile flows from the BRS data as a starting point, as was done for nonaerated units. Then, using typical ranges of retention time for activated sludge systems, EPA selected a central tendency residence time and a high end residence time. Using the flow and the residence time for a particular scenario, the capacities of the three units ( primary clarifier, activated sludge unit, and secondary clarifier) were estimated. The capacities consider the influent flow ( from the BRS data), as well as recycle flow from the secondary clarifier to the activated sludge unit.

In sizing the units, EPA determined that the central tendency flow from the BRS data resulted in unit capacities that were too small to be feasible given good engineering design principles. Therefore, for central tendency flow, EPA used the smallest flow that resulted in feasible unit capacities. That flow is about the 75th percentile of the BRS data.

It should be noted that the units sized for both 75th percentile flow and 90th percentile flow are still extremely small and are not likely to be typical of actual treatment systems of this type. These systems are small enough that operating such a system would require feeding the biomass because there would be insufficient chemical mass to maintain optimal biomass levels for biodegradation. Real systems are likely to be considerably larger and combine smaller waste streams into one large flow. However, WATER9 is not highly sensitive to the unit capacity and flow for aerated treatment trains designed for biodegradation and aeration assisted volatilization. These loss processes are much more dependent on residence time. Since the residence times used reflect typical to low end values ( low residence times result in less loss, so greater effluent and sludge concentration), the risk results should be similar or slightly higher than what would be seen if a waste stream with the same concentration were modeled in larger units. Dilution of these wastes with other larger waste streams not containing these chemicals ( or containing them at lower concentrations) would have a much greater impact on risk.

Attachment A. 2 provides all the WATER9 input values used for each scenario for nonaerated units and the aerated treatment train. Appendix A Data Inputs for Phase II Groundwater Modeling A 7 A. 2.3 Waste Characteristics EPA set all waste characteristics to weighted central tendency values from the SIS survey data. The median active biomass value from the SIS survey data was 0, which is a reasonable value for nonaerated units. Table A 2 presents the waste properties used.

Table A 2. Waste Properties Used in WATER9 Modeling Parameter Units Nonaerated Aerated Treatment Train Value Source Value Source Solids ppmw 141 SIS survey ( median) 200 best professional judgment Oil ppmw 0 SIS survey ( median) 1 best professional judgment Temperature C 24.52 Hartford, CT 30 best professional judgment A. 2.4 Physical Chemical Properties Some of the WATER9 chemical property default values were updated using the Superfund Chemical Data Matrix ( SCDM) ( U. S. EPA, 1997). Table A 3 presents the physicalchemical property values used and their source ( SCDM or WATER9 database).

Table A 3. Physical Chemical Properties Used in WATER9 Parameter Units Value Source Benzene 2 Ethoxyethanol 1,1,2 Trichloroethane Density g/ cm3 0.88 0.93 1.4 SCDM Molecular weight g/ mol 78 90 133 SCDM Diffusivity in water cm2/ s 1E 5 9.8E 6 1E 5 WATER9 Diffusivity in air cm2/ s 0.0895 0.082 0.067 WATER9 Vapor pressure mmHg 95 5.3 23 SCDM Henry's law constant atm m3/ m 5.55E 3 1.23E 7 9.1E 4 SCDM Vapor pressure temperature coefficient A unitless 6.9 7.9 7.2 WATER9 Vapor pressure temperature coefficient B unitless 1,200 1,800 1,500 WATER9 Vapor pressure temperature coefficient C unitless 220 230 230 WATER9 ( continued) Table A 3. ( continued) Appendix A Data Inputs for Phase II Groundwater Modeling Parameter Units Value Source Benzene 2 Ethoxyethanol 1,1,2 Trichloroethane A 8 First order biorate constant l/ g hr 1.4 1 0.74 WATER9 Zero order biorate constant mg/ g hr 19 20 3.5 WATER9 Log octanol water coefficient ( Kow) unitless 2.13  0.1 2 SCDM Solubility mg/ L 1,750 1,000,000 4,400 SCDM A. 4 Fate and Transport Inputs The groundwater DAFs are all for a no liner scenario. They vary by duration and percentile from the distribution of DAFs. The 50th percentile values were used for central tendency and the 90th percentile DAFs for high end. The duration was chosen to match the exposure duration. Table A 4 shows the DAFs used for surface impoundments, and Table A 5 shows them for landfills. Because 2 ethoxyethanol is a noncarcinogen, calculations for 2 ethoxyethanol are not affected by changes in exposure duration. Therefore, only the 9 year duration is shown for 2 ethoxyethanol.

Table A 4. IWEM Tier I DAFs for Surface Impoundments Percentile Benzene 2 Ethoxyethanol 1,1,2 Trichloroethane Duration 9 year 30 year 9 year 9 year 30 year 50th 12.5 14.9 12.3 14 16.9 90th 1.4 1.6 1.4 1.4 1.6 Table A 5. IWEM Tier I DAFs for Landfills Percentile Benzene 2 Ethoxyethanol 1,1,2 Trichloroethane Duration 9 year 30 year 9 year 9 year 30 year 50th 93.5 93.5 95.5 127 127 90th 2.2 2.2 2.2 2.5 2.5 Appendix A Data Inputs for Phase II Groundwater Modeling A 9 A. 5 Exposure Factors For central tendency exposure scenarios, exposure duration was set to 9 years. For highend exposure scenarios, exposure duration was set to 30 years. All other exposure factors are the defaults used in IWEM.

A. 6 Toxicity Attachment A. 3 summarizes how health benchmarks were set for IWEM. Table A 6 summarizes the health benchmarks for the three chemicals considered in this assessment.

Table A 6. Health Benchmarks Used in Groundwater Assessment Chemical Cancer Noncancer Ingestion CSF ( per mg/ kg d) Inhalation CSF ( per mg/ kg d) RfD ( mg/ kg d) RfC ( mg/ m3)

Benzene Central tendency 3.5E 2 5.0E 6 not used not used High end 5.5E 2 7.8E 6 not used not used 2 Ethoxyethanol NA NA 0.4 0.2 1,1,2 Trichloroethane 5.7E 2 5.6E 2 not used not used A. 7 References RTI. 2001. Risk Assessment Technical Background Document for the Paints and Coatings Hazardous Waste Listing Determination. Submitted to EPA Office of Solid Waste, Washington, DC. http:// www. epa. gov/ epaoswer/ hazwaste/ id/ paint/ ( section 1 2. pdf; section 3 4. pdf; section 5 6. pdf; and section 7 10. pdf).

U. S. EPA ( Environmental Protection Agency). 1987. 1986 National Survey of Hazardous Waste, Storage, Disposal, and Recycling Facilities Database.

U. S. EPA ( Environmental Protection Agency). 1996. Superfund Chemical Data Matrix ( SCDM). Office of Emergency and Remedial Response. Web site at http:// www. epa. gov/ oerrpage/ superfund/ resources/ scdm/ index. htm. June.

U. S. EPA ( Environmental Protection Agency). 2001. Industrial Surface Impoundments in the United States. Office of Solid Waste, Washington, DC. EPA530 R 01 005. March. Appendix A Data Inputs for Phase II Groundwater Modeling A 10 This page intentionally left blank. Attachment A 1 Description of HBN Development Methodology Used for IWEM This page intentionally left blank. RESEARCH TRIANGLE INSTITUTE MEMORANDUM Date: August 9, 2001 To: Ann Johnson, EPA From: Susan N. Wolf, Pam Birak, Jessica Lin, and Robert S. Truesdale, RTI Subject: Description of HBN development methodology used for IWEM Two Toxicity Reference Levels ( TRLs) are included in the Industrial Waste Evaluation Model ( IWEM) software: Maximum Contaminant Levels ( MCLs), which are available for some waste constituents, and Health Based Numbers ( HBNs), which are available for all waste constituents ( including waste constituent daughter products). This memorandum describes the methodology used to develop HBNs for constituents that cause cancer and constituents that produce noncancer health effects.

All constituents currently included in the IWEM software have an ingestion HBN. In IWEM, an ingestion HBN is the maximum concentration of the constituent in groundwater that is not expected to cause adverse health effects in most individuals who drink the groundwater. For organic constituents and mercury, IWEM also uses inhalation HBNs, which are the maximum concentrations of a constituent in groundwater that are not expected to cause adverse health effects in most adults who inhale the constituent while showering. To calculate HBNs, we only consider parameters that describe a constituent's health effects and an individual's ( receptor's) exposure to the constituent from drinking or showering. In contrast, the MCL includes consideration of additional factors, such as the cost of treatment, and does not consider the inhalation exposure route.

The sections below provide our methodology for calculating the cancer and noncancer HBNs for ingestion and inhalation of the contituents in IWEM. The target risk used to calculate the HBN for carcinogens is 1 × 10 6 ( unitless). The target hazard quotient used to calculate the HBN for noncarcinogens is 1.0 ( unitless). These targets are used to calculate independent HBNs for inhalation and ingestion. IWEM does not combine exposure from showering and drinking, but considers these routes of exposure separately to ensure use of the lowest, or most protective, HBN for a particular chemical.

1.0 Ingestion HBNs The IWEM ingestion HBNs are calculated using equations based on the U. S. Environmental Protection Agency's ( EPA's) Risk Assessment Guidance for Superfund: Volume 1   Human Health Evaluation Manual ( U. S. EPA, 1991). These equations and inputs Page 2 of 13 differ for cancer causing chemicals and chemicals that have adverse health effects other than cancer. The primary differences result from cancer toxicity criteria's being based on an average daily dose over a lifetime, while noncancer health benchmarks use less than lifetime estimates of exposure.

1.1 Ingestion HBNs for Constituents That Cause Cancer The equation for calculating ingestion HBNs for carcinogens uses the cancer slope factor ( CSF) exposure variables to determine the highest concentration of the carcinogen in drinking water that will not exceed the target risk. Because the CSF is based on an average day's exposure over a lifetime, the equation also requires estimates of how many days per year a person is exposed ( exposure frequency), how many years this exposure continues ( exposure duration), and the average amount of water a person drinks every day ( intake rate). Duration of exposure is critical because the CSF is based on the lifetime average daily dose. Therefore, we average the total dose received over an average person's lifetime, where the average person's lifetime is the averaging time for the exposure calculation.

where C_ INGEST_ HBN = carcinogenic risk HBN for water due to ingestion ( mg/ L) TR = target risk for carcinogens = 1 x 10 6 CSFo = oral cancer slope factor ( mg/ kg d) 1 AT = averaging time ( yr) = 70 yrs EF = exposure frequency ( d/ yr) = 350 d/ yr CRw = intake rate of water ( L/ kg/ d) ED = exposure duration ( yr) 365 = conversion factor ( d/ yr).

The sources for the exposure parameter values used to calculate the cancer HBNs are summarized in Table 1 1. To be protective of exposures to carcinogens in a residential setting, EPA focuses on exposures to individuals who may live in the same residence for a long period of time ( i. e., an exposure duration of 30 years, the 95th percentile for population mobility). Page 3 of 13 Table 1 1. Exposure Parameter Values for Carcinogens Exposure Parameter Value Units Source Drinking Water Intake Rate 25.2 mL/ kg/ d The value is a time weighted average of mean drinking water intake rates for adults aged 0 to 29 years.

Table 3 7 of the Exposure Factors Handbook ( U. S. EPA, 1997a)

Exposure Frequency 350 d/ yr The exposure frequency is the number of days per year that an individual is exposed. A value of 350 days per year considers that an individual is away from home for 2 weeks per year.

Risk Assessment Guidance for Superfund: Volume 1   Human Health Evaluation Manual ( U. S. EPA, 1991)

Exposure Duration 30 yr The exposure duration is the number of years that an individual is exposed. Thirty years is the 95th percentile value for population mobility ( exposure duration).

Table 15 176 of the Exposure Factors Handbook ( U. S. EPA, 1997b)

Averaging Time 70 yr Risk Assessment Guidance for Superfund: Volume 1   Human Health Evaluation Manual ( U. S. EPA, 1991)

1.2 Ingestion HBNs for Constituents that Cause Noncancer Health Effects To develop ingestion HBNs for constituents that cause health effects other than cancer, we used an equation that determines the maximum concentration that will not exceed the target hazard quotient. The equation uses the reference dose, which is the maximum average daily dose that will not cause adverse health effects, and requires estimates of exposure frequency and water intake rate. Page 4 of 13 where NC_ INGEST_ HBN = noncarcinogenic risk HBN for water ( mg/ L) THI = target hazard index for noncarcinogens = 1 RfD = reference dose ( mg/ kg d) EF = exposure frequency ( d/ yr) = 350 d/ yr CRw = intake rate of water for a child aged 1 to 6 yrs ( L/ kg/ d) 365 = conversion factor ( d/ yr).

The sources for the exposure parameter values used to calculate the noncancer HBN are summarized in Table 1 2. Because toxicity criteria for noncarcinogens are based on less thanlifetime exposures, and to be protective of toxic effects to children, the equation uses a drinking water intake rate that is appropriate for children under 6 years old.

Table 1 2. Exposure Parameter Values for Noncancer Health Effects Exposure Parameter Value Units Source Drinking Water Intake Rate 42.6 mL/ kg/ d The value is a time weighted average of mean drinking water intake rates for children aged 0 to 6 years.

Table 3 7 of the Exposure Factors Handbook ( U. S. EPA, 1997a)

Exposure Frequency 350 d/ yr The exposure frequency is the number of days per year that an individual is exposed. A value of 350 days per year considers that an individual is away from home for 2 weeks per year.

Risk Assessment Guidance for Superfund: Volume 1   Human Health Evaluation Manual ( U. S. EPA, 1991)

2.0 Inhalation HBN Methodology In IWEM, the inhalation HBN is the maximum concentration of a constituent in groundwater that is not expected to cause adverse health effects in most adults who inhale the constituent as a result of activities associated with showering ( we assume that children take baths; consequently, we do not evaluate children's shower related exposure). The inhalation HBN is the groundwater concentration that results in a target risk of 1 × 10 6 for carcinogens or a Page 5 of 13 target hazard quotient of 1 for noncarcinogens. We only calculated inhalation HBNs for constituents that ( 1) volatilize ( e. g., mercury and organic constituents) and ( 2) have an inhalation health benchmark available ( e. g., reference concentrations [ RfC], inhalation unit risk factors [ URF], and/ or inhalation cancer slope factors [ CSFi]). Inhalation HBNs were not calculated for airborne metal particles because we do not expect these to be produced by a shower.

We developed the inhalation HBNs in two basic steps. First, Section 2.1 describes how we used a shower model to calculate the average concentration of a waste constituent in air that an adult will be exposed to both during showering and during time spent in the shower stall and/ or bathroom after showering. ( The HBNs do not reflect inhalation exposure to groundwater that results from other household uses of water.) Because the relationship between groundwater concentration and risk ( or hazard quotient) is linear, we used a single unit groundwater concentration ( e. g., 1 mg/ L) that was within the solubility limits of the constituent so that the model would calculate a unit average shower air concentration. To reflect average daily dose, the model adjusted this unit shower air concentration and outputs a unit average daily indoor air concentration for the second step of the analysis.

Second, we used this unit average indoor air concentration in air to calculate the HBN. The HBN equations first calculate the risk or hazard quotient associated with the unit air concentrations from the shower model, and then use ratios to determine the groundwater concentration ( or HBN) associated with the target risk level or target hazard quotient. Section 2.2 describes the application of the HBN equations for cancer causing chemicals and for chemicals with non cancer health effects.

2.1 Calculation of Exposure Concentrations from Showering Individuals may be exposed to waste constituents through inhalation of vapor phase emissions from groundwater. Such exposure may occur during the time spent in the shower while showering, in the shower stall after showering, and in the bathroom after showering. To evaluate these exposures, EPA used a shower model to calculate the average constituent concentration in the shower stall and bathroom air. This section describes this model and assumptions ( Section 2.1.1) along with uncertainties and limitations associated with its use ( Section 2.1.2).

A primary assumption of this evaluation is that the gas phase concentration of a constituent results solely from showering activity. Previous versions of the shower model included emissions due to other household uses of water and risks due to inhalation for time spent in the remainder of the house. However, the risk from inhalation exposures in the remainder of the house has been shown to be several orders of magnitude lower than the risk from inhalation exposures in the bathroom and during showering ( EPA, 1997d). Given the low risk due to exposure from the remainder of the house and the difficulty in collecting the input data needed to estimate household chemical concentrations from other sources, the current version of the shower model has been simplified to focus on the greatest sources of exposure and risk due to use of contaminated water. Page 6 of 13 2.1.1 Shower Model The shower model estimates the change in the shower constituent air concentrations over time as a function of the mass of constituent transferred from the shower water to shower vapors. After calculating the predicted vapor phase constituent concentration in the shower stall and bathroom during showering, the model calculates an average daily indoor air concentration using volumetric air exchange rates between the shower stall, bathroom, and house. The shower model is based on differential equations presented in McKone ( 1987) and Little ( 1992). Memo Attachment A provides details on these equations and explains how we implemented them in the model. Tables A 1 to A 11 ( in Memo Attachment A) present the equations, and Table A 12 ( in Memo Attachment A) provides the model parameters for exposure ( e. g., exposure time, shower properties).

The model's calculations of mass transfer between the liquid and vapor phases of the constituent in the shower, and subsequent air transfer between the shower stall and bathroom depend on both physical parameters ( shower properties) and chemical specific properties. With respect to chemical specific properties, a constituent's ability to transfer mass from the liquid phase to gas phase is characterized by its diffusivity, or how well it mixes with other gases. Diffusion coefficients in air and water quantify diffusivity for each constituent, which depends on the constituent's density and molecular weight. Transfer from the shower water to air is controlled by the air pressure in the shower stall. We used Henry's law to quantify the amount of constituent dissolved in the shower water ( equation in Table A 3 of Memo Attachment A). Henry's law states that the amount of a gas dissolved in solution is directly proportional to the pressure of the gas above the solution. Once a constituent's diffusion coefficients in air and water and its Henry's law constant coefficient were known, an overall mass transfer coefficient was calculated to quantify the constituent's ability to volatilize from the shower water into the air ( equation in Table A 5 of Memo Attachment A).

The physical properties of the shower also affect constituent air concentrations. There are macro level parameters, such as the volume of the shower stall, the water flow rate, and the height of the nozzle, which limit the length of time the constituent is in the shower stall and the amount of it that may accumulate in the shower air. These macro level physical parameters were set to standard values, based on available literature ( see Table 2 1). These shower parameters provide a cap on the maximum possible constituent concentration that may accumulate in the shower stall, and they are required to calculate equilibrium constituent concentrations between the water and air during shower time ( equations in Table A 6 of Memo Attachment A).

On a smaller scale, the fraction of constituent emitted by a water droplet into the shower air depends upon the level of gas phase saturation in the shower stall and a dimensionless mass transfer coefficient ( equation in Table A 7 of Memo Attachment A). Calculation of the dimensionless mass transfer coefficient uses micro level droplet properties, such as droplet diameter and velocity, and some macro level shower properties discussed above to quantify the length of time a constituent is in contact with the surrounding air and the amount that may volatilize ( surface area of the droplet) ( equation in Table A 4 of Memo Attachment A). The droplet's diameter ( 0.098 cm) and velocity ( 400 cm/ s) were set to constant values that correlated well with existing data ( Table 2 1). Page 7 of 13 Table 2 1. Shower Model Input Parameters Input Parameter Description Value Units Reference Comment ShowerStallTime Time in shower stall after showering 5 min U. S. EPA, 1997c Table 15 23. 50th percentile overall T_ bathroom Time spent in bathroom, not in shower 5 min U. S. EPA, 1997c Table 15 32. 50th percentile overall ShowerTime Shower time, 50th percentile 15 min U. S. EPA, 1997c Table 15 21. 50th percentile overall Vb Volume of the bathroom 10 m3 McKone, T., 1987 Vs Volume of shower 2 m3 McKone, T., 1987 NozHeight Height of shower head 1.8 m Little, J., 1992 Selected based on the maximum height reported in Table 1, a summary of five studies.

Qsb Volumetric exchange rate between the shower and the bathroom 100 L/ min RTI derived value Estimated from the volume and flow rate in McKone ( 1987) such that the exchange rate equals the volume divided by the residence time ( e. g.,

2000L/ 20 min).

ShowerRate Rate of water flow from shower head 10 L/ min RTI derived value Value obtained by averaging the flow rates reported in five studies in Table 1 of Little ( 1992) ( QL) =

10.08 L/ min.

DropVel Terminal velocity of water drop 400 cm/ s RTI derived value Selected value by correlating to existing data.

DropDiam Diameter of shower water drop 0.098 cm RTI derived value Estimated as a function of terminal velocity<= 600cm/ sec ( Coburn, 1996).

Qbh Volumetric exchange rate between the bathroom and the house 300 L/ min RTI derived value Estimated from the volume and flow rate in McKone ( 1987) such that the exchange rate equals the volume divided by the residence time ( e. g.,

10,000L/ 30 min).

Cin Constituent concentration in incoming water 0.001 mg/ L NA Unit concentration selected. Page 8 of 13 After calculating the fraction of constituent that can be emitted from a droplet, the shower model calculates the potential amount of constituent mass that may be emitted into the air during 0.2 minute time steps for the duration of the showering time. The mass emitted during a time step is limited by the fraction that can be emitted and the existing gas phase constituent concentration in the shower stall at the beginning of the time step. We calculate this incremental mass using the physical parameters of the shower in conjunction with constituent specific properties to estimate how much constituent may accumulate in the shower air ( equation in Table A 6 of Memo Attachment A).

Because of air flow between the shower stall and bathroom, the actual gas phase constituent concentration in the shower is less than the potential amount calculated above. The volumetric exchange rates between the shower stall and bathroom and the bathroom and rest of the house were assigned constant values derived from McKone ( 1987) ( Table 2 1). These two parameters quantify the dilution of constituent concentration in the shower air. The shower model uses these two loss components to calculate the actual constituent concentration in the shower stall and in the bathroom at the end of each time step ( equations in Tables A 9 and A 10 of Memo Attachment A).

To calculate average daily indoor air concentrations, values for exposure time were taken from the Exposure Factors Handbook ( EPA, 1997a). We selected the 50th percentile for adults' time spent taking a shower, time spent in the shower stall after showering, and time spent in the bathroom after showering ( Table 2 1). The shower model calculates constituent concentrations in the shower stall and bathroom for each time step until the end of the time spent in the shower and bathroom, and then averages constituent concentrations for the two compartments. The model then calculates the daily indoor constituent concentration by averaging these concentrations over the length of an entire day ( equation in Table A 11 of Memo Attachment A), assuming that there is no additional inhalation exposure to the constituent during the day ( i. e., that the gas phase constituent concentration in the house is negligible).

2.1.2 Shower Model Uncertainties and Limitations A primary limitation of the shower model is that the gas phase concentration of a constituent in the house results only from shower related activities. The model does not include other household uses of water ( e. g., toilet use) in calculating average indoor concentrations. However, the risk of inhalation exposure from other water use activities has been demonstrated to be several magnitudes lower than the exposure risk from showering ( EPA, 1997d). In addition, there is also large uncertainty in estimating other household activity chemical concentrations. To quantify the inhalation exposure risk for the entire house, the model would require an estimate of the air exchange rate between the house and outdoor air, exposure time in the house, and the amount of nonshower water usage. Given the uncertainties in these input parameters and the low risk due to exposure from the remainder of the house, the shower model focuses only on the greatest source of exposure and risk due to use of contaminated water.

The input parameter values are another source of uncertainty for the shower model. In selecting values for the shower properties ( shower and bathroom volume, nozzle height, and Page 9 of 13 flow rate), we used in most cases mid range values that were reported in the literature. Though setting the shower parameters to constants does not capture possible variability in these variables, the results using these fixed values compare favorably to experimental data for numerous organic compounds of varying volatility ( Coburn, 1996). The droplet properties ( diameter and velocity) are also constants, but their values were selected based on correlation to existing data, resulting in less uncertainty. The largest uncertainty is likely in the volumetric exchange rates used between the shower and bathroom and the bathroom and the rest of house. These values, 300 L/ min for the exchange rate between the bathroom and the house, and 100 L/ min for the exchange rate between the shower and the bathroom, were derived from McKone ( 1987). The range of values reported in a five study summary ( Little, 1992), however, was 35 to 460 L/ min for exchange between the shower and the bathroom and 38 to 480 L/ min for exchange between the bathroom and the rest of the house, making these the most uncertain variables among the shower model inputs.

2.2 Calculating Inhalation HBNs To calculate HBNs, we selected a unit groundwater concentration ( usually 1 mg/ L) within the solubility limits of each constituent and ran the shower model using that concentration to calculate a unit average daily indoor air concentration. We used this unit air concentration to calculate a corresponding unit risk ( for cancer causing chemicals) or unit hazard quotient ( for constituents with noncancer health effects). Because there is a linear relationship between groundwater concentration and risk, we could use simple ratios to adjust the unit groundwater concentrations to the groundwater concentration corresponding to the target risk or target hazard quotient ( i. e., the inhalation HBN). Section 2.2.1 describes this process for carcinogens while Section 2.2.2 discusses the approach we used for noncarcinogens. As a final step, we checked every inhalation HBN to ensure that it did not exceed the constituent's solubility, as described in Section 2.2.3.

2.2.1 Inhalation HBNs for Carcinogens To calculate the inhalation HBN for carcinogens, we first calculate the average daily dose ( ADD) from inhalation due to exposure to contaminated groundwater during showering. The ADD is calculated from the unit air concentration output by the shower model, as follows:

where ADD = average daily dose ( mg/ kg d) at the unit groundwater concentration Cair_ indoor = average air concentration over a day ( mg/ m3) ( calculated from the unit groundwater concentration using the shower model) IR = inhalation rate ( m3/ d) Page 10 of 13 BW = body weight ( kg).

We then calculated the risk at the modeled unit groundwater concentration from the ADD, as shown below:

where Risk_ modeled = risk resulting from groundwater concentration modeled ED = exposure duration ( yr) = 30 yr EF = exposure frequency ( d/ yr) = 350 d/ yr AT = averaging time ( yr) = 70 yr CSFi = inhalation cancer slope factor ( mg/ kg d) 1 ADD = average daily dose ( mg/ kg d) at the unit groundwater concentration 365 = conversion factor ( d/ yr).

We then derived the target groundwater concentration ( i. e., the inhalation HBN) by adjusting the modeled unit groundwater concentration using the simple ratio of target risk to the modeled risk:

where HBN = concentration in groundwater resulting in target risk (: g/ L) C_ GW_ modeled = unit concentration in groundwater used in shower model (: g/ L) Risk_ T = target risk for carcinogens = 1 x 10 6 Risk_ modeled = risk resulting from groundwater concentration modeled.

This equation assumes that the relationship between groundwater concentration and risk is linear, which we confirmed by running the shower model using the target groundwater concentration for several constituents and comparing the results to the target risk level.

The inhalation HBNs for cancer causing chemicals were based on adult exposure parameters. The sources for the exposure parameter values used in the equations above are summarized in Table 2 2. Page 11 of 13 Table 2 2. Exposure Parameter Values Exposure Parameter Value Units Source Inhalation Rate 13.25 m3/ d The value corresponds to the mean inhalation rates for adults aged 19 to 65+. The value was calculated by averaging the daily mean inhalation rates for females ( 11.3 m3/ d) and males ( 15.2 m3/ d).

Table 5 23 of the Exposure Factors Handbook ( U. S. EPA, 1997a)

Body Weight 71.8 kg The value corresponds to the mean body weight of 18 to 75 year old men and women.

Tables 7 2 and 7 11 of the Exposure Factors Handbook ( U. S. EPA, 1997a)

Exposure Frequency 350 d/ yr The exposure frequency is the number of days per year that an individual is exposed. A value of 350 days per year considers that an individual is away from home for 2 weeks per year.

Risk Assessment Guidance for Superfund: Volume 1   Human Health Evaluation Manual ( U. S. EPA, 1991)

Exposure Duration 30 yr The exposure duration is the number of years that an individual is exposed. Thirty years is the 95th percentile value for population mobility ( exposure duration).

Table 15 176 of the Exposure Factors Handbook ( U. S. EPA, 1997b)

Averaging Time 70 yr Risk Assessment Guidance for Superfund: Volume 1   Human Health Evaluation Manual ( U. S. EPA, 1991)

2.2.1 Inhalation HBNs for Noncarcinogens Calculating inhalation HBNs for noncarcinogens is simpler than calculating them for carcinogens because the toxicity criterion ( RfC) is expressed as a concentration in air. The HBN Page 12 of 13 is calculated by first determining the hazard quotient resulting from the unit air concentration output by the shower model:

where HQ_ modeled = hazard quotient resulting from the groundwater concentration modeled Cair_ indoor = average air concentration over a day ( mg/ m3) ( calculated from the unit groundwater concentration using the shower model) RfC = reference concentration ( mg/ m3).

We then derived the target groundwater concentration ( i. e., the inhalation HBN) by adjusting the modeled unit groundwater concentration using the simple ratio of target hazard quotient to the modeled hazard quotient:

where HBN = concentration in groundwater resulting in target hazard quotient (: g/ L) C_ GW_ modeled = unit concentration in groundwater used in shower model (: g/ L) THQ = target hazard quotient for noncarcinogens = 1 HQ_ modeled = hazard quotient resulting from groundwater concentration modeled.

2.2.3 Solubility Check After calculation, we checked each HBN to ensure that it did not exceed the solubility of the chemical in water ( see Memo Attachment B for the aqueous solubilities used for this check). This check was necessary because above the solubility limit, the water is saturated with the chemical, and any additional chemical is present in a free, separate phase ( pure liquid or solid). Above saturation, Henry's law ( a basic principle of the shower volatilization model) does not apply, and the emission flux from water to air reaches a plateau. In other words, volatile emissions will not increase above this level no matter how much chemical is added to the water ( U. S. EPA, 1996). Because of this fact, a calculated HBN above solubility indicates that a constituent does not pose a significant inhalation risk, and IWEM does not include an inhalation HBN for that constituent. In these cases, IWEM will evaluate the constituent based on its ingestion risk alone. Page 13 of 13 REFERENCES:

Coburn, J. 1996. Memo to Dana Greenwood on Emission Flux Equations for Showering, July 1.

Little, John C. 1992. Applying the two resistance theory to contaminant volatilization in showers. Environmental Science and Technology 26: 1341 1349.

McKone, Thomas E. 1987. Human exposure to volatile organic compounds in household tap water: The indoor inhalation pathway. Environmental Science and Technology 21: 1194 1201.

U. S. Environmental Protection Agency ( EPA). 1991. Risk Assessment Guidance for Superfund: Volume 1  Human Health Evaluation Manual ( Part B, Development of Risk Based Preliminary Goals). EPA/ 540/ R 92/ 003. Interim Draft. Office of Emergency and Remedial Response, U. S. EPA, Washington, DC.

U. S. Environmental Protection Agency ( EPA). 1996. Soil Screening Guidance: Technical Background Document. EPA/ 540/ R95/ 128. Office of Solid Waste and Emergency Response. May.

U. S. Environmental Protection Agency ( EPA). 1997a. Exposure Factors Handbook, Volume I, General Factors. EPA/ 600/ P 95/ 002Fa. Office of Research and Development, Washington, DC.

U. S. Environmental Protection Agency ( EPA). 1997b. Exposure Factors Handbook, Volume II, Food Ingestion Factors. EPA/ 600/ P 95/ 002Fb. Office of Research and Development, Washington, DC.

U. S. Environmental Protection Agency ( EPA). 1997c. Exposure Factors Handbook, Volume III, Activity Factors. EPA/ 600/ P 95/ 002Fc. Office of Research and Development, Washington, DC.

U. S. Environmental Protection Agency ( EPA). 1997d. Supplemental Background Document; Nongroundwater Pathway Risk Assessment; Petroleum Process Waste Listing Determination. Office of Solid Waste, Research Triangle Park, NC. This page intentionally left blank. Memo Attachment A Shower Algorithms This page intentionally left blank. Memo Attachment A Page 1 of 10 BSResTime ShowerTime ShowerStallTime T_ bathroom = + +

ShowerResTime ShowerStallTime ShowerTime = + Table A 1. Total time spent in shower and bathroom Shower Name Description Value BSResTime Total time spent in shower and bathroom ( min) Calculated above ShowerTime Duration of shower ( min) Provided in Table A 12 ShowerStallTime Time in shower stall after showering ( min) Provided in Table A 12 T_ bathroom Time spent in bathroom, not in shower ( min) Provided in Table A 12 This equation calculates the total time that a receptor is exposed to vapors.

Table A 2. Total time spent in shower stall Shower Name Description Value ShowerResTime Total time spent in shower stall ( min) Calculated above ShowerStallTime Time in shower stall after showering ( min) Provided in Table A 12 ShowerTime Duration of shower ( min) Provided in Table A 12 This equation calculates the total time that a receptor is exposed to vapors in the shower stall. Memo Attachment A Page 2 of 10 Hprime HLCcoef HLC HLCcoef R Temp = × = × 1 Table A 3. Dimensionless Henry's law constant Shower Name Description Value Hprime Dimensionless Henry's law constant ( dimensionless) Calculated above HLCcoef Coefficient to Henry's law constant ( dimensionless) Calculated above HLC Henry's law constant ( atm m3/ mol) Chemical specific R Ideal Gas constant ( atm m3/ K Mol) 0.00008206 Temp Temperature ( K) 298 This equation calculates the dimensionless form of Henry's law constant. Memo Attachment A Page 3 of 10 N = Kol AVRatio DropResTime DropResTime × × =

= × AVRatio DropDiam NozHeight DropVel 6 100 Table A 4. Dimensionless overall mass transfer coefficient Shower Name Description Value N Dimensionless overall mass transfer coefficient ( dimensionless) Calculated above AVRatio Area to volume ratio for a sphere ( cm2/ cm3) Calculated above Kol Overall mass transfer coefficient ( cm/ s) Calculated in Table A 5 DropResTime Residence time for falling drops ( s) Calculated above DropDiam Drop diameter ( cm) Provided in Table A 12 NozHeight Nozzle height ( m) Provided in Table A 12 DropVel Drop terminal velocity ( cm/ s) Provided in Table A 12 100 Conversion factor ( cm/ m) Conversion factor This equation calculates the dimensionless overall mass transfer coefficient. The above equation is based on Little ( 1992a), which provides the equation as N = Kol × A/ Q1 where A is surface area and Q1 is flow in volume per time. Memo Attachment A Page 4 of 10 Kol D D Hprime w a = × + ×

  25 1 2 3 2 3 1 . / / Table A 5. Overall mass transfer coefficient Shower Name Description Value Kol Overall mass transfer coefficient ( cm/ s) Calculated above beta Proportionality constant ( cm s^ 1/ 3) 216 Dw Diffusion coefficient in water ( cm2/ s) Chemical specific Da Diffusion coefficient in air ( cm2/ s) Chemical specific Hprime Dimensionless Henry's law constant ( dimensionless) Calculated in Table A 3 This equation calculates the overall mass transfer coefficient. The above equation corresponds to Equation 17 in McKone ( 1987) and was modified to use the dimensionless Henry's law constant. The value for beta was derived based on data for benzene and verified for chemicals of varying volatility ( Coburn, 1996). Memo Attachment A Page 5 of 10 Es = Emax Es Et =

( ) Et Cin ShowerRate ts fem y y Vs eq s t = × × × =   × × Emax 1000 , Table A 6. Contaminant mass emitted in the shower for a given time step Shower For Et > Emax,

For Et # Emax,

Where,

Name Description Value Es Contaminant mass emitted in the shower for a given time step ( mg) Calculated above Emax Maximum possible mass of constituent emitted from shower during time step ( mg) Calculated above Et Potential mass of constituent emitted from shower during time step ( mg) Calculated above yeq Gas phase constituent concentration in equilibrium between water and air ( mg/ L) Hprime x Cin ys, t Gas phase constituent concentration in the shower at the beginning of time step ( mg/ L) Calculated from last time step Vs Volume of shower ( m3) Provided in Table A 12 Cin Liquid phase constituent concentration in the incoming water ( mg/ L) Provided in Table A 12 ShowerRate Rate of flow from showerhead ( L/ min) Provided in Table A 12 ts Time step ( min) 0.2 fem Fraction of constituent emitted from a droplet ( dimensionless) Calculated in Table A 7 Hprime Dimensionless Henry's law constant ( dimensionless) Calculated in Table A 3 1000 Conversion factor ( L/ m3) Conversion factor The above equations are used to determine the mass of contaminant emitted for a given time step. The equilibrium concentration in air ( y_ eq) is calculated from Equation 1 in Little ( 1992a). If the mass emitted based on the mass transfer coefficient ( Et) is greater than the amount emitted to reach equilibrium ( Emax), the mass is set to the amount that results in the air concentration at equilibrium. Memo Attachment A Page 6 of 10 ( ) ( ) fem Fsat e N =   ×

1 1 Fsat y y s t eq = , Table A 7. Fraction of constituent emitted from a droplet Shower Name Description Value fem Fraction of constituent emitted from a droplet ( dimensionless) Calculated above Fsat Fraction of gas phase saturation ( dimensionless) Calculated in Table A 8 N Dimensionless overall mass transfer coefficient ( dimensionless) Calculated in Table A 4 This equation is used to calculate the fraction of a given chemical emitted from a droplet of water in the shower. The equation is based on Equation 5 in Little ( 1992a). The above equation is obtained by rearranging the equation in Little given that ys_ max/ m = Cin and f_ sat = ys/ ys_ max = ys/( m × Cin).

Table A 8. Fraction of gas phase saturation in shower Shower Name Description Value Fsat Fraction of gas phase saturation in shower ( dimensionless) Calculated above yeq Gas phase contaminant concentration in equilibrium between water and air ( mg/ L) Hprime x Cin ys, t Current gas phase contaminant concentration in air ( mg/ L) Calculated in Table A 9 ( as ys, t+ ts for previous time step)

Hprime Dimensionless Henry's law constant ( dimensionless) Calculated in Table A 3 Cin Constituent concentration in incoming water ( mg/ L) Provided in Table A 12 This equation is used to calculate the fraction of gas phase saturation in shower for each time step. The equilibrium concentration in air ( y_ eq) is calculated from Equation 1 in Little ( 1992a). Memo Attachment A Page 7 of 10 ( ) ( ) [ ] y y E Q y y ts V s t ts s t s sb st bt s , , , , + = +   ×   × × 1000 Table A 9. Gas phase constituent concentration in the shower at end of time step Shower Name Description Value ys, t+ ts Gas phase constituent concentration in the shower at end of time step ( mg/ L) Calculated above ys, t Gas phase constituent concentration in the shower at the beginning of time step ( mg/ L) Calculated from last time step yb, t Gas phase constituent concentration in the bathroom at the beginning of time step ( mg/ L) Calculated from last time step Es Mass emitted in the shower for a given time step ( mg) Calculated in Table A 6 Qsb Volumetric exchange rate between the shower and the bathroom ( L/ min) Provided in Table A 12 Vs Volume of shower ( m3) Provided in Table A 12 ts Time step ( min) 0.2 1000 Conversion factor ( L/ m3) Conversion factor This equation is used to calculate the gas phase constituent concentration in the shower at end of time step. The equation is derived from Equation 9 in Little ( 1992a). Es is set to 0 when the shower is turned off ( i. e., at the end of showering) to estimate the reduction in shower stall air concentrations after emissions cease. Memo Attachment A Page 8 of 10 ( ) ( ) ( ) [ ] y y Q y y Q y y V ts b t ts b t sb s t ts b t bh b t h t b , , , , , , + + = + ×     ×

× × 1000 Table A 10. Gas phase constituent concentration in the bathroom at end of time step Shower Name Description Value yb, t+ ts Gas phase constituent concentration in the bathroom at end of time step ( mg/ L) Calculated above yb, t Gas phase constituent concentration in the bathroom at the beginning of time step ( mg/ L) Calculated from last time step ys, t+ ts Gas phase constituent concentration in the shower at the end of time step ( mg/ L) Calculated in Table A 9 yh, t Gas phase constituent concentration in the house at the beginning of time step ( mg/ L) Assumed deminimus, zero Qsb Volumetric exchange rate between the shower and the bathroom ( L/ min) Provided in Table A 12 Qbh Volumetric exchange rate between the bathroom and the house ( L/ min) Provided in Table A 12 Vb Volume of bathroom ( m3) Provided in Table A 12 ts Time step ( min) 0.2 1000 Conversion factor ( L/ m3) Conversion factor This equation is used to calculate the gas phase constituent concentration in the bathroom at end of time step. The equation is derived from Equation 10 in Little ( 1992a). Memo Attachment A Page 9 of 10 ( )( )

( ) [ ]

( ) [ ] C C ShowerResTime C T bathroom C y y n C y y air indoor air shower air bathroom air shower s t ts s t s air bathroom b t ts b t _ _ _

_ ,

_ , , _

, /

/ = × + × = + × = + × +

+

  1440 1000 1000 nb 2 2 Table A 11. Average daily concentration in indoor air Shower Name Description Value Cair_ indoor Average daily concentration in indoor air ( mg/ m3) Calculated above Cair_ shower Average concentration in shower ( mg/ m3) Calculated above Cair_ bathroom Average concentration in bathroom ( mg/ m3) Calculated above ShowerResTime Total time spent in shower stall ( min) Calculated in Table A 2 T_ bathroom Time spent in bathroom, not in shower ( min) Provided in Table A 12 ys, t Gas phase constituent concentration in the shower at the beginning of time step ( mg/ L) Calculated from last time step ys, t+ ts Gas phase constituent concentration in the shower at the end of time step ( mg/ L) Calculated in Table A 9 yb, t Gas phase constituent concentration in the bathroom at the beginning of time step ( mg/ L) Calculated from last time step yb, t+ ts Gas phase constituent concentration in the bathroom at the end of time step ( mg/ L) Calculated in Table A 10 ns Number of time steps corresponding to time spent in the shower ( dimensionless) Summed in model code nb Number of time steps corresponding to time spent in the bathroom ( dimensionless) Summed in model code 1440 Minutes per day ( min)

1000 Conversion factor ( L/ m3) Conversion factor The above equations are used to calculate the time weighted average daily indoor air concentration to which a receptor is exposed. The equation assumes that receptors are only exposed to contaminants in the shower and bathroom. Memo Attachment A Page 10 of 10 Table A 12. Model parameters for exposure Name Description Value Reference Comments Bathroom properties Vb Volume of the bathroom ( m^ 3) 10 McKone, T., 1987 Exchange rate Qbh Volumetric exchange rate between the bathroom and the house ( L/ min) 300 RTI derived value Estimated from the volume and flow rate in McKone ( 1987) such that the exchange rate equals the volume divided by the residence time ( i. e., 10,000L/ 30 min).

Qsb Volumetric exchange rate between the shower and the bathroom ( L/ min) 100 RTI derived value Estimated from the volume and flow rate in McKone ( 1987) such that the exchange rate equals the volume divided by the residence time ( i. e., 2000L/ 20 min).

Exposure time ShowerStallTime Time in shower stall after showering ( min) 0 NA Only assessing exposure from time spent showering.

ShowerTime Shower time, 50th percentile ( min) 15 U. S. EPA, 1997 Table 15 21, 50th percentile overall.

T_ bathroom Time spent in bathroom, not in shower ( min) 0 NA Only assessing exposure from time spent showering.

Shower properties DropDiam Diameter of shower water drop ( cm) 0.098 RTI derived value Estimated as a function of terminal velocity ( Coburn, 1996).

DropVel Terminal velocity of water drop ( cm/ s) 400 RTI derived value Estimated by correlating to existing data ( Coburn, 1996).

NozHeight Height of shower head ( cm) 180 Little, J., 1992a Selected based on values presented in Little.

ShowerRate Rate of water flow from shower head ( L/ min) 5.5 RTI derived value Calculated based on droplet diameter and nozzle velocity.

Vs Volume of shower ( m^ 3) 2 McKone, T., 1987 Groundwater Cin Constituent concentration in incoming water ( mg/ L) 0.001 NA Unit concentration selected. Memo Attachment B Contaminant Specific Chemical and Physical Properties This page intentionally left blank. Memo Attachment B Page 1 of 9 Memo Attachment B Contaminant Specific Chemical and Physical Properties To calculate inhalation HBNs, the shower model requires input of several chemicalspecific properties, including Henry's law constant ( HLC), solubility ( Sol), and diffusion coefficients in air ( Da) and water ( Dw). This attachment describes the data sources and methodologies used to collect and develop these properties. Table B 1 ( at the end of this attachment) lists by contaminant the chemical specific properties used to calculate inhalation HBNs, along with the data source for each value.

B. 1 Data Collection Procedure To select data values available from multiple sources, we created a hierarchy of references based on the reliability and availability of data in such sources. Our first choice for data collection and calculations was EPA reports and software. When we could not find data or equations from EPA publications, we consulted highly recognized sources, including chemical information databases on the Internet. These on line sources are compilations of data that provide the primary references for data values. The specific hierarchy varied among properties as described in subsequent sections.

For dioxins, the preferred data source in all cases was the Exposure and Human Health Reassessment of 2,3,7,8 Tetrachlorodibenzo p Dioxin ( TCDD) and Related Compounds, Part 1, Vol. 3 ( Dioxin Reassessment) ( U. S. EPA, 2000). We used the Mercury Study Report to Congress ( U. S. EPA, 1997a) as the preferred source for mercury properties. If values were unavailable from these sources, we followed the same reference hierarchy that was used for other contaminants.

All data entry for chemical and physical properties was checked by comparing each entry against the original online or hardcopy reference. All property calculation programs were checked using hand calculations to ensure that they were functioning correctly.

B. 2 Solubility ( Sol)

For solubility ( Sol) values, we looked for data by searching the following sources in the following order:

1. Superfund Chemical Data Matrix ( SCDM) ( U. S. EPA, 1997b); 2. CHEMFATE Chemical Search ( SRC, 1999); 3. Hazardous Substances Data Bank ( HSDB) ( U. S. NLM, 2001); 4. ChemFinder ( CambridgeSoft Corporation, 2001). Memo Attachment B Page 2 of 9 HLC P Sol vp = For mercury, we obtained a solubility for elemental mercury from The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals ( Budavari, 1996).

B. 3 Henry's Law Constant ( HLC)

Collection of Henry's law constant ( HLC) data proceeded by searching sources in the following order:

1. SCDM; 2. CHEMFATE; 3. HSDB.

When we could not find data from these sources, we calculated HLC using equation 15 8 from Lyman, Reehl, and Rosenblatt ( 1990):

where HLC = Henry's law constant ( atm m3/ mole) Pvp = vapor pressure ( atm) Sol = solubility ( mol/ m3).

B. 4 Diffusion Coefficient in Water ( Dw)

For all chemicals, we calculated the diffusion coefficient in water ( Dw) by hand because few empirical data are available. The preferred calculation was equation 17 6 from the WATER9 model ( U. S. EPA, 2001):

D T MW w = +

0 0001518 27316 29816 0 6 . . . .

  where Dw = diffusion coefficient in water ( cm2/ s) T = temperature ( degrees C) MW = molecular weight ( g/ g mol) D = density ( g/ cc).

When we did not know chemical density, we used equation 3.16 from Process Coefficients and Models for Simulating Toxic Organics and Heavy Metals in Surface ( Process Coefficients) ( U. S. EPA, 1987), which only requires molecular weight: Memo Attachment B Page 3 of 9 Dw MW = ×   0 00022 2 3 . /

Da MW = ×   19 2 3 . / ( ) D T MW MW MW a = + +

            +                 0 0029 27316 0 034 1 1 0 000015 25 18 1 5 2 0 333 2 . ( . ) . .

. . .

.

  where Dw = diffusion coefficient in water ( cm2/ s) MW = molecular weight ( g/ mol).

B. 5 Diffusion Coefficient in Air ( Da)

All diffusion coefficients in air ( Da) were calculated values because few empirical data are available. Similar to Dw, we first consulted WATER9 and then used U. S. EPA ( 1987). Equation 17 5 in WATER9 calculates diffusivity in air as follows:

where Da = diffusion coefficient in air ( cm2/ s) T = temperature ( degrees C) MW = molecular weight ( g/ g mol) D = density ( g/ cc).

When density was not available, we used equation 3.17 from Process Coefficients ( U. S. EPA, 1987):

where Da = diffusion coefficient in air ( cm2/ s) MW = molecular weight ( g/ mol).

For dioxins and dibenzofurans, we used an equation from the Dioxin Reassessment ( U. S. EPA, 2000) to estimate diffusion coefficients from diphenyl's diffusivity:

D D MW MW a b b a =             0 5 .

where Da = diffusion coefficient of constituent in air ( cm2/ s) Db = diffusion coefficient of diphenyl at 25 degrees C ( 0.068 cm2/ s) MWa = molecular weight of constituent ( g/ mole) MWb = molecular weight of diphenyl ( 154 g/ mole). Memo Attachment B Page 4 of 9 Table B 1. Contaminant specific Chemical and Physical Properties Contaminant CASRN Da ( cm2/ s) Dw ( cm2/ s) HLC ( atm m3/ mol) Sol ( mg/ L) Acetaldehyde ( ethanal) 75 07 0 1.28E 01 e 1.35E 05 e 7.89e 05 a 1.00e+ 06 a Acetone ( 2 propanone) 67 64 1 1.06E 01 e 1.15E 05 e 3.88e 05 a 1.00e+ 06 a Acetonitrile ( methyl cyanide) 75 05 8 1.34E 01 e 1.41E 05 e 3.46e 05 a 1.00e+ 06 a Acrolein 107 02 8 1.12E 01 e 1.22E 05 e 1.22e 04 a 2.13e+ 05 a Acrylamide 79 06 1 1.07E 01 e 1.26E 05 e 1.00e 09 a 6.40e+ 05 a Acrylic acid ( propenoic acid) 79 10 7 1.03E 01 e 1.20E 05 e 1.17e 07 a 1.00e+ 06 a Acrylonitrile 107 13 1 1.14E 01 e 1.23E 05 e 1.03e 04 a 7.40e+ 04 a Aldrin 309 00 2 2.28E 02 e 5.84E 06 e 1.70e 04 a 1.80e 01 a Aniline ( benzeneamine) 62 53 3 8.30E 02 e 1.01E 05 e 1.90e 06 a 3.60e+ 04 a Benz( a) anthracene 56 55 3 5.09E 02 b 5.89E 06 b 3.35e 06 a 9.40e 03 a Benzene 71 43 2 8.95E 02 e 1.03E 05 e 5.55e 03 a 1.75e+ 03 a Benzidine 92 87 5 3.55E 02 e 7.59E 06 e 3.88e 11 a 5.00e+ 02 a Benzo( a) pyrene 50 32 8 2.55E 02 e 6.58E 06 e 1.13e 06 a 1.62e 03 a Benzo( b) fluoranthene 205 99 2 4.76E 02 b 5.51E 06 b 1.11e 04 a 1.50e 03 a Benzyl chloride 100 44 7 6.34E 02 e 8.81E 06 e 4.15e 04 a 5.25e+ 02 a Bis( 2 ethylhexyl) phthalate 117 81 7 1.73E 02 e 4.18E 06 e 1.02e 07 a 3.40e 01 a Bis( 2 chloroethyl) ether 111 44 4 5.67E 02 e 8.71E 06 e 1.80e 05 a 1.72e+ 04 a Bis( 2 chloroisopropyl) ether 39638 32 9 4.01E 02 e 7.40E 06 e 1.34e 04 d 1.31e+ 03 a Bromodichloromethane 75 27 4 5.63E 02 e 1.07E 05 e 1.60e 03 a 6.74e+ 03 a Bromomethane ( methyl bromide) 74 83 9 1.00E 01 e 1.35E 05 e 6.24e 03 a 1.52e+ 04 a Butadiene, 1,3 106 99 0 1.00E 01 e 1.03E 05 e 7.36e 02 a 7.35e+ 02 a Carbon tetrachloride 56 23 5 5.71E 02 e 9.78E 06 e 3.04e 02 a 7.93e+ 02 a Carbon disulfide 75 15 0 1.06E 01 e 1.30E 05 e 3.03e 02 a 1.19e+ 03 a Chlordane 57 74 9 2.15E 02 e 5.45E 06 e 4.86e 05 a 5.60e 02 a Chloro 1,3 butadiene, 2 ( Chloroprene) 126 99 8 8.41E 02 e 1.00E 05 e 1.19e 02 f 1.74e+ 03 a Chlorobenzene 108 90 7 7.21E 02 e 9.48E 06 e 3.70e 03 a 4.72e+ 02 a Chlorobenzilate 510 15 6 2.18E 02 e 5.48E 06 e 7.24e 08 f 1.11e+ 01 a Chlorodibromomethane 124 48 1 3.66E 02 e 1.06E 05 e 7.83e 04 a 2.60e+ 03 a Chloroethane ( ethyl chloride) 75 00 3 1.04E 01 e 1.16E 05 e 8.82e 03 a 5.68e+ 03 a Chloroform 67 66 3 7.70E 02 e 1.09E 05 e 3.67e 03 a 7.92e+ 03 a Chloromethane ( methyl chloride) 74 87 3 1.24E 01 e 1.36E 05 e 8.82e 03 a 5.33e+ 03 a Chlorophenol, 2 95 57 8 6.61E 02 e 9.48E 06 e 3.91e 04 a 2.20e+ 04 a Chloropropene, 3 ( allyl chloride) 107 05 1 9.36E 02 e 1.08E 05 e 1.10e 02 a 3.37e+ 03 a Chrysene 218 01 9 2.61E 02 e 6.75E 06 e 9.46e 05 a 1.60e 03 a Cresol, o 95 48 7 7.59E 02 e 9.86E 06 e 1.20e 06 a 2.60e+ 04 a Cresol, m 108 39 4 7.29E 02 e 9.32E 06 e 8.65e 07 a 2.27e+ 04 a ( continued) Table B 1. ( continued) Memo Attachment B Contaminant CASRN Da ( cm2/ s) Dw ( cm2/ s) HLC ( atm m3/ mol) Sol ( mg/ L)

Page 5 of 9 Cresol, p 106 44 5 7.24E 02 e 9.24E 06 e 7.92e 07 a 2.15e+ 04 a Cresols ( total) 1319 77 3 7.37E 02 e 9.48E 06 e 9.52e 07 a 2.34e+ 04 a Cumene 98 82 8 6.02E 02 e 7.85E 06 e 1.16e+ 00 a 6.13e+ 01 a Cyclohexanol 108 93 0 7.59E 02 e 9.35E 06 e 1.02e 04 f 4.30e+ 04 f DDT, p, p' 50 29 3 1.83E 02 e 4.44E 06 e 8.10e 06 a 2.50e 02 a Dibenz( a, h) anthracene 53 70 3 2.36E 02 e 6.02E 06 e 1.47e 08 a 2.49e 03 a Dibromo 3 chloropropane, 1,2 96 12 8 3.21E 02 e 8.90E 06 e 1.47e 04 a 1.23e+ 03 a Dichlorobenzene, 1,2 95 50 1 5.62E 02 e 8.92E 06 e 1.90e 03 a 1.56e+ 02 a Dichlorobenzene, 1,4 106 46 7 5.50E 02 e 8.68E 06 e 2.40e 03 a 7.38e+ 01 a Dichlorobenzidine, 3,3' 91 94 1 4.75E 02 b 5.50E 06 b 4.00e 09 a 3.11e+ 00 a Dichlorodifluoromethane ( Freon 12) 75 71 8 7.60E 02 e 1.08E 05 e 3.43e 01 a 2.80e+ 02 a Dichloroethane, 1,1 75 34 3 8.36E 02 e 1.06E 05 e 5.62e 03 a 5.06e+ 03 a Dichloroethane, 1,2 107 06 2 8.54E 02 e 1.09E 05 e 9.79e 04 a 8.52e+ 03 a Dichloroethylene, 1,1 75 35 4 8.63E 02 e 1.10E 05 e 2.61e 02 a 2.25e+ 03 a Dichloropropane, 1,2 78 87 5 7.33E 02 e 9.73E 06 e 2.80e 03 a 2.80e+ 03 a Dichloropropene, trans 1,3 10061 02 6 7.63E 02 e 1.01E 05 e 1.80e 03 i 2.72e+ 03 a Dichloropropene, 1,3 ( isomer mixture) 542 75 6 7.63E 02 e 1.01E 05 e 1.77e 02 a 2.80e+ 03 a Dichloropropene, cis 1,3 10061 01 5 7.65E 02 e 1.02E 05 e 2.40e 03 i 2.72e+ 03 a Dieldrin 60 57 1 2.33E 02 e 6.01E 06 e 1.51e 05 a 1.95e 01 a Dimethyl formamide, N, N ( DMF) 68 12 2 9.72E 02 e 1.12E 05 e 7.39e 08 i 1.00e+ 06 f Dimethylbenz( a) anthracene, 7,12 57 97 6 4.71E 02 b 5.45E 06 b 3.11e 08 a 2.50e 02 a Dinitrotoluene, 2,4 121 14 2 3.75E 02 e 7.90E 06 e 9.26e 08 a 2.70e+ 02 a Dioxane, 1,4 123 91 1 8.74E 02 e 1.05E 05 e 4.80e 06 a 1.00e+ 06 a Diphenylhydrazine, 1,2 122 66 7 0.0343 e 7.25E 06 e 1.53e 06 a 6.80e+ 01 a Epichlorohydrin 106 89 8 0.0888 e 1.11E 05 e 3.04e 05 a 6.59e+ 04 a Epoxybutane, 1,2 106 88 7 9.32E 02 e 1.05E 05 e 1.80e 04 f 9.50e+ 04 f Ethoxyethanol acetate, 2 111 15 9 5.70E 02 e 7.98E 06 e 1.80e 06 i 2.29e+ 05 i Ethoxyethanol , 2 110 80 5 8.19E 02 e 9.76E 06 e 1.23e 07 a 1.00e+ 06 a Ethylbenzene 100 41 4 6.86E 02 e 8.48E 06 e 7.88e 03 a 1.69e+ 02 a Ethylene dibromide ( 1,2 dibromoethane) 106 93 4 4.31E 02 e 1.05E 05 e 7.43e 04 a 4.18e+ 03 a Ethylene glycol 107 21 1 1.17E 01 e 1.36E 05 e 6.00e 08 a 1.00e+ 06 a Ethylene thiourea 96 45 7 8.69E 02 b 1.01E 05 b 3.08e 10 a 6.20e+ 04 a Ethylene oxide 75 21 8 1.34E 01 e 1.46E 05 e 1.48e 04 f 1.00e+ 06 g Formaldehyde 50 00 0 1.67E 01 e 1.74E 05 e 3.36e 07 a 5.50e+ 05 a Furfural 98 01 1 8.53E 02 e 1.07E 05 e 4.00e 06 a 1.10e+ 05 a HCH, gamma ( Lindane) 58 89 9 2.74E 02 e 7.30E 06 e 1.40e 05 a 6.80e+ 00 a ( continued) Table B 1. ( continued) Memo Attachment B Contaminant CASRN Da ( cm2/ s) Dw ( cm2/ s) HLC ( atm m3/ mol) Sol ( mg/ L)

Page 6 of 9 HCH, beta 319 85 7 0.0277 e 7.40E 06 e 7.43e 07 a 2.40e 01 a HCH, alpha 319 84 6 2.75E 02 e 7.35E 06 e 1.06e 05 a 2.00e+ 00 a Heptachlor epoxide 1024 57 3 2.19E 02 e 5.58E 06 e 9.50e 06 a 2.00e 01 a Heptachlor 76 44 8 2.23E 02 e 5.70E 06 e 1.10e 03 a 1.80e 01 a Hexachloro 1,3 butadiene 87 68 3 2.67E 02 e 7.03E 06 e 8.15e 03 a 3.23e+ 00 a Hexachlorobenzene 118 74 1 2.90E 02 e 7.85E 06 e 1.32e 03 a 5.00e 03 a Hexachlorocyclopentadiene 77 47 4 2.72E 02 e 7.22E 06 e 2.70e 02 a 1.80e+ 00 a Hexachlorodibenzo p dioxins ( HxCDDs) 34465 46 8 4.27E 02 j 4.12E 06 b 1.10e 05 c 4.40e 06 c Hexachlorodibenzofurans ( HxCDFs) 55684 94 1 4.36E 02 j 4.23E 06 b 1.10e 05 c 1.30e 05 c Hexachloroethane 67 72 1 3.21E 02 e 8.89E 06 e 3.89e 03 a 5.00e+ 01 a Hexane, n 110 54 3 7.28E 02 e 8.12E 06 e 1.43e 02 a 1.24e+ 01 a Indeno( 1,2,3 cd) pyrene 193 39 5 4.48E 02 b 5.19E 06 b 1.60e 06 a 2.20e 05 a Isophorone 78 59 1 5.25E 02 e 7.53E 06 e 6.64e 06 a 1.20e+ 04 a Mercury 7439 97 6 7.15E 02 e 3.01E 05 e 7.10e 03 k 5.62e 02 h Methacrylonitrile 126 98 7 9.64E 02 e 1.06E 05 e 2.47e 04 a 2.54e+ 04 a Methanol 67 56 1 1.58E 01 e 1.65E 05 e 4.55e 06 a 1.00e+ 06 a Methoxyethanol acetate, 2 110 49 6 6.59E 02 e 8.71E 06 e 3.11e 07 d 1.00e+ 06 i Methoxyethanol, 2 109 86 4 0.0952 e 1.10E 05 e 8.10e 08 f 1.00e+ 06 g Methyl methacrylate 80 62 6 7.53E 02 e 9.25E 06 e 3.37e 04 a 1.50e+ 04 a Methyl tert butyl ether ( MTBE) 1634 04 4 7.55E 02 e 8.63E 06 e 5.87e 04 f 5.13e+ 04 f Methyl isobutyl ketone 108 10 1 6.98E 02 e 8.36E 06 e 1.38e 04 a 1.90e+ 04 a Methyl ethyl ketone 78 93 3 9.17E 02 e 1.02E 05 e 5.59e 05 a 2.23e+ 05 a Methylcholanthrene, 3 56 49 5 2.41E 02 e 6.14E 06 e 9.40e 07 a 3.23e 03 a Methylene chloride ( dichloromethane) 75 09 2 9.99E 02 e 1.25E 05 e 2.19e 03 a 1.30e+ 04 a N Nitrosomethylethylamine 10595 95 6 8.41E 02 e 9.99E 06 e 1.40e 06 i 1.97e+ 04 a N Nitrosodimethylamine 62 75 9 9.88E 02 e 1.15E 05 e 1.20e 06 a 1.00e+ 06 a N Nitrosopiperidine 100 75 4 6.99E 02 e 9.18E 06 e 2.80e 07 a 7.65e+ 04 a N Nitrosodiphenylamine 86 30 6 2.84E 02 e 7.19E 06 e 5.00e 06 a 3.51e+ 01 a N Nitrosodiethylamine 55 18 5 7.38E 02 e 9.13E 06 e 3.63e 06 a 9.30e+ 04 a N Nitroso di n butylamine 924 16 3 4.22E 02 e 6.83E 06 e 3.16e 04 a 1.27e+ 03 a N Nitrosopyrrolidine 930 55 2 8.00E 02 e 1.01E 05 e 1.20e 08 a 1.00e+ 06 a N Nitroso di n propylamine 621 64 7 5.64E 02 e 7.76E 06 e 2.25e 06 a 9.89e+ 03 a Naphthalene 91 20 3 6.05E 02 e 8.38E 06 e 4.83e 04 a 3.10e+ 01 a Nitrobenzene 98 95 3 6.81E 02 e 9.45E 06 e 2.40e 05 a 2.09e+ 03 a Nitropropane, 2 79 46 9 8.47E 02 e 1.02E 05 e 1.23e 04 a 1.70e+ 04 a ( continued) Table B 1. ( continued) Memo Attachment B Contaminant CASRN Da ( cm2/ s) Dw ( cm2/ s) HLC ( atm m3/ mol) Sol ( mg/ L)

Page 7 of 9 Pentachlorodibenzo p dioxins ( PeCDDs) 36088 22 9 4.47E 02 j 4.38E 06 b 2.60e 06 c 1.18e 04 c Pentachlorodibenzofurans ( PeCDFs) 30402 15 4 4.57E 02 j 4.51E 06 b 5.00e 06 c 2.40e 04 c Pentachlorophenol 87 86 5 2.95E 02 e 8.01E 06 e 2.44e 08 a 1.95e+ 03 a Phenol 108 95 2 8.34E 02 e 1.03E 05 e 3.97e 07 a 8.28e+ 04 a Phthalic anhydride 85 44 9 5.95E 02 e 9.75E 06 e 1.63e 08 a 6.20e+ 03 a Polychlorinated biphenyls ( Aroclors) 1336 36 3 2.33E 02 e 5.98E 06 e 2.60e 03 a 7.00e 02 a Propylene oxide ( 1,2 epoxypropane) 75 56 9 1.10E 01 e 1.21E 05 e 1.23e 04 f 4.05e+ 05 f Pyridine 110 86 1 9.31E 02 e 1.09E 05 e 8.88e 06 a 1.00e+ 06 a Styrene 100 42 5 7.13E 02 e 8.81E 06 e 2.75e 03 a 3.10e+ 02 a TCDD, 2,3,7,8 1746 01 6 4.70E 02 j 4.68E 06 b 3.29e 05 c 1.93e 05 c Tetrachlorodibenzo p dioxins ( TCDDs) 41903 57 5 4.70E 02 j 4.68E 06 b 1.70e 05 c 3.30e 04 c Tetrachlorodibenzofurans ( TCDFs) 55722 27 5 4.82E 02 j 4.84E 06 b 1.40e 05 c 4.20e 04 c Tetrachloroethane, 1,1,2,2 79 34 5 4.89E 02 e 9.29E 06 e 3.45e 04 a 2.97e+ 03 a Tetrachloroethane, 1,1,1,2 630 20 6 4.82E 02 e 9.10E 06 e 2.42e 03 a 1.10e+ 03 a Tetrachloroethylene 127 18 4 5.05E 02 e 9.45E 06 e 1.84e 02 a 2.00e+ 02 a Toluene 108 88 3 7.80E 02 e 9.23E 06 e 6.64e 03 a 5.26e+ 02 a Toluenediamine 2,4 95 80 7 7.72E 02 b 8.94E 06 b 7.92e 10 a 3.37e+ 04 a Toluidine, o 95 53 4 7.24E 02 e 9.18E 06 e 2.72e 06 a 1.66e+ 04 a Toxaphene ( chlorinated camphenes) 8001 35 2 2.16E 02 e 5.48E 06 e 6.00e 06 a 7.40e 01 a Tribromomethane ( bromoform) 75 25 2 3.58E 02 e 1.04E 05 e 5.35e 04 a 3.10e+ 03 a Trichloro 1,2,2 trifluoro ethane, 1,1,2 76 13 1 3.76E 02 e 8.59E 06 e 4.81e 01 a 1.70e+ 02 a Trichlorobenzene, 1,2,4 120 82 1 3.96E 02 e 8.40E 06 e 1.42e 03 a 3.46e+ 01 a Trichloroethane, 1,1,2 79 00 5 6.69E 02 e 1.00E 05 e 9.13e 04 a 4.42e+ 03 a Trichloroethane, 1,1,1 71 55 6 6.48E 02 e 9.60E 06 e 1.72e 02 a 1.33e+ 03 a Trichloroethylene ( TCE) 79 01 6 6.87E 02 e 1.02E 05 e 1.03e 02 a 1.10e+ 03 a Trichlorofluoromethane ( Freon 11) 75 69 4 6.55E 02 e 1.01E 05 e 9.70e 02 a 1.10e+ 03 a Trichlorophenol, 2,4,6 88 06 2 3.14E 02 e 8.09E 06 e 7.79e 06 a 8.00e+ 02 a Trichloropropane, 1,2,3 96 18 4 5.75E 02 e 9.24E 06 e 4.09e 04 a 1.75e+ 03 a Triethylamine 121 44 8 6.63E 02 e 7.84E 06 e 1.38e 04 f 5.50e+ 04 f Vinyl acetate 108 05 4 8.51E 02 e 1.00E 05 e 5.11e 04 a 2.00e+ 04 a Vinyl chloride 75 01 4 1.07E 01 e 1.20E 05 e 2.70e 02 a 2.76e+ 03 a Xylene, p 106 42 3 6.84E 02 e 8.45E 06 e 7.66e 03 a 1.85e+ 02 a Xylene, o 95 47 6 6.91E 02 e 8.56E 06 e 5.19e 03 a 1.78e+ 02 a Xylene, m 108 38 3 6.85E 02 e 8.47E 06 e 7.34e 03 a 1.61e+ 02 a Xylenes ( total) 1330 20 7 6.87E 02 e 8.49E 06 e 6.73e 03 a 1.75e+ 02 a ( continued) Table B 1. ( continued) Memo Attachment B Page 8 of 9 Da = air diffusivity; Dw = water diffusivity; HLC = Henry's law constant; Sol = aqueous solubility CASRN = Chemical Abstract Service Registry Number Data Sources: a SCDM ( U. S. EPA, 1997b). b Calculated based on U. S. EPA, 1987. c U. S. EPA, 2000. d Calculated based on Lyman, Reehl, and Rosenblatt, 1990. e Calculated based on WATER9 ( U. S. EPA, 2001). f CHEMFATE ( SRC, 1999). g ChemFinder. com ( CambridgeSoft Corporation, 2001). h The Merck Index ( Budavari, 1996). i HSDB ( NLM, 2001). j Calculated based on U. S. EPA, 2000. k U. S. EPA, 1997a.

B. 6 References Budavari, S. ( ed). 1996. The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals. 12th edition. Whitehouse Station, NJ: Merck and Co.

CambridgeSoft Corporation. 2001. ChemFinder. com database and internet searching. http:// chemfinder. cambridgesoft. com. Accessed July 2001.

Lyman, W. J., W. F. Reehl, and D. H. Rosenblatt. 1990. Handbook of Chemical Property Estimation Methods: Environmental Behavior of Organic Compounds. Washington, DC: American Chemical Society.

Syracuse Research Corporation ( SRC). 1999. CHEMFATE Chemical Search, Environmental Science Center, Syracuse, NY. http:// esc. syrres. com/ efdb/ Chemfate. htm. Accessed July 2001.

U. S. Environmental Protection Agency ( EPA). 1987. Process Coefficients and Models for Simulating Toxic Organics and Heavy Metals in Surface Waters. Office of Research and Development. Washington, DC: U. S. Government Printing Office ( GPO).

U. S. Environmental Protection Agency ( EPA). 1997a. Mercury Study Report to Congress. Volume IV: An Assessment of Exposure to Mercury in the United States. EPA 452/ R 97 006. Office of Air Quality Planning and Standards and Office of Research and Development. Washington, DC: GPO.

U. S. Environmental Protection Agency ( EPA). 1997b. Superfund Chemical Data Matrix ( SCDM). SCDMWIN 1.0 ( SCDM Windows User's Version), Version 1. Office of Solid Waste and Emergency Response, Washington DC: GPO. http:// www. epa. gov/ superfund/ resources/ scdm/ index. htm. Accessed July 2001. Memo Attachment B Page 9 of 9 U. S. Environmental Protection Agency ( EPA). 2000. Exposure and Human Health Reassessment of 2,3,7,8 Tetrachlorodibenzo p Dioxin ( TCDD) and Related Compounds, Part 1, Vol. 3. Office of Research and Development, Washington, DC: GPO.

U. S. Environmental Protection Agency ( EPA). 2001. WATER9. Office of Air Quality Planning and Standards, Research Triangle Park, NC. http:// www. epa. gov/ ttn/ chief/ software/ water/ index. html. Accessed July 2001.

U. S. National Library of Medicine ( NLM). 2001. Hazardous Substances Data Bank ( HSDB). http:// toxnet. nlm. nih. gov/ cgi bin/ sis/ htmlgen? HSDB. Accessed July 2001. This page intentionally left blank. Attachment A 2 Listing of Input Specifications for Each Unit from WATER9 This page intentionally left blank. Page 1 of 17 Attachment A. 1 Listing of Input Specifications for Each Unit from WATER9 Non aerated units Run 1 ( Tank and SI)

Type of unit is storage tank 1 Description of unit 12 RUN1 TANK 2 Wastewater temperature ( C) 24.52 3 Open surface area of tank ( m2) 0.9 4 Density of liquid in tank ( g/ cc) 1 5 tank waste Mwt, water= 18 18 6 tank storage time ( days) 0 7 tank paint factor 1 8 tank diameter ( m) 1.1 9 tank vapor space height ( m) 0 10 diurnal temp. change ( deg. C) 11 11 tank height ( m) 2 12 oil in composite wastewater ( wt. %) 0 Type of unit is lagoon 1 Description of unit 13 RUN1 SI 2 Wastewater temperature ( C) 24.52 3 Length of impoundment ( m) 6 4 Depth of impoundment ( m) 0.1 5 Width of impoundment ( m) 6 6 active biomass, impoundment ( g/ l) 0 7 if there is plug flow, enter 1 0 8 time for emissions in lagoon ( months) 0 9 Overall biorate ( mg/ g bio hr) 19 Type of unit is solids removal stream 1 Description of unit 14 RUN1 TANK SOLIDS 2 flow diversion rate ( l/ s) 3.66E 06 3 fraction solids in waste diverted 0.63 Type of unit is hard piped, no headspace 1 Description of unit 16 RUN1 TANK PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 17 RUN1 TANK PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is solids removal stream 1 Description of unit 18 RUN1 SI SOLIDS 2 flow diversion rate ( l/ s) 3.66E 06 3 fraction solids in waste diverted 0.63 Type of unit is hard piped, no headspace 1 Description of unit 20 RUN1 SI PIPE Page 2 of 17 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 21 RUN1 SI PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Page 3 of 17 Non aerated Units Run 2 ( SI only)

Type of unit is hard piped, no headspace 1 Description of unit 24 RUN2 SI PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 25 RUN2 SI PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is lagoon 1 Description of unit 26 RUN2 SI 2 Wastewater temperature ( C) 24.52 3 Length of impoundment ( m) 8 4 Depth of impoundment ( m) 0.2 5 Width of impoundment ( m) 8 6 active biomass, impoundment ( g/ l) 0.03 7 if there is plug flow, enter 1 0 8 time for emissions in lagoon ( months) 0 9 Overall biorate ( mg/ g bio hr) 19 Type of unit is solids removal stream 1 Description of unit 27 RUN2 SI SOLIDS 2 flow diversion rate ( l/ s) 6.39E 06 3 fraction solids in waste diverted 0.63 Page 4 of 17 Non aerated Units Run 3 ( Tank and SI)

Type of unit is storage tank 1 Description of unit 12 RUN3 TANK 2 Wastewater temperature ( C) 24.52 3 Open surface area of tank ( m2) 6.6 4 Density of liquid in tank ( g/ cc) 1 5 tank waste Mwt, water= 18 18 6 tank storage time ( days) 0 7 tank paint factor 1 8 tank diameter ( m) 2.9 9 tank vapor space height ( m) 0 10 diurnal temp. change ( deg. C) 11 11 tank height ( m) 2.6 12 oil in composite wastewater ( wt. %) 0 Type of unit is lagoon 1 Description of unit 13 RUN3 SI 2 Wastewater temperature ( C) 24.52 3 Length of impoundment ( m) 48 4 Depth of impoundment ( m) 0.9 5 Width of impoundment ( m) 48 6 active biomass, impoundment ( g/ l) 0 7 if there is plug flow, enter 1 0 8 time for emissions in lagoon ( months) 0 9 Overall biorate ( mg/ g bio hr) 19 Type of unit is solids removal stream 1 Description of unit 14 RUN3 TANK SOLIDS 2 flow diversion rate ( l/ s) 0.00134 3 fraction solids in waste diverted 0.63 Type of unit is hard piped, no headspace 1 Description of unit 16 RUN3 TANK PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 17 RUN3 TANK PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is solids removal stream 1 Description of unit 18 RUN3 SI SOLIDS 2 flow diversion rate ( l/ s) 0.00134 3 fraction solids in waste diverted 0.63 Type of unit is hard piped, no headspace 1 Description of unit 20 RUN3 SI PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 Page 5 of 17 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 21 RUN3 SI PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Page 6 of 17 Non aerated Units Run 4 ( SI only)

Type of unit is hard piped, no headspace 1 Description of unit 24 RUN4 SI PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 25 RUN4 SI PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is lagoon 1 Description of unit 26 RUN4 SI 2 Wastewater temperature ( C) 24.52 3 Length of impoundment ( m) 17 4 Depth of impoundment ( m) 0.4 5 Width of impoundment ( m) 17 6 active biomass, impoundment ( g/ l) 0.03 7 if there is plug flow, enter 1 0 8 time for emissions in lagoon ( months) 0 9 Overall biorate ( mg/ g bio hr) 19 Type of unit is solids removal stream 1 Description of unit 27 RUN4 SI SOLIDS 2 flow diversion rate ( l/ s) 0.00137 3 fraction solids in waste diverted 0.63 Page 7 of 17 Non aerated Units Run 5 ( Tank and SI)

Type of unit is storage tank 1 Description of unit 12 RUN5 TANK 2 Wastewater temperature ( C) 24.52 3 Open surface area of tank ( m2) 6 4 Density of liquid in tank ( g/ cc) 1 5 tank waste Mwt, water= 18 18 6 tank storage time ( days) 0 7 tank paint factor 1 8 tank diameter ( m) 2.7 9 tank vapor space height ( m) 0 10 diurnal temp. change ( deg. C) 11 11 tank height ( m) 2.5 12 oil in composite wastewater ( wt. %) 0 Type of unit is lagoon 1 Description of unit 13 RUN5 SI 2 Wastewater temperature ( C) 24.52 3 Length of impoundment ( m) 8 4 Depth of impoundment ( m) 0.2 5 Width of impoundment ( m) 8 6 active biomass, impoundment ( g/ l) 0 7 if there is plug flow, enter 1 0 8 time for emissions in lagoon ( months) 0 9 Overall biorate ( mg/ g bio hr) 19 Type of unit is solids removal stream 1 Description of unit 14 RUN5 TANK SOLIDS 2 flow diversion rate ( l/ s) 1.84E 06 3 fraction solids in waste diverted 0.99 Type of unit is hard piped, no headspace 1 Description of unit 16 RUN5 TANK PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 17 RUN5 TANK PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is solids removal stream 1 Description of unit 18 RUN5 SI SOLIDS 2 flow diversion rate ( l/ s) 1.84E 06 3 fraction solids in waste diverted 0.99 Type of unit is hard piped, no headspace 1 Description of unit 20 RUN5 SI PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 Page 8 of 17 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 21 RUN5 SI PIPE 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Page 9 of 17 Aerated Treatment Train Run 7 Type of unit is hard piped, no headspace 1 Description of unit 1 inlet pipe 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 2 transfer pipe 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is primary municipal clarifier 1 Description of unit 4 Primary clarifier 2 Wastewater temperature ( C) 25 3 primary clarifier diameter ( m) 1 4 primary clarifier depth ( m) 2 5 clarifier solids removal efficiency 0.6 6 waterfall drop height ( cm) 20 7 clarifier weir/ circumference 0.5 8 Center well present, = 1 1 10 number of identical units in parallel 0 15 vent air emission control factor 0 16 cover vent rate ( m3/ s per m2 surface) 0.0005 17 If covered, then enter 1 0 Type of unit is activated sludge 1 Description of unit 5 Activated Sludge 2 Wastewater temperature ( C) 25 3 length of aeration unit ( m) 1 4 width of aeration unit ( m) 1 5 depth of aeration unit ( m) 3.5 6 Area of agitation ( each aerator, m2) 1 7 Total number of agitators in the unit 1 8 Power of agitation ( each aerator, HP) 0.014 9 Impeller diameter ( cm) 60 10 Impeller rotation ( RPM) 1200 11 Agitator mechanical efficiency 0.83 12 aerator effectiveness, alpha 0.83 13 if there is plug flow, enter 1 0 14 Overall biorate ( mg/ g bio hr) 19 15 Aeration air flow ( m3/ s) 0.001 16 activated sludge biomass( g/ l) 2.5 17 If covered, then enter 1 0 18 agitator pump rate( m3/ s each) 0 Type of unit is circular clarifier 1 Description of unit 6 Secondary Clarifier 2 Wastewater temperature ( C) 25 3 secondary clarifier diameter ( m) 1 4 secondary clarifier depth ( m) 3 5 clarifier solids removal efficiency 0.99 Page 10 of 17 6 waterfall drop height ( cm) 20 7 clarifier weir/ circumference 0.5 Type of unit is solids removal stream 1 Description of unit 7 SecClar sludge split 2 flow diversion rate ( l/ s) 0.12 3 fraction solids in waste diverted 0.99 Type of unit is hard piped, no headspace 1 Description of unit 8 SecClar sludge split 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 9 Sludge recycle 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is divert flow 1 Description of unit 10 SecClar wasted sludge 2 flow diversion rate ( l/ s) 0.007 4 fraction waste flow diverted 0 Type of unit is hard piped, no headspace 1 Description of unit 11 SecClar wasted sludge 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is solids removal stream 1 Description of unit 12 PrimClar sludge 2 flow diversion rate ( l/ s) 0.007 3 fraction solids in waste diverted 0.6 Type of unit is hard piped, no headspace 1 Description of unit 13 PrimClar sludge 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 40 Act sludge effluent 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 Page 11 of 17 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 41 SecClar effluent 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Page 12 of 17 Aerated Treatment Train Run 8 Type of unit is hard piped, no headspace 1 Description of unit 42 inlet pipe 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 43 transfer pipe 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is primary municipal clarifier 1 Description of unit 45 primary clarifier 2 Wastewater temperature ( C) 25 3 primary clarifier diameter ( m) 3 4 primary clarifier depth ( m) 3.8 5 clarifier solids removal efficiency 0.6 6 waterfall drop height ( cm) 20 7 clarifier weir/ circumference 0.5 8 Center well present, = 1 1 10 number of identical units in parallel 0 15 vent air emission control factor 0 16 cover vent rate ( m3/ s per m2 surface) 0.0005 17 If covered, then enter 1 0 Type of unit is activated sludge 1 Description of unit 46 Activated Sludge 2 Wastewater temperature ( C) 25 3 length of aeration unit ( m) 5.2 4 width of aeration unit ( m) 3.5 5 depth of aeration unit ( m) 5 6 Area of agitation ( each aerator, m2) 47 7 Total number of agitators in the unit 1 8 Power of agitation ( each aerator, HP) 0.34 9 Impeller diameter ( cm) 60 10 Impeller rotation ( RPM) 1200 11 Agitator mechanical efficiency 0.83 12 aerator effectiveness, alpha 0.83 13 if there is plug flow, enter 1 0 14 Overall biorate ( mg/ g bio hr) 19 15 Aeration air flow ( m3/ s) 0.026 16 activated sludge biomass( g/ l) 2.5 17 If covered, then enter 1 0 18 agitator pump rate( m3/ s each) 0 Type of unit is circular clarifier 1 Description of unit 47 Secondary Clarifie 2 Wastewater temperature ( C) 25 3 secondary clarifier diameter ( m) 4 4 secondary clarifier depth ( m) 4 5 clarifier solids removal efficiency 0.99 Page 13 of 17 6 waterfall drop height ( cm) 20 7 clarifier weir/ circumference 0.5 Type of unit is solids removal stream 1 Description of unit 48 SecClar sludge split 2 flow diversion rate ( l/ s) 0.12 3 fraction solids in waste diverted 0.99 Type of unit is hard piped, no headspace 1 Description of unit 49 SecClar sludge split 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Total water added at the unit ( l/ s) 50 SecClar sludge recycle 2 Area of openings at unit ( cm2) 50 3 Radius of drop pipe ( cm) 5 4 Drop length to conduit ( cm) 61 5 Humidity of inlet air (%) 60 6 Temperature of air ( C) 10.16 7 Drain air velocity ( ft/ min) 84 8 manhole air velocity ( ft/ min) 128 9 Conduit air velocity ( ft/ min) 66 10 Wind velocity ( cm/ s at 10 m) 377 11 distance to next unit ( cm) 500 12 slope of underflow conduit .015 13 friction factor liquid .016 14 friction factor gas .006 15 radius of underflow conduit ( cm) 12 16 Underflow T ( C) 25 17 oscillation cycle time ( min) 5 18 design collection velocities ( ft/ s) 2 Type of unit is divert flow 1 Description of unit 51 SecClar wasted sludge 8 oil molecular weight 180 9 oil density ( g/ cc) .8 10 NaUT 1= municipal 2= industrial 0 11 NaUT 1= mass tr. 2= equil 0 Type of unit is hard piped, no headspace 1 Description of unit 52 SecClar wasted sludge 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is solids removal stream 1 Description of unit 53 PrimClar sludge 2 flow diversion rate ( l/ s) 0.007 3 fraction solids in waste diverted 0.6 Type of unit is hard piped, no headspace 1 Description of unit 54 PrimClar sludge 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 Page 14 of 17 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 81 Act sludge effluent 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 82 SecClar effluent 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Page 15 of 17 Aerated Treatment Train Run 9 Type of unit is hard piped, no headspace 1 Description of unit 1 inlet pipe 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 2 transfer pip 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is primary municipal clarifier 1 Description of unit 4 primary clarifier 2 Wastewater temperature ( C) 25 3 primary clarifier diameter ( m) 1 4 primary clarifier depth ( m) 2 5 clarifier solids removal efficiency 0.6 6 waterfall drop height ( cm) 20 7 clarifier weir/ circumference 0.5 8 Center well present, = 1 1 10 number of identical units in parallel 0 15 vent air emission control factor 0 16 cover vent rate ( m3/ s per m2 surface) 0.0005 17 If covered, then enter 1 0 Type of unit is activated sludge 1 Description of unit 5 Activated Sludge 2 Wastewater temperature ( C) 25 3 length of aeration unit ( m) 0.8 4 width of aeration unit ( m) 0.8 5 depth of aeration unit ( m) 2.5 6 Area of agitation ( each aerator, m2) 1 7 Total number of agitators in the unit 1 8 Power of agitation ( each aerator, HP) 0.006 9 Impeller diameter ( cm) 60 10 Impeller rotation ( RPM) 1200 11 Agitator mechanical efficiency 0.83 12 aerator effectiveness, alpha 0.83 13 if there is plug flow, enter 1 0 14 Overall biorate ( mg/ g bio hr) 19 15 Aeration air flow ( m3/ s) 0.00044 16 activated sludge biomass( g/ l) 2.5 17 If covered, then enter 1 0 18 agitator pump rate( m3/ s each) 0 Type of unit is circular clarifier 1 Description of unit 6 Secondary Clarifier 2 Wastewater temperature ( C) 25 3 secondary clarifier diameter ( m) 1 4 secondary clarifier depth ( m) 3 5 clarifier solids removal efficiency 0.99 Page 16 of 17 6 waterfall drop height ( cm) 20 7 clarifier weir/ circumference 0.5 Type of unit is solids removal stream 1 Description of unit 7 SecClar sludge split 2 flow diversion rate ( l/ s) 0.12 3 fraction solids in waste diverted 0.99 Type of unit is hard piped, no headspace 1 Description of unit 8 SecClar sludge split 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 9 SecClar Sludge recycle 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is divert flow 1 Description of unit 10 SecClar wasted sludge 2 flow diversion rate ( l/ s) 0.007 4 fraction waste flow diverted 0 Type of unit is hard piped, no headspace 1 Description of unit 11 SecClar wasted sludge 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is solids removal stream 1 Description of unit 12 PrimClar sludge 2 flow diversion rate ( l/ s) 0.007 3 fraction solids in waste diverted 0.6 Type of unit is hard piped, no headspace 1 Description of unit 13 PrimClar sludge 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 40 Act sludge effluent 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 Page 17 of 17 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 Type of unit is hard piped, no headspace 1 Description of unit 41 SecClar effluent 2 Underflow T ( C) 25 3 Total water added at the unit ( l/ s) 0 7 Open surface= 1 0 8 Subsurface entrance= 1 1 9 subsurface exit = 1 1 10 radius of underflow conduit ( cm) 12 11 distance to next unit ( cm) 500 12 slope of underflow conduit 0.015 This page intentionally left blank. Attachment A 3 Toxicity Benchmarks Used in the Industrial Waste Evaluation Model ( IWEM) This page intentionally left blank. Page 1 of 23 RESEARCH TRIANGLE INSTITUTE MEMORANDUM DATE: August 27, 2001 TO: Ann Johnson FROM: Susan N. Wolf, Robert S. Truesdale SUBJECT: Toxicity benchmarks used in the Industrial Waste Evaluation Model ( IWEM) ( revised)

Human health benchmarks for chronic oral and inhalation exposures were used in the Industrial Waste Evaluation Model ( IWEM). The U. S. Environmental Protection Agency ( EPA) uses reference doses ( RfDs) and reference concentrations ( RfCs) to evaluate noncancer risk from oral and inhalation exposures, respectively. Oral cancer slope factors ( CSFs), inhalation unit risk factors ( URFs), and inhalation CSFs are used to evaluate risk for carcinogens.

This memorandum provides the toxicity benchmarks used in IWEM. Section 1.0 describes the data sources and general hierarchy used to collect these benchmarks. Section 2.0 provides the benchmarks along with discussions of individual human health benchmarks extracted from a variety of sources.

1.0 Methodology and Data Sources Several sources of health benchmarks are available. Human health benchmarks were obtained from these sources in the following order of preference:

# Integrated Risk Information System ( IRIS) # Superfund Technical Support Center Provisional Benchmarks # Health Effects Assessment Summary Tables ( HEAST) # Agency for Toxic Substances and Disease Registry ( ATSDR) minimal risk levels ( MRLs) # California Environmental Protection Agency ( CalEPA) chronic inhalation reference exposure levels ( RELs) and cancer potency factors. # EPA health assessment documents # Various other EPA health benchmark sources.

For dioxins and dibenzofurans, World Health Organization ( WHO) toxicity equivalency factors ( TEFs) from Van den Berg et al. ( 1998) were applied to the HEAST CSF for 2,3,7,8 TCDD to get CSFs for all other dioxins and furans ( see Section 2.4). Page 2 of 23 # Integrated Risk Information System ( IRIS)

Benchmarks in IRIS are prepared and maintained by EPA, and values from IRIS were used in IWEM whenever available. IRIS is EPA's electronic database containing information on human health effects ( U. S. EPA, 2001a). Each chemical file contains descriptive and quantitative information on potential health effects. Health benchmarks for chronic noncarcinogenic health effects include RfDs and RfCs. Cancer classification, oral CSFs, and inhalation URFs are included for carcinogenic effects. IRIS is the official repository of Agencywide consensus of human health risk information.

Inhalation CSFs are not available from IRIS, so they were calculated from inhalation URFs ( which are available from IRIS) using the following equation:

In this equation, 70 kg represents average body weight; 20 m3/ d represents average inhalation rate; and 1000 : g/ mg is a units conversion factor ( U. S. EPA, 1997). These standard estimates of body weight and inhalation rate are used by EPA in the calculation of the URF, and, therefore, the values were used to calculate inhalation CSFs.

1.2 Superfund Provisional Benchmarks The Superfund Technical Support Center ( EPA's National Center for Environmental Assessment [ NCEA]) derives provisional RfCs, RfDs, and CSFs for certain chemicals. These provisional health benchmarks can be found in Risk Assessment Issue Papers. Some of the provisional values have been externally peer reviewed, and some ( e. g., trichloroethylene, tetrachloroethylene) come from previously published EPA Health Assessment Documents. These provisional values have not undergone EPA's formal review process for finalizing benchmarks and do not represent Agency wide consensus information. Specific provisional values used in IWEM are described in Section 2.5.

1.3 Health Effects Summary Tables ( HEAST)

HEAST is a listing of provisional noncarcinogenic and carcinogenic health toxicity values ( RfDs, RfCs, URFs, and CSFs) derived by EPA ( U. S. EPA, 1997). Although the health toxicity values in HEAST have undergone review and have the concurrence of individual EPA program offices, either they have not been reviewed as extensively as those in IRIS or their data set is not complete enough to be listed in IRIS. HEAST benchmarks have not been updated in several years and do not represent Agency wide consensus information. Page 3 of 23 1.4 ATSDR Minimal Risk Levels The ATSDR MRLs are substance specific health guidance levels for noncarcinogenic endpoints ( ATSDR, 2001). An MRL is an estimate of the daily human exposure to a hazardous substance that is likely to be without appreciable risk of adverse noncancer health effects over a specified duration of exposure. MRLs are based on noncancer health effects only and are not based on a consideration of cancer effects. MRLs are derived for acute, intermediate, and chronic exposure durations for oral and inhalation routes of exposure. Inhalation and oral MRLs are derived in a manner similar to EPA's RfCs and RfDs, respectively ( i. e., ATSDR uses the noobserved adverse effect level/ uncertainty factor ( NOAEL/ UF) approach); however, MRLs are intended to serve as screening levels and are exposure duration specific. Also, ATSDR uses EPA's 1994 inhalation dosimetry methodology in the derivation of inhalation MRLs. A chronic inhalation MRL for mixed xylenes was used as a surrogate for each of the xylene isomers.

1.5 CalEPA Cancer Potency Factors and Reference Exposure Levels CalEPA has developed cancer potency factors for chemicals regulated under California's Hot Spots Air Toxics Program ( CalEPA, 1999a). The cancer potency factors are analogous to EPA's oral and inhalation CSFs. CalEPA has also developed chronic inhalation RELs, analogous to EPA's RfC, for 120 substances ( CalEPA, 1999b, 2000). CalEPA used EPA's 1994 inhalation dosimetry methodology in the derivation of inhalation RELs. The cancer potency factors and inhalation RELs have undergone internal peer review by various California agencies and have been the subject of public comment. A chronic inhalation REL for mixed cresols was used as a surrogate for each of the cresol isomers.

1.6 Other EPA Health Benchmarks EPA has also derived health benchmark values in other risk assessment documents, such as Health Assessment Documents ( HADs), Health Effect Assessments ( HEAs), Health and Environmental Effects Profiles ( HEEPs), Health and Environmental Effects Documents ( HEEDs), Drinking Water Criteria Documents, and Ambient Water Quality Criteria Documents. Evaluations of potential carcinogenicity of chemicals in support of reportable quantity adjustments were published by EPA's Carcinogen Assessment Group ( CAG) and may include cancer potency factor estimates. Health toxicity values identified in these EPA documents are usually dated and are not recognized as Agency wide consensus information or verified benchmarks, however, and as a result they are used in the hierarchy only when values are not available from IRIS, HEAST, Superfund provisional values, ATSDR, or CalEPA. Section 2.6 describes the specific values from these alternative EPA sources that were used in IWEM.

2.0 IWEM Human Health Benchmarks The chronic human health benchmarks used to calculate the health based numbers ( HBNs) in IWEM are summarized in Table 1, which provides the Chemical Abstract Service Registry Number ( CASRN), constituent name, RfD ( mg/ kg d), RfC ( mg/ m3), oral CSF 1A twofold increase of the oral CSF to 1.4 per mg/ kg d to account for continuous lifetime exposure from birth was also recommended but was not used for IWEM.

2A twofold increase to 8.8E 6 per : g/ m3 for the inhalation URF, to account for continuous lifetime exposure from birth, was also recommended but was not used for IWEM.

Page 4 of 23 ( mg/ kg d 1), inhalation URF [(: g/ m3) 1], inhalation CSF ( mg/ kg d 1), and reference for each benchmark. A key to the references cited and abbreviations used is provided at the end of the table.

For a majority of IWEM constituents, human health benchmarks were available from IRIS ( U. S. EPA, 2001a), Superfund Provisional Benchmarks, or HEAST ( U. S. EPA, 1997). Benchmarks also were obtained from ATSDR ( 2001) or CalEPA ( 1999a, 1999b, 2000). This section describes benchmarks obtained from other sources, along with the Superfund Provisional values and special uses ( e. g., benzene, vinyl chloride) of IRIS benchmarks.

2.1 Benzene The cancer risk estimates for benzene are provided as ranges in IRIS. The oral CSF for benzene is 1.5E 02 to 5.5E 02 ( mg/ kg/ d) 1 and the inhalation URF is 2.2E 06 to 7.8E 06 ( µ g/ m3) 1 ( U. S. EPA, 2001a). For IWEM, the upper range estimates were used ( i. e., 5.5E 02 ( mg/ kg/ d) 1 and 7.8E 06 ( µ g/ m3) 1 for the oral CSF and inhalation URF, respectively).

2.2 Vinyl Chloride Based on use of the linearized multistage model, IRIS recommends an oral CSF of 7.2E 1 per mg/ kg d for vinyl chloride to account for continuous lifetime exposure during adulthood; this value was used for IWEM. 1 Based on use of the linearized multistage model, an inhalation URF of 4.4E 6 per : g/ m3 to account for continuous, lifetime exposure during adulthood was recommended for vinyl chloride and was used for IWEM; an inhalation CSF of 1.5E 2 per mg/ kg d was calculated from the URF. 2 2.3 Polychlorinated Biphenyls There are two inhalation CSFs available from IRIS for polychlorinated biphenyls ( PCBs): 0.4 per mg/ kg d for evaporated congeners and 2.0 per mg/ kg d for dust or aerosol ( high risk and persistence). The inhalation CSF for evaporated congeners will be used for IWEM. Page 5 of 23 Table 1. Human Health Benchmarks Used in IWEM Constituent Name CASRN RfD ( mg/ kg d) RfD Ref CSFo ( per mg/ kg d) CSFo Ref RfC ( mg/ m3) RfC Ref URF ( per ug/ m3) URF Ref CSFi ( per mg/ kg d) CSFi Ref Acenaphthene 83 32 9 6.0E 02 I Acetaldehyde ( ethanal) 75 07 0 9.0E 03 I 2.2E 06 I 7.7E 03 calc Acetone ( 2 propanone) 67 64 1 1.0E 01 I 3.1E+ 01 A Acetonitrile ( methyl cyanide) 75 05 8 6.0E 02 I Acetophenone 98 86 2 1.0E 01 I Acrolein 107 02 8 2.0E 02 H 2.0E 05 I Acrylamide 79 06 1 2.0E 04 I 4.5E+ 0 I 1.3E 03 I 4.6E+ 00 calc Acrylic acid ( propenoic acid) 79 10 7 5.0E 01 I 1.0E 03 I Acrylonitrile 107 13 1 1.0E 03 H 5.4E 1 I 2.0E 03 I 6.8E 05 I 2.4E 01 calc Aldrin 309 00 2 3.0E 05 I 1.7E+ 01 I 4.9E 03 I 1.7E+ 01 calc Allyl alcohol 107 18 6 5.0E 03 I Aniline ( benzeneamine) 62 53 3 5.7E 3 I 1.0E 03 I 1.6E 06 C99a 5.6E 03 calc Anthracene 120 12 7 3.0E 01 I Antimony 7440 36 0 4.0E 04 I Arsenic 7440 38 2 3.0E 04 I 1.5E+ 00 I Barium 7440 39 3 7.0E 02 I Benz{ a} anthracene 56 55 3 1.2E+ 00 C99a 1.1E 04 C99a 3.9E 01 calc Benzene 71 43 2 5.5E 02 I 6.0E 02 C00 7.8E 06 I 2.7E 02 calc Benzidine 92 87 5 3.0E 03 I 2.3E+ 02 I 6.7E 02 I 2.3E+ 02 I Benzo{ a} pyrene 50 32 8 7.3E+ 00 I 1.1E 03 C99a 3.9E+ 00 calc Benzo{ b} fluoranthene 205 99 2 1.2E+ 00 C99a 1.1E 04 C99a 3.9E 01 calc Benzyl chloride 100 44 7 1.7E 01 I 4.9E 05 C99a 1.7E 01 calc Benzyl alcohol 100 51 6 3.0E 01 H Table 1. Human Health Benchmarks Used in IWEM ( continued)

Constituent Name CASRN RfD ( mg/ kg d) RfD Ref CSFo ( per mg/ kg d) CSFo Ref RfC ( mg/ m3) RfC Ref URF ( per ug/ m3) URF Ref CSFi ( per mg/ kg d) CSFi Ref Page 6 of 23 Beryllium 7440 41 7 2.0E 03 I Bis( 2 chloroethyl) ether 111 44 4 1.1E+ 00 I 3.3E 04 I 1.2E+ 00 calc Bis( 2 chloroisopropyl) ether 39638 32 9 4.0E 02 I 7.0E 02 H 1.0E 05 H 3.5E 02 calc Bis( 2 ethylhexyl) phthalate 117 81 7 2.0E 02 I 1.4E 02 I 1.0E 02 C99b 2.4E 06 C99a 8.4E 03 calc Bromodichloromethane 75 27 4 2.0E 02 I 6.2E 2 I 1.8E 05 AC 6.2E 02 AC Bromomethane ( methyl bromide) 74 83 9 1.4E 03 I 5.0E 03 I Butadiene, 1,3 106 99 0 2.0E 02 C00 2.8E 04 I 9.8E 01 calc Butanol 71 36 3 1.0E 01 I Butyl benzyl phthalate 85 68 7 2.0E 01 I Butyl 4,6 dinitrophenol, 2 sec ( Dinoseb) 88 85 7 1.0E 03 I Cadmium 7440 43 9 5.0E 04 I Carbon tetrachloride 56 23 5 7.0E 04 I 1.3E 1 I 7.0E 03 SF 1.5E 05 I 5.3E 02 calc Carbon disulfide 75 15 0 1.0E 01 I 7.0E 01 I Chlordane 57 74 9 5.0E 04 I 3.5E 01 I 7.0E 04 I 1.0E 04 I 3.5E 01 calc Chloro 1,3 butadiene, 2 ( Chloroprene) 126 99 8 2.0E 02 H 7.0E 03 H Chloroaniline, p 106 47 8 4.0E 03 I Chlorobenzene 108 90 7 2.0E 02 I 6.0E 02 SF Chlorobenzilate 510 15 6 2.0E 02 I 2.7E 01 H 7.8E 05 H 2.7E 01 calc Chlorodibromomethane 124 48 1 2.0E 02 I 8.4E 2 I 2.4E 05 AC 8.4E 02 AC Chloroethane ( ethyl chloride) 75 00 3 1.0E+ 01 I Chloroform 67 66 3 1.0E 02 I 1.0E 01 A Chloromethane ( methyl chloride) 74 87 3 1.3E 2 H 9.0E 02 I 1.8E 06 H 6.3E 03 calc Chlorophenol, 2 95 57 8 5.0E 03 I 1.4E 03 AC Chloropropene, 3 ( allyl chloride) 107 05 1 1.0E 03 I 6.0E 06 C99a 2.1E 02 calc Chromium ( III) 16065 83 1 1.5E+ 00 I Chromium ( VI) 18540 29 9 3.0E 03 I Chrysene 218 01 9 1.2E 01 C99a 1.1E 05 C99a 3.9E 02 calc Table 1. Human Health Benchmarks Used in IWEM ( continued)

Constituent Name CASRN RfD ( mg/ kg d) RfD Ref CSFo ( per mg/ kg d) CSFo Ref RfC ( mg/ m3) RfC Ref URF ( per ug/ m3) URF Ref CSFi ( per mg/ kg d) CSFi Ref Page 7 of 23 Cobalt 7440 48 4 2.0E 02 SF Copper 7440 50 8 * MCL only Cresol, p 106 44 5 5.0E 03 H 6.0E 01 surr ( C00)

Cresol, o 95 48 7 5.0E 02 I 6.0E 01 surr ( C00)

Cresol, m 108 39 4 5.0E 02 I 6.0E 01 surr ( C00)

Cresols ( total) 1319 77 3 5.0E 02 surr ( I) 6.0E 01 C00 Cumene 98 82 8 1.0E 01 I 4.0E 01 I Cyclohexanol 108 93 0 1.7E 05 solv 2.0E 05 solv Cyclohexanone 108 94 1 5.0E+ 00 I DDD 72 54 8 2.4E 01 I DDE 72 55 9 3.4E 01 I DDT, p, p' 50 29 3 5.0E 04 I 3.4E 01 I 9.7E 05 I 3.4E 01 calc Di n butyl phthalate 84 74 2 1.0E 01 I Di n octyl phthalate 117 84 0 2.0E 02 H Diallate 2303 16 4 6.1E 02 H Dibenz{ a, h} anthracene 53 70 3 7.3E+ 00 TEF 1.2E 03 C99a 4.2E+ 00 calc Dibromo 3 chloropropane, 1,2 96 12 8 1.4E+ 0 H 2.0E 04 I 6.9E 07 H 2.4E 03 calc Dichlorobenzene, 1,2 95 50 1 9.0E 02 I 2.0E 01 H Dichlorobenzene, 1,4 106 46 7 2.4E 2 H 8.0E 01 I 1.1E 05 C99a 3.9E 02 calc Dichlorobenzidine, 3,3' 91 94 1 4.5E 01 I 3.4E 04 C99a 1.2E+ 00 calc Dichlorodifluoromethane ( Freon 12) 75 71 8 2.0E 01 I 2.0E 01 H Dichloroethane, 1,2 107 06 2 9.1E 2 I 2.4E+ 00 A 2.6E 05 I 9.1E 02 calc Dichloroethane, 1,1 75 34 3 1.0E 01 H 5.0E 01 H 1.6E 06 C99a 5.6E 03 calc Dichloroethylene, 1,1 75 35 4 9.0E 03 I 6.0E 1 I 7.0E 02 C00 5.0E 05 I 1.8E 01 calc Dichloroethylene, trans 1,2 156 60 5 2.0E 02 I Dichloroethylene, cis 1,2 156 59 2 1.0E 02 H Dichlorophenol, 2,4 120 83 2 3.0E 03 I Table 1. Human Health Benchmarks Used in IWEM ( continued)

Constituent Name CASRN RfD ( mg/ kg d) RfD Ref CSFo ( per mg/ kg d) CSFo Ref RfC ( mg/ m3) RfC Ref URF ( per ug/ m3) URF Ref CSFi ( per mg/ kg d) CSFi Ref Page 8 of 23 Dichlorophenoxyacetic acid, 2,4 ( 2,4 D) 94 75 7 1.0E 02 I Dichloropropane, 1,2 78 87 5 9.0E 02 A 6.8E 2 H 4.0E 03 I Dichloropropene, trans 1,3 10061 02 6 3.0E 02 I 1.0E 1 I 2.0E 02 surr ( I) 4.0E 06 surr ( I) 1.4E 02 calc Dichloropropene, cis 1,3 10061 01 5 3.0E 02 I 1.0E 1 I 2.0E 02 surr ( I) 4.0E 06 surr ( I) 1.4E 02 calc Dichloropropene, 1,3 ( mixture of isomers) 542 75 6 3.0E 02 I 1.0E 01 I 2.0E 02 I 4.0E 06 I 1.4E 02 calc Dieldrin 60 57 1 5.0E 05 I 1.6E+ 01 I 4.6E 03 I 1.6E+ 01 calc Diethyl phthalate 84 66 2 8.0E 01 I Diethylstilbestrol 56 53 1 4.7E+ 03 H Dimethoate 60 51 5 2.0E 04 I Dimethoxybenzidine, 3,3' 119 90 4 1.4E 02 H Dimethyl phthalate 131 11 3 Dimethyl formamide, N, N ( DMF) 68 12 2 1.0E 01 H 3.0E 02 I Dimethylbenz{ a} anthracene, 7,12 57 97 6 7.1E 02 C99a 2.5E+ 02 calc Dimethylbenzidine, 3,3' 119 93 7 9.2E+ 00 H Dimethylphenol, 2,4 105 67 9 2.0E 02 I Dimethylphenol, 3,4 95 65 8 1.0E 03 I Dinitrobenzene, 1,3 99 65 0 1.0E 04 I Dinitrophenol, 2,4 51 28 5 2.0E 03 I Dinitrotoluene, 2,6 606 20 2 1.0E 03 H 6.8E 01 surr ( I)

Dinitrotoluene, 2,4 121 14 2 2.0E 03 I 6.8E 01 surr ( I) 8.9E 05 C99a 3.1E 01 calc Dioxane, 1,4 123 91 1 1.1E 2 I 3.0E+ 00 C00 7.7E 06 C99a 2.7E 02 calc Diphenylamine 122 39 4 2.5E 02 I Diphenylhydrazine, 1,2 122 66 7 8.0E 1 I 2.2E 04 I 7.7E 01 calc Disulfoton 298 04 4 4.0E 05 I Endosulfan ( Endosulfan I and II, mixture) 115 29 7 6.0E 03 I Endrin 72 20 8 3.0E 04 I Epichlorohydrin 106 89 8 2.0E 03 H 9.9E 3 I 1.0E 03 I 1.2E 06 I 4.2E 03 calc Table 1. Human Health Benchmarks Used in IWEM ( continued)

Constituent Name CASRN RfD ( mg/ kg d) RfD Ref CSFo ( per mg/ kg d) CSFo Ref RfC ( mg/ m3) RfC Ref URF ( per ug/ m3) URF Ref CSFi ( per mg/ kg d) CSFi Ref Page 9 of 23 Epoxybutane, 1,2 106 88 7 2.0E 02 I Ethoxyethanol acetate, 2 111 15 9 3.0E 01 H 3.0E 01 C00 Ethoxyethanol, 2 110 80 5 4.0E 01 H 2.0E 01 I Ethyl acetate 141 78 6 9.0E 01 I Ethyl ether 60 29 7 2.0E 01 I Ethyl methacrylate 97 63 2 9.0E 02 H Ethyl methanesulfonate 62 50 0 2.9E+ 02 RQ Ethylbenzene 100 41 4 1.0E 01 I 1.0E+ 00 I 1.1E 06 SF 3.9E 03 calc Ethylene oxide 75 21 8 1.0E+ 0 H 3.0E 02 C00 1.0E 04 H 3.5E 01 calc Ethylene dibromide ( 1,2 dibromoethane) 106 93 4 8.5E+ 1 I 2.0E 04 H 2.2E 04 I 7.7E 01 calc Ethylene glycol 107 21 1 2.0E+ 00 I 4.0E 01 C00 Ethylene thiourea 96 45 7 8.0E 05 I 1.1E 01 H 1.3E 05 C99a 4.6E 02 calc Fluoranthene 206 44 0 4.0E 02 I Fluorene 86 73 7 4.0E 02 I Fluoride 16984 48 8 6.0E 02 surr ( I)

Formaldehyde 50 00 0 2.0E 01 I 9.8E 03 A 1.3E 05 I 4.6E 02 calc Formic acid 64 18 6 2.0E+ 00 H Furan 110 00 9 1.0E 03 I Furfural 98 01 1 3.0E 03 I 5.0E 02 H HCH, beta 319 85 7 1.8E+ 00 I 5.3E 04 I 1.9E+ 00 calc HCH, gamma ( Lindane) 58 89 9 3.0E 04 I 1.3E+ 00 H 3.1E 04 C99a 1.1E+ 00 calc HCH, alpha 319 84 6 8.0E 03 A 6.3E+ 00 I 1.8E 03 I 6.3E+ 00 calc Heptachlor 76 44 8 5.0E 04 I 4.5E+ 00 I 1.3E 03 I 4.6E+ 00 calc Heptachlor epoxide 1024 57 3 1.3E 05 I 9.1E+ 00 I 2.6E 03 I 9.1E+ 00 calc Hexachloro 1,3 butadiene 87 68 3 3.0E 04 SF 7.8E 2 I 2.2E 05 I 7.7E 02 calc Hexachlorobenzene 118 74 1 8.0E 04 I 1.6E+ 0 I 4.6E 04 I 1.6E+ 00 calc Hexachlorocyclopentadiene 77 47 4 6.0E 03 I 2.0E 04 I Table 1. Human Health Benchmarks Used in IWEM ( continued)

Constituent Name CASRN RfD ( mg/ kg d) RfD Ref CSFo ( per mg/ kg d) CSFo Ref RfC ( mg/ m3) RfC Ref URF ( per ug/ m3) URF Ref CSFi ( per mg/ kg d) CSFi Ref Page 10 of 23 Hexachlorodibenzo p dioxins ( HxCDDs) 34465 46 8 1.5E+ 04 WHO98 3.3E+ 00 WHO98 1.5E+ 04 WHO98 Hexachlorodibenzofurans ( HxCDFs) 55684 94 1 1.5E+ 04 WHO98 3.3E+ 00 WHO98 1.5E+ 04 WHO98 Hexachloroethane 67 72 1 1.0E 03 I 1.4E 2 I 4.0E 06 I 1.4E 02 calc Hexachlorophene 70 30 4 3.0E 04 I Hexane, n 110 54 3 1.1E+ 01 SF 2.0E 01 I Indeno{ 1,2,3 cd} pyrene 193 39 5 1.2E+ 00 C99a 1.1E 04 C99a 3.9E 01 calc Isobutyl alcohol 78 83 1 3.0E 01 I Isophorone 78 59 1 2.0E 01 I 9.5E 4 I 2.0E+ 00 C99b Kepone 143 50 0 5.0E 04 A Lead 7439 92 1 * MCL only Manganese 7439 96 5 4.7E 02 I Mercury 7439 97 6 1.0E 04 surr ( I) 3.0E 04 I Methacrylonitrile 126 98 7 1.0E 04 I 7.0E 04 H Methanol 67 56 1 5.0E 01 I 4.0E+ 00 C00 Methoxychlor 72 43 5 5.0E 03 I Methoxyethanol, 2 109 86 4 1.0E 03 H 2.0E 02 I Methoxyethanol acetate, 2 110 49 6 2.0E 03 H 9.0E 02 C00 Methyl parathion 298 00 0 2.5E 04 I Methyl methacrylate 80 62 6 1.4E+ 00 I 7.0E 01 I Methyl isobutyl ketone 108 10 1 8.0E 02 H 8.0E 02 H Methyl ethyl ketone 78 93 3 6.0E 01 I 1.0E+ 00 I Methyl tert butyl ether ( MTBE) 1634 04 4 3.0E+ 00 I Methylcholanthrene, 3 56 49 5 6.3E 03 C99a 2.2E+ 01 calc Methylene bromide ( dibromomethane) 74 95 3 1.0E 02 H Methylene Chloride ( dichloromethane) 75 09 2 6.0E 02 I 7.5E 3 I 3.0E+ 00 H 4.7E 07 I 1.6E 03 calc Molybdenum 7439 98 7 5.0E 03 I N Nitroso di n butylamine 924 16 3 5.4E+ 0 I 1.6E 03 I 5.6E+ 00 calc Table 1. Human Health Benchmarks Used in IWEM ( continued)

Constituent Name CASRN RfD ( mg/ kg d) RfD Ref CSFo ( per mg/ kg d) CSFo Ref RfC ( mg/ m3) RfC Ref URF ( per ug/ m3) URF Ref CSFi ( per mg/ kg d) CSFi Ref Page 11 of 23 N Nitroso di n propylamine 621 64 7 7.0E+ 00 I 2.0E 03 C99a 7.0E+ 00 calc N Nitrosodiethylamine 55 18 5 1.5E+ 2 I 4.3E 02 I 1.5E+ 02 calc N Nitrosodimethylamine 62 75 9 8.00E 06 SF 5.1E+ 01 I 1.4E 02 I 4.9E+ 01 calc N Nitrosodiphenylamine 86 30 6 2.00E 02 SF 4.9E 03 I 2.6E 06 C99a 9.1E 03 calc N Nitrosomethylethylamine 10595 95 6 2.2E+ 01 I 6.3E 03 C99a 3.7E+ 00 C99a N Nitrosopiperidine 100 75 4 2.7E 03 C99a 9.5E+ 00 calc N Nitrosopyrrolidine 930 55 2 2.1E+ 0 I 6.1E 04 I 2.1E+ 00 calc Naphthalene 91 20 3 2.0E 02 I 3.0E 03 I Nickel 7440 02 0 2.0E 02 I Nitrobenzene 98 95 3 5.0E 04 I 2.0E 03 H Nitropropane, 2 79 46 9 2.0E 02 I 2.7E 03 H 9.5E+ 00 calc Octamethyl pyrophosphoramide 152 16 9 2.0E 03 H Parathion ( ethyl) 56 38 2 6.0E 03 H Pentachlorobenzene 608 93 5 8.0E 04 I Pentachlorodibenzo p dioxins ( PeCDDs) 36088 22 9 1.5E+ 05 WHO98 3.3E+ 01 WHO98 1.5E+ 05 WHO98 Pentachlorodibenzofurans ( PeCDFs) 30402 15 4 7.5E+ 04 WHO98 1.7E+ 01 WHO98 7.5E+ 04 WHO98 Pentachloronitrobenzene ( PCNB) 82 68 8 3.0E 03 I 2.6E 01 H Pentachlorophenol 87 86 5 3.0E 02 I 1.2E 01 I 5.1E 06 C99a 1.8E 02 calc Phenol 108 95 2 6.0E 01 I Phenyl mercuric acetate 62 38 4 8.0E 05 I Phenylenediamine, 1,3 108 45 2 6.0E 03 I Phorate 298 02 2 2.0E 04 H Phthalic anhydride 85 44 9 2.0E+ 00 I 1.2E 01 H Polychlorinated biphenyls ( Aroclors) 1336 36 3 2.0E 05 surr ( I) 4.0E 01 I 1.0E 04 I 4.0E 01 I Pronamide 23950 58 5 7.5E 02 I Propylene oxide ( 1,2 epoxypropane) 75 56 9 2.4E 1 I 3.0E 02 I 3.7E 06 I 1.3E 02 calc Pyrene 129 00 0 3.0E 02 I Table 1. Human Health Benchmarks Used in IWEM ( continued)

Constituent Name CASRN RfD ( mg/ kg d) RfD Ref CSFo ( per mg/ kg d) CSFo Ref RfC ( mg/ m3) RfC Ref URF ( per ug/ m3) URF Ref CSFi ( per mg/ kg d) CSFi Ref Page 12 of 23 Pyridine 110 86 1 1.0E 03 I 7.0E 03 EPA86 Safrole 94 59 7 1.8E 01 RQ Selenium 7782 49 2 5.0E 03 I Silver 7440 22 4 5.0E 03 I Strychnine and salts 57 24 9 3.0E 04 I Styrene 100 42 5 2.0E 01 I 1.0E+ 00 I Tetrachlorobenzene, 1,2,4,5 95 94 3 3.0E 04 I Tetrachlorodibenzo p dioxin ( TCDD),

2,3,7,8 1746 01 6 1.0E 09 A 1.5E+ 5 H 3.3E+ 01 H 1.5E+ 05 H Tetrachlorodibenzo p dioxins ( TCDDs) 41903 57 5 1.5E+ 05 surr ( H) 3.3E+ 01 surr ( H) 1.5E+ 05 surr ( H)

Tetrachlorodibenzofurans ( TCDFs) 55722 27 5 1.5E+ 04 WHO98 3.3E+ 00 WHO98 1.5E+ 04 WHO98 Tetrachloroethane, 1,1,2,2 79 34 5 6.0E 02 SF 2.0E 1 I 5.8E 05 I 2.0E 01 calc Tetrachloroethane, 1,1,1,2 630 20 6 3.0E 02 I 2.6E 2 I 7.4E 06 I 2.6E 02 calc Tetrachloroethylene 127 18 4 1.0E 02 I 5.2E 02 HAD 3.0E 01 A 5.8E 07 HAD 2.0E 03 HAD Tetrachlorophenol, 2,3,4,6 58 90 2 3.0E 02 I Tetraethyl dithiopyrophosphate ( Sulfotep) 3689 24 5 5.0E 04 I Thallium 7440 28 0 8.0E 05 surr ( I)

Thiram ( Thiuram) 137 26 8 5.0E 03 I Toluene 108 88 3 2.0E 01 I 4.0E 01 I Toluenediamine, 2,4 95 80 7 3.2E+ 00 H 1.1E 03 C99a 3.9E+ 00 calc Toluidine, o 95 53 4 2.4E 1 H 6.9E 05 AC 2.4E 01 AC Toluidine, p 106 49 0 1.9E 01 H Toxaphene ( chlorinated camphenes) 8001 35 2 1.1E+ 00 I 3.2E 04 I 1.1E+ 00 calc Tribromomethane ( bromoform) 75 25 2 2.0E 02 I 7.9E 03 I 1.1E 06 I 3.9E 03 calc Trichloro 1,2,2 trifluoroethane, 1,1,2 76 13 1 3.0E+ 01 I 3.0E+ 01 H Trichlorobenzene, 1,2,4 120 82 1 1.0E 02 I 2.0E 01 H Trichloroethane, 1,1,1 71 55 6 2.8E 01 SF 2.2E+ 00 SF Table 1. Human Health Benchmarks Used in IWEM ( continued)

Constituent Name CASRN RfD ( mg/ kg d) RfD Ref CSFo ( per mg/ kg d) CSFo Ref RfC ( mg/ m3) RfC Ref URF ( per ug/ m3) URF Ref CSFi ( per mg/ kg d) CSFi Ref Page 13 of 23 Trichloroethane, 1,1,2 79 00 5 4.0E 03 I 5.7E 02 I 1.6E 05 I 5.6E 02 calc Trichloroethylene ( 1,1,2 trichloroethylene) 79 01 6 1.1E 02 HAD 6.0E 01 C00 1.7E 06 HAD 6.0E 03 HAD Trichlorofluoromethane ( Freon 11) 75 69 4 3.0E 01 I 7.0E 01 H Trichlorophenol, 2,4,5 95 95 4 1.0E 01 I Trichlorophenol, 2,4,6 88 06 2 1.1E 02 I 3.1E 06 I 1.1E 02 calc Trichlorophenoxy) propionic acid, 2( 2,4,5

( Silvex) 93 72 1 8.0E 03 I Trichlorophenoxyacetic acid, 2,4,5 93 76 5 1.0E 02 I Trichloropropane, 1,2,3 96 18 4 6.0E 03 I 7.0E+ 00 H 5.0E 03 SF Triethylamine 121 44 8 7.0E 03 I Trinitrobenzene, sym

( 1,3,5 Trinitrobenzene) 99 35 4 3.0E 02 I Tris( 2,3 dibromopropyl) phosphate 126 72 7 9.8E+ 00 RQ Vanadium 7440 62 2 7.0E 03 H Vinyl acetate 108 05 4 1.0E+ 00 H 2.0E 01 I Vinyl chloride 75 01 4 3.0E 03 I 7.2E 01 I 1.0E 01 I 4.4E 06 I 1.5E 02 calc Xylene, p 106 42 3 2.0E+ 00 surr ( H) 4.0E 01 surr ( A)

Xylene, m 108 38 3 2.0E+ 00 H 4.0E 01 surr ( A)

Xylene, o 95 47 6 2.0E+ 00 H 4.0E 01 surr ( A)

Xylenes ( total) 1330 20 7 2.0E+ 00 I 4.0E 01 A Zinc 7440 66 6 3.0E 01 I Key: CASRN = Chemical Abstract Service registry number. CSFo = oral cancer slope factor.

RfD = reference dose. CSFi = inhalation cancer slope factor.

RfC = reference concentration. URF = unit risk factor. Table 1. Human Health Benchmarks Used in IWEM ( continued)

Page 14 of 23 a Sources:

A = ATSDR MRLs ( ATSDR, 2001) I = IRIS ( U. S. EPA, 2001a)

AC = developed for the Air Characteristic Study ( U. S. EPA, 1999g) RQ = reportable quantity adjustments ( U. S. EPA, 1998d, e, f)

calc = calculated SF = Superfund Risk Issue Paper ( U. S. EPA, 1998a, b; 1999a, b, c, d, e, f;

C99a = CalEPA cancer potency factor ( CalEPA, 1999a) 2000, 2001b, c, d)

C99b = CalEPA chronic REL ( CalEPA, 1999b) solv = 63 FR 64371 0402 ( U. S. EPA, 1998c)