# Toxic Weighting Factor Development in Support of CWA 304(m) Planning Process

Prepared for: 

## U.S. Environmental Protection Agency Engineering and Analysis Division Office of Water 1200 Pennsylvania Avenue, NW Washington, D.C. 20460

Prepared by: 

## Eastern Research Group, Inc. 110 Hartwell Avenue Lexington, MA 02421

June 2006

EPA Contract No. 68-C01-073 Work Assignment 4-17

## CONTENTS Page
SECTION 1 INTRODUCTION
....................................................................................................... 1- 1
1.1 Introduction

.............................................................................................................. ..... 1-1 1.2 Referen ces
................................................................................................................ ..... 1-3
SECTION 2 CURRENT METHODOLOGY
................................................................................. 2-1
2.1 Addition of Hu m a n and Aquatic Health Values

........................................................... 2-1
2.2 Hu m a n Health Criteria

.................................................................................................. 2-2 2.2.1 Effects and Risk Levels

................................................................................ 2-2 2.2.2 Hierarchy of Data Sources

............................................................................ 2-3 2.2.3 Deriving Am bient Water Quality Criteria for the Protection Of Hu m a n Health—1980 Methodol ogy and 2000 Revisions

............................ 2-3 2.2.3.1 BCFs and BAFs

................................................................................ 2-7 2.2.3.2 Relative Source Contribution Factors

.............................................. 2-7 2.2.4 Water Quality Criteria Updates Since 2000

................................................. 2-8
2.3 Chronic Aquatic Life Valu es
...................................................................................... 2-10 2.3.1 National Chronic Freshwater Criteria

......................................................... 2-10 2.3.2 Lowest Reported Measured Maxim u m Allowable Toxicant Concentration, Lowest-Observed-Effect Concentration, or No-Observed-Effect Concentration

........................................................... 2-11 2.3.3 Lowest Chronic or Reproductive Test Concentration

................................ 2-11 2.3.4 Estim ated Chronic Toxicity Concentration from a Measured Acute: Chronic Ratio for a Less Sensitive Species, Quantitative Structure-Activity Relationship Model, or Default Acute: Chronic Ratio of 10:1

...................................................................... 2-12
2.4 Referen ces
................................................................................................................ ... 2-14
SECTION 3 DIOXIN AND CONGENERS
.................................................................................... 3-1
3.1 Slope Factors and TEFs

............................................................................................... 3-1 3.2 BAFs

..................................................................................................................... . 3

- 2 3.3 Referen ces
................................................................................................................ ..... 3-6
SECTION 4 DEVELOP M ENT OF TWF DATABASE
................................................................ 4-1
4.1 Database Overview

....................................................................................................... 4- 1 4.2 Quality Contr o l Reviews

............................................................................................... 4-2 4.3 Referen ces
................................................................................................................ ..... 4-3
SECTION 5 UPDATE TWF DATABASE
..................................................................................... 5-1
5.1 Reference

................................................................................................................ ...... 5-1



### i

### Page

SECTION 6 TWF DEVELOPMENT
............................................................................................. 6-1
6.1 Fall 2004 List of Chem icals

.......................................................................................... 6-1
6.2 Methy l m e rcu r y
............................................................................................................. . 6

- 1 6.2.1 Water Quality Criterion for Methy l m e rcury as a Concentration in Water

........................................................................................................ 6-2 6.2.2 Conversion of RSC fro m a Value to be Subtracted to a Percentage

............. 6-3
6.3 Pol y c y clic Aromatic Co m p ounds (PACs)

..................................................................... 6-4 6.3.1 Background

................................................................................................... 6-4 6.3.2 Hu m a n Health

............................................................................................... 6-4 6.3.3 Aquatic Life Criteria

..................................................................................... 6-6 6.3.4 Remaining Chem icals

................................................................................... 6-7 6.3.5 Summary and Proposed PA C TWFs

............................................................ 6-8
6.4 Nitrogen

................................................................................................................ ...... 6-8 6.4.1 Sodium Nitrite

.............................................................................................. 6-9 6.4.2 Nitrogen C y cle Co m ponents

....................................................................... 6-10 6.4.2

. 1 Ammo nia

......................................................................................... 6-11 6.4.2

. 2 Nitrat e
............................................................................................. 6-12 6.4.2

. 3 Nitrit e
.............................................................................................. 6-12 6.4.2

. 4 Extra polati on to Other Forms of Nitrogen

..................................... 6-12 6.4.2.5 Form s for Which There Is Insufficient Information

........................ 6-13
6.4.3 Nitrogen TWF Summary

............................................................................ 6-13
6.5 Drinking Wat e r Contam inants

.................................................................................... 6-14 6.5.1 Alachlor ESA and Other Acetanilide Pesticide Degradation Products

...................................................................................................... 6-15 6.5.2 Organotins

.................................................................................................. 6-16 6.5.3 Perchlorate

.................................................................................................. 6-16 6.5.4 Triazines and Degradation Products

........................................................... 6-17 6.5.5 Summary

..................................................................................................... 6-18
6.6 Nicotine

................................................................................................................. ... 6-19 6.6.1 Hu m a n Health

............................................................................................. 6-19 6.6.2 Aquatic Health

............................................................................................ 6-20
6.7 Referen ces
................................................................................................................ ... 6-20
ATTACHMENT A TWF DAT A WOR K SHE ETS

.................................................................. A-1

ii

## LIST OF TABLES Page
2-1 Com p arison of 1980 and 2000 Methodologies for Ca lculating Hum a n Health Criteria Based on Slope Factors

............................................................................................................. ......... 2-5
2-2 Com p arison of 1980 and 2000 Methodologies for Ca lculating Hum a n Health Criteria Based on Refere nce Doses

............................................................................................................ ......... 2-6
2-3 Uncertainty F actors and Relative Source Contributi ons
............................................................. 2-9
3-1 Dioxins and Their Equival e ncy Factors

...................................................................................... 3-2
3-2 National Default Values for Lipid Fract ions by Tr ophic Level

.................................................. 3-3
5-1 Com p arison of August and Decem ber 2004 TWF Values Changes Due to Shift to 2000 Methodology

..................................................................................................... .... 5-2
5-2 Changes in TWFs Due to Updates

............................................................................................. . 5

- 3
6-1 Weighted-average National BAF for Methy l m e rcury
................................................................. 6-3
6-2 Conversion of RSC fro m Am ount Subt racted to Percentage

...................................................... 6-3
6-3 Chem icals Included in the EPCRA Section 313 PAC Category

................................................. 6-5
6-4 Changes to Aquatic Life Health Data

........................................................................................ . 6

- 6
6-5 Aquatic Health Data for PAC Chem icals

.................................................................................... 6- 7
6-6 Proposed TW F Summary F o r Va rious Form s of Nitrogen

....................................................... 6-14
6-7 Drinking Wat e r Candidate C ontam inants Needing TWFs

........................................................ 6-15
6-8 Hu m a n and Aquatic Health Data for Triazines and Degradation Products

............................... 6-17
6-9 Drinking Wat e r Candidate C ontam inants Needing TWFs

........................................................ 6-18

iii

### SECTION 1
INTRODUCTION

1.1 INTRODUCTION
In 1981, EPA’ s Office of Water convened a Cost-Effectiveness (C-E) Task Force. Once developed, the Task Force’s m e thodology (called C- E m e thodology ) has been applied to all subsequent rulem a king efforts and has basically withstood the test of tim e, Office of Managem e nt and Budget (OMB) review, and the courts (Ehrensberger and Rico, 1988). All cost-effectiveness calculations are deflated to 1981 dollars—the y ear of the Task Force. The T ask Force selected the Engineering News Record Construction Cost Index (CCI) as the index to be used when deflating the costs to 1981 dollars.

C-E m e thodology is an approach to evaluating a series of pollution control technology trains within an industry , subcategory , or segm e nt of an industry

. In particular, C-E com p ares the increm ental costs of m oving from one technology train option to another with the increm ental rem ovals associated with that change. The procedure identifies “inefficient” options that cost m o re but rem ove less pollutants. When the options are ranked by increasing pollutant re m ovals and plotted against cost, the investigator can visually identify the “elbow in the curve,” where it becom es m u ch m o re expensive to rem ove fewer additional pollutants.
Because each pollutant has its own level of toxi city , it was necessary to develop toxic weighting factors (TWFs). Without such a factor, a pound of tetrachloro-dibenzo- p -dioxin, 2,3,7,8 would have the

sam e “value” (in term s of rem oval) as a pound of copper. TWFs were developed to be protective of both hum an and aquatic life. Section 2 sum m a rizes the TWF m e thodology

.
By converting chem ical discharges to a “toxic-weighted pounds-equivalent” basis, TWFs provide

a m echanism by which discharges containing different m i xtures of chem icals can be com p ared. For effluent guideline developm ent, the com p arison is th e relative efficiency of different technology train options in rem oving chem icals within a given industr y or industry segm e nt. The com p arison is the C-E

m e thodology described in the paragraph above. For planning purposes, such as the 304(m ) process, the discharges from different industries can be com p ared on a toxic-weighted pounds-equivalent basis (TWPE) to identify industries, subcategories, or segm e nts of an industry for which additional pollution controls m i ght be beneficial.

1-1The initial list of pollutants considered in a C-E analy s is focused on priority pollutants. 1 As effluent lim itations guidelines were developed for m o re and m o re industries, the num ber of pollutants for which EPA developed TWFs also increased. At presen t, EPA has developed TWFs for approxim a tely 1,900 chem icals.

The C-E m e thodology was originally intended as a “within-an-industry ” analy tical tool to evaluate different technology train options. EPA r outinely reviewed and updated TWF data at various points in the rulem a king schedule (e.g., option selection), but at any given point in tim e, all pollutants within an industry were com p ared with the sam e set of TWFs. EPA m i ght not have had cause to update a TWF for a pollutant that was detected in wastewater discharges from an industry regulated in the early 1980s if it was not detected in wastewater disch arges from industries regulated after that tim e.
Section 304(b) of the Clean Water Act requires EPA to review effluent guidelines for existing direct dischargers each y ear and to revise the regul ations as appropriate. Section 304(b) also specifies factors that EPA m u st consider when deciding whether to revise an effluent guideline. Section 304(m ) supplem ents the core requirem e nt of Section 304(b) by requiring EPA to publish a plan every two y ears announcing its schedule for this annual review, as we ll as its schedule for any guideline revision that results from the review. EPA has published a final Pl an under Section 304(m ) , every even-num bered y ear since 1990, that describes these activities. For th e 2004 Plan, EPA developed and proposed a draft Strategy for National Clean Water Industrial Regula tions (“National Strategy ”) (EPA, 2002) to outline how EPA would address the factors outlined in Section 304(b). The first factor in the strategy considers the am ount and toxicity of the pollutants rem a ining in an industrial category ’ s discharge. TWFs were used with discharges reported in the Toxics Release Invent ory (TRI) and the Perm it Com p liance Sy stem (PCS) to generate prelim inary ra nkings by industry (EPA, 2004).
With the National Strategy , TWFs underwent a ch ange in role and were used in “industry

- toindustry ” com p arisons. Accordingly EPA decided to develop a TWF database that serves as a selfcontained reference for TWF developm ent. The initial version of the database is the source of the “August 2004” TWF values. EPA developed a list of updates and revisions (Zipf, 2003) that it then incorporated in the database. After revisions and updates, the set of about 1,900 TWFs was called the “Decem ber 2004” TWF values.

1 These pol l u t a nt s are di scussed i n t h e C l ean W a t e r Act (33 USC 1317) Sect i on 307a and C ode of Federal Regulations, Title 40, Part 423, Appendix A.

1-2Section 2 presents EPA’ s m e thodology for deve loping TWFs as well as the revisions and updates to the August 2004 values. Section 3 presents the TWF developm ent for the special case of dioxin and its congeners. The database is described briefly in Section 4 while Section 5 com p ares the August and Decem ber values. As EPA’ s developm ent of effluent lim itations guidelines continues, there is an ongoing need for TWFs for new pollutants or groups of pollu tants. Ongoing efforts are sum m a rized in Section 6.

1.2 REFERENCES Ehrensberger, K., and R. Rico. 1988. Cost-effectiven ess analy s is for effluent guidelines. United States Environm ental Protection Agency , Office of Water Regulations and Standard s, Econom ic Analy s is Branch. May

. EPA. 2004. Notice of availability of 2004 effluent guidelines program plan. Fed. Reg. 69:53,705–53,721. Septem ber 2. EPA. 2002. Draft strategy for national clean wate r industrial regulations. Fed. Reg. 67:71,665–71,169. Novem b er 29. Zipf, L. 2003. Revisions to EAD’s toxic weighti ng factor m e thodology param e ters. Mem o randum to 304(m ) record (EPA docket num ber OW-2003-0074). Decem ber 3.

1-3

### SECTION 2
CURRENT METHODOLOGY

This section provides a brief overview of the m e thodology for calculating TWFs and is drawn from Zipf (2003). The m e thodology was first established in 1981 by EPA’ s Cost-Effectiveness Task Force. One m odification to the m e thodology occurred when the water quality criterion for copper was updated in 1985 (Ehrensberger and Rico, 1988). This is noted in the text below.

The discussion works backward from the TWF (Section 2.1) into its com ponent hum an health and aquatic health com ponents. S ections 2.2 and 2.3 provide additi onal inform ation for the hum an and aquatic health values, respectively , including the pref erence order for data sources. All effluent guidelines prom ulgated under the 1992 Consent Decree used the m e thodology described in this section in the C-E analy ses. These values are discussed in the Developm ent Docum e nt as the “August 2004” TWF values (EPA, 2005a). During the latter part of 2004, EPA incorporated updates and revisions to the

m e thodology and basic data values; these are the “Decem ber 2004” TWF values.

2.1 ADDITION OF HUMAN AND AQUATIC HEALTH VALUES

TWFs are derived from chronic aquatic life crite ria (or toxic effect levels) and hum an health criteria or toxic effect levels established for th e consum ption of fish. For estim ating TWFs for carcinogenic substances, EPA sets the hum an health risk level at 10 -5 (i.e., protective to a level allowing 1 in 100,000 excess lifetim e cancer cases over background). In the TWF m e thod for assessing water-based effects, these toxicity levels of pollutants of concer n are com p ared to a benchm ark value that represents the toxicity level of a specified pollutant. EPA selected copper, a toxic m e tal com m only detected and

rem oved from industrial effluent, as the benchm ark pollutant. EPA had used copper in previous TWF calculations for the cost-effectiveness analy s is of effluent guidelines; although EPA revised the water quality criterion for copper in 1998 (to 9.0 m i crogram s per liter, or μ g/L), the TWF m e thod uses the form er criterion (5.6 μ g/L) to facilitate com p arisons with co st-effectiveness values calculated for other regulations. This was considered valid because all CE m easures are relative (Ehrensberger and Rico, 1988). The form er criterion for copper (5.6 μ g/L) was reported in the 1980 Ambient Water Quality Criteria for Copper docum ent (EPA, 1980).

2-1To calculate TWF values, EPA adds TWFs for aquatic life effects and hum an health effects, where available, for each pollutant of concern. EPA uses chronic effects on aquatic life and hum an health effects from ingesting contam inated organism s (HHOO) as the basis for TWFs. To m a ke the calculation, EPA divides aquatic life and hum an health criteria (o r toxic effect levels) for each pollutant, expressed as a concentration in μ g/L, into the form er copper criterion of 5.6 μ g/L:



### TWF = 56

. + 56

. AQ HHOO

where: TWF = toxic weighting factor AQ = chronic aquatic life value ( μ g/L) HHOO = hum an health value (organism s only ) ( μ g/L)

2.2 HUMAN HEALTH CRITERIA

EPA calculates the hum an health com ponent of a TWF based on consum ption of contam inated organism s. Therefore, EPA envisioned a scenario in which a person would fish or harvest shellfish for

consum ption. The water body in this scenario would not necessarily be a drinking water source.

2.2.1 Effects and Risk Levels
As stated in Section 2.4 of the 2000 Methodology for Deriving Am bient Water Quality Criteria for the Protection of Hum a n Health, “EPA believes that both 10 -6 and 10 -5 m a y be acceptable for the general population....adoption of a 10 -6 or 10 -5 risk level...represents a generally acceptable risk

m a nagem e nt decision” (EPA, 2000).

For chem icals that (1) have both a reference dose (RfD) value for non-carcinogenic effects and a cancer slope factor (CSF) value for carcinogenic effects and (2) draw those RfD and CSF values from sources in the sam e level of the hierarchy (see below) , the hum an health values are calculated using the CSF, which is alway s the m o re stringent value of th e two. When a chem ical has both an RfD and CSF but

2-2these values are from different levels of the hierarchy , the value from the source higher on the hierarchy is used.

2.2.2 Hierarchy of Data Sources
EPA follows a hierarchy of data sources to dete rm ine hum an health values. This hierarchy is based on Section 2.4.6 of the Technical Support Document for Wat er Quality-Based Toxics Control (EPA, 1991), which recom m e nds using the m o st current risk inform ation from EPA’s Integrated Risk Inform ation Sy stem (IRIS) when estim ating hum an health risks. The hierarchy is:

# Calculated hum an health criteria using IRIS (EPA, 2005b) oral RfDs or oral cancer potency CSFs in conjunction with adjusted 3 percent lipid bioconcentration factor (BCF) values derived from Ambient Water Quality Criteria Documents published during the 1980s (EPA, 2005c). Three percent is the m ean lip id content of fish tissue reported in the study from which the average daily fish consum ption rate of 6.5 gram s per day (g/day ) was derived (EPA, 1991).

# Calculated hum an health values using curre nt IRIS RfDs or CSFs and representative unadjusted BCF values for com m on North Am erican species of fish or invertebrates or estim ated BCF values.

# Calculated hum an health values using RfDs or CSFs from EPA’ s Health Effects Assessm ent Sum m a ry Tables (HEAST) or EPA’ s Region III Risk-Based Concentration (RBC) Table (EPA, 2004) used in conjunction with adjusted 3 percent lipid BCF values derived from Ambient Water Quality Criteria Documents

.
# Calculated hum an health criteria using cu rrent RfDs or CSFs from HEAST or EPA’s Region III RBC table and representative BCF values for com m on North Am erican species of fish or invertebrates or estim ated BCF values.

# Criteria from the Ambient Water Quality Criteria Documents

.
# Calculated hum an health values using RfDs or CSFs from data sources other than IRIS, HEAST, or the Region III RBC Table.

2.2.3 Deriving Am bient Water Quality Criteria for the Protection of Hum a n Health— 1980 Methodology and 2000 Revisions
In 2000, EPA published revisions to its “2000 m e thodology ” for deriving am bient water quality criteria for the protection of hum an health (EPA, 2000a and 2000b). Zipf (2003) identified the need to update the TWF calculations to reflect these revisions:

2-3# Change average daily fish consum ption rate from 6.5 gram s to 17.5 gram s/day to adequately protect the general population of fish consum ers.

# Change from bioconcentration factors (BCFs) to bioaccum u lation factors (BAFs). Section 2.2.3.1 discusses how this change is incorporated into the m odel.

# Incorporate a relative source contribution (RSC) to account for non-water sources of exposure. Section 2.2.3.2 discusses how this ch ange is incorporated into the m odel.
Tables 2-1and 2-2 present the equations for calculati ng hum an health criteria with both the 1980 and 2000

m e thodologies. The equation accounts for effect (can cer or non-cancer) and pathway (organism only or water and organism ).
The August 2004 TWF database is based on the 1980 m e thodology . The Decem ber 2004 TWF database is based on the 2000 m e thodology and subse quent water quality criteria updates for specific chem icals (see Section 2.2.4 below).

2-4Table 2-1Comparison of 1980 and 2000 Methodologies for Calculating Human Health Criteria Based on Slope Factors1980 Methodology2000 MethodologyCarcinogenicityProtectionIngestion of Organisms Only()()()HHOOug/LRisk level10q1*70kg1,000 ug/mg0.0065 kg/dayBCFL/kg5=⎛⎝⎜⎜⎞⎠⎟⎟×××−Ingestion of Organisms Only()()()()HHOOug/LRisklevel10q1*70kg1,000 ug/mg0.0175 kg/dayBCFL/kgor BAF(L/kg)5=⎛⎝⎜⎜⎞⎠⎟⎟×××−Ingestion of Water and Organisms()()()()[][]HHWOug/LRisklevel1070kg1,000 ug/mgq1mg/kgday2 L/day+0.0065 kg/dayBCFL/kg5*=××−××−Ingestion of Water and Organisms()()()[][][]HHWOug/LRisklevel10q1*70kg1,000 ug/mg2 L/day+0.0175 kg/dayBCFL/kgor BAF(L/kg)5=⎛⎝⎜⎜⎞⎠⎟⎟×××−where:70 kg=bodyweight2 L/day=dailydrinking water intake0.0065 kg/day=dailyfish intake (1980)0.0175 kg/day=dailyfish intake (2000)RfD=referencedoseq1*=cancer potencyfactor or cancer slope factorRSC=relative source contributionBAF=bioaccumulationfactorBCF=bioconcentrationfactor2-5Table 2-2Comparison of 1980 and 2000 Methodologies for Calculating Human Health Criteria Based on Reference Doses1980 Methodology2000 MethodologyToxicity ProtectionIngestion of Organisms Only()()()HHOOug/LRfDmg/kg/day70 kg1,000 ug/mg0.0065 kg/dayBCFL/kg=×××Ingestion of Organisms Only()()()()HHOOug/LRfDmg/kg/dayRSC70 kg1,000ug/mg0.0175 kg/dayBCFL/kgor BAF(L/kg)=××××Ingestion of Water and Organisms()()()[]HHWOug/LRfDmg/kg/day70kg1,000 ug/mg2L/day0.0065kg/dayBCFL/kg=××+×Ingestion of Water and Organisms()()[][]HHWOug/LRfDmg/kg/day70kg1,000 ug/mg2L/day0.0175kg/dayBCF(L/kg)orBAF(L/kg)=××+×where:70 kg=bodyweight2 L/day=dailydrinking water intake0.0065 kg/day=dailyfish intake (1980)0.0175 kg/day=dailyfish intake (2000)RfD=referencedoseq1*=cancer potencyfactor or cancer slope factorRSC=relative source contributionBAF=bioaccumulationfactorBCF=bioconcentrationfactor2-62.2.3.1 BCFs and BAFs
Bioconcentration is the uptake and retention of a chem ical by an aquatic organism from water only

. Bioaccum u lation is the uptake and retention of a chem ical from all surrounding m e dia (e.g., water, food, and sedim ent). For som e chem icals, e.g., those that are highly persistent and hy drophobic, bioaccum u lation can be far larger than bioconcentr ation. EPA (2000a) recom m e nds shifting from BCFs to BAFs in the calculation of water quality criteria for protection of hum an health.
EPA 2000a outlines separate procedures for deri ving national BAFs depending on the ty pe of chem ical, such as nonionic organic, ionic organic, inorganic, and organom etallic. It also recom m e nds the use of a weighted-average BAF that incorporates four trophic levels, e.g.:

4 

### BAF = 

# ∑ FI i 

### × BAF i i 2 =
where: FI i = fish intake at trophic level I where I = 2, 3, and 4 BAF i = bioaccum u lation factor at trophic level I where I = 2, 3, and 4

The tim e- and resource-intensive nature of es tim ating national BAFs is cited as the reason why EPA did not include BAFs in the hum an health criteria in the National Recom m e nded Water Quality Criteria: 2002 (EPA 2002a). To keep the TWF m odel as fl exible as possible, it is structured to use a BAF value if one exists and a BCF value if one does not.

2.2.3.2 Relative Source Contribution Factors

The TWF m odel is structured to calcula te a hum an health criterion based on the 2000

m e thodology including an RSC factor. The m odel is populated with the RSC values where they are reported in the National Recommended Water Quality Criteria: 2002 (EPA, 2002a) and in Bell (2000). 1 The values reported by Bell are listed in Table 2-3.

1 For t h e purpose of est i m at i ng TW Fs, t h e defaul t val u e for an R S C i s 1.

2-7Table 2-3 Uncertainty Factors and Relative Source Contributions
Uncertainty Factors RSC (%) Chemical Regular Carcinogenic antim ony 1000 — 40 atrazine 100 10 20 barium 3 — NA bery llium 100 10 20 cadm i um 10 — 25 carbofuran 100 — 20 chrom i um 100 — 71 chlorobenzene 1000 — 20 copper 2 — NA cy anide 100 — 20 2,4-D 100 — 20 dalapon 100 — 20 p-dichlorobenzene 1000 10 20 o-dichlorobenzene 1000 10 20 di(2-ethy l hexy l) adipate 100 10 20 1,1-dichloroethy lene 1000 10 20 cis-1,2-dichloroethy lene 3000 — 20 trans-1,2-dichloroethy lene 1000 — 20 dinoseb 1000 — 20 diquat 100 — 20 endrin 100 — 20 ethy lbenzene 1000 — 20 endothall 100 — 20 gly phosate 100 — 20 hexachlorocy clopentadiene 1000 — 20 lindane 1000 10 20

m e thoxy chlor 1000 — 20

m e rcury 1000 — 20
oxam y l 100 — 20 picloram 100 — 20 sim azine 1000 10 20 sty r ene 1000 10 20 2,4,5-TP 100 — 20

2-8Table 2-3 Uncertainty Factors and Relative Source Contributions
Uncertainty Factors RSC (%) Chemical Regular Carcinogenic thallium 1000 — 20 toluene 1000 — 20 1,2,4-trichlorobenzene 1000 — 20 1,1,2-trichloroethane 1000 10 20 1,1,1-trichloroethane 1000 — 20 xy lenes 100 — 20 NA: not appropriate, usually for uncertainty factors and/or RSCs with respect to m a xim u m contam inant level goals and lifetim e health averages set on the basis of hum an data, not anim al research data. Source: Bell, 2000.

2.2.4 Water Quality Criteria Updates Since 2000
EPA updated the TWF m odels with the data presented in National Recommended Water Quality Criteria: 2002 (EPA, 2002a). The values for the com ponents for calculating hum an health criteria were taken from the support docum ent (EPA, 2002b). For som e chem icals, however, EPA (2002a) continues to calculate water quality criteria based on the 1980 m e thodology . The TWF m odel is program ed to select the hum an health com ponent as calculated by the 2000 m e thodology for organism only ingestion. A separate variable was added to the m odel to fl ag when the TWF should use the 1980 m e thodology for calculating the hum an health com ponent. This was done in order to m a ke the TWF m odel consistent with EPA (2002a) unless superceded by a later EPA publication.
On the last day of 2003, EPA published updated national water quality criteria for hum an health for 15 chem icals (EPA, 2003a). 2 EPA incorporated the updated RfD, q1*, RSC, and BCFs into the TWF database for the Decem ber 2004 version.

2 C h l o robenzene; cy ani d e; di chl o robenzene, 1,2; di chl o robenzene, 1,4; di chl o roet hy l e ne, 1,1; d i ch lo ro p r o p e n e , 1 , 3 ; en d r in ; eth y lb en zen e; h e x ach lo ro cyclo p e n t ad ien e ; lin d a n e ; th alliu m ; to lu en e; t r ansdi c hl oroet h y l ene, 1,2; t r i c hl orobenzene, 1,2,4; and vi ny l chl o ri de.

2-92.3 CHRONIC AQUATIC LIFE VALUES
When selecting chronic aquatic toxicity values, EPA uses national water quality criteria, when available. When these criteria are not available, ot her values representative of the chem ical’ s chronic toxicity are used. Sections 2.3.1 through 2.3.4 list va rious data sources for aquatic life values in the sam e order as those sources appear in EPA’ s hierarchy

.

2.3.1 National Chronic Freshwater Quality Criteria
National chronic water quality criteria are the first choice for values because they represent a consideration of a chem ical’s toxicity to wide range of aquatic life and have been published by EPA. The EPA Office of Water describes the derivation of criteri a values in docum ents for specific pollutants (EPA, 2005c). A national chronic water quality criterion is defined as the 4-day average concentration of a toxicant at which a wide range of aquatic organism s should not be unacceptably affected, provided that average is not exceeded m o re than once every 3 y ears, on average.

2.3.2 Lowest Reported Measured Maxim u m Allowable Toxicant Concentration, LowestObserved-Effect Concentration, or No-Observed-Effect Concentration
Chronic aquatic tests m easure the effects of long-term exposure to a chem ical. EPA recom m e nds several 7-day test m e thods (EPA, 1989). Test e ndpoints include percent survival, growth and reproduction.
EPA uses chronic aquatic test data to identify th ree concentration levels of potential significance: the no-observed-effect concentration (NOEC), the low est-observed-effect concentration (LOEC), and the

m a xim u m allowable toxicant concentration (MATC). 3 The NOEC—the highest toxicant concentration to which test organism s have been exposed with no observed adverse effects—can be statistically determ ined using hy pothesis testing or derived fro m the inhibition concentration. This inhibition

3 NOEC , LOEC , and M A TC s are not t h e onl y end poi nt concent r at i ons used by EPA. The W ET (whol e effl uent t oxi ci t y ) program uses t h e IC P (i nduct i v el y coupl ed pl asm a ) m e t hod t o i d ent i f y IC xy (st a t i s t i cal l y or graphically estim ated concentration of a test m a terial which is expected to cause a xy percent i nhi bi t i on i n a prol ogi cal process). EPA al so uses regressi on anal y s es to estim ate ECxy (effective concent r at i on at whi c h xy percent of t h e t e st ed organi sm s show an effect (other than death).

2-10concentration is an estim ate of the toxicant concentr ation that will cause a given percentage reduction in biological m easurem e nt of the test organism s. The LO EC is the lowest toxicant concentration at which a chronic effect on a test organism has been observed. The MATC is the geom etric m ean of the NOEC and LOEC and is m eant to represent the threshold level where chronic effects will begin to occur. MATC values are selected first, followed by LOEC values and then NOEC values for use in calculating TWFs.

2.3.3 Lowest Chronic or Reproductive Test Concentration

For chem icals that do not have chronic aquatic life criteria, MATCs, LOECs, or NOECs, EPA obtains chronic effect concentrations from readily av ailable sources of chronic toxicity test data. The preferred inform ation source is EPA’ s Assessm ent T ools for the Evaluation of Risk (ASTER), which

com b ines the Aquatic Toxicity Inform ation Retr ieval database (AQUIRE), the EPA Environm ental Research Laboratory

– Duluth (ERL-Duluth) fathead m i nnow database, and tables of toxicity test results from water quality criteria docum ents (EPA, 2005d). 4 The ASTER sy stem differentiates between AQUIRE test data that are likely to be of good qua lity and AQUIRE test data that are of unknown quality , according to the following criteria:

# Test pH within the range of 6.5 to 8.5.

# Review code 1 (m ethodology section cites published or well-docum ented procedures; satisfactory control survival; m easured concentr ation; tem p erature, pH, dissolved oxy gen, and hardness are reported) or code 2 (one or m o re of the following m a y occur: control m o rtality not reported; no solvent control when a solvent is used in the test; unm easured concentration; water chem istry variables not reported or incom p lete).

# No use of form ulations or carriers.

# Measured values and flow-through exposure only for tests on fish (no static exposure).

# Measured values only for invertebrates or plants (exposure m a y be static or flowthrough).

Test results from the ERL-Duluth fathead m i nnow database are assum e d to be of good quality . However, test results reported in water quality criteria docum ents are assum e d to be of unknown quality

.

4 Access t o ASTER i s rest ri ct ed as of January 2004 (see ht t p : / / www.epa.gov/ m e d/ Prods_Pubs/ a st er.ht m , downl oaded Sept em ber 15, 2004). ASTER t echni cal support st aff conduct ASTER searches for EPA project s. The public has access to AQUIRE data th rough EPA’s ECOTOX database at ht t p : / / www.epa.gov/ ecot ox/ , b ut t h e EC OTOX dat a base does not screen t h e dat a
.

2-11If a NOEC and a LOEC concentration are available, EPA calculates a MATC value. Otherwise, EPA selects the LOEC or lowest reported concentra tion—from a chronic growth or reproductive test on a North Am erican native fish or invertebrate or from a biologically significant EC 50 test for an algal species (e.g., chlorophy ll production)—from the pool of test da ta likely to be of good quality or, alternatively , from the pool of data of unknown quality . If appropriate test data are not available from ASTER, other prim ary or secondary inform ation sources are consulted.

2.3.4 Estim a ted Chronic Toxicity Concentration from a Measured Acute: Chronic Ratio for a Less Sensitive Species, Quantitative St ructure-Activity Relationship Model, or Default Acute: Chronic Ratio of 10:1

EPA uses estim ated chronic toxicity values when m easured values are unavailable. The first option for estim ating a chronic toxicity concentrati on is to use acute toxicity concentrations and a

m easured acute:chronic ratio (ACR). ACRs are b ased on m easured acute and chronic pollutant concentration values for the sam e sp ecies. The calculated ACR is applied to the acute aquatic toxicity criterion or toxic effect level selected for the pollutant of concern. EPA uses this m e thod when an ACR is available for a species that has a m easured chronic toxi city concentration greater than the acute criterion or the representative acute toxic effect level for th e selected pollutant. These in stances arise when chronic toxicity test data are available for less sensitive speci es only

. The acute aquatic toxic effect level (used if national acute water quality criteria are not available) is ty pically the lowest reported acute aquatic bioassay test concentration (24- to 96-hour lethal c oncentration for 50 percent of the test organism s (an LC 50 ) or an EC 50 (when half the test organism s show a non-lethal effect)) for a North Am erican resident species of fish or invertebrate. As with chronic toxi c effect levels, a test result of good quality is selected ahead of a test result of unknown quality

.
The second option for estim ating a chronic toxicity test concentration is to use ERL-Duluth’s quantitative structure-activity relationship (QSAR) m ode l. QSAR derives statistically based relationships between phy sical-chem i cal properties and biological activity . The QSAR m odel uses m easured toxicity test results for com pounds with sim ilar chem ical st ructures and properties to estim ate MATC values for

com pounds whose chem ical structure and properties are known or m a y be estim ated.
The final option for estim ating a chronic toxicity concentration is to apply an assum e d ACR of 10:1 to the acute aquatic toxic effect concentrati on. The ACR of 10:1 is based on a recom m e ndation in the EPA Office of Water’ s Technical Support Document for Water Quality-based Toxics Control (EPA,

2-121991) for estim ating chronic toxicity when no data are available. The recom m e ndation assum es that the chronic toxicity value is 10 tim es lower than the acute value.

2.4 REFERENCES
EPA. 2005a. 2005 annual screening-level analy s is: supporting the annual review of existing effluent lim itations guidelines and standards and identification of potential new categories for effluent lim itations guidelines and standards. EPA-821-B-05-003. August 2005. http://epa.gov/guide/304m /sla_report.pdf

. Also located in Public Record for the 2006 Effluent Guidelines Program Plan, EPA Docket Num b er OW2004-032-017, see http://www.epa.gov/edoctets

. EPA. 2005b. IRIS database for risk assessm ent. http://www.epa.gov/iris/

. EPA. 2005c. Am bient water quality criteria docum ents for various chem icals published during the 1980s. http://www.epa.gov/waterscience/criteria/1980docs.htm

. EPA. 2005d. ECOTOX data base. http://www.epa.gov/ECOTOX/

. EPA. 2004. Risk-based concentration table. Region 3. October 19. http://www.epa.gov/reg3hwm d /risk/hum an/index.htm

. Downloaded October 27, 2004. (Contains IRIS, HEAST, EPA-NCEA provisional values and EPA peer-reviewed values.) EPA. 2000. Methodology for deriving am bient water quality criteria for the protection of hum an health. EPA-822-B-00-004. October.
EPA. 1999. National recom m e nded water quality cr iteria—correction. EPA-822-Z-99-001. April. EPA. 1991. Technical support docum ent for water quality –based toxics control. EPA-505-2-90-001. March.
EPA. 1989. Short-term m e thods for estim ating the chroni c toxicity of effluent and receiving waters to freshwater organism s. Office of Research and De velopm ent. Cincinnati, Ohio. EPA-600-4-89-001.
EPA. 1980. Am bient water quality criteria for copper. EPA-440-5-80-036. October. http://www.epa.gov/ost/pc/am bientwqc/copper80.pdf

. Downloaded May 17, 2005. Ehrensberger, K., and R. Rico. 1988. Cost-effectiven ess analy s is for effluent guidelines. United States Environm ental Protection Agency , Office of Water Regulations and Standard s, Econom ic Analy s is Branch. May

. Zipf, L. 2003. Revisions to EAD’s toxic weighti ng factor m e thodology oaram e ters. Mem o randum to 304(m ) Record (EPA Docket Num b er OW-2003-0074). Decem ber 3.

2-132-14

### SECTION 3
DIOXIN AND CONGENERS

EPA updated the TWFs for dioxin and its conge ners to be consiste nt with EPA’s ongoing

assessm ent (EPA, 2003b). The revisions incorporate World Health Organization (WHO) Toxicity Equivalency Factors (TEFs) to adjust the cancer slope factors (q1*s) and a derivation of BAFs. These are discussed in detail below.

3.1 SLOPE FACTORS AND TEFS
The Engineering and Analy s is Division (EAD) continues to use the 1985 slope factor for tetrachlorodibenzo- p -dioxin, 2,3,7,8 (TCDD) in calculating TWFs. The 1985 slope factor of TCDD is 160,000 (m g/kg/d) -1 (EPA, 1985). The slope factors of the other congeners are estim ated by m u ltiply ing the slope factor of TCDD by the respective TEF. In accordance with EPA (2003b), EAD used the 1998 WHO TEFs to adjust the 1985 slope factors (Van den Berg et al., 1998). Table 3-1 gives the CAS

num bers, nam es, and TEFs for the 17 congeners.
The revised slope factors are used to cal culate updated hum an health values and the corresponding TWFs. The toxic equivale ncy value is calculated as follows:
= 1.6x10e5 (slope factor) × TEF

For exam ple, for hexachlorodibenzo-p-dioxin,1,2,3,7, 8,9, the toxic equivalency value is calculated as follows: = 1.6x10e5 (slope factor) × 0.1 (TEF)

= 1.6x10e4

3-1Table 3-1 Dioxins and Their Toxic Equivalency Factors

CAS Number Chemical Name Abbreviated Name Toxic Equivalency Factor CDDs 1746-01-6 tetrachlorodibenzo-p-dioxi n, 2,3,7,8 TCDD, 2,3,7,8 1 40321-76-4 pentachlorodibenzo-p-dioxin, 1,2,3,7,8 PeCDD, 1,2,3,7,8 1 39227-28-6 hexachlorodibenzo-p-dioxin, 1, 2,3,4,7,8 HxCDD, 1,2,3,4,7,8 0.1 57653-85-7 hexachlorodibenzo-p-dioxin, 1, 2,3,6,7,8 HxCDD, 1,2,3,6,7,8 0.1 19408-74-3 hexachlorodibenzo-p-dioxin, 1, 2,3,7,8,9 HxCDD, 1,2,3,7,8,9 0.1 35822-46-9 heptachlorodibenzo-p-dioxin, 1,2,3,4,6,7,8 HpCDD, 1,2,3,4,6,7,8 0 .01

3268-87-9 octachlorodibenzo-p-dioxin, 1,2,3,4,6,7,8,9 OCDD, 1,2,3,4,6,7,8,9 0.0001

CDFs 51207-31-9 tetrachlorodibenzofuran , 2,3,7,8 TCDF, 2,3,7,8 0.1 57117-41-6 pentachlorodibenzofuran, 1, 2,3,7,8 PeCDF, 1,2,3,7,8 0.05 57117-31-4 pentachlorodibenzofuran, 2, 3,4,7,8 PeCDF, 2,3,4,7,8 0.5 70648-26-9 hexachlorodibenzofuran, 1,2, 3,4,7,8 HxCDF, 1,2,3,4,7,8 0.1 57117-44-9 hexachlorodibenzofuran, 1,2, 3,6,7,8 HxCDF, 1,2,3,6,7,8 0.1 72918-21-9 hexachlorodibenzofuran, 1,2, 3,7,8,9 HxCDF, 1,2,3,7,8,9 0.1 60851-34-5 hexachlorodibenzofuran, 2,3, 4,6,7,8 HxCDF, 2,3,4,6,7,8 0.1 67562-39-4 heptachlorodibenzofuran, 1,2,3, 4,6,7,8 HpCDF, 1,2,3,4,6,7,8 0.01 55673-89-7 heptachlorodibenzofuran, 1,2,3, 4,7,8,9 HpCDF, 1,2,3,4,7,8,9 0.01 39001-02-0 octachlorodibenzofuran, 1,2,3, 4,6,7,8,9 OCDF, 1,2,3,4,6,7,8,9 0.0001 Source: Van den Berg, et al., 1998.

3.2 BAFs
For dioxin and its congeners, EPA estim ated BA Fs based on the work done for the Great Lakes Water Quality Initiative (EPA, 1995). The BAFs in Ta ble 10 of EPA’s docum ent are lipid norm a lized and freely dissolved based BAFs, also known as “Baselin e BAFs,” and were developed according to the

m e thodology in EPA (2003c). This process of lipid-norm a lization and freely dissolved adjustm e nt essentially “converts” the “site-specific” BAFs (derived from salm onids in the Great Lakes that have

3-2specific lipid and organic carbon content) into va lues that are ready for extrapolation to other conditions—that is, a national BAF.
The first step is to convert the BAFs from EPA (1995) to “Baseline BAFs” using the national defaults for f R (fraction lipid) and f fd (fraction dissolved) and the following equation:

National BAF TL n = [ ( Final Baseline BAF) TL n × (f R ) TL n + 1] × f fd where:

Final Baseline BAF TL n = m ean baseline BAF for trophic level (TL) n (f

R ) TL n = fraction of tissue that is lipid in aquatic organism s at trophic level n f fd = fraction of the total concentration of chem ical in water that is freely dissolved
The national default trophic level–specific lipid fractions (f R ) TL n (where f R = fraction lipid at TL n) are taken from EPA (2003c). These are shown in Table 3-2.

Table 3-2 National Default Values for Lipid Fractions by Trophic Level
Trophic Level National Default Value
2 1.9%
3 2.6%
4 3.0% Source: EPA, 2003c.

The f fd (fraction freely dissolved) is calculated as follows:



### f fd = 1 1 + 

### POC × K OW + 

### DOC × 

### 0

. 08 × 

### K OW

where:

f fd = fraction of the total concentration of chem ical in water that is freely dissolved

3-3POC = concentration of particulate organi c carbon in water (kilogram s of particulate organic carbon per liter of water)
DOC = concentration of dissolved organic carbon in water (kilogram s of dissolved organic carbon per liter of water)
K ow = n -octanol-water partition coefficient

The national default values for POC and DOC are 0.5 m g /L and 2.9 m g /L, respectively

. The derivation of these values is explained in Section 6.3 of EPA (2003c).

For exam ple, the BAF for TCDD, 2,3,7,8 is 9.00x10e+06 for TL 4 (salm onids); and the log K ow is 7.02 (EPA, 1995). Given these two param e ters, we can calculate the national BAF for a given trophic level. The first step is to calculate the fraction of the total concentration of TCDD, 2,3,7,8 that is freely dissolved: 

### f fd = 1 1 + 

### POC × K OW + 

### DOC × 

### 0

. 08 × 

### K OW where:

POC = 5.0 × 10e-7 kg/L (national default values) DOC = 2.9 × 10e-6 kg/L (national default values) Log K ow = 7.02 (that is, K ow = 10 7. 02 , which, in turn, equals 10,471,285)

so: 

### f fd = 1 1 + 

### 5

. 0 x 10 e
− 7 kg / L × 1

. 05 e + 7 + 

### 2

. 9 × 10 e
− 6 kg / L × 0

. 08 × 1

. 05 e + 7

f fd = 1.1541x10e-1
The next step is to insert this value for the freely dissolved fraction of TCDD, 2,3,7,8 into the following equation:

National BAF TL n = [ ( Final Baseline BAF) TL * (f R ) TL n + 1] * f fd where:

Final Baseline BAF TL n = 9.00e+6 for TL 4

3-4(f R ) TL n = 0.03 for TL 4 f fd = 1.1541x10e-1

so:

National BAF TL 4 = [ ( 9.00x10e+06) 4 × (.03) 4 + 1] × 1.1541x10e-1 National BAF TL 4 = 3.1160x10e+4

EPA did not have BAF data for TLs 2 and 3 for dioxin. Therefore, all of the 17.5 gram s/day fish

consum ption was apportioned to TL 4.
Using the equation shown in Table 2-1 for carci nogenicity protection (organism only ) , we obtain:
⎛ ⎜ ⎜ 10 − 5 

# ( ) 160,000 ⎞ ⎟ ⎟ × 70 kg × 1,000 ug / mg HHOO 

## ( ug /L 

## ) = ⎝ ⎠ 0.0175 kg / day × 

## ( 3.1160e +4 × (L / kg) 

## )

or HHOO (ug/L) = 8.02e-9

The toxic weighting factor would be calculated using the following equation:

TW F = 5. 6

− 6 + 5.6

− 9 1. 0e 8.02e or TWF for TCDD 2,3,7,8 is 7.04e+8.

3.3 REFERENCES
Bell, F. 2000. Report on uncertainty factors (UF) and relative source contributions (RSC) for chem icals in the six y ear review. Mem o randum to Cindy Robert s and Joy ce Donahue, EPA, from Frank Bell, NCBA, EPA. Septem ber 26.
EPA. 2003a. National recom m e nded water quality criteria fo r the protection of hum an health. Fed. Reg. 68:75,507–75,515. Decem ber 31.

3-5EPA. 2003b. Exposure and hum an health r eassessm ent of 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD) and related com pounds. EPA-600-P- 00-001Cb. NAS review draft. http://www.epa.gov/NCEA/PCDFs/dioxin/nas-review

. EPA. 2003c. Methodology for deriving am bient water quality criteria for the protection of hum an health technical support docum ent volum e 2: developm ent of national bioaccum u lation factors. EPA-822-R-03­ 030. Decem ber. http://www.epa.gov/waterscience/criteria/hum anhealth/m ethod/tsdvol2.pdf

. EPA. 2002a. National recom m e nded water quality criteria: 2002. EPA-822-R-02-047. Novem b er. EPA. 2002b. National recom m e nded water quality crite ria: 2002. Hum a n health criteria calculation m a trix. EPA-822-R-02-012. Novem b er. EPA. 2000a. Methodology for deriving am bient water quality criteria for the protection of hum an health (2000) Final. EPA-822-B-00-004. October.
EPA. 2000b. Revisions to the m e thodology for deriving am bient water quality criteria for the protection of hum an health (2000); notice. Fed. Reg. 65:66,444–66,482. Novem b er 3. EPA. 1995. Great Lakes Water Quality Initiative t echnical support docum ent for the procedure to determ ine bioaccum u lation factors. EPA-820-B-95-005.
EPA. 1985. Health assessm ent docum ent for poly c hlorinat ed dibenzo-p-dioxins. Office of Health and Environm ental Assessm ent. EPA-600-8-84-814F. ERG. 2004. Fixes to toxic weighting factor (TWF) database. Mem o randum to TWF database project file by Eastern Research Group, Inc. Novem b er 1. Van den Berg, et al., 1998. Toxic equivalency fact ors (TEFs) for PCBs, PCDDs, PCDFs for hum ans and wildlife. Environ. Health Perspect. 106:775-792. Zipf, L. 2003. Revisions to EAD’s toxic weighti ng factor m e thodology param e ters. Mem o randum to 304(m ) Record (EPA Docket Num b er OW-2003-0074). Decem ber 3.

3-6

### SECTION 4
DEVELOPMENT OF TWF DATABASE

4.1 DATABASE OVERVIEW

In May 2004, EPA decided to develop a datab ase to support the transparency , reproducibility , and docum entation of TWF values. The database is in ExcelTM and can be found in the docket. The overall organization of the individual sheets within the file is as follows:

■ Read First: Instructions on using the m odel.

■ Data Dictionary : List of variable nam es, with definitions and sources for the data.

■ TWFs: Master list of TWFs. Hum a n health values based on carcinogens are converted to a 10 -5 risk level, hum an and aquatic health valu es are standardized to the value for copper (5.6 μ g/L), preferred hum an and aquatic hea lth values are identified and added.

■ HH_CALC: Calculated hum an health va lue for carcinogens and non-carcinogens for organism s only and water and organism s. A ll variables are linked to data sheets by Chem ical Abstracts Service (CAS) num ber.

■ AQ_FRESH_ACUTE: The acute aquatic health effect values for freshwater species are based on (e.g., LC 50 , EC 50 , species, and citation). If the data are taken from ASTER, the original reference is included. Separate colu m n s track the source date, last reviewed date, and last update date.

■ AQ_FRESH_CHRONIC: Counterpart to AQ_FRESH_ACUTE for chronic exposures.

■ AQ_SALT_ACUTE: Counterpart to AQ_FRESH_ACUTE for saltwater species.

■ AQ_SALT_CHRONIC: Counterpart to AQ_SALT_ACUTE for chronic exposures.

■ BCF_BAF: Data sheet for BCFs and BAFs, study duration, species, and citation. Separate colum n s track the source date, l ast reviewed date, and last update date.

■ Cancer_Potency _Factor: Cancer potency fact or values—also called cancer slope factors, slope factors, or q 1 *—and citations. Separate colum n s tr ack the source date, last reviewed date, and last update date.

■ Reference Dose: Contains each RfD’ s value, citation, and three colum n s tracking the date of the source, last review, and last update.

■ Relative Source Contribution: A param e ter that adjust the hum an health value for ingestion of aquatic organism s to account for exposure from other sources. Contains

4-1value, citation, and three colum n s tracking the date of the source, last review, and last update.

■ Constants: For exam ple, fish intake for calculating the hum an health criteria.
The purpose of the database is to duplicate the TWFs in use by EPA in a self-contained database whose reader can track the data from the original sources th rough all of the calculations to the final TWF value. As m e ntioned in Section 1, the set of approxim a te ly 1,900 TWF values grew over the course of several decades. The output of the August 2004 database was co m p ared against a m aster list of TWF values and no discrepancies were found. EPA proceeded with its industry analy s is for the 304(m ) process with the August 2004 data while it began an overall review and update of the database according to the needs outlined in Zipf (2003). These updates are discussed in Section 5.

4.2 QUALITY CONTROL REVIEWS

EPA used the structure of the new TWF database to facilitate a series of quality control reviews. These included searching for:

■ Missing references for any of the param e ters.

■ Unknown codes for any of the param e ters.

■ Missing species for any of the aquatic effect values.

■ No adjustm e nt on the carcinogenicity risk values to 10 -5 risk level (i.e., values that should have been adjusted from a 10 -6 risk level to a 10 -5 risk level but were not).

■ Acute:chronic ratios for aquatic health not adjusted to 1991 value of 10.

■ Corrections to references.

■ Pollutants whose TWFs were calculated on either the hum an health or aquatic health data when EPA had data for both param e ters.

■ Pollutants for which no TWF was calculated when EPA had data for at least one of the hum an or aquatic health param e ters. The results of the quality control reviews were sum m a rized in a m e m o to the project files (ERG, 2004).

4-24.3 REFERENCES
ERG. 2004. Fixes to toxic weighting factor (TWF) data. Mem o randum to Ly nn Zipf, EPA, from Eastern Research Group, Inc. Novem b er 1. Zipf, L. 2003. Revisions to EAD’s toxic weighti ng factor m e thodology param e ters. Mem o randum to 304(m ) Record (EPA Docket Num b er OW-2003-0074). Decem ber 3.

4-3

### SECTION 5
UPDATED TWF DATABASE

The updates to the TWF database were com p le ted in Decem ber 2004. EPA then com p ared the August and Decem ber TWF values. Of the approxi m a tely 1,900 pollutants, about 1,450 showed no change between the August and Decem ber databases. Another 372 TWFs registered as showing a change in value due to a shift to the 2000 hum an health m e thodology (“2000 m e thodology ”), but the differences

were so sm all (10e-7 to 10e-19 in value) as to be negligible. Table 5-1 lists TWFs for 26 pollutants for which the change to the 2000 m e thodology resulted in a ch ange of at least 1 percent in the value of the TWF. An additional 54 TWFs change d due to updated data. This group includes dioxin and its congeners; the group is presented in Table 5-2.

When com p aring the August and Decem ber 2004 values, EPA noticed that one pollutant—

m a nganese—no longer had a value. Manganese is anom alous in that EPA (2002) provides a

recom m e nded hum an health value but does not provide any of the underly i ng com ponents used to calculate it. For m a nganese, then, the hum an health va lue is hard-wired instead of being calculated from its com ponent parts.

5.1 REFERENCE

EPA. 2002. National recom m e nded water quality criteri a: 2002. Hum a n Health Criteria Calculation Matrix. EPA-822-R-02-012. Novem b er.

5-1Table 5-1 Comparison of August and December 2004 TWF Values Changes Due to Shift to 2000 Methodology

TWF Values Difference as a Percent Pollutant CAS Number December August Difference Dichloropropene, trans-1,3- 10061026 2.30e-02 2 .33e-02

- 3.97e-04 -1.73% Dichloropropene, cis-1,3- 10061015 2. 30e-02 2 .33e-02

- 3.97e-04 -1.73% Dichloropropene, 1,3- 542756 5. 65e-01 5 .42e-01 6 .57e-03 1.16% Thallium 7440280 1.03e+00 1 .00e+00 2 .53e-02 2.47% Ally l chloride 107051 3.35e-03 2 .91e-03 1 .16e-04 3.47% Chlorine 7782505 5.09e-01 4 .87e-01 2 .21e-02 4.35% Tribrom o m e thane 75252 4.57e-03 1 .75e-03 2 .10e-04 4.59% Trichloroethene 79016 1.91e-02 6 .44e-03 8 .82e-04 4.62% Sim azine 122349 6.42e-01 5 .61e-01 3 .01e-02 4.68% BHC, gam m a -/lindane 58899 7.03e +01 4 .69e+01 8 .56e+00 12.18% Dinitrotoluene, 2,4- 121142 4. 45e-01 2 .81e-01 6 .05e-02 13.57% Arsenic 7440382 4.04e+00 3 .47e+00 5 .72e-01 14.15% Nitrosopy rrolidine, – 930552 1.62e-02 3 .28e-03 2 .73e-03 16.88% Chry sene 218019 3.10e+01 2 .10e+00 9 .63e+00 31.07% Indeno(1,2,3-cd)py r ene 193395 3.07e+01 1 .14e+00 1 .02e+01 33.43% Tetrachloroethene 127184 2.34e-01 1 .26e-02 8 .12e-02 34.72% Atrazine 1912249 2.31e+00 9 .44e-02 8 .23e-01 35.60% Pentachloronitrobenzene/ Quintozene 82688 3.85e+01 7 .41e-01 1 .39e+01 36.13%
Alachlor/Lasso 15972608 1.78e+00 1 .57e-02 6 .49e-01 36.52% Aldrin 309002 1.11e+04 5 .02e+01 4 .10e+03 36.84% Parachlorom e tacresol 59507 1.33e+00 4 .33e-03 4 .93e-01 37.02% Chlorobenzilate 510156 7.92e+0 1 1 .56e-01 2 .93e+01 37.03% Trichloropropane, 1,2,3- 96184 5. 26e+00 1 .96e-03 1 .95e+00 37.11% Hy drofluoric acid 7664393 5.60e-06 0 .00e+00 2 .08e-06 37.14% Aflatoxins 4402682 1.79e+04 0 .00e+00 6 .64e+03 37.14% Azinphos m e thy l/ Guthion, m e thy l 86500 5.61e+01 2 .80e+01 2 .80e+01 49.93%
Cadm ium 7440439 2.31e+01 2 .61e+00 1 .99e+01 85.89% Ethoprophos 13194484 8.89e+01 3 .81e-01 8 .85e+01 99.57% Source: EPA estim ates.

5-2Table 5-2Changes in TWFs Due to UpdatesPollutantCAS NumberTWFReasons for DifferencesDecemberAugustTetrachlorodibenzo-p-dioxin, 2,3,7,8-17460167.04E+084.22E+08Dioxin congener: change fromBCFs to BAFsPentachlorodibenzo-p-dioxin, 1,2,3,7,8-403217646.93E+082.15E+08Dioxin congener: change fromBCFs to BAFsHexachlorodibenzo-p-dioxin, 1,2,3,7,8,9­194087431.06E+074.31E+07Dioxin congener: change fromBCFs to BAFsHexachlorodibenzo-p-dioxin, 1,2,3,4,7,8­392272862.35E+074.31E+07Dioxin congener: change fromBCFs to BAFsHexachlorodibenzo-p-dioxin, 1,2,3,6,7,8­576538579.56E+064.18E+07Dioxin congener: change fromBCFs to BAFsPentachlorodibenzofuran, 2,3,4,7,8-571173145.57E+083.29E+07Dioxin congener: change fromBCFs to BAFsTetrachlorodibenzofuran, 2,3,7,8-512073194.38E+076.70E+06Dioxin congener: change fromBCFs to BAFsHexachlorodibenzofuran, 1,2,3,7,8,9-729182194.73E+076.67E+06Dioxin congener: change fromBCFs to BAFsHexachlorodibenzofuran, 1,2,3,6,7,8-571174491.41E+076.67E+06Dioxin congener: change fromBCFs to BAFsHexachlorodibenzofuran, 1,2,3,4,7,8-706482695.76E+066.66E+06Dioxin congener: change fromBCFs to BAFsHexachlorodibenzofuran, 2,3,4,6,7,8-608513455.12E+076.66E+06Dioxin congener: change fromBCFs to BAFsHeptachlorodibenzo-p-dioxin,1,2,3,4,6,7,8-358224694.11E+054.18E+06Dioxin congener: change fromBCFs to BAFsPentachlorodibenzofuran, 1,2,3,7,8-571174167.63E+063.29E+06Dioxin congener: change fromBCFs to BAFsHeptachlorodibenzofuran, 1,2,3,4,7,8,9-556738973.03E+066.67E+05Dioxin congener: change fromBCFs to BAFsHeptachlorodibenzofuran, 1,2,3,4,6,7,8-675623948.58E+046.66E+05Dioxin congener: change fromBCFs to BAFsOctachlorodibenzo-p-dioxin32688796.59E+034.24E+05Dioxin congener: change fromBCFs to BAFsOctachlorodibenzofuran390010202.02E+036.74E+04Dioxin congener: change fromBCFs to BAFsDieldrin605711.06E+045.67E+04BCF changed; new value taken fromEPA, 2002Benzo(a)pyrene503281.01E+024.28E+03BCF changed; new value taken fromEPA, 2002Dibenzo(a,h)anthracene537033.07E+011.69E+03BCF changed; new value taken fromEPA, 2002Benzo(b)fluoranthene2059923.07E+014.21E+02BCF changed; new value taken fromEPA, 2002Benzo(a)anthracene565533.63E+011.81E+02BCF changed; new value taken fromEPA, 2002Mercury74399761.17E+021.17E+02BCF changed; new value taken fromEPA, 2002Benzo(k)fluoranthene2070893.07E+014.21E+01BCF changed; new value taken fromEPA, 2002Nitrosodi-n-butylamine, –9241632.56E+004.77E+00BCF changed; new value taken fromEPA, 20025-3Table 5-2Changes in TWFs Due to UpdatesPollutantCAS NumberTWFReasons for DifferencesDecemberAugustNitrosodi-n-propylamine, –6216471.11E+002.29E+00BCF changed; new value taken fromEPA, 2002Aniline625336.86E-031.41E+00BCF changed; new value taken fromASTERPentachlorobenzene6089353.77E+002.26E+00BCF changed; new value taken fromEPA, 2002Vanadium74406223.50E-026.22E-01Aquatic health value changed; new values taken fromASTERDibromochloromethane1244814.45E-021.27E-01BCF changed; new value taken fromEPA, 2002Trichlorophenol, 2,4,6-880624.98E-014.44E-01BCF changed; new value taken fromEPA, 2002Bromodichloromethane752743.29E-027.42E-02BCF changed; new value taken fromEPA, 2002Trichlorobenzene, 1,2,4-1208212.55E-028.21E-02BCF changed; new value taken fromEPA, 2002Manganese74399651.44E-027.04E-02TWF database will be updated to include human healthvaluesChloroethene750148.55E-021.16E-01q1* changed; new value taken fromIRISPyrene1290009.32E-021.11E-01BCF changed; new value taken fromEPA, 2002Trichlorophenol, 2,4,5-959541.78E-022.62E-02BCF changed; new value taken fromEPA, 2002Ethylenethiourea964571.56E-016.71E-02q1* changed, see memo“Fixes to Toxic WeightingFactor (TWF) Data” fromMaureen Kaplan, ERG, toLynn Zipf, EPA, dated November 1, 2004Beryllium74404171.06E+001.06E+00BCF changed; new value taken fromEPA, 2002Nitrophenol, 4-1000274.89E-039.44E-03BCF changed; new value taken fromEPA, 2002Fluorene867377.01E-017.04E-01BCF changed; new value taken fromEPA, 2002Chloronaphthalene, 2-915872.16E-022.23E-02BCF changed; new value taken fromEPA, 2002Anthracene1201272.55E+002.55E+00BCF changed; new value taken fromEPA, 2002Ammonia as N76644171.35E-031.83E-03Fresh acute value changed; value taken from1999update of ambient water qualityfor ammonia5-4Table 5-2Changes in TWFs Due to UpdatesPollutantCAS NumberTWFReasons for DifferencesDecemberAugustDichloroethene, 1,2-5405901.46E-031.27E-03Oral reference dose changed; see memo“Fixes to ToxicWeighting Factor (TWF) Data” fromMaureen Kaplan,ERG, to Lynn Zipf, EPA, dated November 1, 2004Bromomethane748395.98E-025.77E-02BCF changed; new value taken fromEPA, 2002Dichloropropane, 1,2-788753.94E-021.55E-02BCF changed; new value taken fromEPA, 2002Hexachlorobutadiene876836.33E-016.14E-01BCF changed; new value taken fromEPA, 2002Benzene714323.17E-021.84E-02BCF changed; new value taken fromEPA, 2002Dimethylphenol, 2,4-1056799.41E-035.29E-03BCF changed; new value taken fromEPA, 2002Dichloromethane750921.01E-034.23E-04BCF changed; new value taken fromEPA, 2002Dinitrophenol, 2,4-512858.14E-037.48E-03BCF changed; new value taken fromEPA, 2002Dichloroethene, trans-1,2-1566059.20E-059.25E-05BCF changed; new value taken fromEPA, 2002Bis(2-chloroisopropyl) ether1086012.54E-021.26E-03BCF changed; new value taken fromEPA, 2002Source: EPA estimates.5-5

### SECTION 6
TWF DEVELOPMENT

As EPA continues to study different industries and their discharges as reported to TRI and PCS, there is a periodic need to review, update, and/or develop TWFs for specific chem icals or groups of chem icals. Appendix A contains the data sheets de veloped for sum m a rizing the inform ation available. After EPA’ s internal review, these will be incorporated in the next release of the TWF database. Section 6.1 discusses updates requested in the fall of 2004. Sections 6.2 through 6.5 provide background inform ation on the developm ent of TWFs for m e th y l m e rcury , poly c y c lic arom atic com pounds (PACs), nitrogen, and the second list of drinking water c ontam inants published by EPA on February 24, 2005 (EPA, 2005a).

6.1 FALL 2004 LIST OF CHEMICALS

In October 2004, EPA decided to review , update, and/or develop TWFs for:



### ■ Hydrogen fluoride, CAS 7664393 ■ Chlorine dioxide, CAS 10049044 ■ 1,3-phenylenediam i ne, CAS 108452 ■ Benzo(a)pyrene, CAS 50328 ■ Aniline, CAS 62533 ■ Vanadium , CAS 7440622 The worksheets are shown in Appendices A-2 through A-7.

6.2 METHYLMERCURY
EPA (2002a) presents a hum an health water quality criterion for m e thy l m e rcury expressed as a fish and shellfish tissue concentration. The criteri a for all other contam inants are expressed as water colum n concentrations. EPA also presented the RSC for m e thy l m e rcury as an am ount subtracted from the RfD, rather than as a percentage as is done with the other contam inants.

6-1For the TWF database, however, EPA needs to convert the water quality criterion from a
m e thy l m e rcury concentration in fish tissue to a m e thy l m e rcury concentration in water. EPA also needs to convert the RSC to a percentage for use in the TW F database. TWFs are used in the 304 (m ) process as part of a screening tool. The level of evidence n ecessary to support a screening use is not as stringent as that needed to establish water quality criteria. Thus , EPA considered these conve rsions appropriate to support this task. The first conversion is discussed in Section 6.2.1 while the second is presented in Section 6.2.2. The data sheets for m e rcury and m e thy l m e rcury are located in Appendix A-8 and A-9, respectively

. The m e thy l m e rcury TWF will be applied only to m e thy l m e rcury discharges.

6.2.1 Water Quality Criterion for Methylmercury as a Concentration in Water

In a Federal Register notice (EPA, 2001a), EPA provided three approaches to relate the

m e thy l m e rcury fish tissue water quality criterion to a concentration of m e thy l m e rcury in the water colum n . The first approach is to collect site-speci fic BAFs based on water and fish collected in the waterbody of concern. This appro ach is not appropriate for a nationa l-level analy s is. The second approach is to use a bioaccum u lation m odel with site-specific param e ters. Again, the site-specific nature of the approach is not appropriate fo r a national-level analy s is.

The third approach is to use em pirically derived draft BAFs. 1 These are national estim ates. The Federal Register notice’s data for fish intake (FI) by trophic level and BAF by trophic level were used to create a weighted-average national BAF for m e thy l m e rcury for the purpose of estim ating a TWF for the 304(m ) process. Table 6-1 reproduces the calculations. For each trophic level, the product of the BAF and the FI are used. For exam ple, for trophic level 2, the product of 1.6x10e5BAF and .0038 (kg/day ) FI is 608. The calculation is repeated for trophic levels 3 and 4. The final colum n in Table 1 is the sum of the FIs (0.0175 kg/day ) and the product of the BAFs (21,438). Dividing 21,438 by the total FI (0.0175) estim ates the weighted-average BAF value of 1.225029x10e6.

1 Fi nal m e t h y l m e rcury B A Fs were not found i n t h e Federal Register for 2001 t h rough M a y 2006.

6-2Table 6-1 Weighted-Average National BAF for Methylmercury

Parameter Trophic Level Sum 2 3 4 Bioaccum u lation factor 1.60e+05 6 .80e+05 2 .70e+06 Fish intake (kg/day ) 3.80e -03 8 .00e-03 5 .70e-03 1.75e-02
Product: BAF(trophic level) × FI(trophic le vel) 6.08e+02 5 .44e+03 1 .54e+04 2.14e+04
Weighted average BAF 1.23e+06 Source: EPA, 2001.

6.2.2 Conversion of RSC from a Value to be Subtracted to a Percentage
EPA (2001a) presents the RSC as an am ount to be subtracted rather than a percentage. The equations in the TWF m odel assum e the RSC is a percentage. Table 6-2 shows the conversion calculations. The RfD for m e thy l m e rcury is 0.1 μ g/kg/day (66 FR 1353), or 0.0001 m g /kg/day

. The RSC in the subtraction approach is 2.7 × 10 -5 , or 0.000027 m g /kg/day (66 FR 1354). The difference between the RfD and the RSC, i.e., the am ount to be m u ltip lied by body weight in the water quality criterion calculations, is 7.25 × 10 -5 , or 0.0000725. Dividing 0.0000725 by 0.0001 equals 0.725. The equivalent value for RSC is 73 percent.

Table 6-2 Conversion of RSC from Amount Subtracted to Percentage

Parameter Value RfD (m g/kg BW-day ) 0.0001000 RSC (m g/kg BW-day ) 0.0000275

Difference 0.0000725
(RfD-RSC)/RfD = RSC as a percentage of RfD 0.7250000 Source: EPA estim ates, see discussion in Section 6.2.2.

6-36.3 POLYCYCLIC AROMATIC COMPOUNDS

6.3.1 Background

Table 6-3 lists the 21 chem icals considered to be PACs, based on the Em ergency Planning and Com m unity Right-To-Know Act guidance as of August 2001 (EPA, 2001b). Most of these com pounds are the product of incom p lete com bustion or are from fossil fuels. Two of these chem icals— dim e thy l benz(a)anthracene, 7, 12 and m e thy l cholanth rene, 3—have been produced in sm all quantities as research chem icals. They are listed in EPA (2001b) as form ed during com bustion. Understandably , no hum an health or aquatic life data are available for these two chem icals and they are excluded from further discussion in this m e m o randum

.

Section 6.3.2 reviews the chem icals for which EPA has already developed hum an health water quality criteria using the 2000 m e thodology . Section 6. 3.3 sum m a rizes the availability of aquatic life values for the PACs listed in Section 6.3.2. Secti on 6.3.4 discusses the hum an and aquatic health data available for the rem a ining chem icals. Section 6.3.5 sum m a rizes the findings and EPA’ s decision on a PAC TWF. Worksheets for each chem ical are located in Appendix A-5 and A-10 through A-27.

6.3.2 Hum a n Health
EPA (2002a) published water quality criteria for:

# Benzo(a)anthracene # Benzo(a)phenanthrene (chry sene) # Benzo(a)py rene # Benzo(b)fluoranthene # Benzo(k)fluoranthene # Benzo(j,k)fluorene (fluoranthene) # Dibenzo(a,h)anthracene # Indeno(1,2,3-cd)py r ene EPA (2002b) also noted that the IRIS value for be nzo(b)fluoranthene (CAS 205992) was used to derive the value presented for benzo(a)anthracene, benzo( a)phenanthrene (chry sene), benzo(k)fluoranthene,

6-4Table 6-3 Chemicals Included in the EPCRA Section 313 PAC Category

Chemical Name CAS Number Benzo(a)anthracene 56553 Benzo(a)phenanthrene (chry sene) 218019 Benzo(a)py rene 50328 Benzo(b)fluoranthene 205992 Benzo(j)fluoranthene 205823 Benzo(k)fluoranthene 207089 Benzo(j,k)fluorene (fluoranthene) 206440 Benzo(r,s,t)pentaphene 189559 Dibenz(a,h)acridine 226368 Dibenz(a,j)acridine 224420 Dibenzo(a,h)anthracene 53703 Dibenzo(a,e)fluoranthene 5385751 Dibenzo(a,e)py rene 192654 Dibenzo(a,h)py rene 189640 Dibenzo(a,l)py rene 191300 7H-dibenzo(c,g)carbazole 194592 7,12-dim e thy l benz(a)anthracene 57976 Indeno(1,2,3-cd)py r ene 193395
3-m e thy l cholanthrene 56495
5-m e thy l chry sene 3697243 1-nitropy rene 5522430 Source: EPA, 2001b.

6-5dibenzo(a,h)anthracene, and indeno(1,2,3-cd)py r ene. As such, data are truly only available for three chem icals:

# Benzo(a)py rene # Benzo(b)fluoranthene # Benzo(j,k)fluorene (fluoranthene)

6.3.3 Aquatic Life Criteria
EPA (2002a) did not publish corr esponding aquatic life criteria for the eight PACs listed in Section 6.3.2. ASTER data were reviewed in order to identify appropriate studies and values for deriving aquatic life endpoints. ASTER som e tim es reports st udies in two separate sections—the first section includes studies that pass ASTER’ s filter for data of the highest quality and the second section includes studies that do not pass the filter for data quality but are included in the AQUIRE (now ECOTOX) database. A researcher with access only to ECOTOX w ould not have identified better data sources.
Where possible, data that passed the ASTER filte r were used. In addition, data were not used— even if they passed the filter—if the citation w as a personal com m unication. With these two criteria, higher concentrations than those cited in the earlier TWF data were identified. That is, both citations appear in ECOTOX, but the study that ASTER iden tified as being of higher quality was used. Tables 6-4 and 6-5 sum m a rize these changes.

Table 6-4 Changes to Aquatic Life Health Effect Levels

Chemical Aquatic Life Category Values ( μ g/L) Old New Benzo(a)anthracene Fresh-acute 10 1,599 Benzo(a)anthracene Fresh-chronic 1 160 Benzo(a)phenanthrene chry sene Fresh-acute 592 1,599 Benzo(a)phenanthrene chry sene Fresh-chronic 16 160 Benzo(j,k)fluorene (fluoranthene) Fresh-chronic 7.1 4.5 Dibenzo(a,h)anthracene Fresh-acute NA 496 Dibenzo(a,h)anthracene Fresh-chronic NA 50 Source: ASTER, 2004.

6-6Table 6-5 Aquatic Health Data for PAC Chemicals

Fresh Salt
Chemical Chronic Acute Chronic Acute Benzo(a)anthracene 160 1,599 7.5 75 Benzo(a)phenanthrene (chry sene) 160 1,599 Benzo(a)py rene 0.08 5 100 1,000 Benzo(j,k)fluorene (fluoranthene) 4.5 45 7H-dibenzo(c,g)carbazole 185 1,852 1-nitropy rene 215 2,149 Dibenzo(a,h)anthracene 496 496 5 50 Source: ASTER, 2004.

6.3.4 Rem a ining Chem icals

The rem a ining PACS for which no wate r quality criteria were available are:

# Benzo(j)fluoranthene # Benzo(r,s,t)pentaphene # Dibenz(a,h)acridine # Dibenz(a,j)acridine # Dibenzo(a,e)fluoranthene # Dibenzo(a,e)py rene # Dibenzo(a,h)py rene # Dibenzo(a,l)py rene # 7H-dibenzo(c,g)carbazole # 5-m e thy l chry sene # 1-nitropy rene
No hum an health criteria were found for these 11 chem icals in IRIS, the EPA Region 3 RBC Table, ATSDR toxicological profiles, the EPA 2000 Water Quality Standards, or the EPA 1995 Final Water Quality Guidance for the Great Lakes Sy stem . ASTER data were exam ined for these chem icals, and only data for 7H-dibenzo(c,g)carbazole were found.

6-76.3.5 Sum m a ry and Proposed PAC TWF
For the purpose of screening industries in the 304 (m ) process, EPA has chosen to use the TWF for benzo(a)py rene , which is the highest TWF (100.66) for PACs, because it represents the worst case scenario. In m o re detailed studies for an industry , EPA anticipates separating the PAC discharge into its

com ponents and using the chem ical-specific TWFs.

6.4 NITROGEN
EPA decided to perform a com p rehensive review of aquatic and hum an health data for nitrogen in various form s in order to provide a consistent and docum ented basis for the proposed TWFs. TRI and PCS report discharges for:

# Sodium nitrite # Am m onia # Nitrogen, total (as N) # Nitrogen, Kjeldahl total (as N) # Nitrogen oxides (as N) # Nitrogen, organic total (as N) # Nitrogen, nitrite total (as N) # Nitrogen, inorganic total # Nitrogen, Kjeldahl total (TKN) # Nitrite nitrogen, dissolved (as N) # Nitrogen, nitrite total (as NO 2 ) # Nitrogen (as NO 3 ) sludge solid
For nitrogen, the sensitive population is an infa nt or sm all child and the m a jor pathway is drinking water. Nitrite reacts with the ferrous iron in hem oglobin to form m e them oglobin with iron in the ferric valence state. Ferric iron is unable to transport oxy gen, leading to shortness of breath, skin turning blue, and oxy gen deprivation in the brain. Although hum ans convert ingested nitrate into nitrite in the gut, the am ount converted depends on several factors. The pH of the gut is norm a lly higher in infants than in older children and adults, and the higher pH enhances nitrate-to-nitrite conversion. In addition, fetal hem oglobin is oxidized m o re readily by nitrite to m e them oglobin, m a king infants and children the sensitive subpopulation (ATDSR, 2001; IRIS, 2004, 2005a).

6-8The hum an health com ponent of a TWF , however, is based on the exposure of an adult via organism only (not drinking water and organism ; see Table 2-1 and Section 2.2). As IRIS (2005a) notes, nitrate is a norm a l com ponent of the hum an diet. In addition, there is no oral RfD for am m onia reported in IRIS (IRIS, 2005b). For these reasons, no human health component is calculated for the various form s of nitrogen. The TWFs are based on aquatic health only

.

6.4.1 Sodium Nitrite

Sodium nitrite is not included in the form s of organic nitrogen listed in APHA et al., 1995. It should not be surprising, then, that its TWF m i ght differ substantially from those for com ponents of the nitrogen cy cle. Sodium nitrite was added to the list of chem icals reported in TRI in 1994 under the Em ergency Planning and Com m unity Right-to-K now Act (EPCRA) section 313(d)(2)(B) based on chronic hem a tological and developm ental toxic ity data from m ouse and rat studies (EPA, 1994).
The ASTER report for sodium nitrite CAS 7632-00- 0 references m o re than 120 studies. Only the studies that passed the ASTER filter were considered for the TWFs. The m e dian values for the reported acute LC 50 values are:

# Rainbow trout, 96-hr LC 50 : 150 μ g/L # Cutthroat trout, 96-hr LC 50 : 560 μ g/L # Fathead m i nnow, 96-hr LC 50 : 2,990 μ g/L

The m e dian values for the reported chronic effects are:

# Channel catfish, 31-day exposure, growth: 1,620 μ g/L # Channel catfish, 31-day exposure, m o rtality : 1,250 μ g/L
There is a range of sensitivity in the species ex am ined. Channel catfish ar e far less sensitive than rainbow trout; the chronic values for catfish are about 10 tim es higher than the acute value for rainbow trout. The sensitivity of salm onids is apparent for am m onia as well as sodium nitrite; see EPA (1999a) Figure 8, where the graphs for salm onids have a m a xim u m value of 200 m g N/L, while the m a xim u m values for other species range from 400 m g N/L to 2,000 m g N/L for catfish. See also EPA (1999a), Figure 11 and pages 40–41, concerning the sensitivity of salm onids to pollutants.

6-9Within the acute data, a study of fathead m i nnows reported a 96-hour LC 50 acute value of 2,990 μ g/L, a factor of 20 tim es higher than the 96-hour LC 50 acute value reported for rainbow trout of 150 μ g/L.
For the purpose of a national-level screening tool , EPA considers it appropriate to base a TWF on a sensitive species. Further investigation into the ty pes of water bodies and the aquatic fauna in them would occur if an industry is selected for additional study . EPA uses the lowest 96-hour LC 50 acute value for rainbow trout and reduces it by an order of m a gn itude to estim ate the chronic value, that is 15 μ g/L.

Sodium nitrite is reported to TRI as pounds of sodi um nitrite released. The aquatic health data are reported in μ g/L of sodium nitrite (not nitrogen). The disch arges reported in TRI and the TWF for sodium nitrite are on the sam e basis.
Finally , the sodium nitrite TWF is applied to s odium nitrite in the actual discharge. That is, TRI conventions m i ght require reporting certain releases as sodium nitrite when, based on chem ical and engineering reasons and/or m onitoring data, the actual discharge contains another form of nitrogen. EPA, under these circum stances, would apply the TWF for the appropriate form of nitrogen in the release.

6.4.2 Nitrogen Cycle Com p onents
This discussion is based prim arily on the inform ation in Standard M e thods (APHA et al., 1995). In order of increasing oxidation state, the form s of nitrogen in the cy cle are:

# Organic nitrogen (organically bound nitrogen in the tri-negative oxidative state—includes urea, nucleic acids, peptides, and proteins) # Am m onia # Nitrite # Nitrate

Som e analy ses are reported in term s of “Kjeldahl nitrogen”or TKN. TKN refers to am m onia plus organic nitrogen identified in a single analy s is. It is nam e d after J. Kjeldahl, who invented the analy tic

m e thods. The analy s is results do not m easure nitrogen in the form of nitrate, nitrite, nitrile, nitroso, onim e , azide, aszine, azo, hy drazone, or sem i-carbazone. “Total oxidized nitrogen” is the sum of nitrate and nitrite.

6-10Nitrite is an interm ediate oxidation state of n itrogen. Certain bacteria can oxidize am m onium to nitrite and then to nitrate. This happens rather qui ckly in aerobic environm ents such as receiving stream s and dry soils. On the other hand, in an anoxic (reducing) environm ent such as bottom waters and saturated soils, certain bacteria can convert nitrate to nitrite and then further convert the nitrogen into gaseous form s (APHA et al., 1995; EPA, 2005b, 2005c).

6.4.2.1 Ammonia

EPA’s 1999 Update of Ambient Water Quality Criteria for Ammonia (EPA, 1999a) states that the lim its are given “in term s of nitrogen, i.e., as m g N/L, because m o st perm it lim its for am m onia are expressed in term s of nitrogen.” In aqueous solutions , am m onia exists in equilibrium in two form s—unionized am m onia (NH 3 ) and am m onium ion (NH 4 + ). 2 Un-ionized am m onia is the m o re toxic com ponent. TRI guidance for reporting discharges of aqueous a m m onia recom m e nds that total aqueous am m onia be calculated in term s of un-ionized am m onia equivalents (TRI, 2000a).
The criteria vary as a function of pH, tem p erature, and whether early life stages are present. For the purpose of evaluating the toxicity of industrial wastewater discharges, we assum e d that early life stages were present, pH = 7, and tem p erature = 20 degrees Celsius. The chronic criterion under these circum stances is 4,150 μ g N/L. If we change the assum e d pH to 8, the criterion drops to 1,710 μ g N/L.

The am m onia-as-NH 3 criterion needs to be adjusted so that the nitrogen as m easured in the discharge corresponds to the form used in the TWF. To do this, we need to convert the am m onia-asnitrogen water quality criterion to an am m onia-as-NH 3 basis by m u ltiply ing by the ratio of the m o lecular weights, i.e. 4,150 × (17/14) = 5,039. Therefore, th ere will be slight differences between the TWFs for

am m onia depending on whether the discharges are reported as nitrogen or as un-ionized am m onia.

2 The water quality criterion is under review but the 1999 Update is the m o st recent available published criterio n
.

6-116.4.2.2 Nitrate
None of the ecotoxicologial studies for nitrate as CAS 14797558 pass the ASTER filter. In fact, the ASTER report lists only one study for freshwater aquatic anim als. 3 EPA reviewed the citation (Lewis et al., 1995). They report no statistically significant response at nitrate concentrations up to 75,000 μ g/L. Accordingly , we propose to use an acute freshwater criterion of 75,000 μ g/L and a chronic freshwater criterion of 7,500 μ g/L to reflect the upper range at which no effect was seen.
TRI guidance, however, indicates that rel eases of water-dissociable nitrate com pounds are reported in term s of the nitrate ion (TRI, 2000b). The c oncentrations in Lewis et al. (1995) are reported as NO 3 -N, indicating that the aquatic com ponent of th e TWF and the TRI pounds are both in term s of the nitrate ion.

6.4.2.3 Nitrite
A search of the ASTER database for “nitrite CAS 14797650” turned up no ecotoxicological studies. Nitrite is an interm ediate product in the nitrogen cy cle and its relative instability m i ght indicate that it is inappropriate to scale the nitrate TWF by the relative weights of NO 2 and NO 3 to estim ate the toxicity for nitrite. EPA (2005b) notes that nitrite is toxic to aquatic species. At the m o m e nt, EPA does not believe it can estim ate an aquatic effects com ponent of the TWF for nitrite regardless of the form in which it is m easured and/or reported.

6.4.2.4 Extrapolation to Other Forms of Nitrogen

For undifferentiated com ponents of the nitrogen cy cle, EPA proposes to use the average of the

am m onia-as-N and nitrate-as-N values. To place the n itrate aquatic health criterion on a nitrogen basis, we would m u ltiply 7,500 μ g/L by the ratio of atom ic weights for N/NO 3 ( i.e., 0.233). The resulting value is 1,748 μ g/L, which, when norm a lized to copper, provid es an aquatic health TWF com ponent of 3.20e-3. This is sim ilar to the value for the m u ch m o re st udied am m onia-as-N of 1.35e-3. The average of the two

3 Anot her st udy i s l i s t e d i n EPA’s EC OTOX dat a base. It dat e s t o 1973, and i t s absence from t h e ASTER l i s t i ng i ndi cat es t h at i t

m i ght not be t h e best i n form at i on source for a TW F.

6-12values is 2.28e-3. EPA proposes that the 2.28e-3 aquatic effects com ponent for nitrate/nitrite m i xtures be used for all m easures that have been converted to nitrogen-equivalents.
TRI has an entry reported as “Nitrogen (as NO 3 ) Sludge Solid.” It is illogical that a facility would go through the effort to de-water a sludge to produ ce a solid only to discharge the end product to the water. Unless the engineers have a better understandi ng of this discharge, EPA assum es that the facility generated a process sludge that they tested for nitr ate content and reported the discharge in term s of pounds of nitrate. Presum a bly , the Kjeldahl m e thod was not used; otherwise the discharge would have been reported as Kjeldahl nitrogen, either as TKN or nitrogen. APHA et al. (1995) describe other m e thods for determ ining nitrates. For this entry , then, we propose to use the original NO 3 basis for the aquatic health criterion, that is, 7.47e-4. Because it is a single entry in the discharge data base, whatever value for nitrogen is used will have m i nuscu le effect on the industry rankings.

6.4.2.5 Forms for Which Th ere Is Insufficient Information

As m e ntioned above, the Kjeldahl m e thods m easure organic nitrogen and am m onia. When a discharge is m easured in term s of TKN, EPA knows ne ither the m a ke-up of the organic m a terial nor the proportion of am m onia. Without this knowledge, EPA cannot estim ate a TWF for TKN. 4

Sim ilarly , EPA cannot estim ate a TWF for the entry reported as “Nitrogen, Inorganic Total” because it is not known whether the results are reported as the total m ass, the nitrite/nitrate portion, or the nitrogen portion.

6.4.3 Nitrogen TWF Sum m a ry

Table 6-6 sum m a rizes the TWFs for various form s of nitrogen. Sodium nitrite has the highest TWF (3.73e-1). As noted above, this value is for rainbow trout, a very sensitive species. The TWFs for

com ponents of the organic nitrogen cy cle are tw o or m o re orders of m a gnitude lower.

4 W e presum e t h at di scharges i d ent i f i e d as “Ni t r ogen, Kj el dahl Tot a l (as N)” were convert ed t o t h i s basi s according to the com position of the discharge.

6-13Two observations arise from the review of nitroge n data. First, it is necessary to verify whether discharges of sodium nitrite in TRI are sodium n itrite (for which we have num erous studies in ASTER and a proposed TWF) or an unspecified form of nitr ite (for which we either have a m u ch lower TWF or no TWF). Second, TWFs m easure toxicity . They do not m easure the possible eutrophication im pacts of nutrients. An alternative m easure for eutrophica tion effects should be developed for nutrients.

Table 6-6 Proposed TWF Summary for Various Forms of Nitrogen

Chemical Freshwater Chronic Aquatic Health Criteria ( μ g/L) Normaliz ed to Copper (TWF) Sodium nitrite 1.50e+01 3.73e-01 Am m onia (as N) 4.15e+03 1.35e-03 Am m onia (as NH 3 ) (a) 1.11e-03 Nitrate (as NO 3 ) 7.50e+03 7.47e-04 Nitrate (as N) (a) 3.20e-03 Nitrogen, total (as N) Nitrogen, Kjeldahl total (as N) Nitrogen oxides (as N) Nitrogen, organic total (as N) (a) 2.28e-03 Nitrogen (as NO 3 ) sludge solid 7.50e+03 7.47e-04 Nitrogen, nitrite total (as N) Nitrite nitrogen, dissolved (as N) Nitrogen, nitrite total (as NO 2 ) N/A N/A (a) Blank cells for criteria indicate that the norm a lized values are either averages or involve a conversion based on the form in which the nitrogen is m easured. Source: EPA estim ates.

6.5 Drinking Water Contam inants
On February 24, 2005, EPA published its second list of contam inant candidates for drinking water (EPA, 2005a). The list has 9 m i crobiological c ontam inants and 42 chem ical contam inants or contam inant groups. Of the chem ical contam inants, the TWF database needs inform ation for those listed in Table 6-7. That table’s third colum n identifies chem icals for which neither hum an nor aquatic health data can be found on which to base a criterion. Sec tions 6.5.1 through 6.5.4 discuss chem icals for which TWFs can be estim ated. Section 6.5.5 sum m a ri zes the TWFs for the drinking water candidate contam inants.

6-14Table 6-7 Drinking Water Candidate Contaminants Needing TWFs

CHEMICAL CAS Information Available 1,1-dichloropropene 563586 No 2,2-dichloropropane 594207 No Acetochlor 34256821 Yes Alachlor ESA and other acetanilide p esticide degradation products N/A See Section 6.5.1

Brom obenzene 108861 Yes Organotins N/A See Section 6.5.2 Perchlorate 14797730 See Section 6.5.3 RDX 121824 Triazines and degradation products of triazines Including, but not lim ited to, cy anazine 21725-46-2 and atrazine-desethy l 6190-65-4 See Section 6.5.4

DCPA m ono-acid degradate 887547 No DCPA di-acid degradate 2136790 Yes Source: EPA estim ates.

6.5.1 Alachlor ESA and Other Acetanilide Pesticide Degradation Products
The Pesticide Action Network database (2005) id entifies four breakdown products for alachlor:

# 2,6 diethy laniline, CAS 579-66-8 # 2-hy droxy alachlor (no CAS num ber) # Alachlor ethanesulfonic acid (ESA) (no CAS num ber) # Alachlor oxanilic acide (no CAS num ber)

EPA searched Chem finder for CAS num bers for the last three chem icals and did not find any

. ASTER searches need to have the CAS num ber or chem ical fo rm ula in SMILES form at, so EPA could not request a search on the last three chem icals. ASTER contained data for diethy laniline, 2,6 (CAS 579-66-8). EPA

nam e d the entry for this group of chem icals by the nam e of the chem ical for which it has data (i.e.,

6-15diethy laniline, 2,6 CAS 579-66-8). EPA updated th e entry for alachlor (CAS 15972-60-8) with the ASTER data for that chem ical.

6.5.2 Organotins
Organotins are com pounds containing at least one bond between tin and carbon. EPA (1999b) lists cy hexatin, fenbutatin oxide, a nd fentin hy droxide (TPTH) under organotins. All three exam ples are triorganotin com pounds, m eaning that each contains three tin-carbon bonds. From this, we assum e that the drinking water list m eans triorganotin com pounds when it sim p ly lists “organotins.” Triorganotin

com pounds are used as biocides and pesticides while m ono- and diorganotin com pounds tend to be used in stabilizer, cataly s t, and glass-coating applications (Batt, 2005). EPA (2003) notes that the toxicity to aquatic organism s generally increases as the num ber of organic com ponents increases from one to three and decreases with the addition of a fourth organic com ponent. That is, the triorganotin com pounds are

m o re toxic.
However, EPA (1999b) does not list tributy ltin (T BT, CAS 688-73-3) or tributy ltin oxide (TBTO, CAS 56-35-9) am ong the organotins even though they ha ve been widely used and studied. EPA published

am bient aquatic life water quality criteria in 2003 fo r tributy ltin as TBT (EPA, 2003). EPA adjusted all the chem icals tested to TBT. Because the newly pub lished study incorporates m a ny organotins in the estim ation of water quality criteria for organic health for TBT, EPA proposes to use the tributy ltin TWF for the organotins TWF. Tributy ltin is already in the TWF database but will be updated.

6.5.3 Perchlorate
EPA recently published an IRIS profile for perc hlorate and perchlorate salts (IRIS, 2005c). EPA requested ASTER data for perchlorate as well as f our perchlorate salts (am m onium , lithium , potassium , and sodium ); ASTER has data for potassium and sodi um perchlorate. Chronic data exist for potassium perchlorate for freshwater sea lam p rey s : horm onal effects were seen at 100,000 μ g/L during a 122-day exposure. An older study for the effects of 96-hour exposure of trout to sodium perchlorate showed 100 percent m o rtality at 3,000,000 μ g/L. Neither study passed the ASTER filter on quality . EPA used the data for potassium perchlorate for the aquatic health criteria for perchlorate.

6-166.5.4 Triaz i nes and Degradation Products
EPA has traditionally used the term “triazines” to refer to atrazine, sim azine, and cy nanizine. EPA (2002c) identifies desisopropy l s-atrazine (DIA), desethy l s-atrazine (DEA) and diam inochlorotriazine (DACT) as m e tabolites with a com m on m echanism

. It is presum e d that the TWF for triazines and degradation products should reflect available inform ation for these six chem icals. Unfortunately , no hum an or aquatic health data could be located for the three m e tabolites. Table 6-8

sum m a rizes the hum an health and aquatic life criteria for atrazine, sim azine, and cy anazine. It is suggested that EPA use the geom etric m ean of the three values for a triazine TWF. The hum an health

com ponent will be calculated on the basis of the cancer slope factor (q1*).

Table 6-8 Human and Aquatic Health Data for Triaz i nes and Degradation Products

Chemical Human Health BCF Aquatic-Fresh Aquatic-Salt RfD q1* Chronic Acute Chronic Acute Atrazine 3.50e-02 2.20e-01 31 65 6,700 2,600 Sim azine 5.00e-03 1.20e-01 18 1,000 124,875 Cy anazine 2.00e-03 8.40e-01 4.0 3.5

Geometric Mean ( μ g/ L ) 7.00e-03 2.80e-01 13 61 29,000 2,600 T oxi c Wei g hti n g Factor Component Value 7.95e+02 1.99e+01 0.0918 0.0002 0.0022 Source: ASTER, 2005.

6-176.5.5 Sum m a ry
Table 6-9 lists the proposed TWFs for drinking water contam inants. The worksheets are located in Appendix A-28 through A-43.

Table 6-9 Drinking Water Candidate Contaminants Needing TWFs

Chemical CAS Proposed TWF 1,1-dichloropropene 563586 0 2,2-dichloropropane 594207 0 Acetochlor 34256821 1.48e-2 Alachlor (update) 15972608 1.52e+0 2,6-diethy laniline (alachlor degradation product) 579668 5.38e-4

Brom obenzene 108861 7.58e-3 Tributy ltin (organotins) 688733 7.78e+1 Perchlorate 14797730 2.00e-3 RDX 121824 4.15e-3 Triazines N/A 2.46e+0 Atrazine 1912249 1.04e+0 Sim azine 122349 3.08e-1 Cy anazine 21725462 4.70e+0 DCPA m ono-acid degradate 887547 0 DCPA di-acid degradate 2136790 4.10e-4 Source: EPA estim ates.

6-186.6 NICOTINE

6.6.1 Hum a n Health
Nicotine is a poison with a lethal dose in adults of 0.5 to 1.0 m g /kg of body weight, or a total dose of 30 to 60 m g (Boulton et al., 2003). In 2003, Michigan officials arrested a person for contam inating 200 pounds of ground beef with Black Leaf 40—a pestic ide containing 40 percent nicotine—and thereby affecting about 100 people. EPA canceled its product registration of Black Leaf in 1992 because of its toxicity (Boulton et al., 2003). In 2002, EPA revoked Federal Food, Drug, and Cosm etic Act tolerances for residues of nicotine-containing com pounds on ag ricultural products except cucum b er, lettuce, and tom a to (EPA, 2002d). EPA plans to publish a Reregistration Eligibility Decision (RED) on nicotine in fiscal y ear 2008. In the Notice, nicotine is listed as a pesticide with no associated tolerance (EPA, 2004).

Derm al exposure to nicotine can result in “gr een tobacco sickness” (GTS) m a rked by nausea,
vom iting, weakness, dizziness, and som e tim es fluctua tions in blood pressure or heart rate. During a particularly wet harvesting season in 1992, Kentuc ky reported an outbreak of 27 cases of GTS severe enough that em ergency room treatm e nt was sought. A review of hospital records identified 55 possible cases of GTS in Kansas between May and October of 1992. Dew from tobacco leaves often saturated workers’ clothing within m i nutes of beginning field work (Boy lan et al., 1993). Because it is connected to factory workers, this exposure route lies m o re in OS HA’s purview than EPA’s, but it is indicative of the toxicity of nicotine.

However, EPA checked its traditional sources 5 for a RfD or a cancer slope and did not identify either for nicotine. In other words, the TWF for nico tine will be underestim ated due to the absence of data for calculating a hum an health com ponent.

5 IR IS; Apri l 2005 R e gi on 3 R i sk B a sed C oncent r at i on/ HEAST t a bl es; ATSDR t oxi col ogi cal profi l e s; California Environm ental Protection Ag ency, Proposition 65 list (where nicotine was not placed on the candidate list i n a M a rch 2004 carci nogeni ci t y eval uat i on); NIH/ NIEHS/ C e nt er for Eval uat i on of R i sks t o Hum a n R e product i on (which deferred a review in 2000 for ch em icals with higher priorities); and T oxicity and Chem ical Specific Factors Data Base, Risk Assessm ent In form ation System , located at h ttp ://risk

. lsd

. o r n l .g o v
.

6-196.6.2 Aquatic Health

A search of the ASTER database identified one study for nicotine that passed the ASTER filter (Passino-Reader et al., 1995). The tested species is fresh water rainbow trout and th e concentration levels

are:

# 60-day LC 50 : 5,000 μ g/L
# 60-day LOEC: 4,200 μ g/L
# 60-day NOEC: 2,900 μ g/L

We calculate a m a xim u m allowable toxicant concentration (MACT) by taking the geom etric m ean of the NOEC and LOEC values, i.e., 2 42 00 × 290 0 or 3,490. In accordance with Zipf (2003), the MACT is the preferred value for the aquatic health criterion. Norm a lizing this to copper, i.e., 5.6/3,490, results in an aquatic health TWF com ponent of 1.6 e-3. The worksheet for nicotine is located in Appendix A-44.

6.7 REFERENCES
APHA (Am e rican Public Health Association, Am erican Water Works Association, and Water Environm ent Association. 1995. Standard m e thods for the exam ination of water and wastewater. Washington, D.C.: Am erican Public Health Association. 19 th edition.
ASTER. 2005. Assessm ent tools for the evaluation of risk database. Results of data request for chem icals in the Drinking Water Contam inant Candidate List 2 category

. U.S. Environm ental Protection Agency , National Health and Environm ental Effects Research Laboratory

. March.
ASTER. 2004. Assessm ent tools for the evaluation of ri sk database. Results of data request for 21 chem icals in the PAC category

. U.S. Environm ental Protection Agency , National Health and Environm ental Effects Research Laboratory

. Novem b er. Batt, J.M. 2005. The world of organotin chem icals: applications, substitutes, and the environm ent. www.ortepa.org/WorldofOrganotinChem icals.pdf

. Downloaded March 29. Boulton, M., M. Stanbury , D. Wade, J. Tilden, D. Bry a n, J. Pay n e, and B. Eisenga. 2003. Nicotine poisoning after ingestion of contam inated gr ound beef—Michigan, 2003. MMWR Weekly 52(18):413­ 416. May 9. Available at http://www.cdc.gov/m m w r/

. Boy l an, B., V. Brandt, J. Muehlbauer, M. Auslande r, C. Spurlock, and R. Finger. 1993. Green tobacco sickness in tobacco harvesters —Kentucky 1992. MMW R Weekly 42(13):237-240. April 9. Available at http://www.cdc.gov/m m w r/

.

6-20EPA. 2005a. Drinking water contam inant candidate lis t 2; final notice. Fed. Reg. 70:9,071-9,077. February 24. EPA. 2005b. Ag 101. Nitrate. http://www.epa.gov/agriculture/ag101/im pactnitrate.htm l

. Downloaded February 17.
EPA. 2005c. Consum er factsheet on: nitrates/nitrites. http://www.epa.gov/safewater/dwh/cioc/nitrates.htm l . Downloaded February 17. EPA. 2004. Pesticide reregistration perform ance m easu res and Goals. Notice. Fed. Reg. 69(87):25,082­ 25,092. May 5.
EPA. 2003. Am bient aquatic life water quality criteri a for tributy ltin (TBT)—final. EPA-822-R-03-031. Decem ber.
EPA. 2002a. National recom m e nded water quality criteria: 2002. EPA-822-R-02-047. Novem b er. EPA. 2002b. National recom m e nded water quality crite ria: 2002. Hum a n health criteria calculation m a trix. EPA-822-R-02-012. Novem b er. EPA. 2002c. OPP office director m e m o on grouping triazines. A com m on m echanism of toxicity determ ination for a series of triazine pesticides. Mem o randum from Marcia E. Mulkey dated March 31. www.epa.gov/pesticides/cum u lative/triazi nes/triazinestransm ittalm em o.htm

. Downloaded March 29, 2005.
EPA. 2002d. Nicotine: tolerance revocations. Fina l rule. Fed. Reg. 67(99):35,912-35,915. May 22. EPA. 2001a. Water quality criteria: notice of availability of water quality criterion for the protection of hum an health: m e thy l m e rcury
. Fed. Reg. 66:1,344-1,359. January 8.
EPA. 2001b. Em ergency Planning and Com m unity Right-to-Know Act—section 313: guidance for reporting toxic chem icals: poly c y c lic arom atic com pounds category

. EPA-260-B-01-03. August. EPA. 2000. Supplem entary guidance for conducting health risk assessm ent of chem ical m i xtures. EPA630-R-00-002. August. EPA. 1999a. 1999 update of am bient water quality crite ria for am m onia. EPA-822-R-99-014. Decem ber. EPA. 1999b. Pesticides: topical and chem ical fact sh eets. New data will help ensure protection of children. www.epa.gov/pesticides/factsheets/neurotoxicdata.htm

. Downloaded March 28, 2005.
EPA. 1994. Addition of certain chem icals; toxic chem ical release reporting; com m unity right-to-know. Fed. Reg. 59:61,465. Novem b er 30 . IRIS. 2005a. Integrated Risk Inform ation Sy stem . Nitrate (CAS 147-55-8). http://www.epa.gov/iris/subst/0076.htm

. Downloaded February 21 . IRIS. 2005b. Integrated Risk Inform ation Sy stem . Am m onia (CAS 7664-41-7). http://www.epa.gov/iris/subst/0422.htm

. Downloaded February 21.

6-21IRIS. 2005c. Integrated Risk Inform ation Sy stem

. Perchlorate and perchlorate salts (CAS 7790-98-9 am m onium perchlorate, CAS 7791-03-9 lithium perchl orate, CAS 7778-74-7 potassium perchlorate, and CASRN 7601-89-0 sodium perchlorate). Last revised 2/18/2005. http://www.epa.gov/iris/subst/1007.htm

. Downloaded March 24. IRIS. 2004. Integrated Risk Inform ation Sy stem . Nitrite (CAS 147-65-0). http://www.epa.gov/iris/subst/0078.htm

. Downloaded Novem b er 17. Lewis, J.W., A.N. Kay , and N.S. Hanna. 1995. Responses of electric fish (fam ily Morm y r idae) to nonorganic nutrients and tributy ltin oxide. Chem osphere 31:3753-3765. Passino-Reader, D.R., W.H. Berlin, and J.P. Hickey . 1995. Chronic bioassay s of rainbow trout fry with com pounds representative of contam inants in Great Lakes fish. Journal of Great Lakes Research 21(3):373-383. Pesticide Action Network. 2005. PAN pes ticides database—chem icals. Alachlor. www.pesticideinfo.org/List_Chem i cals.jsp? Downloaded March 21. Snedcor, G.W., and W.G. Cochrane. 1980. Statistical m e thods. Am es, Iowa: The Iowa State University Press. 7 th edition.
TRI. 2000a. Em ergency Planning and Com m unity Right-to-Know Act Section 313: guidance for reporting aqueous am m onia. EPA- 745-R-00-005. U.S. Environm ental Protection Agency , Office of Environm ental Inform ation. Decem ber.
TRI. 2000b. List of toxic chem icals within the water dissociable nitrate com pounds category and guidance for reporting. EPA-745-R-00-006. U.S. Environm ental Protection Agency , Office of Environm ental Inform ation. Decem ber. Zipf, L. 2003. Revisions to EAD’s toxic weighti ng factor m e thodology param e ters. Mem o randum to 304(m ) Record (EPA Docket Num b er OW-2003-0074). Decem ber 3.

6-22

## ATTACHMENT A TWF DATA WORKSHEETS

A-1Pollutant: Hydrogen Fluoride CAS: 7664393 Variable Units Value Source Human Health q1* m g /kg-day Carcinogen flag Y/N N RfD m g /kg-day 0.05 Value is for Fluoride. ATSDR, 2003. Toxicological Profile for Fluorides, Hy drogen Fluoride, and Fluorine. Septem ber. IRIS, 2004; 0.06 m g /kg-day for fluorine (soluble fluoride, CAS 7782414) RfD verification date, 1985. Code NOAEL

BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L no hits in ASTER or ECOTOX Code Species Aquatic—Freshwater—Acute AWQC μ g/L Code Species Aquatic—Saltwater—Chronic AWQC μ g/L Code Species Aquatic—Saltwater—Acute AWQC μ g/L Code Species

A-2Pollutant: Chlorine Dioxide CAS: 10049044 Variable Units Value Source Human Health q1* m g /kg-day IRIS, 2004; Carcinogen assessm ent consensus date, 2000. Class: D not classifiable because of inadequate data. Carcinogen flag Y/N N
RfD m g /kg-day 0.03 IRIS, 2004; RfD consensus date, 2000. Code NOAEL with uncertainty factor BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 35 ASTER, 2004; Ref. 17656. Matisoff, G, G Brooks, and BI Borland. Toxicity of Chlorine Dioxide to Adult Zebra Mussels. J. Am . Water Works Assoc. 88:93-106. 1996. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; See U.S. EPA. Technical Support Docum e nt for W a ter Quality

based Toxics Control. EPA 505/2­ 90-001. March 1991. Species Zebra Mussel Aquatic—Freshwater—Acute AWQC μ g/L 350 ASTER, 2004; Ref. 17656. Matisoff, G, G Brooks, and BI Borland. Toxicity of Chlorine Dioxide to Adult Zebra Mussels. J. Am . Water Works Assoc. 88:93-106. 1996. Code lowest reported 96-hr LC 50 Species Zebra Mussel Aquatic—Saltwater—Chronic AWQC μ g/L 50,000 ASTER, 2004; Ref. 906. Portm a nn, JE and KW Wilson. The Toxicity of 140 Substances to the Brown Shrim p and Other Marine Anim als. Shellfish Inform ation Leaflet No. 22 (2 nd ed.) Ministry of Agric. Fish. Food, Fish. Lab. Burnham

- on-Crouch, Essex and Fish Exp. Station, Conway , North Wales, 12p. 1971. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; See U.S. EPA. Technical Support Docum e nt for W a ter Quality

based Toxics Control. EPA 505/2­ 90-001. March 1991. Species Green Crab Aquatic—Saltwater—Acute AWQC μ g/L 500,000 ASTER, 2004; Ref. 906. Portm a nn, JE and KW Wilson. The Toxicity of 140 Substances to the Brown Shrim p and Other Marine Anim als. Shellfish Inform ation Leaflet No. 22 (2 nd ed.) Ministry of Agric. Fish. Food, Fish. Lab. Burnham

- on-Crouch, Essex and Fish Exp. Station, Conway , North Wales, 12p. 1971. Code lowest reported 48-hr LC 50 Species Green Crab

A-3Pollutant: 1, 3-Phenylenediamine CAS: 108452 Variable Units Value Source Human Health q1* m g /kg-day IRIS, 2004; no data. Carcinogen flag Y/N N RfD m g /kg-day 6e-3 IRIS, 2004; RfD verification date, 1986. Code NOEL with uncertainty factor BCF L/kg 1 ASTER, 2004; QSAR estim ate. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 38,009 ASTER, 2004; QSAR estim ate. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; See U.S. EPA. Technical Support Document for W a ter Quality -based Toxics Control. EPA 505/2­ 90-001. March 1991. Species Channel Catfish Aquatic—Freshwater—Acute AWQC μ g/L 380,089 ASTER, 2004; QSAR estim ate. Code lowest reported 96-hr LC 50 Species Channel Catfish Aquatic—Saltwater—Chronic AWQC μ g/L Code Species Aquatic—Saltwater—Acute AWQC μ g/L Code Species

A-4Pollutant : Benzo(a)pyrene CAS: 50328 Variable Units Value Source Human Health q1* m g /kg-day 7.3 EPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. Carcinogen flag Y/N Y
RfD m g /kg-day Code BCF L/kg 30 EPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 0.08 ASTER 2004; Ref. 10412. Hannah, JB, JE hose, ML Landolt, BS Miller, SP Felton, WT Iwaoka. Benzo(a)py rene-induced Morphological and Developm ental Abnorm a lities in Rainbow Trout. Arch. Environ. Contam . Toxicol. 11(6):727-734. 1982. Code lowest reported growth effect Species Rainbow Trout Aquatic—Freshwater—Acute AWQC μ g/L 5 ASTER 2004; Ref. 15337. Trucco, RG, FR Englehart, B Stacey . Toxicity , Accum u lation and Clearance of Arom atic Hy drocarbons in Daphnia pulex. Environ. Pollut. Ser. A Ecol. Biol. 31(3):191-202. 1983, Code lowest reported 96-hr LC 50 Species Water Flea Aquatic—Saltwater—Chronic AWQC μ g/L 100 ASTER 2004; Ref. 5053. Rossi, SS and JM Neff. Toxicity of Poly nuclear Arom atic Hy drocarbons to the Poly chaete Neanthes arenaceodent ata, Mar. Pollut. Bull. 9(8):220-223. 1978. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; See U.S. EPA. Technical Support Document for W a ter Quality -based Toxics Control. EPA 505/2­ 90-001. March 1991. Species Poly chaete Worm Aquatic—Saltwater—Acute AWQC μ g/L 1,000 ASTER 2004; Ref. 5053. Rossi, SS and JM Neff. Toxicity of Poly nuclear Arom atic Hy drocarbons to the Poly chaete Neanthes arenaceodent ata, Mar. Pollut. Bull. 9(8):220-223. 1978. Code lowest reported 96-hr LC 50 Species Poly chaete Worm

A-5Pollutant: Aniline CAS: 62533 Variable Units Value Source Human Health q1* m g /kg-day 5.7e-3 IRIS, 2004; Carginogenicity assessm ent verifications date, 1987. Class: B2 probable hum an carcinogen Carcinogen flag Y/N Y RfD m g /kg-day Code BCF L/kg 7 ASTER, 2004; Arithm e tic average of seven studies. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 4,400 ASTER, 2004; Ref. 538. Birge, W.J., JA Black, JE Hudson, and DM Bruser. Em bry o -Larval Toxicity Tests with Organic Com pounds. In LL Marking and RA Kim e rle (eds.) Aquatic Toxicology and Hazard Assessm ent, 2 nd Sy m posium , ASTM STP 667, Philadelphia, PA;131-147. 1979 Code lowest LC 50 Species Largem outh Bass

Aquatic—Freshwater—Acute AWQC μ g/L 68,630 ASTER, 2004; Ref. 3910. Marchinie, S, ML Tosato, TJ Norberg-King, DE Ham m e rm eister, and MD Holund. Lethal and Sublethal Toxicity of Benzene Derivatives to the Fathead Minnow, Using a Short-Term Test. Environ. Toxicol. Chem 11(2):187-195. 1992. Code lowest 96-hr LC 50 Species Fathead Minnow Aquatic—Saltwater—Chronic AWQC μ g/L 2,940 ASTER, 2004; Ref. 5810. McLeese, DW, V Zitko, and MR Peterson. Structure-Lethality Relationships for Phenols, Anilines, and Other Arom atic Com pounds in Shrim p and Clam s. Chem osphere 8(2):53-57. 1979. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; See U.S. EPA. Technical Support Document for W a ter Quality -based Toxics Control. EPA 505/2­ 90-001. March 1991. Species Bay Shrim p /Sand Shrim p Aquatic—Saltwater—Acute AWQC μ g/L 29,400 ASTER, 2004; Ref. 5810. McLeese, DW, V Zitko, and MR Peterson. Structure-Lethality Relationships for Phenols, Anilines, and Other Arom atic Com pounds in Shrim p and Clam s. Chem osphere 8(2):53-57. 1979. Code lowest 96-hr LC 50 Species Bay Shrim p /Sand Shrim p

A-6Pollutant: Vanadium CAS: 7440622 Variable Units Value Source Human Health q1* m g /kg-day Carcinogen flag Y/N N RfD m g /kg-day 1e-3 EPA-NCEA provisional value fromRegion III, RiskBased Concentration Table, dated 10/8/2004. Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 160 ASTER, 2004; Ref. 4943. Birge, JW, JA Black, and AG Westerm a n. Evaluation of Aquatic Pollutants Using Fish and Am phibian Eggs as Bioassay Organism s. In SW Nielsen, G. Migaki, and DG Scarpelli (Eds.) Sy m p
. Anim als Monitors Environ. Pollut. 1977, Storrs, CT 12:108-118. 1979 Code lowest LC 50 Species Rainbow Trout

Aquatic—Freshwater—Acute AWQC μ g/L Code Species Aquatic—Saltwater—Chronic AWQC μ g/L 5 ASTER, 2004; Ref. 6761. Ballester, A and J Castellvi. Contribution to the Study of V and Ni Uptake in Marine Organism s (Contribucion al Estudio de la Biocenetica de V y Ni en Organism os Marinos). Invest, Pesq. 43(2):49­ 478 (Spanish, English abstract). 1979 Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; See U.S. EPA. Technical Support Document for W a ter Quality -based Toxics Control. EPA 505/2­ 90-001. March 1991. Species Com m on bay m u ssel Aquatic—Saltwater—Acute AWQC μ g/L 50 ASTER, 2004; Ref. 6761. Ballester, A and J Castellvi. Contribution to the Study of V and Ni Uptake in Marine Organism s (Contribucion al Estudio de la Biocenetica de V y Ni en Organism os Marinos). Invest, Pesq. 43(2):49­ 478 (Spanish, English abstract). 1979 Code lowest reported residue effects Species Com m on bay m u ssel

A-7Pollutant: Merc ury CAS: 7439976 Variable Units Value Source Human Health q1* m g /kg-day IRIS, 2004: Carcinogenicity Assessm ent Verification date, 1994. Class: D - not classifiable as to hum an carcinogenicity (inadequate data). Carcinogen flag Y/N N
RfD m g /kg-day 1.00e-4 IRIS, 2004, not available. EPA. 2002. National Recom m e nded Water Quality Criteria: 2002 - Hum a n Health Criteria Calculation Matrix. EPA-822-R-02-012. Novem b er. Based on 1997 IRIS value. Code

BCF L/kg 7342.6 EPA. 2002. National Recom m e nded Water Quality Criteria: 2002 - Hum a n Health Criteria Calculation Matrix. EPA-822-R-02-012. Novem b er BAF RSC 1 EPA. 2002. National Recom m e nded Water Quality Criteria: 2002 - Hum a n Health Criteria Calculation Matrix. EPA-822-R-02-012. Novem b er. 1998 Value calculated with 1980 m e thodology

. FI 18.7 EPA. 2002. National Recom m e nded Water Quality Criteria: 2002 - Hum a n Health Criteria Calculation Matrix. EPA-822-R-02-012. Novem b er Aquatic—Freshwater—Chronic AWQC μ g/L 0.77 EPA. 2002. National Recom m e nded Water Quality Criteria: 2002. EPA-822-R-02-047. Novem b er Code Species Aquatic—Freshwater—Acute AWQC μ g/L 1.4 EPA. 2002. National Recom m e nded Water Quality Criteria: 2002. EPA-822-R-02-047. Novem b er Code Species Aquatic—Saltwater—Chronic AWQC μ g/L 0.94 EPA. 2002. National Recom m e nded Water Quality Criteria: 2002. EPA-822-R-02-047. Novem b er Code Species Aquatic—Saltwater—Acute AWQC μ g/L 1.8 EPA. 2002. National Recom m e nded Water Quality Criteria: 2002. EPA-822-R-02-047. Novem b er Code Species

A-8Pollutant: Methylmerc ury CAS: 22967926 Variable Units Value Source Human Health q1* m g /kg-day IRIS, 2004; Carcinogenicity Assessm ent date 1995. Classification = C; possible hum an carcinogen but sy stem ic affects would likely been seen at exposures lower than those required for tum o r form ation. Carcinogen flag Y/N Y

RfD m g /kg-day 1.00e-4 IRIS, 2004; Oral RfD consensus date 2001. Code BMDL50 benchm ark dose, lower lim it 95% BCF BAF 1,225,02 9 Methy l m e rcury Water Quality Criteria. Jan 8, 2001. 66 FR 1344-1359. Calculated as weighted average of fish intake and BAF for fish intake of 17.5 gram s/day

. See Section 6.2.1 RSC 73% Methy l m e rcury Water Quality Criteria. Jan 8, 2001. 66 FR 1344-1359. RSC presented as an am ount to subtract. Converted to percentage. See Section 6.2.2 Aquatic—Freshwater—Chronic AWQC μ g/L Code Species Aquatic—Freshwater—Acute AWQC μ g/L Code Species Aquatic—Saltwater—Chronic AWQC μ g/L Code Species Aquatic—Saltwater—Acute AWQC μ g/L Code Species

A-9Pollutant: Benzo(a)anthracene CAS: 56553 Variable Units Value Source Human Health q1* m g /kg-day 7.3 Value for benzo(b)fluoranthene (CAS 205992). USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. Carcinogen flag Y/N Y

RfD m g /kg-day Code BCF L/kg 30 Value for benzo(b)fluoranthene (CAS 205992). USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 160 ASTER. 2004. QSAR est., Ref. 15823. Veith, GD, DJ Call, and LT Brooke. Structural-Toxicity Relationships for the Fathead Minnow, Pim e phales prom elas: Narcotic Industrial Chem icals. Can J. Fish. Aquat. Sci. 40(6):743-748. 1983. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; USEPA. Technical Support Docum e nt for W a ter Quality

based Toxics Control. EPA 505/2­ 90-001. March 1991. Species Fathead Minnow Aquatic—Freshwater—Acute AWQC μ g/L 1599 ASTER. 2004. QSAR est., Ref. 15823. Veith, GD, DJ Call, and LT Brooke. Structural-Toxicity Relationships for the Fathead Minnow, Pim e phales prom elas: Narcotic Industrial Chem icals. Can J. Fish. Aquat. Sci. 40(6):743-748. 1983. Code 96-hr LC 50 Species Fathead Minnow
Aquatic—Saltwater—Chronic AWQC μ g/L 7.5 ASTER. 2004. Ref. 3511. A.E. McElroy

. Poly cy clic Arom atic Hy drocarbon Metabolism in the Poly chaete Nereis virens. Aquat. Toxicol. 18(1):35-50. 1990. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; USEPA. Technical Support Docum e nt for W a ter Quality

based Toxics Control. EPA 505/2­ 90-001. March 1991. Species Poly chaete worm Aquatic—Saltwater—Acute AWQC μ g/L 75 ASTER. 2004. Ref. 3511. A.E. McElroy

. Poly cy clic Arom atic Hy drocarbon Metabolism in the Poly chaete Nereis virens. Aquat. Toxicol. 18(1):35-50. 1990. Code lowest reported biological effect Species Poly chaete worm

A-10Pollutant: Benzo(a)phenanthrene (Chrysene) CAS: 218019

Variable Units Value Source Human Health q1* m g /kg-day 7.3 Value for benzo(b)fluoranthene (CAS 205992). USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. Carcinogen flag Y/N Y

RfD m g /kg-day Code BCF L/kg 30 Value for benzo(b)fluoranthene (CAS 205992). USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 160 ASTER. 2004. QSAR est., Ref. 15823. Veith, GD, DJ Call, and LT Brooke. Structural-Toxicity Relationships for the Fathead Minnow, Pim e phales prom elas: Narcotic Industrial Chem icals. Can J. Fish. Aquat. Sci. 40(6):743-748. 1983. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; USEPA. Technical Support Document for Water Quality -based Toxics Control. EPA 505/2-90-001. March 1991. Species Fathead Minnow Aquatic—Freshwater—Acute AWQC μ g/L 1599 ASTER. 2004. QSAR est., Ref. 15823. Veith, GD, DJ Call, and LT Brooke. Structural-Toxicity Relationships for the Fathead Minnow, Pim e phales prom elas: Narcotic Industrial Chem icals. Can J. Fish. Aquat. Sci. 40(6):743-748. 1983. Code 96-hr LC 50 Species Fathead Minnow
Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-11Pollutant: Benzo(b)fluoranthene CAS: 205992 Variable Units Value Source Human Health q1* m g /kg-day 7.3 USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. Carcinogen flag Y/N Y
RfD m g /kg-day Code BCF L/kg 30 USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-12Pollutant: Benzo(k)fluoranthene CAS: 207089 Variable Units Value Source Human Health q1* m g /kg-day 7.3 Value for benzo(b)fluoranthene (CAS 205992). USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. Carcinogen flag Y/N Y

RfD m g /kg-day Code BCF L/kg 30 Value for benzo(b)fluoranthene (CAS 205992). USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-13Pollutant: Benzo(j,k)fluoranthene (fluoranthene) CAS: 206440

Variable Units Value Source Human Health q1* m g /kg-day Carcinogen flag Y/N N RfD m g /kg-day 0.04 USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. Code
BCF L/kg 1150 USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 4.5 ASTER. 2004. Ref. 3590. Oris, JT, RW Winner, and MV Moore. A Four-Day Survival and reproduction Toxicity Test for Ceriodaphnia dubia. Environ. Toxicol. Chem . 10(2): 217-224. 1991. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; USEPA. Technical Support Document for Water Quality -based Toxics Control. EPA 505/2-90-001. March 1991. Species Water flea Aquatic—Freshwater—Acute AWQC μ g/L 45 ASTER. 2004. Ref. 3590. Oris, JT, RW Winner, and MV Moore. A Four-Day Survival and reproduction Toxicity Test for Ceriodaphnia dubia. Environ. Toxicol. Chem . 10(2): 217-224. 1991. Code lowest 48-hr LC 50 Species Water flea
Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-14Pollutant: Dibenzo(a,h)anthracene CAS: 53703 Variable Units Value Source Human Health q1* m g /kg-day 7.3 Value for benzo(b)fluoranthene (CAS 205992). USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. Carcinogen flag Y/N Y

RfD m g /kg-day Code BCF L/kg 30 Value for benzo(b)fluoranthene (CAS 205992). USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 50 ASTER. 2004. Ref. 17714. Wernersson, AS and G Dave. Phototoxicity Identification by Solid Phase Extraction and Photoinduced Toxicity to Daphnia m a gna. Arch. Environ. Contam . Toxicol. 32(3):268-273. 1997. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; USEPA. Technical Support Document for Water Quality -based Toxics Control. EPA 505/2-90-001. March 1991. Species Water Flea Aquatic—Freshwater—Acute AWQC μ g/L 496 ASTER. 2004. Ref. 17714. Wernersson, AS and G Dave. Phototoxicity Identification by Solid Phase Extraction and Photoinduced Toxicity to Daphnia m a gna. Arch. Environ. Contam . Toxicol. 32(3):268-273. 1997. Code lowest EC50 Species Water Flea
Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-15Pollutant: Indeno(1,2,3-cd)pyrene CAS: 193395 Variable Units Value Source Human Health q1* m g /kg-day 7.3 Value for benzo(b)fluoranthene (CAS 205992). USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. Carcinogen flag Y/N Y

RfD m g /kg-day Code BCF L/kg 30 Value for benzo(b)fluoranthene (CAS 205992). USEPA. 2002. National Recom m e nded Water Quality Criteria: 2002 Hum a n Health Calculation Matrix. EPA 822-R-02-012. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-16Pollutant: Benzo(j)fluoranthene CAS: 205823 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000, USEPA 1995) Carcinogen flag Y/N RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-17Pollutant: Benzo(r,s,t)pentaphene CAS: 189559 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000, USEPA 1995) Carcinogen flag Y/N RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L ASTER. 2004. No anim al data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2004. No anim al data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No anim al data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No anim al data. Code Species

A-18Pollutant: Dibenz(a,h)acridine CAS: 226368 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000, USEPA 1995) Carcinogen flag Y/N RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-19Pollutant: Dibenz(a,j)acridine CAS: 224420 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000, USEPA 1995) Carcinogen flag Y/N RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L ASTER. 2004. No anim al data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2004. No anim al data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No anim al data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No anim al data. Code Species

A-20Pollutant: Dibenzo(a,e)fluoranthene CAS: 5385751 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000, USEPA 1995) Carcinogen flag Y/N RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-21Pollutant: Dibenzo(a,e)pyrene CAS: 192654 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000, USEPA 1995) Carcinogen flag Y/N RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-22Pollutant: Dibenzo(a,h)pyrene CAS: 189640 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000, USEPA 1995) Carcinogen flag Y/N RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-23Pollutant: Dibenzo(a,l)pyrene CAS: 191300 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000, USEPA 1995) Carcinogen flag Y/N RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-24Pollutant: 7H-dibenzo(c,g)carbazole CAS: 194592 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000, USEPA 1995) Carcinogen flag Y/N RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 185 ASTER. 2004. QSAR est., Ref. 15823. Veith, GD, DJ Call, and LT Brooke. Structural-Toxicity Relationships for the Fathead Minnow, Pim e phales prom elas: Narcotic Industrial Chem icals. Can J. Fish. Aquat. Sci. 40(6):743-748. 1983. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; USEPA. Technical Support Document for Water Quality -based Toxics Control. EPA 505/2-90-001. March 1991. Species Fathead Minnow Aquatic—Freshwater—Acute AWQC μ g/L 1852 ASTER. 2004. QSAR est., Ref. 15823. Veith, GD, DJ Call, and LT Brooke. Structural-Toxicity Relationships for the Fathead Minnow, Pim e phales prom elas: Narcotic Industrial Chem icals. Can J. Fish. Aquat. Sci. 40(6):743-748. 1983. Code 96-hr LC 50 Species Fathead Minnow
Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. Results in fish tissue concentration only

. Code Species

A-25Pollutant: 5-Methylchrysene CAS: 3697243 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000, USEPA 1995) Carcinogen flag Y/N RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-26Pollutant: 1-Nitropyrene CAS: 5522430 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000, USEPA 1995) Carcinogen flag Y/N RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 215 ASTER. 2004. QSAR est., Ref. 15823. Veith, GD, DJ Call, and LT Brooke. Structural-Toxicity Relationships for the Fathead Minnow, Pim e phales prom elas: Narcotic Industrial Chem icals. Can J. Fish. Aquat. Sci. 40(6):743-748. 1983. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; See U.S. EPA. Technical Support Document for W a ter Quality -based Toxics Control. EPA 505/2­ 90-001. March 1991. Species Fathead Minnow Aquatic—Freshwater—Acute AWQC μ g/L 2149 ASTER. 2004. QSAR est., Ref. 15823. Veith, GD, DJ Call, and LT Brooke. Structural-Toxicity Relationships for the Fathead Minnow, Pim e phales prom elas: Narcotic Industrial Chem icals. Can J. Fish. Aquat. Sci. 40(6):743-748. 1983. Code 96-hr LC 50 Species Fathead Minnow
Aquatic—Saltwater—Chronic AWQC μ g/L ASTER. 2004. No data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER. 2004. No data. Code Species

A-27Pollutant: 1,1-dichloropropene CAS: 563586 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000 [ C alifornia] , USEPA 1995[ Great Lakes] ). Carcinogen flag Y/N
RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L No ASTER data specifically for 1,1, dichloropropene. Reference is to 1980 EPA WQC Docum e nt for dichloropropanes and dichloropropenes. Code Species Aquatic—Freshwater—Acute AWQC μ g/L Code Species Aquatic—Saltwater—Chronic AWQC μ g/L Code Species Aquatic—Saltwater—Acute AWQC μ g/L Code Species

A-28Pollutant: 2,2-dichloropropane CAS: 594207 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000 [ C alifornia] , USEPA 1995[ Great Lakes] ). Carcinogen flag Y/N
RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L No ASTER data specifically for 2,2 dichloropropane. Reference is to 1980 EPA WQC Docum e nt for dichloropropanes and dichloropropenes. Code Species Aquatic—Freshwater—Acute AWQC μ g/L Code Species Aquatic—Saltwater—Chronic AWQC μ g/L Code Species Aquatic—Saltwater—Acute AWQC μ g/L Code Species

A-29Pollutant: Acetochlor CAS: 34256821 Variable Units Value Source Human Health q1* m g /kg-day Carcinogen flag Y/N N RfD m g /kg-day 2.0e-2 IRIS 2005. 1993 revision. Code BCF L/kg 1 assum p tion. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 38 ASTER. 2005. Ref.: 344. EPA. Office of Pesticide Program s. Environm ental Effects Database. 1995. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; See U.S. EPA. Technical Support Document for W a ter Quality -based Toxics Control. EPA 505/2­ 90-001. March 1991. Species Rainbow Trout Aquatic—Freshwater—Acute AWQC μ g/L 380 ASTER. 2005. Ref.: 344. EPA. Office of Pesticide Program s. Environm ental Effects Database. 1995. Value cited: 0.38 ppm

. ppm = m g /L Code 96hr LC 50 Species Rainbow Trout Aquatic—Saltwater—Chronic AWQC μ g/L Code Species Aquatic—Saltwater—Acute AWQC μ g/L Code Species

A-30Pollutant: Alachlor CAS: 15972-66-8 UPDATE Variable Units Value Source Human Health q1* m g /kg-day 8.0e-2 Region 3. Risk Based Concentration Table. 2004. HEAST Carcinogen flag Y/N Y RfD m g /kg-day 1.0e-2 Region 3. Risk Based Concentration Table. 2004. IRIS. Code BCF L/kg 132 ASTER, 2005. Ref: 7. Veith, G.D. and Kosian. Estimating Bioconcentration Potential from Octanol/Water Partition Coefficients. In D. Mackay et. al. (Eds.), Physical Behavior of PCBs in the Great Lakes. Ann Arbor Sci. Publ., Ann Arbor, MI:269-282. 1983. (Former value 158) BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 140 ASTER, 2005. Ref: 10635. Call,D.J., L.T. Brooke, R.J. Kent, S.H. Poirier, M

. L. Knuth, P.J. Shubat, and E.J. Slick. Toxicity, Uptake, and Elimination of the Herbicides Alachlor and Dinoseb in Freshwater Fish. J. Environ. Qual. 13(3):493-498 1984. (Former value 747) Code 64-day lowest recorded growth effect Species Fathead m i nnow Aquatic—Freshwater—Acute AWQC μ g/L 5000 ASTER, 2005. Ref: 15031. Broderius, S.J., M.D. Kahl, and M.D. Hoglund. Use of Joint Toxic Response to Define the Prim ary Mode of Toxic Action for Diverse Industrial Organic Chem icals. Environ. Toxicol. Chem

. 14(9):1591-1605. 1995. Code 96-hr LC 50 Species
Aquatic—Saltwater—Chronic AWQC μ g/L Code Species Aquatic—Saltwater—Acute AWQC μ g/L Code Species

A-31Pollutant: 2, 6-Diethylaniline (Alachlor degradation product) CAS: 579668

Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000 [ C alifornia] , USEPA 1995[ Great Lakes] ). Carcinogen flag Y/N
RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 1042 ASTER. 2005. Ref. 3537. Veith, G.D. and Broderius. Structure-Toxicity Relationships for Industrial Chem icals Causing Ty pe (II) Narcosis Sy ndrom e. In KLE Kaiser (ed.) QSAR in Environm ental Toxiciology

II, D. Reidel Publ. Co. Dordrecht, Holland:385-391. 1987. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; See U.S. EPA. Technical Support Document for W a ter Quality -based Toxics Control. EPA 505/2­ 90-001. March 1991. Species Fathead Minnow Aquatic—Freshwater—Acute AWQC μ g/L 10417 ASTER. 2005. Ref. 3537. Veith, G.D. and Broderius. Structure-Toxicity Relationships for Industrial Chem icals Causing Ty pe (II) Narcosis Sy ndrom e. In KLE Kaiser (ed.) QSAR in Environm ental Toxiciology

II, D. Reidel Publ. Co. Dordrecht, Holland:385-391. 1987. Code 96-hr LC-50 Species Fathead Minnow

Aquatic—Saltwater—Chronic AWQC μ g/L Code Species Aquatic—Saltwater—Acute AWQC μ g/L Code Species

A-32Pollutant: Bromobenzene CAS: 108861 Variable Units Value Source Human Health q1* m g /kg-day Carcinogen flag Y/N N RfD m g /kg-day 2.00e-2 Region 3. Risk-based Concentration Table. Oct. 8, 2004. EPA provisional peer-reviewed value. Code BCF L/kg 94 ASTER. 2005. Ref. 7. Veith, GD and P Kosian. Estim ating Bioconcentration Potential from Octanol/Water Partition Coefficients. In D. Mackay et al. (Eds.) Phy s ical behavior of PCBs in the Great Lakes. Ann Arbor Scie. Publ. Ann Arbor, MI:269-282. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 560 ASTER. 2005: Ref. 4343. Marchini, S, MD Hoglund, S.J Borderius, and ML Tosato. Com p arison of the Susceptibility of Daphnids and Fish to Benezene Derivatives. Sci. Total Environ. Suppl:399-808. 1993. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; See U.S. EPA. Technical Support Document for W a ter Quality -based Toxics Control. EPA 505/2­ 90-001. March 1991. 73Species Fathead Minnow Aquatic—Freshwater—Acute AWQC μ g/L 5600 ASTER. 2005: Ref. 4343. Marchini, S, MD Hoglund, S.J Borderius, and ML Tosato. Com p arison of the Susceptibility of Daphnids and Fish to Benezene Derivatives. Sci. Total Environ. Suppl:399-808. 1993. Code lowest LC 50 Species Fathead Minnow Aquatic—Saltwater—Chronic AWQC μ g/L Nothing in ASTER. Code Species Aquatic—Saltwater—Acute AWQC μ g/L ASTER data cites one reference that used body burden (m m o l/kg), and did not pass filter. Code Species

A-33Pollutant: tributyltin (TBT) (Organotins ) CAS: 668-73-3

Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000 [ C alifornia] , USEPA 1995[ Great Lakes] ). Carcinogen flag Y/N
RfD m g /kg-day Code BCF L/kg 501 Tsuda T, Nakanishi, S. Aoki, and S. Takebay ashi. Bio concentration and m e tabolism of buty ltin com pounds in carp. Water Res. 22: 647-651. 1988. in EPA. 2003. Am bient Aquatic Life Water Quality Criteria for Tributy ltin (TBT)-Final. EPA 822-R-03-031. Decem ber. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 0.072 EPA. 2003. Am bient Aquatic Life Water Quality Criteria for Tributy ltin (TBT)-Final. EPA 822-R-03-031. Decem ber. Code EPA Criteria Species None listed. Aquatic—Freshwater—Acute AWQC μ g/L 0.46 EPA. 2003. Am bient Aquatic Life Water Quality Criteria for Tributy ltin (TBT)-Final. EPA 822-R-03-031. Decem ber. Code EPA Criteria Species None listed. Aquatic—Saltwater—Chronic AWQC μ g/L 0.0074 EPA. 2003. Am bient Aquatic Life Water Quality Criteria for Tributy ltin (TBT)-Final. EPA 822-R-03-031. Decem ber. Code EPA Criteria Species None listed. Aquatic—Saltwater—Acute AWQC μ g/L 0.42 EPA. 2003. Am bient Aquatic Life Water Quality Criteria for Tributy ltin (TBT)-Final. EPA 822-R-03-031. Decem ber. Code EPA Criteria Species None listed.

A-34Pollutant: Perchlorate CAS: 14797730 Variable Units Value Source Human Health q1* m g /kg-day Carcinogen flag Y/N N RfD m g /kg-day 7.0e-4 IRIS. 2005. 2005 revision. For perchlorate and perchlorate salts. Code BCF L/kg 1 assum p tion BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 1.0e5 Data for potassium perchlorate. ASTER. 2005. Ref.: 16030. Youson, JH, JA Holm es, and JF Leatherland. Serum Concentrations of Thy r oid Horm ones in KClO4­ treated Larval Dea Lam p rey s (Petrom y zon m a rinus K.) Com p . Biochem

. Phy s iol. 111c(2):265-270. 1995. Code 122-day exposure, horm onal effect Species Sea Lam p rey Aquatic—Freshwater—Acute AWQC μ g/L Only 100% m o rtality concentration after 96-hr exposure; cannot adjust to LC 50 . Code Species Aquatic—Saltwater—Chronic AWQC μ g/L No data Code Species Aquatic—Saltwater—Acute AWQC μ g/L No data Code Species

A-35Pollutant: RDX CAS: 121824 Variable Units Value Source Human Health q1* m g /kg-day 1.1e-1 IRIS. 2005. 1993 revision. C: possible hum an carcinogen. Carcinogen flag Y/N Y RfD m g /kg-day 3.0e-3 IRIS. 2005. 1993 revision. Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 1350 ASTER, 2005. Ref: 17503.Burton, D.T., S.D. Turley , and G.T. Peters. The Acute and Chronic Toxicity of Hexahy dro-1,3,5-Trinitro-1,3,5-Triazine (RDX) to the Fathead Minnow (Pim ephales prom elas). Chem osphere 29(3):567-579. 1994 B Code 32-day NOEC Species Fathead Minnow Aquatic—Freshwater—Acute AWQC μ g/L 12700 ASTER, 2005. Ref: 17503.Burton,D.T., S.D. Turley , and G.T. Peters. The Acute and Chronic Toxicity of Hexahy dro-1,3,5-Trinitro-1,3,5-Triazine (RDX) to the Fathead Minnow (Pim ephales prom elas). Chem osphere 29(3):567-579. 1994 B Code 96-hr LC 50 Species Fathead Minnow Aquatic—Saltwater—Chronic AWQC μ g/L no data Code Species Aquatic—Saltwater—Acute AWQC μ g/L no data Code Species

A-36Pollutant: atrazine-desethyl CAS: 6190654 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000 [ C alifornia] , USEPA 1995[ Great Lakes] ). Carcinogen flag Y/N
RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L no ASTER data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L no ASTER data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L no ASTER data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L no ASTER data. Code Species

A-37Pollutant: Triazines CAS: Variable Units Value Source Human Health q1* m g /kg-day 1.3e-1 Geom etric m ean of values for atrazine, cy anazine, and sim azine. IRIS. 2005. Carcinogen flag Y/N Y RfD m g /kg-day 7.0e-3 Geom etric m ean of values for atrazine, cy anazine, and sim azine. Region 3. Risk Based Concentration Table. 2004. HEAST Code
BCF L/kg 13 Geom etric m ean of values for atrazine, cy anazine, and sim azine. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 61 Geom etric m ean of values for atrazine, cy anazine, and sim azine. Code Species Aquatic—Freshwater—Acute AWQC μ g/L 29,000 Geom etric m ean of values for atrazine and sim azine. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L

. Code Species Aquatic—Saltwater—Acute AWQC μ g/L 2,600 Value for atrazine. Code Species

A-38Pollutant: Atrazine CAS: 1912249 Variable Units Value Source Human Health q1* m g /kg-day 2.2e-1 IRIS. 2005. Carcinogen flag Y/N Y RfD m g /kg-day 2.5e-2 Region 3. Risk Based Concentration Table. 2004. HEAST Code BCF L/kg 31 ASTER. 2005. Ref. 7. Veith, GD and P Kosian. Estim ating Bioconcentration Potential from Octanol/Water Partition Coefficients. In D. Mackay et al. (Eds.) Phy s ical behavior of PCBs in the Great Lakes. Ann Arbor Scie. Publ. Ann Arbor, MI:269-282. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 65 ASTER. 2005. Ref. 631. Macek, KJ KS Buxton, S Sauter, S Gnilka, and JW Dean. Chronic Toxicity of Atrazine to Selected Aquatic Invertebrates and Fishes. Ecol. Res. Serv. EPA 600/3-76-047. Environ. Res. Lab., U.S., EPA, Duluth:MN 50 pp. 1976. Code m o rtality Species Brook Trout Aquatic—Freshwater—Acute AWQC μ g/L 6,700 ASTER. 2005. Ref. 17138. Brooke. LT. Results of Freshwater Exposures with the Chem icals Atrazine, Bipheny l, Carbary l , Carbazole, Dibenzofuran, 3,3­ dichorobenzidine... Center for Lake Superior Environm ental Studies, University of Wisconsin, 1991. Code 96-hr LC 50 Species Stone Fly Aquatic—Saltwater—Chronic AWQC μ g/L

. Code Species Aquatic—Saltwater—Acute AWQC μ g/L 2,600 ASTER. 2005. Ref. 14715. Hall, LW Jr., MC Zeigenfuss, RD Anderson, TD Spittler, and HC Leichtweis. Influence of Salinity on Atrazine Toxicity to a Chesapeake Bay Copepod (Eury t em ora affinis) and Fish (Cy p rindon variegatus). Estuaries 17(1B):181-186. 1994. Code 96-hr LC 50 Species Calanoid copepod

A-39Pollutant: Simazine CAS: 122349 Variable Units Value Source Human Health q1* m g /kg-day 1.2e-1 Region 3. Risk Based Concentration Table. 2004. HEAST Carcinogen flag Y/N Y RfD m g /kg-day 5.00e-3 IRIS. 2005. 1994 revision. Code BCF L/kg 18 ASTER, 2005. Ref. 7. Veith, GD and P Kosian. Estim ating Bioconcentration Potential from Octanol/Water Partition Coefficients. In D. Mackay et al. (Eds.) Phy s ical behavior of PCBs in the Great Lakes. Ann Arbor Scie. Publ. Ann Arbor, MI:269-282. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 1000 ASTER. 2005. Ref. 10969. McGinty , AS. Effects of Periodic Applications of Sim azine on the Production of Tilapia nilotica Fingerlings. J. Agric. Univ. P.R. 68(4):467-469. 1984. Code m o rtality Species Nile Tilapia Aquatic—Freshwater—Acute AWQC μ g/L 124,875 ASTER. 2005. Ref. 15823. Veith GD, DJ Call, and LT Brooke. Structure-Toxicity Relationships for the Fathead Minnow, Pim e phales prom elas: Narcotic Industrial Chem icals. Can. J. Fish. Aquat. Scie. 40(6):743-748. 1983. Code 96-hr LC 50 Species Fathead Minnow Aquatic—Saltwater—Chronic AWQC μ g/L

. Code Species Aquatic—Saltwater—Acute AWQC μ g/L Code Species

A-40Pollutant: Cyanazine CAS: 2125462 Variable Units Value Source Human Health q1* m g /kg-day 8.4e-1 Region 3. Risk Based Concentration Table. 2004. HEAST Carcinogen flag Y/N Y RfD m g /kg-day 2.0e-3 Region 3. Risk Based Concentration Table. 2004. HEAST Code BCF L/kg 4 ASTER, 2005. Ref. 7. Veith, GD and P Kosian. Estim ating Bioconcentration Potential from Octanol/Water Partition Coefficients. In D. Mackay et al. (Eds.) Phy s ical behavior of PCBs in the Great Lakes. Ann Arbor Scie. Publ. Ann Arbor, MI:269-282. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 3.5 ASTER. 2005. Ref. 4442. Davies, PE, LSJ Cook, and D Goenarso. Sublethal Responses to Pesticides of Several Species of Australian Freshwater Fish and Crustaceans and Rainbow Trout. Environ. Toxicol. Chem

. 13(8):1341-1354. 1994. Code 10-day LC 50 Species Rainbow Trout Aquatic—Freshwater—Acute AWQC μ g/L ASTER. 2005. Data either do not press ASTER quality filter or are “personal com m unications.” Code Species Aquatic—Saltwater—Chronic AWQC μ g/L

. Code Species Aquatic—Saltwater—Acute AWQC μ g/L Code Species

A-41Pollutant: DCPA mono-acid degradate CAS: 887547 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000 [ C alifornia] , USEPA 1995[ Great Lakes] ). Carcinogen flag Y/N
RfD m g /kg-day Code BCF L/kg BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L no ASTER data. Code Species Aquatic—Freshwater—Acute AWQC μ g/L no ASTER data. Code Species Aquatic—Saltwater—Chronic AWQC μ g/L no ASTER data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L no ASTER data. Code Species

A-42Pollutant: DCPA di-acid degradate CAS: 2136790 Variable Units Value Source Human Health q1* m g /kg-day No data (IRIS, USEPA Region RBC Table, ATSDR toxicological profiles, USEPA 2000 [ C alifornia] , USEPA 1995[ Great Lakes] ). Carcinogen flag Y/N
RfD m g /kg-day Code BCF L/kg 179 ASTER, 2005. Ref. 7. Veith, GD and P Kosian. Estim ating Bioconcentration Potential from Octanol/Water Partition Coefficients. In D. Mackay et al. (Eds.) Phy s ical behavior of PCBs in the Great Lakes. Ann Arbor Scie. Publ. Ann Arbor, MI:269-282. BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 1364 ASTER, 2005. Ref: 15823. Veith GD, DJ Call, and LT Brooke. Structure-Toxicity Relationships for the Fathead Minnow, Pim e phales prom elas: Narcotic Industrial Chem icals. Can. J. Fish. Aquat. Scie. 40(6):743-748. 1983. Code Es tim ated F r om Acute Value Using Acute-Chronic Ratio of 10; See U.S. EPA. Technical Support Document for W a ter Quality -based Toxics Control. EPA 505/2­ 90-001. March 1991. Species Fathead Minnow Aquatic—Freshwater—Acute AWQC μ g/L 13644 ASTER, 2005. Ref: 15823. Veith GD, DJ Call, and LT Brooke. Structure-Toxicity Relationships for the Fathead Minnow, Pim e phales prom elas: Narcotic Industrial Chem icals. Can. J. Fish. Aquat. Scie. 40(6):743-748. 1983. Code 96-hr LC 50 Species Fathead Minnow
Aquatic—Saltwater—Chronic AWQC μ g/L no ASTER data. Code Species Aquatic—Saltwater—Acute AWQC μ g/L no ASTER data. Code Species

A-43Pollutant: Nicotine CAS: 54115 Variable Units Value Source Human Health q1* m g /kg-day none identified Carcinogen flag Y/N RfD m g /kg-day none identified Code BCF L/kg 4 ASTER, 2005. Ref. 7. Veith, G.D. and Kosian. Estim ating Bioconcentration Potential from Octanol/Water Partition Coefficients. In D. Mackay et. al. (Eds.), Phy s ical Behavior of PCBs in the Great Lakes. Ann Arbor Sci. Publ., Ann Arbor, MI:269-282. 1983. (QSAR.) BAF RSC Aquatic—Freshwater—Chronic AWQC μ g/L 3490 ASTER, 2005. Ref. 16362. Passino-Reader, DR, WH Berlin, and JP Hickey . Chronic Bioassay s of Rainbow Trout Fry with Com pounds Representative of Contam inants in Great Lakes Fish. J. Great Lakes Res. 21(3):373-383. 1995. Geom etric average of LOEC=4200 and NOEC=2900. Code MATC Species Rainbow Trout

Aquatic—Freshwater—Acute AWQC μ g/L Code Species Aquatic—Saltwater—Chronic AWQC μ g/L Code Species Aquatic—Saltwater—Acute AWQC μ g/L Code Species

A-44