TABLE OF CONTENTS

TERBUTHYLAZINE : PRODUCT CHEMISTRY/ ENVIRONMENTAL
FATE AND ECO-EFFECTS SCOPING DOCUMENT PAGE
No.

TERBUTYL AZINE............................................
2

APPENDICES--------------------------------

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2REGISTRATION REVIEW DOCUMENT

PRODUCT CHEMISTRY, ENVIRONMENTAL FATE AND
ECOLOGICAL EFFECTS SUMMARY FOR TERBUTYLAZINE

PCCode: 080814 Case No. 2645

Chemical name Use patterns/use sites
AMA-204 Recirculating cooling
towers/ornamental fountains
Bellacide 325 Recirculating cooling towers
Bellacide 320 Recirculating cooling towers
Bellacide 329 Recirculating cooling towers

Regulatory History

As an herbicide Terbuthylazine was first registered in 1975. For its uses on or in corn fodder, and forage, corn grain (popcor n grain included), sorghum forage and grain, tolerances were established earlier; however since no herbicidal uses were registered,
these tolerances were rev oked in 1992.This document only addresses the antimicrobial
uses of this chemical Antimicrobial uses of algaecide, microbiocide/ microbiostats as end-use formulations of Terbuthylazine were registered in 1986. At present four products containing Terbuthylazine are registered to a total of 2 companies.

Table 1: Registered Active Products for TurbuthylAzine

EPA Reg.
Number Product Name Formulation Type % Active Ingredient Registrant

83451-7 Bellacide 320 MUP 96 BWA Water Additives US, LLC

9386-34 AMA-204 Aqueous Dispersion 4.0 Kemira Chemicals, Inc

83451-8 Bellacide 329 Aqueous Dispersion 44.7 BWA Water Additives US, LLC
83451-9 Bellacide 325 Aqueous Dispersion 4.0 BWA Water Additives US, LLC

3Table 2. Chemical Identity

Common Name Terbuthylazine

Chemical Name 6-chloro-N-(1,1-dime thylethyl)-N-ethyl)-1,3,5-triazine 2,4-dimamine

IUPAC 6-chloro-N-(1,1-dimethyl ethyl)-N-ethyl)-1,3,5-triazine 2,4-dimamine Molecular Weight 229.71

PC Code 80814 CAS Registry Number 5915-41-3

Molecular Formula C 9 H 16 ClN 5 Registration Review Case No. 2645
Registration Review Case Name Terbuthylazine

Classification: Organic

Structure:

Science Findings:

A few data gaps for each di scipline are noted below.

Product Chemistry Summary

Table 3: Physical and Chemical Properties of Terbuthylazine

Guideline
No. Physical and Chemical Properties Value

830.1550 Product identity and composition Refer to Table 2

830.1600 Description of materials used to produce the product CBI

830.1620 Description of production process CBI

830.1650 Description of formulation process CBI

4Guideline
No. Physical and Chemical Properties Value

830.1670 Discussion of formation of impurities CBI

830.1700 Preliminary analysis CBI

830.1750 Certified limits CBI

830.1800 Enforcement analytical method No data

830.1900 Submittal of samples CBI

830.6302 Color Off-White 1

830.6303 Physical State Powdery, globular solid 1

830.6304 Odor Rancid, putrid 1

830.6313 Stability to sunlight, normal and elevated temperature Not sensitive to metal and metal ions; stable at elevated temperature. Not sensitive to sunlight 1

830.6314 Oxidation/Reduction: Chemical Incompatibility No data

830.6315 Flammability
Flash Point No data

830.6316 Explodability No data

830.6317 Storage Stability Moderate temperature: < 1%/year 1 Tropical temperature:< 1%/year 1

830.6319 Miscibility No data

830.6320 Corrosion Characteristic No data

830.6321 Dielectric breakdown voltage No data

830.7000 pH No data

830.7050 UV/Visible absorption spectra No data

830.7100 Viscosity No data

830.7200 Melting Point 178-179 o C 1

830.7220 Boiling point Not applicable

830.7300 Density/ Bulk density 22.04 lbs/ft 3 1 /1.009 g/cc at 20 o C 2

830.7370 Dissociation Constants in water pK
a is 1.9 ± 0.1 at 21 o C 1

830.7520 Particle size Not applicable

830.7550 Octanol/water partition coefficient (K OW ) (Log K

ow ) 3.21±0.39 1

830.7840 Solubility in water 1.5 ppm in water 1

830-7840 Solubility in organic solvents in g/100
ml Acetone: 4.3 g/100ml; ethanol: 1.5 g/100 ml; toluene: 1.04 g/100 ml; n-octanol: 1.25 g/100 ml; ethylene glycol: 0.236 g/100 ml 1

830.7950 Vapor pressure 5.8 x 10 -7 mm Hg at 25 o C 1

Note: 1) The data in Table 3 are reported from industry data submitted in 1990 (MRID#: 416033-03; 2) Calculated by the present reviewer

Product Chemistry Data Gaps : Table 3 lists the guideline tests that are missing; The Agency is requiring these data to be submitted. Appendix C outlines the data justifications for these missing data.

Environmental Fate and Transport Data Summary: EPA’s Reregistration Eligibility Decision (R ED) on Terbuthylazine was completed in 1992 as it was registered as an herbicide. As an antimicrobial, it is registered for uses in recirculating cooling tower (outdoor use), a nd ornamental fountains (indoor use). Both uses are likely to end up in wastewater streams through down-the-drain process.

5Antimicrobials Division has in its database a number of environmental fate studies that were submitted for the agricultural uses. These studies are not sufficient to conduct an environmental fate and transport risk asse ssment/risk characterization for AD uses. Table 4 provides the environmental fate and transport profile of terbuthylazine. The fate studies were conducted on the MUP (96%) Bellacide 320

Table 4 Environmental Fate and Transport Data

Guideline No. / Study Type Results/Conclusions Reference 835.2120/ Hydrolysis:
Abiotic Half life at pH 5 ~ 73 days; Half life at pH 7 = 205 days; Half life at pH 9 = 194 days
Conclusions: Terbuthylazine is stable and persistent at all three pHs
under abiotic conditions MRID#: 419077-07 Study was accepted

835.2240/ Photodegradation
in water
Abiotic The study was done at pH 7, with radiolabeled (C-14)
Bellacide 320.
Conclusions: Terbuthylazine did not degrade to any noticeable point and can be considered as stable persistent photochemically. This
indicates that Terbuthylazine will not degrade on surface water
bodies under abiotic
conditions MRID#: 419948-01 Study was accepted

835.4300/Aerobic Aquatic
Metabolism
Biotic Under aerobic conditions, in a hydrosoil system, Terbuthylazine has a half life of ~ 39 days
Conclusions: Terbuthylazine is stable in soil, but is not classified as persistent as the half life is < 60 days. MRID#: 427900-01 Study was accepted

835. 4400: Anaerobic Aquatic Metabolism
Biotic Under anaerobic conditions, and in a hydrosol system Terbuthylazine degraded
with a half life of about 69 days MRID#: 431762-01 Study was accepted

6Conclusions : Terbuthylazine is stable under anaerobic condition,
but can be classified as moderately persistent under
anaerobic conditions.

Environmental Fate and Transport Conclusions : Terbuthylazine is persistent under abiotic conditions and al so moderately stable under biotic, aerobic and anaerobic conditions in aquatic systems

Environmental Fate and Transport Data Gaps : The Agency anticipates requiring for the following data sets on environmental fate and transport for terbuthylazine

(835.3110) Ready Biodegradability (835.1110) Activated Sludge Isotherm

Ecological Effects Data Summary:

Terbuthylazine was assessed for eco-effects as an agricultural pesticide and a RED
document was issued in 1992. For its antimicrobi al uses, the acute eco -effects data is not
sufficient to assess risks to estuarine/marine fi sh and mollusk; also no data is available to assess risks to aquatic and terres trial (semi-aquatic) plants. Chronic data is totally absent at the present time. The Agency, therefor e, anticipates requiring additional data to
conduct chronic risk eco-eff ects risk assessment.

Table 5 summarizes the eco-toxicity data that AD has in its database.

Table 5 Eco-Toxicity Data for Terbuthylazine Guideline No/ Study Type Results/Conclusions MRID#
850.1010 Aquatic invertebrate acute toxicity (daphnid) The 48 hour LC 50 = 39.4 mg ai/L
Conclusions: Test materials is slightly toxic to daphnia magna The study did not identify the percent purity of the
test substance. 129595/92180007 Since the study did not identify the percent purity of the test substance, this study is classified as supplemental.

850.1010 Aquatic invertebrate acute toxicity (daphnids) 48 hour LC 50 = 21.2 mg ai/L; NOEL < 10 mg/L
Conclusions: Test material is slightly toxic to daphnia magna; Purity of the test was not specified 159290 Study not accepted as the purity of the substance was not specified

7850.1035 Mysid acute toxicity test (shrimp) 96 hour LC 50 = 0.092 mg
ai/L
NOEL could not be
established due to death at
all doses Purity: 99.24%
Conclusions: The test material is very highly toxic to mysid shrimp 40543701 Study accepted

850. 1075 Fish acute toxicity test (bluegill) 96 hour LC 50 = 7.6 ppm Purity: 98%
Conclusions:
The test material is moderately toxic to bluegill
fish 129593/92180005 Study accepted

850.1075 Fish acute toxicity test (rainbow trout) 96 hour LC 50 = 3.6 ppm Purity: 98%
Conclusions:
The test material is moderately toxic to rainbow

trout 129594/92180006 Study accepted

850.2100 Avian acute oral toxicity test (Mallard Duck) LD 50 > 2510 mg ai/kg bw No overt toxicity symptom was observed; a slight body weight change was observed with the highest dose: 2510 mg/kg
Conclusions: Terbuthylazine practically
non-toxic to mallard ducklings Purity: 99.8% 129142/ 92180002 Study accepted

850.2200 Avian acute dietary toxicity test (Mallard Duck)) LC 50 > 5620 mg/kg (usually expressed as ppm)
A concentration related reduction in body weight gain and feed consumption
was observed
Conclusions: Terbuthylazine is practically non-toxic to mallard ducklings Purity: 99.8% 129143/ 92180004 Study accepted

850.2200 Avian acute dietary toxicity LC 50 > 5620 mg/kg (usually expressed as ppm) 129144/92180003 Study accepted

8test (Bobwhite Quail) 30% mortality at 178 ppm level; 20% mortality at 3160 ppm and 30% mortality at 5620 ppm level
Conclusions: Terbuthylazine is practically non-toxic to
mallard duck Purity: 99.8%

Hazard Conclusions : On the acute basis, the limited da ta available categorize technical grade terbuthylazine as being very highly toxic to estuarine/marine invertebrates, moderately toxic to freshwater fish and slight ly toxic to freshwater invertebrates. Acute toxicity data are not availabl e for estuarine fish and mollusks. Aquatic and terrestrial (semi-aquatic) plant toxicity data are not avai lable. Terbuthylazine is practically nontoxic to birds.

Eco-Effects Data Gaps: (850.1075) Estuarine/marine fish, Acute (850.1055 or 850.1025) Estuarine mollusk, Acute. (850. 4400) Aquatic plant growth (v ascular), Tier II, 4 species (859.5400) Aquatic plant growth (algal), Tier II

Down-the drain (EFAST, version 2.0): For Estimating Surface Water Concentration of Terbuthylazine if disposed off into the down-the-drain from AD Uses

Input Parameters: Production volume: ~ 46,000 kg/year (The Agency has assumed that the production volume of this chemical has not changed since 1995 RED) Release days: 365 days
Wastewater Removal: 7.93 % (EPI Suite, Version 4.00) Bioconcentration Factor (BCF): 18.54 L/Kg (EPI Suite, Version 4.0)

Table 6

Down-the-Drain Outputs
Dilution factor Concentration (μg/L) (50 th percentile):
24.22 0.0425

(10 th percentile) 1.0 1.03

9Note: Table 6 shows that the concentration of terbuthylazine going to the wastewater treatment plant to the receiving (s urface) waters is 0.0425 μg/L at 50 th percentile and 1.03 μg/L at 10 th percentile. These concentrations ar e taken as effective environmental
concentrations in surface water and based on these estimated values, Risk Quotients for acute eco-effects for aquatic organisms are cal culated. Data from Table 5 and six is used.
Results are summarized in Table 7.

Table 7 Estimation of Risk Quotients for Acut e-Eco-Effects of Aquatic Organisms

(Guideline #)/ Organisms LC 50 (in μg/L units) Effective
Environmental
Concentration (EEC); μg/L:
50* 10* *(percentile) RQ = EEC/LC 50

* (percentile)
50 * 10*

850.1010: Aquatic invertebrate (daphnids) 39.4 E3 (48 hr) 0.0425 1.03 1.07E-6 2.6E-5

850.1010: Aquatic invertebrate (daphnids) 21.2 E3 (48 hr) 0.0425 1.03 2E-6 4.8E-5

850.1035: Mysid acute toxicity test (shrimp) 0.092 (96 hours) 0.0425 1.03 0.46 11.19

850.1075: fish acute toxicity(bluegill) 7.6E3 (96 hours) 0.0425 1.03 5.5E-6 1.35E-4

850.1075: fish acute toxicity (rainbow trout) 3.6E3 (96 hours) 0.0425 1.03 1.18E-5 2.8E-4

Table 7 clearly indicates that no adverse ac ute-toxic risks are anticipated for aquatic
invertebrates.

10BIBLIOGRAPHY FOR: PRODUCT CHEM ISTRY, ENVIRONMENTAL FATE AND TRANSPORT, AND ECO-EFFECTS

• Reregistration Eligibility Decision (RED) Terbuthylazine, March, 1995. http://www.epa.gov/pesticides/reregistration/status.htm

* EFAST (Version 2)

11APPENDIX A

DATA JUSTIFICATIONS

ENVIRONMENTAL FATE AND TRANSPORT
For TERBUTHYLAZINE

Guideline Number: 835.1110 Study Title: Activated Sludge Sorption Isotherm Rationale for Requiring the Data The results from activated sludge sorption study woul d allow EPA to assess the distribution of the antimicrobial among the solid, aqueous, and vapor phases of WWTPs. Specifically, this study identifies
those chemicals which sorbs to sludge biomass. Practical Utility of the Data
1. How will the data be used? The data would be used to determine the sorption potential of terbuthylazine to activated sludge
biomass and in biological wastewater treatment systems. 2. How could the data impact th e Agency’s future decision-making? If terbuthylazine is not sorbed or biodegraded then, it would pass through a biological treatment system unaffected and it may contaminate surface and drin king waters and also may have potential adverse
effects to nontarget organisms. 3. What is triggering the need for this data? Studies are needed to conduct environmental fate assessment and to determine the sorption potential of
activated sludge for the removal of specific chemical compounds in biological wastewater treatment
systems.

Guideline Number: 835.3110 Data Requirement: Ready Biodegradability Rationale for Requiring the Data The ready biodegradability study would enable the Agency to determine the likelihood that the antimicrobial pesticide of biodegrading in aquatic environments under aerobic conditions. Practical Utility of the Data

1. How would the data be used?

The results from the data would be used to determ ine the rate and extent of aerobic biodegradation of terbuthylazine when it is released into aquatic environments and would help establish if terbuthylazine is stable or not stable under real environmental conditions.

2. How could the data affect the risk assessment? If the result shows low biodegradability then, terbuthylazine would occur in significant qua ntities in
WWTP effluents (water and biosolids) and in environmen tal compartments (e.g., surface waters) such that potential adverse effects to nontarget organisms, found in such environmental
compartments, may occur. 3. What is triggering the need for this data?
Data are needed to conduct environmental fate assessment an d to determine the ready biodegradability of terbuthylazine

12APPENDIX B

ECOLOGICAL EFFECTS DATA REQUIREMENTS
TERBUTHYLAZINE

Guideline Number: 850.1055 Data Requirement: Acute Marine Bivalve Embryo Larvae Toxicity

Rationale for Requiring the Data As part of a Tier I risk assessment, three aquatic animal species are routinely tested by the agency as indicators of potential toxicity to aquatic life and ecosystem health. These studi es allow the Agency to categorize terbuthylazine as toxic or non-toxic to aquatic animal life and to perform ecological risk assessments. If toxic, additional higher tier tests w ould be needed to refine the risk assessment. An endangered species assessment for endangered or threatened estuarine and marine aquatic fish and invertebrates is not possible without these studies. Resear ch bears out that data for a fish cannot serve as a surrogate for an invertebrate and that shrimp react differently to toxicants th an bi-valves due to their physiology and location in the water column. Also, data for freshwater species cannot serve as surrogate data for estuarine/marine species due to differences in water pH, salt content, and other variables that may
affect the test substance. Practical Utility of the Data
1. How would the data be used?
These studies would be used to evaluate the t oxicity of terbuthylazine to non-target and endangered/threatened aquatic animals in estuarine and marine aquatic ecosystems.
2. How could the data affect the risk assessment? Adverse effects to aquatic animal species in estuarine and marine aquatic ecosystems may result in mitigation to protect species at risk. Mitigation might include reduced label dosages, neutralization of effluents prior to discharge into water, restrictions on use in sensitive ecosystems or where endangered species are present, or other mitigation measures. 3. What is triggering the need for this data? Increased concern from state regulators and the pub lic to evaluate impacts on endangered species and persistence in the environment, since initial registrati on, have triggered the need for these studies. Aquatic animals are critical to the food chain and ecosystem health and productivity.

13Guideline Number: 850.1075 Data Requirement: Acute Fish Toxicity (estuarine/marine) Rationale for Requiring the Data Sport fishing and commercial fishing have a high impact on the United States economy. The acute toxicity tests with estuarine/marine fish are desi gned to measure mortality during short-term (96-h) aquatic exposure to a range of concentrations of the pesticide in water. The preferred test species is
Atlantic silverside ( Menidia menidia ) for salt water. Practical Utility of the Data
1. How will the data be used? Data would be used to determine concentration-response curves and calculate LC50's (with 95% confidence intervals) for 24, 48, 72, and 96 h. Additionally, a NOEC for 96 h is reported. The
results from these studies may also provide information for a concentration-selection rationale for fish early-life stage study (OPPTS 850.1400) and the fish life cycle study (OPPTS 850.1500).

2. How could the data affect the risk assessment? There are many estuarine/marine fish species that are listed as threaten ed and endangered in the United States. Although the Atlantic silverside is the preferred species, the sheepshead minnow is considered a surrogate species to represent all mari ne/estuarine fish species in the risk assessment process. As part of the acute risk assessment for aquatic animals, the lowest EC50 or LC50 for
estuarine/marine fish is used in the RQ equation. An acute RQ > 0. 5 would indicate an acute LOC, defined as the potential for acute risk to non-target organisms which may warrant regulatory action in addition to restricted use classification. An acute RQ > 0.1 would result in an acute restricted use LOC, defined as the potential for acute risk to non-target organisms, which may be mitigated through restricted use classification. An acute RQ > 0.05 would fall under the LOC for acute endangered species. 3. What is triggering the need for this data? Data are needed in order to conduct an ecological risk assessment for the proposed use of terbuthylazine in cooling towers and determine the acute toxicity of terbuthylazine to
estuarine/marine fish.

14Guideline Number: 850.4400 Data Requirement: Aquatic plant growth using floating macrophyte Lemna gibba (Tier I) Rationale for Requiring the Data Aquatic plants are essential components of any healthy ecosystem. Plants provide food, shelter, and oxygen to animal species. Lemna represents floating aquatic macrophytes. As part of a Tier I risk assessment, one freshwater aquatic plant indicator species, ( Lemna gibba or L. minor ), is exposed to a range of concentrations of terbuthylazine in fresh water to measure phytotoxicity. Practical Utility of the Data

1. How would the data be used? This study would be used to evaluate the toxicity of terbuthylazine to non-target plants in aquatic ecosystems. Data from these studies would be used to plot concentration response curves for total frond number, growth rate (as number of fronds per day), and mortality (percentage of dead fronds to total number of fronds). EC05s, EC50s, and EC90s would be calculated from the curves. Tier II (definitive) testing is not required if Tier I testing results in an EC50 greater than 1000 mg/L or less than the analytical detection limit. Tier II tests may also include endpoints such as measurements of chlorophyll pigments, biomass, and more detailed observations of frond appearance (i.e., decrease in size, necrosis, chlorosis, or sinking).

2. How could the data affect the risk assessment? Lemna spp. is used to represent all aquatic plants in the risk assessment pr ocess. Adverse effects to non-target plants in aquatic ecosystems may result in mitigation to protect species at risk. Mitigation might include reduced label dosages, neutralizatio n of effluents prior to discharge into water, restrictions on use in sensitive ecosystems or where endangered species are present, or other mitigation measures. Aquatic plants may be affected where terbuthylazine is used as a bacteriostat or fungicide. If EPA is unable to evaluate the potential risks to aquatic plants associated with the bacteriostat or fungicide uses of terbuthylazine, these risks must be presum ed. As part of the risk assessment for aquaticvascular plants, the lowest EC50 is used in the RQ equation. The LOC for endangered and nonendangered plants is defined as a RQ > 1.
3. What is triggering the need for this data? Data are needed in order to conduct an ecological ri sk assessment for the uses of terbuthylazine as a bacteriostat and fungicide and determine its effects on aquatic plants because they are critical to
ecosystem health and productivity.

15Guideline Number: 850.5400 Study Title: Algal toxicity (Tier II) Rationale for Requiring the Data As part of a Tier I risk assessment, one indicator pl ant species is tested for phytotoxicity. This study
would allow the Agency to categorize terbuthylazine as toxic or non-toxic to plants. If toxic, additional higher tier plant tests would be needed. An endangered species assessment for endangered or threatened plants is not possible without this study. Practical Utility of the Data
1. How will the data be used? This study would be used to evaluate the toxicity of terbuthylazine to non-target plants in terrestrial and aquatic ecosystems. 2. How could the data impact th e Agency’s future decision-making? Adverse effects to non-target plants in terrestrial and aquatic ecosystems may result in mitigation to protect species at risk. Mitigation might include redu ced label dosages, neutrali zation of effluents prior to discharge into water, restrictions on use in sensitive ecosystems or where endangered species are present, or other mitigation measures. 3. What is triggering the need for this data? Increased concern from state regulators and the public to evaluate impacts on WWTP operations, endangered species, and persistence in the environment, sin ce initial registration, have triggered the need for this study. Green algae are critical to ecosy stem health and productivity.

1617 APPENDIX C PRODUCT CHEMISTRY DATA REQUIREMENTS

Guideline Number: 830.1800 Study Title: Enforcement Analytical Method
Guideline Number: 830.6314 Study Title: Oxidation/Reduction: Chemical Incompatibility
Guideline Number: 830.6315 Study Title: Flammability/Flash Point
Guideline Number: 830.6316 Study Title: Explodability
Guideline Number: 830.6319 Study Title: Miscibility
Guideline Number: 830.6320 Study Title: Corrosion Characteristic
Guideline Number: 830.6321 Study Title: Dielectric Breakdown Voltage
Guideline Number: 830. 7000 Study Title: pH
Guideline Number: 830.7050 Study Title: UV/VIS absorption Spectra
Guideline Number: 830.7100 Study Title: Viscosity Rationale for Requiring the Data

Product chemistry requirements are necessary for regi stration of a pesticide. These data provide the complete characterization of a chemical. Practical Utility of the Data

1. What is the value of this study?

These data are needed to support the registration to allow EPA to evaluate the potential of the product
to cause unreasonable adverse effects on man and the environment. The data requirements are intended to generate the data and information necessary to address concerns pertaining to the identity, composition, potential adverse effects and the enviro nmental fate of each product. Product chemistry data requirements are comprised of product identity and composition data along with the physical and chemical characteristics of a pesticide chemical.

2. How will the data be used?

This is basic information about the chemical which ensures chemical identity a nd is used to form the basis for labeling and product safety.

3. How could the data affect the risk assessment? Product chemistry data help in the characterization of the pesticide and some of these characteristics become important parameters in various sections or risk assessment (vapor pressure for exposure, Kow fo r bioaccumulation etc.)