## U.S. EPA

High Production Volume Chemical Challenge Program

Robust Summaries and Test Plan for 2,3
- pyridinedicarboxylic acid (CAS No. 89
- 00
- 9)

Revised Submission



## Submitted by: Exponent, Inc.
1800 

## Diagonal Road, Suite 500 Alexandria, VA 22314

On behalf of:
BASF Corporation 3150 Highway JJ Palmyra, MO 63641

Date of submission:
February 9 , 2011HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

ii Table of Contents

1.0 Executive Summary 1
2.0 Introduction 4 2.1 Overview 4 2.2 Methods for Data Review 4 3.0 Substance Information for 2,3
- Pyridinedicarboxylic Acid 6 3.1 Substance Description 6 3.2 Use and Exposure I nformation 6 4.0 Analog for 2,3
- Pyridinedicarboxylic Acid 8 4.1 EPA Guidance for Use of Analogs 8 4.2 Structural Similarity and Comparison of Data for PDC and EPDC 9 5.0 Data Analysis 11 5.1 Physico

- chemical Properties 11 5.2 Environmental Fate and Pathways 11 5 .3 Ecotoxicity 14 5.4 Health Effects 16
6.0 Conclusions and Recommendations 22
7.0 SIDS Data Matrix 23
8.0 References 25

List of Figures
Figure 1. Structure of 2,3

- pyridinedicarboxylic acid 6 Figure 2. Comparison of structures of PDC and EPDC 9HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

iii List of Tables
Table 1: Testing plan and rationale 3 Table 2. Comparison of physico

- chemical properties of PDC and EPDC 10 Table 3. Environmental fate and pathways information for PDC and EPDC 14 Table 4. Ecotoxicity information for PD C and EPDC 16 Table 5. Health effects information for PDC and EPDC 21HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

1 

## 1.0 Executive Summary

2,3

- pyridinedicarboxylic acid (CAS No. 89

- 00

- 9), also known as PDC or quinolinic acid, is solid , with a molecular weight of 167.12 g/mole. The available data for PDC (measured, estimated, and from references) were supplemented with data on a related chemical, 2,3

- pyridinedicarboxylic acid, 5

- ethyl (CAS No. 102268

- 15

- 5), also known as EPDC, which was used as an analog.

2,3

- Pyridinedicarboxylic acid is an intermediate in the manufacturing process for the herbicide imazapyr

. Potential exposures are thought to be extremely limited, because personal protective equipment is used during process sampling events when any exposure might occur. Environmental exposures are expected to be extremely rare, because any spills would be handled in an appropriate manner to minimize release to the environment (which would already be li mited by the physicochemical properties of PDC).

EQC Level III fugacity modeling predicts that, if released to the environment, PDC is expected to partition primarily to soil (77.0%) and water (22.0%). Vapor

- phase PDC, which is expected to be limited due to its low volatility, will be degraded in the atmosphere by reaction with hydroxyl radicals, with a half

- life of 9.9 days. PDC does contain chromophores that absorb at wavelengths > 290 nm and therefore may be susceptible to direct photolysis by sunligh t. The pKa values of 2.43 and 5.48 indicate that PDC will exist almost entirely in ionic form in the neutral range of pH and this, coupled with a low vapor pressure and high water solubility, indicates that volatilization from water is not expected to be an important fate process. PDC is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions. Because of its low octanol

- water partition coefficient, PDC is not expected to bio accumulate. PDC was found to be readily biodegradable in a test conducted according to OECD Guideline 301B. Biodegradation has also been observed in soil (100% after 8 days) and in aqueous nutrient solutions inoculated with soil (81% in 5 days).HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

2 Based upo n the available data for EPDC and the use of PDC as an intermediate in the production of herbicides, aquatic plants are likely the most sensitive of the three trophic levels used to evaluate ecotoxicity. The toxicity of PDC to aquatic plants was therefore determined in a study conducted with the green alga, Pseudokirchneriella subcapitata , according to OECD Guideline 201. The resulting 72

- h our EC50 for PDC was >100 mg/L. There are no studies available on the toxicity of PDC to fish or invertebrates

. Howev er, b ased upon structure

- activity relationships, PDC is expected to be non

- toxic to aquatic animals (LC50/EC50 well in excess of > 100 mg/L), which is supported by the available data for EPDC (EC50 > 100 mg/L for Daphnia magna ).

There are no reliable data on the acute toxicity of PDC to mammals. The acute mammalian toxicity of EPDC is low based upon the measured oral LD50 for rats (> 5000 mg/kg bw in one study and 4251 mg/kg bw in another study) and the dermal LD50 for rabbits (> 2000 mg/kg bw ). In a micro nucleus test with PDC conducted according to OECD Guideline 474, no clastogenic effects or aneugenic activity were seen in bone marrow cells in vivo . R esults for EPDC were negative (i.e., no response) in the bacterial reverse mutation assay. A combined rep eated

- dose toxicity study with the reproduction/developmental toxicity screen (OECD 422) was performed with PDC. The NOAEL for general sy stemic toxicity was 50 mg/kg bw / day for male rats, based upon impaired body weight and pathological findings in the ga stroint estinal tract, and 250 mg/kg bw / day for female rats based upon pathological findings in the gastrointestinal tract. No effects upon reproductive performance or fertility were observed, resulting in a NOAEL for reprodu ctive toxicity of 1000 mg/kg bw / day. Similarly, there were no effects on the offspring, resulting in a devel opmental NOAEL of 1000 mg/kg bw / day.

The original test plan submitted for PDC in February, 2008 identified several data gaps for HPV elements. This revised test plan incorporates the results of testing conducted since that date by the sponsor to determine the melting point, water solubility, biodegradability, acute toxicity to algae, clastogenicity, repeated dose toxicity, reproductive toxicity, and developmental toxicity. Includin g these new data, the overall conclusions and recommendations are that adequate information exists for all HPV elements for 2,3

- pyridinedicarboxylic acid. T his information is summarized in Table 1

.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

3 Table 1: Testing plan and rationale

CAS #89
- 00 - 9
PDC In formation Available?

OECD Study?

GLP Study? Supporting Information? Estimation Method?

Acceptable? Testing Recommended?

HPV Endpoint Physico

- chemical Properties Melting Point Y Y Y Y N Y N Boiling Point Y N N Y Y Y N Vapor P ressure Y N N Y Y Y N
Partition Coefficient Y N N Y Y Y N Water Solubility Y Y Y Y Y Y N
Environmental Fate
Photo

- Degradation Y N N Y Y Y N Water Stability Y N N Y Y Y N Fugacity Y N N Y Y Y N Biodegradation Y Y Y Y Y Y N Ecotoxicity
96

- Hour Fish Y N N Y N Y N
48

- Hour Invertebrate Y Y Y Y N Y N
96

- Hour Algae Y Y Y Y N Y N
Health Effects
Acute Y N N Y N Y N Genetic Toxicology in vitro Y N N Y N Y N Genetic Toxicology in vivo Y Y Y Y N Y N Repeated Dos e Y Y Y N N Y N Reproductive Y Y Y N N Y N Developmental Y Y Y N N Y NHPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

4 

## 2.0 Introduction
2.1 Overview

Exponent, on behalf of BASF Corporation, has prepared the revised robust summaries and revised test plan for 2,3

- pyridinedicarboxylic acid, also ref erred to as PDC or quinolinic acid (CAS No. 89

- 00

- 9), under the United States Environmental Protection Agency’s (U.S. EPA) Extended High Production Volume (eHPV) Chemical Challenge Program.

The purpose of this plan is to develop physicochemical data, envi ronmental fate and effects data, and mammalian health effects data for 2,3

- pyridinedicarboxylic acid consistent with the Screening Information Data Set (SIDS). Therefore, this plan summarizes the existing SIDS data for 2,3

- pyridinedicarboxylic acid and ev aluates the need for testing to fill any data gaps in the SIDS endpoints.



### 2.2 Methods for Data Review

A review of the scientific literature and BASF Corporation’s company data was conducted on the physicochemical properties, environmental fate and effects , and mammalian toxicity endpoints for 2,3

- pyridinedicarboxylic acid and the surrogate, 2,3

- pyridinedicarboxylic acid, 5

- ethyl

- . Searches were conducted on CAS numbers and chemical names using the following databases and web sites: ATSDR, CICAD, ESIS, HPV IS, HERA, IARC, IPCS INTOX Databank, IRIS, Japanese Chemicals Evaluation and Research Institute, NTP, OECD, EFDB, ECOTOX, and TOXNET (including TOXLINE, MEDLINE, CCRIS, HSDB, DART, GENETOX, and CHEMIDPlus). In addition to these databases and web sites, a literature search was performed and standard handbooks (e.g., CRC Handbook on Chemicals, Hawley’s Condensed Chemical Dictionary, Merck Index, etc.) were consulted for physicochemical properties.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

5 This document addresses a single HPV sponsored chemical; how ever, data for a closely related compound, 2,3

- pyridinedicarboxylic acid, 5

- ethyl

- (CAS No. 102268

- 15

- 5) have been used to support the data set for the sponsored chemical through a read

- across approach. Data read

across means that physicochemical property and toxicological data from one chemical are used to estimate those same characteristics for another chemical, and is appropriate only when the two chemicals are deemed sufficiently similar in structure that they are likely to have similar chemical and to xicological properties. Typically, the more data

- based information there is to support this assumption, the stronger the foundation for the read

- across approach will be. The use of structural analogs is consistent with EPA guidance for use of structure

- a ctivity relationships (SAR) in the HPV Chemical Challenge Program (EPA, 1999a).

In accordance with U.S. EPA guidance, in those instances where measured physicochemical parameters and environmental fate data were not available, these properties were develop ed using EPIWIN (EPISuite version4.0) modeling. EPIWIN is an acronym for the Estimation Programs Interface for Microsoft Windows, and is a package of computer programs developed by the U.S. EPA Office of Pollution Prevention and Toxics (OPPTS) , which uses computational methods and structure

- activity relationships (SAR) in estimating chemical properties, environmental fate, and aquatic toxicity of organic chemicals. Because of the inherent limitations of SAR approaches, EPIWIN modeling may produce non

- real istic estimates; therefore, EPIWIN data are evaluated for reasonableness prior to use. In accordance with EPA guidance, environmental transport and fate estimates were developed using the Level III Equilibrium Criteria Model (EQC) in EPIWIN v4.0 as descri bed by Mackay et al. (1996).
Robust summaries were prepared for 2,3

- pyridinedicarboxylic acid and 2,3

- pyridinedicarboxylic acid, 5

- ethyl

- , in EPA’s High Production Volume Information System (HPVIS) for key studies to provide a detailed summary of the test methods and results. Though several studies may have been evaluated for a particular SIDS endpoint, in general robust summaries were prepared only for the critical study that represented the best available data. Selection of the critical study was based on a review of all studies using the ranking system developed by Klimisch et al. (1997), as well as the criteria outlined in the U.S. EPA’s (1999b) methods for determining the adequacy of existing data. Reliable studies that provided supporting data were also included.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

6 

## 3.0 Substance I nformation for 2,3 - P yridinedicarboxylic A cid

3.1 Substance D escription

2,3

- pyridinedicarboxylic acid (CAS No. 89

- 00

- 9 ) , also known as pyridine

- 2,3

- dicarboxylic acid or PDC, is used by BASF to manufacture the herbicide im azapyr. Other uses are as an intermediate in the production of nicotinic acid (HSDB , 2007)

. It is an odorless solid with a molecular weight of 167.12 g/mole. Also known as quinolinic acid, this compound can also be produced as an endogenous metabolite of L

- tryptophan via the kynurenine pathway in the mammalian central nervous system (HSDB, 20 07 ).

Figure 1. Structure of 2,3 - pyridinedicarboxylic acid



### 3.2 Use and Exposure Information

PDC is used in the manufacture of the herbicide imazapyr. The produc tion volume of PDC is greater than 1 million pounds per year; hence PDC is an HPV chemical. The greatest possibility for exposure to workers in the manufacturing process of PDC occurs during the solid charging operation. In order to minimize exposure, op erators involved in this manufacturing step wear aHPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

7 full face organic vapor respirator that includes a dust cartridge, as well as dermal protection. All subsequent processing occurs in closed systems with no routine exposure possible except for QC sampling

. All sampling is performed with the proper personal protective equipment (PPE) , using sample stations designed to minimize the possibility of exposure. S amples are handled in lab oratory settings according to a chemical hygiene plan and using engineering controls such as fume hoods. PDC is not volatile, so the probability of inhalation exposure is quite low and air monitoring is not warranted. Dermal exposures that might be associated with sampling the materials ( and waste streams) during the manufactur ing process are prevented through worker training regarding proper health and safety procedures , the use of proper PPE, and engineering controls.

The vast majority of PDC is conv erted to the herbicide imazapyr, and the inventory of PDC on site for manufac turing at any one time is small. Larger amounts are stored in warehouses. Any small amount of PDC that might end up in the final product is regulated by the active ingredient registration. All organic and aqueous waste streams from the process that use PDC are incinerated on site or disposed of via an on

- site deep well

. Potential environmental exposures are limited to transportation accidents en route to the manufacturing site s or spills on such site s , which are handled in accordance with recognized eme rgency response and safety procedures, respectively, to minimize potential exposures . Should a spill occur, the dispersion of PDC would be minimal. As PDC is a solid, a rainfall event would be needed to mobilize the material such that it would dissolve i nto water or bind to soil. The use of secondary containment at the manufacturing site s further limits potential environmental release

. In summary, PDC poses a minimal exposure threat to workers and the environment.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

8 

## 4.0 Analog for 2,3 - Pyridinedicarboxyli c Acid

4.1 EPA Guidance for Use of Analo gs

In its SAR guidance for the HPV Chemical Challenge Program, the EPA states that the most likely analogs for an HPV chemical are those that resemble the candidate chemical in terms of the following:

1. molecule struct ure/size;
2. some substructure that may play a critical functional role;
3. some molecular property (e.g., lipophilicity, electronic and steric parameters); and/or
4. some precursor, metabolite, or breakdown product.
In general, valid analogs should have close st ructural similarity and the same functional groups as the HPV chemical. In addition, a high correlation is desired between the HPV chemical and the putative analog for the following parameters:

 Physicochemical properties (e.g., physical state, molecular we ight, log K ow , water solubility);  Absorption potential;  Mechanism of action of biological activity; and
 Metabolic pathways/kinetics of metabolism.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

9 

### 4.2 Structural S imilarity and C omparison of D ata for PDC and EPDC

The selected analog for PDC is 2, 3

- pyridine dicarboxylic acid, 5

- ethyl

- . Also known as 5

- ethylpyridine

- 2,3

- dicarboxylic acid, or EPDC, this compound differs from the HPV chemical by only the addition of an ethyl group, and thus is believed to possess most of the desired properties for an a nalog as d escribed in EPA guidance. The structures of the two chemicals are shown in Figure 2.

2,3

- pyridinedicarboxylic acid 2,3

- pyridinedicarboxylic acid, 5

- ethyl

Figure 2. Comparison of structures of PDC and EPDC

Table 2 compares the properties of PDC and E PDC. The source of the information is classified as “measured”, “reference”, or “estimated.” Measured data were obtained through experimental procedures, while estimated data were obtained through structure

- activity correlations (EPIWIN). The designation o f reference means that the values were obtained from handbooks (such as the Merck Index), from material safety data sheets, or from other sources such as databases. Complete details on the sources of information for each data element are provided in the Ro bust Summaries submitted with this Test Plan.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

10 Table 2. Comparison of physico
- chemical properties of PDC and EPDC
Substance Information and Properties 2,3
- pyridinedicarboxylic acid (89
- 00
- 9) 2,3
- pyridinedicarboxylic acid, 5
- ethyl
- (102268
- 15
- 5)

Synonym pyridine

- 2,3

- dicarboxylic acid; PDC; quinolinic acid 5

- ethylpyridine

- 2,3

- dicarboxylic acid; EPDC

Molecular Formula C 7 H 5 NO 4 C 9 H 9 NO 4 Molecular weight 167.12 195.18
Melting point 185

– 190oC (measured) 1 157 ° C (estimated)
Boiling point 357 ° C (estimated ) 380 ° C (estimated)
Vapor pressure 2.6 x 10 - 6 hPa (estimated) 1.5 x 10 - 6 h Pa ( estimated )
Water solubility 9.56 g/L (measured) 2 7.5 g/L (estimated)

Partition coefficient (log Kow) - 0.12 (estimated) 0.92 ( estimated)

Note: estimated values are from EPI WIN
1 Drew, 2008a
2 Drew, 2008b

These compounds have very similar physico

- chemical properties and would be expected to have very similar environmental fate patterns. The absorption, distribution, metabolism, and elimination of these compounds are also expected to be similar. The additional ethyl group on EPDC is not expected to have any effect upon either aquatic or mammalian toxicity , and thus the available toxicity data for EPDC should have a high predictability for PDC. Therefore, data read

- across is used for those instances where valid and reliable data are available for EPDC but not PDC.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

11 

## 5.0 Data Analysis
A summary of the available data for PDC and EPDC is shown , along with information on the reliability of the data, in the completed SIDS data m atrix provided in Section 7. These data are discussed below, while details are provided in the Robust Summaries submitted concurrently with this Test Plan.



### 5.1 Physico - chemical P roperties

BASF conducted testing to determine the melting point and water so lubility of PDC. Melting point is a key property that is used in estimation of other properties, while water solubility is a key property because of its potential relevance for human and environmental risk assessment. In a study conducted according to OECD Guideline 102, the melting point of PDC was determined to be 185

– 190 ° C (Drew, 2008a). The water solubility was determined to be 9.56 g/L at 22 ° C in a study conducted according to OECD Guideline 105 (Drew, 2008b). The remaining data values for physico

- c hemical properties for PDC and EPDC were obtained from literature references, Material Safety Data Sheets (MSDS), and estimation using EPIWIN. These data are presented in Table 2 (in the previous section) and in the Robust Summaries.

Recommendation: No a dditional physico

- chemical properties studies are necessary. The available d ata fill the HPV required data elements with sufficient precision to define the potential hazards of PDC.



### 5.2 Environmental F ate and P athways

The environmental fate data for 2,3

- py ridinedicarboxylic acid and 2,3

- pyridinedicarboxylic acid, 5

- ethyl, are summarized in Table 3, below, along with identification of the sources ofHPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

12 information (reference, measured, or estimated). Additional information is tabulated in Section 7 and more ful ly described in the Robust Summaries.

5.2.1 Photodegradation, V olatilization, and H ydrolysis
Indirect photodegradation in air was calculated for PDC and EPDC using AOPWIN v1.92 . The resulting half

- life was approximately 10 days for PDC and 5 days for EPDC . PDC does contain chromophores that absorb at wavelengths > 290 nm and therefore may be susceptible to direct photolysis by sunlight (HSDB , 2007). The pKa values of 2.43 and 5.48 indicate that PDC will exist almost entirely in ionic form at pH values fro m 5 to 9 , and therefore volatilization from water is not expected to be an important fate process. In addition, the predicted Henry’s Law Constant for PDC is 4.46 x 10 - 1 1 atm

- m 3 /mole (HENRYWIN v3.20), which is extremely low and indicates a lack of volatili ty. Volatilization from soil was minimal in a study by Sims and Sommers (1985). Neither PDC nor EPDC is expected to undergo hydrolysis in the environment because of the lack of functional groups that hydrolyze under environmental conditions.

5.2.2 Bio accumulation, F ugacity, and B iodegradation

Neither PDC nor EPDC is expected to bioaccumulate, as their log Kow values are calculated to be less than 1. If released to the environment, PDC is expected to partition primarily to soil (77%) and water (23%), a s predicted by EQC Level III fugacity modeling. The behavior of EPDC is predicted to be quite similar (84% soil, 16% water).

A study to determine the biodegradability of PDC in the carbon dioxide evolution test (OECD Guideline 301B) was performed, follow ing Good Laboratory Practices (GLP) by Schwarz (2009). The test substance, mixed with a defined inorganic medium and a non pre

- adapted inoculum of activated sludge, was incubated under aerobic conditions for up to 28 days. The resulting mean (2 assays) pr oduction of carbon dioxide was 80

- 90% relative to the theoretical carbon dioxide after 10 days, indicating that PDC was readily biodegradable under the conditions of the test. Studies are also available from the literature in which PDC was demonstrated toHPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

13 biodegrade. Sims and Sommers (1985) investigated the fate of 25 pyridine derivatives in soil, and concluded that pyridinecarboxylic acids were the most labile. Only 3.8% of 2,3

- pyridinedicarboxylic acid remained after 2 days of incubation, and none was de tect ed after 8 days. In aqueous nutrient solutions inoculated with soil, Sims and Sommers (1986) observed 81% biodegradation of PDC within 5 days (based upon the release of inorganic nitrogen) while Naik et al. (1972) observed complete aerobic decompositio n wi thin 4

– 8 days and an aerobic decomposition within 16

– 32 days when tested in enriched cultures containing garden soil.

The ready biodegradability of EPDC was determined according to OECD Guideline 301A, DOC Die

- Away Test performed under GLP by Schwarz (2007). The test substance, mixed with inorganic medium and a non

- adapted inoculum (municipal activated sludge) demonstrated less than 10% biodegradation after 28 days, as measured by dissolved organic carbon. This result indicates that EPDC was not read ily biodegradable under the conditions of the test.

Recommendation: No additional studies on environmental fate and pathways are necessary. The HPV required endpoints are fulfilled by a combination of test results and estimation using acceptable method s.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

14 Table 3

. Environmental f ate and p athways i nformation for PDC and EPDC

Environmental Fate Endpoint 2,3
- pyridinedicarboxylic acid (89
- 00
- 9) 2,3
- pyridinedicarboxylic acid, 5
- ethyl
- (102268
- 15
- 5)
Photodegradation half

- life 9.9 days (estimated) 1 4.8 days (estimated) 1
Hydrolysis Expected to be stable to hydrolysis Expected to be stable to hydrolysis
Fugacity (percent distribution over time assuming equal emissions to air, water and soil) Air: <1%; Water: 22.9%; Soil: 77.0%; Sediment: <1% (estimated) 2 Air: <1%; Water: 16.3%; Soil: 83.6%; Sediment: <1% (estimated) 2

Biodegradation Readily biodegradable per OECD 301B.
(Guideline study, reliable without restriction) 3 Not readily degradable per OECD 301A.
(Guideline study, reliable without restriction) 4

1 es timated by AOPWIN v1.92 2 estimated by EQC Level III 3 Schwarz, 2009 4 Schwarz 2007


### 5 .3 Ecotoxicity

The acute toxicity data are summarized in Table 4 and Section 7 and are fully described in the Robust Summaries. Because PDC is an intermediate in the prod uction of an herbicide (imazapyr), it would be expected that algae would be the most sensitive aquatic organis ms relative to fish and inverte brates. Therefore, an algal toxicity test was conducted according to OECD Guideline 201 and under GLP (Hoffman, 20 09). In this study, the green alga Pseudokirchneriella subcapitata (formerly known as Selenastrum capricornutum ) was exposed for 72 hours to five concentrations of PDC (10 to 100 mg/L in algal medium) , which were analytically verified to be within an aver age of 99.7% of nominal at test initiation and 102.5% of nominal at test termination. The EC50 was calculated based upon both growth rate (increase in biomass per day) and yield ( final biomass minus initial biomass ) and was >100 mg/L for either parameter, indicating that PDC is practically non

- toxic to algae 1

.

1 Ecotoxicity categories are according to http://www.epa.gov/oppefed1/ecorisk_ders/toera_analysis_eco.htmHPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

15 The toxicity of EPDC to two aquatic plant species was determined through studies conducted under GLP according to current guidelines. Analytical verification of the test concentrations was performed

. The results of these tests indicate that EPDC is slightly toxic to the green alga, Selenastrum capricornutum (96

- h our EC50 = 10.8 mg/L; Olivieri, 2000a) and practically non

toxic to the aquatic vascular plant Lemna gibba (14

- day EC50 > 101 mg/L; Olivier i, 2000b). In comparison to the EC50 for green algae for PDC, it is noted th at the former EC50 is from a 72

- hour exposure while the value for EPDC is from a 96

- hour exposure and would be expected to be lower.
No test results are available for fish or dap hnids for PDC; however predictions made using ECOSAR v1.00 indicate that PDC is practically non

- toxic to fish and daphnids , with estimated LC50/EC50 values of 920 mg/L and 3562 mg/L. A reliable acute toxicity test was conducted with EPDC using Daphnia mag na (Mulligan, 2000) according to current guidelines, with analytical verification of the concentrations of test substance, and under GLP. The results indicate that EPDC is practically non

- toxic to D

. magna (48

- h our EC50 > 100 mg/L). ECOSAR predicts that EPDC is not toxic to fish with an estimated LC50 of 220 mg/L.

Recommendation: No additional ecotoxicity studies are necessary. The required HPV endpoints are fulfilled via a combination of test data, estimation, and read

- across from the endpoint informa tion for EPDC. As indicated in Table 4, PDC has similar or less toxicity than the analog, EPDC.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

16 Table 4

. Ecotoxicity i nformation for PDC and EPDC

Ecotoxicity Endpoint 1 2,3
- pyridinedicarboxylic acid (89
- 00
- 9) 2,3
- pyridinedicarboxylic acid, 5
- ethyl
- (10226 8
- 15
- 5)
Acute fish LC50, 96

- h our (mg/L) 920 (estimated) 1 220 (estimated) 1

Acute invertebrate EC50, 48

- h our (mg/L) 3562 (estimated) 1 > 100 for Daphnia magna (measured) 3
(Guideline study, reliable without restriction)

Algal inhibition EC50, 72

- hour (mg /L) > 100 for Pseudokirch n eriella subcapitata (measured) 2
(Guideline study, reliable without restriction) 10.8 for Selenastrum capricornutum (96

- h our exposure) (measured) 4
(Guideline study, reliable without restriction)

Aquatic vascular plant inhibitio n EC50, 14

- day (mg/L) No data; however, not a SIDS endpoint > 101 for Lemna gibba (measured) 5
(Guideline study, reliable without restriction)

1 estimated by ECOSAR 2 Hoffman, 2009 3 Mulligan , 2000 4 Olivieri , 2000a 5 Olivieri , 2000b 

### 5.4 Health E ffects

5.4.1 Absorption, Distribution, Metabolis m and E xcretion PDC (quinolinic acid) can be produced as an endogenous metabolite of the amino acid L

tryptophan via the kynurenine pathway in the mammalian central nervous system. This pathway of tryptophan metabolism pr oduces L

- kynurenine , which can change to the neuroprotective agent kynurenic acid or the neurotoxic agent quinolinic acid. Quinolinic acid can act as a brain excitotoxin when produced and released by activated macrophages and microglia. A high ratio of qui nolinic acid/kynurenic acid has been implicated in a variety of inflammatory neurological diseases in which excitotoxic cell death is found, e.g. , AIDS

- related dementia, Huntingdon’s disease, and Alzheimer’s disease (HSDB, 2007).HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

17 5.4.2 Acute T oxicity

Th e only acute toxicity data available for PDC are from a Material Safety Data Sheet (MSDS, Science Lab.com), which indicates a rat oral LD50 > 500 mg/kg and a rabbit dermal LD50 > 200 mg/kg. Results of studies conducted according to acceptable guidelines an d under GLP are available for EPDC, however. These data indicate that EPDC is practically non

- toxic. In a limit
te st, the rat oral LD50 value was >5000 mg/kg bw for both males and females (Lowe, 1999). In a study using four doses from 1250 to 7500 mg/kg bw , the oral LD50 for the rat was determined to be 4251 mg/kg bw for both sexes combined (Fischer, 1985). Because the study by Fischer (1985) used four doses and identified the LD50, this is considered the key study for acute toxicity. A limit test conducte d with rabbits determined the dermal LD50 to be 2000 mg/kg bw (Fischer, 1985). These data are presented in Table 5.

5.4.3 Repeated dose toxicity
A combined repeated dose toxicity study with the reproduction/developmental toxicity screening test (OECD Guid eline 422) was conducted with PDC, under GLP (Buesen et al., 2010). Parental (F0) male and female Wistar rats (10 per sex per dose) were expose d to 50, 250, and 1000 mg/kg bw

- day of the test substance via daily oral gavage. The vehicle control was 1% carb oxy
methylcellulose. The duration of treatment was 31

– 56 days, cover ing a 2

- week pre

- mating and mating period in both sexes, approximately 1 week post

- mating in males, and the entire gestation period as well as 4 days of lactation in females followed by a n additional treatment until one day before sacrifice.

Cageside examinations were conducted at least daily for any abnormalities. Generally, food consumption and body weight w ere measured once a week. Detailed clinical observations were performed prior to administration and weekly thereafter. Clinicochemical and hematological examinations and urinalyses were performed in 5 F0 parental animals of e ach sex and group toward the end of the administration period. At the end of the administration period a func tional observational battery was performed and motor activity was measured in 5 F0 parental males andHPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

18 females per test group. At the end of the study (males: study day 31, females: study days 53 and 56), the animals were sacrificed after a fasting period. The following organs were weighed: liver, kidneys, adrenal glands, testes, epididymides, prostate, seminal vesicles including coagulation glands, ovaries, uterus, thymus, spleen, brain, heart, and thyroid glands (with parathyroids). For at least the veh icle control and high dose groups, histopathological examinations were made on these organs plus the following: trachea, lungs, spinal cord, sciatic nerve, lymph nodes, stomach, intestines, bladder, and bone marrow. All gross lesions were examined.

N o te st

- substance related, relevant findings were observed at the 50 mg/kg bw / day dose level. At the 250 mg/kg bw / day level, the only effect observed was m inimal desquamation of cecal epithelium in 4 out of 10 males. At the 1000 mg/kg bw / d ay dose, decreased f ood consumption and body weight loss in males was seen during the first study week, and significantly lower mean body weight during study weeks 1

- 3

. M inimal to mild desquamation of cecal epithelium in 7 males, minimal to moderate increase in apoptotic cel l numbe rs of the cecal epithelium in 5 males and 7 females, and minimal to moderate increase in star ry sky cells in the thymus of 3 males and 2 females were observed upon pathological examinations

.

The NOAEL for general, systemic toxicity of PDC was 50 mg/ kg bw / d ay for the male F0 parental animals based on impaired body weight data as well as pathological findings in the gastrointestinal tract , and 250 mg/kg bw / d ay for the female F0 parental animals based on pathological findings in the gastrointestinal tra ct.

5.4.4 Genetic toxicity
PDC was tested for its ability to induce chromosomal damage (clastogenicity) and spindle poison effects (aneugenic activity) in NMRI mice using the micronucleus test method (OECD Guideline 474) in a GLP

- compliant study (Schulz an d Lansiedel, 2008). The test substance, suspended in corn oil, was administered twice orally (24 hours apart) to male animals at dose levels of 500, 1,000 and 2,000 mg/kg body weight. The vehicle control was corn oil. After sacrifice at 24HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

19 hours followin g the last administration, the bone marrow was prepared and examined. The vehicle control demonstrated frequencies of micronucleated polychromatic erythrocytes within the historical control range, while the positive control substances provided the expected results. PDC did not cause any increase in the number of polychromatic erythrocytes containing either large or small micronuclei. No inhibition of erthyropoiesis based on the ratio of polychromatic to normochromatic erythrocytes was detected. Thus, PDC did not demonstrate any clastogenic effect or aneugenic activity in bone marrow cells in vivo

.

Bacterial reverse mutation tests were conducted under GLP with EPDC using five strains of S. typhimurium (TA98, TA100, TA1535, TA1537, TA1538) and E coli WP2uv rA

- , both with and without activation. No mutagenic activity was observed (Bennett, 1986).

5.4.5 Reproductive and Developmental Tox icity
As described in Section 5.4.3, a combined repeated dose toxicity study with the repro

duction/developmental toxicity screening test (OECD Guideline 422) was conducted with PDC, under GLP (Buesen et al., 2010). Parental (F0) male and female Wistar rats (10 per sex per dose) were exposed to 50, 250, and 1000 mg/kg bw / day of the test substance via daily oral gavage. The v ehicle control was 1% carboxymethylcellulose. F 0 animals were mated 13 days after the beginning of treatment to produce litter (F1 generation pups). Mating pairs were from the same dose group. Mating was discontinued as soon as sperm was detected in the vaginal smear. In the reproductive portion of this study, F0 animals were examined for their reproductive performance including determination of the number of implantation sites and the calculation of postimplantation loss for all F0 females. All pups de livered from the F0 parents were examined as soon as possible on the day of birth to determine the total number of liveborn and stillborn pups in each litter, as well as macroscopically evident changes. Pups were examined daily for clinical symptoms. Pup b ody weight was determined one day after birth (PND 1) and on PND 4. All surviving pups (sacrificed on PND 4), all stillborn pups and those which died ahead of schedule were examined externally, eviscerated, and th eir organs were assessed macroscopically

.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

20 No treatment

- related effects were observed on any of the following reproductive parameters: male mating index, male fertility index, female mating index, female fertility index, gestation index, mean number of implantation sites, postimplantation loss, or live birth index. No test

substance related effects were seen upon pup number and status at delivery, pup viability, or sex ratio. There were no significant findings of clinical observations or necropsy in the offspring

. Mean pup body weights were in creased in all tested groups on PND 1 and in the mid

- dose group on PND 4. These differences were mainly caused by low pup body weight in the controls and were assessed as spontaneous and without biological relevance

.

Thus, the NOAEL for PDC for reproducti ve performance and fert ility in rats was 1,000 mg/kg bw / day. The NOAEL for developmental toxicity was also 1 ,000 mg/kg bw / day.

5.4.6 Summary of Health Effects Data The SIDS endpoints relative to health effects for PDC and EPDC are summarized in Table 5 an d Section 7 (SIDS Data Matrix), with more detailed information provided in the Robust Summaries submitted with this Test Plan.

Recommendation: No additional testing is necessary on health effects endpoints. Reliable data are available from recent, GLP

- comp liant studies for PDC for the following health effects endpoints: repeated dose toxicity, clastogenicity, reproductive toxicity and developmental toxicity. Reliable data are also available for the analog, EPDC, for acute oral toxicity, acute dermal toxicit y, and mutagenicity. Because of the high degree of structural similarity between the two compounds, these data are sufficient for use in read

- across for the missing data for PDC, especially given the low toxicity and lack of mutagenic effects observed with EPDC.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

21 Table 5

. Health effects inf ormation for PDC and EPDC

Ecotoxicity Endpoint 1 2,3
- pyridinedicarboxylic acid (89
- 00
- 9) 2,3
- pyridinedicarboxylic acid, 5
- ethyl
- (102268
- 15
- 5)

Acute oral LD50 (mg/kg) > 500 (rat) 1 (secondary citation) > 500 0 (rat) 2 (G uideline study, reliable without restriction) 4251 (rat) 3 (Guideline study, reliable without restriction)

Acute dermal LD50 (mg/kg) > 200 (rabbit) 1 (secondary citation) > 2000 (rabbit) 4 (Guideline study, reliable without restriction)

Repeated dose, NOAEL 50 mg/kg bw / day (males); 250 m g/kg bw / day (females) 5 (Guideline study, reliable without restriction) No data

Genetic Toxicity

– in vitro No data Negative in bacterial reverse mutation test 6 (Guideline study, reliable without restriction)

Genetic Toxicit y

– in vivo No clastogenic or aneugenic effects on bone marrow cells 7 (Guideline study, reliable without restriction) No data

R eproductive toxicity , NOAEL 1000 mg/kg bw / day 5 (Guideline study, reliable without restriction) No data

Developmental toxicity , NOAEL 1000 mg/kg bw / day 5 (Guideline study, reliable without restriction) No data

1 Science Lab.com MSDS 2 Lowe, 1999 3 Fischer, 1985 4 Fischer, 1985 5 Buesen et al., 2010 6 Bennett, 1986 7 Schulz and Landsiedel, 2009HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

22 

## 6.0 Conclusions and R ecommendations

The SIDS Level I endpoints for 2,3

- pyridinedicarboxylic acid (PDC) are filled by a combination of measured and estimated data for the chemical. The adequacy of this information is further supported by comparable data for a closely related chemical, 2,3

- py ridinedicarboxylic acid, 5

- ethyl

- (EPDC). Where certain data are not available for PDC, but reliable data exist for EPDC (e.g., toxicity to invertebrates, acute oral and dermal toxicity, and mutagenicity) , information on EPDC is used in a read

- across mann er to fill these data gaps. The use of data for EPDC to fill these data gaps is considered conservative , as EPDC is slightly more toxic than PDC. No additional testing is proposed for PDC.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

23 

## 7.0 SIDS Data Matrix

SIDS Endpoint 2,3

- pyridinedicarboxylic a cid (89

- 00

- 9) Supporting chemical: 2,3

- pyridinedicarboxylic acid, 5

- ethyl

- (102268

- 15

- 5) Value Reference and Reliability 1 Value Comment Physicochemical Melting point 185

- 190°C Drew, 2008a (K1) 157°C EPIWIN (K2) Boiling point 357°C EPIWIN (K2) 3 80°C EPIWIN (K2) Vapor pressure 2.67 x 10 - 6 hPa EPIWIN (K2) 1.5 x 10 - 6 hPa EPIWIN (K2) Partition coefficient (Log Kow)

- 0.12 EPIWIN (K2) 0.92 EPIWIN (K2) Water Solubility 9.56 g/L at 22oC Drew, 2008b (K1) 7.5 g/L EPIWIN (K2) Environmental fate
P hotodegradation (t 1/2 ) 9.9 days (12

- h ou r day) EPIWIN (K2) 4.8 days (12

- h ou r day) EPIWIN (K2) Hydrolysis Stable Stable Fugacity < 1% air, 22.9% water, 77.0% soil, < 1% sediment EQC Level III (K2) < 1% air, 16.3% water, 83.6% soil, < 1% sediment EQC Leve l III (K2)
Biodegradability 80

- 90% biodegradation in 10 days (OECD 301B) Schwarz, 2007 (K1) < 10% biodegradation in 28 days (OECD 301A) Schwarz, 2007 (K1)
Ecotoxicity Acute Fish 96

- h LC50 920 mg/L (estimated) ECOSAR (K2) 220 mg/L ECOSAR (K2) Acute Invertebrate 48

- h EC50 3562 mg/L (estimated) ECOSAR (K2) > 100 mg/L for Daphnia magna Mulligan, 2000 (K1) Algal Inhibition 96

- h EC50 > 100 mg/L Hoffman, 2009 (K1) 10.8 mg/L for Selenastrum capricornutum Olivieri, 2000a (K1)
Toxicity Acute Oral LD 50 > 500 mg/kg (rat) MSDS (K4) > 5000 mg/kg (rat); 4251 mg/kg (rat) Lowe, 1999 (K1) ; Fischer, 1985 ( K1 ; key study ) Acute Dermal LD50 > 200 mg/kg (rabbit) MSDS (K4) > 2000 mg/kg (rabbit) Fischer, 1985 (K1) Repeated Dose, NOAEL 50 mg/kg bw / day (male); 2 50 mg/kg bw / day (female) Buesen et al., 2010 (K1)HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid

24 SIDS Endpoint 2,3

- pyridinedicarboxylic a cid (89

- 00

- 9) Supporting chemical: 2,3

- pyridinedicarboxylic acid, 5

- ethyl

- (102268

- 15

- 5) Value Reference and Reliability 1 Value Comment Genetic Tox

– In vitro Negative in bacterial reverse mutation test Bennett, 1986 (K1)

Genetic Tox

– In vivo Negative in micronucleus test Schulz and Lansiedel, 2008 (K1) Reproductive Toxicity, NOA EL 1000 mg/kg bw / day Buesen et al

. , 2010 (K1) Developmental Toxicity, NOAEL 1000 mg/kg bw / day Buesen et al., 2010 (K1)

1 Reliability refers to the Klimisch score : K1 = reliable without restriction K2 = r eliable with restriction K3 = not reliable K4 = not assignableHPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid Draft

25 

## 8.0 References

This list of references is for studies as cited in Sections 1 through 7, while a complete list of all data sources reviewed in the development of the Test Plan and Robust Summaries for 2,3

- pyridinedicarboxylic acid can be found in the Robust Summaries.

Buesen, R., Strauss, V., Treumann, S., Fabian, E., van Ravenzwaay, B. 2010. 2,3

- Pyridine Dicarbo x ylic Acid (PDC) Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test in Wista r Rats Oral Administration (Gavage). BASF DocID 2010/1173791. BASF SE, 67056 Ludwigshafen, Germany. Bennett, W.J. 1986. Acute Toxicity and Mutagenicity Testing of CL 271,197. American Cyanamid Company. Drew, M. 2008a. Determination of Melting Point of 2 ,3

- pyridine dicarboxylic acid by OECD Guideline for the Testing of Chemicals #102 Capillary Tube in a Liquid Bath Method. BASF DocID 2008/7009356. BASF Corporation, 26 Davis Drive, Research Triangle Park, NC 27709. Drew, M. 2008b. Determination of Water So lubility of 2,3

- pyridine dicarboxylic acid by OECD Guideline for the Testing of Chemicals #105 Flask Method. BASF DocID 2008/7009357. BASF Corporation, 26 Davis Drive, Research Triangle Park, NC 27709. EPA, 1999a. The use of structure

- activity relationship s (SAR) in the High Production Volume Chemicals Challenge Program. At http://www.epa.gov/chemrtk/sarfinl1.htm

. EPA. 1999b. Determining the adequacy of existing data. A vailable a t : http://www.epa.gov/ch emrtk/pubs/general/datadfin.htm

. Fischer, J.E. 1985. Toxicity Report Data. Animal Industry R/D. Agricultural Research Division. American Cyanamid Co. P.O. Box 400, Princeton, NJ 08540. Report# A85

- 79. Hoffman, F. 2009. Effect of Reg. No. 4036318 (Metaboli te and Intermediate of BAS 693 H, Imazapyr) on the Growth of the Green Alga, Pseudokirchneriella subcapitata . BASF DocID 2009/1011444, BASF SE, BASF Agricultural Center Limburgerhof, Crop Protection Division, Ecology and Environmental Analytics, P.O. Box 1 20, Limburgerhof, Germany. HSDB, Hazardous substances data ban http://toxnet.nlm.nih.gov/cgi

bin/sis/search/f?./temp/~MSAgqg:1

. Last revision 2007

- 10

- 11

. Klimisch, H.J., Andreae, M. And Tillmann, U., 1997. A systematic approach for evaluating the quality of experimental toxicological and ecotoxicological data. Regulatory Toxicol. and Pharmacol. 25:1

- 5.HPV Robust Summaries and Test Plan

– 2,3
- pyridinedicarboxylic acid Draft

26 Lowe, C.A. 1999. Oral LD50 Study in Albino Rats with CL 271197. Toxicology Study Report Number A98

- 100. American Cyanamid Company. Agricultural Products Res earch Division. Toxicology Department. P.O. Box 400. Princeton, NJ 08543

- 0400. Mackay, D., DiGuardo, A., Paterson, S., and Cowan, C. et al. . 1996 . Evaluating the Environmental Fate of a Variety of Types of Chemicals Using the EQC Model. Envir. Toxicol. Che m. 15:1627

- 37. Material Safety Data Sheet. Quinolinic Acid MSDS. Prepared By: Sciencelab.com, Inc. 14025 Smith Rd, Houston, TX 77369. Mulligan, E. 2000. Acute Toxicity of CL 271,197 to Daphnia magna Under Static Test Conditions. American Cyanamid Company. Global Agricultural Products Research Division, Princeton, NJ 08543

- 0400. Performing Laboratory: American Cyanamid Company, Ecotoxicology Laboratory Facility, Global Laboratory Products Research Division. P.O. Box 400, Princeton, NJ 08543

- 0400. Laborator y Project Identification ETX

- 99

- 132. Naik, N.M., Jackson, R.B., Stokes, J., and Swaby, R.J. 1972. Microbial degradation and phytotoxicity of picloram and other substituted pyridines. Soil Biol. Biochem; 4:313

- 323. Olivieri, C.E, Boeri, R.L., Ward, T.R. 200 0a. Effect of CL 271,197 on the Growth of Selenastrum capricornutum . American Cyanamid Company. Report Number ETX

- 99

- 133. Performing Laboratory: T.R. Wilbury Laboratories, Inc. 40 Doaks Lane, Marblehead, MA, 01945, Study No. 1724

- AC. Olivieri, C.E, Boeri, R.L., Ward, T.R. 2000b. Effect of CL 271,197 on the Growth of Lemna gibba G3. American Cyanamid Company. Report Number ETX

- 99

- 131. Performing Laboratory: T.R. Wilbury Laboratories, Inc. 40 Doaks Lane, Marblehead, MA, 01945, Study No. 1725

- AC. Schulz, M. an d Landsiedel, R. 2008. 2,3

- Pyridine Dicarboxylic Acid (PDC) Micronucleus Test in Bone Marrow of the Mouse. BASF DocID 2008/1087535. BASF Corporation, 63461 Missouri, USA. Schwarz, H. 2007. Determination of the Biodegradability in the DOC Die

- Away Test, Re port. BASF Aktiengesellschaft. Experimental Toxicology and Ecology. 67056 Ludwigshafen, Germany. Project No.: 21G0188/063133. Schwarz, H. 2009. 2,3

- Pyridine Dicarboxylic Acid (PDC) Determination of the Biodegradability in the CO2

- Evolution Test. BASF DocID 2009/1009298. BASF Corporation, 63461 Missouri, USA.
Science Lab.com, Quinolinic Acid MSDS

. Sims, G.K., and Sommers , L.E . 1985. Degradation of pyridine derivatives in soil. J. Environ. Qual. 14:580

- 4. Sims, G.K., and Sommers, L.E. 1986. Biodegradation o f pyridine derivatives in soil suspensions. Environmental Toxicology and Chemistry; 5:503

- 509.