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Sodium and Potassium Dimethyldithiocarbamate Salts Registration Review Team

Human Health

Timothy Dole

Steve Malish

Zoё Layton

Environmental Fate and Effects

Srinivas Gowda

James Breithaupt

William Erickson

Siroos Mostaghimi

Risk Management

Sandra O’Neill

Office of General Counsel

Philip Ross
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ABBREVIATIONS AND SYMBOLS

AD Antimicrobials Division

A.I. or a.i. active ingredient

aPAD acute population adjusted dose 

ASRI activated sludge respiration inhibition

atm-m3

/mole atmospheric pressure-cubic meter per mole

BCF bioconcentration factor 

°C degrees Celsius

CaSO4 calcium sulfate

CaSO3 calcium sulfite

CAS Chemical Abstracts Service 

CCA chromated copper arsenate

CFR Code of Federal Regulations 

CHO Chinese hamster ovary

CMA Chemical Manufacturers Association

CO2 carbon dioxide

COC concentration-of-concern

cPAD chronic population adjusted dose 

CS2 carbon disulfide

DCI data call-in

DEA diethanol amine

DMA dimethylamine

DDC dimethyldithiocarbamate

EC50 median (or 50 percent) effect concentration

EC05 5 percent effect concentration

ECOTOX ECOTOXicology

EDI estimated daily intake

EDSP Endocrine Disruptor Screening Program 

E-FAST Exposure and Fate Assessment Screening Tool

EPI Suite Estimation Program Interface Suite

EPA Environmental Protection Agency 

FDA Food and Drug Administration 

FFDCA Federal Food, Drug, and Cosmetic Act

FGD flue-gas desulfurization

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act

FQPA Food Quality Protection Act 

FWP Final Work Plan

g/mol grams per mole

GLN guideline number

HPV high production volume

IDS Incident Data System 

KDDC potassium dimethyldithiocarbamate

Koc organic carbon normalized soil-water partition coefficient

Kd soil-water partition coefficient

Kow octanol-water partition coefficient

LC50 median (or 50 percent) lethal concentration

LD50 median (or 50 percent) lethal dose

LOAEC lowest-observed-adverse-effect-concentration 

LOEC lowest-observed-effect-concentration

LOAEL lowest-observed-adverse-effect-level
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Log Kow logarithm of the octanol-water partition coefficient

μg microgram

ml/g milliliter per gram

mg/kg milligram per kilogram

mg/kg/day milligram per kilogram per day 

mg/L milligram per liter

mm Hg millimeter of mercury

MOE margin of exposure 

MRID Master Record Identification Number

MRL maximum residue limit 

N/A not applicable 

NaDDC sodium dimethyldithiocarbamate salt

nm nanometers

NOAEC no-observed-adverse-effect-concentration

NOAEL no-observed-adverse-effect-level

OCSPP Office of Chemical Safety and Pollution Prevention

OECD Organization for Economic Co-operation and Development

OPP Office of Pesticide Programs

PAD population adjusted dose

PAI pure active ingredient

PDM Probabilistic Dilution Model

% percent

PC Code Pesticide Chemical Code

PCF pounds per cubic foot

pH power of hydrogen or power of the concentration of the hydrogen ion

PHED Pesticide Handler’s Exposure Data

PIS primary irritation score

pKa power of the acid dissociation constant or negative base-10 logarithm of the acid 

dissociation constant of a solution

ppb parts per billion 

ppm parts per million

PWP Preliminary Work Plan

QSAR quantitative structure-activity relationship

RED Reregistration Eligibility Decision

SAR structure activity relationship

SF safety factor

SSTS Section Seven Tracking System

SO2 sulfur dioxide

TEP typical end-use product

TGAI technical grade active ingredient

TMDL total maximum daily loads

TMTDS tetramethylthiuram disulfide (Thiram)

TMTMS tetramethyl thiomonosulfide

TMTU tetramethyl thiourea

UF uncertainty factor

UV/VIS ultraviolet/visible light absorption

% w/w percent weight per weight.

WP wettable powder

WWTPs wastewater treatment plants
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Table of Contents

1 Introduction............................................................................................................................. 7

1.1 Statutory and Regulatory Authority ................................................................................. 7

1.2 Case Overview ................................................................................................................. 9

1.3 Chemical Identification and Properties............................................................................ 9

1.4 Use/Usage Description................................................................................................... 11

1.4.1 Registrations ........................................................................................................... 11

1.4.2 Summary of Registered Uses.................................................................................. 11

1.4.3 Usage Information .................................................................................................. 12

1.5 Regulatory History ......................................................................................................... 12

1.5.1 Recent/Pending Regulatory Actions....................................................................... 13

1.5.2 Tolerance Information ............................................................................................ 13

1.6 Incidents......................................................................................................................... 14

1.6.1 Human Health ......................................................................................................... 14

1.6.2 Ecological ............................................................................................................... 14

2 Anticipated Data Needs ........................................................................................................ 15

3 Human Health Risk Assessment........................................................................................... 19

3.1 Existing Toxicological Endpoints.................................................................................. 19

3.2 Dietary Exposure............................................................................................................ 20

3.2.1 Food ........................................................................................................................ 20

3.2.2 Drinking Water ....................................................................................................... 21

3.3 Occupational and Residential Exposures....................................................................... 21

3.3.1 Occupational Exposures.......................................................................................... 21

3.3.2 Residential Exposures............................................................................................. 23

3.4 Aggregate and Cumulative Exposure............................................................................. 24

3.4.1 Aggregate Exposures.............................................................................................. 24

3.4.2 Cumulative Exposures............................................................................................ 24

4 Environmental Risk Assessment........................................................................................... 24

4.1 Water Quality ................................................................................................................. 24

4.2 Environmental Conceptual Model Exposure Pathways................................................. 25

4.3 Ecological Effects Assessment....................................................................................... 31

4.3.1 Mode of Action....................................................................................................... 31

4.3.2 Measures of Effect (Ecotoxicology Endpoints)...................................................... 31

4.4 Exposure Analysis Plan.................................................................................................. 33

4.4.1 Aquatic and Terrestrial Wildlife Exposure Estimates ............................................ 33

4.4.2 Screening Level Down-the-Drain Analysis............................................................ 33

4.5 Effects Analysis Plan ..................................................................................................... 34

5 Endocrine Disruptor Screening Program (EDSP)................................................................. 34

6 Guidance for Commenters.................................................................................................... 35

6.1 Preliminary Work Plan................................................................................................... 35

6.1.1 Trade Irritants.......................................................................................................... 35

6.1.2 Water Quality.......................................................................................................... 35

6.1.3 Environmental Justice............................................................................................. 35

6.1.4 Structure Activity Relationships............................................................................. 35

6.1.5 Additional Information ........................................................................................... 36

7 Next Steps............................................................................................................................. 37
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8 References............................................................................................................................. 38

Appendix A Toxicology Profile for Dimethyldithiocarbamate ............................................... 43

Appendix B Environmental Fate ............................................................................................. 51

Appendix C Ecotoxicology Profile.......................................................................................... 60

Appendix D Product Chemistry............................................................................................... 69

List of Tables

Table 1 – Summary of Anticipated Risk Assessments and Data Needs: Dimethyldithiocarbamate

......................................................................................................................................................... 8

Table 2 – Anticipated Registration Review Schedule .................................................................... 9

Table 3 – Chemical Identification of Dimethyldithiocarbamate Sodium and Potassium Salts...... 9

Table 4 – Physical-Chemical and Fate Properties for Dimethyldithiocarbamate Salts................ 10

Table 5 – Summary of the Registered Uses of Dimethyldithiocarbamate.................................... 12

Table 6 – Studies Anticipated as Needed for the Registration Review of 

Dimethyldithiocarbamate.............................................................................................................. 15

Table 7 –Toxicological Endpoints Used for the Dimethyldithiocarbamate RED ........................ 19

Table 8 – Occupational Exposure Scenarios for the Dimethyldithiocarbamate Salts.................. 22

Table 9 – Residential Exposure Scenarios for DDC Salts............................................................ 23

List of Figures

Figure 1 – Conceptual Model for Cooling Tower Use of DDC Salts and Ecological Exposure and 

Effects of DDC Salts to Aquatic and Terrestrial Organisms........................................................ 27

Figure 2 - Conceptual Model for Environmental Exposure of DDC Salts from Water System and 

Flue-Gas Desulfurization (FGD) to Aquatic and Terrestrial Organisms...................................... 28

Figure 3 – Conceptual Model for Aquatic (A) and Terrestrial (B) Environmental Exposure of 

DDC Salts in Recovered Water from Oil and Gas Use ................................................................ 29

Figure 4 - Conceptual Model for Aquatic (A) and Terrestrial Environmental Exposure (B) of 

DDC Salts from Use in Oil and Gas Extraction, Drilling Muds/Fluids, Hydraulic Fracturing 

Fluids, and Primary, Secondary, and Tertiary (Enhanced Oil) Fluids.......................................... 30

Figure 5 - Conceptual Model for Aquatic Environmental Exposure of DDC Salts from Use in 

Pressure Treated Wood................................................................................................................. 31
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1 Introduction

This document is the United States Environmental Protection Agency’s (USEPA, EPA or “the 

Agency”) Preliminary Work Plan (PWP) for Sodium and Potassium Dimethyldithiocarbamate 

Salts, herein referred to as dimethyldithiocarbamate or DDC salts. The PWP document explains 

what EPA's Office of Pesticide Programs (OPP) knows about dimethyldithiocarbamate, 

highlighting anticipated data and assessment needs, identifying the types of information that 

would be especially useful to the Agency in conducting the review, and providing an anticipated 

timeline for the dimethyldithiocarbamate review. This PWP document does not include 

disodium ethylene bis dithiocarbamate (Nabam which is also a dimethyldithiocarbamate).

Nabam was included in its own Registration Eligibility Decision (RED) rather than the 2009 

Dimethyldithiocarbamate RED Amendment and is being addressed in a separate Registration 

Review case (docket number EPA-HQ-OPP-2012-0339). Additionally, Nabam produces 

ethylene thio urea (ETU) as a degradate whereas DDC salts do not.

The registration review process was designed to include a public participation component to 

solicit input from interested stakeholders. The Agency intends, by sharing this information in the 

docket, to inform the public of what it knows about dimethyldithiocarbamate and what types of 

new data or other information would be helpful for the Agency to receive as it moves toward a 

decision on dimethyldithiocarbamate. The Agency encourages all interested stakeholders to 

review the PWP and to provide comments and additional information that will help the Agency’s 

decision-making process for this chemical.

1.1 Statutory and Regulatory Authority

The Food Quality Protection Act (FQPA) of 1996 mandated a registration review program. All 

pesticides distributed or sold in the United States generally must be registered by the USEPA

based on scientific data showing that they will not cause unreasonable risks to human health or 

the environment when used as directed on product labeling. The registration review program is 

intended to make sure that, as the ability to assess risk evolves and as policies and practices 

change, all registered pesticides continue to meet the statutory standard of no unreasonable 

adverse effects to human health or the environment. Changes in science, public policy, and 

pesticide use practices will occur over time. Through the registration review program, the 

Agency periodically reevaluates pesticides to make sure that as change occurs, products in the 

marketplace can be used safely. Information on this program is provided at 

http://www.epa.gov/oppsrrd1/registration_review/.

The Agency is implementing the registration review program pursuant to Section 3(g) of the 

Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and will review each registered 

pesticide every 15 years to determine whether it continues to meet the FIFRA standard for 

registration. The regulations governing registration review begin at 40 CFR 155.40. The Agency 

will consider benefits information and data as required by FIFRA. The public phase of 

registration review begins when the initial docket is opened for each case. The docket is the 

Agency’s opportunity to state what it knows about the pesticide and what additional risk analyses 

and data or information it believes are needed to make a registration review decision. After 

reviewing and responding to comments and data received in the docket during this initial 
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comment period, the Agency will develop and commit to a Final Work Plan (FWP) and 

anticipated schedule for the Sodium and Potassium Dimethyldithiocarbamate Salts Case. 

Documents associated with this registration review can be viewed at http://www.regulations.gov

in docket EPA-HQ-OPP-2013-0245. Below is a summary of the issues relevant to this 

registration review case. 

Table 1 – Summary of Anticipated Risk Assessments and Data Needs: 

Dimethyldithiocarbamate

Risk Assessment 

Assessment 

Necessary to 

Support 

Registration 

Review

Date of 

Most 

Recent 

Assessment

Type of 

Assessment 

Required 

(New/Updated)

Data Anticipated as Needed

(See Table 6 for details)

Dietary (food) Yes 7/14/2009 Updated Migration Studies1

Dietary (drinking water) Yes 7/8/2009 Updated None

Occupational and 

Residential Handler Yes 3/3/2009 Updated

Inhalation Toxicity – 90 Day

Reproduction and Fertility Effects

Chronic Toxicity/Carcinogenicity3, 4

Dermal Exposure

Inhalation Exposure

Product Use Information

Residental Post 

Application - Incidental 

Oral and Dermal 

Yes 3/3/2009 Updated Surface Residue Data3

Aggregate Yes N/A New Reproduction and Fertility Effects

Chronic Toxicity/Carcinogenicity3,4

Cumulative No (see 3.4.2) N/A None None 

Tolerance Review (EPA) No (see 1.5.2) 7/14/2009 N/A None

Ecological Effects and 

Environmental Fate

Yes 2009 New2

Updated for 

wood 

preservative

Fish (chronic);

Aquatic invertebrates (chronic); 

Aquatic and semi-aquatic plants;

Beneficial Insect Studies3

Aerobic soil metabolism3

Leaching from treated wood3

Activated Sludge Respiration Inhibition 

or Modified Activated Sludge 

Respiration Inhibition

Ready biodegradability test or one of 

three biodegradation in activated sludge 

simulation tests

1 Residue chemistry data are anticipated to be needed to determine dietary exposure to DDC as a result of food contact with 

components of food packaging such as coatings, adhesives, paper-making additives, and paper made from treated pulp 2 Commercial/Industrial Cooling Water, Pulp/Paper Mill Water Systems, Gas/Oil operations

3 EPA has received a request to cancel the only product with a wood preservative use. When the cancellation order becomes 

effective, this anticipated data requirement should no longer be needed 4 EPA has received a request to cancel the only product with a metal working fluid use. When the cancellation order becomes 

effective, this anticipated data requirement should no longer be needed
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Table 2 – Anticipated Registration Review Schedule

Anticipated Activity Target Date*Completion Date

Phase 1: Opening the Docket 

Open Docket and 60-Day Comment Period for Preliminary Work Plan 2013-09 2013-09-18

Close Public Comment Period 2013-11

Phase 2: Case Development 

Issue Final Work Plan 2014-03

Issue Data Call-In (DCI) 2016-03

Receive Data to be Considered in Risk Assessment 2019-03

Open 30-Day Public Comment Period for Preliminary Risk Assessment(s) 2020-09

Close Public Comment Period 2020-10

Phase 3: Registration Review Decision and Implementation 

Open 60-Day Public Comment Period for Proposed Decision 2021-03

Close Public Comment Period 2021-05

Issue Final Decision 2021-09

Begin Post-Decision Followup 2021

Total (years) 8

*The anticipated schedule will be revised as necessary (e.g., need arising under the Endocrine Disruptor Screening Program with 

respect to the active ingredients in this case).

1.2 Case Overview

The docket for the Sodium and Potassium Dimethyldithiocarbamate Salts Case (Case 8100) has 

been established at http://www.regulations.gov in docket number EPA-HQ-OPP-2013-0245.

1.3 Chemical Identification and Properties

Table 3 presents the active ingredients to be assessed in Case 8100: Sodium 

Dimethyldithiocarbamate Salt (NaDDC, PC Code 034804); and Potassium 

Dimethyldithiocarbamate Salt (KDDC, PC Code 034803). These chemicals are herein referred 

to as dimethyldithiocarbamate or DDC salts. 

Table 3 – Chemical Identification of Dimethyldithiocarbamate Sodium and Potassium Salts

Chemical Name Sodium dimethyldithiocarbamate Potassium dimethyldithiocarbamate

Abbreviation NaDDC KDDC

Classification Dithiocarbamate Dithiocarbamate

PC Code 034804 034803

CAS No. 128-04-1 128-03-0

Molecular Formula C3H6NNaS2 C3H6NKS2

Molecular Weight 143.21 grams per mole 159.31 grams per mole

Purity 40 percent (%) weight per weightA

(w/w) as aqueous solution 50% w/w as aqueous solution
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Chemical Name Sodium dimethyldithiocarbamate Potassium dimethyldithiocarbamate

Molecular Structure

A % w/w is the number of grams of solute per 100 grams of solutions.

NaDDC and KDDC salts product chemistry information (source: MRIDs 41586303, 41609403, 

41651301, 42510401, and 41609407 and EPI Suite v4.1) relevant to risk assessment is 

summarized in Table 4 and details of the environmental fate properties are discussed in 

Appendix B and product chemistry information in Appendix D.

Table 4 – Physical-Chemical and Fate Properties for Dimethyldithiocarbamate Salts

Guideline 

No. 

Physical and Chemical 

Properties NaDDC KDDC

830.7000 pH 

As measured 13.3 at 20 degrees 

Celsius (°C)

10.1 (1% aqueous solution) - HPV

12.6 (32% aqueous solution) - HPV

9-14 (50% solution)

830.7050 Ultraviolet (UV)/Visible 

Absorption 

NaDDC was identified by UV/VIS

spectra recorded at different pH values.

Result at pH < 2:

> 200 nanometers (nm), ε = 0 l mol-1

cm-1

Result at pH 7:

254 nm, ε = 12792 l mol-1 cm-1

279 nm, ε = 13127 l mol-1 cm-1

295 nm, ε = 1863 l mol-1 cm-1

Result at pH > 11:

254 nm, ε = 13388 l mol-1 cm-1

279 nm, ε = 13687 l mol-1 cm-1

295 nm, ε = 1803 l mol-1 cm-1

KDDC was identified by UV/VIS

spectra recorded at different pH values.

Result at pH < 2:

207 nm, ε = 12713 l mol-1 cm-1

Result at pH 7:

253 nm, ε = 26409 l mol-1 cm-1

279 nm, ε = 28187 l mol-1 cm-1

495 nm, ε = 3562 l mol-1 cm-1

Result at pH > 11:

254 nm, ε = 12714 l mol-1 cm-1

279 nm, ε = 13120 l mol-1 cm-1

830.7200 Melting point PAI: > 300 °C with decomposition. PAI: > 300 °C with decomposition.

830.7220 Boiling point Not required since PAI is solid

Boiling point of 32% solution: 102°C

Not required since PAI is solid.

Boiling point of 50% solution: >100°C

830.7300 Density 1.17 g/ml (40% solution) 1.25 g/ml (50% solution)
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Guideline 

No. 

Physical and Chemical 

Properties NaDDC KDDC

830.7370 Dissociation Constant in 

water 

pKa = 5.4 for the organic portion/ 

Estimated/(40% w/w aqueous 

solution).

6.5 x 10-8 at 20°C. Performed on PAI.

pKa value: Not applicable; product 

decomposes below pH 8. – HPV

pKa = 5.4 for the organic portion/ 

Estimated/(40% w/w aqueous 

solution).

6.5 x 10-8 at 20°C. Performed on PAI.

830.7550 Partition coefficient (noctanol/water) 

Performed on PAI. Estimated to be less 

than 1 based on solubility at 20°C.

−2.41 (EPI Suite v4.1)

−1.43 (EPI Suite v4.1)

830.7840 Solubility in water 

Complete

132 g/100 ml of water at 20 °C 

Performed on PAI.

Complete.

Easily soluble in water.

830.7950 Vapor pressure Solid: 4.17 x 10-9 mm Hg at 25°C

(EPI Suite v4.1).

Solid: 8.15 x 10-10 mm Hg at 25°C 

(EPI Suite v4.1).

N/A Henry's Law Constant 7.857 x 10-16 atm-m3

/mole

(EPI Suite v4.1)

2.01 x 10-16 atm-m3/mole

(EPI Suite v4.1).

PAI - Pure active ingredient

HPV – High production volume

1.4 Use/Usage Description

1.4.1 Registrations

There are 18 registered KDDC products and 13 registered NaDDC products. There are no inert uses 

and no pending registrations. 

1.4.2 Summary of Registered Uses

Table 5 presents a summary of the registered uses of DDC salts that will be assessed in this 

registration review. Per label directions, products that contain only DDC salts can be open 

poured or metered into the system being treated or the product being preserved. Some products 

also contain the active ingredient Nabam and these products require closed system loading for 

certain uses such as industrial cooling towers, oil drilling fluids, paper mills, beet sugar mill and 

cane sugar mills. These requirements are based on label specifications in the Nabam RED1.

Several product labels have been amended since the 2009 RED Amendment to voluntarily delete 

uses. Deleted uses include sapstain treatment, paints and coatings, metalworking fluids, cotton 

fabrics, wood veneers and alginate pastes. There are still some labels that include some of these 

uses, and the labels are noted in Table 5.

 1 PC Code 014503, http://www.epa.gov/oppsrrd1/REDs/0641.pdf
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Table 5 – Summary of the Registered Uses of Dimethyldithiocarbamate 

Use Site

Application Rate in 

Terms of Active 

Ingredient (A.I.)

Labels (EPA Registration no.)

Industrial Processes and Water Systems

Air Washer Water Systems 6 to 29 ppm Several labels.

Beet and Cane Sugar Mills 3 ppm Several labels.

Beet Sugar Mills 12 ppm One label (45728-29)

Coal Slurry Systems 75 ppm One label (34688-76)

Commercial/Industrial Cooling Water Systems 6 to 59 ppm Several labels.

Evaporative Condenser Water Systems 6 to 59 ppm Several labels.

Food Processing Water Systems 3 to 12 ppm Several labels.

Oil Recovery Drilling Muds and Packer Fluids 77 to 1214 ppm Several labels.

Oil Recovery Injection Water, Secondary 4 to 394 ppm Several labels.

Pulp and Paper Mill Water Systems 113 to 250 ppm Several labels1

Reverse Osmosis Water Systems 10 to 51 ppm Several labels.

Sewage Systems 5 to 14 ppm Two labels (1448-70, 34688-77)

Material Preservative

Adhesives, Coatings, Emulsions 1000 ppm One label (1022-563)

2

Fuels and Oils Bottom Water 58 ppm One label (1022-563)

2

Metal Working Fluids 1000 ppm One label (1022-563)

2

Paints and varnish (applied film) 1000 ppm One label (1022-563)

2

Papermaking Additives

(Alum solutions, pigment slurries, coating 

formulations etc.)

200 ppm Two labels (1022-5631,2, 1448-70)

Wood Preservative

Wood, Pressure Treatment 1 pound per cubic foot One Label (1022-577)

2

1 Includes indirect food uses. 2

EPA has received a product cancellation request for 1022-563, 1022-577, and 1022-574. A cancellation order is anticipated to be 

issued in late 2013.

1.4.3 Usage Information 

According to the Specialty Biocides North America Report 2004-2005 (Kline, 2006) the 

dithiocarbamates, which include Nabam (disodium ethylene bis dithiocarbamate), and 

dimethyldithiocarbamate, are used primarily for paper production and industrial cooling water 

treatments, and to a lesser extent, for leather production. The report does not distinguish the use 

patterns for Nabam and dimethyldithiocarbamate. With respect to wood preservation, the report 

indicates that dimethyldithiocarbamate is not used.

Production volume data in the EPA Section Seven Tracking System (SSTS) for the years 2004 

through 2008 indicate that no more than 2,000,000 kilograms of dimethyldithiocarbamate are 

sold per year in the United States2

.

1.5 Regulatory History 

The Dimethyldithiocarbamate Salts were previously included in RED Case 2180, with PC Codes 

034801, 034803, 034804, 034805, and 034806. KDDC (034803) and NaDDC (034804) have 

been split from Case 2180 and moved into Case 8100 for registration review; case 8100 consists 

 2 As per EPA’s Section Seven Tracking System, data pulled on 3/12/13.
Page 13 of 70

of only these two chemicals. The Agency completed an Amended RED for DDC salts in 2009. 

Ziram (034805) and Ferbam (034801) each had individual REDs in 2003 and 2005, respectively;

registration review dockets for these conventional chemicals are scheduled to open in FY 2015. 

Zinc dimethyldithiocarbamate (034806) was canceled in 1992.

The first product containing NaDDC was registered in 1949, and the first product containing 

KDDC was registered in 1980. 

NaDDC and KDDC are registered for use as material preservatives for fuels, metalworking 

fluids, paints, coatings, adhesives, cloth, and paper/paperboard; they are also registered for use as 

antifoulants/slimicides in a variety of liquids including industrial/commercial cooling water, air 

washer water, sugar mill pulp/process water, marine heat exchangers, gas/oil recovery fluid, 

industrial wastewater treatment systems, industrial water purification systems, reverse osmosis 

water systems, and pasteurizer cooling water. Their main uses reportedly are as antifoulants in 

industrial cooling and air washer water systems, as well as pulp and paper mills and gas/oil 

drilling muds. 

1.5.1 Recent/Pending Regulatory Actions

Several uses of dimethyldithiocarbamate are pending termination/cancellation as of the 

publication of this document, including all wood-preservative/ pressure treatment, as well as 

preservation of adhesives/coatings/emulsions, fuels and oils bottom water, metal working fluids, 

and paints and varnish (EPA registration numbers 1022-563, 1022-574, and 1022-577). EPA 

anticipates issuing the Registration Review generic-data call-in (GDCI) as noted in the 

anticipated schedule in Table 2.

1.5.2 Tolerance Information

EPA has not established a tolerance or exemption from the requirement of a tolerance for 

residues of dimethyldithiocarbamate in food. The Food & Drug Administration (FDA) has 

established a number of food additive regulations for NaDDC. No food additive regulations have 

been established for KDDC. In the case of NaDDC, regulations have been established as a (an):

• Chemical for controlling microorganisms in cane-sugar and beet-sugar mills (21 CFR 

173.320);

• Slimicide used in the manufacture of paper and paperboard that contact food (21 CFR 

176.300);

• Adhesive used as components of articles intended for use in packaging, transporting, or 

holding food (21 CFR 175.105); 

• Rubber article intended for repeated use, used in producing, manufacturing, packing, 

processing, preparing, treating, packaging, transporting, or holding food (21 CFR 

177.2600)
Page 14 of 70

1.6 Incidents

1.6.1 Human Health

There have been no incidents reported in the OPP Incident Database System for the period 

6/30/2009, when the RED Amendment was signed, to the present (search conducted on 

6/18/2013).

1.6.2 Ecological

As of August 6, 2013, no incidents have been reported in the Incident Data System (v. 1.8).
Docket Number EPA-HQ-OPP-2013-0245

www.regulations.gov

Page 15 of 70

2 Anticipated Data Needs

Table 6 presents a summary of the data anticipated as being needed to support this registration review.

Table 6 – Studies Anticipated as Needed for the Registration Review of Dimethyldithiocarbamate 

OCSPP GLN Study Name Test 

Substance

Time 

Frame1

(Months)

Risk Assessment(s) 

Data Will Support

Use Site(s) Triggering Anticipated 

Data Requirement Applicable Exposure Scenario

Studies Anticipated to be Required through the Registration Review DCI

835.31104

835.32205

835.32406

835.32807

Ready biodegradability test or 

one of three biodegradation in 

activated sludge simulation tests

TGAI 12 Activated sludge 

microorganisms All uses Transport to Industrial wastewater treatment plant

835.41003,16 Aerobic soil metabolism

Ethanolami

ne 

(degradate)

24 Wood Preservatives Treated wood in terrestrial 

environments Terrestrial exposure

OECD 209 or 

850.33008

Activated Sludge Respiration 

Inhibition or Modified Activated 

Sludge Respiration Inhibition

TGAI 12 Activated sludge 

microorganisms All uses Transport to Industrial wastewater treatment plant

850.1300 Aquatic invertebrate life-cycle 

toxicity, freshwater TGAI 24 Aquatic organisms Industrial process water; Pulp and paper; Gas/oil, wood preservative3 Transport to the aquatic environment

850.1350 Aquatic invertebrate life-cycle 

toxicity, estuarine/marine TGAI 24 Aquatic organisms Industrial process water; Pulp and paper; Gas/oil, wood preservative3 Transport to the aquatic environment

850.1400 Fish early-life stage, freshwater TGAI 12 Aquatic organisms As above Transport to the aquatic environment

850.30203 Honeybee, acute contact toxicity TGAI 12 Wood preservatives Wood preservatives Treated wood

850.30303 Honeybee, toxicity of residues TGAI 12 Wood preservatives Wood preservatives Treated wood

850.41009 Seedling emergence, Tier II rice TGAI 12 Aquatic organisms Industrial process water; Pulp and 

paper; Gas/oil, wood preservative3 Transport to the aquatic environment

850.415015 Vegetative vigor, Tier II rice TGAI 12 Aquatic organisms Gas/oil Transport to the aquatic environment

850.4400 Aquatic Plant Testing using 

Lemna sp., Tier II TGAI 12 Aquatic organisms As above Transport to the aquatic environment

850.4500

Algal Toxicity Tier II –marine 

diatom, freshwater diatom, and 

green algae

TGAI 12 Aquatic organisms As above Transport to the aquatic environment

850.4550 Algal Toxicity Tier II -

Cyanobacteria TGAI 12 Aquatic organisms As above Transport to the aquatic environment
Page 16 of 70

OCSPP GLN Study Name Test 

Substance

Time 

Frame1

(Months)

Risk Assessment(s) 

Data Will Support

Use Site(s) Triggering Anticipated 

Data Requirement Applicable Exposure Scenario

870.2345 Inhalation Toxicity – 90 Day TGAI 24 Occupational/

Residential Exposure All Use Sites As listed10

870.380011 Reproduction and Fertility 

Effects TGAI 36 Human Health All Use Sites As listed10Dietary and drinking water exposures.

870.4300 Combined Chronic 

Toxicity/Carcinogenicity TGAI 36 Human Health All Use Sites MWF and Wood Preservation12.Dietary and drinking water exposures.

870.5395 Mammalian Erythrocyte 

Micronucleus Test TGAI 12 Human Health All Use Sites All exposure scenarios.

870.7800 Immunotoxicity TGAI 12 Human Health All Use Sites All exposure scenarios

875.120013,14 Indoor Dermal Exposure TGAI 24 Occupational/

Residential Handler All Use Sites As Listed10

875.140013,14 Indoor Inhalation Exposure TGAI 24 Occupational/

Residential Handler All Use Sites As Listed10

875.1700 Product Use Information TGAI 12 Human Health All Use Sites All exposure scenarios.

875.23003 Indoor Surface Residues TGAI 12 Residential Exposure Wood Preservative Toddlers on Decks and Playsets

AWPA 

E11-063 Leaching from treated wood TGAI 12 Wood preservatives Treated wood in terrestrial environments Terrestrial exposure

Special Study Migration Studies TEP 24 Dietary and Aggregate

Cane sugar and beet sugar Mills; 

Coatings, adhesives, paper-making 

additives, and pulp/paper mill 

slimicide use

Dietary/Tier II

Data Needs No Longer Anticipated to be Required from the 2009 RED

GLN Study Name Test 

Substance

Time 

Frame1

(Months)

Reason the Study is No Longer Anticipated to be Required

835.2240 Photodegration in Water TGAI 12 Data were available from active ingredient Thiram, a dimer of DDC acid (MRID 45651201)

835.2410 Photodegradation on Soil TGAI 12 Data were available from active ingredient Thiram, a dimer of DDC acid (MRID 45724501)

835.4100 Aerobic Soil Metabolism TGAI 24 Data were available from active ingredient Thiram, a dimer of DDC acid (MRID 43734901)

835.6100 Terrestrial Field Dissipation TGAI 24

The Agency has reviewed the need for these data and determined that the aerobic soil metabolism halflife of approximately two days indicates limited potential for leaching to ground water or runoff to 

surface water. In addition, the 158 W regulations do not require 835.6100 data (1 40 CFR § 158.2282).

875.1100 Outdoor Dermal Exposure TGAI 24 Exposure scenarios were added to the indoor studies.

875.1300 Outdoor Inhalation Exposure TGAI 24 Exposure scenarios were added to the indoor studies.

875.1600 Application exposure monitoring 

data reporting TGAI 12 This study will be addressed in the submission of the remaining anticipated exposure data requirements
Page 17 of 70

OCSPP GLN Study Name Test 

Substance

Time 

Frame1

(Months)

Risk Assessment(s) 

Data Will Support

Use Site(s) Triggering Anticipated 

Data Requirement Applicable Exposure Scenario

875.2700 Product Use Information TGAI 12 This study will be addressed in the submission of the Product Use Information Study 875.1700

875.2800 Description of Human Activity TGAI 12-24 This study will be addressed in the submission of the Product Use Information Study 875.1700

875.2900 Data Reporting and Calculations TGAI 12 This study will be addressed in the submission of the remaining anticipated exposure data requirements 1

The timeframe will be measured from the receipt of the anticipated DCI. 2

MRID 40220701 was submitted and found to be acceptable for parent compound, but degradates were not identified. As a result, another study is anticipated to 

be required to assess the formation and decline of degradates. 3 EPA has received a request to cancel the only product with a wood preservative use. When the cancellation order becomes effective, this anticipated data 

requirement should no longer be needed.

4 EPA has a published final guideline for this study: http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0152-0017. The biodegradation 

study anticipated to be required is based on results of an Activated Sludge Respiration Inhibition test. 5 EPA has a published final guideline for this study: http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0152-0024. The biodegradation 

study anticipated to be required is based on results of an Activated Sludge Respiration Inhibition test. 6 EPA has a published final guideline for this study: http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0152-0034. The biodegradation 

study anticipated to be required is based on results of an Activated Sludge Respiration Inhibition test.

7 The results of the ASRI test will determine which of these four biodegradation tests is/are anticipated to be required. If the ASRI test EC50 is less than or equal 

to 20 mg/L, then either the (i)Biodegradation in Activated Sludge Study or (ii) Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge Units or (iii) 

the Porous Pot Test is expected to be required. If the ASRI test EC50 is greater than 20 mg/L, then the registrant would likely be required to conduct either: (i) 

Ready Biodegradability or (ii) a) Biodegradation in Activated Sludge or b) Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge Units or c) the 

Porous Pot Test. If the Ready Biodegradability study is conducted and passes, then no further testing would be expected to be required. If, however, the 

antimicrobial fails the Ready Biodegradability study, then the a) Biodegradation in Activated Sludge or b) Simulation Test – Aerobic Sewage Treatment: A. 

Activated Sludge Units, or c) the Porous Pot study would likely be required.

8

The anticipated DCI will provide that 850.3300 may be used in place of OECD 209 if the test substance is not sufficiently soluble to allow preparation of a 

concentrated stock solution in water.

9

Test guidelines 850.4100 and 850.4225 were merged and harmonized into OCSPP 850.4100 in a Federal Register Notice dated June 27, 2012 (FRL-9333-1).

10Indoor exposure scenarios include Open Pour Liquids, Open Pour Wettable Powder, Brush/Roller Application, Airless Spray Application, Wood Pressure 

Treatment and Using Treated MWF. 11Results from a multi-generation (EPA guideline 870.3800) or an extended one-generation reproductive and fertility effects study using OECD Test Guideline 

443 (http://www.oecd-ilibrary.org/environment/test-no-443-extended-one-generation-reproductive-toxicity-study_9789264185371-en) will satisfy this 

requirement.

12 Only the metal working fluid and wood preservation uses may result in long term exposures to workers. 13 Data reporting and calculations are anticipated to be required when handler exposure data are submitted 14 EPA has received requests to cancel the only products with a paints and coatings use and a metal working fluid use. When the cancellation orders become 

effective, this anticipated data requirement should no longer be needed for the brush/roller paint, airless sprayer paint and metal working fluid indoor exposure 

scenarios that are listed in footnote 10. 15 Test guidelines 850.4150 and 850.4250 were merged and harmonized into OCSPP 850.4150 in a Federal Register Notice dated June 27, 2012 (FRL-9333-1).
Page 18 of 70

16 The registrant submitted MRID 43685901 for diethanolamine, a surrogate compound for the dimethylamine (DMA) degradate of NaDDC and KDDC. Until 

this study is reviewed and classified as appropriate for use in the risk assessment, it is included as an anticipated data requirement for use in conducting the risk 

assessment.
Docket Number EPA-HQ-OPP-2013-0245

www.regulations.gov

Page 19 of 70

3 Human Health Risk Assessment

The Agency anticipates the need to conduct a human health risk assessment for DDC salts. The 

Agency expects to require additional data for use in conducting the registration review.

3.1 Existing Toxicological Endpoints 

EPA anticipates the need to revise the existing toxicological endpoints as part of this registration 

review. Table 7 presents a summary of the endpoints used in EPA’s most recent human health 

risk assessment in support of the 2009 RED Amendment. As previously stated, toxicological 

studies were identified as data gaps in the 2009 RED Amendment and identified in the 

registration review as anticipated data needs based on currently registered uses. All available 

information including existing toxicology studies, valid scientific literature, and the studies that 

are expected to be required for registration review will be considered in establishing the 

endpoints to be used in the registration review risk assessment. A summary listing of all of the 

available toxicity studies is provided in Appendix A .

Table 7 –Toxicological Endpoints Used for the Dimethyldithiocarbamate RED

Exposure 

Scenario Dose, UF Study and Toxicological Effects 

Dietary Exposures

Acute Dietary 

(Females 13-50)

Oral NOAEL = 

13 mg/kg/day 

UF = 100A 

Rabbit developmental study (MRID 40995101) 

LOAEL = 38 mg/kg/day based on clinical signs (reddish-colored 

material in cage trays) and possible increased maternal death and 

abortions. 

Acute Dietary 

(General population) 

Oral NOAEL = 

20 mg/kg 

UF = 100A

Co-critical studies: 

Acute neurotoxicity study (MRID 43544201) 

LOAEL = 790 mg/kg/day based on clinical signs of toxicity, 

numerous functional observational battery parameter effects, and 

decreased motor activity. NOAEL = 20 mg/kg/day 

Sub-chronic neurotoxicity study (MRID 43550501) 

LOAEL = 99 mg/kg/day based on salivation, oral staining and 

decreased body weight. NOAEL = 2.0 mg/kg/day 

Chronic Dietary 

(All populations)

Oral NOAEL =

2 mg/kg/day 

UF = 1000B

90-day subchronic oral study (MRID 42047201) 

LOAEL = 100 mg/kg/day and NOAEL = 2 mg/kg/day based on 

decreased erythrocyte counts, increased glucose concentration, and 

increased alkaline phosphatase activity in females, and exocrine 

pancreatic atrophy with fibrosis in males. 

Note: This study had a very wide dose range of 0, 0.2, 2 and 100 

mg/kg/day which resulted in the 50 fold difference between the 

LOAEL of 100 mg/kg/day and the NOAEL of 2 mg/kg/day.

Occupational and Residential Exposures

Incidental oral 

(Short-Term)

Oral NOAEL = 

2 mg/kg/day 

UF = 1000B

90-day subchronic oral study (MRID 42047201) 

Same study used for the chronic dietary scenario above.
Page 20 of 70

Exposure 

Scenario Dose, UF Study and Toxicological Effects 

Incidental Oral 

(Intermediate-Term)

Oral NOAEL = 

2 mg/kg/day 

UF = 1000B

90-day subchronic oral study (MRID 42047201) 

Same study used for chronic dietary above.

Dermal 

(Short, intermediate

and long-term)

Dermal NOAEL 

= 60 mg/kg/day 

UF = 1000B

90-Day Dermal toxicity study (MRID 40140101) 

LOAEL = 120 mg/kg/day 

Based on decreased leukocyte and platelet counts. 

Inhalation 

(Short, intermediate 

and long-term)

Oral NOAEL = 

2 mg/kg/day 

UF = 1000B

90-day subchronic oral study (MRID 42047201) 

Same study used for chronic dietary above.

A. Uncertainty Factor (UF) includes 10X for interspecies extrapolation and 10x for intraspecies variation. 

B. UF includes 10X for interspecies extrapolation, 10x for intraspecies variation and 10x for database 

uncertainty.

3.2 Dietary Exposure 

The Agency anticipates the need to revise the previous dietary risk assessment conducted in 

20093

. Uses of NaDDC and KDDC salts that may result in indirect dietary exposure include 

their use as slimicide in paper mill pulp slurries, material preservatives (including adhesives, 

coatings, and papermaking additives that have the potential to be in food-contact packaging), and 

their use in water process systems for beet sugar mills and cane sugar mills. Additionally, 

drinking water exposure may occur as a result of DDC salts’ use in various industrial process 

water systems and in wood pressure treatment. 

Dietary risk is characterized in terms of the Population Adjusted Dose (PAD), which reflects the 

reference dose (RfD), either acute or chronic, that has been adjusted to account for the FQPA 

Safety Factor (SF). This calculation is performed for each population subgroup for which an 

endpoint exists. A risk estimate that is less than 100% of the acute or chronic PAD is not of 

concern. Acute and chronic dietary risks for DDC salts will be assessed by comparing dietary 

exposure estimates expressed in mg/kg/day to the acute Population Adjusted Dose (aPAD) and 

chronic Population Adjusted Dose (cPAD), respectively.

The Agency also anticipates the need to conduct an aggregate risk assessment. 

3.2.1 Food

NaDDC is considered to be a food additive by the U.S. Food and Drug Administration (FDA) 

under 21 CFR, when used in raw cane and sugar beets. Use limitations for the additive are 3.0 

ppm on a raw cane basis combined with disodium ethylenebisdithiocarbamate for control of 

microorganisms in cane sugar mills and 3.0 ppm on a raw cane or sugar beets basis when 

combined with disodium ethylene bisdithiocarbamate and ethylenediamine for control of 

microorganisms in cane sugar and beet sugar mills (21 CFR §173.320)4. The Agency anticipates 

reassessing dietary risks attributable to the sugar cane and sugar beet uses of NaDDC. The 

Agency anticipates the need to require migration studies in order to refine the risk assessment.

 3 Dietary Risk Assessment for Potassium Dimethyldithiocarbamate for the RED Process,” dated July 14, 2009. 4 21 CFR §173.320
Page 21 of 70

In 2009, the Agency assessed the risks associated with the use of DDC salts in adhesives and 

coatings that have the potential to be in food-contact packaging. FDA guidance for migration 

from food contact surfaces was adapted in the risk assessment5. Based on this guidance, a DDC

salts dietary concentration of 7 ppb was assumed in calculating the Estimated Daily Intake 

(EDI). The Agency anticipates updating the dietary (food) risk assessments for food-contact 

paper/paperboard, paper additives and coatings. The Agency anticipates the need to require

migration studies in order to refine the risk assessment. Dietary exposures will be incorporated 

into the aggregate risk assessment. 

3.2.2 Drinking Water

EPA expects to conduct a Tier I screening-level drinking water analysis to estimate dietary 

exposure from uses that are expected to result in DDC salts passing through WWTPs (see 

Appendix B ). Any drinking water risks will be incorporated into the aggregate risk assessment. 

3.3 Occupational and Residential Exposures 

The occupational and residential exposures to dimethyldithiocarbamate were last assessed in 

D359537 (EPA, 2009b) which was written for the 2009 RED Amendment. The Agency 

anticipates the need to revise the occupational and residential assessments conducted in support 

of the 2009 RED Amendment since the Margins of Exposure (MOE)s were calculated using unit 

exposure data and transferable residue data that have underlying limitations and will need to be 

reassessed using updated values.

3.3.1 Occupational Exposures

EPA anticipates the need to revise the occupational exposure assessment conducted in support of 

the 2009 RED Amendment. There is the potential for both dermal and inhalation exposures 

during the open pouring of dimethyldithiocarbamate liquid and wettable powder (WP) 

formulations. There is a much lower potential for exposure during metering pump addition of 

liquids and water soluble package addition of WP because these addition methods are considered 

to be closed systems. The risks from closed system addition methods were assumed to be

mitigated by label language and were not assessed quantitatively in the 2009 RED Amendment. 

The Chemical Manufacturers Association (CMA) unit exposure data were used for the open pour 

liquid handling scenarios and the Pesticide Handlers Exposure Database (PHED) unit exposure 

data were used for the open pour WP scenarios. The dermal and inhalation MOEs for handling 

liquid formulations of dimethyldithiocarbamate were all greater than the target MOE of 1000 and 

were not of concern. The dermal MOEs for handling wettable powder formulations ranged from 

1 to 6000 and were of concern for most of the scenarios. The inhalation MOEs for handling 

wettable powder formulations ranged from <1 to 2000 and were also of concern.

Machinist Exposure to Dimethyldithiocarbamate Treated Metal Working Fluids

 5 FDA. Guidance for Industry: Preparation of Premarket Submissions for Food Contact Substances: Chemistry 

Recommendations. December 2007. 

http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/IngredientsAdditivesGR

ASPackaging/ucm081818.htm#aii8
Page 22 of 70

DDC salts may be used to treat metal working fluids in accordance with one label (EPA reg. 

number 1022-563). There is a potential for dermal and inhalation exposure when machinists use 

metalworking fluids treated with DDC salts. The dermal exposure was estimated in the 2009 

RED Amendment using the film thickness approach and the resulting dermal MOE was 1200. 

The inhalation exposure was estimated in the 2009 RED Amendment using the OSHA PEL 

approach by adjusting the oil mist concentration by the a.i. concentration and the resulting MOE 

was 2800. EPA has received a product cancellation request for EPA registration number1022-

563. A cancellation order is anticipated to be issued in late 2013.

Pressure Treatment Worker Exposures

DDC salts may be used to pressure treat wood used for decks, buildings, fences, poles, etc., in 

accordance with one label (EPA reg. number 1022-577). These exposures were assessed in the 

2009 RED Amendment using data from a chromated copper arsenate (CCA) exposure study 

(MRID 455021-01) that was sponsored by Arsenical Wood Preservative Task Force of the 

American Chemistry Council. The arsenic portion of the results from this study was used as a 

surrogate to assess DDC salts exposures and these results were normalized to extrapolate the 

measured exposures in the CCA study (monitored at 0.438 to 0.595% arsenic in the CCA 

solution) to the maximum DDC salts treatment solution concentration (10% ai in solution). The 

resulting inhalation MOEs ranged from 400 to 7,600 and were of concern for two scenarios 

because they were less than the target MOE of 1000. The dermal MOEs ranged from 19 to 2200 

and were of concern for most of the scenarios because they were less than the target MOE of 

1000. EPA has received a voluntary cancellation request for EPA registration number 1022-577. 

A cancellation order is anticipated to be issued in late 2013.

Occupational Risk Characterization

Scenarios that Need to be Assessed During Registration Review

All of the handler scenarios that were assessed in the 2009 RED Amendment will need to be 

revised during registration review upon receipt of the unit exposure data that is anticipated to be 

required to supplement or replace the unit exposure data that were used in the 2009 RED

Amendment. Occupational handler scenarios to be assessed are presented in Table 8.

Table 8 – Occupational Exposure Scenarios for the Dimethyldithiocarbamate Salts

Handler Scenarios Exposure 

Route(s) Duration

Open Pour Liquids for treatment of Cooling Water, Drilling Muds, Drilling 

Fluids, Paints and Coatings.

Dermal 

Inhalation 

Intermediate

Term

Open Pour Wettable Powder for treatment of Cooling Water, Drilling Muds, 

Drilling Fluids and Pulp and Papers

Dermal 

Inhalation 

Intermediate 

Term 

Using Treated Metal Working Fluids Dermal 

Inhalation Long Term

Pressure Treatment of Wood Dermal 

Inhalation Long Term

Airless Sprayer and Brush Roller Application of Treated Paints Dermal 

Inhalation 

Intermediate 

Term
Page 23 of 70

3.3.2 Residential Exposures

EPA anticipates the need to revise the residential exposure assessments conducted in support of 

the 2009 RED Amendment. There is one product (EPA reg. number 1022-563) that is labeled 

for use as an in-can preservative of water thinned paints and coatings. There is one product

(EPA reg. number 1022-577) labeled for pressure treatment wood preservation. EPA has 

received a voluntary cancellation request for both products. A cancellation order is anticipated to 

be issued in late 2013.

Residential Handler Exposures for Painting

There is the potential for residential handler exposure during the brush/roller and airless sprayer 

application of paints treated with dimethyldithiocarbamate. Both dermal and inhalation 

exposures are anticipated and are assumed to be primarily short term because painting is done on 

an episodic basis. The risks were assessed in the 2009 RED Amendment using PHED data and

an application rate of 1000 ppm. The dermal MOEs were 910 and 350 for brush/roller and 

airless sprayer application, respectively, and were less than the target MOE of 1000 which means 

that the risks were of concern. The inhalation MOEs were 25,000 and 1,100, respectively, and 

were greater than the target MOE of 1000.

Residential Post Application Exposures from Pressure Treated Wood

There is a potential for child exposure to dimethyldithiocarbamate residues when playing on 

dimethyldithiocarbamate-treated wood structures such as decks and children’s playsets. Both 

dermal and incidental oral exposures are anticipated. These exposures were assessed in the 2009 

RED Amendment using an assumed transferable residue value of 1.0 ug/cm2 that was higher 

than the maximum residue seen for chromium and non-chromium based wood preservatives 

(D330159, EPA, 2006). The dermal MOE was 440 and the incidental oral MOE was 360, both 

of which were less than the target MOE.

Scenarios that Need to be Assessed During Registration Review

The residential handler scenario that was assessed in the 2009 RED Amendment will need to be 

revised during registration review upon receipt of the unit exposure data that is anticipated to be 

required to supplement or replace the unit exposure data that were used in the 2009 RED

Amendment. The post application scenario will need to be revised during registration review 

upon receipt of the transferable residue data that are anticipated to be required to verify the 

assumption that was used in the 2009 RED Amendment. A listing of residential exposure 

scenarios to be assessed is included in Table 9.

Table 9 – Residential Exposure Scenarios for DDC Salts

Scenario Exposure Route(s) Duration

Handler Exposures

Application of Preserved Paint (Brush/Roller and Airless Spray) Dermal 

Inhalation Short Term 

Post Application Exposures

Toddlers Playing on Pressure Treated Decking and Playground Equipment Dermal 

Incidental Oral Intermediate Term
Page 24 of 70

3.4 Aggregate and Cumulative Exposure 

3.4.1 Aggregate Exposures 

EPA anticipates the need to revise the aggregate assessment conducted in support of the 2009

RED Amendment. Upon a reevaluation and selection of toxicological endpoints, combined with 

the human health exposure assessments expected as a part of this registration review case, 

aggregate exposures will need to be assessed. This assessment will include dietary (food) 

exposures and residential exposures. 

3.4.2 Cumulative Exposures

With respect to cumulative exposure, unlike other pesticides for which EPA has followed a 

cumulative risk approach based on a common mechanism of toxicity, the Agency made a 2001 

final determination that there is insufficient data to show a common mechanism of toxicity with 

other substances and dimethyldithiocarbamate does not appear to produce a toxic metabolite 

produced by other substances. For information regarding EPA’s efforts to determine which 

chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such 

chemicals, see http://www.epa.gov/pesticides/cumulative/. 

4 Environmental Risk Assessment 

A risk assessment was conducted for the Amended RED6 (EPA 2009) that assessed acute risks to 

fish and aquatic invertebrates from the use of sodium dimethyldithiocarbamate salt as a wood 

preservative. LOCs were exceeded for acute risk to aquatic organisms for some applications. 

However, in April, 2013, EPA received a request to cancel the only product with a wood 

preservative use. The product cancellation order is expected to be issued in late 2013. For 

currently registered uses, the ecological risk assessment planned during registration review will 

allow the Agency to determine potential acute and chronic risks to aquatic organisms exposed to 

dimethyldithiocarbamate salts that are transported from treatment sites into the aquatic 

environment. Such uses include commercial/industrial cooling water, pulp/paper mill water 

systems, and gas/oil operations. The Agency has not conducted a risk assessment that supports a 

complete endangered species determination for DDC salts. The ecological risk assessment 

planned during registration review will allow the Agency to determine whether DDC salts’ use 

has 'no effect' or 'may affect' federally listed threatened or endangered species (listed species) or 

their designated critical habitats. When an assessment concludes that a pesticide’s use 'may 

affect' a listed species or its designated critical habitat, the Agency will consult with the U.S. 

Fish and Wildlife Service and/or National Marine Fisheries Services (the Services), as 

appropriate.

4.1 Water Quality

Sodium and potassium dimethyldithiocarbamate salts are not identified as a cause of impairment 

for any water bodies listed as impaired under section 303(d) of the Clean Water Act7

. In 

addition, no Total Maximum Daily Loads (TMDL) have been developed for sodium and 

 6 http://www.epa.gov/oppsrrd1/REDs/DDCsalts-red-amended.pdf 7 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885
Page 25 of 70

potassium dimethyldithiocarbamate salts8

. More information on impaired water bodies and 

TMDLs can be found at EPA’s website9.

4.2 Environmental Conceptual Model Exposure Pathways

NaDDC and KDDC salts are active ingredients in antimicrobials that can be used in water 

process systems (air washer, reverse osmosis, and industrial, cane and beet sugar mills in cane 

juice and beet pulp press water, commercial/industrial cooling water, industrial wastewater, 

pulp/paper mills (pulp), gas and oil (drilling muds/packer fluids, recovery injection water, 

fracturing fluids, workover and completion fluids), and coal powered plant flue gas 

desulfurization thickeners). 

Antimicrobials with the above uses will eventually be released to wastewater treatment plants 

(WWTPs) whose effluents will reach surface water and aquatic organisms. The exposure to 

parent compounds is limited because of ready disassociation of the sodium and potassium 

cations from the acid of the DDC salts. The initial exposures will be from a mixture of parent 

compounds and degradates which are impurities because the major degradates were present at 

the beginning of the aerobic aquatic metabolism study.

10 The primary and major (>10 % of 

applied parent compound) degradates include dimethylamine (DMA), carbon disulfide (CS2), 

tetramethylthiuram disulfide (TMTDS), tetramethyl thiomonosulfide (TMTMS), and tetramethyl 

thiourea (TMTU). The oil and gas uses can create environmental exposure of ground water to 

impurities and degradates if well casing is not intact or to surface water if treated water fracking 

water is released into streams. The flue gas desulfurization use is associated with coal-burning 

power plants and there are two forms of waste, water which goes to a WWTP and sludge which 

goes to a landfill.11 As a result, the Agency is assessing the WWTP exposure from the 

desulfurization use but not the landfill disposal because it is assumed that landfills are lined and 

will not create exposure.12

Except as noted, the environmental fate properties of DDC salts and its degradates were based on 

the results of submitted studies. Degradation of DDC salts and its degradates occur by both 

abiotic13 and biotic means14. Parent DDC salts and its degradates are water soluble and will be 

associated with water in the presence of soil, sediment, and sewage sludge. While most DDC

salts compounds have limited potential to volatilize from water based on estimated values using 

the EPI-Suite 4.115 Henry’s Law constants of 10-10 to 10-9 atm m3 mol-1

, DMA and CS2

degradates have Henry’s Law constants of 10-5 to 10-2 atm m3 mol-1 and are likely to volatilize 

from water and create aerial exposure, especially from the cooling tower use (Table B1).

 8

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_

group_name=PESTICIDES

9 http://www.epa.gov/owow/tmdl/

10 MRID 40365702 11 http://water.epa.gov/scitech/wastetech/guide/steam-electric/upload/Steam-Electric_Detailed-StudyReport_2009.pdf , EPA 821-R-09-008 12 http://www.epa.gov/osw/nonhaz/municipal/landfill/criteria/landbig.pdf 13 Hydrolysis (MRID 43180801) and photolysis in water (MRID 40220701) 14 Aquatic metabolism, MRIDs 43865901 and 40365702 15 http://www.epa.gov/opptintr/exposure/pubs/episuite.htm
Page 26 of 70

For all the following conceptual exposure models for DDC salts and its degradates, the Agency 

is using solid lines to signify that surface water exposure and attribute changes can occur, but the 

potential for bioconcentration and secondary exposure is unlikely or insignificant as indicated by 

the dashed lines. 

Figure 1 contains the conceptual model for the environmental exposure from the cooling tower 

use of DDC salts. Based on the lack of data on the persistence in cooling towers and chemical 

and physical properties16 of DDC salts and its degradates, all lines in Figure 1 are solid with the 

exception of ingestion and bioconcentration in aquatic organisms. Water from cooling towers 

will eventually be released to surface water directly or to a WWTP where it will be present in 

water and not be sorbed to the sludge. Treated water from a WWTP will then be released to 

surface water. 

Figure 2 contains the conceptual model for environmental exposure of DDC salts from the water 

system and flue-gas desulfurization (FGD) uses. The water system and FGD uses involve 

scrubbing of SO2 gas from the smokestacks of steam electric power plants that consume fossil 

fuels (e.g. coal). The waste water will eventually pass through a WWTP where it will reach 

surface water. The solid waste (sludge) will be placed in a landfill or other surface impoundment 

or applied to land as a fertilizer and consists of ash (including some heavy metals), CaSO4, and 

CaSO3. The water system and FGD uses contain air washers, reverse osmosis, and industrial 

wastewater systems.17

The conceptual models for the oil and gas uses may be seen in Figures 3 and 4. These uses 

include potential for waste water to be used in irrigation and exposure of terrestrial plants. The 

conceptual model for the wood preservative uses of DDC salts is attached in Figure 5. The wood 

preservative use is based on the sole remaining registered label18 that includes wood 

preservation. 

 16 Water solubility, log Kow, and low potential for sorption 17 EPA 821-R-09-008. October, 2009. Steam Electric Power Generating Point Source Category: Final Details 

Study Report. http://water.epa.gov/scitech/wastetech/guide/steam-electric/upload/Steam-Electric_Detailed-StudyReport_2009.pdf

18 http://www.epa.gov/pesticides/chem_search/ppls/001022-00577-19960423.pdf
Page 27 of 70

Figure 1 – Conceptual Model for Cooling Tower Use of DDC Salts and Ecological Exposure and Effects of 

DDC Salts to Aquatic and Terrestrial Organisms

Stressor

Source

Receptors 

and Exposure 

Routes

Attribute

Change(s)

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in algae

Reduction in prey

Modification of PCEs related 

to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Surface Water

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Ingestion Ingestion

Uptake/gills 

or integument

Aquatic Plants

Non-vascular

Vascular

Uptake or sorption/cell, roots, 

leaves, 

Piscivorous*

Invertebrates

Vertebrates

Phytoplanktivore/ 

Herbivore

Invertebrates

Vertebrates

*As used here this term refers to animals (terrestrial or aquatic) that eat not just fish but any aquatic animal (e.g., amphibians, mollusks, crustaceans, etc.)

Ingestion

Waste Water Treatment Plant (WWTP)

Key

Most likely

exposure pathway 

contributing to risk

Low likelihood of 

contributing to risk

Use of DDC in Cooling Towers (Once Through and Recirculating)

WWTP 

microorganisms

Uptake or 

sorption

Population

Respiration 

inhibition

Direct Discharge
Page 28 of 70

Figure 2 - Conceptual Model for Environmental Exposure of DDC Salts from Water System and Flue-Gas 

Desulfurization (FGD) to Aquatic and Terrestrial Organisms

Stressor

Source

Receptors 

and Exposure 

Routes

Attribute

Change(s)

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in algae

Reduction in prey

Modification of PCEs related 

to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Surface Water

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Ingestion Ingestion

Uptake/gills 

or integument

Aquatic Plants

Non-vascular

Vascular

Uptake or sorption/cell, roots, 

leaves, 

Piscivorous*

Invertebrates

Vertebrates

Phytoplanktivore/ 

Herbivore

Invertebrates

Vertebrates

*As used here this term refers to animals (terrestrial or aquatic) that eat not just fish but any aquatic animal (e.g., amphibians, mollusks, crustaceans, etc.)

Ingestion

Waste Water Treatment Plant (WWTP)

Key

Most likely

exposure pathway 

contributing to risk

Low likelihood of 

contributing to risk

Use of DDC in Water Systems and Flue-Gas Desulfurization

WWTP 

microorganisms

Uptake or 

sorption

Population

Respiration 

inhibition
Page 29 of 70

Figure 3 – Conceptual Model for Aquatic (A) and Terrestrial (B) Environmental Exposure 

of DDC Salts in Recovered Water from Oil and Gas Use 

Stressor

Source

Receptors 

and Exposure 

Routes

Attribute

Change(s)

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in algae

Reduction in prey

Modification of PCEs related 

to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Surface Water

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Ingestion Ingestion

Uptake/gills 

or integument

Aquatic Plants

Non-vascular

Vascular

Uptake or sorption/cell, roots, 

leaves, 

Piscivorous*

Invertebrates

Vertebrates

Phytoplanktivore/ 

Herbivore

Invertebrates

Vertebrates

*As used here this term refers to animals (terrestrial or aquatic) that eat not just fish but any aquatic animal (e.g., amphibians, mollusks, crustaceans, etc.)

Ingestion

Waste Water Treatment Plant (WWTP)

Key

Most likely

exposure pathway 

contributing to risk

Low likelihood of 

contributing to risk

Use of DDC in Hydraulic Fracturing (Fracking) Process for Oil and Gas Exploration

WWTP 

microorganisms

Uptake or 

sorption

Population

Respiration 

inhibition

Recovered Water (Flowback and 

Produced) Disposal Migration into 

Groundwater

(A)

Deep Well 

Injection

Migration into 

Groundwater

Exposed Groundwater from 

Soil Applications see Figure (B)

Stressor

Source/ 

Exposure 

Media

Receptors 

and Exposure 

Routes

Attribute

Change(s)

Individual organisms

Reduced survival 

(emergence*)

Reduced growth

Reduced reproduction**

Food chain

Reduction in prey

Modification of PCEs related 

to prey availability

Habitat integrity

Reduction in primary 

productivity

Reduced cover

Community change

Modification of PCEs 

related to habitat

Terrestrial Animals

Birds (Reptiles, Amphibians)

Mammals

Ingestion

(B)

Key

Most likely

exposure pathway 

contributing to risk

Low likelihood of 

contributing to risk

Recovered Water (Flowback and 

Produced) Open Pit Storage or 

Evaporation Pond

Use of DDC in Hydraulic Fracturing (Fracking) Process for Oil and Gas 

Exploration in Recovered Water 

Irrigation Water

Recovered Water (Flowback and 

Produced) Disposal

Terrestrial plants

Grasses/forbs, fruit, 

seeds, trees, shrubs

Contact/Uptake 

leaves, stems

Soil

Root uptake

Ingestion

*Refers to seedling emergence

**Vegetative vigor and seedling emergence endpoints are assumed to be as sensitive or more sensitive than 

reproduction endpoint and plant reproduction s not explicitly evaluated.

Soil Leaching

Groundwater

See Figure (A) for 

aquatic exposure 

pathways
Page 30 of 70

Figure 4 - Conceptual Model for Aquatic (A) and Terrestrial Environmental Exposure (B)

of DDC Salts from Use in Oil and Gas Extraction, Drilling Muds/Fluids, Hydraulic 

Fracturing Fluids, and Primary, Secondary, and Tertiary (Enhanced Oil) Fluids

Stressor

Source

Receptors 

and Exposure 

Routes

Attribute

Change(s)

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in algae

Reduction in prey

Modification of PCEs related 

to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Surface Water /Sediment

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Ingestion Ingestion

Uptake/gills 

or integument

Aquatic Plants

Non-vascular

Vascular

Uptake or sorption/cell, roots, 

leaves, 

Piscivorous*

Invertebrates

Vertebrates

Phytoplanktivore/ 

Herbivore

Invertebrates

Vertebrates

*As used here this term refers to animals (terrestrial or aquatic) that eat not just fish but any aquatic animal (e.g., amphibians, mollusks, crustaceans, etc.)

Ingestion

Deep Well 

Injection

Key

Most likely

exposure pathway 

contributing to risk

Low likelihood of 

contributing to risk

Use of DDC in Oil and Gas Extraction Drilling Muds/Fluids, Hydraulic, Fracking 

Fluids, Primary, Secondary and Tertiary (Enhanced Oil) Recovery Fluids

WWTP 

microorganisms

Uptake or 

sorption

Population

Respiration 

inhibition

Recovered Water/Fluids (Flowback 

and Produced), Muds Disposal

Migration into 

Groundwater

(A)

Waste Water Treatment Plant (WWTP)

Migration into 

Groundwater

Exposed Groundwater from 

Soil Applications see Figure (B)

Stressor

Source/ 

Exposure 

Media

Receptors 

and 

Exposure 

Routes

Attribute

Change(s)

Individual organisms

Reduced survival 

(emergence*)

Reduced growth

Reduced reproduction**

Food chain

Reduction in prey

Modification of PCEs 

related to prey availability

Habitat integrity

Reduction in primary 

productivity

Reduced cover

Community change

Modification of PCEs 

related to habitat

Terrestrial Animals

Birds (Reptiles, 

Amphibians)

Mammals

Ingestion

(B)

Key

Most likely

exposure pathway 

contributing to risk

Low likelihood of 

contributing to risk

Recovered Water (Flowback and 

Produced) Open Pit Storage or 

Evaporation Pond

Use of DDC in Oil and Gas Extraction Drilling Muds/Fluids, Hydraulic, Fracking Fluids, 

Primary, Secondary and Tertiary (Enhanced Oil) Recovery Fluids

Irrigation Water

Recovered Water (Flowback and 

Produced) Disposal

Terrestrial plants

Grasses/forbs, fruit, 

seeds, trees, shrubs

Contact/Uptake 

leaves, stems

Ingestion

*Refers to seedling emergence

**Vegetative vigor and seedling emergence endpoints are assumed to be as sensitive or more sensitive than 

reproduction endpoint and plant reproduction s not explicitly evaluated.

Soil

Root uptake

Soil Leaching

Groundwater

See Figure (A) 

for aquatic 

exposure 

pathways
Page 31 of 70

Figure 5 - Conceptual Model for Aquatic Environmental Exposure of DDC Salts from Use 

in Pressure Treated Wood

4.3 Ecological Effects Assessment

4.3.1 Mode of Action

NaDDC and KDDC are synthetic broad-spectrum antimicrobial agents. Dithiocarbamate 

fungicides inhibit sulfhydryl (-SH) groups in amino acids, proteins and enzymes of fungal and 

bacterial cells. While these salts are a subgroup of the carbamate pesticides, the Agency made a 

2001 final determination that in animals they do not share a common mechanism of toxicity19. 

The dithiocarbamates all release carbon disulfide (CS2), under acidic conditions, which is toxic 

to the central and peripheral nervous systems. 

4.3.2 Measures of Effect (Ecotoxicology Endpoints)

Ecological effects data are used as measures of direct and indirect effects to aquatic and 

terrestrial organisms. Acute and chronic toxicity data from registrant-submitted studies will be 

used to evaluate the potential direct and indirect effects of the DDC salts and degradates to plants 

 19 http://epa.gov/pesticides/cumulative/

Stressor

Source

Receptors 

and Exposure 

Routes

Attribute

Change(s)

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in algae

Reduction in prey

Modification of PCEs related 

to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Ingestion Ingestion

Uptake/gills 

or integument

Aquatic Plants

Non-vascular

Vascular

Uptake or sorption/cell, roots, 

leaves, 

Piscivorous*

Invertebrates

Vertebrates

Phytoplanktivore/ 

Herbivore

Invertebrates

Vertebrates

*As used here this term refers to animals (terrestrial or aquatic) that eat not just fish but any aquatic animal (e.g., amphibians, mollusks, crustaceans, etc.)

Ingestion

Waste Water Treatment Plant (WWTP)

Key

Most likely

exposure pathway 

contributing to risk

Low likelihood of 

contributing to risk

WWTP 

microorganisms

Uptake or 

sorption

Population

Respiration 

inhibition

Dip, Pad or Pressure 

Treated Wood Process 

Facility Drain

Post-Treated Wood 

Product Storage

Leaching and Run-off

In-Use Service of Wood 

Treated Wood Products

Leaching and Run-off

Surface Water

Sediment
Page 32 of 70

and animals. The ecotoxicity data requirements and all available ecotoxicity endpoints from 

studies submitted by registrants are tabulated in Appendix C .

OPP uses the most sensitive toxicity values for assessing risk to each receptor group. The 

endpoints that will be used for the DDC salts ecological risk assessment are presented in Table 

11. Anticipated data gaps for the TGAI also are indicated. Data also are included for thiram, a 

major reaction product and also a registered active ingredient (PC Code 079801).

Table 11. Selected Ecological Effects Endpoints for Risk Assessment

Receptor 

Group

Surrogate 

Species

Test

material

Risk

Scenario

Toxicity

Endpoint

EPA

ID

Freshwater fish

Fathead minnow KDDC

Acute 96-h LC50 = 60 μg ai/L 240946

Chronic Data gap N/A

Bluegill

Thiram Acute 96-h LC50 = 42 μg ai/L 070801

Thiram 

estimated using 

ACR

Chronic NOAEC = 0.36 μg ai/L See Appendix 

C

Freshwater 

invertebrates Waterflea

NaDDC

Acute 48-h EC50 = 52 μg ai/L 42504802 

Chronic Data gap N/A

Thiram

Acute 48-h EC50 = 210 μg ai/L 164662

Chronic Under Review N/A

Estuarine/marine 

fish

Sheepshead

minnow

NaDDC

Acute 96-h LC50 = 59,000 μg ai/L 41984701

Chronic Not a data gap: Mysid is 

more acutely sensitive N/A

Thiram

Acute 96-h LC50 = 540 μg ai/L 42514401

Chronic Not a data gap: Mysid is 

more acutely sensitive N/A

Estuarine/marine 

invertebrates Mysid

NaDDC

Acute LC50 = 88 μg ai/L 42561901

Chronic Data gap N/A

Thiram

Acute LC50 = 3.36 μg ai/L 42488302

Chronic Will use generated ACRs N/A

Aquatic nonvascular plants

Green algae, 

Freshwater 

diatom, 

Estuarine/marine 

diatom, and

Cyanobacteria

DDC salts IC50 and 

NOAEC Data gap N/A

Green algae Thiram

Non-listed IC50 = 45 μg a.i/L

42646001

Listed NOAEC <57 μg a.i/L (will 

calculate IC05)

Aquatic vascular

plants Lemna sp.

TGAI IC50 and 

NOAEC Data gap N/A

Thiram Non-listed IC50 = 1,600,000 μg a.i/L 45441202
Page 33 of 70

Receptor 

Group

Surrogate 

Species

Test

material

Risk

Scenario

Toxicity

Endpoint

EPA

ID

Listed species NOAEC <57,000 μg a.i/L

(will calculate IC05)

Semi-aquatic 

plants (seedling 

emergence)

Rice TGAI IC50 and 

NOAEC Data gap N/A

Vegetative Vigor Multiple species TGAI IC50 and 

NOAEC Data gap N/A

Birds

Northern 

bobwhite

NaDDC 

(40) Acute LD50 = 391 mg ai/kg bw 00159788

Ring-necked 

pheasant Thiram (99) Acute LD50 = 673 mg ai/kg bw 00160000

Mallard Thiram (97.5) Chronic NOAEC = 9.6 ppm 45441201

Beneficial insects Honeybee TGAI Acute Data gap NA

4.4 Exposure Analysis Plan

4.4.1 Aquatic and Terrestrial Wildlife Exposure Estimates

In order to address the risk hypothesis, the potential for adverse effects on the environment will 

be estimated. For down-the-drain (DtD) risk estimates, an approach that estimates the number of 

days a concentration-of-concern (COC) is exceeded, also referred to as a probabilistic dilution 

model (PDM) approach is used to assess risk to aquatic organisms.

4.4.2 Screening Level Down-the-Drain Analysis

The Industrial Releases Module of the E-FAST (Exposure and Fate Assessment Screening Tool) 

will be used to determine the potential for aquatic organisms downstream of the industrial

wastewater treatment plants that receive discharges from the end-use of KDDC and NaDDC to 

be exposed these chemicals or their degradates. NaDDC and KDDC salts are used in industrial 

water systems such as commercial/industrial cooling water, industrial wastewater, pulp/paper 

mills, etc. Antimicrobials with these uses will eventually be released to industrial wastewater 

treatment plants whose effluents will reach surface water and aquatic organisms. The primary 

and major (>10 % of applied parent compound) degradates include the DMA, CS2, TMTDS, 

TMTMS, and TMTU. Chemicals that are released down-the-drain can typically take from a few 

to several hours to reach wastewater treatment plant intakes following their discharge and from 

several hours to roughly a day following their discharge down-the-drain to subsequently be 

discharged from industrial wastewater treatment plants to surface water. The half-life of both 

KDDC and NaDDC are long enough to enter the industrial wastewater treatment plants and 

subsequently be discharged to surface waters.

This analysis plan will be revisited and may be revised depending upon a full review of the data

available in the open literature and the information submitted by the public in response to the

opening of the Registration Review docket. The Agency does not anticipate requiring additional 

data to assess down-the-drain exposures for this registration review.
Page 34 of 70

4.5 Effects Analysis Plan

Additional open literature studies will be identified through EPA’s ECOTOXicology (ECOTOX) 

database20, which employs a literature search engine for locating chemical toxicity data for 

aquatic life, terrestrial plants, and wildlife. The ECOTOX database will be searched when the 

risk assessment for the DDC salts is prepared. Open literature studies will be reviewed that 

potentially provide data for missing endpoint values or provide values more sensitive than 

available from the anticipated registrant-submitted studies. ECOTOX was created and is 

maintained by the USEPA, Office of Research and Development, and the National Health and 

Environmental Effects Research Laboratory's Mid-Continent Ecology Division.

5 Endocrine Disruptor Screening Program (EDSP)

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse 

outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and 

chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, 

reproductive, and general or systemic toxicity. These studies include endpoints which may be 

susceptible to endocrine influence, including effects on endocrine target organ histopathology, 

organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, 

and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and 

chronic studies that assess growth, developmental and reproductive effects in different 

taxonomic groups. As part of the 2009 Amended RED, for DDC salts, EPA reviewed these data 

and selected the most sensitive endpoints for relevant risk assessment scenarios from the existing 

hazard database. However, as required by FFDCA section 408(p), DDC salts are subject to the

endocrine screening part of the Endocrine Disruptor Screening Program (EDSP). 

EPA has developed the EDSP to determine whether certain substances (including pesticide 

active and other ingredients) may have an effect in humans or wildlife similar to an effect 

produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator 

may designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine-related effects caused by the substance, and

establish a dose-response relationship between the dose and the E, A, or T effect. 

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 

2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, 

which contains 58 pesticide active ingredients and 9 inert ingredients. NaDDC and KDDC are

not among the group of 58 pesticide active ingredients on the initial list to be screened under the 

EDSP. Accordingly, as part of registration review, EPA will issue future EDSP orders/data callins, requiring the submission of EDSP screening assays for NaDDC and KDDC.

 20 http://cfpub.epa.gov/ecotox/
Page 35 of 70

For further information on the status of the EDSP, the policies and procedures, the list of 67 

chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit our 

website: http://www.epa.gov/endo/. 

6 Guidance for Commenters 

6.1 Preliminary Work Plan 

The public is invited to comment on EPA’s Preliminary Work Plan and rationale. The Agency 

will carefully consider all comments as well as any additional information or data provided in a 

timely manner prior to issuing a final work plan for the Sodium and Potassium 

Dimethyldithiocarbamate Salts registration review case. 

6.1.1 Trade Irritants 

Through the registration review process, the Agency intends to solicit information on trade 

irritants and, to the extent feasible, take steps toward facilitating irritant resolution. The Agency 

will work to harmonize tolerances and international maximum residue limits (MRLs) and may 

modify tolerance levels to do so, when possible. Stakeholders are asked to comment on any 

trade irritant issues resulting from lack of MRLs or disparities between U.S. tolerances and 

MRLs in key export markets, providing as much specificity as possible regarding the nature of 

the concern.

6.1.2 Water Quality 

See section 4.1. The Agency invites submission of water quality data for this pesticide. To 

the extent possible, data should conform to the quality standards in Appendix A of the OPP 

Standard Operating Procedure: Inclusion of Impaired Water Body and Other Water Quality 

Data in OPP’s Registration Review Risk Assessment and Management Process21 in order to 

ensure they can be used quantitatively or qualitatively in pesticide risk assessments.

6.1.3 Environmental Justice 

EPA seeks to achieve environmental justice, the fair treatment and meaningful involvement of all 

people, regardless of race, color, national origin, or income, in the development, implementation, 

and enforcement of environmental laws, regulations, and policies. To help address potential 

environmental justice issues, the Agency seeks information on any groups or segments of the 

population who, as a result of their location, cultural practices, or other factors, may have 

atypical, unusually high exposure to sodium and potassium dimethyldithiocarbamate salts 

compared to the general population. Please comment if you are aware of any sub-populations 

that may have atypical, unusually high exposure compared to the general population.

6.1.4 Structure Activity Relationships 

EPA must rely upon information of appropriate quality and reliability for each decision made by 

the Agency. In the Office of Pesticide Programs (OPP), the evaluation process for a pesticide 

 21 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm
Page 36 of 70

chemical traditionally begins with the applicant’s submission of a set of studies conducted with 

the specific pesticide chemical of interest. The use of the results of such testing (measured data) 

is a logical, scientifically rigorous process that identifies the physical, chemical, and 

environmental fate properties of the pesticide, as well as the dose and endpoints at which an 

adverse effect can occur in various animal species. 

Today, there is significant interest in alternative techniques, i.e., techniques other than data 

generation that could significantly inform the Agency’s decision-making process. Recently, OPP 

has made increasing use of structure activity relationship (SAR) as part of its regulatory 

decision-making process. In the SAR process, a chemical's molecular structure is compared to 

that of other chemicals for which data are available. These structural similarities are then used to 

make predictive judgments about a chemical’s physical, chemical, and biological properties. 

Thus, the chemical’s physical, chemical, and biological properties are a function of (or directly 

related to) the chemical’s molecular structure. Quantitative SAR is referred to as QSAR. To 

develop a QSAR, a selected set of measured data on a single physical, chemical, or biological 

property is used to derive a model (an equation) to predict the value of that property. 

Since SAR assessments and QSAR modeling are another set of tools that are available to Agency 

scientists, OPP has begun a process shift that envisions shifting from the current study-by-study 

approach to an approach in which the use of predicted data, generated using validated models, is 

considered along with information from open literature and studies specifically generated under 

Part 161 requirements. All relevant information would be considered as part of a weight-of-theevidence evaluation. 

At this time, EPA believes that for certain endpoints, especially physical/chemical and fate 

properties, that SAR and QSAR might be effectively utilized to fulfill these data requirements 

for many antimicrobial pesticide chemicals. When considering biological properties, at this time, 

EPA believes that SAR and QSAR can be most effectively utilized in the evaluation of 

chemicals that exhibit lower toxicity for human health and/or ecotoxicity parameters. This is 

appropriate because the risk assessment for lower toxicity chemicals can be stream-lined, i.e., a 

screening-level assessment procedure rather than multiple tiers of assessments with progressively 

more data requirements. 

If stakeholders believe that submission of predicted data can fulfill one of the data needs for the 

Sodium and Potassium Dimethyldithiocarbamate Salts Case, then the Agency invites submission 

of this information. The submitter would be expected to supply a rationale describing the utility 

of the information and provide documentation on the scientific validity of the information. The 

determination that the predicted data fulfills the data requirement would be at the sole discretion 

of the Agency. Pre-submission consultation with the Agency is encouraged. 

6.1.5 Additional Information

Stakeholders are also specifically asked to provide available information and data that will assist 

the Agency in refining its risk assessments, including any species-specific ecological effects 

determinations. The Agency is interested in receiving the following information: 

1. Confirmation on the following label information: 
Page 37 of 70

A. Sites of application 

B. Formulations 

C. Application methods and equipment 

D. Maximum application rates 

E. Frequency of application, application intervals and maximum number of 

applications 

F. Geographic limitations on use 

2. Use or potential use distribution 

3. Use history 

4. Usage/use information for non-agricultural uses (e.g., materials preservation) 

5. Typical application interval 

6. State or local use restrictions 

7. Ecological incidents (non-target plant damage and avian, fish, reptilian, amphibian and 

mammalian mortalities) not already reported to the Agency 

8. Monitoring data 

7 Next Steps

After the 60-day comment period closes in November 2013, the Agency will review and respond 

to any comments received in a timely manner, and then issue a Final Work Plan for the Sodium

and Potassium Dimethyldithiocarbamate Salts case.
Page 38 of 70

8 References

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received Jul 7, 1975 under 9386-7; submitted by Vinings Chem Co., Atlanta, GA; CDL: 

234870-A. MRID 00104057.

Anonymous. 1978. Report of Laboratory Investigations. Unpublished study prepared by 

Sharpley Laboratories, Inc., Fredericksburg, VA. Acc. No. 240946.

Beavers, J. 1986. SDDC: An Acute Oral Toxicity Study with the Bobwhite: Final Report: Project 

No. 211-106. Unpublished study prepared by Wildlife International Ltd. 18 p. MRID 

00159788.

Bodden, R. 1982. Avian Single-dose Oral LD50 Bobwhite Quail: Study No. 6026-101. 

Unpublished study received Jun 3, 1982 under 1448-70; prepared by Hazleton 

Laboratories America, Inc., submitted by Buckman Laboratories, Inc., Memphis, TN; 

CDL: 247734-B. MRID 00105155.

Burke, K.; Patterson, S. 1990. Physical and Chemical Characteristics of Aquatreat KM: Lab 

Project Number: D-08-004. Unpublished study prepared by National Starch and Chemical 

Co. 5 p. MRID 41609407.

Burke, K.; Patterson, S. 1990. Physical and Chemical Characteristics of Aquatreat SDM: Lab 

Project Number: D-08-004. Unpublished study prepared by National Starch and Chemical 

Co. 5 p. MRID 41609403.

Coates, M. 1996. Thiram: Algal Growth Inhibition: Addendum to MRID 426460-01: Lab Project 

Number: UCB 442/960953: UCB 442/921255. Unpublished study prepared by 

Huntingdon Life Sciences, Ltd. 10 p. MRID 44086101.

Cohen, S. 1994. Sodium Dimethyldithiocarbamate (SDDC): Hydrolysis of SDDC in Buffered 

Aqueous Solutions: Final Report: Lab Project Number: ME 9300155. Unpublished study 

prepared by Univ. of Pittsburgh Applied Research Center. 206 p. MRID 43180801.

Conzelmann, P. 1982. Static 96-hour Marine Bioassay Testing Vinings Antimicrobial Agent 

AMA-31 on American Oyster: GSRI Project No. 415-A60-41. Unpublished study 

received Apr 22, 1982 under 9386-7; prepared by Gulf South Research Institute, 

submitted by Vinings Chemical Co., Atlanta, GA; CDL:247417-D. MRID 00100704.

Conzelmann, P. 1982. Static 96-hour Marine Bioassay Testing Vinings Antimicrobial Agent 

AMA-31 on Blue Crab: GSRI Project No. 415-A60-41. Unpublished study received Apr 

22, 1982 under 9386-7; prepared by Gulf South Research Institute, submitted by Vinings 

Chemical Co., Atlanta, GA; CDL:247417-C. MRID 00100703.

Conzelmann, P. 1982. Static 96-hour Marine Bioassay Testing Vinings Antimicrobial Agent 

AMA-31 on Grass Shrimp: GSRI Project No. 415-A60-41. (Unpublished study received 
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Apr 22, 1982 under 9386-7; prepared by Gulf South Research Institute, submitted by 

Vinings Chemical Co., Atlanta, GA; CDL:247417-A) MRID 00107905

Conzelmann, P. 1982. Static 96-hour Marine Bioassay Testing Vinings Antimicrobial Agent 

AMA-31 on Sheepshead Minnow: GSRI Project No. 415-A60-41. (Unpublished study 

received Apr 22, 1982 under 9386-7; prepared by Gulf South Research Institute, submitted by Vinings Chemical Co., Atlanta, GA; CDL:247417-B) MRID 00107906

Croudace, C.; Caunter, J.; Johnson, P. 1992. Thiram: Acute Toxicity to Sheepshead Minnow 

(Cyprinodon variegatus): Lab Project Number: W199/B. Unpublished study prepared by 

Imperial Chemical Industries PLC. 22 p. MRID 42514401.

Douglas, M. 1993. Thiram: Algal Growth Inhibition (Selenastrum capricornutum): Lab Project 

Number: UCB 442/921255. Unpublished study prepared by Huntingdon Research Centre 

Ltd. 30 p. MRID 42646001.

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Dimethyldithiocarbamate. Unpublished study prepared by R. T. Vanderbilt Co., Inc. in 

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40365701.

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Page 43 of 70

Appendix A Toxicology Profile for 

Dimethyldithiocarbamate

I. BACKGROUND

Both sodium dimethyldithiocarbamate and potassium dimethyldithiocarbamate react with water 

readily and decompose into their respective salts. Due to their structural and chemical similarities

as shown in Table 1, the bridging of their toxicological databases was ascertained. A consensus 

was reached on bridging the repeat exposure database of both sodium dimethyldithiocarbamate 

and potassium dimethyldithiocarbamate in the ADTC endpoint selection meeting (US EPA, 

2009). However, the acute toxicological database could not be bridged due to lack of data on the 

technical active ingredient on each of the chemicals.

Table 1. Chemical structures

Sodium dimethyldithiocarbamate Potassium dimethyldithiocarbamate

Adapted from RED, Table 1. p. 1

II. Acute Toxicity

A. Sodium dimethyldithiocarbamate

The acute toxicity summary for sodium dimethyldithiocarbamate is provided in Table 2. Sodium 

dimethyldithiocarbamate is corrosive to the eye and causes mild or slight irritation to skin. The 

toxicity study with sodium dimethyldithiocarbamate yielded a Toxicity Category II with dermal 

route of exposure and a Toxicity Category IV with inhalation route of exposure study. There 

were no acceptable acute oral toxicity studies available; however, an unacceptable / guidelineupgradeable study’s (MRID 00160993, 00160994) results were considered. An acute oral study 

for the sodium salt is anticipated to be required for the product specific data call in (PDCI). 
Page 44 of 70

Table 2. Acute toxicity database for sodium dimethyldithiocarbamate

Guideline 

No.

Study Type MRID number (s) Results Toxicity 

Category

81-1 Acute Oral No acceptable study 

available.

LD50 (M) = 2100 mg/kg 

LD50 (F) = 2500 mg/kg 

III

81-2 Acute Dermal 00160995, 92043009 LD50 (M) = 1450 mg/kg 

LD50 (F) = 1020 mg/kg

II

81-3 Acute Inhalation 00159769, 42327801, 

92043010

LC50 (M) > 2.22 mg/L

LD50 (F) > 2.22 mg/L

IV

81-4 Primary Eye 

Irritation

00161185, 92043011 Corrosive I

81-5 Primary Skin 

Irritation

00159782, 43481501, 

92043012

Mild or slight IV

81-6 Dermal 

Sensitization

00159783, 92043013 Negative 

Adapted from RED (2009), Table 5, p. 9

B. Potassium dimethyldithiocarbamate

The acute toxicity summary table for potassium dimethyldithiocarbamate is provided in Table 2.

Potassium dimethyldithiocarbamate is a dermal sensitizer and causes moderate dermal irritation. 

The primary eye irritation study was assigned a Toxicity Category of III with the corneal 

involvement reversible within 7 days. A Toxicity Category III was assigned to both acute oral 

and dermal toxicity studies. No inhalation study was provided. An acute inhalation toxicity 

study for the potassium dimethyldithiocarbamate is anticipated to be required for the PCDI. 

Table 3. Acute toxicity database for potassium dimethyldithiocarbamate

Guideline 

No.

Study Type MRID (s) Results Toxicity 

Category

81-1 Acute Oral 00132382, 

92039001

00143448*

LD50 (M) = 2196 mg/kg 

(LD50 (F) = 1867 mg/kg 

III

81-2 Acute Dermal 00146768, 

92039002

00132381*

00143449*

LD50 (M) = 2990 mg/kg III

81-3 Acute Inhalation No study available 

81-4 Primary Eye 

Irritation

00105157, 

92039003

PIS: 32.2/110 unwashed, 

PIS: 40.7/110 washed

III**

81-5 Primary Skin 

Irritation

00105157, 

92039004

Primary Irritation Index: 

3.08 after 72 hours

III

81-6 Dermal 

Sensitization

00132380, 

92039005

Positive 

Adapted from RED, Table 6, p. 10

* MRIDs 00143448, 00132381, and 00143449 not included in the table, but included in toxicology profile 

** An unacceptable primary eye irritation study (MRID 00143448) was assigned a Toxicity Category II.
Page 45 of 70

III. Repeat Dose Toxicity

The toxicological database of repeat dose studies for dimethyldithiocarbamate is listed in Table 

3. All of these studies were included in the hazard assessment that was written for the RED (US 

EPA, 2009). No new studies have been submitted since the publication of the RED, and no data 

are anticipated to be required. Summaries of the toxicity profiles for Sodium 

dimethyldithiocarbamate and Potassium dimethyl-dithiocarbamate are included in Tables 4 and 

5, respectively.

Table 4. Toxicological Database of Repeat Dose Studies for Dimethyldithiocarbamate

Guideline 

Number

Study Required Satisfied MRID Number(s)

(Chemical)

870.3100 90-Day Oral - Rats Yes Yes 42047201 (NaDDC)

870.3250 90-Day Dermal -Rats Yes Yes 40830801 (KDDC)

870.3250 90-Day Dermal -Rabbit Yes Yes 40140101 (NaDDC)

870.3700a Developmental Toxicity- Rats Yes Yes 40140102 

(NaDDC), 

41005501 (KDDC)

870.3700b Developmental Toxicity- Rabbits Yes Yes 40165804 

(NaDDC), 

40995101 (KDDC)

870.3800 Reproduction and Fertility Effects Yes No 42905, 82096*

870.4100a Chronic Toxicity – Rats Yes No 82096*

870.4100b Chronic Toxicity – Dogs No No 82905*

870.5100 Bacterial Reverse Mutation Test Yes Yes 159688 (NaDDC), 

40631103 (KDDC)

870.5300 In vitro Mammalian Cell Gene Mutation Test Yes Yes 159779 (NaDDC), 

4089901 (KDDC)

870.5375 In vitro mammalian chromosome aberration 

test

Yes Yes 159681 (NaDDC)

870.5550 Unscheduled DNA Synthesis in Mammalian 

Cell Culture

Yes Yes 40631101 (KDDC)

870.5900 In vitro Sister Chromatid Exchange Assay Yes Yes 159778 (NaDDC), 

40631102 (KDDC)

870.6200 Neurotoxicity Screening Battery Yes Yes 43544201 (NaDDC)

870.6200 Neurotoxicity Screening Battery Yes Yes 43550501 (NaDDC)

Adapted from RED, Table 4, p. 7.

*MRID numbers not in references or profile
Page 46 of 70

Table 5. Toxicity Profile of Sodium Dimethyldithiocarbamate (excluding acute studies)

Guideline No./

Study Type

MRID No./

Study 

Classification

Animals Tested and Dose 

Administered Results

Subchronic Toxicity

870.3100

90-Day Oral 

Subchronic

(Rat)

MRID 42047201

Acceptable

Core-Minimum

10 Sprague-Dawley rats/sex/dose

Gavage dose at 0.2, 2, or 100 

mg/kg/day for 13 weeks.

LOAEL = 100 mg/kg/day, based on 

decreased erythrocyte counts, increased 

glucose concentration, and increased 

alkaline phosphatase activity in females, 

and exocrine pancreatic atrophy with 

fibrosis in males.

NOAEL = 0.2 mg/kg/day

870.3250

90-Day Dermal

(Rabbit)

MRID 40140101

Acceptable/

Guideline

10 New Zealand White 

rabbits/sex/dose

Dermal dose to the clipped 

unabraded dorsal surfaces at 0, 

20, 60, or 120 mg/kg/day, 6 

hours/day, 5 days/week for 13 

weeks.

Systemic Toxicity

LOAEL = 120 mg kg/day, based on 

decreased leukocyte and platelet counts.

NOAEL = 60 mg/kg/day 

Dermal Irritation

LOAEL = 20 mg/kg/day, based on 

redness, edema, and/or desquamation at 

the treatment site.

NOAEL Not Determined

Developmental Toxicity

870.3700a 

Developmental 

Toxicity 

(Rat)

MRID 40140102

Acceptable 

22 Female Sprague-Dawley 

rats/dose

Gavage in water at 0, 2, 20, or 

200 mg/kg/day on gestation days 

6-15, inclusive. On GD 20, dams 

were sacrificed and necropsied.

Maternal Toxicity

LOAEL = 2 mg /kg/day based on 

decreased corrected body weights.

NOAEL Not Determined

Developmental Toxicity

LOAEL Not determined

NOAEL ≥ 200 mg/kg/day

No treatment related effects 

870.3700b

Developmental 

Toxicity 

(Rabbit)

MRID 40165804

Acceptable

18 New Zealand White 

rabbits/dose

Administered by gavage in 

distilled water at doses of 0, 0.4, 

4, or 40 mg/kg/day on gestation 

days 7-19, inclusive. On GD 29, 

surviving does were sacrificed 

and necropsied. 

Maternal Toxicity

LOAEL = 40 mg/kg/day, based on 

decreased body weights. 

NOAEL = 4 mg/kg/day

Developmental Toxicity 

LOAEL Not Determined

NOAEL ≥ 40 mg/kg/day

There were no treatment related effects

Mutagenicity

870.5100

Bacterial Reverse 

Mutation Test

MRID 00159688

Acceptable

Concentrations of 4, 40, 133, 400

or 1333 μg ai/plate. 

Positive

Positive results (frequencies of revertants 

greater than twice solvent control) were 

registered in three strains (TA100, 

TA1535, and TA1537), both with/without 

metabolic activation at non-cytotoxic dose 

levels (lowest dose levels at which effects 

occurred: 4 or 40 μg/plate ± S9). 
Page 47 of 70

870.5300

In Vitro 

Mammalian Cell 

Gene Mutation 

Test

MRID 00159779

Acceptable 

Chinese Hamster Ovary Cells Negative

870.5375

In Vitro 

mammalian 

chromosome 

aberration test

MRID 00159681 

Acceptable 

Chinese Hamster Ovary Cell 

Cultures

Positive in the presence of S9

870.5900

In Vitro Sister 

Chromatid 

Exchange Assay

MRID 00159778

Acceptable 

Chinese Hamster Ovary Cell 

Cultures

Negative

Neurotoxicity

870.6200

Neurotoxicity 

Screening Battery

MRID 43544201

Acceptable 

17 Sprague-Dawley rats/sex/dose 

Single gavage doses of 0, 20, 400, 

or 790 mg/kg/day. 

Neurotoxicity 

NOAEL = 20 mg /kg/day 

LOAEL = 400 mg /kg/day based on 

clinical signs of toxicity, numerous FOB 

parameter effects and decreased motor 

activity 

ChE Inhibition

NOAEL= 790 mg /kg/day (HDT)

There were no test material-related effects 

on plasma, RBC, or brain ChE activity for 

males or females at any dose level. 

870.6200

Neurotoxicity 

Screening Battery

MRID 43550501

Acceptable

15 Sprague-Dawley rats/sex/dose 

Gavaged at daily doses of 0, 0.2, 

2, or 99 mg/kg/day for 13 weeks.

Systemic (Clinical) Toxicity

NOAEL = 2 mg/kg/day.

LOAEL = 99 mg/kg/day based on 

Salivation, oral staining and decreased 

body weight.

Neurotoxicity

NOAEL > 99 mg/kg/day, except for 

minor clinical effects at the HDT 

(salivation; wet-mouth staining; decreased 

body weight of 2% - 8% in males; 2% to 

6% in females), no significant neurotoxic 

or other systemic effects were recorded.

Adapted from RED, Table A3, p. 46

Table 6. Toxicity Profile of Potassium Dimethyldithiocarbamate (excluding acute studies)

Guideline No./

Study Type

MRID No./

Classification

Dosing and Animal 

Information Results

Subchronic Toxicity 

870.3200

21-Day Dermal

(Rat)

MRID 40747003 

Supplementary

A pilot study for 

90-day dermal 

study (MRID 

Sprague-Dawley Rat 

(5/sex/dose)

Doses of 0, 51.3, 128, 257, 385, 

or 513 mg/kg/day, respectively 

were applied 5 days/week for 3 

Dermal Irritation 

NOAEL: 257 mg/kg/day 

LOAEL: 385 mg/kg/day, based on slight 

dermal irritation in 2-3 females but not 

males. In addition, at 1000 mg/kg/day 3/5 
Page 48 of 70

40830801) weeks. A gauze patch was 

applied to the dosing area for 6 

hours per day.

males and 5/5 females exhibited slight 

dermal irritation 

Systemic Effects

NOAEL: 257 mg/kg/day 

LOAEL: 385 mg/kg/day based on female 

body weight gain decrement and reduced 

food efficiency. 

870.3250

90-Day Dermal

(Rat)

MRID 40830801

Acceptable

Core-Minimum

10 Sprague Dawley 

Rats/sex/dose 

Doses of 0, 38.5, 180, or 385 

mg/kg/day for 6 hr/day, 5 d/wk 

for 13 weeks.

Dermal Irritation

LOAEL = 180 mg/kg/day, based on mild 

to moderate acanthosis, partial eschar, and 

ulceration, with ulceration occurring at 

385 mg a.i./kg/day 

NOAEL: 38.5 mg/kg//day

Systemic Effects

LOAEL = 385 mg/kg/day, based on 

reduced body weight in males, decreased 

erythrocyte count and hematocrit in males, 

and hemosiderosis in the spleens of both 

sexes. 

NOAEL = 180 mg a.i./kg/day

Developmental Toxicity - Teratogenicity

870.3700a 

Developmental 

Toxicity 

(Rat)

MRID 40747001

Supplementary -

Pilot Study for the 

main study MRID 

41005501

8 Sprague-Dawley Rats/dose

Doses via gavage to pregnant 

rats at 0, 51.3, 103, 205, 308, 

410 mg/kg/day respectively from 

gestation days 6 through 15. 

Developmental Toxicity

NOAEL = 51 mg/kg/day 

LOAEL = 205 mg/kg/day, based on postimplantation loss and fetal weight 

decrements at 600 mg/kg/day and above 

Maternal Toxicity

NOAEL < 51 mg/kg/day

LOAEL <51 mg kg/day, based on body 

weight gain decrements. Salivation at 103

mg ai/kg/day and above. 

870.3700a 

Developmental 

Toxicity

(Rat)

MRID 41005501

Acceptable

28 Sprague-Dawley Rats/dose

Doses via gavage in water at 0, 

0, 12.8, 77, or 205 mg/kg/day, 

on gestation days 6-15, 

inclusive. On GD 20, dams were 

sacrificed and necropsied. 

Maternal Toxicity 

LOAEL: 77 mg/kg/day, based on reduced 

body weights and body weight gains and 

reduced food consumption.

NOAEL: 12.8 mg/kg/day 

Developmental Toxicity

NOAEL: ≥ 205 mg/kg/day(HDT) 

At 205 mg a.i./kg/day, mean fetal weight 

was marginally decreased. 

870.3700a 

Developmental 

Toxicity 

(Rabbit)

MRID 40747002

Supplementary –

Pilot Study for 

the main study 

MRID 40995101

6 female rabbits/dose. 

Dose was via gavage to pregnant 

rats at doses of 0, 12.8, 26.6, 77, 

154, or 256 mg/kg/day from 

gestation days 6 through 18. 

Developmental Toxicity

NOAEL: 75 mg/kg/day

LOAEL: 77 mg/kg/day based on postimplantation loss and fetal weight 

decreases. 

Maternal Toxicity

NOAEL: 26.6 mg/kg/day 

LOAEL: 77 mg/kg/day based on body 

weight gain decrements. 

Death occurred at 154 and 256 mg/kg/day
Page 49 of 70

870.3700a 

Developmental 

Toxicity

(Rabbit)

MRID 40995101

Acceptable

20 inseminated female 

Rabbits/dose

Dose by gavage in water at 0, 0, 

12.8, 38, or 77 mg/kg/day on GD 

6-18, inclusive. On GD 29, the 

does were sacrificed and 

necropsied. 

Maternal Toxicity

LOAEL: 38 mg/kg/day, based on clinical 

signs (reddish-colored material in cage 

trays), and possible increased maternal 

death and abortions.

NOAEL: 12.8 mg /kg/day

Developmental Toxicity

LOAEL: 38 mg /kg/day, based on 

malalignment of sternebrae, increased 

early and total implantation losses, and 

decreased fetal weights. 

NOAEL: 12.8 mg /kg/day

Mutagenicity

870.5100

Bacterial Reverse 

Mutation Test (Rat)

MRID 40631103

Acceptable

S. typhimurium strains TA98, 

TA100, TA1535, TA1537, and 

TA1538 

Positive

870.5300 In Vitro 

Mammalian Cell 

Gene Mutation Test

MRID 40899001

Acceptable

Chinese Hamster Ovary K1-BH4

(CHO) Cells

Positive

870.5550 

Unscheduled DNA 

Synthesis in 

Mammalian Cell 

Culture

MRID 40631101

Acceptable 

Rat hepatocyte cultures Negative

870.5900

In Vitro Sister 

Chromatid 

Exchange Assay

MRID 40631102

Acceptable 

Chinese Hamster Ovary Cells Negative

Adapted from RED, Table A4, p. 53

VI. Additional Data Gaps

A multi-generation reproduction study, 90-day inhalation toxicity study, and combined chronic 

toxicity/carcinogenicity study conducted with sodium dimethyldithiocarbamate were identified 

as data gaps and are anticipated to be required studies for an adequate risk characterization. 

Structure activity relationship (SAR) analysis may be used to address the cancer study concern. 

If the industry is interested in the SAR approach, a complete and valid SAR analysis should be 

submitted by the registrant, and the Agency will consider the validity of the approach.

An in vivo mutagenicity study such as an erythrocyte micronucleus assay is anticipated to be 

required.

An immunotoxicity study is a data requirement for all antimicrobial pesticide chemicals under 40 

CFR Part 158W, Data Requirements for Antimicrobial Pesticides. The registrant can address 

this data requirement by submitting a study according to the OCSPP 870.7800 guideline, citing 

information from the scientific literature that addresses immunotoxicity of DDC salts, or 

submitting a request for waiver of this study using the Agency’s published guidance, available 

at: http://www.epa.gov/pesticides/regulating/part158-tox-data-requirement.pdf.
Page 50 of 70

References for Appendix A

US EPA, 2009. Hazard Assessment for the Reregistration Eligibility Decision (RED) Document 

of Sodium Dimethyldithiocarbamate and Potassium Dimethyldithiocarbamate. February 5, 

2009 
Page 51 of 70

Appendix B Environmental Fate

NaDDC and KDDC salts are active ingredients in antimicrobials that can be used as material 

preservatives in water systems (air washer, reverse osmosis, and industrial), 

commercial/industrial cooling water, industrial wastewater, pulp/paper mills, gas and oil (drilling 

muds/packer fluids, recovery injection water, fracturing fluids, workover and completion fluids), 

flue gas desulfurization thickeners in smokestacks at coal-fired power plants, and sugar mills 

(cane and beet).

The half-lives in environmental fate studies indicate that both parent NaDDC and its degradates 

can reach WWTPs where they will be associated with water instead of sludge based on their 

water solubilities (260,000-1.63 million mg/l)22, log Kow values (-0.38-1.94) of less than 3, and 

limited sorption to soil (Koc values of 312-445 ml/g)

23. Although the half-lives for NaDDC and 

its degradates in water are relatively short (ranging up to 6.7 days), these estimates of persistence 

are not short enough to prevent residues from entering WWTPs. Data on the half-life of NaDDC

and its degradates in environmental media do not provide specific information on the potential 

for these compounds to be removed during the wastewater treatment process in which conditions 

are present that tend to promote removal of chemical substances from WWTPs, particularly via 

processes such as biodegradation and sorption.

24 Table B1 and Table B2 contain the chemical, 

physical, and environmental fate properties of the DDC salts and degradates.

Abiotic

Hydrolysis

Parent NaDDC is composed of DMA and CS2 moieties. When hydrolyzed it forms DMA, CS2,

a re-combination of DMA and CS2 called TMTU, TMTDS, which is also known as thiram, and 

TMTMS. A hydrolysis study25 in buffered aqueous solutions demonstrated that abiotic 

hydrolysis of NaDDC is pH dependant. The rate of hydrolysis and the relative amounts of major 

degradates DMA and CS2 increased with decreasing pH. Hence acidic conditions will favor the 

decomposition of the DDC anion into DMA and CS2. Formation of oxidative degradates such as 

the disulfide appears to be more predominant in alkaline as opposed to acidic or neutral 

conditions. The estimated abiotic hydrolysis half-lives of NaDDC are 16.5 min, 29.4 hours and 

42.8 days at pH 5, 7 and 9, respectively. 

Photodegradation

A registrant-submitted study for photodegradation of NaDDC in water26 did not track 

degradates. The photolytic half-lives at pH 5, 7 and 9 were 26 minutes, 17.6 hours and 21.2 

hours, respectively. Two degradation products were observed in all samples and a third 

 22 http://www.epa.gov/opptintr/exposure/pubs/episuite.htm 23 MRID 00164056 24 MRIDs 43180801, 40220701, 40365701, and 40365702 25 MRID 43180801 26 835.2240, MRID 40220701
Page 52 of 70

degradate was observed in all pH 7 and pH 9 samples. Though these degradates were not 

identified , the photodegradation in water study is satisfied with the combination of MRIDs 

40220701 and 4565120127, which is an acceptable study for the active ingredient Thiram. 

Thiram is a dimer of the DDC acid and therefore any degradates present are expected to be the 

same as for NaDDC. In MRID 45651201, parent Thiram photodegraded in water with a half-life 

of 6.6 hours and formed four degradates that reached significant (>10 % of applied parent 

Thiram) concentrations. Three of the four degradates were intact Thiram dimers with 

substitutions of oxygen for sulfur and additions of oxygens to sulfur. Thiram sulfone (addition 

of two oxygen molecules) reached up to 31 % of applied parent compound by 24 hours (end of 

study). Thiram oxo (oxygen substituted for a sulfur) reached 11 % of applied parent compound 

by 24 hours. Thiram oxo sulfone (both oxo and sulfone groups) reached up to 15.3 % by 12 

hours and decreased to 9 % by 24 hours. The fourth degradate was a mixture of sulfonic acid 

monomers of DDC in either an oxo form or a thio (sulfur-containing) form. The sum of these 

sulfonic acid degradates increased to 17-21 % of applied thiram by 24 hours. Table B2 below 

contains the chemical and physical properties of these four degradates. No additional data are 

anticipated to be required.

Data on photodegradation on soil28 were not submitted for either NaDDC or KDDC salts. 

However, acceptable data on photodegradation on soil were submitted in MRID 45724501 for 

the active ingredient Thiram. The half-lives of parent Thiram were 0.72 days for the irradiated 

treatment and 1.78 days for the dark control treatment, with a dark-control adjusted half-life of 

1.2 days. CO2 was the only significant (formed at >10 % of applied Thiram) degradate. The 

only current use that requires photodegradation on soil data is wood preservation, and that use is 

expected to be cancelled. No additional data are expected to be required.

Soil Adsorption/Desorption (Kd) and Octanol-Water Partition Coefficient (Koc)

In an adsorption/desorption study29 on agricultural soils, the change in concentration of an 

aqueous NaDDC solution was determined for four soil types: Plainfield sand, California sandy 

loam, Plano silt loam and Hagerstown silty clay loam. At approximately 25°C adsorption values 

(Kd) were observed to be 6.0, 12.6, 6.5 and 1.45 mL/g, respectively. Corresponding Koc values 

were 343, 367, 445 and 312 mL/g, respectively. Desorption of adsorbed DDC salts generally 

ranged from 0-25% but no desorption values were calculated. Sorption of DDC salts to soil 

particles increases with increasing organic carbon (OC) content (r2 = 0.98) and pH (r2 = 0.56).

No additional data are anticipated to be required.

Sludge Adsorption/Desorption

No data on sludge sorption (OCSPP GLN 835.1110) have been submitted. Sorption to sludge is 

not a likely route of dissipation because the log Kow is less than three (3). Therefore data are not 

anticipated to be required. 30

 27 45651201, 835.2240 28 835.2410

29 835.1230, MRID 00164056 30 Final 158 W regulations, 40 CFR Part 158.2282, test note 19, at 78 FR 26991.
Page 53 of 70

Biotic

Aquatic Metabolism

Aerobic and anaerobic aquatic metabolism also degrade NaDDC. In an aerobic aquatic 

metabolism study (MRID 40365701), rapid degradation of NaDDC was observed with an 

estimated half-life of 6 days. Three major unidentified degradates (Peaks A, B, & C) which are 

most likely to be TMTMS, TMTDS, and TMTU, respectively, were detected using high 

performance liquid chromatography (HPLC). Under anaerobic conditions, NaDDC degraded 

into the same three degradates as seen under aerobic metabolism with TMTDS being the major 

degradate identified. Non-linear half lives for TMTDS and TMTMS were 67 days and 15 days, 

respectively under the conditions of the study. Complete mineralization of the parent compound 

was evident under both aerobic and anaerobic conditions as indicated by the amount of carbon 

dioxide (CO2) formed, 38% and 36%, respectively. No additional data are anticipated to be 

required.

Soil Metabolism

No aerobic soil metabolism data were submitted for parent NaDDC. However, an acceptable 

aerobic soil metabolism study (MRID 43734901) was submitted for Thiram which degraded with 

a non-linear half-life of 2.1 days in sandy loam soil. TMTU, TMU, TMTM, and CS2 were minor 

(<10 % of applied Thiram) degradates. Evolved CO2 accounted for 9.0% of the applied 

radioactivity at 2 days post-treatment and increased to a maximum of 75% by 205 days. The 

DT50, DT75, and DT90 for thiram were approximately 1.7, 4.8, and 9.8 days, respectively. No 

additional data are anticipated to be required for parent NaDDC.

The Agency also received registrant- submitted aerobic soil metabolism (OCSPP GLN 835.4100, 

MRID 43685901) and aerobic aquatic metabolism (OCSPP GLN 835.4300, MRID 43685902)

studies for DEA, a surrogate compound for the degradate DMA. The half-lives of DEA in the 

studies were 1.7 and 11 days, respectively. No major degradates were formed in the studies. 

While DEA is an appropriate surrogate compound for DMA, there is no record of review for 

these studies. These studies will be formally reviewed prior to the risk assessment. Until these 

studies are reviewed and classified as appropriate for use in the risk assessment, they are 

included as anticipated data requirements.

Terrestrial Field Dissipation

Data on terrestrial field dissipation (OCSPP GLN 835.6100) were not submitted for either 

NaDDC or KDDC salts. The Agency has reviewed the need for these data and determined that 

the aerobic soil metabolism half-life of approximately two days indicates limited potential for 

leaching to ground water or runoff to surface water. No additional data are anticipated to be 

required.
Page 54 of 70

Leaching from Treated Wood

Data on leaching from treated wood were not submitted for either NaDDC or KDDC salts. This 

study is anticipated to be required. The preferred methods are AWPA E11-06 and E20-06 (see 

justification below). However, the only current use that requires data for leaching from treated 

wood is wood preservation, and that use is expected to be cancelled. If the use in wood 

preservation is cancelled, then this data requirement will no longer likely be needed.

Metabolism in Sewage Sludge and Activated Sludge Respiration Inhibition (ASRI)

No data on ASRI or on degradation in sewage sludge have been submitted but are anticipated to 

be required. The results of the ASRI test determine which of four tests are required and 

determines the extent of impacts to WWTP organisms. If the ASRI test EC50 is equal to or less 

than 20 mg/L, then one of three simulation tests would be anticipated to be required: OCSPP 

GLNs 835.3220, 835.3240, or 835.3280. If the ASRI test IC50 is greater than 20 mg/L, then the 

applicant can choose to conduct a ready biodegradability test (OCSPP GLN 835.3110) or one of 

the three simulation tests (i.e., OCSPP GLNs 835.3220, 835.3240, or 835.3280). Pass criteria for 

the ready biodegradability study are: 70 percent removal of dissolved organic carbon and 60 

percent removal of theoretical oxygen demand or theoretical CO2 production for respirometric 

methods. These pass levels should be reached in a 10-day window within the 28-day period of 

the test. If the antimicrobial passes the ready biodegradability study, then no further testing is 

anticipated to be required. If the antimicrobial fails the ready biodegradability study, then the 

applicant should conduct one of the three biodegradation in activated sludge simulation tests 

mentioned previously.
Docket Number EPA-HQ-OPP-2013-0245

www.regulations.gov

Page 55 of 70

Table B1 – Physical-Chemical and Fate Properties for Sodium and Potassium Dimethyldithiocarbamate Salts and Degradates

Test Guideline

Parent Compounds31 Degradates32

NaDDC KDDC33 Dimethylamine 

(DMA)

Carbon 

disulfide (CS2)

TMTDS 

(Thiram)34 TMTMS35 TMTU36 TMU37

Reference (MRID for 

Parent Compounds 

unless Stated, EPISuite for Degradates)

CAS Number 128-04-1 128-03-0 124-40-3 75-15-0 137-26-8 97-74-5 2782-91-4 632-22-4 EPI-Suite 4.11

Molecular Formula C3 H6 N1 S2 Na1

C3 H6 N1 S2 

K1

C2 H7 N1 C1 S2 C6 H12 N2 S4 C6 H12 N2 S3

C5 H12 N2 

S1

C5 H12 N2 O1 EPI-Suite 4.11

Molecular weight 143.20 159.31 45.08 76.13 240.42 208.36 132.22 116.16 EPI-Suite 4.11

Chemical Structure N/A

Physical-Chemical Properties

Melting Point (oC) N/A38 N/A39 -92.2 -111.5 107 109.5 79.3 -1.2 EPI-Suite 4.11

Boiling Point (oC) 102 >100 6.8 46 339 301.3 245 176.5 EPI-Suite 4.11

Water Solubility 

(mg/L) 1.32 x 106 Easily soluble 1 x 106 2,160 30 1 x 106 350,000 1 x 106 EPI-Suite 4.11

Dissociation Constant 

in Water (pKa) 7.2 7.2 No data No data No data No data No data No data 41609403EPI-Suite 4.11

Octanol-water Partition 

Coefficient (Log Kow) -2.41

(EPI-Suite 4.1)

-1.43

(EPI-Suite 

4.1)

-0.38 1.94 1.73 0.75 0.49 0.19 EPI-Suite 4.11

 31 Chemical and physical properties of parent compounds relative to environmental risk assessment are listed in Table 4 above. Values in this Table B1 are 

copied from Table 4.

32 Major degradates were formed at >10 % of applied parent compound. Minor degradates were formed at <10 % of applied parent compound. 33 Environmental fate data were submitted for NaDDC but not KDDC. Both compounds are salts and therefore will readily disassociate in water to form the Na 

or K cations and the DDC anion. As a result, NaDDC is an acceptable surrogate for KDDC. 34 DDC anion forms a cross-linked dimer TMTDS, which is joined by two (2) sulfur molecules. This dimer is the active ingredient Thiram (PC Code 079801). 35 Cross-linked DDC anions joined by one (1) sulfur instead of two sulfurs. 36 Tetramethyl thiourea (TMTU) 37 Tetramethyl urea (TMU) 38 Not applicable 

39 Not applicable
Page 56 of 70

Test Guideline

Parent Compounds31 Degradates32

NaDDC KDDC33 Dimethylamine 

(DMA)

Carbon 

disulfide (CS2)

TMTDS 

(Thiram)34 TMTMS35 TMTU36 TMU37

Reference (MRID for 

Parent Compounds 

unless Stated, EPISuite for Degradates)

Koc (ml/g) 312-445 No data40 4.7 48 676 337.3 25.7 8.6 00164056

EPI-Suite 4.11

Soil adsorption/ 

desorption (ml/g) 1.5-12.6 No data41 3.2 No data No data No data No data No data 00164056EPI-Suite 4.11

Sludge adsorption/ 

desorption (%) <1.9 <1.9 1.74 0.6 1.6 1.5 0.63 0.62 EPI-Suite 4.11

Bioconcentration 

Factor (BCF) No data No data 3.2 8.9 6.4 3.2 3.2 3.2 EPI-Suite 4.11

Vapor Pressure (mm 

Hg) 4.2 x 10-9 8.2 x 10-10 1.5 x 10+3 359 1.7 x 10-5 2.7 x 10-4 1.1 x 10-2 1.4 x 10+1 EPI-Suite 4.11

Henry’s Law Constant

(atm-m3/mole) 7.9 x 10-16 2.0 x 10-16 4.5 x 10-5 1.2 x 10-2 3.8 x 10-10 8 x 10-10 5.2 x 10-9 5.0 x 10-5 EPI-Suite 4.11

Abiotic Degradation Half-lives (days unless specified)

Hydrolysis 

835.2120

17 min (pH 5)

29 hours (pH 7)

43 days (pH 9)

No data Stable, did not 

decline Stable Minor degradate Minor Not formed Not formed 43180801

Photodegradation in 

water 

835.224042

3 hours (pH 5)

2.1 days (pH 7)

1.7 days (pH 9)

No data No data No data No data No data No data No data 40220701

Photodegradation in 

water

835.224043

for Thiram

No data No data No data No data

6.6 hours 

(parent 

compound)

No data No data No data 45651201

Photodegradation on 

soil 

835.241043,

for Thiram

No data No data No data No data 1.2 days (parent 

compound) No data No data No data 45724501

 40 Data for NaDDC were used as a surrogate for KDDC 41 Data for NaDDC were used as a surrogate for KDDC 42 Unknown degradate was formed at up to 22-28 % of applied parent compound by 19 minutes, and declined to 1.4-3.3 % by 77 minutes. The 5/14/2009 

environmental fate memorandum required another photodegradation in water study.

43 Thiram data used as a surrogate for NaDDC and KDDC
Page 57 of 70

Test Guideline

Parent Compounds31 Degradates32

NaDDC KDDC33 Dimethylamine 

(DMA)

Carbon 

disulfide (CS2)

TMTDS 

(Thiram)34 TMTMS35 TMTU36 TMU37

Reference (MRID for 

Parent Compounds 

unless Stated, EPISuite for Degradates)

Biotic Degradation Half-lives (days unless specified)

Aerobic soil 

metabolism 

835.4100

for Thiram

No data No data

No major 

degradate 

formed

No major 

degradates 

formed

2.1 days

(parent 

compound)

No major 

degradates 

formed

No major 

degradates 

formed

No major 

degradates 

found

43734901

Aerobic soil 

metabolism for 

diethanolamine 

(DEA)44

835.4100

No data No data 1.7 day 

(diethanolamine)

No major 

degradates 

formed

No major 

degradates 

formed

No major 

degradates 

formed

No major 

degradates 

formed

No major 

degradates 

formed

43685901

Anaerobic soil 

metabolism

835.4200

Not submitted Not 

submitted Not submitted Not submitted Not submitted Not submitted Not 

submitted Not submitted Not applicable

Aerobic aquatic 

metabolism 

835.4300

5.6 days No data Not formed Not formed 7 days Stable, did not 

decline

24 % at day 

zero, <4.3 % 

after

Not formed 40365702

Aerobic aquatic 

metabolism of 

Diethanolamine45

835.4300

No data No data 7 days 

(diethanolamine)

No major 

degradates 

formed

No major 

degradates 

formed

No major 

degradates 

formed

No major 

degradates 

formed

No major 

degradates 

formed

43685902

Anaerobic aquatic 

metabolism

835.4400

Not submitted Not 

submitted Not submitted Not submitted Not submitted Not submitted Not 

submitted Not submitted Not applicable

Biodegradation halflife in sludge (days)Not submitted Not 

submitted Not submitted Not submitted Not submitted Not submitted Not submitted Not submitted Not applicable

 44 Aerobic soil metabolism data on diethanolamine (MRID 43685901) were submitted as a surrogate for the dimethylamine (DMA) degradate. 45 Aerobic aquatic metabolism data on diethanolamine (MRID 43685902) were submitted as a surrogate for the dimethylamine (DMA) degradate.
Page 58 of 70

Table B2 – Physical-Chemical and Fate Properties for Degradates of Sodium and Potassium Dimethyldithiocarbamate Salts

from Photodegradation in Water46

Test Guideline Thiram sulfone Thiram oxo Thiram oxo sulfone

DDC sulfonic 

acid monomer 

(oxo)

DDC sulfonic acid 

monomer (thio)

Reference (MRID for 

Parent Compounds unless 

Stated, EPI-Suite for 

Degradates)

CAS Number None None None None None EPI-Suite 4.11

Molecular Formula C6H13N2S4 C6H12N2OS3 C6H18N2O3S3 C6H7NO4S C6H7NO3S2 EPI-Suite 4.11

Molecular weight 241.42 224.36 262.40 153.15 169.21 EPI-Suite 4.11

Chemical Structure 45651201

Melting Point (oC) 190.38 110.35 155.43 101.39 98.02 EPI-Suite 4.11

Boiling Point (oC) 452.44 344.70 428.80 325.94 320.06 EPI-Suite 4.11

Water Solubility (mg/L) 1 x 106 4.41 x 104 1 x 106 1 x 106 1 x 106 EPI-Suite 4.11

Dissociation Constant in Water

(pKa) N/A N/A N/A N/A N/A EPI-Suite 4.11

Octanol-water Partition 

Coefficient (Log Kow) -2.5 1.03 -1.58 -3.14 -2.47 EPI-Suite 4.11

Koc (ml/g) 113.5 57.02 16.9 7.7 1 EPI-Suite 4.11

Soil adsorption/ desorption

(ml/g) No data No data No data No data No data EPI-Suite 4.11

Sludge adsorption/ desorption

(%) 1.75 1.80 1.75 1.75 1.75 EPI-Suite 4.11

Bioconcentration Factor (BCF) 3.16 2.21 3.16 3.16 3.16 EPI-Suite 4.11

Vapor Pressure (mm Hg) 7.9 x 10-9 2.55 x 10-5 1.85 x 10-10 4.55 x 10-6 7.22 x 10-6 EPI-Suite 4.11

Henry’s Law Constant

(atm-m3/mole) 2.51 x 10-15 1.71 x 10-10 6.38 x 10-17 9.17 x 10-13 1.61 x 10-12 EPI-Suite 4.11

Abiotic Degradation Half-lives (days unless specified)

Hydrolysis 

835.2120 No data No data No data No data No data No data

 46 Based on MRID 45651201, Photodegradation in water study for Thiram, a dimer of DDC acid.
Page 59 of 70

Test Guideline Thiram sulfone Thiram oxo Thiram oxo sulfone

DDC sulfonic 

acid monomer 

(oxo)

DDC sulfonic acid 

monomer (thio)

Reference (MRID for 

Parent Compounds unless 

Stated, EPI-Suite for 

Degradates)

Photodegradation in water 

835.224047 Stable, did not decline Stable, did not decline

Stable, did not 

decline Slight decline Slight decline 45651201

Photodegradation on soil 

835.2410 No data No data No data No data No data Not applicable

Biotic Degradation Half-lives (days unless specified)

Aerobic soil metabolism for 

diethanolamine (DEA)48

835.4100

Not formed Not formed Not formed Not formed Not formed 43685901

Aerobic soil metabolism 

835.4100 No data No data No data No data No data Not applicable

Anaerobic soil metabolism

835.4200 No data No data No data No data No data Not applicable

Aerobic aquatic metabolism 

835.4300 No data No data No data No data No data Not applicable

Aerobic aquatic metabolism of 

Diethanolamine49

835.4300

Not formed Not formed Not formed Not formed Not formed 43685902

Anaerobic aquatic metabolism

835.4400 No data No data No data No data No data Not applicable

Biodegradation half-life in 

sludge (days) No data No data No data No data No data Not applicable

 47 Unknown degradate was formed at up to 22-28 % of applied parent compound by 19 minutes, and declined to 1.4-3.3 % by 77 minutes. The 5/14/2009 

environmental fate memorandum required another photodegradation in water study. 48 Aerobic soil metabolism data on diethanolamine (MRID 43685901) were submitted as a surrogate for the dimethylamine (DMA) degradate.

49 Aerobic aquatic metabolism data on diethanolamine (MRID 43685902) were submitted as a surrogate for the dimethylamine (DMA) degradate.
Page 60 of 70

Appendix C Ecotoxicology Profile

Toxicity to Terrestrial Receptors

Avian acute-oral and dietary

Avian acute-oral and dietary toxicity data for the northern bobwhite (Colinus virginianus) and 

mallard (Anas platyrhynchos) categorize both DDC salts as being slightly to practically nontoxic 

to birds. Thiram, a degradate, is slightly to practically nontoxic based on acute-oral and dietary 

toxicity data for the northern bobwhite (C. virginianus) and mallard (A. platyrhynchos), Japanese 

quail (Coturnix japonica) and ring-necked pheasant (Phasianus colchicus). There are two avian 

reproduction studies with thiram, one with the northern bobwhite (C. virginianus) and one with 

the mallard (A. platyrhynchos). No additional avian data are anticipated to be required. 

Avian Toxicity of Sodium and Potassium DDC Salts and Degradate

Study Type Species Test material

(% ai) Toxicity Toxicity Classification MRID & Status

Acute – Avian 

Oral

GLN 850.2100

Northern 

bobwhite

NaDDC (40)

LD50: 391 mg a.i./kgbw/day

(991mg ts/kg-bw/day)

Moderately toxic 00159788

Acceptable

KDDC (50)

LD50: 627 mg a.i./kgbw

(1255mg ts/kg-bw/day)

Slightly toxic 00105155 

Acceptable

Mallard Thiram (99) LD50: >2800 mg/kgbw/day

Practically 

nontoxic

00160000 

Acceptable

Red-winged 

black bird Thiram (99) LD50: >100 mg/kgbw/day Unknown 00073683Supplemental

Ring-necked 

pheasant Thiram (99) LD50: 673 mg/kgbw/day Slightly toxic 00160000Supplemental

Starling Thiram (95) LD50: >5000 mg/kgbw/day

Practically 

nontoxic

00022923

Acceptable

Subacute –

Avian Dietary

GLN 850.2200

Northern 

bobwhite

KDDC (50) LC50: >2600 ppm a.i. 

(>5200 ppm ts)

ts Practically 

nontoxic

00109244

Acceptable

NaDDC (40) LC50: >2248 ppm a.i.

(>5620 ppm ts)

ts Practically 

nontoxic

00159786

Supplemental

Mallard

KDDC (50) LC50: >2500 ppm a.i.

(>5000 ppm ts)

ts Practically 

nontoxic

00105156

Acceptable

NaDDC (38.9) LC50: >2475 ppm a.i.

(>6363 ppm ts)

ts Practically 

nontoxic

42561802

Acceptable

NaDDC (40) LC50: 1874 ppm a.i.

(4688 ppm ts) ts Slightly toxic 00159787Supplemental

Thiram (95) LC50: 3950 ppm Slightly toxic 00022923

Supplemental

Thiram (95) LC50: 5000 ppm Slightly toxic 00022923

Supplemental

Japanese quail Thiram (95) LC50: >5000 ppm Practically 

nontoxic

00022923

Acceptable

Ring-necked 

pheasant Thiram (95) LC50: >5000 ppm Practically nontoxic

00022923

Acceptable

Reproduction –

Avian

Northern 

bobwhite Thiram (97.5) NOAEL: 500 ppm NA 43612502Acceptable
Page 61 of 70

Study Type Species Test material

(% ai) Toxicity Toxicity Classification MRID & Status

GLN 850.2300

Mallard

Thiram (97.5) NOAEL: 9.6 ppm NA 45441201

Acceptable

Thiram (97.5) NOAEL <50 ppm NA 43612501

Supplemental

ts: test substance

Beneficial Insects

No data are available for the DDC salts, there is an acute dermal contact study with the degradate 

thiram. Data (OCSPP GLNs 850.3020, 850.3030) are expected to be required for the wood 

preservative use of the DDC salts. If the use in wood preservation is cancelled, then this data 

requirement will no longer likely be needed.

Species, Age or size % Purity

Design

Exposure Type/

pH/ hardness/

temperature

Endpoint Toxicity 

Category MRID & Status

Honey bee (Apis 

mellifera), N.R.

GLN 850.3020

Thiram 

Tech Dermal contact 48-h LD50 = 74 μg/bee Slightly toxic 00036935Supplemental

Toxicity to Aquatic Receptors

Freshwater Fish, acute

Acute toxicity data for freshwater fish are available for rainbow trout (Oncorhynchus mykiss), 

bluegill (Lepomis macrochirus), and fathead minnow (Pimephales promelas). The potassium 

DDC salt is categorized as being highly to very highly toxic and the sodium DDC salt as slightly 

to moderately toxic. The combination of sodium DDC salt and Nabam is moderately toxic, and 

thiram, a degradate, is very highly toxic. No additional data are anticipated to be required.

Freshwater Fish Acute Toxicity of Sodium and Potassium DDC Salts and Degradate

Study Type Species Test material

(% ai)

Toxicity

(μg ai/L)

Toxicity 

Classification

MRID & 

Status

Acute -

Freshwater Fish

GLN 850.1075

Rainbow trout 

NaDDC (40.9) 96-hr LC50: 6700 Moderately toxic 42247901 

Acceptable

NaDDC (15) and 

Nabam (15)

96-hr LC50: 1700 

(as formulation) Moderately toxic 00104057Supplemental

KDDC (50) 96-hr LC50: 360 Highly toxic 00134589 

Acceptable

Thiram (99) 96-hr LC50: 126 Highly toxic

McCann 1976 

Test Number 

1001

Acceptable

Thiram (99) 96-hr LC50: 46 Highly toxic 46249301

Supplemental

Thiram (75) 96-hr LC50: 320

(as formulation) Highly toxic Supplemental
Page 62 of 70

Study Type Species Test material

(% ai)

Toxicity

(μg ai/L)

Toxicity 

Classification

MRID & 

Status

Bluegill 

sunfish

NaDDC (40.5) 96-hr LC50: 38,500 Slightly toxic 42504801

Acceptable

NaDDC (15) and 

Nabam (15)

96-hr LC50: 3400

(as formulation) Moderately toxic 00104057Supplemental

Thiram (99) 96-hr LC50: 42 Very highly 

toxic

00070801

Acceptable

Thiram (75) 96-hr LC50: 280

(as formulation) Highly toxic 00090294Supplemental

Fathead 

minnow KDDC (50) 96-hr LC50: 60 Very highly toxic

ACC240946

Acceptable

Harlequin fish Thiram (80) 

formulation 96-hr LC50: 7 Very highly toxic

05020144

Supplemental

Freshwater Fish, chronic

No data are available for the DDC salts. However, a flow-through life-cycle toxicity test with the 

fathead minnow (Pimephales promelas) is available for thiram. Time to hatch of the F1 

generation and 4-week survival of the F1 generation were as sensitive as reproductive effects 

(reduced egg production and reduced spawning frequency). An early-life stage study (850.1400) 

with the DDC salts is anticipated to be required for assessing chronic risk to fish. For thiram, as 

the more sensitive acute fish was the bluegill sunfish, an acute-to-chronic ratio (ACR) method 

was used to calculate a chronic value for the bluegill sunfish. The Web-based Interspecies 

Correlation Estimation (Web-ICE50), version 3.2.1, application was first used to estimate acute 

toxicity of thiram to the fathead minnow from existing rainbow trout and bluegill sunfish data 

(results are provided at the end of this appendix). Web-ICE predicted a fathead minnow acute 

value for thiram 140 ppb based on the rainbow trout data; the rainbow trout correlation was used 

because it has a higher correlation than that for the bluegill sunfish, Comparing this fathead 

minnow acute value to the NOAEC from the fathead minnow full life cycle study provides an 

ACR of 127. Applying this ACR to the rainbow trout acute data provides an estimated NOAEC 

of 0.36 ppb thiram.

Freshwater Fish Chronic Toxicity of Thiram

Study Type Species Test material

(% ai)

Toxicity

(μg ai/L) Endpoints MRID & Status

Chronic –

Freshwater Fish

GLN 850.1500

Fathead

minnow Thiram (98.7) NOAEC = 1.1

LOAEC = 2.2

F0 egg production; F0 % 

spawning frequency; F1

4-week survival; F1 time 

to hatch 

47824101

Acceptable

 50 http://epa.gov/ceampubl/fchain/webice/
Page 63 of 70

Freshwater Invertebrates, acute

Acute toxicity data for the water flea (Daphnia magna) categorize the sodium DDC salt as being 

very highly toxic and the potassium DDC salt as highly toxic. The degradate Thiram also is 

highly toxic. No additional data are anticipated to be required.

Freshwater Invertebrate Acute Toxicity of Sodium and Potassium DDC Salts and 

Degradate

Study Type Species Test material

(% ai)

Toxicity

(μg ai/L)

Toxicity 

Classification

MRID & 

Status

Acute –

Freshwater 

Invertebrate

GLN 850.1010

Water flea 

NaDDC (40.5) 48-hr EC50: 52 Very highly 

toxic

42504802 

Acceptable

KDDC (50) 48-hr EC50: 340 Highly toxic 00105154 

Acceptable

Thiram (98) 48-hr EC50: 210 Highly toxic 00164662

Acceptable

Freshwater Invertebrates, chronic

No data are available for the DDC salts. However, a thiram chronic study (MRID 47495001) is 

currently under review. A life cycle study (850.1300) is anticipated to be required for assessing 

chronic risk to aquatic invertebrates with the DDC salts. 

Estuarine/Marine Fish and Invertebrates

Acute data are available for fish (sheepshead minnow, Cyprinodon variegatus) and the following 

invertebrates: Eastern oyster (Crassostrea virginica), mysid shrimp (Mysidopsis bahia), blue 

crab (Callinectes sapidus), and grass shrimp (Palaemonetes pugio). The data categorize sodium 

DDC salt as slightly toxic to fish and as highly to very highly toxic to invertebrates. The 

combination of sodium DDC salt and Nabam is moderately to very highly toxic. The degradate 

thiram is highly to very highly toxic. No additional data are anticipated to be required.

Estuarine/marine Acute Toxicity of Sodium DDC Salt and Degradate

Study Type Species Test material

(% ai)

Toxicity

(μg ai/L)

Toxicity 

Classification

MRID & 

Status

Acute –

Saltwater Fish

GLN 850.1075

Sheepshead 

minnow

NaDDC (48.3) 96-hr LC50: 

59,000 Slightly toxic 41984701 

Acceptable

NaDDC (16) and 

Nabam (15)

96-hr LC50: 122

(as ts) Highly toxic 00100706 

Acceptable

Thiram (98) 96-hr LC50: 540 Highly toxic 42514401

Acceptable

Acute –

Saltwater 

Invertebrate

GLNs 

850.1025/1055

850.1035

Eastern oyster

NaDDC (39.6) 96-hr EC50: 760 Highly toxic 42561902 

Acceptable

NaDDC (16) and 

Nabam (15)

96-hr EC50: 300

(as ts) Highly toxic 00100704

Supplemental

Thiram (98.3)

IC50 = 4.7

(embryo/larval 

development)

Very highly 

toxic

42488301

Acceptable
Page 64 of 70

Study Type Species Test material

(% ai)

Toxicity

(μg ai/L)

Toxicity 

Classification

MRID & 

Status

Mysid

NaDDC (39.6) 96-hr LC50: 88 Very highly 

toxic

42561901

Acceptable

Thiram (98.3) LC50: 3.36 Very highly 

toxic

42488302

Acceptable

Grass shrimp NaDDC (16) and 

Nabam (15)

LC50: 17

(as ts)

Very highly 

toxic

00100705 

Supplemental

Blue crab NaDDC (16) and 

Nabam (15)

LC50: 9100

(as ts) Moderately toxic 00100703

Supplemental

ts: test substance

Aquatic and terrestrial plants

Plant toxicity data are anticipated to be required for the DDC salts uses. Testing for aquatic 

plants is conducted with one species of aquatic vascular plant (duckweed, Lemna gibba) and four 

species of algae: (1) freshwater green alga, Selenastrum capricornutum, (2) marine diatom, 

Skeletonema costatum, (3) freshwater diatom, Navicula pelliculosa, and (4) bluegreen 

cyanobacteria, Anabaena flos-aquae. A seedling emergence test (OCSPP GLN 850.4100) also is 

anticipated to be required for rice (Oryza sativa), representing a rooted aquatic macrophyte. 

Data are not available for the DDC salts. Green algae and duckweed data are available for 

thiram.

A vegetative vigor study (OCSPP GLN 850.4150) is anticipated to be required to support an 

assessment of risk from exposure to residual biocides in waste water used for irrigation and from 

uses resulting in spray drift. Use patterns, such as the oil and gas uses, have the potential for 

waste water from the process to be used in irrigation. There are no vegetative vigor data for 

thiram or DDC salts. Uses that potentially result in spray drift, such as an anti-sapstain spray 

application, may result in exposure of non-target plants.

Aquatic Plants

Test Species Test Material

(% ai)

Toxicity Endpoint

(μg ai/L)

EPA Study

ID

Aquatic plants – vascular

Duckweed, Lemna gibba

GLN 850.4400

Thiram (98.7%) IC50 = 1,600,000

NOAEC < 57,000

45441202

Acceptable

Aquatic plants - green algae,

Selenastrum capricornutum

GLN 850.4500

Thiram (99%)

IC50 = 45

NOAEC < 57 (will 

calculate IC05)

42646001

Acceptable

Thiram (99%) IC50 = 140

IC05 = NR

44086101

Acceptable

Mesocosm

A mesocosm study was conducted to simulate the potential impact of Thiram 80 WG (a water 

dispersible formulation containing 81.2% of the a.i. Thiram) contamination via spray drift from 

agricultural applications on a freshwater ecosystem under field conditions. There were seven 

treatment levels consisting of nominal Thiram 80 WG concentrations of 1.25, 4.0, 12.5, 40, 125, 
Page 65 of 70

400, and 1250 ppb Thiram 80 WG, which correspond to 1.0, 3.2, 10, 32, 100, 320, and 1000 ppb 

a.i. The mesocosm study design included three replicate mesocosm ponds for the negative 

control group and a single replicate mesocosm pond per treatment group. Four applications, 

simulating direct over-spray or spray drift, were made at 7-day intervals with identical 

application rates. Thiram quickly degraded in the water/sediment systems with a half-life 

ranging from 0.7 to 1.9 days.

In general, phytoplankton (at the community level) taxa abundance, diversity (based on the 

Shannon-Weaver index), evenness, and similarity (Steinhaus' and Stander's similarity indices) 

were reported to be significantly reduced during the treatment period at the two highest treatment 

levels tested; i.e, nominal 320 and 1000 ppb a.i. No significant treatment-related reductions in 

any individual phytoplankton taxa were meaningfully identified during the treatment period. 

However, these significant reductions in the above community parameters were attributed by the 

authors to treatment related reductions in zooplankton grazers and the subsequent rapid 

population growths, as supported by significant phytoplankton biomass, of those phytoplankton 

taxa with the most rapid population development/growth rates at the nominal 320 and 1000 ppb 

a.i. Therefore, true treatment-related negative effects as a result of Thiram 80 WG application on 

the phytoplankton community can be excluded with high probability at least up to and including 

the nominal 100 ppb a.i. treatment level. Consequently, the NOAEC for individual 

phytoplankton taxa and the community as a whole was concluded to be 106.5 ppb a.i. (measured; 

nominally 100 ppb a.i.). Periphyton biomass was significantly reduced also at the nominal 320 

and 1000 ppb a.i. treatment levels. Treatment-related effects on specific taxa were never 

discussed within the study report.

Due to the significant negative concentration-effect relationship in zooplankton taxa abundance 

during the treatment period, the NOAEC for zooplankton taxa abundance was 2.1 ppb a.i. 

(measured; nominally 3.2 ppb a.i.). Zooplankton community diversity (based on ShannonWeaver 

Index) and evenness were not significantly affected during the treatment period. Similarity 

analysis of the treated zooplankton communities was compared to the control ponds using 

Steinhaus' and Stander's indices. The NOAEC value for zooplankton community similarity 

during the treatment period was <1.0 ppb a.i. (measured; nominally <1.0 ppb a.i.); i.e. less than 

the lowest treatment concentration tested.

Test material concentrations were not measured in all treatment ponds following each application 

and did not allow for an exact determination of what concentrations the mesocosm flora and 

fauna were exposed. The overall short duration of the study, less than 1 year for the in-life 

portion of the study, also prevented the assessment of chronic effects of Thiram 80 WG and did 

not allow for the comparison of the treated community structure compared to the structure from 

untreated or post-treatment years. This study provides only supplemental data because only five 

of the seven treatment levels were actually analytically verified during the study and because this 

study does not fulfill any current US EPA OPP guideline requirement. Additionally there was no 

true replication of treatment levels. Conclusions, provided in this study may be useful for 

characterization.
Page 66 of 70

Test Species

Test 

Material

(% ai)

Toxicity Endpoint EPA Study

ID

Mesocosm: Multiple 

species

Non-Guideline

Thiram 80 

WG

(80)

Zooplankton community similarity NOAEC < 1.0 

ppb a.i.

Hexarthra mira/intermedia NOAEC was < 1.0 ppb 

a.i. (measured)

Supplemental

WebICE Results for Estimating Fathead 

Minnow Acute using Rainbow Trout

Surrogate Species: Rainbow trout (Oncorhynchus mykiss) 

Predicted Species: Fathead minnow (Pimephales promelas) 

Surrogate Acute Toxicity (log value) Predicted Acute Toxicity (log value) 

46 μg/L 

(1.66)

140.16 μg/L (2.14)

Select Confidence Interval: Lower Limit Upper Limit

 95% 92.35 μg/L 212.71 μg/L

Model Information

Intercept: 0.669768

Slope: 0.888200

Degrees of Freedom (N-2): 79

R2

: 0.825954

p-value: 0.000000

Average value of surrogate (log value): 1077.24 (3.03)

Minimum value of surrogate (log value): 0.671479 (-0.172967)

Maximum value of surrogate (log value): 9800000.00 (6.99)

Mean Square Error (MSE): 0.372276

Sum of Squares (Sxx): 176.91
Page 67 of 70

Cross-validation Success (%): 82.71

Taxonomic Distance: 4

WebICE Results for Estimating Fathead 

Minnow Acute using Bluegill Sunfish

Surrogate Species: Bluegill (Lepomis macrochirus) 

Predicted Species: Fathead minnow (Pimephales promelas) 

Surrogate Acute Toxicity (log value) Predicted Acute Toxicity (log value) 

42 μg/L 

(1.62)

109.55 μg/L (2.03)

Select Confidence Interval: Lower Limit Upper Limit

 95% 66.32 μg/L 180.97 μg/L

Model Information

Intercept: 0.663875

Slope: 0.847538
Page 68 of 70

Degrees of Freedom (N-2): 66

R2

: 0.790938

p-value: 0.000000

Average value of surrogate (log value): 1174.34 (3.06)

Minimum value of surrogate (log value): 0.407815 (-0.389536)

Maximum value of surrogate (log value): 7100000.00 (6.85)

Mean Square Error (MSE): 0.431786

Sum of Squares (Sxx): 150.09

Cross-validation Success (%): 75.00

Taxonomic Distance: 4
Page 69 of 70

Appendix D Product Chemistry

Sodium dimethyldithiocarbamate and Potassium dimethyldithiocarbamate salts product 

chemistry information is summarized in Table E1 (source: MRIDs 41586303, 41609403, 

41651301, 42510401, and 41609407 and EPI Suite v4.1).

Table E1 – Product Chemistry of Sodium and Potassium Dimethyldithiocarbamate Salts

Guideline 

No. 

Physical and Chemical 

Properties

Sodium

dimethyldithiocarbamate

Potassium 

dimethyldithiocarbamate

830.1550 Product identity and 

composition Refer to Table 3. Refer to Table 3.

830.1600 Description of materials used 

to produce the product

Confidential Business Information 

(CBI)

CBI

830.1620 Description of production 

process

CBI CBI

830.1650 Description of Formulation 

Process CBI CBI

830.1670 Discussion of formulation of 

impurities

CBI CBI

830.1700 Preliminary analysis CBI CBI

830.1750 Certified limits CBI CBI

830.1800 Enforcement analytical method Purity of dimethyldithiocarbamate is 

determined by acidic decomposition

Purity of dimethyldithiocarbamate 

is determined by acidic 

decomposition

830.1900 Submittal of samples CBI CBI

830.6302 Color Yellow-green to amber liquid Pale yellowish green liquid.

Clear light amber liquid.

830.6303 Physical State Liquid Liquid

830.6304 Odor Mild characteristic of sulfurcontaining compounds

Mild characteristic of sulfurcontaining compounds.

Slight sulfur odor.

Pungent, ammoniacal odor.

830.6313 

Stability to normal and 

elevated temperature, 

metals/metal ions 

Stable under recommended storage 

conditions.

Stable up to 70 °C for extended 

periods.

Stable under recommended storage 

conditions.

Stable up to 50 ± 2 C for a 30 day 

period.

830.6314

Oxidation/Reduction:

Chemical Incompatibility

Does not contain an oxidizing or 

reducing agent.

Incompatible with strong acids, 

strong oxidizing agents. (40% w/w 

aqueous solution)

Does not contain an oxidizing or 

reducing agent.

Incompatible with strong acids, 

strong oxidizing agents. (50% w/w 

aqueous solution)

830.7000 pH 

As measured 13.3 at 20°C.

10.1 (1% aqueous solution) -HPV

12.6 (32% aqueous solution) -HPV

9-14 (50% solution)
Page 70 of 70

Guideline 

No. 

Physical and Chemical 

Properties

Sodium

dimethyldithiocarbamate

Potassium 

dimethyldithiocarbamate

830.7050 UV/Visible Absorption 

Sodium dimethyldithiocarbamate

was identified by UV/VIS spectra 

recorded at different pH values.

Result at pH < 2:

> 200 nm, ε = 0 l mol-1 cm-1

Result at pH 7:

254 nm, ε = 12792 l mol-1 cm-1

279 nm, ε = 13127 l mol-1 cm-1

295 nm, ε = 1863 l mol-1 cm-1

Result at pH > 11:

254 nm, ε = 13388 l mol-1 cm-1

279 nm, ε = 13687 l mol-1 cm-1

295 nm, ε = 1803 l mol-1 cm-1

Potassium dimethyldithiocarbamate

was identified by UV/VIS spectra 

recorded at different pH values.

Result at pH < 2:

207 nm, ε = 12713 l mol-1 cm-1

Result at pH 7:

253 nm, ε = 26409 l mol-1 cm-1

279 nm, ε = 28187 l mol-1 cm-1

495 nm, ε = 3562 l mol-1 cm-1

Result at pH > 11:

254 nm, ε = 12714 l mol-1 cm-1

279 nm, ε = 13120 l mol-1 cm-1

830.7100 Viscosity 20.2 centipoise (cps) at 20°C 20.2 cps at 20°C

830.7200 Melting point 

Not applicable. It is a liquid.

MP Performed on PAI: > 300 °C 

with decomposition. 

Not applicable. It is a liquid.

MP Performed on PAI: > 300 °C 

with decomposition.

830.7220 Boiling point 

Not required since PAI is solid

Boiling point of 32% solution: 

102°C

Not required since PAI is solid.

Boiling point of 50% solution: 

>100°C

830.7300 Density 1.17 g/ml (40% solution) 1.25 g/ml (50% solution)

830.7370 Dissociation Constant in water 

pKa = 5.4 for the organic portion/ 

Estimated/(40% w/w aqueous 

solution).

6.5 x 10-8 at 20°C. Performed on 

PAI.

pKa value: Not applicable; product 

decomposes below pH 8. – HPV

pKa = 5.4 for the organic portion/ 

Estimated/(40% w/w aqueous 

solution).

6.5 x 10-8 at 20°C. Performed on 

PAI.

830.7520 Particle size, fiber length, & 

diameter distribution 

Not Applicable; soluble in water Not Applicable; soluble in water

830.7550 Partition coefficient (noctanol/water) 

Performed on PAI. Estimated to be 

less than 1 based on solubility at 

20°C.

−2.41 (EPI Suite v4.1)

−1.43 (EPI Suite v4.1)

830.7840 Solubility in water 

Complete

132 g/100 ml of water at 20 °C 

Performed on PAI.

Complete.

Easily soluble in water.

830.7860 Solubility in organic solvents 

Methanol 89 g/100 g at 20°C

Glycol 94 g/100 g at 20°C

Performed on PAI.

Not reported (Not required).

830.7950 Vapor pressure 

Solid: 4.17 x 10-9 mm Hg at 25°C 

(EPI Suite v4.1).

40% w/w as aqueous solution: 

13 mm Hg at 25°C.

Solid: 8.15 x 10-10 mm Hg at 25°C 

(EPI Suite v4.1).