Top Environmental Fate Ecotoxicology Human Health Translations
Home
A to Z: All
A to Z: Insecticides
A to Z: Herbicides
A to Z: Fungicides
A to Z: Other related substances
Search
Support information
Edit history
Purchasing and licensing
Industry collaboration
NEW
User survey
Pyrithiobac-sodium (Ref: DPX PE 350)
Last updated: 21/08/2024
(Also known as: KIH 2031)

SUMMARY
Pyrithiobac-sodium is a post-emergence herbicide. It has a high aqueous solubility, is semi-volatile and, based on its chemical properties, it is very mobile and has high potential to leach to groundwater. It is generally moderately persistent in soil systems but tends to be non-persistent in aquatic systems. It has a low mammalian toxicity but may bioaccumulate. It shows a low to moderate level of toxicity to most biodiversity.
Data alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement.

Environmental fate Ecotoxicity Human health
 
Ecotoxicity
Moderate alert:
Birds acute ecotoxicity: Moderate; Bees acute contact ecotoxicity: Moderate
Human health
Moderate alert:
Possible Carcinogen
Warning:
Significant data are missing
GENERAL INFORMATION
Description
Post-emergence control of broad-leaved weeds in cotton and other crops
Example pests controlled
Cocklebur; Goosefoot; Nightshade; Knotweed; Pigweed; Rocket; Shepherd's purse; Sunflower; velvetleaf; Morning glory; Purslane
Example applications
Cotton
Efficacy & activity
-
Availability status
Current
Introduction & key dates
1995, registered USA
GB regulatory status
GB COPR regulatory status
Not approved
Date COPR inclusion expires
Not applicable
GB LERAP status
No UK approval for use as a pesticide
EC Regulation 1107/2009 (repealing 91/414)
EC Regulation 1107/2009 status
Pending
Dossier rapporteur/co-rapporteur
-
Date EC 1107/2009 inclusion expires
Not applicable
EU Candidate for substitution (CfS)
No
Listed in EU database
Yes
Approved for use (✓) under EC 1107/2009 in the following EU Member States
ATAustria
BEBelgium
BGBulgaria
CYCyprus
CZCzech Republic
DEGermany
DKDenmark
EEEstonia
ELGreece
                 
ESSpain
FIFinland
FRFrance
HRCroatia
HUHungary
IEIreland
ITItaly
LTLithuania
LULuxembourg
                 
LVLatvia
MTMalta
NLNetherlands
PLPoland
PTPortugal
RORomania
SESweden
SISlovenia
SKSlovakia
                 
Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries
ISIceland
NONorway
                 
Additional information
Also used in
Australia
Chemical structure
Isomerism
None
Chemical formula
C₁₃H₁₀ClN₂NaO₄S
Canonical SMILES
COC1=CC(=NC(=N1)SC2=C(C(=CC=C2)Cl)C(=O)[O-])OC.[Na+]
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
CNILNQMBAHKMFS-UHFFFAOYSA-M
International Chemical Identifier (InChI)
InChI=1S/C13H11ClN2O4S.Na/c1-19-9-6-10(20-2)16-13(15-9)21-8-5-3-4-7(14)11(8)12(17)18;/h3-6H,1-2H3,(H,17,18);/q;+1/p-1
2D structure diagram/image available?
Yes
General status
Pesticide type
Herbicide
Substance groups
Pyrimidinyloxybenzoic acid herbicide
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Causes tissue death. Inhibits plant amino acid synthesis - acetohydroxyacid synthase AHAS.
CAS RN
123343-16-8
EC number
602-931-3
CIPAC number
-
US EPA chemical code
078905
PubChem CID
23682187
CLP index number
No data found
Molecular mass
348.74
PIN (Preferred Identification Name)
sodium 2-chloro-6-[(4,6-dimethoxypyrimidin-2-yl)sulfanyl]benzoate
IUPAC name
sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoate
CAS name
sodium 2-chloro-6-[(4,6-dimethoxy-2-pyrimidinyl)thio]benzoate
Other status information
-
Relevant Environmental Water Quality Standards
-
Herbicide Resistance Class (HRAC MoA class)
B
Herbicide Resistance Class (WSSA MoA class)
2
Insecticide Resistance Class (IRAC MoA class)
Not applicable
Fungicide Resistance Class (FRAC MOA class)
Not applicable
Examples of recorded resistance
Amaranthus palmeri
Physical state
Off-white powder
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • DuPont
  • Kumiai Chemical Industry Co. Ltd.
Example products using this active
  • Stap
  • Staple
  • Staple LX
Formulation and application details
Usually supplied as a soluble powder
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
728000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
High
Solubility - In organic solvents at 20 °C (mg l⁻¹)
812
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Acetone
-
270000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Methanol
-
10
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
n-Hexane
-
205
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Ethyl acetate
-
Melting point (°C)
234
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Boiling point (°C)
- - -
Degradation point (°C)
234
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
1.45 X 10-01 Calculated -
Log P
-0.84
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Low
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
1.61
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Dissociation constant pKa) at 25 °C
2.34
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Strong acid
Vapour pressure at 20 °C (mPa)
4.80 X 10-06
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
- - -
Volatilisation as max % of applied dose lost
From plant surface
- - -
From soil surface
- - -
Maximum UV-vis absorption L mol⁻¹ cm⁻¹
- - -
Surface tension (mN m⁻¹)
- - -
Degradation
Property
Value
Source; quality score; and other information
Interpretation
General biodegradability
-
Soil degradation (days) (aerobic)
DT₅₀ (typical)
60
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Moderately persistent
DT₅₀ (lab at 20 °C)
- - -
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
General literature data states DT₅₀ 60 days in silty soil. DT₅₀ 10 days for uplands and flooded soil. Main degradation route is microbial.
Dissipation rate RL₅₀ (days) on plant matrix
Value
- - -
Note
-
Dissipation rate RL₅₀ (days) on and in plant matrix
Value
- - -
Note
-
Aqueous photolysis DT₅₀ (days) at pH 7
Value
13
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Moderately fast
Note
pH sensitive: DT₅₀ 11 days at pH 5, 15 days at pH 9, all at 25 °C
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
Stable
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Stable
Note
-
Water-sediment DT₅₀ (days)
- - -
Water phase only DT₅₀ (days)
- - -
Sediment phase only DT₅₀ (days)
- - -
Air degradation
As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.
Decay in stored produce DT₅₀
-
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd (mL g⁻¹)
0.5
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
-
Koc (mL g⁻¹)
-
Notes and range
General literature data gives Kd values ranging from 0.32 (sandy loam) to 0.75 (silty loam). Peered review study - Kd 0.22 to 0.59 L/kg
Freundlich
Kf (mL g⁻¹)
- - -
Kfoc (mL g⁻¹)
-
1/n
-
Notes and range
-
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
- - -
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
Cannot be calculated - -
Note
-
Potential for particle bound transport index
- - -
Potential for loss via drain flow
- - -
Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk
- - -
Bio-concentration factor
BCF (l kg⁻¹)
Low risk
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
Based on LogP < 3
Low risk
CT₅₀ (days)
- -
Known metabolites

None

ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
3200
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
Low
Mammals - Short term dietary NOEL
(mg kg⁻¹)
- - -
(ppm diet)
- -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
> 1500
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Anas platyrhynchos
Moderate
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
- - -
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
- - -
Soil micro-organisms
- - -
Collembola
Acute LC₅₀ (mg kg⁻¹)
- - -
Chronic NOEC (mg kg⁻¹)
- - -
Non-target plants
- - -
- - -
Honeybees (Apis spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
> 25
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Moderate
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Chronic
- - -
Bumblebees (Bombus spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
-
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
-
Mason bees (Osmia spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Other bee species (1)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Other bee species (2)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Beneficial insects (Ladybirds)
- - -
Beneficial insects (Lacewings)
- - -
Beneficial insects (Parasitic wasps)
- - -
Beneficial insects (Predatory mites)
- - -
Beneficial insects (Ground beetles)
- - -
Aquatic ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
> 930
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Lepomis macrochirus
Low
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
> 1100
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Daphnia magna
Low
Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
260
P3 P = Other non-EU, UK or US Governments and Regulators
3 = Unverified data of known source
Daphnia magna
Low
Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
- - -
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)
> 140.0
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
Americamysis bahia
Low
Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)
- - -
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)
- - -
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)
0.0009
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Lemna gibba
High
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
95.0
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Selenastrum capricornutum
Low
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
Mesocosm study data
NOEAEC mg l⁻¹
- - -
NOEAEC mg l⁻¹
- - -
Marine bivalves
- - -
HUMAN HEALTH AND PROTECTION
General
Property
Value
Source; quality score; and other information
Interpretation
Threshold of Toxicological Concern (Cramer Class)
High (class III) - -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
3200
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
Low
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
2000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rabbit
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
6.9
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
-
Other Mammal toxicity endpoints
- - -
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
- - -
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
- - -
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)
- - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)
- - -
Dermal penetration studies (%)
- - -
Dangerous Substances Directive 76/464
- - -
Exposure Routes
Public
-
Occupational
-
MRLs
European
EU MRL pesticide database 
Great Britain
GB MRL Register 
Notes
-
Drinking Water Standards
- - -
Drinking Water MAC (μg l⁻¹)
- - -
Mammalian dose elimination route and rate
- - -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
?Possibly, status not identified
A0 A = Chromosome aberration (EFSA database)
0 = No data
;
B0 B = DNA damage/repair (EFSA database)
0 = No data
;
C0 C = Gene mutation (EFSA database)
0 = No data
;
D0 D = Genome mutation (EFSA database)
0 = No data
;
E3 E = Unspecified genotoxicity type (miscellaneous data source)
3 = Negative
No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
No data found
XNo, known not to cause a problem
No data found
Respiratory tract irritant Skin irritant Skin sensitiser
No data found
XNo, known not to cause a problem
No data found
Eye irritant Phototoxicant  
XNo, known not to cause a problem
No data found  
General human health issues
Moderately toxic
Possible liver toxicant
US EPA - possible human carcinogen; CLP data - suspected carcinogen
Handling issues
Property
Value and interpretation
General
No information available
CLP classification 2013
Health: H319, H351, H373
Environment: H400, H410
WHO Classification
III (Slightly hazardous)
UN Number
-
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
pyrithiobac-sodium
French
-
German
-
Danish
-
Italian
-
Spanish
piritiobac sodico
Greek
-
Polish
pirytiobak sodowy
Swedish
-
Hungarian
-
Dutch
-
Norwegian
-

Record last updated: 21/08/2024
Contact: aeru@herts.ac.uk
Please cite as: Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242