pyrithiobac-sodium (Ref: DPX PE 350)
** KIH 2031 ** Translations

Environmental Fate - Ecotoxicology - Human Health

SUMMARY

Pyrithiobac-sodium is a post-emergence herbicide without EU regulatory approval for use. It has a high aqueous solubility, is non-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.

GENERAL INFORMATION
for pyrithiobac-sodium

Description: Post-emergence control of broad-leaved weeds in cotton and other crops

Introduction: 1995, USA

EC Regulation 1107/2009 (repealing 91/414):
Status Not listed
Dossier rapporteur/co-rapporteur Not applicable
Date inclusion expires Not applicable

Approved for use () or known to be used () in the following European countries:

AT

BE

BG

CY

CZ

DE

DK

EE

EL

ES

FI

FR

HU

IE

IT

LT

LU

LV

MT

NL

PL

PT

RO

SE

SI

SK

UK

Also registered in: Australia

General status:
Pesticide type Herbicide
Substance group Pyrimidinyloxybenzoic analogue
Substance origin Synthetic
Mode of action Causes tissue death. Acetolactate synthase (ALS) inhibitor.
CAS RN 123343-16-8
EC number -
CIPAC number -
US EPA chemical code 078905
Chiral molecule No
Chemical formula C13H10ClN2NaO4S
SMILES [Na+].[O-]C(=O)c2c(Sc1nc(OC)cc(OC)n1)cccc2Cl
International Chemical Identifier (InChI) InChI=1/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
Structure diagram/image available? Yes
Molecular mass (g mol-1) 348.74
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 -
Herbicide Resistance Classification (HRAC) B
Insecticide Resistance Classification (IRAC) Not applicable
Fungicide Resistance Classification (FRAC) Not applicable
Physical state Off-white powder
Related substances & organisms -

Formulations:
Property Value
Example manufacturers of products using this active
  • DuPont
  • Kumiai Chemical Industry Co. Ltd.
Example products using this active
  • Stap
  • Staple
  • Staple LX
UK LERAP status No UK approval for use or outside scope
Formulation and application details Usually supplied as a soluble powder.


ENVIRONMENTAL FATE

for pyrithiobac-sodium

Property Value Source/Quality Score/Other Information Interpretation
Solubility - In water at 20oC (mg l-1) 728000 L3 High
Solubility - In organic solvents at 20oC (mg l-1) 812 L3 - Acetone -
270000 L3 - Methanol -
10 L3 - n-Hexane -
205 L3 - Ethyl acetate -
Melting point (oC) 234 L3 -
Boiling point (oC) - - -
Degradation point (oC) 234 L3 -
Flashpoint (oC) - - -
Octanol-water partition coefficient at pH 7, 20oC P 1.45 X 10-01 Calculated -
Log P -0.84 L3 Low
Bulk density (g ml-1)/Specific gravity 1.61 L3 -
Dissociation constant (pKa) at 25oC 2.34 L3 -
Note: Strong acid
Vapour pressure at 25oC (mPa) 4.80 X 10-06 L3 Non-volatile
Henry's law constant at 25oC (Pa m3 mol-1) - - -
Henry's law constant at 20oC (dimensionless) 9.44 X 10-16 Calculated Non-volatile
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 - - -
Note -
Potential for particle bound transport index - - -
Maximum UV-vis absorption L mol-1 cm-1 - - -
Surface tension (mN m-1) - - -

Degradation:
Property Value Source/Quality Score/Other Information Interpretation
Soil degradation (days) (aerobic) DT50 (typical) 60 L3 Moderately persistent
DT50 (lab at 20oC) - - -
DT50 (field) - - -
DT90 (lab at 20oC) - - -
DT90 (field) - - -
Note General literature data states DT50 60 days in silty soil. DT50 10 days for uplands and flooded soil. Main degradation route is microbial.
Aqueous photolysis DT50 (days) at pH 7 Value 13 L3 Moderately fast
Note pH sensitive: DT50 11 days at pH 5, 15 days at Ph 9, all at 25 degC
Aqueous hydrolysis DT50 (days) at 20oC and pH 7 Value Stable L3 Very persistent
Note -
Water-Sediment DT50 (days) - - -
Water phase only DT50 (days) - - -

Soil adsorption and mobility:
Property Value Source/Quality Score/Other Information Interpretation
Linear Kd 0.5 F3 -
Koc -
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 - - -
Kfoc -
1/n -
Notes and range -
pH sensitivity -


ECOTOXICOLOGY

for pyrithiobac-sodium

Property Value Source/Quality Score/Other Information Interpretation
Bio-concentration factor BCF Low risk Q3 Based on LogP < 3 High potential
CT50 (days) - -
Bioaccumulation potential - Calculated Low
Mammals - Acute oral LD50 (mg kg-1) 3200 L3 Rat Low
Mammals - Short term dietary NOEL (mg kg-1) - - -
(ppm diet) - -
Birds - Acute LD50 (mg kg-1) > 1500 F4 Anas platyrhynchos Moderate
Birds - Short term dietary (LC50/LD50) - - -
Fish - Acute 96 hour LC50 (mg l-1) > 930 F4 Lepomis macrochirus Low
Fish - Chronic 21 day NOEC (mg l-1) - - -
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) > 1100 L3 Daphnia magna Low
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) - - -
Aquatic crustaceans - Acute 96 hour LC50 (mg l-1) > 140.0 F3 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 Lemna gibba High
Algae - Acute 72 hour EC50, growth (mg l-1) 95.0 F4 Selenastrum capricornutum Low
Algae - Chronic 96 hour NOEC, growth (mg l-1) - - -
Honeybees - Acute 48 hour LD50 (μg bee-1) > 25 F4 Contact Moderate
Earthworms - Acute 14 day LC50 (mg kg-1) - - -
Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1) - - -
Other soil macro-organisms - e.g. Collembola LR50 / EC50 / NOEC / % Effect - - -
Other arthropod (1) LR50 g ha-1 - - -
% Effect - - -
Other arthropod (2) LR50 g ha-1 - - -
% Effect - - -
Soil micro-organisms - - -
Mesocosm study data NOEAEC mg l-1 - - -
NOEAEC mg l-1 - - -


HUMAN HEALTH AND PROTECTION

for pyrithiobac-sodium

General:
Property Value Source/Quality Score/Other Information Interpretation
Mammals - Acute oral LD50 (mg kg-1) 3200 L3 Rat Low
Mammals - Dermal LD50 (mg kg-1 body weight) > 2000 L3 Rabbit -
Mammals - Inhalation LC50 (mg l-1) 6.9 L3 Rat -
Other Mammal toxicity endpoints - -
ADI - Acceptable Daily Intake (mg kg-1bw day-1) - - -
ARfD - Acute Reference Dose (mg kg-1bw day-1) - - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) - - -
Dermal penetration studies (%) - - -
Dangerous Substances Directive 76/464 - - -
Exposure Limits - - -
Exposure Routes Public -
Occupational -
Examples of European MRLs (mg kg-1) Value -
Note For the EU pesticides database click here
Drinking Water MAC (μg l-1) - - -

Health issues:
Carcinogen Mutagen Endocrine disrupter Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant Respiratory tract irritant Skin irritant Eye irritant

-

-

-

-

General human health issues Moderately toxic
Possible liver toxicant

: Yes, known to cause a problem
: No, known not to cause a problem
: Possibly, status not identified
- : No data

Handling issues:
Property Value Source/Quality Score/Other Information Interpretation
General No information available
CLP classification 2013 -
EC Risk Classification Xn - Harmful: R22
EC Safety Classification -
WHO Classification III - Slightly hazardous
US EPA Classification (formulation) II - Warning - Moderately toxic
UN Number -
Waste disposal & packaging -


TRANSLATIONS

for pyrithiobac-sodium

Language Name
English pyrithiobac-sodium
French -
German -
Danish -
Italian -
Spanish piritiobac sodico
Greek -
Slovenian piritiobak-natrij
Polish pirytiobak sodowy
Swedish -
Hungarian -
Dutch -

Record last updated: Wednesday 12 March 2014
Contact: aeru@herts.ac.uk
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