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Pyribenzoxim (Ref: LGC 40863 )
Last updated: 05/02/2024
(Also known as: pyanchor)

SUMMARY
Pyribenzoxim is a post-emergence herbicide. It has a low aqueous solubility and is volatile. Whilst data is sparse it indicates that the chemical is not persistent in soil systems. It has a low mammalian toxicity and is a recognised irritant. It is moderately toxic to birds, fish and honeybees.
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
Environmental fate
Moderate alert:
Potential for particle bound transport: Medium
Ecotoxicity
Low alert:
Fish acute ecotoxicity: Low; Daphnia acute ecotoxicity: Low; Bees acute unknown ecotoxicity: Low
Warning:
Significant data are missing
Human health
Low alert
Warning:
Significant data are missing
GENERAL INFORMATION
Description
Used post-emergence to control grasses and polygonums in rice and other crops
Example pests controlled
Barnyard grass; Blackgrass; Knotweed
Example applications
Rice; Wheat
Efficacy & activity
-
Availability status
-
Introduction & key dates
1997, registered Korea
UK regulatory status
UK COPR regulatory status
Not approved
Date COPR inclusion expires
Not applicable
UK LERAP status
No UK approval for use
EC Regulation 1107/2009 (repealing 91/414)
EC Regulation 1107/2009 status
Not approved
Dossier rapporteur/co-rapporteur
Not applicable
Date EC 1107/2009 inclusion expires
Not applicable
EU Candidate for substitution (CfS)
Not applicable
Listed in EU database
No
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
-
Chemical structure
Isomerism
None
Chemical formula
C₃₂H₂₇N₅O₈
Canonical SMILES
COC1=CC(=NC(=N1)OC2=C(C(=CC=C2)OC3=NC(=CC(=N3)OC)OC)C(=O)ON=C(C4=CC=CC=C4)C5=CC=CC=C5)OC
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
OVXMBIVWNJDDSM-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C32H27N5O8/c1-39-24-18-25(40-2)34-31(33-24)43-22-16-11-17-23(44-32-35-26(41-3)19-27(36-32)42-4)28(22)30(38)45-37-29(20-12-7-5-8-13-20)21-14-9-6-10-15-21/h5-19H,1-4H3
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
Broad spectrum and inhibits plant amino acid synthesis - acetohydroxyacid synthase AHAS.
CAS RN
168088-61-7
EC number
605-503-4
CIPAC number
None allocated
US EPA chemical code
-
PubChem CID
178117
CLP index number
No data found
Molecular mass
609.59
PIN (Preferred Identification Name)
N-({2,6-bis[(4,6-dimethoxypyrimidin-2-yl)oxy]benzoyl}oxy)-1,1-diphenylmethanimine
IUPAC name
benzophenone O-[2,6-bis(4,6-dimethoxypyrimidin-2-yloxy)benzoyl]oxime
CAS name
diphenylmethanone O-(2,6-bis((4,6-dimethoxy-2-pyrimidinyl)oxy)benzoyl)oxime
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
-
Physical state
White to pale yellow coloured solid
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • LG Chemicals, Korea
Example products using this active
  • Kiljabigold
  • Pyanchor
Formulation and application details
Usually supplied as an emulsifiable concentrate
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
3.5
R4 R = Peer reviewed scientific publications
4 = Verified data
Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)
- - -
Melting point (°C)
129
R4 R = Peer reviewed scientific publications
4 = Verified data
-
Boiling point (°C)
811
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
-
Degradation point (°C)
- - -
Flashpoint (°C)
444
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
-
Octanol-water partition coefficient at pH 7, 20 °C
P
1.10 X 1003 Calculated -
Log P
3.04
R4 R = Peer reviewed scientific publications
4 = Verified data
High
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
1.3
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
-
Dissociation constant pKa) at 25 °C
- - -
-
Vapour pressure at 20 °C (mPa)
0.99
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Low volatility. If applied directly to plants, drift is a concern & mitigation is advisable
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)
- - -
DT₅₀ (lab at 20 °C)
- - -
DT₅₀ (field)
7
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Non-persistent
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
-
Dissipation rate RL₅₀ (days) on plant matrix
Value
- - -
Note
-
Dissipation rate RL₅₀ (days) on and in plant matrix
Value
5.1
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
-
Note
Rice whole pant matrix, n=1
Aqueous photolysis DT₅₀ (days) at pH 7
Value
9.2
R4 R = Peer reviewed scientific publications
4 = Verified data
(distilled water)
Moderately fast
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
26.9
R4 R = Peer reviewed scientific publications
4 = Verified data
(de-aerated distilled water)
Non-persistent
Note
-
Water-sediment DT₅₀ (days)
- - -
Water 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)
- - -
Koc (mL g⁻¹)
-
Notes and range
-
Freundlich
Kf (mL g⁻¹)
9979
R4 R = Peer reviewed scientific publications
4 = Verified data
Non-mobile
Kfoc (mL g⁻¹)
534500
1/n
-
Notes and range
Literature data: Kf range 2100 (clay) - 20654 (silt loam) mL g⁻¹, Kfoc values range 85700 (clay) - 2470000 (silt loam) mL g⁻¹
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
-1.46 Calculated Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
5.35 X 10-03 Calculated -
Note
Estimated concentrations of chemicals with Koc values greater than 9995 ml g⁻¹ are beyond the scope of the regression data used in SCI-GROW development. If there are concerns for such chemicals, a higher tier groundwater exposure assessment should be considered, regardless of the concentration returned by SCI-GROW
Potential for particle bound transport index
Medium Calculated -
Potential for loss via drain flow
Non-mobile Calculated -
Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk
- - -
Bio-concentration factor
BCF (l kg⁻¹)
- - -
CT₅₀ (days)
- -
Known metabolites

None

ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 5000
R4 R = Peer reviewed scientific publications
4 = Verified data
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)
- - -
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)
- - -
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)
> 100
L2 L = Pesticide manuals and hard copy reference books / other sources
2 = Unverified data of unknown source
Low
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)
> 100
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
Orizias ¡atipes
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)
> 100
R4 R = Peer reviewed scientific publications
4 = Verified data
Daphnia magna
Low
Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
- - -
Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
- - -
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
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)
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
100
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
Unknown species
Low
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
Mesocosm study data
NOEAEC mg l⁻¹
- - -
NOEAEC mg l⁻¹
- - -
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)
> 5000
R4 R = Peer reviewed scientific publications
4 = Verified data
Rat
Low
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
2000
R4 R = Peer reviewed scientific publications
4 = Verified data
Rat
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
- - -
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
XNo, known not to cause a problem
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
;
E0 E = Unspecified genotoxicity type (miscellaneous data source)
0 = No data
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
Yes, known to cause a problem
Yes, known to cause a problem
No data found
Eye irritant Phototoxicant  
Yes, known to cause a problem
No data found  
General human health issues
Harmful via inhalation, ingestion and in contact with skin
Handling issues
Property
Value and interpretation
General
No information available
CLP classification 2013
Health: H332
WHO Classification
Not listed (Not listed)
UN Number
-
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
pyribenzoxim
French
-
German
-
Danish
-
Italian
-
Spanish
-
Greek
-
Polish
pirybenzoksym
Swedish
-
Hungarian
-
Dutch
-
Norwegian
-

Record last updated: 05/02/2024
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