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Pyridafenthion (Ref: ENT 23968))
Last updated: 23/02/2024
(Also known as: piridafention; pyridiphenthion; CL 12503; NC 250; pyridiphenthion)

SUMMARY
Pyridafenthion is an organophosphate insecticide. It its moderately soluble in aqueous solution, is relatively volatile and is not persistent in soil. However, under certain conditions it may persist for a month or two in surface water. It is moderately toxic to mammals, is an acetyl cholinesterase inhibitor and a neurotoxicant. It is highly toxic to honeybees, earthworms and birds. data for aquatic organisms is limited but it is known to be moderately toxic to fish and algae.
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
High alert:
Birds acute ecotoxicity: High; Bees acute unknown ecotoxicity: High; Earthworms acute ecotoxicity: High
Human health
High alert:
Acetyl cholinesterase inhibitor; Neurotoxicant
GENERAL INFORMATION
Description
An organophosphate insecticide used to control sucking and chewing insects
Example pests controlled
Aphids; Thrips; Leafhoppers; Sawflies
Example applications
Rice; Vegetables; Fruit
Efficacy & activity
-
Availability status
-
Introduction & key dates
1973, first introduced Japan
UK regulatory status
UK COPR regulatory status
Not approved
Date COPR inclusion expires
Expired
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
Expired
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
C₁₄H₁₇N₂O₄PS
Canonical SMILES
CCOP(=S)(OCC)OC1=NN(C(=O)C=C1)C2=CC=CC=C2
Isomeric SMILES
No data
International Chemical Identifier key (InChIKey)
CXJSOEPQXUCJSA-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C14H17N2O4PS/c1-3-18-21(22,19-4-2)20-13-10-11-14(17)16(15-13)12-8-6-5-7-9-12/h5-11H,3-4H2,1-2H3
2D structure diagram/image available?
Yes
General status
Pesticide type
Insecticide
Substance groups
Organophosphate insecticide; Organothiophosphate insecticide
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Systemic, with stomach and contact action. Acetylcholinesterase (AChE) inhibitor.
CAS RN
119-12-0
EC number
204-298-5
CIPAC number
None allocated
US EPA chemical code
-
PubChem CID
8381
CLP index number
No data found
Molecular mass
340.33
PIN (Preferred Identification Name)
O-(1,6-dihydro-6-oxo-1-phenyl-3-pyridazinyl) O,O-diethyl phosphorothioate
IUPAC name
O-(1,6-dihydro-6-oxo-1-phenylpyridazin-3-yl) O,O-diethyl phosphorothioate
CAS name
O-(1,6-dihydro-6-oxo-1-phenyl-3-pyridazinyl) O,O-diethyl phosphorothioate
Other status information
PAN listed Highly Hazardous Chemical
Relevant Environmental Water Quality Standards
-
Herbicide Resistance Class (HRAC MoA class)
Not applicable
Herbicide Resistance Class (WSSA MoA class)
Not applicable
Insecticide Resistance Class (IRAC MoA class)
1B
Fungicide Resistance Class (FRAC MOA class)
Not applicable
Examples of recorded resistance
-
Physical state
Pale yellow solid
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Mitsui Chemicals
  • Sipcan
Example products using this active
  • Ofunack
  • Oreste
Formulation and application details
-
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
100
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Moderate
Solubility - In organic solvents at 20 °C (mg l⁻¹)
3880
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Hexane
-
812000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Toluene
-
930000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Acetone
-
785000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Ethyl acetate
-
Melting point (°C)
56.2
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Boiling point (°C)
Decomposes before boiling
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Degradation point (°C)
180
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
1.58 X 1003 Calculated -
Log P
3.2
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
High
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
1.325
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Dissociation constant pKa) at 25 °C
- - -
-
Vapour pressure at 20 °C (mPa)
0.00147
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)
5.00 X 10-06
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Non-volatile
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)
18
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Non-persistent
DT₅₀ (lab at 20 °C)
18
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Non-persistent
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
General literature states DT₅₀ 11-24 days
Dissipation rate RL₅₀ on plant matrix
Value
- - -
Note
-
Dissipation rate RL₅₀ on and in plant matrix
Value
9.5
R4 R = Peer reviewed scientific publications
4 = Verified data
-
Note
Published literature RL₅₀ range 4.5-17.6 days, rice field crop, various matrices, n=3
Aqueous photolysis DT₅₀ (days) at pH 7
Value
7
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Moderately fast
Note
DT₅₀ 19 days in sterile water, 7 days in natural water
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
46
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Moderately persistent
Note
pH sensitive: DT₅₀ 72 days at pH 5, 27 days at pH 9, all at 25 °C
Water-sediment DT₅₀ (days)
- - -
Water phase only DT₅₀ (days)
- - -
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
-
W3 W = French database provided by ARVALIS-Institut du Végétal. Dataset no longer available.
3 = Unverified data of known source
Non-mobile
Koc
7211
Notes and range
-
Freundlich
Kf
- - -
Kfoc
-
1/n
-
Notes and range
-
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
0.18 Calculated Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
6.39 X 10-03 Calculated -
Note
-
Potential for particle bound transport index
Medium Calculated -
Potential for loss via drain flow
Non-mobile Calculated -
Bio-concentration factor
BCF (l kg⁻¹)
1.4
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
Low potential
CT₅₀ (days)
Not available -
Known metabolites

None

ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
769
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
Moderate
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)
68
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Coturnix japonica
High
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
> 2.87
R4 R = Peer reviewed scientific publications
4 = Verified data
Eisenia foetida
High
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)
0.08
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Apis mellifera
High
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)
7.5
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
Oncorhynchus mykiss
Moderate
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)
- - -
Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
- - -
Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
1.0
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
Ceriodaphnia dubia
Moderate
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)
8.53
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Pseudokirchneriella subcapitata 48 hr
Moderate
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)
769
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
2100
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
> 1.13
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat 4 hr
-
Other Mammal toxicity endpoints
Intraperitoneal LD₅₀ = 64 mg kg⁻¹
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Mouse
-
Subcutaneous LD₅₀ = 305 mg kg⁻¹
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Rat
-
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
List I; List II - -
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
;
E3 E = Unspecified genotoxicity type (miscellaneous data source)
3 = Negative
XNo, known not to cause a problem
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
No data found
Yes, known to cause a problem
Yes, known to cause a problem
Respiratory tract irritant Skin irritant Skin sensitiser
Yes, known to cause a problem
XNo, known not to cause a problem
No data found
Eye irritant Phototoxicant  
?Possibly, status not identified
No data found  
General human health issues
Harmful if swallowed or inhalled
Handling issues
Property
Value and interpretation
General
IMDG Transport Hazard Class 6.1
CLP classification 2013
Handling: H224
Health: H319, H336
WHO Classification
II (Moderately hazardous)
UN Number
UN2783
Waste disposal & packaging
Packaging Group II (moderate danger)
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
pyridafenthion
French
pyridafenthion
German
Pyridafenthion
Danish
pyridafenthion
Italian
piridafention
Spanish
piridafention
Greek
-
Polish
pyridafention
Swedish
-
Hungarian
piridafentoin
Dutch
-
Norwegian
-

Record last updated: 23/02/2024
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