(Also known as: protiophos; prothiophos; NTN 8629)
SUMMARY
Hazard 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. These hazard alerts do not take account of usage patterns or exposure, thus do not represent risk.
Environmental fate
Ecotoxicity
Human health
Environmental fate High alert: Potential for particle bound transport: High
Ecotoxicity High alert: Daphnia acute ecotoxicity: High
Human health High alert: Endocrine disrupter; Acetyl cholinesterase inhibitor; Neurotoxicant
GENERAL INFORMATION
Description
An insecticide used to control leaf eating insects
No UK approval for use as a plant protection agent
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)
-
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
Prothiofos exhibits stereoisomerism due to the presence of one chiral centre in its molecular structure. This chirality allows for the existence of two enantiomers. Although commercial formulations typically contain a racemic mixture of both enantiomers, each may differ in biological activity, toxicity, and environmental behaviour.
1976, first reported; 1978, first marketed; 2023, withdrawn New Zealand
Example manufacturers & suppliers of products using this active now or historically
Arysta LifeScience
Bayer
Example products using this active
Tokuthion Spray
Bideron
Formulation and application details
Usually formulated as an emulsifiable concentrate or wettable powder
Commercial production
The commercial production of prothiofos involves a multi-step chemical synthesis beginning with the chlorination of phenol to produce 2,4-dichlorophenol. This intermediate is then reacted with phosphorus pentasulfide or thiophosphoryl chloride and ethanol to form O,O-diethyl phosphorothioic chloride, a key activated precursor. In the final step, esterification occurs between the phosphorus intermediate and 2,4-dichlorophenol in the presence of a base such as pyridine, yielding prothiofos.
Impact on climate of production and use
Data for the amount of life cycle GHGs produced by prothiofos are not available in the public domain. However, whilst estimates vary, more general data suggests that between 14 and 19 kilograms of CO₂e is emitted per kilogram of insecticide produced.
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
0.07
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)
200000
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Toluene
-
200000
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Isopropanol
-
200000
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Dichloromethane
-
Melting point (°C)
-
-
-
Boiling point (°C)
-
-
-
Degradation point (°C)
-
-
-
Flashpoint (°C)
110
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
-
Octanol-water partition coefficient at pH 7, 20 °C
P
4.68 X 1005
Calculated
-
Log P
5.67
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)
1.31
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)
0.3
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)
3.05
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 3 = Unverified data of known source
Moderately volatile
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)
45
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)
45
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Moderately persistent
DT₉₀ (lab at 20 °C)
-
-
-
DT₉₀ (field)
-
-
-
DT₅₀ modelling endpoint
-
-
-
Note
Field studies DT₅₀ 1-2 months
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
0.5
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Fast
Note
-
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
pH sensitive: DT₅₀ 120 days at pH 4, 280 days at pH 7, 12 days at pH 9, all at 22 °C.
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)
-
Q2 Q = Miscellaneous data from online sources 2 = Unverified data of unknown source
Non-mobile
Koc (mL g⁻¹)
24158
Notes and range
Estimated
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
-0.63
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
High
Calculated
-
Potential for loss via drain flow
Non-mobile
Calculated
-
Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk
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
Environmental fate
