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Parathion-ethyl (Ref: OMS 19)
Last updated: 25/02/2021
(Also known as: parathion; thiophos; ethyl parathion; BAY 9491; ENT 15108; AC 3422)

SUMMARY
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; Daphnia acute ecotoxicity: High; Daphnia chronic ecotoxicity: High; Bees acute oral ecotoxicity: High; Bees acute unknown ecotoxicity: High
Human health
High alert:
Mammals acute toxicity: High; Reproduction/development effects
GENERAL INFORMATION
Description
A broad-spectrum insecticide and acaricide used to control sucking and chewing insects and mites
Example pests controlled
Aphids; Mealybugs; Codling moth; Scale, Leafhoppers
Example applications
Alfalfa; Barley; Rapseed; Cotton; Sorghum; Soybeans; Sunflowers; Wheat; Broccoli; Brussel sprouts
Efficacy & activity
-
Availability status
Obsolete. Banned in many countries.
Introduction & key dates
circa 1950
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
Italy
Date EC 1107/2009 inclusion expires
Expired
EU Candidate for substitution (CfS)
Not applicable
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
                 
Also used in
Also used in
-
Chemical structure
Isomerism
None
Chemical formula
C₁₀H₁₄NO₅PS
Canonical SMILES
CCOP(=S)(OCC)OC1=CC=C(C=C1)[N+](=O)[O-]
Isomeric SMILES
No data
International Chemical Identifier key (InChIKey)
LCCNCVORNKJIRZ-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C10H14NO5PS/c1-3-14-17(18,15-4-2)16-10-7-5-9(6-8-10)11(12)13/h5-8H,3-4H2,1-2H3
2D structure diagram/image available?
Yes
General status
Pesticide type
Insecticide, Acaricide
Substance group
Organophosphate
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Non-systemic with contact, stomach and some respiratory action. Acetylcholinesterase (AChE) inhibitor.
CAS RN
56-38-2
EC number
200-271-7
CIPAC number
10
US EPA chemical code
057501
PubChem CID
991
Molecular mass
291.27
PIN (Preferred Identification Name)
O,O-diethyl-O-4-nitrophenyl phosphorothioate
IUPAC name
O,O-diethyl O-4-nitrophenyl phosphorothioate
CAS name
O,O-diethyl O-(4-nitrophenyl) phosphorothioate
Other status information
PIC Annex III; Potential groundwater contaminant; Marine Pollutant; Rotterdam Convention (Class Ia)
Relevant Environmental Water Quality Standards
-
Herbicide Resistance Classification (HRAC)
Not applicable
Herbicide Resistance Classification (WSSA)
Not applicable
Insecticide Resistance Classification (IRAC)
1B
Fungicide Resistance Classification (FRAC)
Not applicable
Examples of recorded resistance
Adoxophyes orana, Aedes dorsalis, Aedes melanimon, Aedes nigromaculis, Amblyseius potentillae, Bemisia tabaci, many others
Physical state
White crystalline solid with foul odour when pure. technical substance may be a pale yellow liquid
Related substances & organisms
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Folidol E
  • Niran
  • Woprophos
  • Fighter
  • Co-thion
  • Alkron
  • Vitrex
Example products using this active
  • Bayer Crop Protection
  • Monsanto
  • Cheminova
  • King Tech
  • Fujian Sannong Group Co. Ltd.
Formulation and application details
Available in a variety of formulations including dusts, emulsion concentrates, granules, ULV liquids and wettable powders
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
12.4
G4 G = Extension Toxicology network database EXTOXNET (click here )
4 = Verified data
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
Dichloromethane
-
200000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Toluene
-
75000
L2 L = Pesticide manuals and hard copy reference books / other sources
2 = Unverified data of unknown source
Hexane
-
200000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Isopropanol
-
Melting point (°C)
6.1
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Boiling point (°C)
375
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Degradation point (°C)
- - -
Flashpoint (°C)
174
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
6.76 X 1003 Calculated -
Log P
3.83
G4 G = Extension Toxicology network database EXTOXNET (click here )
4 = Verified data
High
Bulk density (g ml⁻¹)
1.26
AC4 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here )
4 = Verified data
-
Dissociation constant pKa) at 25 °C
- - -
-
Vapour pressure at 20 °C (mPa)
0.89
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)
3.02 X 10-02
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)
49
K4 K = Research datasets, e.g. Pandora, Demetra
4 = Verified data
Moderately persistent
DT₅₀ (lab at 20 °C)
14
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
Non-persistent
DT₅₀ (field)
17
AC4 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here )
4 = Verified data
Non-persistent
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
ICULID datasheet DT₅₀ lab studies 3-32 days, field studies DT₅₀ range 2-58 days; Other sources: 7DT₅₀ -10 days (R3)
Dissipation rate RL₅₀ on plant matrix
Value
3.8
R4 R = Peer reviewed scientific publications
4 = Verified data
-
Note
Published literature RL₅₀ range 0.2-19.6 days, wide range of field grown crops and wide range of matrics, n=30
Dissipation rate RL₅₀ on and in plant matrix
Value
5.1 - -
Note
Published literature RL₅₀ range 0.7-31.1 days, wide range of field grown crops and wide range of matrics, n=32
Aqueous photolysis DT₅₀ (days) at pH 7
Value
30
AC4 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here )
4 = Verified data
Stable
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
260
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Persistent
Note
pH sensitive: DT₅₀ 272 days at pH 4, 130 days at pH 9, all at 22 °C
Water-sediment DT₅₀ (days)
4.3
K4 K = Research datasets, e.g. Pandora, Demetra
4 = Verified data
Fast
Water phase only DT₅₀ (days)
3.5
K4 K = Research datasets, e.g. Pandora, Demetra
4 = Verified data
Moderately fast
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
-
H3 H = The US ARS pesticide properties database (click here )
3 = Unverified data of known source
Non-mobile
Koc
7660
Notes and range
Other sources: 316.2-15849 mL g⁻¹ (R3)
Freundlich
Kf
17
R4 R = Peer reviewed scientific publications
4 = Verified data
Slightly mobile
Kfoc
580
1/n
0.95
Notes and range
Kf range 13.0-21.0 (229 for peat) mL g⁻¹, Kfoc range 491-636 (355 for peat) mL g⁻¹, 1/n - no data, Soils=4
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
1.52 Calculated Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
3.32 X 10-02 Calculated -
Note
-
Potential for particle bound transport index
Medium Calculated -
Potential for loss via drain flow
Non-mobile Calculated -
ECOTOXICOLOGY
Property
Value
Source; quality score; and other information
Interpretation
Bio-concentration factor
BCF (l kg⁻¹)
40
P4 P = Other governments and regulators
4 = Verified data
(Other literature values Log BCF range 1.1-1.9 (R3))
Low potential
CT₅₀ (days)
<0.5 -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
2
G4 G = Extension Toxicology network database EXTOXNET (click here )
4 = Verified data
Rat
High
Mammals - Short term dietary NOEL
(mg kg⁻¹)
-
L2 L = Pesticide manuals and hard copy reference books / other sources
2 = Unverified data of unknown source
Rat 2 year
-
(ppm diet)
2 -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
2.1
G4 G = Extension Toxicology network database EXTOXNET (click here )
4 = Verified data
Anas platyrhynchos
High
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
1.5
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Oncorhynchus mykiss
Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)
> 0.098
P3 P = Other governments and regulators
3 = Unverified data of known source
Danio rerio
Moderate
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
0.0025
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Daphnia magna
High
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
0.0001
P3 P = Other governments and regulators
3 = Unverified data of known source
Daphnia magna
High
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)
0.00011
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Americamysis bahia
High
Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)
0.14
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
Chironomus riparius 1 day
Moderate
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)
- - -
Non-target plants
- - -
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
10.0
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Scenedemus subspicatus
Moderate
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
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)
> 0.21
R4 R = Peer reviewed scientific publications
4 = Verified data
High
Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
> 0.175
F2 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
2 = Unverified data of unknown source
Apis mellifera
High
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 pollinators (1)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Other pollinators (2)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
> 267
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Eisenia foetida
Moderate
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
- - -
Other soil macro-organisms
Acute LC₅₀ (mg kg⁻¹)
- - -
Chronic NOEC (mg kg⁻¹)
- - -
Other arthropod (1)
LR₅₀ g ha⁻¹
- - -
% Effect
Harmful
AB1 AB = SELECTV Database
1 = Estimated data with little or no verification
Typhlodromus pyri
-
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
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)
2
G4 G = Extension Toxicology network database EXTOXNET (click here )
4 = Verified data
Rat
High
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
71.0
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
0.03
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat (aerosol)
-
Other Mammal toxicity endpoints
- - -
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
0.0006
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
-
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
0.005
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
-
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 
Notes
-
Drinking Water Standards
EU Drinking Water standards: A1 waters: 0.001 mg l⁻¹, A2 waters 0.0025 mg l⁻¹, A3 waters: 0.005 mg l⁻¹
EU Directive for the protection of shelfish intended for human consumption: 100 µg l⁻¹
B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
5 = Verified data used for regulatory purposes
UK EA QS database 2018
-
Drinking Water MAC (μg l⁻¹)
- - -
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
;
E1 E = Unspecified genotoxicity type (miscellaneous data source)
1 = Positive
?Possibly, status not identified
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
Yes, known to cause a problem
No data found
XNo, known not to cause a problem
Respiratory tract irritant Skin irritant Skin sensitiser
Yes, known to cause a problem
Yes, known to cause a problem
XNo, known not to cause a problem
Eye irritant Phototoxicant  
Yes, known to cause a problem
No data found  
General human health issues
Highly toxic
Possible brain toxicant
USEPA - possible human carcinogen
Handling issues
Property
Value and interpretation
General
IMDG Transport Code is usually 6.1
CLP classification 2013
Health: H300, H311, H330, H372
Environment: H400, H410
EC Risk Classification
T+ - Very toxic: R26/28
T - Toxic: R24, R48/25
N - Dangerous for the environment: R50, R53
EC Safety Classification
S1/2, S28, S36/37, S45, S60, S61
WHO Classification
Ia (Extremely hazardous)
UN Number
3018
Waste disposal & packaging
Packaging Group I (great danger)
TRANSLATIONS
Language
Name
English
parathion-ethyl
French
parathion
German
Parathion
Danish
parathion
Italian
paration
Spanish
paratión
Greek
parathion
Polish
paration
Swedish
-
Hungarian
-
Dutch
parathion

Record last updated: 25/02/2021
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