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Parathion-methyl (Ref: OMS 213)
Last updated: 27/11/2019
(Also known as: metaphos; meptox; thiophenit; quinophos; methyl-parathion)

GENERAL INFORMATION
Description
An insecticide used to control sucking and chewing insects in a wide range of crops
Example pests controlled
Aphids; Boll weevils; Mealybugs; Scale; Armyworms
Example applications
Cereals; Cotton; Vegetables; Soybean; Fruit; Vines
Efficacy & activity
-
Availability status
Current
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)
-
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
Australia, USA, Costa Rica
Chemical structure
Isomerism
-
Chemical formula
C₈H₁₀NO₅PS
Canonical SMILES
COP(=S)(OC)OC1=CC=C(C=C1)[N+](=O)[O-]
Isomeric SMILES
No data
International Chemical Identifier key (InChIKey)
RLBIQVVOMOPOHC-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C8H10NO5PS/c1-12-15(16,13-2)14-8-5-3-7(4-6-8)9(10)11/h3-6H,1-2H3
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
parathion-methyl -
General status
Pesticide type
Insecticide
Substance group
Organophosphate
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Contact and stomach insecticide. Cholinesterase inhibitor.
CAS RN
298-00-0
EC number
206-050-1
CIPAC number
487
US EPA chemical code
053501
PubChem CID
4130
Molecular mass
263.21
PIN (Preferred Identification Name)
-
IUPAC name
O,O-dimethyl O-4-nitrophenyl phosphorothioate
CAS name
O,O-dimethyl O-(4-nitrophenyl) phosphorothioate
Other status information
Chemical subject to PIC regulations; Potential groundwater contaminant; Marine Pollutant
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
Aedes melanimon, Aedes nigromaculis, Anopheles albimanus, Coleomegilla maculata, Culex pipiens pallens, many others
Physical state
Colourless crystals
Related substances & organisms
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Sweeper
  • Amithion
  • Prompt
  • Sabidol
  • Wolfatox
Example products using this active
  • Bayer CropScience
  • FCC Ltd
  • Cheminova A/S
  • Monsanto
Formulation and application details
Available in a wide variety of formulations including dustable powders, emulsifible concentrates, encapsulated suspensions, ULV liquid and wettable powders.
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
55
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)
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
-
15000
L2 L = Pesticide manuals and hard copy reference books / other sources
2 = Unverified data of unknown source
Hexane
-
Melting point (°C)
35.5
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Boiling point (°C)
- - -
Degradation point (°C)
- - -
Flashpoint (°C)
150
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
1.00 X 1003 Calculated -
Log P
3
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Moderate
Bulk density (g ml⁻¹)
1.36
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)
0.2
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)
8.57 X 10-03
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)
12
Y4 Y = Germany's Federal Environment Agency (UBA) (click here )
4 = Verified data
Non-persistent
DT₅₀ (lab at 20 °C)
12
Y4 Y = Germany's Federal Environment Agency (UBA) (click here )
4 = Verified data
Non-persistent
DT₅₀ (field)
10
Y4 Y = Germany's Federal Environment Agency (UBA) (click here )
4 = Verified data
Non-persistent
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
PIC DGD states lab DT₅₀ range 1-18 days
Dissipation rate RL₅₀ on plant matrix
Value
3.6
R4 R = Peer reviewed scientific publications
4 = Verified data
-
Note
Published literature RL₅₀ range 0.4-6.7 days, 6 field crops, various matrices, n=8
Dissipation rate RL₅₀ on and in plant matrix
Value
1.9
R4 R = Peer reviewed scientific publications
4 = Verified data
-
Note
Published literature RL₅₀ range 0.7-6.6 days, 7 field crops, various matrices, n=12; Fruit in cold storage RL₅₀ range 63-65 days, n=2
Aqueous photolysis DT₅₀ (days) at pH 7
Value
9
Q2 Q = Miscellaneous internet resources
2 = Unverified data of unknown source
Moderately fast
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
21
K4 K = Research datasets, e.g. Pandora, Demetra
4 = Verified data
Non-persistent
Note
-
Water-sediment DT₅₀ (days)
5
Q2 Q = Miscellaneous internet resources
2 = Unverified data of unknown source
Fast
Water phase only DT₅₀ (days)
15
Q2 Q = Miscellaneous internet resources
2 = Unverified data of unknown source
Slow
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
3 = Unverified data of known source
Moderately mobile
Koc
240
Notes and range
-
Freundlich
Kf
34.4
R4 R = Peer reviewed scientific publications
4 = Verified data
Moderately mobile
Kfoc
442
1/n
1.038
Notes and range
Literature data: Kf range 8.0-37.8 (178 for peat) mL g⁻¹, Kfoc range 276-677 (276 for peat) mL g⁻¹, 1/n range 0.909-1.123, Soils=8
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
1.35 Calculated Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
1.93 X 10-02 Calculated -
Note
-
Potential for particle bound transport index
Low Calculated -
Potential for loss via drain flow
Moderately mobile Calculated -
ECOTOXICOLOGY
Property
Value
Source; quality score; and other information
Interpretation
Bio-concentration factor
BCF (l kg⁻¹)
71
J3 J = Pesticide Action Network database (click here )
3 = Unverified data of known source
Oncorhynchus mykiss
Low potential
CT₅₀ (days)
Not available -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
3
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
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)
> 1044
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Anas platyrhynchos
Moderate
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
> 2.7
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)
0.0089
P3 P = Other governments and regulators
3 = Unverified data of known source
Cyprinodon variegatus
High
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
> 0.0073
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)
0.00018
P3 P = Other governments and regulators
3 = Unverified data of known source
Daphnia magna
High
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)
0.00035
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
Americamysis bahia
High
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)
- - -
Non-target plants
- - -
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
3
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
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)
19.5
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
Moderate
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)
- - -
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)
0.0157
R4 R = Peer reviewed scientific publications
4 = Verified data
Megachile rotundata
High
Mode of exposure
Contact
Other pollinators (2)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
0.096
R4 R = Peer reviewed scientific publications
4 = Verified data
Trigona spinipes
High
Mode of exposure
Contact
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
40
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
- - -
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)
3
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
High
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
45.0
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
0.17
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
-
Other Mammal toxicity endpoints
- - -
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
0.003
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
JMPR 1995
-
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
0.03
B4 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
4 = Verified data
UK ACP 1999
-
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
Skin absorption, and to a lesser extent inhalation and ingestion
European MRLs
EU MRL pesticide database 
Drinking Water Standards
- - -
Drinking Water MAC (μg l⁻¹)
- - -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
?Possibly, status not identified
A3 A = Chromosome aberration (EFSA database)
3 = Negative
;
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
?Possibly, status not identified
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
?Possibly, status not identified
Yes, known to cause a problem
Yes, known to cause a problem
Respiratory tract irritant Skin irritant Skin sensitiser
No data found No data found No data found
Eye irritant Phototoxicant  
No data found No data found  
General human health issues
Extremely hazardous
IARC Group 3 carcinogen; USEPA - not likely to be a human carcinogen
Handling issues
Property
Value and interpretation
General
Explosive on heating
Flammable
IMDG Transport Code is 6.1
CLP classification 2013
Handling: H226
Health: H300, H311, H330, H373
Environment: H400, H410
EC Risk Classification
T+ - Very toxic: R26/28
T - Toxic: R24
Xn - Harmful: R48/22
H - Handling risks: R5, R10
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
Active 2783, liquid products 3018
Waste disposal & packaging
-
TRANSLATIONS
Language
Name
English
parathion-methyl
French
parathion-methyl
German
Parathion-methyl
Danish
parathion-methyl
Italian
paration-metile
Spanish
paratión-metil
Greek
parathion-methyl
Polish
paration metylu
Swedish
-
Hungarian
-
Dutch
parathion-methyl

Record last updated: 27/11/2019
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