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methomyl (Ref: OMS 1196)
** DPX X1179 ** Translations

Environmental Fate - Ecotoxicology - Human Health - A to Z Index - Home

SUMMARY

Methomyl is an oxime carbamate insecticide currently approved for use in the EU. It is highly soluble in water but has a low volatility and would not normally be expected to leach to groundwater. It is not normally persistent in soil or water systems. It is highly toxic to mammals and a cholinesterase inhibitor. It shows a moderate to high toxicity to most fauna and flora.

GENERAL INFORMATION Click here for an explantaion of the general chemical status information
for methomyl

Description: An insecticide used to control a wide range of foliar and soil-borne insects. Also a pesticide transformation product

Example pests controlled: Lepidoptera, Coleoptera and Diptera

Example applications: Lettuce; Artichokes; Rhubarb; Orchard crops; Sod turf; Alfalfa; Sugarbeet; Cotton

Efficacy & activity: -

Availability status: Current

Introduction & key dates: First registered in the United States in 1968

EC Regulation 1107/2009 (repealing 91/414):
Status Approved
Dossier rapporteur/co-rapporteur Belgium/Romania
Date inclusion expires 31/08/2019
EU Candidate for substitution (CfS) Yes - low ADI / ARfD / AOEL
Listed in EU database Yes

Approved for use () or known to be used () in the following European countries: Click to access a note on the approvals information on this site

AT

BE

BG

CY

CZ

DE

DK

EE

EL

ES

FI

FR

HR

HU

IE

IT

LT

LU

LV

MT

NL

PL

PT

RO

SE

SI

SK

UK

Also used in: Australia, USA

Chemical structure: Click here for further information on the general chemical status information used on this site
Isomerism Isomeric - cis-isomer is strongly favored thermodynamically
Chemical formula C5H10N2O2S
Canonical SMILES CC(=NOC(=O)NC)SC
Isomeric SMILES C/C(=N\OC(=O)NC)/SC
International Chemical Identifier key (InChIKey) UHXUZOCRWCRNSJ-UHFFFAOYSA-N
International Chemical Identifier (InChI) InChI=1S/C5H10N2O2S/c1-4(10-3)7-9-5(8)6-2/h1-3H3,(H,6,8)/b7-4+
Structure diagram/image available? Yes

General status: Click here for further information on the general chemical status information used on this site
Pesticide type Insecticide, Acaricide, Metabolite
Metabolite Type Soil, Animal, Water, Plant
Substance group Carbamate
Minimum active substance purity 980 g/kg
Known relevant impurities EU dossier - None declared
Substance origin Synthetic
Mode of action Systemic with contact and stomach action. Cholinesterase inhibitor.
CAS RN 16752-77-5
EC number 240-815-0
CIPAC number 264
US EPA chemical code 090301
PubChem CID 5353758
Molecular mass (g mol-1) 162.21
PIN (Preferred Identification Name) -
IUPAC name S-methyl (EZ)-N-(methylcarbamoyloxy)thioacetimidate
CAS name methyl N-(((methylamino)carbonyl)oxy)ethanimidothioate
Other status information Marine Pollutant; Chemical subject to PIC regulations
Relevant Environmental Water Quality Standards -
Herbicide Resistance Classification (HRAC) Not applicable
Herbicide Resistance Classification (WSSA) Not applicable
Insecticide Resistance Classification (IRAC) 1A
Fungicide Resistance Classification (FRAC) Not applicable
Examples of recorded resistance Aphis gossypii
Bemisia tabaci
Chrysoperla carnea
Earias vittella
Frankliniella occidentalis
Heliothis assulta
many more
Physical state White crystalline solid
Related substances & organisms -

Can be a metabolite of:
Parent Formation medium Estimated maximum occurrence fraction 1107/2009 relevancy Click here for further information on 1107/2009 relevancy
thiodicarb Soil   0.800   Major fraction, Relevant
alanycarb Soil     -

Formulations:
Property Click here for information on the general product and branding information used on this site Value
Example manufacturers & suppliers of products using this active now or historically
  • AgroCare
  • Bayer CropScience
  • FCC
Example products using this active
  • Methomyl 20SC
  • Lannate
  • Lanox
  • Nudrin
  • Metofan
UK LERAP status No UK approval for use as a pesticide under EC Regulation 1107/2009
Formulation and application details Often supplied as a soluble concentrate or emulsifiable concentrate. May be applied aerially in the US.


ENVIRONMENTAL FATE

for methomyl

Property Click here for information on the parameters used to describe environmental fate on this site Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with fate data Interpretation Click here for information on the way in which we interpret environmental fate data
Solubility - In water at 20oC (mg l-1) 55000 A5 High
Solubility - In organic solvents at 20oC (mg l-1) 97100 A5 - n-Heptane -
250000 A5 - Acetone -
1000000 L3 - Methanol -
420000 L3 - Ethanol -
Melting point (oC) 79.6 A5 -
Boiling point (oC) Decomposes before boiling A5 -
Degradation point (oC) 192 A5 -
Flashpoint (oC) Not expected to self ignite; Not highly flammable A5 -
Octanol-water partition coefficient at pH 7, 20oC P 1.23 X 1000 Calculated -
Log P 0.09 A5 Low
Bulk density (g ml-1)/Specific gravity 1.32 A5 -
Dissociation constant (pKa) at 25oC Not applicable A5 - -
Note: No dissociation
Vapour pressure at 20oC (mPa) 0.72 A5 Low volatility
Henry's law constant at 25oC (Pa m3 mol-1) 2.13 X 10-06 A5 Non-volatile
GUS leaching potential index Click here for a note on the limitations of the GUS index 2.19 Calculated Transition state
SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate Click here for a note on the limitations of the SCI-GROW index Value 1.45 X 10-02 Calculated -
Note -
Potential for particle bound transport index Click here for a note on the limitations of the potential for particle bound transport index - Calculated Low
Maximum UV-vis absorption L mol-1 cm-1 Neutral solution: 234nm = 9010; [Acidic solution: 234nm = 8980; [Basic solution: 234nm = 8890 A5 -
Surface tension (mN m-1) 73.7 A5 at 20.1oC -

Degradation:
Property Click here for information on the parameters used to describe substance degradation Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with degradation data Interpretation Click here for information on the way in which we interpret substance degradation data
General biodegradability -
Soil degradation (days) (aerobic) DT50 (typical) 7 A5 Non-persistent
DT50 (lab at 20oC) 6.97 A5 Non-persistent
DT50 (field) - - -
DT90 (lab at 20oC) 25.3 A5 -
DT90 (field) - - -
DT50 modelling endpoint - - -
Note EU dossier lab studies DT50 range 4.6-8.6 days, DT90 range 15.4-38.2 days; Other sources: DT50 30 days (DW4)
Dissipation rate RL50 on plant matrix Value 3.0 R4 -
Note Published literature RL50 range 0.5-8.7 days, 8 field & undercover grown crops, various matrices, n=14
Dissipation rate RL50 on and in plant matrix Value 4.0 R4 -
Note Published literature RL50 range 0.9-6.4 days, 13 field & undercover grown crops, various matrices, n=14
Aqueous photolysis DT50 (days) at pH 7 Value Stable A5 -
Note -
Aqueous hydrolysis DT50 (days) at 20oC and pH 7 Value Stable A5 -
Note Stable pH 5 to pH 7, DT50 36 days at pH 9, all at 25 deg C
Water-sediment DT50 (days) 3.7 A5 Fast
Water phase only DT50 (days) 2.9 A5 Moderately fast

Soil adsorption and mobility:
Property Click here for information on the parameters used to describe substance adsorption and mobility Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with adsorption and mobility data Interpretation Click here for information on the way in which we interpret substance adsorption and mobility
Linear Kd - DW3 Mobile
Koc 72
Notes and range -
Freundlich Kf 0.381 A5 Mobile
Kfoc 25.2
1/n 0.86
Notes and range EU dossier Kf range 0.145-0.809 mL/g, Kfoc range 13.3-42.8 mL/g, 1/n range 0.82-0.89, Soils=5
pH sensitivity No

Key metabolites:
Metabolite Formation medium Estimated maximum occurrence fraction 1107/2009 relevancy Click here for further information on 1107/2009 relevancy
methomyl oxime (Ref: IN-X1177) Soil   0.022   Minor fraction, Not relevant

Other known metabolites:
Metabolite name and reference Aliases Formation medium / Rate Estimated maximum occurrence fraction Metabolising enzymes
acetonitrile - Water/sediment; Soil; Rat (Blood, Liver) - -
acetamide - Animal; Rat - -
N-acetyl-S-[1-[[[(methylamino)carbonyl]oxy]imino]ethyl]-L-cysteine methomyl mercapturate Rat (Urinary) - -
E-methyl N-[[(methylamino)carbonyl]oxy]ethanimidothioate
(Ref: IN-B1884)
anti-methomyl Animal - -
methyl-N-[[[(hydroxymethyl)amino]carbonyl]oxy]ethanimidothioate
(Ref: IN-G6520)
hydroxy methyl methomyl Plant - -
9-hydroxy-6-methyl-3-oxo-4-oxa-7-thia-2,5-diazadec-5-en-10-oic acid
(Ref: IN-HUZ57)
hydroxy cysteine of methomyl Plant - -
2-methyl-4-thiazolemethanol
(Ref: IN-NR282)
- Plant - -


ECOTOXICOLOGY

for methomyl

Property Click here for information on the parameters used to describe substance ecotoxicology Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with ecotoxicology data Interpretation Click here for information on the way in which we interpret substance ecotoxicology
Bio-concentration factor BCF (l kg-1) Low risk A5 Based on LogP < 3 Low potential
CT50 (days) - -
Mammals - Acute oral LD50 (mg kg-1) 30 A5 Rat High
Mammals - Short term dietary NOEL (mg kg-1) 6 A5 Rabbit High
(ppm diet) - -
Birds - Acute LD50 (mg kg-1) 24.2 A5 Colinus virginianus High
Birds - Short term dietary (LC50/LD50) > 518.8 mg kg bw-1 day-1 A5 Colinus virginianus -
Fish - Acute 96 hour LC50 (mg l-1) 0.63 A5 Lepomis macrochirus Moderate
Fish - Chronic 21 day NOEC (mg l-1) 0.076 A5 Moderate
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) 0.0076 J4 Daphnia magna High
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) 0.0016 A5 Daphnia magna High
Aquatic crustaceans - Acute 96 hour LC50 (mg l-1) 0.036 F3 Americamysis bahia High
Sediment dwelling organisms - Acute 96 hour LC50 (mg l-1) 0.032 A5 Chironomus riparius High
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) > 100 A5 Selenastrum capricornutum Low
Algae - Chronic 96 hour NOEC, growth (mg l-1) - - -
Honeybees Contact acute 48 hour LD50 (μg bee-1) 0.16 A5 High
Oral acute 48 hour LD50 (μg bee-1) 0.28 A5 High
Unknown mode acute 48 hour LD50 (μg bee-1) - - -
Earthworms - Acute 14 day LC50 (mg kg-1) 19 A5 Eisenia foetida Moderate
Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1) 1.5 A5 Eisenia foetida Moderate
Other soil macro-organisms - e.g. Collembola LR50 / EC50 / NOEC / % Effect - - -
Other arthropod (1) LR50 g ha-1 0.20 48 hour
A5 Aphidius rhopalosiphi, adult
-
% Effect - - -
Other arthropod (2) LR50 g ha-1 9.1 7 day
A5 Typhlodromus pyri, protonymph
-
% Effect - - -
Soil micro-organisms Nitrogen mineralisation: No significant adverse effect
Carbon mineralisation: No significant adverse effect
A5
Dose: 4.5 kg ha-1, 28 days
-
Mesocosm study data NOEAEC mg l-1 - - -
NOEAEC mg l-1 - - -


HUMAN HEALTH AND PROTECTION

for methomyl

General:
Property Click here for information on the parameters used to describe human health and protection issues Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with human health and protection data Interpretation Click here for information on the way in which we interpret human health and protection data
Threshold of Toxicological Concern (Cramer Class) Click here for a note on the limitations of the Cramer class High (class III) - -
Mammals - Acute oral LD50 (mg kg-1) 30 A5 Rat High
Mammals - Dermal LD50 (mg kg-1 body weight) > 2000 A5 Rat -
Mammals - Inhalation LC50 (mg l-1) 0.215 A5 Rat -
Other Mammal toxicity endpoints - -
ADI - Acceptable Daily Intake (mg kg-1bw day-1) 0.0025 A5 Rat, SF=100 -
ARfD - Acute Reference Dose (mg kg-1bw day-1) 0.0025 A5 Rat, SF=100 -
AAOEL - Acute Acceptable Operator Exposure Level (mg kg-1 bw day-1) - - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) 0.0025 A3 Rat, SF=100 -
Dermal penetration studies (%) 1.2-15.0 A5 concentration dependent -
Dangerous Substances Directive 76/464 - - -
Exposure Limits - - -
Exposure Routes Public No unacceptable risks to bystanders identified
Occupational Risk of expsoure via dermal absortption
Risk of exposure acceptable under label recommendations for use for personal protection clothing and equipment
European MRLs Click here for the EU MRL pesticide database
Drinking Water Standards - - -
Drinking Water MAC (μg l-1) - - -

Health issues:
Carcinogen Mutagen Endocrine disrupter Reproduction / development effects Cholinesterase inhibitor Neurotoxicant

-

Respiratory tract irritant Skin irritant Skin sensitiser Eye irritant Phototoxicant

-

-

General human health issues Possible thyroid toxicant
Endocrine issues - Weak increase of aromatase activity and estrogen production

: Yes, known to cause a problem
: No, known not to cause a problem
: Possibly, status not identified
- : No data found

Handling issues:
Property Click here for information on the parameters used to describe substance handling issues Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with data on handling issues Interpretation Click here for information on the way in which we interpret data on handling issues
General Click here for a description of the International Maritime Dangerous Goods (IMDG) codes Not explosive or oxidising
IMDG Transport Code is usually 6.1
CLP classification 2013 Health: H300
Environment: H400, H410
EC Risk Classification Click here to view information omn the EU risk phrases T+ - Very toxic: R28
N - Dangerous for the environment: R50, R53
EC Safety Classification Click here to view information omn the EU safety phrases S1/2, S22, S36/37, S45, S60, S61
WHO Classification Ib - Highly hazardous
US EPA Classification (formulation) I (oral, eye), II (inhalation), III (dermal) - Danger - Highly toxic, Warning - Moderately toxic, Caution - Slightly toxic
UN Number 2757
Waste disposal & packaging Click here for a description of UN packaging marks Packaging Group II (medium danger)


TRANSLATIONS

for methomyl

Language Name
English methomyl
French methomyl
German Methomyl
Danish methomyl
Italian metomil
Spanish metomilo
Greek methomyl
Slovenian metomil
Polish metomyl
Swedish metomyl
Hungarian metomil
Dutch methomyl

Record last updated: Wednesday 31 October 2018
Contact: aeru@herts.ac.uk