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methamidophos (Ref: ENT 27396)
** acephate-metabolite ** SRA 5172 ** BAY 71628 ** Translations

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

GENERAL INFORMATION
for methamidophos

Description: An insecticide and acaricide used to control chewing and sucking pests. Also a pesticide transformation product

Introduction: circa 1972

EC Regulation 1107/2009 (repealing 91/414):
Status Not approved
Dossier rapporteur/co-rapporteur Italy
Date inclusion expires Expired

Approved for use () or known to be used () in the following European countries:

AT

BE

BG

CY

CZ

DE

DK

EE

EL

ES

FI

FR

HU

IE

IT

LT

LU

LV

MT

NL

PL

PT

RO

SE

SI

SK

UK

Also registered in: Australia, USA

General status:
Pesticide type Insecticide, Acaricide, Metabolite
Metabolite Type Soil
Substance group Organophosphate
Substance origin Synthetic
Mode of action Systemic with contact and stomach action. Acetylcholinesterase (AChE) inhibitor.
CAS RN 10265-92-6
EC number 233-606-0
CIPAC number 355
US EPA chemical code 101201
Chiral molecule Chiral or specific isomer of chiral molecule
Chemical formula C2H8NO2PS
SMILES O=P(OC)(SC)N
International Chemical Identifier (InChI) InChI=1/C2H8NO2PS/c1-5-6(3,4)7-2/h1-2H3,(H2,3,4)
Structure diagram/image available? Yes
Molecular mass (g mol-1) 141.13
PIN (Preferred Identification Name) -
IUPAC name (RS)-(O,S-dimethyl phosphoramidothioate)
CAS name O,S-dimethyl phosphoramidothioate
Other status information PIC Annex III; Marine Pollutant; Rotterdam Convention (Class Ib)
Herbicide Resistance Classification (HRAC) Not applicable
Insecticide Resistance Classification (IRAC) 1B
Fungicide Resistance Classification (FRAC) Not applicable
Physical state Off-white crystalline solid
Related substances & organisms -

Can be a metabolite of:
Parent Formation medium Estimated maximum occurrence fraction 91/414 relevancy
acephate Soil     -

Formulations:
Property Value
Example manufacturers & suppliers of products using this active
  • Bayer CropScience
  • AgroCare
  • United Phosphorus
Example products using this active
  • Tahmabon
  • Patrole
  • Pillaron
  • Monitor
UK LERAP status No UK approval for use or outside scope
Formulation and application details Usually supplied as a soluble concentrate.


ENVIRONMENTAL FATE

for methamidophos

Property Value Source/Quality Score/Other Information Interpretation
Solubility - In water at 20oC (mg l-1) 200000 K4 High
Solubility - In organic solvents at 20oC (mg l-1) 200000 C4 - Acetone -
1000 C4 - Hexane -
3500 C4 - Toluene -
200000 C4 - Dichloromethane -
Melting point (oC) 45 L3 -
Boiling point (oC) Decomposes before boiling L3 -
Degradation point (oC) 160 L3 -
Flashpoint (oC) 212 Q2 -
Octanol-water partition coefficient at pH 7, 20oC P 1.62 X 10-01 Calculated -
Log P -0.79 H4 Low
Bulk density (g ml-1)/Specific gravity 1.27 L3 -
Dissociation constant (pKa) at 25oC - - -
Note:
Vapour pressure at 25oC (mPa) 2.3 L3 Intermediate state
Henry's law constant at 25oC (Pa m3 mol-1) 1.60 X 10-06 L3 Non-volatile
Henry's law constant at 20oC (dimensionless) 1.10 X 10-09 K3 Non-volatile
GUS leaching potential index 2.18 Calculated Transition state
SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate Value 4.23 X 10-03 Calculated -
Note -
Potential for particle bound transport index - Calculated Low
Maximum UV-vis absorption L mol-1 cm-1 - - -
Surface tension (mN m-1) - - -

Degradation:
Property Value Source/Quality Score/Other Information Interpretation
Soil degradation (days) (aerobic) DT50 (typical) 3.5 K4 Non-persistent
DT50 (lab at 20oC) 4 Y4 Non-persistent
DT50 (field) 4 H4 Non-persistent
DT90 (lab at 20oC) - - -
DT90 (field) - - -
Note Other sources: DT50 6 days (DW4); 1.9 days (F3)
Aqueous photolysis DT50 (days) at pH 7 Value 90 C4 Stable
Note Insignificant degradation route
Aqueous hydrolysis DT50 (days) at 20oC and pH 7 Value 5 C4 Non-persistent
Note -
Water-sediment DT50 (days) 23.5 K3 Fast
Water phase only DT50 (days) 16 K3 Slow

Soil adsorption and mobility:
Property Value Source/Quality Score/Other Information Interpretation
Linear Kd - H3 Very mobile
Koc 1.0
Notes and range Other sources: 5.0 mL/g (DW3)
Freundlich Kf 0.03 F4 -
Kfoc -
1/n 0.64
Notes and range Clay loam, OM=3.3%, pH=5.8
pH sensitivity -


ECOTOXICOLOGY

for methamidophos

Property Value Source/Quality Score/Other Information Interpretation
Bio-concentration factor BCF 75 Q2 Estimated Low potential
CT50 (days) Not available -
Bioaccumulation potential - Calculated Low
Mammals - Acute oral LD50 (mg kg-1) 30 F4 Rat High
Mammals - Short term dietary NOEL (mg kg-1) 0.1 L2 Rat, 2 year High
(ppm diet) - -
Birds - Acute LD50 (mg kg-1) 10 G4 Colinus virginianus High
Birds - Short term dietary (LC50/LD50) - - -
Fish - Acute 96 hour LC50 (mg l-1) > 25 G4 Oncorhynchus mykiss Moderate
Fish - Chronic 21 day NOEC (mg l-1) - - -
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) > 0.27 L3 Daphnia magna Moderate
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) - - -
Aquatic crustaceans - Acute 96 hour LC50 (mg l-1) > 1.05 F3 Americamysis bahia Moderate
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) 178 L3 Scenedemus subspicatus Low
Algae - Chronic 96 hour NOEC, growth (mg l-1) - - -
Honeybees - Acute 48 hour LD50 (μg bee-1) > 0.22 K4 Oral High
Earthworms - Acute 14 day LC50 (mg kg-1) 34 L3 Eisenia foetida Moderate
Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1) - - -
Other soil macro-organisms - e.g. Collembola LR50 / EC50 / NOEC / % Effect - - -
Other arthropod (1) LR50 g ha-1 - - -
% Effect Harmful Dose: 900 g ha-1
AA3 Typhlodromus pyri
Harmful
Other arthropod (2) LR50 g ha-1 - - -
% Effect Harmful Dose: 900 g ha-1
AA3 Chrysoperla carnea
Harmful
Soil micro-organisms - - -
Mesocosm study data NOEAEC mg l-1 - - -
NOEAEC mg l-1 - - -


HUMAN HEALTH AND PROTECTION

for methamidophos

General:
Property Value Source/Quality Score/Other Information Interpretation
Mammals - Acute oral LD50 (mg kg-1) 30 F4 Rat High
Mammals - Dermal LD50 (mg kg-1 body weight) 69.0 L3 Rabbit -
Mammals - Inhalation LC50 (mg l-1) 0.213 L3 Rat -
Other Mammal toxicity endpoints - -
ADI - Acceptable Daily Intake (mg kg-1bw day-1) 0.004 JMPR 1990 -
ARfD - Acute Reference Dose (mg kg-1bw day-1) 0.01 JMPR 2003 -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) - - -
Dermal penetration studies (%) - - -
Dangerous Substances Directive 76/464 List I; List II - -
Exposure Limits - - -
Exposure Routes Public -
Occupational Can be absorbed following ingestion, inhalation and skin contact
Examples of European MRLs (mg kg-1) Value Beans (with pods) and peas (with pods): 0.5; Apricots: 0.1; Nectarins and peaches: 0.05; Brussel sprouts and cauliflowers: 0.02; Beans (edible part), peas (edible part), other vegetables, other fruit and cereal grains: 0.01
Note Current May 2007.
For the EU pesticides database click here
Drinking Water MAC (μg l-1) - - -

Health issues:
Carcinogen Mutagen Endocrine disrupter Reproduction / development effects Cholinesterase inhibitor Neurotoxicant Respiratory tract irritant Skin irritant Eye irritant

-

General human health issues Highly toxic

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

Handling issues:
Property Value Source/Quality Score/Other Information Interpretation
General Prevent generation of dust
IMDG Transport Code is 6.1
CLP classification 2013 -
EC Risk Classification T+ - Very toxic: R26/28
T - Toxic: R24
N - Dangerous for the environment: R50
EC Safety Classification S1/2, S28, S46, S36/37, S61
WHO Classification Ib - Highly hazardous
US EPA Classification (formulation) No consensus across products or no products available - -
UN Number 2783
Waste disposal & packaging -


TRANSLATIONS

for methamidophos

Language Name
English methamidophos
French methamidophos
German Methamidophos
Danish methamidophos
Italian metamidofos
Spanish metamidofos
Greek methamidophos
Slovenian metamidofos
Polish metamidofos
Swedish -
Hungarian metamidofosz
Dutch methamidofos

Record last updated: Monday 29 July 2013
Contact: aeru@herts.ac.uk