oxydemeton-methyl (Ref: ENT 24964) ** methylmercaptophos oxide ** R 2170 ** isomethylsystox sulfoxide ** metaisosystox sulfoxide ** BAY 21097 ** Translations

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GENERAL INFORMATION
for oxydemeton-methyl

Description: An insecticide and acaricide for the control of insect pests in both food and non-food situations

Example pests controlled: Aphids including the green peach aphid, mustard aphid; Mites; Thrips; Sawflies

Example applications: Vegetables; Fruit; Field crops; Ornamental shrubs and trees

Efficacy & activity: -

Availability status: Current

Introduction & key dates: -

EC Regulation 1107/2009 (repealing 91/414):

Status	Not approved
Dossier rapporteur/co-rapporteur	France
Date inclusion expires	Expired
EU Candidate for substitution (CfS)	-

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

HR

HU

IE

IT

LT

LU

LV

MT

NL

PL

PT

RO

SE

SI

SK

UK

General status:

Pesticide type	Insecticide
Substance group	Organophosphate
Minimum active substance purity	95%
Known relevant impurities	EU dossier - demeton-S-methyl <=3.5% and demeton-S-methyl sulfone <=2%
Substance origin	Synthetic
Mode of action	Systemic with contact and stomach action. Rapid knockdown effect. Cholinesterase inhibitor.
CAS RN	301-12-2
EC number	206-110-7
CIPAC number	171
US EPA chemical code	058702
Isomerism	Chiral, a specific isomer or a derivative of a chiral molecule
Chemical formula	C6H15O4PS2
SMILES	O=S(CCSP(=O)(OC)OC)CC
International Chemical Identifier key (InChIKey)	PMCVMORKVPSKHZ-UHFFFAOYSA-N
International Chemical Identifier (InChI)	InChI=1S/C6H15O4PS2/c1-4-13(8)6-5-12-11(7,9-2)10-3/h4-6H2,1-3H3
Structure diagram/image available?	Yes
Molecular mass (g mol-1)	246.3
PIN (Preferred Identification Name)	-
IUPAC name	S-2-ethylsulfinylethyl O,O-dimethyl phosphorothioate
CAS name	S-(2-(ethylsulfinyl)ethyl) O,O-dimethyl phosphorothioate
Other status information	Potential groundwater contaminant; Chemical subject to PIC regulations
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	Aphis gossypii Myzocallis coryli Myzus persicae
Physical state	Colourless liquid
Related substances & organisms	methyl isobutyl ketone beta-cyfluthrin

Formulations:

Property	Value
Example manufacturers & suppliers of products using this active now or historically	Gowan Amico Pesticides Makhteshim Agan Bayer Mobay
Example products using this active	Metasystox 250EC Oxydemetchem Safasystox
UK LERAP status	No UK approval for use or outside scope
Formulation and application details	Usually supplied as an emsulsifiable concentrate.

ENVIRONMENTAL FATE
for oxydemeton-methyl

Property		Value	Source/Quality Score/Other Information	Interpretation
Solubility - In water at 20oC (mg l-1)		1200000	A5	High
Solubility - In organic solvents at 20oC (mg l-1)		25	A5 - n-Hexane	-
		250000	A5 - Toluene	-
		250000	A5 - 1-Octanol	-
		250000	A5 - Acetone	-
Melting point (oC)		-49	A5	-
Boiling point (oC)		Decomposes before boiling	A5	-
Degradation point (oC)		65	A5	-
Flashpoint (oC)		80.5	A5	-
Octanol-water partition coefficient at pH 7, 20oC	P	1.82 X 10-01	Calculated	-
	Log P	-0.74	A5	Low
Bulk density (g ml-1)/Specific gravity		1.31	A5	-
Dissociation constant (pKa) at 25oC		Not applicable	A5	-
		Note: Not determinable
Vapour pressure at 25oC (mPa)		2	A5	Low volatility
Henry's law constant at 25oC (Pa m3 mol-1)		4.00 X 10-07	A5	Non-volatile
GUS leaching potential index		0.00	Calculated	Low leachability
SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate	Value	9.61 X 10-04	Calculated	-
	Note	-
Potential for particle bound transport index		-	Calculated	Low
Maximum UV-vis absorption L mol-1 cm-1		Maxima at 213nm = 1356	A5	-
Surface tension (mN m-1)		66.0	A5	-

Degradation:

Property		Value	Source/Quality Score/Other Information	Interpretation
General biodegradability		-
Soil degradation (days) (aerobic)	DT50 (typical)	1	K4	Non-persistent
	DT50 (lab at 20oC)	1	A5	Non-persistent
	DT50 (field)	5	A5	Non-persistent
	DT90 (lab at 20oC)	3.32	A5	-
	DT90 (field)	2.66	A5	-
	DT50 modelling endpoint	-	-	-
	Note	EU dossier Lab studies DT50 range 0.4-3.2 days, DT90 range 1.3-10.6 days at 25DegC; Field studies DT50 raneg 1.49-3.82 days, DT90 range 4.9-12.7 days
Dissipation rate RL50 on plant matrix	Value	-	-	-
	Note	-
Dissipation rate RL50 on and in plant matrix	Value	3.6	R4	-
	Note	Published literature RL50 range 3.1-4.0 days, 2 field crops, various matrices, n=2
Aqueous photolysis DT50 (days) at pH 7	Value	222	A5	Stable
	Note	Not significant route of degradation. DT50 187 days daylight, 257 days in dark, pH 5, 38 deg N, Spring
Aqueous hydrolysis DT50 (days) at 20oC and pH 7	Value	73	A5	Moderately persistent
	Note	pH sensitive: DT50 96.3 days at pH 5, 41 days at pH 7, 2.4 days at pH 4, all at 25 degC. 73 days at pH 7 and 20 degC
Water-sediment DT50 (days)		3	A5	Fast
Water phase only DT50 (days)		3	A5	Moderately fast

Soil adsorption and mobility:

Property		Value	Source/Quality Score/Other Information	Interpretation
Linear	Kd	-	DW4	Very mobile
	Koc	10
	Notes and range	-
Freundlich	Kf	0.36	A5	Mobile
	Kfoc	29
	1/n	0.928
	Notes and range	EU dossier Kf range 0.01-0.89 mL/g, kfoc range 2-58 mL/g, 1/n range 0.83-1.14, Soils=4
pH sensitivity		No

Key metabolites:

Metabolite		Formation medium	Estimated maximum occurrence fraction	1107/2009 relevancy
2-ethylsulfinyl ethane sulfonic acid		Soil	0.390	Major fraction, Relevant
2-ethylsulfonyl ethane sulfonic acid		Soil	0.265	Major fraction, Relevant

Other known metabolites:

Metabolite name and reference	Aliases	Formation medium / Rate	Estimated maximum occurrence fraction	Metabolising enzymes
S-[2(ethylsulfonyl)ethyl]O,O-dimethylphoshorothioate	demeton-S-methylsulphon; oxydemeton-methyl metabolite M01	Plant; Soil (Aerobic); Water/sediment	-	-
O-methyl-S-[2(ethylsulfinyl)ethyl] phoshorothioate	oxydemeton-methyl metabolite M06	Plant; Water/sediment	-	-
O-methyl-S-[2(ethylsulfonyl)ethyl] phoshorothioate	oxydemeton-methyl metabolite M07	Plant; Water/sediment	-	-
1-(ethylsulfonyl)-2-(methylsulfonyl) ethane	oxydemeton-methyl metabolite M05	Soil (Aerobic)	-	-
dimethyl phosphate	DMP	Soil (Aerobic); Water	-	-
S-[2(ethylthio)ethyl]O,O-dimethylphoshorothioate. Pesticide common name: demeton-S-methyl	oxydemeton-methyl metabolite M02	Water/sediment	-	-
2-ethylthio ethane sulfonic acid	oxydemeton-methyl metabolite M22	Soil (Anaerobic)	-	-
bis-2-[(ethylsulfinyl)-ethyl]disulfide	oxydemeton-methyl metabolite M11	Water/sediment	-	-
2-ethylsulfinyl-ethyl mercaptan	oxydemeton-methyl metabolite M21	Water/sediment	-	-

ECOTOXICOLOGY
for oxydemeton-methyl

Property		Value	Source/Quality Score/Other Information	Interpretation
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)		48	A5 Rat	High
Mammals - Short term dietary NOEL	(mg kg-1)	0.1	A4 Dog, 1 year	High
	(ppm diet)	-		-
Birds - Acute LD50 (mg kg-1)		34	A5 Colinus virginianus	High
Birds - Short term dietary (LC50/LD50)		361 mg kg bw-1 day-1	A5 Colinus virginianus	-
Fish - Acute 96 hour LC50 (mg l-1)		17	A5 Oncorhynchus mykiss	Moderate
Fish - Chronic 21 day NOEC (mg l-1)		1.8	A5 Oncorhynchus mykiss	Moderate
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1)		0.11	A5 Daphnia magna	Moderate
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1)		0.027	A5 Daphnia magna	Moderate
Aquatic crustaceans - Acute 96 hour LC50 (mg l-1)		-	-	-
Sediment dwelling organisms - Acute 96 hour LC50 (mg l-1)		0.011	A4 Chironomus riparius, 48 hour	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 Scenedemus subspicatus	Low
Algae - Chronic 96 hour NOEC, growth (mg l-1)		-	-	-
Honeybees	Contact acute 48 hour LD50 (μg bee-1)	0.175	A5	High
	Oral acute 48 hour LD50 (μg bee-1)	0.2	A5	High
	Unknown mode acute 48 hour LD50 (μg bee-1)	-	-	-
Earthworms - Acute 14 day LC50 (mg kg-1)		115	A5 Eisenia foetida	Moderate
Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1)		0.41	A4 Eisenia foetida	Moderate
Other soil macro-organisms - e.g. Collembola	LR50 / EC50 / NOEC / % Effect	-	-	-
Other arthropod (1)	LR50 g ha-1	0.375	>, 48 hour A5 Aphidius rhopalosiphi	-
	% Effect	-	-	-
Other arthropod (2)	LR50 g ha-1	11.0	7 day A5 Typhlodromus pyri	-
	% Effect	-	-	-
Soil micro-organisms		Nitrogen mineralisation: No significant adverse effect [Dose: 5 kg ha-1] Carbon mineralisation: No significant adverse effect [Dose: 6 kg ha-1]	A5	-
Mesocosm study data	NOEAEC mg l-1	-	-	-
	NOEAEC mg l-1	-	-	-

HUMAN HEALTH AND PROTECTION
for oxydemeton-methyl

General:

Property		Value	Source/Quality Score/Other Information	Interpretation
Threshold of Toxicological Concern (Cramer Class)		High (class III)	-	-
Mammals - Acute oral LD50 (mg kg-1)		48	A5 Rat	High
Mammals - Dermal LD50 (mg kg-1 body weight)		112	A5 Rat	-
Mammals - Inhalation LC50 (mg l-1)		0.471	A5 Rat	-
Other Mammal toxicity endpoints		-		-
ADI - Acceptable Daily Intake (mg kg-1bw day-1)		0.0003	A5 Rat, SF=100	-
ARfD - Acute Reference Dose (mg kg-1bw day-1)		0.0015	A5 Rat, SF=100	-
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1)		0.001	A5 Rat, SF=100	-
Dermal penetration studies (%)		20.0	A5	-
Dangerous Substances Directive 76/464		List II	-	-
Exposure Limits		-	-	-
Exposure Routes	Public	Possible risk to bystanders
	Occupational	Possible exposure risk during treatment of orchards
European MRLs		Click here for the EU MRL pesticide database
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		Highly toxic

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

Handling issues:

Property		Value	Source/Quality Score/Other Information	Interpretation
General		Not explosive IMDG Transport Code is usually 6.1
CLP classification 2013		Health: H301, H311 Environment: H400
EC Risk Classification		T - Toxic: R24/25 N - Dangerous for the environment: R50
EC Safety Classification		S1/2, S23, S36/37, S45, S61
WHO Classification		Ib	-	Highly hazardous
US EPA Classification (formulation)		No consensus across products or no products available	-	-
UN Number		3018
Waste disposal & packaging		Packaging Group II (medium danger)

TRANSLATIONS
for oxydemeton-methyl

Language	Name
English	oxydemeton-methyl
French	oxydemeton-methyle
German	Oxydemeton-methyl
Danish	oxydemeton-methyl
Italian	ossidemeton-metil
Spanish	oxidemeton metil
Greek	oxydemeton-methyl
Slovenian	oksidemeton metil
Polish	oksydemeton metylu
Swedish	-
Hungarian	oxidemeton-methyl
Dutch	oxydemeton-methyl

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Record last updated: Thursday 18 January 2018
Contact: aeru@herts.ac.uk