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Demeton (Ref: ENT 17295)
Last updated: 20/06/2019
(Also known as: E 1059; mercaptophos)

SUMMARY
Demeton is an organophosphate insecticide that is not approved for use in the EU. It has a high aqueous solubility and is highly volatile. There are considerable gaps in literature regarding its environmental fate. Demeton is highly toxic to mammals, is a neurotoxin and may also adversely affect reproduction and/or development. It is also an acetyl cholinesterase inhibitor. It is highly toxic to birds and aquatic invertebrates. It moderately toxic to fish and honeybees.
GENERAL INFORMATION
Description
An insecticide used to control sucking insects on a range of crops
Example pests controlled
Aphids; Sawflies; Spidermites; Thrips
Example applications
Fruit; Vegetables; Potatoes; Cereals; Ornamentals; Tree nuts
Efficacy & activity
-
Availability status
Obsolete
Introduction & key dates
-
UK regulatory status
UK approval status
Not approved
EC Regulation 1107/2009 (repealing 91/414)
EC Directive 91/414 Status
Not approved
Dossier rapporteur/co-rapporteur
Not applicable
Date inclusion expires
Expired
EU Candidate for substitution (CfS)
Not applicable
Listed in EU database
No
Approved for use (✓) or known to be used (#) in the following EU-27 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
Demeton is a mixture of thiol and thiono isomers
Chemical formula
C₈H₁₉O₃PS₂
Canonical SMILES
CCOP(=S)(OCC)OCCSCC
Isomeric SMILES
No data
International Chemical Identifier key (InChIKey)
DGLIBALSRMUQDD-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/2C8H19O3PS2/c1-4-10-12(9,11-5-2)14-8-7-13-6-3;1-4-9-12(13,10-5-2)11-7-8-14-6-3/h2*4-8H2,1-3H3
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
Systemic with contact and stomach action. Acetylcholinesterase (AChE) inhibitor.
CAS RN
8065-48-3
EC number
-
CIPAC number
-
US EPA chemical code
057601
PubChem CID
24722
Molecular mass
258.34
PIN (Preferred Identification Name)
reaction mixture of O,O-diethyl O-[2-(ethylsulfanyl)ethyl] phosphorothioate and O,O-diethyl S-[2-(ethylsulfanyl)ethyl] phosphorothioate
IUPAC name
reaction mixture of O,O-diethyl O-2-ethylthioethyl phosphorothioate and O,O-diethyl S-2-ethylthioethyl phosphorothioate
CAS name
O,O-diethyl O-(2-(ethylthio)ethyl) phosphorothioate mixture with O,O-diethyl S-(2-(ethylthio)ethyl) phosphorothioate
Other status information
-
Relevant Environmental Water Quality Standards
UK Statutory standard for the protection of aquatic life in inland, coastal and territorial waters: 0.5 µg l⁻¹ as annual average
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 fabae, Myzus persicae, Tetranychus urticae, Tetranychus viennensis, Aphis gossypii, Liriomyza trifolii, many others
Physical state
Bright yellow oil
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Demox
  • Systemox
  • Systox
Example products using this active
  • Bayer
  • Mobay
UK LERAP status
No UK approval for use as a pesticide under EC Regulation 1107/2009
Formulation and application details
Formulated as an emulsifiable concentrate.
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
666
V2 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
2 = Unverified data of unknown source
(varies significantly with isomer)
High
Solubility - In organic solvents at 20 °C (mg l⁻¹)
- - -
Melting point (°C)
-25
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
-
Boiling point (°C)
125
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
-
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
1.62 X 1003 Calculated -
Log P
3.21
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
High
Bulk density (g ml⁻¹)
1.126
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
-
Dissociation constant pKa) at 25 °C
- - -
-
Vapour pressure at 20 °C
36.26
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
Highly volatile
Henry's law constant at 25 °C
0.387 - Moderately volatile
GUS leaching potential index
- - -
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
Cannot be calculated - -
Note
-
Potential for particle bound transport index
- - -
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)
- - -
DT₅₀ (lab at 20 °C)
- - -
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
-
Dissipation rate RL₅₀ on plant matrix
Value
7.8
R4 R = Peer reviewed scientific publications
4 = Verified data
-
Note
Published literature RL₅₀ range 3.9-11.5 days, leaves of 6 field crops, n=5
Dissipation rate RL₅₀ on and in plant matrix
Value
11.7
R4 R = Peer reviewed scientific publications
4 = Verified data
-
Note
Published literature RL₅₀ range 4.8-30.0 days, various matrices from of 6 field crops, n=6
Aqueous photolysis DT₅₀ (days) at pH 7
Value
- - -
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
- - -
Note
-
Water-sediment DT₅₀ (days)
- - -
Water phase only DT₅₀ (days)
- - -
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
- - -
Koc
-
Notes and range
-
Freundlich
Kf
- - -
Kfoc
-
1/n
-
Notes and range
-
pH sensitivity
-
ECOTOXICOLOGY
Property
Value
Source; quality score; and other information
Interpretation
Bio-concentration factor
BCF (l kg⁻¹)
- - -
CT₅₀ (days)
- -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
2.5
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
Rat
High
Mammals - Short term dietary NOEL
(mg kg⁻¹)
- - -
(ppm diet)
- -
Birds - Acute LD₅₀ (mg kg⁻¹)
7.18
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
Anas platyrhynchos
High
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
1.6
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
Oncorhynchus mykiss
Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
0.0104
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
Daphnia pulex
High
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
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)
- - -
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)
- - -
Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
> 2.6
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
Bumblebees (Bombus spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
> 1.0
R4 R = Peer reviewed scientific publications
4 = Verified data
Bombus lucorum 24 hr
Moderate
-
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)
0.076
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)
0.026
R4 R = Peer reviewed scientific publications
4 = Verified data
Nomia melanderi
High
Mode of exposure
Contact
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
- - -
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)
2.5
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
Rat
High
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
8.2
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
Rat
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
- - -
Other Mammal toxicity endpoints
- - -
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
- - -
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
- - -
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
- - -
Exposure Routes
Public
-
Occupational
May be absorbed from the gastrointestinal tract, skin, and by inhalation
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
No data found
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
;
E0 E = Unspecified genotoxicity type (miscellaneous data source)
0 = No data
XNo, known not to cause a problem
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
Yes, known to cause a problem
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
No further information available
Handling issues
Property
Value and interpretation
General
No information available
CLP classification 2013
-
EC Risk Classification
Not classified: Obsolete
EC Safety Classification
Not classified: Obsolete
WHO Classification
O (Obsolete substance)
UN Number
-
Waste disposal & packaging
-
TRANSLATIONS
Language
Name
English
demeton
French
demeton
German
Demeton
Danish
demeton
Italian
demeton
Spanish
demeton
Greek
demeton
Polish
demeton
Swedish
demeton
Hungarian
demeton
Dutch
demeton

Record last updated: 20/06/2019
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