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Chlormephos (Ref: MC 2188)
(Also known as: chlormethylfos; chlormefos)
SUMMARY
Chlormephos is an organophosphorus insecticide. It has a moderate aqueous solubility and is not volatile. based on its chemical properties it would not normally be expected to leach to groundwater. It is not normally persistent in soil systems. It is highly toxic to mammals if ingested, inhaled or absorbed through skin , a cholinesterase inhibitor and a neurotoxciant. Ecotoxicology data is sparse but chlormephos is highly toxic to honey bees and moderately toxic to birds, fish and earthworms.
Data alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement.

Environmental fate Ecotoxicity Human health
Environmental fate
Moderate alert:
Drainflow: Slightly mobile; Potential for particle bound transport: Medium
Warning:
Significant data are missing
Ecotoxicity
High alert:
Bees acute unknown ecotoxicity: High
Warning:
Significant data are missing
Human health
High alert:
Mammals acute toxicity: High; Acetyl cholinesterase inhibitor; Neurotoxicant
Warning:
Significant data are missing
GENERAL INFORMATION
Description
An insecticide used to control a wide range of foliage and soil dwelling pests
Example pests controlled
Wireworms; Millipedes; Symphylids; Mealybugs; Cutowrms; Whiteflies, Leaf rollers; Caperpillars; Scale insects; Grasshoppers; Apple moth; Earwigs; Beetles; Borers
Example applications
Maize; Sugarbeet; Fruit including apples, pears, avocado, grapes, mango, citrus. kiwi; Vegetables; Cereals; Pasture
Efficacy & activity
-
Availability status
-
Introduction & key dates
circa 1973
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
Not applicable
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
                 
Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries
ISIceland
NONorway
                 
Additional information
Also used in
-
Chemical structure
Isomerism
None
Chemical formula
C₅H₁₂ClO₂PS₂
Canonical SMILES
CCOP(=S)(OCC)SCCl
Isomeric SMILES
No data
International Chemical Identifier key (InChIKey)
QGTYWWGEWOBMAK-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C5H12ClO2PS2/c1-3-7-9(10,8-4-2)11-5-6/h3-5H2,1-2H3
2D structure diagram/image available?
Yes
General status
Pesticide type
Insecticide
Substance groups
Organophosphate insecticide; Organothiophosphate insecticide
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Non-systemic with contact and stomach action. Acetylcholine esterase inhibitor.
CAS RN
24934-91-6
EC number
246-538-1
CIPAC number
337
US EPA chemical code
295300
PubChem CID
32739
CLP index number
015-114-00-6
Molecular mass
234.70
PIN (Preferred Identification Name)
S-(chloromethyl) O,O-diethyl phosphorodithioate
IUPAC name
S-chloromethyl O,O-diethyl phosphorodithioate
CAS name
S-(chloromethyl) O,O-diethyl phosphorodithioate
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)
1B
Fungicide Resistance Classification (FRAC)
Not applicable
Examples of recorded resistance
None identified
Physical state
Colourless liquid
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Bayer CropScience
  • Rhone Poulenc
  • Murphy
Example products using this active
  • Dotan
Formulation and application details
Usually supplied in a granular formulations
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
60
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)
Miscible
V2 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
2 = Unverified data of unknown source
Acetone		 -
Miscible
V2 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
2 = Unverified data of unknown source
Methanol		 -
Miscible
V2 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
2 = Unverified data of unknown source
Ethanole		 -
Miscible
V2 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
2 = Unverified data of unknown source
Xylene		 -
Melting point (°C)
- - -
Boiling point (°C)
- - -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
1.10 X 1003 Calculated -
Log P
3.04
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
 High
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
1.26
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)
0.0076
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)
2.97 X 1001
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
 Moderately 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)
20
W4 W = French database provided by ARVALIS-Institut du Végétal. Dataset no longer available.
4 = Verified data
 Non-persistent
DT₅₀ (lab at 20 °C)
- - -
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
Other sources: DT₅₀ 28 days, sandy soil (R4)
Dissipation rate RL₅₀ on plant matrix
Value
- - -
Note
-
Dissipation rate RL₅₀ on and in plant matrix
Value
- - -
Note
-
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
-
V1 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
1 = Estimated data with little or no verification
 Slightly mobile
Koc
1100
Notes and range
Estimated
Freundlich
Kf
- - -
Kfoc
-
1/n
-
Notes and range
-
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
1.25 Calculated Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
2.49 X 10-02 Calculated -
Note
-
Potential for particle bound transport index
Medium Calculated -
Potential for loss via drain flow
Slightly mobile Calculated -
Bio-concentration factor
BCF (l kg⁻¹)
120
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
Whole fish		 Threshold for concern
CT₅₀ (days)
Not available -
Known soil metabolites
Metabolite
Major/Minor fraction
Estimated maximum occurrence fraction
Notes
ethion (Ref: ENT 24105)
- - -
Known groundwater metabolites

None

Other known metabolites

None
ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 7
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)
-
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat		 -
(ppm diet)
> 0.39 -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
260
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Coturnix japonica		 Moderate
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
- - -
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
> 1.0
R4 R = Peer reviewed scientific publications
4 = Verified data
Eisenia andrei as LOEC		 Moderate
Soil micro-organisms
- - -
Collembola
Acute LC₅₀ (mg kg⁻¹)
- - -
Chronic NOEC (mg kg⁻¹)
- - -
Non-target plants
- - -
- - -
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)
> 0.9
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
 High
Chronic
- - -
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 bee species (1)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Other bee species (2)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Beneficial insects (Ladybirds)
- - -
Beneficial insects (Lacewings)
- - -
Beneficial insects (Parasitic wasps)
- - -
Beneficial insects (Predatory mites)
- - -
Beneficial insects (Ground beetles)
- - -
Aquatic ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
2.5
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
Rasbora heteromorpha		 Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
- - -
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)
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
- - -
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
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)
> 7
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)
7.0
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (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
List I; List II - -
Exposure Routes
Public
-
Occupational
May be absorbed through dermal contact
MRLs
European
EU MRL pesticide database 
Great Britain
GB MRL Register 
Notes
-
Drinking Water Standards
- - -
Drinking Water MAC (μg l⁻¹)
- - -
Mammalian dose elimination route and rate
Eliminated within 24hrs via urine
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
 -
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
 No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
No data found
✓Yes, known to cause a problem
✓Yes, known to cause a problem
Respiratory tract irritant Skin irritant Skin sensitiser
✓Yes, known to cause a problem
 No data found No data found
Eye irritant Phototoxicant  
No data found No data found  
General human health issues
Very toxic if ingested, inhaled or absorbed through skin
Handling issues
Property
Value and interpretation
General
IMDG Transport Hazard Class 6.1
CLP classification 2013
Health: H300, H310
Environment: H400, H410
WHO Classification
Ia (Extremely hazardous)
UN Number
UN3018
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
chlormephos
French
chlorméphos
German
Chlormephos
Danish
chlormephos
Italian
clormefos
Spanish
clormefos
Greek
chlormephos
Polish
chloromefos
Swedish
-
Hungarian
-
Dutch
chloormefos
Norwegian
-
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