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Methoxychlor (Ref: OMS 466)
Last updated: 19/02/2021
(Also known as: methoxychlore; dimethoxy-DT; dianisyl trichloroethane; ENT 1716; DMDT)

SUMMARY
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
High alert:
Persistent; Potential for particle bound transport: High
Ecotoxicity
High alert:
Fish acute ecotoxicity: High; Daphnia acute ecotoxicity: High; Daphnia chronic ecotoxicity: High
Human health
High alert:
Endocrine distrupter; Neurotoxicant
GENERAL INFORMATION
Description
An insecticide effective against a wide range of pests encountered in agricultural (crops and livestock), horticulture and domestic situations
Example pests controlled
Flies, Mosquitoes; Cockroaches; Chiggers
Example applications
Liverstock pest control; Domestic gardens; Pet pest management
Efficacy & activity
-
Availability status
Current
Introduction & key dates
circa 1948
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
-
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
                 
Also used in
Also used in
USA
Chemical structure
Isomerism
A prochiral molecule
Chemical formula
C₁₆H₁₅Cl₃O₂
Canonical SMILES
COC1=CC=C(C=C1)C(C2=CC=C(C=C2)OC)C(Cl)(Cl)Cl
Isomeric SMILES
No data
International Chemical Identifier key (InChIKey)
IAKOZHOLGAGEJT-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C16H15Cl3O2/c1-20-13-7-3-11(4-8-13)15(16(17,18)19)12-5-9-14(21-2)10-6-12/h3-10,15H,1-2H3
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
methoxychlor -
General status
Pesticide type
Insecticide, Veterinary substance
Substance group
Organochlorine
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Contact and stomach action. Central nervous stimulant, producing hyperactivity, convulsions and death.
CAS RN
72-43-5
EC number
200-779-9
CIPAC number
14
US EPA chemical code
034001
PubChem CID
4115
Molecular mass
345.65
PIN (Preferred Identification Name)
-
IUPAC name
1,1,1-trichloro-2,2-bis(4-methoxyphenyl)ethane
CAS name
1,1'-(2,2,2-trichloroethylidene)bis(4-methoxybenzene)
Other status information
POP candidate; OSPAR pfa
Relevant Environmental Water Quality Standards
-
Herbicide Resistance Classification (HRAC)
Not applicable
Herbicide Resistance Classification (WSSA)
Not applicable
Insecticide Resistance Classification (IRAC)
3B
Fungicide Resistance Classification (FRAC)
Not applicable
Examples of recorded resistance
Ctenocephalides felis, Cydia pomonella, Euxoa ochrogaster, Haematobia irritans, Helicoverpa zea, many more
Physical state
Colourless crystalline solid
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Double-M
  • Chemform
  • Moxie
  • Marlate
Example products using this active
  • Kincaid Enterprises
Formulation and application details
Supplied in a variety of formulations including emulsifiable concentrates, wettable powders, flowables, seed treatments and aerosols
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
0.1
G4 G = Extension Toxicology network database EXTOXNET (click here )
4 = Verified data
Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)
440000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Xylene
-
50000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Methanol
-
700000
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Trichloroethane
-
1333000
V2 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
2 = Unverified data of unknown source
Dichloromethane
-
Melting point (°C)
87
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
-
Boiling point (°C)
- - -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
6.76 X 1005 Calculated -
Log P
5.83
Q2 Q = Miscellaneous internet resources
2 = Unverified data of unknown source
High
Bulk density (g ml⁻¹)
1.41
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)
0.08
Q2 Q = Miscellaneous internet resources
2 = Unverified data of unknown source
Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
2.00 X 10-02
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Non-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)
120
G4 G = Extension Toxicology network database EXTOXNET (click here )
4 = Verified data
Persistent
DT₅₀ (lab at 20 °C)
120
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
Persistent
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
Best available data
Dissipation rate RL₅₀ on plant matrix
Value
6.5
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
-
Note
Cherry leaves, n=1
Dissipation rate RL₅₀ on and in plant matrix
Value
1.8
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
-
Note
Collard leaves, n=1
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
-
G3 G = Extension Toxicology network database EXTOXNET (click here )
3 = Unverified data of known source
Non-mobile
Koc
80000
Notes and range
Best available data
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
-1.88 Calculated Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
5.35 X 10-03 Calculated -
Note
Estimated concentrations of chemicals with Koc values greater than 9995 ml g⁻¹ are beyond the scope of the regression data used in SCI-GROW development. If there are concerns for such chemicals, a higher tier groundwater exposure assessment should be considered, regardless of the concentration returned by SCI-GROW
Potential for particle bound transport index
High Calculated -
Potential for loss via drain flow
Non-mobile Calculated -
Key metabolites
Metabolite
Formation medium
Estimated maximum occurrence fraction
1107/2009 relevancy
1,1-(2,2-dichloroethylidene)bis(4-methoxybenzene)
Soil - -
ECOTOXICOLOGY
Property
Value
Source; quality score; and other information
Interpretation
Bio-concentration factor
BCF (l kg⁻¹)
1622
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
(Other literature values Log BCF range 2.8-4.1 (R3))
Threshold for concern
CT₅₀ (days)
Not available -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 6000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
Low
Mammals - Short term dietary NOEL
(mg kg⁻¹)
-
L2 L = Pesticide manuals and hard copy reference books / other sources
2 = Unverified data of unknown source
Rat 2 year
-
(ppm diet)
200 -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
> 2000
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
Low
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
0.052
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Oncorhynchus mykiss
High
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
0.00078
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Daphnia magna
High
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
0.001
P3 P = Other governments and regulators
3 = Unverified data of known source
Daphnia magna
High
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)
0.6
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
Scenedesmus quadricauda
Moderate
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)
> 23.6
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
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)
- - -
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 pollinators (1)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Other pollinators (2)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
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)
> 6000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
Low
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
2000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rabbit
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
- - -
Other Mammal toxicity endpoints
- - -
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
0.1
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
JMPR 1977
-
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
-
MRLs
European
EU MRL pesticide database 
Notes
-
Drinking Water Standards
Non-statutory WHO drinking water guideline 0.02 mg l⁻¹
B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
5 = Verified data used for regulatory purposes
UK EA QS database 2018
-
Drinking Water MAC (μg l⁻¹)
- - -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
?Possibly, status not identified
A3 A = Chromosome aberration (EFSA database)
3 = Negative
;
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
;
E3 E = Unspecified genotoxicity type (miscellaneous data source)
3 = Negative
Yes, known to cause a problem
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
?Possibly, status not identified
XNo, known not to cause a problem
Yes, known to cause a problem
Respiratory tract irritant Skin irritant Skin sensitiser
No data found
Yes, known to cause a problem
No data found
Eye irritant Phototoxicant  
Yes, known to cause a problem
No data found  
General human health issues
Endocrine issues - Strong estrogenic effect
Potential kidney & liver toxicant
IARC Group 3 carcinogen
Handling issues
Property
Value and interpretation
General
Highly flammable and easily ignited by heat, sparks and flames
CLP classification 2013
Health: H302, H312, H332, H351, H371
Environment: H400
EC Risk Classification
Not classified: Obsolete
EC Safety Classification
Not classified: Obsolete
WHO Classification
U (Unlikely to present an acute hazard)
UN Number
2761
Waste disposal & packaging
-
TRANSLATIONS
Language
Name
English
methoxychlor
French
methoxychlore
German
Methoxychlor
Danish
methoxychlor
Italian
metossicloro
Spanish
metoxiclor
Greek
-
Polish
metoksychlor
Swedish
-
Hungarian
-
Dutch
-

Record last updated: 19/02/2021
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