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Methoxychlor (Ref: OMS 466)
Last updated: 18/01/2023
(Also known as: methoxychlore; dimethoxy-DT; dianisyl trichloroethane; ENT 1716; DMDT)
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
General insect control on domestic cats and dogs and on farmed animals
Availability status
Current
Introduction & key dates
circa 1948
Examples of species treated
Cats and dogs; Cattle, Horses
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
-
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
Veterinary substance type
Insecticide
Substance groups
Organochloride insecticide
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. Sodium channel modulator.
Molecular targets
-
CAS RN
72-43-5
EC number
200-779-9
CIPAC number
14
US EPA chemical code
034001
PubChem CID
4115
CLP index number
No data found
ATCvet Code
-
Therapeutic Class
-
Controlled Drug?
-
Regulation 37/2010 MRL Classification
-
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
-
Physical state
Colourless crystalline solid
Formulations
Property
Product
Manufacturer
Authorisation Route
UK Legal Class
Example products using this active
- - - -
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
Fat solubility of residues
Solubility
Soluble
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 -
Data type
Observed in metabolism and farm animal feeding studies
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 -
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)
- - -
Refractive Index
- - -
Degradation
Property
Value
Source; quality score; and other information
Interpretation
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)
- - -
Note
Best available data
Manure DT₅₀ (days)
- - -
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
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 -
Known soil metabolites
Metabolite
Major/Minor fraction
Estimated maximum occurrence fraction
Notes
1,1-(2,2-dichloroethylidene)bis(4-methoxybenzene)
- - -
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)
> 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)
- - -
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
- - -
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
- - -
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)
> 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
Apis mellifera		 Moderate
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
5.0
K3 K = Research datasets, e.g. Pandora, Demetra
3 = Unverified data of known source
Apis mellifera		 Moderate
Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
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)
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)
36.7
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
Chironomus dilutus as 10d LC₅₀		 Moderate
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)
- - -
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)
- - -
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
-
Mammalian dose elimination route and rate
- - -
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
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: 18/01/2023
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