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Dicofol (Ref: ENT 23648)
Last updated: 21/08/2024
(Also known as: kelthane; FW-293; decofol; DTMC)

SUMMARY
Dicofol is an organochloride acaricide. It has a low aqueous solubility, volatile and, based on its chemical properties, is unlikely to leach to groundwater. It is moderately persistent in soils but does not normally persist in water. It is moderately toxic to mammals and has a high tendency to bioaccumulate. Dicofol is also an irritant and neurotoxin. It has a moderate toxicity to most biodiversity including honeybees 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
High alert:
Potential for particle bound transport: High
Ecotoxicity
High alert:
Fish chronic ecotoxicity: High
Human health
High alert:
Endocrine disrupter; Neurotoxicant
GENERAL INFORMATION
Description
An acaricide used to control many species of phytophagous mite on a range of food and ornamental crops
Example pests controlled
Various mites including Pacific mite; two-spotted spider mite, tropical mites, tomato russet mite, citrus mite, European red mite
Example applications
Vegetables including beans, squash, peppers; Cotton; Cucumbers; Hops; Fruit including apples, pears, citrus, grapes
Efficacy & activity
-
Availability status
Current
Introduction & key dates
1956, first reported; 1957, first marketed USA
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
Spain
Date EC 1107/2009 inclusion expires
Expired
EU Candidate for substitution (CfS)
Not applicable
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
Isomeric - the o,p'-substituted isomer is chiral and may have enantiomer-specific activity but, the stereospecific activity of o,p'-dicofol has not been reported.
Chemical formula
C₁₄H₉Cl₅O
Canonical SMILES
C1=CC(=CC=C1C(C2=CC=C(C=C2)Cl)(C(Cl)(Cl)Cl)O)Cl
Isomeric SMILES
Clc1ccc(cc1)C(O)(c2ccc(Cl)cc2)C(Cl)(Cl)Cl
International Chemical Identifier key (InChIKey)
UOAMTSKGCBMZTC-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C14H9Cl5O/c15-11-5-1-9(2-6-11)13(20,14(17,18)19)10-3-7-12(16)8-4-10/h1-8,20H
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
dicofol -
General status
Pesticide type
Acaricide
Substance groups
Organochloride insecticide; Organochloride acaricide; Bridged diphenyl insecticide; Bridged diphenyl acaricide
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Non-systemic with contact action. CNS toxin.
CAS RN
115-32-2
EC number
204-082-0
CIPAC number
123
US EPA chemical code
10501
PubChem CID
8268
CLP index number
603-044-00-4
Molecular mass
370.49
PIN (Preferred Identification Name)
2,2,2-trichloro-1,1-bis(4-chlorophenyl)ethan-1-ol
IUPAC name
2,2,2-trichloro-1,1-bis(4-chlorophenyl)ethanol
CAS name
4-chloro-α-(4-chlorophenyl)-α-(trichloromethyl)benzenemethanol
Other status information
POP candidate; OSPAR pfa/soc; Chemical subject to PIC regulations
Relevant Environmental Water Quality Standards
-
Herbicide Resistance Class (HRAC MoA class)
Not applicable
Herbicide Resistance Class (WSSA MoA class)
Not applicable
Insecticide Resistance Class (IRAC MoA class)
UN
Fungicide Resistance Class (FRAC MOA class)
Not applicable
Examples of recorded resistance
Panonychus citri, Tetranychus arabicus, Tetranychus kanzawai, Tetranychus urticae, many others
Physical state
White crystals
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Agan Chemical
  • Makhteshim-Agan
  • Rohm & Hass
  • Sedagri
Example products using this active
  • Carbax
  • Mitigan
  • Acarin
  • Mitex
  • kelthane
  • Hilfol
Formulation and application details
Usually supplied as emulsifiable concentrates and wettable powders
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
0.8
B5 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here )
5 = Verified data used for regulatory purposes
Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)
2600000
C4 C = AGRITOX dataset. Dataset is no longer available.
4 = Verified data
Dichloromethane
-
2750000
C4 C = AGRITOX dataset. Dataset is no longer available.
4 = Verified data
Methanol
-
1350000
C4 C = AGRITOX dataset. Dataset is no longer available.
4 = Verified data
Xylene
-
400000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Acetone
-
Melting point (°C)
370.5
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
-
Boiling point (°C)
193
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Degradation point (°C)
- - -
Flashpoint (°C)
193
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
(open cup)
-
Octanol-water partition coefficient at pH 7, 20 °C
P
2.00 X 1004 Calculated -
Log P
4.3
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known 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
Regulatory data - 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)
1.45
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)
0.25
B5 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here )
5 = Verified data used for regulatory purposes
Low volatility. If applied directly to plants, drift is a concern & mitigation is advisable
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
2.45 X 10-02
H4 H = The US ARS pesticide properties database. Dataset is no longer available.
4 = Verified data
Non-volatile
Volatilisation as max % of applied dose lost
From plant surface
- - -
From soil surface
- - -
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)
80
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Moderately persistent
DT₅₀ (lab at 20 °C)
45
DW4 DW = Don Wauchope personal database for Pka data: Wauchope, R. D. and Edwards, J. Dissociation constants for pesticide active ingredients: a database and comparison with predicted values. Dataset is no longer available.
4 = Verified data
Moderately persistent
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
Best available data DT₅₀ range 40-80 days
Dissipation rate RL₅₀ (days) on plant matrix
Value
3.7
R4 R = Peer reviewed scientific publications
4 = Verified data
-
Note
Published literature RL₅₀ range 1.7-5.9 days, 5 field & undercover grown crops, various matrices, n=6
Dissipation rate RL₅₀ (days) on and in plant matrix
Value
2.7
R4 R = Peer reviewed scientific publications
4 = Verified data
-
Note
Published literature RL₅₀ range 2.6-2.8 days, 36 field crops, various matrices, n=3
Aqueous photolysis DT₅₀ (days) at pH 7
Value
26
K3 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here )
3 = Unverified data of known source
Slow
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
3.3
K3 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here )
3 = Unverified data of known source
Non-persistent
Note
pH sensitive: DT₅₀ 85 days at pH 5, 26 minutes at pH 9 (L3)
Water-sediment DT₅₀ (days)
29
K2 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here )
2 = Unverified data of unknown source
Fast
Water phase only DT₅₀ (days)
- - -
Air degradation
As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.
Decay in stored produce DT₅₀
-
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd (mL g⁻¹)
-
H3 H = The US ARS pesticide properties database. Dataset is no longer available.
3 = Unverified data of known source
Non-mobile
Koc (mL g⁻¹)
6064
Notes and range
Other source: 6945 mL g⁻¹ sandy soil (H3); 5000 (G3)
Freundlich
Kf (mL g⁻¹)
- - -
Kfoc (mL g⁻¹)
-
1/n
-
Notes and range
-
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
0.36 Calculated Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
8.34 X 10-03 Calculated -
Note
-
Potential for particle bound transport index
High Calculated -
Potential for loss via drain flow
Non-mobile Calculated -
Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk
- - -
Bio-concentration factor
BCF (l kg⁻¹)
10000
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
Whole fish
High potential
CT₅₀ (days)
Not available -
Known soil metabolites
Metabolite
Major/Minor fraction
Estimated maximum occurrence fraction
Notes
2-chlorobenzoic acid (Ref: AE-C500233)
- - -
1-(2-chlorophenyl)-1-(4'-chlorophenyl)-2,2-dichloroethanol
- - Aerobic
o,p-dichlorobenzohydrol (Ref: o,p-DCBH)
- - Aerobic
3-hydroxy-2,4-dichlorobenzophenone (Ref: OH-DCBP)
- - Aerobic
3-hydroxy-4,4'-dichlorobenzophenone (Ref: 3-OH-DCBP)
- - Aerobic
1-(2-chlorophenyl)-1-(4'-chlorophenyl)-2,2-dichloroethanol (Ref: FW-152)
- - Aerobic
1,1-bis(4-chlorophenyl)-2,2-dichloroethanole
- - Anaerobic
2,4-dichlorobenzophenone
- - Photolysis
2,4-dichlorobenzhydrol
- - Aerobic
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)
578
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
Moderate
Mammals - Short term dietary NOEL
(mg kg⁻¹)
0.25
L2 L = Pesticide manuals and hard copy reference books / other sources
2 = Unverified data of unknown source
Rat 2 yr
High
(ppm diet)
5 -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
1418
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)
43.1
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Moderate
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)
19
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
Apis mellifera
Moderate
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
> 10
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
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)
Moderately harmful
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
Parasitic wasp
-
Beneficial insects (Predatory mites)
Harmful
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
Predatory mite
-
Beneficial insects (Ground beetles)
- - -
Aquatic ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
0.51
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Lepomis macrochirus
Moderate
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
0.0044
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Oncorhynchus mykiss
High
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
3.83
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
Danio rerio EC₅₀ Embryo
Moderate
Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
0.14
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Daphnia magna
Moderate
Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
125
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
Daphnia magna
Low
Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (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)
630
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
Chironomus dilutus Growth
Low
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
0.075
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Scenedesmus subspicatus
Moderate
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
0.05
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
Unknown species
Moderate
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)
578
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
2500
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rabbit
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
5.0
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
-
Other Mammal toxicity endpoints
- - -
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
0.002
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
-
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
0.15
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
-
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)
- - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)
None allocated
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
-
Dermal penetration studies (%)
- - -
Dangerous Substances Directive 76/464
List I; List II - -
Exposure Routes
Public
Low risk to Europeans as no longer approved for use
Occupational
Low risk to Europeans as no longer approved for use
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
- - -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
?Possibly, status not identified
A3 A = Chromosome aberration (EFSA database)
3 = Negative
;
B3 B = DNA damage/repair (EFSA database)
3 = Negative
;
C3 C = Gene mutation (EFSA database)
3 = Negative
;
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
No data found
XNo, known not to cause a problem
Yes, known to cause a problem
Respiratory tract irritant Skin irritant Skin sensitiser
Yes, known to cause a problem
Yes, known to cause a problem
?Possibly, status not identified
Eye irritant Phototoxicant  
Yes, known to cause a problem
No data found  
General human health issues
Harmful by inhalation, ingestion and through skin contact
IARC Group 3 carcinogen - not classifiable; US EPA - possible human carcinogen
Endocrine issues - Inhibition of androgen synthesis
Handling issues
Property
Value and interpretation
General
No information available
CLP classification 2013
Health: H302, H312, H315, H317
Environment: H400, H410
WHO Classification
II (Moderately hazardous)
UN Number
-
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
dicofol
French
dicofol
German
Dicofol
Danish
dicofol
Italian
dicofol
Spanish
dicofol
Greek
dicofol
Polish
dikofol
Swedish
-
Hungarian
-
Dutch
dicofol
Norwegian
-

Record last updated: 21/08/2024
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