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Dichlorophen
Last updated: 23/01/2025
(Also known as: antiphen; anthifen)
SUMMARY
Dichlorophen is a fungicide, herbicide, bactericide and algicide. It has a moderate aqueous solubility and, based on its chemical properties, it is unlikely to leach to groundwater. It is not usually persistent in soils. Dichlorophen has a low mammalian toxicity but is moderately toxic to fish, aquatic invertebrates and algae.
GENERAL INFORMATION
Description
A phenolic, antihelminthic veterinary drug
Availability status
Current
Introduction & key dates
1944, first patented USA
Examples of veterinary uses
Used to control some tapeworms including Taenia spp. and Dipylidium spp. but not Echinococcus spp.
Examples of species treated
Dogs; Cats
Approval status
VMR 2013/2033 approval status (GB/UK)
Approved
EU Regulatory approval status
Approved
Chemical structure
Isomerism
None
Chemical formula
C₁₃H₁₀Cl₂O₂
Canonical SMILES
C1=CC(=C(C=C1Cl)CC2=C(C=CC(=C2)Cl)O)O
Isomeric SMILES
Clc1cc(c(O)cc1)Cc2cc(Cl)ccc2O
International Chemical Identifier key (InChIKey)
MDNWOSOZYLHTCG-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C13H10Cl2O2/c14-10-1-3-12(16)8(6-10)5-9-7-11(15)2-4-13(9)17/h1-4,6-7,16-17H,5H2
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
dichlorophen -
General status
Veterinary substance type
Antiparasitic, Antimicrobial, Anthelmintic
Other bioactivity & uses
Bactericide; Biocide; Preservative; Slimicide; Disinfectant; Algicide
Substance groups
Bridged diphenyl fungicide; Phenolic compound
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Contact
Molecular targets
-
CAS RN
97-23-4
EC number
202-567-1
CIPAC number
325
US EPA chemical code
055001
PubChem CID
3037
CLP index number
604-019-00-0
Therapeutic Class
Antiparasitic products, insecticides & repellents: Anthelmintics
ATCvet Code
QP52AG01
Controlled Drug?
No
Regulation 37/2010 MRL Classification
-
Molecular mass
269.1
PIN (Preferred Identification Name)
2,2'-methylenebis(4-chlorophenol)
IUPAC name
4,4'-dichloro-2,2'-methylenediphenol
CAS name
2,2'-methylenebis[4-chlorophenol]
Other status information
-
Relevant Environmental Water Quality Standards
-
Physical state
Colourless crystals
Formulations
Property
Product
Manufacturer
Authorisation Route
Legal Class (GB/UK)
Example products (past and present) using this active
Beaphar Multiwormer Beaphar UK Ltd UK National authorisation Authorised veterinary medicine for general sale (AVM-GSL)
Formulation and application details
Usually supplied in tablet form
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
30
C4 C = AGRITOX dataset. Dataset is no longer available.
4 = Verified data
 Moderate
Solubility - In organic solvents at 20 °C (mg l⁻¹)
800000
C4 C = AGRITOX dataset. Dataset is no longer available.
4 = Verified data
Acetone		 -
530000
C4 C = AGRITOX dataset. Dataset is no longer available.
4 = Verified data
Ethanol		 -
540000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Isopropanol		 -
Melting point (°C)
177.5
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 -
Boiling point (°C)
- - -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
1.70 X 1003 Calculated -
Log P
3.23
C4 C = AGRITOX dataset. Dataset is no longer available.
4 = Verified data
 High
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
1.42
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
 -
Dissociation constant pKa) at 25 °C
7.6
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 -
pKa(2) 11.6, Weak acid
Vapour pressure at 20 °C (mPa)
1.30 X 10-05
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)
1.17 X 10-07
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 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)
- - -
Refractive Index
- - -
Environmental release
-
Degradation
Property
Value
Source; quality score; and other information
Interpretation
Soil degradation (days) (aerobic)
DT₅₀ (typical)
13
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
 Non-persistent
DT₅₀ (lab at 20 °C)
- - -
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)
- - -
Sediment 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)
-
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
 Non-mobile
Koc (mL g⁻¹)
4103
Notes and range
Estimated
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
0.43 Calculated Low leachability
Bio-concentration factor
BCF (l kg⁻¹)
45.4
J4 J = Pesticide Action Network database (click here )
4 = Verified data
 Low potential
CT₅₀ (days)
Not available -
Known metabolites

None

ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
2690
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
Rat		 Low
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)
2000 -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
- - -
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)
- - -
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)
- - -
Chronic
- - -
Notes
-
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
Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
0.54
F2 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 )
2 = Unverified data of unknown source
Oncorhynchus mykiss 48 hr		 Moderate
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
> 0.154
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
Pimephales promelas		 Moderate
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
6.2
C4 C = AGRITOX dataset. Dataset is no longer available.
4 = Verified data
Daphnia magna		 Moderate
Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
- - -
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)
- - -
Aquatic plants (free-floating, growth) - Acute 7 day EC₅₀, biomass (mg l⁻¹)
- - -
Aquatic plants (rooted, growth) - Acute 14 day EC₅₀, biomass (mg l⁻¹)
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
10
F1 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 )
1 = Estimated data with little or no verification
Unknown species		 Moderate
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
Mesocosm study data
NOEAEC mg l⁻¹
- - -
NOEAEC mg l⁻¹
- - -
Marine bivalves
- - -
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)
2690
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
Rat		 Low
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
1000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Mouse		 -
Mammals - Inhalation LC₅₀ (mg l⁻¹)
- - -
Other Mammal toxicity endpoints
Intravenous DT₅₀ = 17.0 mg kg⁻¹
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Rat		 -
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
Low risk to Europeans as no longer approved for use
Occupational
Low risk to Europeans as no longer approved for use
Mammalian dose elimination route and rate
Well absorbed and metabolised by the liver, excreted mainly in the faeces
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
 -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
XNo, known not to cause a problem
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
?Possibly, status not identified
XNo, known not to cause a problem
 No data found
Respiratory tract irritant Skin irritant Skin sensitiser
No data found
✓Yes, known to cause a problem
XNo, known not to cause a problem
Eye irritant Phototoxicant  
✓Yes, known to cause a problem
✓Yes, known to cause a problem
  
General human health issues
Moderately toxic
Handling issues
Property
Value and interpretation
General
No information available
CLP classification 2013
Health: H302, H319
Environment: H400, H410
WHO Classification
II (Moderately hazardous)
UN Number
-
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
dichlorophen
French
dichlorophene
German
Dichlorophen
Danish
dichlorophen
Italian
diclorofene
Spanish
diclorofen
Greek
dichlorophen
Polish
dichlorofen
Swedish
-
Hungarian
-
Dutch
dichlorofeen
Norwegian
-
Record last updated: 23/01/2025
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