Dichlorophen	Last updated: 15/01/2023
(Also known as: antiphen; anthifen)

---

SUMMARY

Dichlorophen is a fungicide, herbicide, bactericide and algicide. It has a low 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.

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: Potential for particle bound transport: Medium Warning: Significant data are missing	Ecotoxicity Moderate alert: Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate Warning: Significant data are missing	Human health Moderate alert: Possible Carcinogen; Possible Reproduction/development effects

GENERAL INFORMATION

Description	Used to control some tapeworms in domestic pets including Taenia spp and Dipylidium spp but not Echinococcus spp
Availability status	-
Introduction & key dates	First patented 1944 USA
Examples of species treated	Dogs, Cats

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
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
ATCvet Code	QP52AG01
Therapeutic Class	Antiparasitic products, insecticides & repellents: Anthelmintics
Controlled Drug?	No
Regulation 37/2010 MRL Classification	No data
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	UK Legal Class
Example products using this active	Dichlorophen Tablets BP	Battle Haywood & Bower Ltd	UK National authorisation	Authorised veterinary medicine for general sale (AVM - GSL)
	Johnsons Easy Tapewormer for cats	Johnsons Veterinary Products Ptd	UK National authorisation	Authorised veterinary medicine for general sale (AVM - GSL)
	Johnsons twin wormer for cats	Johnsons Veterinary Products Ptd	UK National authorisation	Authorised veterinary medicine for general sale (AVM - GSL)
	Wilko Dual Action Worming Tablets For Cats	Armitage Pet Products Ltd	UK National authorisation (IC)	Authorised veterinary medicine for general sale (AVM - GSL)
Formulation and application details	Usually supplied as an emulsifiable concentrate from crop protection purposes. As an animal insecticide formulations include cutaneous sprays, tablets for oral administration and shampoos

ENVIRONMENTAL FATE

Property		Value	Source; quality score; and other information	Interpretation
Solubility - In water at 20 °C (mg l⁻¹)		30	C4 C = AGRITOX (click here ) 4 = Verified data	Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)		800000	C4 C = AGRITOX (click here ) 4 = Verified data Acetone	-
		530000	C4 C = AGRITOX (click here ) 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 (click here ) 4 = Verified data	High
Fat solubility of residues	Solubility	-	-	-
	Data type	-	-	-
Density (g ml⁻¹)		1.42	Q2 Q = Miscellaneous internet resources 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
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)	13	Q2 Q = Miscellaneous internet resources 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)		-	-	-

Soil adsorption and mobility

Property		Value	Source; quality score; and other information	Interpretation
Linear	Kd	-	Q2 Q = Miscellaneous internet resources 2 = Unverified data of unknown source	Non-mobile
	Koc	4103
	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		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	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)	-	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	-	-	-
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	-
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)		0.54	F2 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment ) 2 = Unverified data of unknown source Oncorhynchus mykiss 48 hour	Moderate
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 (US EPA Databases Related to Pesticide Risk Assessment ) 4 = Verified data Pimephales promelas	Moderate
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		6.2	C4 C = AGRITOX (click here ) 4 = Verified data Daphnia magna	Moderate
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)		10	F1 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (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	-	-	-

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	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)		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 / IPCS INCHEM (ChemID; IPCS INCHEM ) 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 ?Possibly, status not identified 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	III (Slightly hazardous)
UN Number	-
Waste disposal & packaging	-

TRANSLATIONS

Language	Name
English	dichlorophen
French	dichlorophene
German	Dichlorophen
Danish	dichlorophen
Italian	diclorofene
Spanish	diclorofen
Greek	dichlorophen
Polish	dichlorofen
Swedish	-
Hungarian	-
Dutch	dichlorofeen

---

Record last updated:	15/01/2023
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