Dicofol (Ref: ENT 23648)

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 as a pesticide

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)

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

Low

Solubility - In organic solvents at 20 °C (mg l⁻¹)

2600000

Dichloromethane

2750000

Methanol

1350000

Xylene

400000

Acetone

Melting point (°C)

370.5

Boiling point (°C)

193

Degradation point (°C)

Flashpoint (°C)

193

(open cup)

Octanol-water partition coefficient at pH 7, 20 °C

2.00 X 10⁰⁴

Calculated

Log P

4.3

High

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data - observed in metabolism and farm animal feeding studies

Density (g ml⁻¹)

1.45

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

0.25

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

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)

Moderately persistent

DT₅₀ (lab at 20 °C)

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

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

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

Slow

Note

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

3.3

Non-persistent

Note

pH sensitive: DT₅₀ 85 days at pH 5, 26 minutes at pH 9 (L3)

Water-sediment DT₅₀ (days)

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

K_d (mL g⁻¹)

Non-mobile

K_oc (mL g⁻¹)

6064

Notes and range

Other source: 6945 mL g⁻¹ sandy soil (H3); 5000 (G3)

Freundlich

K_f (mL g⁻¹)

K_foc (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

Whole fish

High potential

CT₅₀ (days)

Not available

Known soil metabolites

Metabolite

Major/Minor fraction

$Click here for further information on Major/Minor fraction$

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

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

0.25

Rat 2 yr

High

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

Birds - Acute LD₅₀ (mg kg⁻¹)

1418

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

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)

Apis mellifera

Moderate

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 10

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

Parasitic wasp

Beneficial insects (Predatory mites)

Harmful

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

Lepomis macrochirus

Moderate

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

0.0044

Oncorhynchus mykiss

High

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

3.83

Danio rerio EC₅₀ Embryo

Moderate

Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

0.14

Daphnia magna

Moderate

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

125

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

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

Scenedesmus subspicatus

Moderate

Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)

0.05

Unknown species

Moderate

Mesocosm study data

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

Rat

Moderate

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

2500

Rabbit

Mammals - Inhalation LC₅₀ (mg l⁻¹)

5.0

Rat

Other Mammal toxicity endpoints

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

0.002

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

0.15

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

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

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

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