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Dichlone (Ref: USR 604)
Last updated: 17/08/2021
(Also known as: dichloronaphthoquinone; sanquinon)
SUMMARY
Dichlone is an obsolete foliar fungicide. It has a low aqueous solubility and is not mobile and, based on its chemical properties, it is unlikely to leach to groundwater. It is not persistent in most soil systems. Dichlone has a moderate mammalian toxicity. Little has been reported regarding its toxicity to biodiversity.
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
High alert:
Daphnia acute ecotoxicity: High
Warning:
Significant data are missing
Human health
Moderate alert:
Mammals acute toxicity: Moderate
GENERAL INFORMATION
Description
Used to control fungal pathogens on tree fruit. Also used to control blue algae in ponds.
Example pests controlled
Brown rot; Scab; Blossom blight; Algae
Example applications
Apples; Pears; Plums; Cherries; Aquatic situations
Efficacy & activity
-
Availability status
Considered obsolete but may be available in some countries
Introduction & key dates
1943, first reported
UK regulatory status
UK COPR regulatory status
Not approved
Date COPR inclusion expires
Not applicable
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
Not applicable
Date EC 1107/2009 inclusion expires
Not applicable
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
                 
Additional information
Also used in
-
Chemical structure
Isomerism
-
Chemical formula
C₁₀H₄Cl₂O₂
Canonical SMILES
C1=CC=C2C(=C1)C(=O)C(=C(C2=O)Cl)Cl
Isomeric SMILES
No data
International Chemical Identifier key (InChIKey)
SVPKNMBRVBMTLB-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C10H4Cl2O2/c11-7-8(12)10(14)6-4-2-1-3-5(6)9(7)13/h1-4H
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
dichlone -
General status
Pesticide type
Fungicide, Algicide
Substance group
Quinone
Minimum active substance purity
>95%
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Foliar with protective action
CAS RN
117-80-6
EC number
204-210-5
CIPAC number
149
US EPA chemical code
029601
PubChem CID
8342
Molecular mass
227.04
PIN (Preferred Identification Name)
2,3-dichloronaphthalene-1,4-dione
IUPAC name
2,3-dichloro-1,4-naphthoquinone
CAS name
2,3-dichloro-1,4-naphthalenedione
Other status information
-
Relevant Environmental Water Quality Standards
-
Herbicide Resistance Classification (HRAC)
Not applicable
Herbicide Resistance Classification (WSSA)
Not applicable
Insecticide Resistance Classification (IRAC)
Not applicable
Fungicide Resistance Classification (FRAC)
Not known
Examples of recorded resistance
-
Physical state
-
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Uniroyal Chemical Co.
  • FMC: Hopkins Agriculture
Example products using this active
  • Kolo
  • Phygon
  • Quintar
Formulation and application details
Usually supplied as a wettable powder
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
0.1
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
at 25 °C		 Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)
50000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Acetone		 -
50000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Ethyl acetate		 -
50000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Acetic acid		 -
Melting point (°C)
195
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Submlines >32 °C		 -
Boiling point (°C)
275
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
4.17 X 1005 Calculated -
Log P
5.62
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 High
Bulk density (g ml⁻¹)
1.54
Q2 Q = Miscellaneous internet resources
2 = Unverified data of unknown source
 -
Dissociation constant pKa) at 25 °C
- - -
-
Vapour pressure at 20 °C (mPa)
0.01
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)
- - -
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)
10
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
 Non-persistent
DT₅₀ (lab at 20 °C)
- - -
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
-
Dissipation rate RL₅₀ on plant matrix
Value
- - -
Note
-
Dissipation rate RL₅₀ on and in plant matrix
Value
- - -
Note
-
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
-
US3 US = US Dept of Agriculture National Resources Conservation Service - various datasheets, databases and online sources
3 = Unverified data of known source
 Non-mobile
Koc
10000
Notes and range
-
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
0.00 Calculated Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
5.35 X 10-03 Calculated -
Note
Estimated concentrations of chemicals with Koc values greater than 9995 ml g⁻¹ are beyond the scope of the regression data used in SCI-GROW development. If there are concerns for such chemicals, a higher tier groundwater exposure assessment should be considered, regardless of the concentration returned by SCI-GROW
Potential for particle bound transport index
Medium Calculated -
Potential for loss via drain flow
Non-mobile Calculated -
ECOTOXICOLOGY
Property
Value
Source; quality score; and other information
Interpretation
Bio-concentration factor
BCF (l kg⁻¹)
Low risk
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
Based on LogP < 3		 Low risk
CT₅₀ (days)
- -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 1300
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)
- - -
(ppm diet)
- -
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)
- - -
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
0.31
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Salmo trutta		 Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
0.014
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)
- - -
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)
- - -
Non-target plants
- - -
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
- - -
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
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)
Non-toxic
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 Non-toxic
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
-
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
- - -
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
- - -
Other soil macro-organisms
Acute LC₅₀ (mg kg⁻¹)
- - -
Chronic NOEC (mg kg⁻¹)
- - -
Other arthropod (1)
LR₅₀ g ha⁻¹
- - -
% Effect
- - -
Other arthropod (2)
LR₅₀ g ha⁻¹
- - -
% Effect
- - -
Soil micro-organisms
- - -
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)
> 1300
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)
5000
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)
- - -
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
-
Occupational
-
MRLs
European
EU MRL pesticide database 
Great Britain
GB MRL Register 
Notes
-
Drinking Water Standards
- - -
Drinking Water MAC (μg l⁻¹)
- - -
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
 No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
No data found
XNo, known not to cause a problem
XNo, known not 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
Harmful if swallowed
Handling issues
Property
Value and interpretation
General
No information available
CLP classification 2013
Health: H302, H315, H319
Environment: H400, H410
EC Risk Classification
Xn - Harmful: R22
Xi - Irritant: R36, R38
N - Dangerous for the environment: R50, R53
EC Safety Classification
S2, S26, S60, S61
WHO Classification
NL (Not listed)
UN Number
-
Waste disposal & packaging
-
TRANSLATIONS
Language
Name
English
dichlone
French
dichlone
German
Dichlon
Danish
-
Italian
-
Spanish
diclona
Greek
-
Polish
dichlon
Swedish
-
Hungarian
-
Dutch
-
Record last updated: 17/08/2021
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