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Difenzoquat metilsulfate (Ref: AC 84777)
(Also known as: difenzoquat methyl sulphate; difenzoquat methyl sulfate; CL84777; BAS 450H; difenzoquat metilsulphate)
SUMMARY
Difenzoquat metilsulfate is a herbicide mainly used to control wild oats. It is highly soluble in water and has a low volatility. It can be environmentally persistent depending on local conditions. It tends to be moderately toxic to biodiverrsity. Difenzoquat metilsulfate is moderately toxic to mammals vi the oral route.
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:
Persistent; Potential for particle bound transport: High
Ecotoxicity
Moderate alert:
Daphnia acute ecotoxicity: Moderate; Bees acute contact ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate
Human health
Moderate alert:
Mammals acute toxicity: Moderate
GENERAL INFORMATION
Description
A post-emergence quarternary ammonium herbicide for wild oat control
Example pests controlled
Wild oats; Powdery mildew
Example applications
Cereals including wheat, barley; Alfalfa; Maize; Clover seed crops
Efficacy & activity
-
Availability status
Current
Introduction & key dates
1982, 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
Not applicable
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
None
Chemical formula
C₁₈H₂₀N₂O₄S
Canonical SMILES
CN1C(=CC(=[N+]1C)C2=CC=CC=C2)C3=CC=CC=C3.COS(=O)(=O)[O-]
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
XQEMNBNCQVQXMO-UHFFFAOYSA-M
International Chemical Identifier (InChI)
InChI=1S/C17H17N2.CH4O4S/c1-18-16(14-9-5-3-6-10-14)13-17(19(18)2)15-11-7-4-8-12-15;1-5-6(2,3)4/h3-13H,1-2H3;1H3,(H,2,3,4)/q+1;/p-1
2D structure diagram/image available?
Yes
General status
Pesticide type
Herbicide, Fungicide
Substance groups
Phenylpyrazole herbicide; Quarternary ammonium compound; Pyrazole herbicide
Minimum active substance purity
>96%
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Selective, absorbed by foliage. Acts via the rapid destruction of cell membranes.
CAS RN
43222-48-6
EC number
256-152-5
CIPAC number
367
US EPA chemical code
106401
PubChem CID
39424
CLP index number
No data found
Molecular mass
360.43
PIN (Preferred Identification Name)
1,2-dimethyl-3,5-diphenyl-1H-pyrazol-2-ium methyl sulfate
IUPAC name
1,2-dimethyl-3,5-diphenyl-1H-pyrazolium methyl sulfate
CAS name
1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate
Other status information
-
Relevant Environmental Water Quality Standards
-
Herbicide Resistance Classification (HRAC)
Z
Herbicide Resistance Classification (WSSA)
0
Insecticide Resistance Classification (IRAC)
Not applicable
Fungicide Resistance Classification (FRAC)
Not known
Examples of recorded resistance
-
Physical state
Colourless crystals
Related substances & organisms
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Amvac Chemical Corp
  • BASF
  • King Tech
  • American Cyanamid
Example products using this active
  • Finaven
  • Yeh-Yan-Ku
  • Avenge
Formulation and application details
Usually supplied as a water miscible liquid or soluble powder
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
765000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 High
Solubility - In organic solvents at 20 °C (mg l⁻¹)
360000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Dichloromethane		 -
500000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Chloroform		 -
558000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Methanol		 -
9800
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Acetone		 -
Melting point (°C)
157
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)
82
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
2.45 X 10-01 Calculated -
Log P
-0.61
T4 T = UN EPFA database. Dataset no longer available.
4 = Verified data
 Low
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
0.8
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 -
Dissociation constant pKa) at 25 °C
7
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 -
Weak acid
Vapour pressure at 20 °C (mPa)
0.01
H4 H = The US ARS pesticide properties database. Dataset is no longer available.
4 = Verified data
 Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
5.70 X 10-11
H4 H = The US ARS pesticide properties database. Dataset is no longer available.
4 = Verified data
 Non-volatile
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)
90
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 Moderately persistent
DT₅₀ (lab at 20 °C)
100
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
 Persistent
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
Other sources: DT₅₀ 3 months (R3)
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
Stable
W4 W = French database provided by ARVALIS-Institut du Végétal. Dataset no longer available.
4 = Verified data
 Stable
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
-
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 Non-mobile
Koc
30000
Notes and range
Other sources: Log Koc 4.49-5.80
Freundlich
Kf
166
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
(for difenzoquat)		 Non-mobile
Kfoc
9702
1/n
1.39
Notes and range
Kf range 29-664 mL g⁻¹; Kfoc range 1740-33200 mL g⁻¹; 1/n range 1.05-1.54; Soils=9
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
0.03 Calculated Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
5.31 X 10-03 Calculated -
Note
-
Potential for particle bound transport index
High Calculated -
Potential for loss via drain flow
Non-mobile Calculated -
Bio-concentration factor
BCF (l kg⁻¹)
20
P4 P = Other non-EU, UK or US Governments and Regulators
4 = Verified data
 Low potential
CT₅₀ (days)
Not available -
Known soil metabolites
Metabolite
Major/Minor fraction
Estimated maximum occurrence fraction
Notes
difenzoquat (Ref: BAS 450H)
Major fraction - -
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)
373
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)
-
L2 L = Pesticide manuals and hard copy reference books / other sources
2 = Unverified data of unknown source
Rat 2 year		 -
(ppm diet)
500 -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
> 4640
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Colinus virginianus		 Low
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
> 400
Q3 Q = Miscellaneous data from online 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)
36
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Apis mellifera		 Moderate
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 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
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
694
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Oncorhynchus mykiss		 Low
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
2.63
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
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)
0.54
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
- - -
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)
373
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)
3540
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rabbit		 -
Mammals - Inhalation LC₅₀ (mg l⁻¹)
0.36
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat 4 hr		 -
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)
- - -
Mammalian dose elimination route and rate
- - -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
XNo, known not to cause a problem
A3 A = Chromosome aberration (EFSA database)
3 = Negative
;
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
XNo, known not to cause a problem
XNo, known not to cause a problem
XNo, known not to cause a problem
Respiratory tract irritant Skin irritant Skin sensitiser
No data found
XNo, known not to cause a problem
 No data found
Eye irritant Phototoxicant  
✓Yes, known to cause a problem
 No data found  
General human health issues
Moderately toxic
May cause irreversible eye damage
Handling issues
Property
Value and interpretation
General
Hygroscopic
IMDG Transport Hazard Class 6.1
CLP classification 2013
Health: H302
Environment: H400, H410
WHO Classification
II (Moderately hazardous)
UN Number
UN2811
Waste disposal & packaging
Packaging Group II (moderate danger)
Shelf-life, storage, stability and reactivity
-
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