(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 biodiversity. Difenzoquat metilsulfate is also moderately toxic to mammals via 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
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
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)
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 (days) on plant matrix
Value
-
-
-
Note
-
Dissipation rate RL₅₀ (days) 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)
-
-
-
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)
-
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Non-mobile
Koc (mL g⁻¹)
30000
Notes and range
Other sources: Log Koc 4.49-5.80
Freundlich
Kf (mL g⁻¹)
166
R3 R = Peer reviewed scientific publications 3 = Unverified data of known source
(for difenzoquat)
Non-mobile
Kfoc (mL g⁻¹)
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
-
Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk
-
-
-
Bio-concentration factor
BCF (l kg⁻¹)
20
P4 P = Other non-EU, UK or US Governments and Regulators 4 = Verified data
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
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