(Also known as: chlorimuron ethyl ester; HSDB 6850)
SUMMARY
Chlorimuron-ethyl is a post-emergence, foliar applied herbicide. It has a high aqueous solubility, is non-volatile and, based on its chemical properties, is mobile and can be expected to leach to groundwater. It can be moderately persistent in soil systems but will not usually persist in aquatic systems. It is generally susceptible to hydrolysis. It has a low mammalian toxicity and has a high potential to bioaccumulate. It is relatively non- toxic to most aquatic species, birds and earthworms but moderately toxic to honeybees.
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: GUS: High leachability
Example manufacturers & suppliers of products using this active now or historically
AgroCare
DuPont
Cheminova
FCC
United Phosphorus
Example products using this active
Darban
Twister
Classic
Pilarclas
Sponsor
Authority Broadleaf Herbicide
Formulation and application details
Usually supplied as a flowable dry powder and used as an aqueous spray post-emergence
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
1200
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)
70500
H3 H = The US ARS pesticide properties database. Dataset is no longer available. 3 = Unverified data of known source
Acetone
-
8150
H3 H = The US ARS pesticide properties database. Dataset is no longer available. 3 = Unverified data of known source
Benzene
-
60
H3 H = The US ARS pesticide properties database. Dataset is no longer available. 3 = Unverified data of known source
n-Hexane
-
2830
H3 H = The US ARS pesticide properties database. Dataset is no longer available. 3 = Unverified data of known source
Xylene
-
Melting point (°C)
181
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
1.29 X 1000
Calculated
-
Log P
0.11
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
Low
Fat solubility of residues
Solubility
-
-
-
Data type
-
-
-
Density (g ml⁻¹)
1.51
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
-
Dissociation constant pKa) at 25 °C
4.2
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
-
Weak acid
Vapour pressure at 20 °C (mPa)
4.9 X 10-07
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)
1.7 X 10-10
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
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)
40
F3 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 ) 3 = Unverified data of known source
Moderately persistent
DT₅₀ (lab at 20 °C)
-
-
-
DT₅₀ (field)
28
R4 R = Peer reviewed scientific publications 4 = Verified data
Non-persistent
DT₉₀ (lab at 20 °C)
-
-
-
DT₉₀ (field)
-
-
-
DT₅₀ modelling endpoint
-
-
-
Note
Literature studies give field DT₅₀ 14-42 days; Degradation takes longer at higher pH.
Dissipation rate RL₅₀ (days) on plant matrix
Value
4.7
R3 R = Peer reviewed scientific publications 3 = Unverified data of known source
-
Note
Wheat straw, n=1
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
21
L2 L = Pesticide manuals and hard copy reference books / other sources 2 = Unverified data of unknown source
Non-persistent
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)
-
R4 R = Peer reviewed scientific publications 4 = Verified data
Moderately mobile
Koc (mL g⁻¹)
106
Notes and range
-
Freundlich
Kf (mL g⁻¹)
-
-
-
Kfoc (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
2.86
Calculated
High leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
2.15 X 10-01
Calculated
-
Note
-
Potential for particle bound transport index
Low
Calculated
-
Potential for loss via drain flow
Moderately mobile
Calculated
-
Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk
-
-
-
Bio-concentration factor
BCF (l kg⁻¹)
Low risk
Q3 Q = Miscellaneous data from online 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