Bromacil is a soil acting uracil herbicide which is is used to control both annual and perennial weeds, although some essential uses may be authorised. It is moderately soluble in water and highly soluble in many organic solvents. It is not considered volatile. It may be persistent in soil and water systems depending on local conditions. Theres is also concerns regarding its potential to leach to groundwater. It tends to demonstrate a low to moderate toxicity to most fauna and flora. It has a moderate mammalian oral toxicity and no other serious human health concerns have been identified.
Hazard 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. These hazard alerts do not take account of usage patterns or exposure, thus do not represent risk.
Environmental fate
Ecotoxicity
Human health
Environmental fate High alert: GUS: High leachability; Drainflow: Mobile
Warning: Significant data are missing
Ecotoxicity Moderate alert: Fish acute ecotoxicity: Moderate
Human health Moderate alert: Mammals acute toxicity: Moderate; Possible Carcinogen; Endocrine disrupter
GENERAL INFORMATION
Description
A soil acting uracil herbicide used to control a wide variety of annual and perennial weeds mainly on non-crop areas and fruit
Fruit including citrus, pineapples; Brush; Roads, rights-of-way, railways, pavements
Efficacy & activity
-
GB regulatory status
GB COPR regulatory status
Not approved
Date COPR inclusion expires
Expired
GB LERAP status
No UK approval for use as a plant protection agent
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
Australia; USA
Chemical structure
Isomerism
Bromacil exhibits stereoisomerism due to the presence of a chiral centre in its sec-butyl side chain attached to the uracil ring. This chirality allows for the existence of two enantiomers. Although bromacil is typically used as a racemic mixture, each enantiomer may interact differently with biological systems, potentially influencing herbicidal activity and environmental behaviour. The stereochemistry of bromacil is especially relevant in its role as a photosystem II inhibitor, where subtle differences in molecular orientation can affect binding affinity and efficacy.
Example manufacturers & suppliers of products using this active now or historically
Nufarm
DuPont
Loveland
Makhteshim-Agan
Example products using this active
Hyvar X bromacil
Borocil 1V
Cynogan
Borea
Krovar II
Urgan
Formulation and application details
Available in a variety of formulations including wettable powders, water soluble liquids and granules.
Commercial production
Bromacil is synthesised through a multi-step chemical process beginning with sec-butylamine, which reacts with solid phosgene to form an isocyanate ester. This intermediate is then combined with methyl 3-aminocrotonate in the presence of sodium methoxide, catalysing the formation of a uracil ring structure. The final step involves bromination at the 5-position of the uracil ring using elemental bromine in a polar solvent, yielding 5-bromo-3-sec-butyl-6-methyluracil, the active compound in bromacil herbicide. Improved methods have replaced phosgene with 2-bromobutane and used sodium hydride for cyclization, along with a Pyr-HBr-Br₂ complex for selective bromination, enhancing yield and reducing environmental hazards.
Impact on climate of production and use
Data for the amount of life cycle GHGs produced by bromacil are not available in the public domain. However, whilst estimates vary, more general data suggests that between 18 and 27 kilograms of CO₂e is emitted per kilogram of herbicide produced.
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
815
G4 G = Extension Toxicology network database EXTOXNET. Available online but no longer updated. (click here ) 4 = Verified data
Moderate
Solubility - In organic solvents at 20 °C (mg l⁻¹)
167000
C4 C = AGRITOX dataset. Dataset is no longer available. 4 = Verified data
Acetone
-
134000
C4 C = AGRITOX dataset. Dataset is no longer available. 4 = Verified data
Ethanol
-
32000
C4 C = AGRITOX dataset. Dataset is no longer available. 4 = Verified data
Xylene
-
Melting point (°C)
158.5
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
-
Boiling point (°C)
Decomposes before boiling
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
-
Degradation point (°C)
158
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
-
Flashpoint (°C)
-
-
-
Octanol-water partition coefficient at pH 7, 20 °C
P
7.59 X 1001
Calculated
-
Log P
1.88
H4 H = The US ARS pesticide properties database. Dataset is no longer available. 4 = Verified data
Low
Fat solubility of residues
Solubility
-
-
-
Data type
-
-
-
Density (g ml⁻¹)
1.59
L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source
-
Dissociation constant pKa) at 25 °C
9.27
H4 H = The US ARS pesticide properties database. Dataset is no longer available. 4 = Verified data
-
Very weak acid
Vapour pressure at 20 °C (mPa)
4.10 X 10-02
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)
1.50 X 10-05
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)
60
R4 R = Peer reviewed scientific publications 4 = Verified data
Moderately persistent
DT₅₀ (lab at 20 °C)
-
-
-
DT₅₀ (field)
-
-
-
DT₉₀ (lab at 20 °C)
-
-
-
DT₉₀ (field)
-
-
-
DT₅₀ modelling endpoint
-
-
-
Note
Other sources: DT₅₀ 5-6 months in silt loam soil (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
Stable
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 3 = Unverified data of known source
Stable
Note
Stable at pH 5 and pH 7
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
Stable
R4 R = Peer reviewed scientific publications 4 = Verified data
Stable
Note
Stable at all relevant pHs
Water-sediment DT₅₀ (days)
-
-
-
Water phase only DT₅₀ (days)
-
-
-
Sediment 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)
-
G3 G = Extension Toxicology network database EXTOXNET. Available online but no longer updated. (click here ) 3 = Unverified data of known source
Mobile
Koc (mL g⁻¹)
32
Notes and range
Other sources: log Koc 1.51 (Q3); General literature: Koc 2.3 to 289 (CA3)
Freundlich
Kf (mL g⁻¹)
2.9
R4 R = Peer reviewed scientific publications 4 = Verified data
Moderately mobile
Kfoc (mL g⁻¹)
117
1/n
0.917
Notes and range
Data for freshwater sediments Kf range 0.56-6.35 mL.g, Kfoc range 26.3-289 mL g⁻¹, 1/n range 0.89-0.98, Soils = 9
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
3.44
Calculated
High leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
5.51 X 10-01
Calculated
-
Note
-
Potential for particle bound transport index
Medium
Calculated
-
Potential for loss via drain flow
Mobile
Calculated
-
Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk
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
G3 G = Extension Toxicology network database EXTOXNET. Available online but no longer updated. (click here ) 3 = Unverified data of known source
-
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
?Possibly, status not identified
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
;
E3 E = Unspecified genotoxicity type (miscellaneous data source) 3 = Negative
?Possibly, status not identified
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
?Possibly, status not identified
✓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
May cause inflammation of the stomach and intestinal mucous membranes, gastroenteritis or liver damage IARC - Group C possible carcinogen; US EPA - possible human carcinogen
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
Environmental fate
Warning:
Ecotoxicity
