Terbuthylazine

Terbuthylazine	Last updated: 09/05/2025
(Also known as: bellacide)

SUMMARY

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: GUS: Transition state; Drainflow: Moderately mobile	Ecotoxicity Moderate alert: Birds acute ecotoxicity: Moderate; Birds chronic ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Daphnia chronic ecotoxicity: Moderate; Bees acute contact ecotoxicity: Moderate; Bees acute oral ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate	Human health High alert: Mammals chronic toxicity: High Warning: Significant data are missing

GENERAL INFORMATION

Description

A herbicide to control grass and broadleaved weeds in a variety of situations including forestry and for control slime-forming algae, fungi, and bacteria in non-agricultural situations

Example pests controlled

Pigwed; Goosefoot; Bladder weed; Dwarf marigold; Blackjack; Starbur; Evening primrose

Example applications

Maize; Sorghum; Apples; Citrus; Bush vines; Non-crop sites including roads, railways, industrial sites

Efficacy & activity

Availability status

Current

Introduction & key dates

1967, introduced; 2025, withdrawn UK

GB regulatory status

GB COPR regulatory status

Not approved

Date COPR inclusion expires

Not applicable

GB LERAP status

No data

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Spain/Hungary

Date EC 1107/2009 inclusion expires

31/05/2027

EU Candidate for substitution (CfS)

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; New Zealand; Morocco

Chemical structure

Isomerism

None

Chemical formula

C₉H₁₆ClN₅

Canonical SMILES

CCNC1=NC(=NC(=N1)Cl)NC(C)(C)C

Isomeric SMILES

International Chemical Identifier key (InChIKey)

FZXISNSWEXTPMF-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C9H16ClN5/c1-5-11-7-12-6(10)13-8(14-7)15-9(2,3)4/h5H2,1-4H3,(H2,11,12,13,14,15)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
terbuthylazine	-

General status

Pesticide type

Herbicide; Other substance

Other bioactivity & uses

Microbiocide; Algicide; Slimicide; Disinfectant

Substance groups

Triazine herbicide; Methoxytriazine herbicide

Minimum active substance purity

930 g kg⁻¹, typically 960-980 g kg⁻¹

Known relevant impurities

EU 2017 dossier - propazine, atrazine, simazine

Substance origin

Synthetic

Mode of action

Broad-spectrum with strong and rapid effects. Inhibits photosynthesis (photosystem II).

CAS RN

5915-41-3

EC number

227-637-9

CIPAC number

234

US EPA chemical code

080814

PubChem CID

22206

CLP index number

613-323-00-2

Molecular mass

229.71

PIN (Preferred Identification Name)

N2-tert-butyl-6-chloro-N4-ethyl-1,3,5-triazine-2,4-diamine

IUPAC name

N2-tert-butyl-6-chloro-N4-ethyl-1,3,5-triazine-2,4-diamine

CAS name

6-chloro-N-(1,1-dimethylethyl)-N'-ethyl-1,3,5-triazine-2,4-diamine

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Herbicide Resistance Class (WSSA MoA class)

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Not applicable

Examples of recorded resistance

Physical state

White crystalline powder

Formulations

Property

Value

Example manufacturers & suppliers of products using this active now or historically

Makhteshim
Orion Crop Protection Ltd
Sipcam
Syngenta

Example products using this active

Calaris
Skirmish
Gardo Gold

Formulation and application details

Usually supplied as a suspension concentrate or suspended emulsion formulation

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

6.6

Low

Solubility - In organic solvents at 20 °C (mg l⁻¹)

41000

Acetone

9800

Toluene

12000

n-Octanol

410

n-Hexane

Melting point (°C)

175

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

224

Flashpoint (°C)

Octanol-water partition coefficient at pH 7, 20 °C

2.51 X 10⁰³

Calculated

Log P

3.4

High

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data - observed in metabolism and farm animal feeding studies

Density (g ml⁻¹)

1.19

Dissociation constant pKa) at 25 °C

1.9

Vapour pressure at 20 °C (mPa)

0.152

Low volatility. If applied directly to plants, drift is a concern & mitigation is advisable

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

2.3 X 10^-03

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

Neutral solution: 222nm = 385386, 263nm = 3444
Acidic solution: 223nm = 30103, 263nm=4468
Basic solution, 223nm = 37426, 263nm = 3395

Surface tension (mN m⁻¹)

71.8

at 20°C 90% soln

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Not readily biodegradable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

72.0

Moderately persistent

DT₅₀ (lab at 20 °C)

72.0

Moderately persistent

DT₅₀ (field)

21.8

Non-persistent

DT₉₀ (lab at 20 °C)

353

Persistent

DT₉₀ (field)

72.6

DT₅₀ modelling endpoint

Note

EU 2017 dossier lab studies DT₅₀ range 38.2-167 days, Soils = 12, Field studies DT₅₀ range 6.43-149 days, DT₉₀ range 1,6-497 days, Soils = 23; EU dossier 2007 lab studies DT₉₀ range 196-837 days; field studies DT₅₀ range 10.0-35.8 days, DT₉₀ range 33.3-119 days

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

Note

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

Stable

Note

pH variable: stable at pH 7 and pH 9, 73 days at pH 5, 50 °C

Water-sediment DT₅₀ (days)

Moderately fast

Water phase only DT₅₀ (days)

Moderately fast

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

K_d (mL g⁻¹)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

5.1

Moderately mobile

K_foc (mL g⁻¹)

231

¹/_n

0.93

Notes and range

EU dossier K_f range 2.1-10.49 mL g⁻¹, K_foc range 151-333 mL g⁻¹, ¹/_n range 0.88-0.98, Soils=9

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.19

Calculated

Transition state

SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate

Value

8.43 X 10^-02

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)

Whole fish

Low potential

CT₅₀ (days)

0.8

Known soil metabolites

Metabolite

Major/Minor fraction

$Click here for further information on Major/Minor fraction$

Estimated maximum occurrence fraction

Notes

desethyl-terbuthylazine (Ref: GS26379)

Major fraction

0.329

Syngenta verified

2-hydroxy-terbuthylazine (Ref: GS 23158)

Major fraction

0.345

Syngenta verified

2-hydroxy-desethyl-terbuthylazine (Ref: GS 28620)

Major fraction

0.119

Syngenta verified

Known groundwater metabolites

Metabolite

EC SANCO/221/2000 relevancy

ADI (mg kg⁻¹ bodyweight day⁻¹)

WHO drinking water guidance value (μg L⁻¹ day⁻¹)

desethyl-terbuthylazine (Ref: GS26379)

Relevant

2-hydroxy-terbuthylazine (Ref: GS 23158)

Not relevant

6-amino-[1,3,5]triazine-2,4-diol (ammelide)

Not relevant

2-[(4-amino-6-hydroxy-1,3,5-triazin-2-yl)amino]-2-methyl-propanoic acid

Not relevant

2,6-dihydroxy-7,7-dimethyl-6,8-dihydroimidazo[1,2-a][1,3,5]triazin-4-one

Not relevant

2-[[4-(ethylamino)-6-hydroxy-1,3,5-triazin-2-yl]amino]-2-methyl-propanoic acid

Not relevant

6-tert-butylamino-[1,3,5]triazine-2,4-diol

Not relevant

4-(tert-butyl amino)-6-hydroxy-1-methyl-1,3,5-triazin-2-one

Not relevant

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

terbutryn (Ref: GS 14260)

MT26

Sediment

de-t-butyl-hydroxy terbuthylazine

MT19

diamino-chlorotriazine

MT20

Plant

de-t-butyl-terbuthylazine

MT22

amino-dihydroxy triazine

MT24

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 1000

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

> 0.22

Rat 2 yr

High

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

4.5

Unknown species Reproductive NOAEL

High

Birds - Acute LD₅₀ (mg kg⁻¹)

> 1236

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

> 395 mg kg bw⁻¹ day⁻¹

Anas platyrhynchos

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

13.84

Coturnix japonica NOEL

Moderate

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

> 141.7

Eisenia foetida corr

Moderate

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)

Soil micro-organisms

Nitrogen mineralisation: No significant adverse effect
Carbon mineralisation: No significant adverse effect

Dose: 10.9 mg kg⁻¹ soil

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

321

Lettuce
Pre-emergence, EC₅₀
as mL product ha⁻¹ (Gardoprim Plus Gold containing 187.5 g l⁻¹ terbuthylazine)

439

Lettuce
Post-emergence, EC₅₀
as mL product ha⁻¹ (Gardoprim Plus Gold containing 187.5 g l⁻¹ terbuthylazine)

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 32

Apis mellifera

Moderate

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 22.6

Apis mellifera

Moderate

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Chronic

Notes

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) as Mortality LR₅₀ g ha⁻¹

> 750

Aphidius rhopalosiphi

Beneficial insects (Predatory mites) as Mortality LR₅₀ g ha⁻¹

> 750

Typhlodromus pyri

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

2.2

Oncorhynchus mykiss

Moderate

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

0.09

Oncorhynchus mykiss

Moderate

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Danio rerio EC₅₀ Eggs

Moderate

Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

21.2

Daphnia magna

Moderate

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

0.019

Daphnia magna

Moderate

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

0.167

Americamysis bahia

Moderate

Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)

0.5

Chironomus riparius

Moderate

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

Aquatic plants (free-floating, growth) - Acute 7 day EC₅₀, biomass (mg l⁻¹)

0.0128

Lemna gibba

Moderate

Aquatic plants (rooted, growth) - Acute 14 day EC₅₀, biomass (mg l⁻¹)

0.055

Myriophyllum spicatum

Moderate

Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)

0.012

Pseudokirchneriella subcapitata

Moderate

Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves

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)

> 1000

Rat

Moderate

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 5.3

Rat 4 hr (nose only)

Other Mammal toxicity endpoints

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

0.004

Dog SF=100

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

0.008

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

None reported

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

0.0032

Dermal penetration studies (%)

0.1-2.5

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Acceptable for proposed uses

Occupational

Acceptable risk for authorised agricultural uses

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

Drinking Water Standards

Non-statutory WHO drinking water guideline 0.007 mg l⁻¹

UK EA QS database 2018

Drinking Water MAC (μg l⁻¹)

Mammalian dose elimination route and rate

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

No data found

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

No data found

General human health issues

Toxic, may be fatal if inhaled, swallowed or absorbed through skin
Health effects may be delayed
Weak skin sensitiser

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
IMDG Transport Hazard Class 6.1
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Health: H373, H302
Environment: H400, H410

WHO Classification

III (Slightly hazardous)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

terbuthylazine

French

terbuthylazine

German

Terbuthylazin

Danish

terbutylazin

Italian

terbutilazina

Spanish

terbutilazina

Greek

Polish

terbutylazyna

Swedish

Hungarian

terbuthylazine

Dutch

terbuthylazine

Norwegian

Record last updated:	09/05/2025
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