2,3,6-TBA (Ref: HC 1281)	Last updated: 15/01/2023
(Also known as: trichlorobenzoic acid; trichlorobenzene; trichlorobenzyl chloride metabolite; T-2)

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SUMMARY

2,3,6-TBA is a post-emergence herbicide. It is highly soluble in water and most organic solvents. It is considered volatile. Little has been reported on its environmental persistence or mobility. It is moderately toxic to mammals and a recognised irritant. Based on its chemical properties it would not expected to bioaccumulate. There are gaps in knowledge regarding its toxicity to biodiversity however data has shown that it is moderately toxic to bids, fish and 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: Drainflow: Mobile Warning: Significant data are missing	Ecotoxicity Moderate alert: Birds acute ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate Warning: Significant data are missing	Human health Moderate alert: Mammals acute toxicity: Moderate Warning: Significant data are missing

GENERAL INFORMATION

Description	A post-emergence herbicide used to control annual and perennial broad-leaved weeds
Example pests controlled	Woody weeds including root suckers; Honeysuckle; hemlock; Canada thistle; Adler; Sycamore; Trumpet vine;
Example applications	Cereals including wheat, barley, oats, field corn; Grass seed crops; Non-crop areas including railroads, rights of way, utility areas
Efficacy & activity	-
Availability status	Current
Introduction & key dates	1952, first reported

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

Additional information

Also used in	-

Chemical structure

Isomerism	None
Chemical formula	C₇H₃Cl₃O₂
Canonical SMILES	C1=CC(=C(C(=C1Cl)C(=O)O)Cl)Cl
Isomeric SMILES	No data
International Chemical Identifier key (InChIKey)	XZIDTOHMJBOSOX-UHFFFAOYSA-N
International Chemical Identifier (InChI)	InChI=1S/C7H3Cl3O2/c8-3-1-2-4(9)6(10)5(3)7(11)12/h1-2H,(H,11,12)
2D structure diagram/image available?	Yes

General status

Pesticide type	Herbicide
Substance groups	Benzoic acid herbicide
Minimum active substance purity	>97%
Known relevant impurities	-
Substance origin	Synthetic
Mode of action	Systemic, absorbed by leaves and roots with auxin type action
CAS RN	50-31-7
EC number	200-026-4
CIPAC number	49
US EPA chemical code	-
PubChem CID	5759
CLP index number	607-152-00-2
Molecular mass	225.45
PIN (Preferred Identification Name)	-
IUPAC name	2,3,6-trichlorobenzoic acid
CAS name	2,3,6-trichlorobenzoic acid
Other status information	-
Relevant Environmental Water Quality Standards	-
Herbicide Resistance Classification (HRAC)	O
Herbicide Resistance Classification (WSSA)	4
Insecticide Resistance Classification (IRAC)	Not applicable
Fungicide Resistance Classification (FRAC)	Not applicable
Examples of recorded resistance	-
Physical state	Colourless crystals

Formulations

Property	Value
Example manufacturers & suppliers of products using this active now or historically	DuPont FBC Union Carbide
Example products using this active	Trysben Benzac
Formulation and application details	Usually formulated as an aqueous solution

ENVIRONMENTAL FATE

Property		Value	Source; quality score; and other information	Interpretation
Solubility - In water at 20 °C (mg l⁻¹)		7700	CA3 CA = Medical and toxicological databases and information systems e.g. TOXNET (click here ) 3 = Unverified data of known source	High
Solubility - In organic solvents at 20 °C (mg l⁻¹)		607000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Acetone	-
		238000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Benzene	-
		237000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Chloroform	-
		637000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Ethanol	-
Melting point (°C)		125	CA3 CA = Medical and toxicological databases and information systems e.g. TOXNET (click here ) 3 = Unverified data of known source	-
Boiling point (°C)		Decomposes on distillation	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	-
Degradation point (°C)		-	-	-
Flashpoint (°C)		-	-	-
Octanol-water partition coefficient at pH 7, 20 °C	P	5.13 X 1002	Calculated	-
	Log P	2.71	CA2 CA = Medical and toxicological databases and information systems e.g. TOXNET (click here ) 2 = Unverified data of unknown source	Moderate
Fat solubility of residues	Solubility	-	-	-
	Data type	-	-	-
Density (g ml⁻¹)		-	-	-
Dissociation constant pKa) at 25 °C		1.687	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. MS in preparation 4 = Verified data	-
		Strong acid
Vapour pressure at 20 °C (mPa)		73.32	Q2 Q = Miscellaneous internet resources 2 = Unverified data of unknown source	Highly volatile
Henry's law constant at 25 °C (Pa m³ mol⁻¹)		2.15 X 10-03	V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM ) 3 = Unverified data of known source	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)	-	-	-
	DT₅₀ (lab at 20 °C)	-	-	-
	DT₅₀ (field)	-	-	-
	DT₉₀ (lab at 20 °C)	-	-	-
	DT₉₀ (field)	-	-	-
	DT₅₀ modelling endpoint	-	-	-
	Note	-
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	Stable	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	Stable
	Note	-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7	Value	-	-	-
	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	-	CA2 CA = Medical and toxicological databases and information systems e.g. TOXNET (click here ) 2 = Unverified data of unknown source	Mobile
	Koc	65
	Notes and range	Estimated
Freundlich	Kf	-	-	-
	Kfoc	-
	1/n	-
	Notes and range	-
pH sensitivity		-

Fate indices

Property		Value	Source; quality score; and other information	Interpretation
GUS leaching potential index		-	-	-
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate	Value	Cannot be calculated	-	-
	Note	-
Potential for particle bound transport index		-	-	-
Potential for loss via drain flow		-	-	-
Bio-concentration factor	BCF (l kg⁻¹)	40	Q3 Q = Miscellaneous internet resources 3 = Unverified data of known source	Low potential
	CT₅₀ (days)	Not available		-

Known soil metabolites

Metabolite	Major/Minor fraction	Estimated maximum occurrence fraction	Notes
2,4,5-trichlorophenol	-	-	-

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)		> 1500	CA3 CA = Medical and toxicological databases and information systems e.g. TOXNET (click here ) 3 = Unverified data of known source Rat	Moderate
Mammals - Short term dietary NOEL	(mg kg⁻¹)	-	-	-
	(ppm diet)	-		-
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Birds - Acute LD₅₀ (mg kg⁻¹)		2000	F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment ) 4 = Verified data Anas platyrhynchos	Moderate
Birds - Short term dietary (LC₅₀/LD₅₀)		-	-	-
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)		-	-	-
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)	-	-	-
	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)	> 100	L2 L = Pesticide manuals and hard copy reference books / other sources 2 = Unverified data of unknown source	Low
	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 pollinators (1)	Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)	-	-	-
	Mode of exposure	-
Other pollinators (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)		8.5	F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment ) 3 = Unverified data of known source Pimephales promelas	Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)		-	-	-
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		-	-	-
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)		-	-	-
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)		> 1500	CA3 CA = Medical and toxicological databases and information systems e.g. TOXNET (click here ) 3 = Unverified data of known source Rat	Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)		600	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Rabbit	-
Mammals - Inhalation LC₅₀ (mg l⁻¹)		14.0	AC3 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here ) 3 = Unverified data of known source Rat	-
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	Potentially via inhalation or dermal contact
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 No data found A0 A = Chromosome aberration (EFSA database) 0 = No data ; 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 No data found XNo, known not to cause a problem No data found Respiratory tract irritant Skin irritant Skin sensitiser ✓Yes, known to cause a problem ✓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		Over exposure may cause nausea, salivation, tremor and depression

Handling issues

Property	Value and interpretation
General	Not compatible with fertilisers
CLP classification 2013	Health: H302 Environment: H411
WHO Classification	III (Slightly hazardous)
UN Number	-
Waste disposal & packaging	-

TRANSLATIONS

Language	Name
English	2,3,6-TBA
French	2,3,6-TBA
German	2,3,6-TBA
Danish	2,3,6-TBA
Italian	2,3,6-TBA
Spanish	2,3,6-TBA
Greek	2,3,6-TBA
Polish	2,3,6-TBA
Swedish	2,3,6-TBA
Hungarian	2,3,6-TBA
Dutch	2,3,6-TBA

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Record last updated:	15/01/2023
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