Endothal

Endothal	Last updated: 18/01/2021
(Also known as: endothall; endothal acid)

SUMMARY

Endothal is a herbicide that does not have regulatory approval for use in the EU. It is highly soluble in water and semi-volatile. Based on its chemical properties it is not expected to leach to groundwater. It is generally non-persistent in soils. Endothal is highly toxic to mammals but is not expected to bioaccumulate. It is a recognised irritant. It is moderately toxic to fish and aquatic organisms but is less toxic to birds.

GENERAL INFORMATION

Description

An unclassified herbicide, defoliant plant growth regulator and algicide used to control annual grasses, broad-leaved and aquatic weeds

Example pests controlled

Plankton; Pondweed; Coontail; Milfoil; Algae; Fathen; Chickweed

Example applications

Aquatic situations; Sugarbeet; Spinach; Turf; Alfalfa; Potatoes; Cotton

Efficacy & activity

Availability status

Current

Introduction & key dates

circa 1952

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)

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

Also used in

Australia, USA

Chemical structure

Isomerism

A chiral molecule with 4 theoretical stereoisomers. The rel-(1R,2S,3R,4S)- isomer is the most effective herbicide.

Chemical formula

C₈H₁₀O₅

Canonical SMILES

C1CC2C(C(C1O2)C(=O)O)C(=O)O

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

GXEKYRXVRROBEV-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C8H10O5/c9-7(10)5-3-1-2-4(13-3)6(5)8(11)12/h3-6H,1-2H2,(H,9,10)(H,11,12)

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide, Algicide, Plant growth regulator

Substance group

Dicarboxylic acid

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Selective, contact, absorbed through leaves and roots

CAS RN

145-73-3

EC number

205-660-5

CIPAC number

154

US EPA chemical code

038901

PubChem CID

3225

Molecular mass

186.16

PIN (Preferred Identification Name)

(1E,2E,3E,4E)-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid

IUPAC name

7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid

CAS name

7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Classification (HRAC)

Herbicide Resistance Classification (WSSA)

Insecticide Resistance Classification (IRAC)

Not applicable

Fungicide Resistance Classification (FRAC)

Not applicable

Examples of recorded resistance

Physical state

Colourless to white crystals

Formulations

Property

Value

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

Hydout
Herbicide 273
Tribetol
Des-I-Cate
Aquathol

Example products using this active

Cerexagri
Pennwalt

Formulation and application details

Usually supplied as an aquatic suspension or a granular formulation.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

100000

High

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

280000

Methanol

76000

Dioxane

70000

Acetone

100

Benzene

Melting point (°C)

144

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

Not expected to self ignite; Not highly flammable

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

8.13 X 10⁰¹

Calculated

Log P

1.91

Low

Bulk density (g ml⁻¹)

1.43

Dissociation constant pKa) at 25 °C

3.4

pKa(2) 6.7

Vapour pressure at 20 °C (mPa)

2.09 X 10^-05

Low volatility

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

3.90 X 10^-11

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)

Non-persistent

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

Non-persistent

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

Best available data

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

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

K_d

Moderately mobile

K_oc

Notes and range

Other sources: K_oc 124 mL g⁻¹ (US3, DW3)

Freundlich

K_f

K_foc

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.75

Calculated

Low leachability

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

Value

1.22 X 10^-02

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Moderately mobile

Calculated

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

0.4

Whole fish

Low potential

CT₅₀ (days)

Not available

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

Rat

High

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)

> 5000

Anas platyrhynchos

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

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

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

> 78

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

1.3

Pimephales promelas 31 day

Moderate

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

> 32.5

Daphnia magna

Moderate

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

< 2.2

Daphnia magna

Moderate

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

> 150

Americamysis bahia

Low

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)

Non-target plants

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

Pseudokirchneriella subcapitata 10 day

Low

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

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)

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

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

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

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Other arthropod (1)

LR₅₀ g ha⁻¹

% Effect

Other arthropod (2)

LR₅₀ g ha⁻¹

% Effect

Soil micro-organisms

Mesocosm study data

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)

Rat

High

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

2000

Rabbit

Mammals - Inhalation LC₅₀ (mg l⁻¹)

0.68

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

MRLs

European

EU MRL pesticide database

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Toxic
Corrosive effects on gastrointestinal tract

Handling issues

Property

Value and interpretation

General

No information available

CLP classification 2013

Health: H301, H312, H315, H319, H335

EC Risk Classification

T - Toxic: R25
Xn - Harmful: R21
Xi - Irritant: R36/37/38

EC Safety Classification

S1/2, S36/37/39, S45

WHO Classification

II (Moderately hazardous)

UN Number

Waste disposal & packaging

TRANSLATIONS

Language

Name

English

endothal

French

endothal

German

Endothal

Danish

endothal

Italian

endotal

Spanish

endotal

Greek

endothal

Polish

endotal

Swedish

Hungarian

Dutch

endothal

Record last updated:	18/01/2021
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