Dimethenamid (Ref: SAN 582H)

Dimethenamid (Ref: SAN 582H)	Last updated: 02/03/2024
(Also known as: dimetenamid)

SUMMARY

Dimethanamid is a soil-applied herbicide. It is highly soluble in water and has a low volatility. It is not expected to be persistent in soil systems but may be persistent in water depending on local conditions. It is moderately toxic to most fauna and flora for which data is available. Dimethenamid is also moderately toxic to mammals if ingested and is a skin irritant and skin sensitizer.

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	Ecotoxicity Moderate alert: Birds acute ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Daphnia chronic ecotoxicity: Moderate; Bees acute contact ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate	Human health Moderate alert: Mammals acute toxicity: Moderate; Possible Carcinogen

GENERAL INFORMATION

Description

A soil-applied herbicide used to control a variety of broad-leaved weeds and grasses

Example pests controlled

Black grass; Chickweed; Cleavers; Mayweed; Forget-me-not; Speedwell; Shepherd's purse; Cranes-bill

Example applications

Field corn; Oilseed rape; Soybeans; Vines

Efficacy & activity

Availability status

Introduction & key dates

1996, introduced

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

Germany

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

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

Chemical structure

Isomerism

A chiral molecule, dimethenamid is an isomeric mixture of the M and P stereoisomers. Dimethenamid-P is the more biologically active isomer.

Chemical formula

C₁₂H₁₈ClNO₂S

Canonical SMILES

CC1=CSC(=C1N(C(C)COC)C(=O)CCl)C

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

JLYFCTQDENRSOL-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C12H18ClNO2S/c1-8-7-17-10(3)12(8)14(11(15)5-13)9(2)6-16-4/h7,9H,5-6H2,1-4H3S

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide

Substance groups

Chloroacetamide herbicide; Amide herbicide

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Absorbed via roots, little translocation. Inhibition of mitosis and cell division.

CAS RN

87674-68-8

EC number

618-045-5

CIPAC number

654

US EPA chemical code

129051

PubChem CID

91744

CLP index number

No data found

Molecular mass

275.79

PIN (Preferred Identification Name)

rac-2-chloro-N-(2,4-dimethylthiophen-3-yl)-N-[(2R)-1-methoxypropan-2-yl]acetamide

IUPAC name

(RS)-2-chloro-N-(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide

CAS name

2-chloro-N-(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide

Other status information

Chemical subject to PIC regulations

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

Yellow-brown viscous liquid

Related substances & organisms

dimethenamid-P

Formulations

Property

Value

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

BASF Corp
DuPont
King Tech

Example products using this active

Frontier
Leadoff
Optill

Formulation and application details

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

1200

High

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

Miscible

Acetone

Miscible

Ethyl acetate

Miscible

Hexane

Miscible

Toluene

Melting point (°C)

Boiling point (°C)

127

Degradation point (°C)

Flashpoint (°C)

(closed cup)

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

1.58 X 10⁰²

Calculated

Log P

2.2

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.2

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

0.37

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)

8.60 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

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)

Non-persistent

DT₅₀ (field)

Non-persistent

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU dossier lab studies DT₅₀ range 8-64 days, field studies DT₅₀ range 3.2-34.7 days; Other sources: DT₅₀ 20 days (DW4)

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

16.4

Slow

Note

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

Value

Stable

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.

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

K_oc

Notes and range

Freundlich

K_f

0.88

Mobile

K_foc

¹/_n

0.961

Notes and range

EU dossier kf range 0.32-1.6, K_foc range 40-114 mL g⁻¹,¹/_n range 0.929-0.979, Soils=5

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.41

Calculated

Transition state

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

Value

7.64 X 10^-02

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Mobile

Calculated

Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

2-((2,4-dimethyl-3-thienyl)-((1S)-2-methoxy-1-methyl-ethyl)amino)-2-oxo-acetic acid (Ref: M656PH023)

Major fraction

0.102

2-((2,4-dimethyl-3-thienyl)-((1S)-2-methoxy-1-methyl-ethyl)amino)-2-oxo-ethanesulfonic (Ref: M656PH027)

Major fraction

0.127

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)

397

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

33.3

Rat

High

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

1908

Colinus virginianus

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)

147

Eisenia foetida

Moderate

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

Soil micro-organisms

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

Dose: 6.3 kg ha⁻¹

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)

Moderate

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)

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 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 at dose 1.0 kg ha⁻¹

100

Aphidius rhopalosiphi

Beneficial insects (Predatory mites) as % Mortality at dose 1.0 kg ha⁻¹

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)

2.6

Oncorhynchus mykiss

Moderate

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

2.5

Oncorhynchus mykiss

Moderate

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

8.4

Danio rerio EC₅₀ Embryo

Moderate

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

Daphnia magna

Moderate

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

1.25

Daphnia magna LOEC

Moderate

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

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

4.8

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)

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

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

0.028

Lemna gibba

Moderate

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

0.062

Scenedesmus subspicatus

Moderate

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

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)

397

Rat

Moderate

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

4.99

Rat (nose only)

Other Mammal toxicity endpoints

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

0.02

Dog SF=100

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

0.25

Rat SF=100

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

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

0.04

Dog SF=100

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Occupational

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

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

US EPA - possible human carcinogen

Handling issues

Property

Value and interpretation

General

No information available

CLP classification 2013

Health: H302, H317, H332
Environment: H400, H410

WHO Classification

II (Moderately hazardous)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

dimethenamid

French

dimethenamid

German

Dimethenamid

Danish

dimethenamid

Italian

dimetenamid

Spanish

dimetenamida

Greek

Polish

dimetenamid

Swedish

Hungarian

dimethenamid

Dutch

Norwegian

Record last updated:	02/03/2024
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