Dimethrin (Ref: ENT 21170 )

Dimethrin (Ref: ENT 21170 )	Last updated: 19/08/2023
(Also known as: dimetrin; dimethrine; SHA 034101)

SUMMARY

Dimethrin is a pyrethroid ester insecticide mainly used for public health applications. It is largely considered obsolete. It has a low aqueous solubility, low volatility and not considered to be highly mobile. It is toxic to fish. Dimethrin is not particularly toxic to mammals via the oral route and is a recognised irritant.

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 Low alert: Drainflow: Non-mobile Warning: Significant data are missing	Ecotoxicity Moderate alert: Fish acute ecotoxicity: Moderate Warning: Significant data are missing	Human health Moderate alert: Neurotoxicant Warning: Significant data are missing

GENERAL INFORMATION

Description

An obsolete, pyrethroid insecticide

Example pests controlled

Mosquitoes; Body lice; Stable flies; Blowfiles; Cattle flies

Example applications

Public health situations; Public buildings; Livestock buildings

Efficacy & activity

Availability status

Considered obsolete but may be available in some countries

Introduction & key dates

1958, first reported

UK regulatory status

UK COPR regulatory status

Not approved

Date COPR inclusion expires

Not applicable

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

Not applicable

EU Candidate for substitution (CfS)

Not applicable

Listed in EU database

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

Isomeric. Substance has mixed sterochemistry.

Chemical formula

C₁₉H₂₆O₂

Canonical SMILES

CC1=CC(=C(C=C1)COC(=O)C2C(C2(C)C)C=C(C)C)C

Isomeric SMILES

International Chemical Identifier key (InChIKey)

FHNKBSDJERHDHZ-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C19H26O2/c1-12(2)9-16-17(19(16,5)6)18(20)21-11-15-8-7-13(3)10-14(15)4/h7-10,16-17H,11H2,1-6H3

2D structure diagram/image available?

Yes

General status

Pesticide type

Insecticide, Miticide

Substance groups

Pyrethroid insecticide; Pyrethroid ester insecticide

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Sodium channel modulator, acts on the nervous system of insects

CAS RN

70-38-2

EC number

No data found

CIPAC number

None allocated

US EPA chemical code

034101

PubChem CID

6265

CLP index number

No data found

Molecular mass

286.41

PIN (Preferred Identification Name)

(2,4-dimethylphenyl)methyl (1E,3E)-2,2-dimethyl-3-(2-methylprop-1-en-1-yl)cyclopropane-1-carboxylate

IUPAC name

2,4-dimethylbenzyl (1RS,3RS;1RS,3SR)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate

CAS name

(2,4-dimethylphenyl)methyl 2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylate

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Classification (HRAC)

Not applicable

Herbicide Resistance Classification (WSSA)

Not applicable

Insecticide Resistance Classification (IRAC)

Fungicide Resistance Classification (FRAC)

Not applicable

Examples of recorded resistance

Sitophilus granarius

Physical state

Amber coloured liquid

Formulations

Property

Value

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

Example products using this active

Obsolete - not thought to be commercially available for crop protection applications

Formulation and application details

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

0.036

Low

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

Melting point (°C)

Boiling point (°C)

175

at 3.8 mmHg

Degradation point (°C)

Flashpoint (°C)

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

3.72 X 10⁰⁶

Calculated

Log P

6.57

High

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

2.293

Low volatility

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

7.711

Moderately 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

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

Non-mobile

K_oc

31000

Notes and range

Estimated

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

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)

CT₅₀ (days)

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 40000

Rat

Low

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)

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)

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)

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)

0.32

Lepomis macrochirus

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

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

Low (class I)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 40000

Rat

Low

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

4900

Rabbit

Mammals - Inhalation LC₅₀ (mg l⁻¹)

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

Occupational exposure tmay occur through inhalation and dermal contact but risk is very low as substance is obsolete

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

; ; ; ;

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

Suspected liver toxicant
May cause contact dermatitis and respiratory allergies

Handling issues

Property

Value and interpretation

General

No information available

CLP classification 2013

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

dimethrin

French

dimethrine

German

Danish

Italian

Spanish

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	19/08/2023
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