Methyl isothiocyanate (Ref: SN-32866)

Methyl isothiocyanate (Ref: SN-32866)	Last updated: 23/08/2024
(Also known as: methyl mustard oil; MITC; isothiocyanic acid methyl ester; MIT; R014821)

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 High alert: Drainflow: Mobile	Ecotoxicity High alert: Fish acute ecotoxicity: High; Fish chronic ecotoxicity: High; Daphnia acute ecotoxicity: High; Daphnia chronic ecotoxicity: High; Earthworms acute ecotoxicity: High	Human health High alert: Genotoxic; Reproduction/development effects Warning: Significant data are missing

GENERAL INFORMATION

Description

A highly toxic multipurpose soil fumigant. Also a pesticide transformation product and used in the production of many pesticides and other chemicals.

Example pests controlled

Nematodes; Various soil insects; Fungal pathogens; Weed seeds

Example applications

Efficacy & activity

Availability status

Introduction & key dates

GB regulatory status

GB COPR regulatory status

Not approved

Date COPR inclusion expires

Not applicable

GB LERAP status

No UK approval for use as a pesticide

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

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

None

Chemical formula

C₂H₃NS

Canonical SMILES

CN=C=S

Isomeric SMILES

International Chemical Identifier key (InChIKey)

LGDSHSYDSCRFAB-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C2H3NS/c1-3-2-4/h1H3

2D structure diagram/image available?

Yes

General status

Pesticide type

Metabolite, Fungicide, Nematicide, Herbicide, Insecticide

Metabolite Type

Soil, Groundwater

Substance groups

Fumigant pesticide

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Fumigant with contact action

CAS RN

556-61-6

EC number

209-132-5

CIPAC number

None allocated

US EPA chemical code

068103

PubChem CID

11167

CLP index number

615-002-00-2

Molecular mass

73.11

PIN (Preferred Identification Name)

IUPAC name

methyl isothiocyanate

CAS name

isothiocyanatomethane

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Not applicable

Herbicide Resistance Class (WSSA MoA class)

Not applicable

Insecticide Resistance Class (IRAC MoA class)

Not known

Fungicide Resistance Class (FRAC MOA class)

Not known

Examples of recorded resistance

Physical state

Colourless crystalline solid

Can be a metabolite of:

Parent

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

imazalil sulfate

Soil

Minor fraction

metam-potassium

Groundwater

Relevant

metam-potassium

Soil

0.829

Major fraction

metam-sodium

Soil

0.829

Major fraction

metam-sodium

Groundwater

Relevant

dazomet

Soil

0.740

Major fraction

imazalil

Soil

0.096

Minor fraction

dazomet

Groundwater

Relevancy unknown

metam

Soil

0.829

Major fraction

metam

Groundwater

Relevant

metam-ammonium

Soil

0.829

Major fraction

metam-ammonium

Groundwater

Relevant

imazalil nitrate

Soil

Minor fraction

Formulations

Property

Value

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

Schering

Example products using this active

Trapex

Formulation and application details

Usually supplied as an emulsifiable concentrate for drip irrigation systems

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

8940

High

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

Melting point (°C)

Boiling point (°C)

119

Degradation point (°C)

Flashpoint (°C)

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

1.12 X 10⁰¹

Calculated

Log P

1.05

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.07

Dissociation constant pKa) at 25 °C

12.3

Strong base

Vapour pressure at 20 °C (mPa)

1739000

Highly volatile. If applied directly to plants or soil, drift is a concern & mitigation is advisable

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

14.2

Moderately volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

Neutral soln: 235nm=635, 283nm=65, 321nm=17
Alkaline soln: 276nm=46, 320nm=5, 290nm=>10
Acidic soln: 235nm=635, 283nm=23, 290nm=>10

Surface tension (mN m⁻¹)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

2.1

Non-persistent

DT₅₀ (lab at 20 °C)

2.1

Non-persistent

DT₅₀ (field)

3.2

Non-persistent

DT₉₀ (lab at 20 °C)

6.99

Non-persistent

DT₉₀ (field)

13.1

DT₅₀ modelling endpoint

Note

EU dossier (2023 metam) lab studies DT₅₀ (normalised) range: 1.08-3.24 days, DT₉₀ (normalised) range 3.6-10.78 days Soils=4;Ffield studies DT₅₀ (normalised) range 1.2-5.0 days, DT₉₀ (measured) 4.1-16.5 days, Soils=4; EU dossier (dazomet) lab studies range 5-32.7 days; Other literature studies Lab range - 24 soils, nursery and forest, various app rates

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

Moderately fast

Note

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

Value

Moderately persistent

Note

pH sensitive. DT40 50 days at pH4, 11 days at pH9

Water-sediment DT₅₀ (days)

0.37

Fast

Water phase only DT₅₀ (days)

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)

0.56

Mobile

K_foc (mL g⁻¹)

21.7

¹/_n

0.86

Notes and range

EU dossier (Metam, 2023) K_f range 0.21-1.38 mL g⁻¹, K_foc range 9.0-71.7 mL g⁻¹, ¹/_n range 0.755-9.1, Soils=10

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.35

Calculated

Low leachability

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

Value

2.96 X 10^-03

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

1889

Calculated using the Atkinson method. Assumed 1.5E+06 OH/cm³, 24 hr

Substance of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

2.6

Estimated

Low potential

CT₅₀ (days)

Not available

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 100

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)

127

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)

4.0

Eisenia foetida

High

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

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)

Beneficial insects (Predatory mites)

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)

0.0531

Oncorhynchus mykiss

High

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

0.005

Oncorhynchus mykiss 28 day

High

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

0.137

Danio rerio Embryo

Moderate

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

0.076

Daphnia magna

High

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

0.00625

Daphnia magna

High

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (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)

0.59

Lemna gibba

Moderate

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

0.58

Pseudokirchneriella subcapitata

Moderate

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

> 0.125

Unknown species

Moderate

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)

> 100

Rat

Moderate

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

1290

Rabbit

Mammals - Inhalation LC₅₀ (mg l⁻¹)

0.54

Rat 4 hr (whole body)

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)

0.03

Rat SF=100

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

0.004

Rabbit SF=300

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

0.004

Dog. SF=100

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Some bystander risk identified via spray drift exposure

Occupational

May be fatal if absorbed through the skin
Respiratory equipment required to mitigate risk
Risks identified in glasshouse environments

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

0.1

EU Dir 89/778/EC limit

Mammalian dose elimination route and rate

80-85% excreted with urine within approx. 80 hrs

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

Eye irritant

Phototoxicant

General human health issues

Highly toxic by ingestion
Harmful via skin exposure and inhalation
Possible thyroid toxicant
US EPA - probable human carcinogen, CLP data - suspected carcinogen

Handling issues

Property

Value and interpretation

General

Corrosive
Not explosive or oxidising

CLP classification 2013

Health: H301, H312, H314; H317; H335, H351, H372
Environment: H400, H410

WHO Classification

II (Moderately hazardous)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

methyl isothiocyanate

French

isothiocyanate de methyle

German

Methylisothiocyanat

Danish

methylisothiocyanat

Italian

Isotiocianato di metile

Spanish

isotiocianato de metilo

Greek

Polish

metyloizotiocyjanian

Swedish

Hungarian

Dutch

methylisothiocyanaat

Norwegian

Record last updated:	23/08/2024
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