Dazomet (Ref: N 521)

Dazomet (Ref: N 521)	Last updated: 15/03/2024
(Also known as: thiazone; tiazon; DMTT; BAS 00201N)

SUMMARY

Dazomet is a broad-spectrum pre-plant soil fumigant. It is highly soluble in water and somewhat volatile. Based on its chemical properties it is not expected to leach to groundwater. Data suggests it is not persistent in either soil or water systems. It is moderately toxic to mammals with a low potential for bioaccumulation. Dazomet is a recognised irritant. It has a moderate toxicity to most aquatic organisms and birds and honeybees but presents more of a risk to earthworms.

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: Very mobile	Ecotoxicity High alert: Earthworms acute ecotoxicity: High	Human health Moderate alert: Mammals acute toxicity: Moderate; Mammals chronic toxicity: Moderate; Genotoxic; Reproduction/development effects

GENERAL INFORMATION

Description

A multi-purpose, non-selective pre-plant soil fumigant

Example pests controlled

Nematodes; Soil fungi; Soil insects including wireworms, cutworms; Weed seeds

Example applications

Golf-greens; Turf; Ornamentals; Nursery sites; Potting soil; Strawberry plots; Tomatoes; Tobacco

Efficacy & activity

Availability status

Current

Introduction & key dates

1967, first registered USA

UK regulatory status

UK COPR regulatory status

Approved

Date COPR inclusion expires

31/05/2026

UK LERAP status

No data

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Belgium/Netherlands

Date EC 1107/2009 inclusion expires

31/08/2026

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

Australia, USA

Chemical structure

Isomerism

None

Chemical formula

C₅H₁₀N₂S₂

Canonical SMILES

CN1CN(C(=S)SC1)C

Isomeric SMILES

International Chemical Identifier key (InChIKey)

QAYICIQNSGETAS-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C5H10N2S2/c1-6-3-7(2)5(8)9-4-6/h3-4H2,1-2H3

2D structure diagram/image available?

Yes

General status

Pesticide type

Insecticide, Fungicide, Herbicide, Fumigant

Substance groups

Dithiocarbamate insecticide; Carbamate insecticide; Dithiocarbamate herbicide; Carbamate herbicide; Dithiocarbamate fungicide; Carbamate fungicide; Fumigant pesticide

Minimum active substance purity

960 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Releases methyl isothiocyanate

CAS RN

533-74-4

EC number

208-576-7

CIPAC number

146

US EPA chemical code

035602

PubChem CID

10788

CLP index number

613-008-00-X

Molecular mass

162.3

PIN (Preferred Identification Name)

3,5-dimethyl-1,3,5-thiadiazinane-2-thione

IUPAC name

3,5-dimethyl-1,3,5-thiadiazinane-2-thione

CAS name

tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Not known

Herbicide Resistance Class (WSSA MoA class)

Not known

Insecticide Resistance Class (IRAC MoA class)

Fungicide Resistance Class (FRAC MOA class)

M03

Examples of recorded resistance

Physical state

Colourless crystals

Related substances & organisms

dazomet-sodium

Formulations

Property

Value

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

Certis
BASF
Stauffer
Union Carbide
Hopkins Agriculture

Example products using this active

Basamid Granules
Mico-Fume
Mylone

Formulation and application details

Often supplied in granule formulations applied directly to the soil surface causing methyl isothiocyanate to be released.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

3500

High

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

89700

Acetone

28500

Ethyl acetate

21300

Methanol

8600

Toluene

Melting point (°C)

105

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

150

Flashpoint (°C)

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

4.27 X 10⁰⁰

Calculated

Log P

0.63

Low

Fat solubility of residues

Solubility

Insoluble

Data type

Regulatory data based on LogP

Density (g ml⁻¹)

1.37

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

1.1

Low volatility. 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)

5.10 X 10^-05

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

pH 6.2 solution: 208nm = 7308, 228.5nm = 4209, 246nm = 6209, 260nm = 4631, 283nm = 11378, 300nm = 3682

Surface tension (mN m⁻¹)

64.9

at 20°C

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

0.52

Non-persistent

DT₅₀ (lab at 20 °C)

0.52

Non-persistent

DT₅₀ (field)

1.2

Non-persistent

DT₉₀ (lab at 20 °C)

4.4

Non-persistent

DT₉₀ (field)

3.8

DT₅₀ modelling endpoint

Note

EU dossier lab studies DT₅₀ range: 0.07-5.4 days, DT₉₀ range 0.8-18.0 days; field studies DT₅₀ 0.9-1.6 days, DT₉₀ range 2.6-4.6 days; Other sources: DT₅₀ 7 days (DW3)

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

0.35

Fast

Note

DT₅₀: 4 hrs in daylight, 7.3 hours in dark

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

Value

0.2

Non-persistent

Note

Slightly vaiable with pH: DT₅₀ 0.4 days at pH 5, 0.1 days at pH 9 all at 25 °C

Water-sediment DT₅₀ (days)

0.52

Fast

Water phase only DT₅₀ (days)

0.45

Fast

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

Very mobile

K_oc

Notes and range

Freundlich

K_f

1.13

Moderately mobile

K_foc

260

¹/_n

0.838

Notes and range

EU dossier K_f range 0.808-1.834, kfoc range 129-394 mL g⁻¹, ¹/_n range 0.805-0.889, Soils=4

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

0.13

Calculated

Low leachability

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

Value

4.75 X 10^-04

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Very mobile

Calculated

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

0.85

Calculated using the Atkinson method. Assumed 0.8E+06 OH/cm³, 24 hr

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

3.1

Estimated

Low potential

CT₅₀ (days)

Not available

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

methyl isothiocyanate (Ref: SN-32866)

Major fraction

0.740

formaldehyde

Major fraction

0.205

methylamine

Minor fraction

0.092

2,4-dimethyl-1,2,4-thiadiazolidine-5-thione

Major fraction

0.450

ethyl-N-(3-hydroxyphenyl)-carbamate

Major fraction

0.490

DT50 soil = 101 days

methylurea

Minor fraction

1,3-dimethylurea

Minor fraction

formic acid

Minor fraction

0.081

Known groundwater metabolites

Metabolite

EC SANCO/221/2000 relevancy

ADI (mg kg⁻¹ bodyweight day⁻¹)

WHO drinking water guidance value (μg L⁻¹ day⁻¹)

methyl isothiocyanate (Ref: SN-32866)

Relevancy unknown

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Metabolising enzymes

1-(hydroxysulfanyl)-N-methyl-1-thioxomethanamine

MATM

Water

methyldithiocarbamic acid

metam

Water

1,3-dimethylthiourea

DMTU

Plant; Water

1,2,4-dithiazolidine-3-thione

Metabolite 139

Water (hydrolysis)

1,3,5-trimethyl-1,3,5-triazinane-2-thione

Unknown

1,3-thiazetidine 1-oxide

Water (photolysis)

(dimethylamino)methanethiol

Water (photolysis)

1-methylthiourea

MMTU

Plant

1,1,3-trimethylthiourea

TMTU

Plant

1-(hydroxysulfanyl)-N-methyl-1-thioxomethanamine

Metabolite 123

Water (hydrolysis)

[(disulfanylcarbonothioyl)amino]methane

Metabolite 137

Water (hydrolysis)

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

415

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat

(ppm diet)

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

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

> 415

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

197 mg kg bw⁻¹ day⁻¹

Colinus virginianus

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

10.6

Colinus virginianus NOEL

Moderate

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

6.5

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)

> 50

Apis mellifera

Moderate

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 10

Apis mellifera

Moderate

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) as % Mortality at dose 485 kg ha⁻¹

-3.4

Poecilus cupreus corr

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

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

0.3

Lepomis macrochirus

Moderate

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

26.0

Lepomis macrochirus 96 hr

Low

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

> 0.16

Danio rerio Embryo

Moderate

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

19.0

Daphnia magna

Moderate

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

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

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

0.5

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)

3.5

Lemna gibba

Moderate

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

0.275

Pseudokirchneriella subcapitata

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)

415

Rat

Moderate

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

1000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 7.3

Rat

Other Mammal toxicity endpoints

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

0.01

Rat 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)

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

0.015

Rat SF=100

Dermal penetration studies (%)

3.0

Dangerous Substances Directive 76/464

Exposure Routes

Public

No unacceptable risks to bystanders identified

Occupational

No unacceptable risks to operators or other workers identified

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

GB MRL levels for some commodities subject to change in late 2021

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

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

No data found

General human health issues

Possible liver toxicant

Handling issues

Property

Value and interpretation

General

Corrosive
Prevent generation of dust
Not explosive or oxidising
IMDG Transport Hazard Class 6.1
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Health: H302, H319
Environment: H400, H410

WHO Classification

II (Moderately hazardous)

UN Number

UN2771

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

Chemically stable at ambient conditions

TRANSLATIONS

Language

Name

English

dazomet

French

dazomet

German

Dazomet

Danish

dazomet

Italian

dazomet

Spanish

dazomet

Greek

dazomet

Polish

dazomet

Swedish

dazomet

Hungarian

dazomet

Dutch

dazomet

Norwegian

Record last updated:	15/03/2024
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