Metam-sodium (Ref: N 869)

Metam-sodium (Ref: N 869)	Last updated: 24/10/2024
(Also known as: metham; methylcarbamodithioic acid, sodium salt; carbam; carbathion; metam; metham-sodium)

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 Moderate alert: Birds acute ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Bees acute contact ecotoxicity: Moderate; Bees acute unknown ecotoxicity: Moderate	Human health High alert: Reproduction/development effects

GENERAL INFORMATION

Description

A multi-action crop protection agent used as a pre-planting soil sterilant

Example pests controlled

Weed and disease suppression including control of annual bluegrass, chickweed, ragweed, nutgrass, morning glory; Sclerotina, club root and Rhizoctonia; Damping off; Some nematodes

Example applications

Vegetables; Fruit; Ornamentals; Fiber crops; Cover crops; Leafy salads

Efficacy & activity

Efficacy is well established via extensive use and field trials

Availability status

Current

Introduction & key dates

1951, first reported

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

30/06/2025

GB LERAP status

No data

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Belgium

Date EC 1107/2009 inclusion expires

30/11/2025

EU Candidate for substitution (CfS)

Yes - low ADI / ARfD / AOEL

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

Morocco

Chemical structure

Isomerism

None

Chemical formula

C₂H₄NNaS₂

Canonical SMILES

CNC(=S)[S-].[Na+]

Isomeric SMILES

International Chemical Identifier key (InChIKey)

AFCCDDWKHLHPDF-UHFFFAOYSA-M

International Chemical Identifier (InChI)

InChI=1S/C2H5NS2.Na/c1-3-2(4)5;/h1H3,(H2,3,4,5);/q;+1/p-1

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide; Fungicide; Nematicide; Insecticide; Other substance

Other bioactivity & uses

Biocide; Slimicide; Preservative; Disinfectant; Algicide

Substance groups

Carbamate fungicide; Dithiocarbamate fungicide; Carbamate herbicide; Dithiocarbamate herbicide; Carbamate nematicide; Dithiocarbamate nematicide

Minimum active substance purity

965 g kg⁻¹

Known relevant impurities

EU 2023 dossier - N,N’-dimethylthiourea 18.7 g kg⁻¹

Substance origin

Synthetic

Mode of action

Soil fumigant, binds to oxygen carrying molecules and prevents tissues from using oxygen. Multi-site activity.

CAS RN

137-42-8

EC number

205-293-0

CIPAC number

20.011

US EPA chemical code

039003

PubChem CID

5366415

CLP index number

006-013-00-8

Molecular mass

129.19

PIN (Preferred Identification Name)

IUPAC name

sodium N-methyldithiocarbamate

CAS name

methylcarbamodithioic acid sodium salt

Other status information

Marine Pollutant

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

A/C1

Herbicide Resistance Class (WSSA MoA class)

1/5

Insecticide Resistance Class (IRAC MoA class)

Fungicide Resistance Class (FRAC MOA class)

M03

Examples of recorded resistance

Physical state

White to pale yellow crystalline powder

Related substances & organisms

metam

metam-ammonium

metam-potassium

N,N-dimethylthiourea

Formulations

Property

Value

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

United Phosphorus
New Farm Australia
Sinochem
Vapam

Example products using this active

Discovery
Sistan
Maposol
Ucetam

Formulation and application details

Often supplied as a soluble concentrate or liquid fumigant

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

578290

High

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

212.6

n-Heptane

261.1

Xylene

203.2

Ethyl acetate

218.8

Acetone

Melting point (°C)

86.5

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

150

Flashpoint (°C)

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

1.23 X 10^-03

Calculated

Log P

-2.91

Low

Fat solubility of residues

Solubility

Insoluble

Data type

Regulatory data basd on LogP

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

2.99

pKa(2) = 11.06

Vapour pressure at 20 °C (mPa)

57.4

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)

8.34 X 10^-06

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

Neutral solution: 205.0nm = 7502.8, 248.0nm = 7942.3, 280.0nm = 9924.0, 290nm >10
Acidic solution: can not measured due to rapid hydrolysis
Basic solution: 248.0nm = 8042.5, 280.0nm = 9796.8, 290nm >10

Surface tension (mN m⁻¹)

72.0

at 21°C

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Not readily biodegradable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

Non-persistent

DT₅₀ (lab at 20 °C)

0.01

Non-persistent

DT₅₀ (field)

Non-persistent

DT₉₀ (lab at 20 °C)

0.02

Non-persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU Dossier lab studies DT₅₀ range 4-22 minutes, DT₉₀ range 13-72 minutes; Other sources: up to 7 days

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

0.05

Fast

Note

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

Value

2.2

Non-persistent

Note

pH sensitive: DT₅₀ 1.9 days at pH 5, 4.5 days at pH 9, all at 25 °C

Water-sediment DT₅₀ (days)

1.0

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)

Mobile

K_oc (mL g⁻¹)

Notes and range

EU dossier 2023 data

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.28

Calculated

Transition state

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

Value

1.54 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)

0.03

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

0.829

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)

Relevant

0.004

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

methyl isothiocyanate (Ref: SN-32866)

MITC

Surface water; Sediment

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

896

Rat as metam

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

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

> 12

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

211

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

> 448 mg kg bw⁻¹ day⁻¹

Colinus virginianus

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)

> 36.2

Apis mellifera

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)

> 36.2

Apis mellifera

Moderate

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)

> 0.175

Lepomis macrochirus

Moderate

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

0.464

Oncorhynchus mykiss

Moderate

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

> 0.25

Danio rerio Embryo 1.8 day

Moderate

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

0.99

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)

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 (free-floating, growth) - Acute 7 day EC₅₀, biomass (mg l⁻¹)

Aquatic plants (rooted, growth) - Acute 14 day EC₅₀, biomass (mg l⁻¹)

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

1.08

Pseudokirchneriella subcapitata

Moderate

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

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)

896

Rat as metam

Moderate

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

2.54

Rat 4 hr (whole body)

Other Mammal toxicity endpoints

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

0.001

Dog SF=100 as metam

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

0.1

Rat SF=100 as metam

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

0.1

Rabbit SF=100 as metam

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

0.001

Dog SF=100 as metam

Dermal penetration studies (%)

1-12

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Negligible risk to bystanders
Low risk of exposure via diet

Occupational

Low risk to operators and other workers utilising PPE/PPC

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

Mainly eliminated via urine (85%) with remainder via expelled air

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

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

Possible liver and urinary tract toxicant
US EPA - probable human carcinogen, CLP data - suspected carcinogen
Possible liver toxicant

Handling issues

Property

Value and interpretation

General

Corrosive
May liberate toxic gas when in contact with acids
Not explosive or oxidising
IMDG Transport Hazard Class 6.1
Not likely to autoignite

CLP classification 2013

Health: H372, H371, H361d, H351, H341, H332, H302, H314, H317
Environment: H400, H410
Handling: H290

WHO Classification

II (Moderately hazardous)

UN Number

UN2757

Waste disposal & packaging

Spilled product is a hazardous waste and disposal must be at an approved manner
Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

metam-sodium

French

metam

German

Metam

Danish

metam

Italian

metam

Spanish

metam

Greek

Polish

metam

Swedish

Hungarian

Dutch

metam-natrium

Norwegian

Record last updated:	24/10/2024
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