| metam-sodium (Ref: N 869) |
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Environmental Fate - Ecotoxicology - Human Health - A to Z Index - Home
GENERAL INFORMATION 
for metam-sodium
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
Efficacy & activity: -
Availability status: Current
Introduction & key dates: 1951, first reported
EC Regulation 1107/2009 (repealing 91/414):
| Status | Approved |
| Dossier rapporteur/co-rapporteur | Belgium |
| Date inclusion expires | 30/06/2022 |
| EU Candidate for substitution (CfS) | Yes - low ADI / ARfD / AOEL |
| Listed in EU database | Yes |
Approved for use (
) or known to be used (
) in the following European countries: 
AT |
BE |
BG |
CY |
CZ |
DE |
DK |
EE |
EL |
ES |
FI |
FR |
HR |
HU |
IE |
IT |
LT |
LU |
LV |
MT |
NL |
PL |
PT |
RO |
SE |
SI |
SK |
UK |
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Also used in: Australia, USA
Chemical structure:
| Isomerism | - |
| Chemical formula | C2H4NNaS2 |
| Canonical SMILES | CNC(=S)[S-].[Na+] |
| Isomeric SMILES | No data |
| 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 |
| Structure diagram/image available? | Yes |
General status:
| Pesticide type | Herbicide, Fungicide, Nematicide, Insecticide | |
| Substance group | Carbamate | |
| Minimum active substance purity | 965 g/kg | |
| Known relevant impurities | EU dossier - methylisothiocyanate <12g/kg dry wt, N,N’-dimethylthiourea 23.0 g/kg dry wt | |
| Substance origin | Synthetic | |
| Mode of action | Soil fumigant, binds to oxygen carrying molecules and prevents tissues from using oxygen. | |
| CAS RN | 137-42-8 | |
| EC number | 205-293-0 | |
| CIPAC number | 20.011 | |
| US EPA chemical code | 039003 | |
| PubChem CID | 5366415 | |
| Molecular mass (g mol-1) | 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 Classification (HRAC) | Z | |
| Herbicide Resistance Classification (WSSA) | - | |
| Insecticide Resistance Classification (IRAC) | Not applicable | |
| Fungicide Resistance Classification (FRAC) | Not known | |
| Examples of recorded resistance | - | |
| Physical state | White crystalline powder | |
| Related substances & organisms | ||
Formulations:
| Property |
Value | |||
| Example manufacturers & suppliers of products using this active now or historically |
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| Example products using this active |
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| UK LERAP status | None | |||
| Formulation and application details | Often supplied as a soluble concentrate or liquid fumigant. | |||
ENVIRONMENTAL FATE
for metam-sodium
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Solubility - In water at 20oC (mg l-1) | 578290 | A5 | High | |
| Solubility - In organic solvents at 20oC (mg l-1) | 212.6 | A5 - n-Heptane | - | |
| 261.1 | A5 - Xylene | - | ||
| 203.2 | A5 - Ethyl acetate | - | ||
| 218.8 | A5 - Acetone | - | ||
| Melting point (oC) | 88.5 | A5 | - | |
| Boiling point (oC) | Decomposes before boiling | A5 | - | |
| Degradation point (oC) | 150 | A5 | - | |
| Flashpoint (oC) | 97 | A5 | - | |
| Octanol-water partition coefficient at pH 7, 20oC | P | 1.23 X 10-03 | Calculated | - |
| Log P | -2.91 | A5 | Low | |
| Bulk density (g ml-1)/Specific gravity | - | - | - | |
| Dissociation constant (pKa) at 25oC | 2.99 | A5 | - | |
| Note: pKa(2) = 11.06 | ||||
| Vapour pressure at 20oC (mPa) | 57.5 | A5 | Highly volatile | |
| Henry's law constant at 25oC (Pa m3 mol-1) | 8.34 X 10-06 | A5 | Non-volatile | |
GUS leaching potential index  |
-5.50 | Calculated | Low leachability | |
| SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate |
Value | 2.56 X 10-05 | Calculated | - |
| Note | - | |||
| Potential for particle bound transport index |
- | Calculated | Low | |
| 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 | A5 | - | |
| Surface tension (mN m-1) | 72.0 | A5 at 21oC | - | |
Degradation:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
General biodegradability | - |
| Soil degradation (days) (aerobic) | DT50 (typical) | 7 | C4 | Non-persistent |
| DT50 (lab at 20oC) | 0.01 | A5 | Non-persistent | |
| DT50 (field) | 7 | C4 | Non-persistent | |
| DT90 (lab at 20oC) | 0.03 | A5 | - | |
| 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 on plant matrix | Value | - | - | - |
| Note | - | |||
| Dissipation rate RL50 on and in plant matrix | Value | - | - | - |
| Note | - | |||
| Aqueous photolysis DT50 (days) at pH 7 | Value | 0.05 | A5 | Fast |
| Note | - | |||
| Aqueous hydrolysis DT50 (days) at 20oC and pH 7 | Value | 2.2 | A5 | Non-persistent |
| Note | pH sensitive: DT50 1.9 days at pH 5, 4.5 days at pH 9, all at 25 degC | |||
| Water-sediment DT50 (days) | 0.07 | A5 | Fast | |
| Water phase only DT50 (days) | - | - | - | |
Soil adsorption and mobility:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Linear | Kd | - | DW3 | Mobile |
| Koc | 17.8 | |||
| Notes and range | EU dossier data | |||
| Freundlich | Kf | - | - | - |
| Kfoc | - | |||
| 1/n | - | |||
| Notes and range | - | |||
| pH sensitivity | - | |||
Key metabolites:
| Metabolite | Formation medium | Estimated maximum occurrence fraction | 1107/2009 relevancy |
|
| methyl isothiocyanate (Ref: SN-32866) |
Soil | 0.829 | Major fraction, Relevant | |
Other known metabolites:
| Metabolite name and reference | Aliases | Formation medium / Rate | Estimated maximum occurrence fraction | Metabolising enzymes |
| N,N’-dimethylthiourea Note: Toxicologically relevant |
DMTU | Groundwater; Water/sediment | - | - |
| dimethylurea | DMU | Water/sediment | - | - |
| - | DMTD | Water/sediment | - | - |
| IMPURITY: | - | - | - | - |
| N,N’-dimethylthiourea | DMTU | Present in product | - | - |
ECOTOXICOLOGY
for metam-sodium
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Bio-concentration factor | BCF (l kg-1) | 0.03 | Q2 Estimated | Low potential |
| CT50 (days) | Not available | - | ||
| Mammals - Acute oral LD50 (mg kg-1) | 896 | A5 Rat | Moderate | |
| Mammals - Short term dietary NOEL | (mg kg-1) | - | - | - |
| (ppm diet) | - | - | ||
| Birds - Acute LD50 (mg kg-1) | 211 | A5 Colinus virginianus | Moderate | |
| Birds - Short term dietary (LC50/LD50) | > 448 mg kg bw-1 day-1 | A4 Colinus virginianus | - | |
| Fish - Acute 96 hour LC50 (mg l-1) | > 0.175 | A5 Lepomis macrochirus | Moderate | |
| Fish - Chronic 21 day NOEC (mg l-1) | - | - | - | |
| Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) | 0.99 | A5 Daphnia magna | Moderate | |
| 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) | - | - | - | |
| Non-target plants | - | - | - | |
| - | - | - | ||
| Algae - Acute 72 hour EC50, growth (mg l-1) | 1.08 | A5 Pseudokirchneriella subcapitata | Moderate | |
| Algae - Chronic 96 hour NOEC, growth (mg l-1) | - | - | - | |
| Honeybees | Contact acute 48 hour LD50 (μg bee-1) | > 36.2 | F4 Apis mellifera | Moderate |
| Oral acute 48 hour LD50 (μg bee-1) | - | - | - | |
| Unknown mode acute 48 hour LD50 (μg bee-1) | > 36.2 | F3 | Moderate | |
| Earthworms - Acute 14 day LC50 (mg kg-1) | - | - | - | |
| Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1) | - | - | - | |
| Other soil macro-organisms - e.g. Collembola | LR50 / EC50 / NOEC / % Effect | - | - | - |
| Other arthropod (1) | LR50 g ha-1 | - | - | - |
| % Effect | -14.6 | Reproduction Dose: 608 kg ha-1 A5 Aleochara bilineata |
- | |
| Other arthropod (2) | LR50 g ha-1 | - | - | - |
| % Effect | - | - | - | |
| Soil micro-organisms | - | - | - | |
| Mesocosm study data | NOEAEC mg l-1 | - | - | - |
| NOEAEC mg l-1 | - | - | - | |
HUMAN HEALTH AND PROTECTION
for metam-sodium
General:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Threshold of Toxicological Concern (Cramer Class) |
High (class III) | - | - | |
| Mammals - Acute oral LD50 (mg kg-1) | 896 | A5 Rat | Moderate | |
| Mammals - Dermal LD50 (mg kg-1 body weight) | > 2000 | A5 Rat | - | |
| Mammals - Inhalation LC50 (mg l-1) | 2.54 | A5 Rat, 4 hr (whole body) | - | |
| Other Mammal toxicity endpoints | - | - | ||
| ADI - Acceptable Daily Intake (mg kg-1bw day-1) | 0.001 | A5 Dog, SF=100 | - | |
| ARfD - Acute Reference Dose (mg kg-1bw day-1) | 0.1 | A5 Rat, SF=100 | - | |
| AAOEL - Acute Acceptable Operator Exposure Level (mg kg-1 bw day-1) | - | - | - | |
| AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) | 0.001 | A5 Dog, SF=100 | - | |
| Dermal penetration studies (%) | 1-12 | A5 concentration dependent | - | |
| Dangerous Substances Directive 76/464 | - | - | - | |
| Exposure Limits | - | - | - | |
| Exposure Routes | Public | Negligible risk to bystanders Low risk of exposure via diet |
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| Occupational | Low risk to operators and other workers utilising PPE/PPC | |||
| European MRLs | Click here for the EU MRL pesticide database | |||
| Drinking Water Standards | - | - | - | |
| Drinking Water MAC (μg l-1) | - | - | - | |
Health issues:
| Carcinogen | Mutagen | Endocrine disrupter | Reproduction / development effects | Cholinesterase inhibitor | Neurotoxicant | |||
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- |
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| Respiratory tract irritant | Skin irritant | Skin sensitiser | Eye irritant | Phototoxicant | ||||
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| General human health issues | Possible liver and urinary tract toxicant USEPA - probable human carcinogen |
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: Yes, known to cause a problem
: No, known not to cause a problem
: Possibly, status not identified
- : No data found
Handling issues:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| General |
Corrosive May liberate toxic gas when in contact with acids Not explosive or oxidising IMDG Transport Code is usually 8 |
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| CLP classification 2013 | Health: H302, H314, H317 Environment: H400, H410 |
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| EC Risk Classification |
Reproduction risk category 3: R63 Xn - Harmful: R22, R43 H - Handling risks: R31, R34 N - Dangerous for the environment: R50, R53 |
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| EC Safety Classification |
S1/2, S26, S36/37/39, S45, S60, S61 | |||
| WHO Classification | II | - | Moderately hazardous | |
| US EPA Classification (formulation) | - | - | ||
| UN Number | 2771 for active, variable with product, usually 3082 or 3267 | |||
| Waste disposal & packaging |
Spilled product is a hazardous waste and disposal must be at an approved manner Packaging Group III (minor danger) |
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| Language | Name |
| English | metam-sodium |
| French | metam |
| German | Metam |
| Danish | metam |
| Italian | metam |
| Spanish | metam |
| Greek | - |
| Slovenian | metam-natrij |
| Polish | metam |
| Swedish | - |
| Hungarian | - |
| Dutch | metam-natrium |
Record last updated: Sunday 27 May 2018
Contact: aeru@herts.ac.uk