| Description | Metam sodium is a crystalline material with an unpleasantodor of sulfur compounds. It reacts in water to generatemethyl isothiocyanate, which is the active material. It isapplied as a freshly diluted solution in water. |
| Chemical Properties | White, crystalline solid. Readily solublein water; moderately soluble in alcohol; stable inconcentrated aqueous solution but decomposes indilute aqueous solution; unstable in moist soil. |
| Chemical Properties | A yellow to nearly clear yellow-green solution. Also described as a colorless to white crystalline solid.Unpleasant sulfur-amine odor, similar to that of carbondisulfide |
| Uses | Fungicide, nematocide, weed killer, insecticide,soil fumigant. |
| Uses | Metam-sodium is a generator of methyl isothiocyanate. It is a soilsterilant applied prior to planting and controls soil fungi, nematodes,weed seeds and soil dwelling insects. |
| Uses | Metam Sodium is useful as an environmental-friendly and sustainable electrocatalyst for oxygen reduction reactions. |
| Definition | ChEBI: Metam-sodium is an organic sodium salt and an organosulfur insecticide. It has a role as a proherbicide, a proinsecticide, a profungicide and a pronematicide. It contains a metam(1-). |
| General Description | A yellow to light yellow-green aqueous solution with an odor of amine and sulfur that varies in intensity. Boiling point 230°F. Metham sodium has a specific gravity of 1.162. Metham sodium will decompose upon dilution to carbon disulfide, monomethylamine, methylisothiocyanate, and hydrogen sulfide. The decomposition products are flammable and toxic. The acute symptoms of exposure to metam sodium are excessive salivation, sweating, fatigue, weakness, nausea, headache, dizziness, eye and respiratory tract irritation, and skin irritation in the form of rashes. The spillage of a rail car tanker of metal sodium into the Sacramento River caused a major fish kill (over a million trout) along several miles of that river. |
| Air & Water Reactions | Slow reaction upon dilution produces toxic gases hydrogen sulfide and methylisothiocyanate. This reaction is accelerated by the addition of acid. |
| Reactivity Profile | METAM SODIUM is a dithiocarbamate. Flammable gases are generated by the combination of thiocarbamates and dithiocarbamates with aldehydes, nitrides, and hydrides. Thiocarbamates and dithiocarbamates are incompatible with acids, peroxides, and acid halides. |
| Hazard | Irritant to tissue, toxic to plants and vege-tation. |
| Health Hazard | TOXIC; inhalation, ingestion or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution. |
| Fire Hazard | Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. |
| Flammability and Explosibility | Not classified |
| Agricultural Uses | Fungicide; Nematicide, Herbicide, Soil fumi-gant, Algaecide: A general soil biocide that is used to control weeds, weed seeds, roots, tubers, rhizomes, insects, nematodes and soil inhabiting fungi on all food and non-food crops. Also used as a pre-planting fumigant in seed beds, vine crops, fruit trees, row crops, flowers and ornamentals. Environmental friendly; it breaks down after two weeks into carbon dioxide, water, and sodium and sulfur in small amounts. A U.S. EPA restricted Use Pesticide (RUP). Registered for use in some EU countries. |
| Trade name | A7-VAPAM®; BASAMID-FLUID®; BUSAN®; CHAP-FUME®; DISCOVERY®; HERBATIM (dihydrate)®; KARBATION®; KARBATION (di-hydrate)®; MAPOSOL®; MAPOSOL (dihydrate)®; METACIDE®; METAM (dihydrate)®; METAM-FLUID BASF®; METHAM DIHYDRATE (dihydrate)®; MONAM (dihydrate)®; N-869®; N 869 (dihydrate)®; NEMATIN®; SECTAGON®; SISTAN®; SMDC (di-hydrate)®; SOLASAN 500®; SOLESAN 500®; SOMETAM®; TRAPEX®; TRIMATON (dihydrate)®; TRIMATRON®; UCETAM®; VAPAM®; VAPAM (di-hydrate)®; VAPOROOTER (dihydrate)®; VDM®; VPM (dihydrate)®; VPM® Fungicide; VPN®; WOODFUME VAPAM® |
| Contact allergens | Metham-Na is a fungicide nematocide of the dithiocarbamate group. Sensitization occurs among agricultural workers. |
| Potential Exposure | A dithiocarbamate fungicide, nematicide, herbicide, soil fumigant, and algaecide A general soilbiocide that is used to control weeds, weed seeds, roots,tubers, rhizomes, insects, nematodes and soil inhabitingfungi on all food and nonfood crops. Also used as a preplanting fumigant in seed beds, vine crops, fruit trees, rowcrops, flowers and ornamentals. Environmental friendly; itbreaks down after two weeks into carbon dioxide, water,and sodium and sulfur in small amounts. A United StatesEnvironmental Protection Agency Restricted Use Pesticide(RUP). |
| Metabolic pathway | Metam-sodium is a water soluble propesticide that decomposes to generatethe highly volatile and fungitoxic methyl isothiocyanate. The pathwaysof metabolism of methyl isothiocyanate are described under its ownentry. |
| Shipping | UN3267 Corrosive liquid, basic, organic, n.o.s.,Hazard class: 8; Labels: 8-Corrosive material, TechnicalName Required. UN2771 Dithiocarbamate andThiocarbamate pesticides, solid, toxic, Hazard Class: 6.1;Labels: 6.1-Poisonous materials |
| Degradation | Metam-sodium can be stable in concentrated aqueous solution for severalweeks but is unstable when diluted. Decomposition is promoted by acidsand salts of heavy metals. DT50 values for hydrolysis of metam-sodiumwere 23.8, 180 and 45.6 hours at pH 5, 7 and 9 (25 °C), respectively. It issensitive to light and solutions exposed to sunlight had a DT50 value of 1.6hours (pH 7, 25 °C) (PM). In aqueous solution at high pH (9.5), metamsodiumwas oxidatively degraded to form methyl isothiocyanate (2) andelemental sulfur. At lower pH it was degraded non-oxidatively, affordingcarbon disulfide, hydrogen sulfide, methy lamine, methyl isothiocyanate(2) and N,N'-dimethylthiuram disulfide (3). It is noteworthy that methylamineand carbon disulfide can react to yield methyl isothiocyanate (2)that can in turn react with metam to produce N,N'-dimethylthiuramdisulfide (3). Methyl isothiocyanate (2) can react with methylamineor hydrogen sulfide, giving dimethylthiourea (4) (Turner and Corden,1963). |
| Incompatibilities | Slow reaction upon dilution in waterreleasing toxic gases of hydrogen sulfide and methyl isothiocyanate. This reaction is accelerated by the addition ofacid. May liberate toxic gas when in contact with acids.Combustible; vapors when heated or dust from dry materialmay form explosive mixture in air. Dithiocarbamate estersare combustible. They react violently with powerful oxidizers such as calcium hypochlorite. Poisonous gases are generated by the thermal decomposition of Dithiocarbamatecompounds, including carbon disulfide, oxides of sulfur,oxides of nitrogen, hydrogen sulfide, ammonia, and methylamine. Thio and dithiocarbamates slowly decompose inaqueous solution to form carbon disulfide and methylamineor other amines. Such decompositions are accelerated byacids. Flammable gases are generated by the combinationof dithiocarbamate with aldehydes, nitrides, and hydrides.Dithiocarbamate are incompatible with acids, peroxides,and acid halides. Corrosive to iron, copper brass and zincmetals, especially in the presence of moisture. Heat alkalies(lime), moisture can cause decomposition. Degradation produces ethylene thiourea. |
| Waste Disposal | Do not discharge into drainsor sewers. Dispose of waste material as hazardous wasteusing a licensed disposal contractor to an approved landfill. Consult with environmental regulatory agencies forguidance on acceptable disposal practices. Generators ofwaste containing this contaminant (≥100 kg/mo) mustconform to EPA regulations governing storage, transportation, treatment, and waste disposal. A potential candidate for liquid injection incineration at a temperaturerange of 650 to 1600C and a residence time 0.1 to2 seconds. Also, a potential candidate for rotary kilnincineration at a temperature range of 820 to 1600C andresidence times of seconds for liquids and gases,and hours for solids. |
