Maneb

Description

Maneb is a pesticide with fungicide properties and belongs to the carbamate (bis-dithiocarbamate) group. Sensitization occurs mainly in farmers and agricultural workers.

Chemical properties

Brown powder. Decomposes on heating. Partially soluble in water; soluble in chloroform.

Chemical properties

Maneb is a yellow powder or crystalline solid with a faint odor.

The Uses of Maneb

Maneb is a complex of manganese with the ethylene bis(dithiocarbamate) anionic ligand. Maneb is a foliate fungicide used to protect crops in agriculture. Maneb is also useful in creating a toxin-based animal (usually primates) model of Parkinson's disease.

The Uses of Maneb

Maneb is a contact fungicide that provides protection against a wide variety of fungal diseases (including leaf spots, blight, rust, downy mildew, scab, etc.) in field crops, fruits, vines, vegetables, ornamentals, potatoes, turf, berries and forestry.

Definition

ChEBI: A polymeric complex of manganese with the ethylene bis(dithiocarbamate) anionic ligand. An agrochemical fungicide, it is used to control a variety of diseases including blight, leaf spot, rust, downy mildew and scab.

General Description

Maneb is a yellow powder or crystalline solid. Maneb is denser than water. Contact may irritate skin, eyes and mucous membranes. Maneb may be toxic by ingestion. Likely to generate heat spontaneously upon exposure to air or water. May be sufficient to ignite the material. Maneb is used as a fungicide. Formulations of Maneb include mixing Maneb with many other chemicals such as sulfur, zinc oxide and others to desensitize it. This is done to make Maneb easer for application.

Air & Water Reactions

Highly flammable. Soluble in water. Maneb is likely to generate heat spontaneously, especially when wet. The heat may be sufficient to ignite the material. Thio and dithiocarbamates slowly decompose in aqueous solution to form carbon disulfide and methylamine or other amines. Such decompositions are accelerated by acids.

Reactivity Profile

The BPS Pesticide incident in Helena resulted in an explosion and death of three firemen. The burning of a 1,000 pound sack of Azinphos Methyl or the flashing of Maneb which was present on the facility may have caused the explosion.

Health Hazard

Fire will produce irritating, corrosive and/or toxic gases. Inhalation of decomposition products may cause severe injury or death. Contact with substance may cause severe burns to skin and eyes. Runoff from fire control may cause pollution.

Fire Hazard

Flammable/combustible material. May ignite on contact with moist air or moisture. May burn rapidly with flare-burning effect. Some react vigorously or explosively on contact with water. Some may decompose explosively when heated or involved in a fire. May re-ignite after fire is extinguished. Runoff may create fire or explosion hazard. Containers may explode when heated.

Agricultural Uses

Fungicide: Maneb is an ethylene(bis)dithiocarbamate fungicide used in the control of early and late blights on potatoes and tomatoes and many other diseases of fruits, vegetables, field crops, and ornamentals. Maneb controls a wider range of diseases than other fungicides. It is available as granular, wettable powder, flowable concentrate, and ready-to-use formulations. Maneb is widely used by itself and in combination with other pesticides on a variety of crops. Principal uses in California are for head and leaf lettuce, walnuts, almonds, onions, potatoes and broccoli.

Trade name

(The U.S. EPA lists more than 460 active and/ or canceled products containing maneb) AAMANGAN®; AKZO CHEMIE MANEB®; BASF-MANEB SPRITZPULVER®; BAVISTIN M®; COSMIC®; CHEM NEB®; CHLOROBLE M®; CLEANACRES®; CR 3029®; DELSENE M FLOWABLE®; DITHANE-22®; F 10®; FARMANEB®; IDA MANEB®; KASCADE®; KYPMAN 80®; LONOCOL M®; MANAM®; MANEB 80®; MANEBA®; MANEBE®; MANEBGAN®; MANESAN®; MANESAN®; MANEX®; MANOC®; MANZATE®; MANZATE D®; MANZATE MANEB FUNGICIDE®; MANZEB®; MANZI®; M-DIPHAR®; MULTI-W®; NEREB®; NESPOR®; NEWSPOR®; PLANTIFOG 160 M®; POLYRAM M®; REMASAN CHLOROBLE M®; RHODIANEHE®; SOPRANEBE®; SQUADRON AND QUADRANGLE MANEX®; SUPERMAN MANEB F®; SUP'R FLO®; TERSAN-LSR®; TRIMANGOL®; TRIMANOC®; TRITHAC®; TUBOTHANE®; UNICROP MANEB®; VANCIDE®; VANCIDE MANEB 80®; VASSGRO MANEX®; VITAVAX® Maneb

Contact allergens

Maneb is a pesticide with fungicide properties, belong-ing to the dithiocarbamate group. Sensitization occursmainly in farmers and agricultural workers.

Safety Profile

Moderately toxic by ingestion. Experimental teratogenic and reproductive effects. Questionable carcinogen with experimental carcinogenic and tumorigenic data. Mutation data reported. A fungcide. May ignite spontaneously in air. When heated to decomposition it emits highly toxic fumes of NOx and SOx. See also MANGANESE COMPOUNDS and CARBAMATES.

Potential Exposure

A potential danger to those involved in manufacture, formulation, and application of this broad spectrum dithiocarbamatefungicide. Some dithiocarbamates have been used as rubber components. DFG warns of danger of skin sensitization. The BPS Pesticide incident in West Helena, AK resulted in an explosion and death of three firemen. The burning of a 1000-lb sack of Azinphos Methyl or the flashing of Maneb which was present on the facility may have caused the explosion

First aid

If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, 1660 Maneb including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit.

Metabolic pathway

Maneb and other alkylenebis(dithi0carbamate) fungicides are degraded and metabolised via a common pathway. The primary degradation reaction of maneb in water, soils, plants and animals involves the initial dissociation of the metal complex and decomposition to numerous degradation products including ethylenethiourea (ETU) and ethyleneurea (EU) as major products (Scheme 1).

storage

Color Code—Red: Flammability Hazard: Store in a flammable liquid storage area or approved cabinet away from ignition sources and corrosive and reactive materials. Prior to working with this chemical you should be trained on its proper handling and storage. Maneb must be stored to avoid contact with water, since violent reactions occur. Store in tightly closed containers in a cool, well-ventilated area away from acids, moisture, heat, and oxidizing materials. Where possible, automatically transfer material from drums or other storage containers to process containers. A regulated, marked area should be established where this chemical is handled, used, or stored in compliance with OSHA Standard 1910.1045.

Shipping

UN2210 Maneb or Maneb preparations with not <60% maneb, Hazard Class: 4.3; Labels: 4.3-Dangerous when wet material, 4.2-Spontaneously combustible material. UN2968 Maneb stabilized or Maneb preparations, stabilized against self-heating, Hazard Class: 4.3; Labels: 4.3-Dangerous when wet material

Purification Methods

Crystallise this fungicide from EtOH. It is soluble in CHCl3. It is a skin irritant.[Beilstein 4 III 149, 4 IV 234.]

Degradation

Maneb (1) was rapidly hydrolysed in aqueous solutions (pH 5, 7 and 9) with DT₅₀ values of <24 hours (PM). Dithiocarbamate compounds decompose in aqueous solutions following a common pathway that involves the dissociation of the metal complex, and rapid rearrangement reactions to yield 5,6-dihydro-3H-imidazo[2,1-c]-1,2,4-dithiazole-3-thione (2) which is further degraded slowly to ETU (3). ETU in aqueous solution was ultimately converted into 2-imidazoline (4) and EU (5) (kaars Sijpesteijn and Vonk, 1974).

Incompatibilities

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides, water. Dithiocarbamate esters are combustible. They react violently with powerful oxidizers such as calcium hypochlorite. Poisonous gases are generated by the thermal decomposition of Dithiocarbamate compounds, including carbon disulfide, oxides of sulfur, oxides of nitrogen, hydrogen sulfide, ammonia, and methylamine. Thio and dithiocarbamates slowly decompose in aqueous solution to form carbon disulfide and methylamine or other amines. Such decompositions are accelerated by acids. Flammable gases are generated by the combination of dithiocarbamate with aldehydes, nitrides, and hydrides. Dithiocarbamate are incompatible with acids, peroxides, and acid halides.

Waste Disposal

Generators of waste containing this contaminant (≥100 kg/mo) must conform to EPA regulations governing storage, transportation, treatment, and waste disposal. Maneb is unstable to moisture and is hydrolyzed by acids and hot water. It decomposes at about 100℃ but may spontaneously decompose vigorously when stored in bulk. Incineration is the preferred disposal means. In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office