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DESIGNATIONS
CAS No.: 63-25-2
Registry name: Carbaryl
Chemical name: 1-Naphthyl-methylcarbamate
Synonyms, Trade names: 1-Naphthalenyl-methylcarbamate, Sevin, Atoxan, Caprolin, Compound 7744, Gamonil, Panam, Sevidol and many others
Chemical name (German): Carbaryl, 1-Naphthyl-N-methylcarbamat
Chemical name (French): Carbaryl, 1-naphthyl méthylcarbamate
Appearance: colourless, crystalline solid (pure substance)
BASIC CHEMICAL AND PHYSICAL DATA
| Empirical formula: | C12H11NO2 |
| Rel. molecular mass: | 201.23 g |
| Density: | 1.232 g/cm3 |
| Boiling point: | not distillable |
| Melting point: | 142°C |
| Vapour pressure: | <0.7 Pa at 25°C |
| Solvolysis/solubility: | in water: < 1g/l in acetone: 200-300 g/l; in cyclohexanone: 200-250 g/l; in ether: 200 g/l; in isopropanol: 100 g/l; in xylene: 100 g/l |
ORIGIN AND USE
Usage:
Carbaryl is a contact insecticide with a long lasting effect. It
is used as a spraying powder (50% + 12.5% Tetradifon; 37.5 % +
11.2 % Dioxathion) in winegrowing e.g. against mites and in
combination with lindane against potato-bugs.
Origin/derivation:
There are no natural sources. Carbaryl is obtained from
1-naphthol, either by reaction with methylisocyanate or by
treatment with phosgene and subsequent reaction of the resulting
chloroformate with methylamine.
Production figures:
World production of carbaryl:
| 25,000 t | (1971) | (ULLMANN, 1989) |
| 1,000-1,500 t | (1989) | (KOCH, 1989) |
Toxicity
| Mammals: | ||
| Rat | LD50 400-850 mg/kg, oral | acc. PERKOW, 1994 |
| LD50 >4000 mg/kg, dermal | acc. PERKOW, 1994 | |
| NOEC 2,000mg/kg feed, (2a) | acc. PERKOW, 1994 | |
| Rabbit | LD50 710 mg/kg, oral | acc. PERKOW, 1994 |
| LD50 >2,000 mg/kg, dermal | acc. PERKOW, 1994 | |
| Guinea pig | LD50 280 mg/kg, oral | acc. KOCH, 1989 |
| Aquatic organisms: | ||
| Fish (various) | LC50 1.75-4.25 mg/l (24 h) | acc. PERKOW, 1994 |
| LC50 0.1-13 mg/l (24 h) | acc. KOCH, 1989 | |
| LC50 2-20 mg/l (24 h) | acc. VERSCHUEREN, 1983 | |
| Goldfish | LC50 28 mg/l (24 h) | acc. PERKOW, 1994 |
| LC50 13.2 mg/l (96 h) | acc. VERSCHUEREN, 1983 | |
| Insects: | ||
| Bee | LD50 1.3 µg/bee, contact | acc. PERKOW, 1994 |
| LD50 0.14 µg/bee, oral | acc. PERKOW, 1994 | |
Characteristic effects:
Humans/mammals: Carbaryl belongs to the group of the carbamates which are quickly degraded and not accumulated in humans. Poisoning may be due to oral intake or resorption via the skin. The physiological effects result from the (reversible) inhibition of the enzyme acetylcholinesterase causing convulsions and other neuromuscular manifestations. These effects take place very quickly but last only for a short time. Carbaryl is readily hydrolysed forming 1-naphthol which is excreted.
ENVIRONMENTAL BEHAVIOUR
Soil:
Due to its solubility in water, carbaryl is expected to be
very mobile in soil. Thus, there is hardly any accumulation in
this medium. Generally, the persistence of carbamate insecticides
in soil is considered to be low to moderate (one to four months)
due to their mobility and biodegradability [ULLMANN, 1989].
Water:
In aquatic systems hydrolysis takes place at pH>7 forming
1-naphthol and methylamine. Although degradation is relatively
fast the possibility of migration of the substance into the
groundwater has to be taken into account [KOCH, 1989]. In
Germany, the substance is classified in water hazard class 2.
ENVIRONMENTAL STANDARDS
| Medium/ acceptor |
Sector | Country/organ. | Status | Value | Cat. | Remarks | Source |
| Water: | Drinkw | D | L |
0.1 µg/l | single substance | acc. KOCH, 1989 | |
| Drinkw | SU | L |
100 µg/l | acc. KOCH, 1989 | |||
| Groundw | NL | L |
0.1 µg/l | Intervention | acc. TERRA TECH, 6/94 | ||
| Soil: | NL | L |
5 mg/kg | Intervention | acc. TERRA TECH, 6/94 | ||
| Air: | Workp | D | L |
5 mg/m3 | MAK | Skin | acc. AUER TECHNIKUM, 1988 |
| Workp | USA | (L) |
5 mg/m3 | TWA | acc. AUER TECHNIKUM, 1988 | ||
| Workp | SU | (L) |
1 mg/m3 | acc. AUER TECHNIKUM, 1988 | |||
| Emiss. | D | L |
5 mg/m3 | mass flow > 25 g/h | acc. TA Luft, 1986 | ||
| Foodstuffs: | WHO | G |
0.01 mg/kg/d | ADI | acc. KOCH, 1989 | ||
| Kiwi | D | L |
10 mg/kg | acc. PERKOW, 1994 | |||
| Apple, apricot, pear, peach, plum, grape, cabbage, salad | D | L |
3 mg/kg | acc. PERKOW, 1994 | |||
| Remaining fruits and vegetable, rice | D | L |
1 mg/kg | acc. PERKOW, 1994 | |||
| Remaining grain | D | L |
0.5 mg/kg | acc. PERKOW, 1994 | |||
| Remaining vegetable food | D | L |
0.1 mg/kg | acc. PERKOW, 1994 | |||
| acc. PERKOW, 1994 | |||||||
Note:
In Germany , the use of carbaryl is prohibited (1994)
Assessment/comments
Carbaryl features a relatively low toxicity for humans, no tendency towards bioaccumulation and a low persistence in soil due to its biodegradability. On the other hand, it has a toxic effect on bees and aquatic organisms even in small quantities. Thus, its use should be reduced as far as possible.