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DESIGNATIONS
CAS No.: 534-52-1
Systematic name: Dinitro-o-cresol
Chemical name: 2-Methyl-4,6-dinitrophenol
Synonyms, Trade names: 4,6-Dinitro-o-cresol, DNOC, DNC, Detal, Etzel, fruit-tree carboline
Chemical name (German): Dinitro-o-kresol, 2-Methyl-4,6-dinitrophenol
Chemical name (French): Dinitro-o-crésol
Appearance: yellow powder or crystals with bitter taste
BASIC CHEMICOPHYSICAL DATA
| Empirical formula: | C7H6N2O5 |
| Rel. molecular mass: | 198.14 g |
| Boiling point: | (decomposition) |
| Melting point: | 86-86.9°C |
| Vapour pressure: | 6.5 x 10-3 Pa at 25°C |
| Flash point: | limited combustibility |
| Solvolysis/solubility: | in water: slightly soluble 125 ppm (at
25°C); in acetone: 100.6 g/100 g; in ethanol: 4.3 g/100 g; in benzene: 37.5 g/100 g; in chloroform: 37.2 g/100 g; soluble in diethylether, methanol, petroleum ether, carbon tetrachloride |
ORIGIN AND USE
Usage:
DNOC is a selective herbicide used in the cultivation of grain,
hops, vines and fruit (insecticide, acaricide, with fungicidal
secondary effects).
Origin/derivation:
DNOC is only produced synthetically. Commercially available
preparations contain formulations of the alkali, ammonia, or
amine salts of DNOC which are normally highly soluble in water.
Toxicity
| Humans: | LD 0.35-3.0 g | acc. DFG, 1986 |
| Mammals: | ||
| Rat: | LD50 25-85 mg/kg, oral | acc. DFG, 1986 |
| LD50 28.5 mg/kg, intraperitoneal | acc. DFG, 1986 | |
| LD50 23.1-26.1 mg/kg, subcutaneous | acc. DFG, 1986 | |
| Mouse: | LD5020.0 mg/kg, oral | acc. DFG, 1986 |
| LD50 21.5-27.3 mg/kg, subcutaneous | acc. DFG, 1986 | |
| LD50 1,000 mg/kg, cutaneous | acc. DFG, 1986 | |
| LD50 24-26 mg/kg, intraperitoneal | acc. DFG, 1986 | |
| Guinea pig: | LD100 500 mg/kg, cutaneous | acc. DFG, 1986 |
| Dog: | LD50 15 mg/kg, intravenous | acc. DFG, 1986 |
| LD50 10-23.5 mg/kg, intraperitoneal | acc. DFG, 1986 | |
| Aquatic organisms: | ||
| American minnow: | 1.5-2 mg/l lethal (6 h) | acc. DVGW, 1988 |
| Stickleback: | 3 mg/l lethal | acc. DVGW, 1988 |
| Water flea: | EC50 0.013 mg/l | acc. DVGW, 1988 |
| Blue algae: | EC10 0.15 mg/l | acc. DVGW, 1988 |
| Green algae: | EC10 13 mg/l | acc. DVGW, 1988 |
Characteristic effects:
Humans/mammals: DNOC is a powerful, cumulative-action poison which can even prove fatal. Absorption is primarily by way of the lungs, but also via the gastro-intestinal tract and through the skin. Assimilated DNOC is only slowly excreted.
The first symptoms of poisoning are an increase in body temperature (high ambient temperatures enhance the severity), sweating, rapid breathing and accelerated pulse, extreme thirst, painful colics, diarrhoea and nausea. Typical symptoms of the effects on the central nervous system are euphoria to be followed by dizziness, possible collapse, anxiety, unrest, disorientation, loss of consciousness and terminal spasms.
Chronic poisoning takes the form of headaches, fatigue and noticeable weight loss. There is also damage to the heart, liver and kidneys. Liver damage is encountered primarily in the case of oral intake.
Plants: The effect on plants is based on the separation of cell respiration and oxidative phosphorylation.
ENVIRONMENTAL BEHAVIOUR
Water:
Despite the fact that the solubility in water is extremely
low, surface water may be polluted by the elution of soil treated
with DNOC. It is more harmful to plankton and microorganisms than
to fish. Threshold concentration for water fleas is 3 mg/l,
for mosquitoes 500 mg/l.
The toxicity of DNOC solutions is highly dependent on the pH. Acid solutions are more toxic than alkaline solutions (DFG, 1986).
Soil:
DNOC is highly mobile in soil and is only subject to slow
microbial degradation. Most soil organisms are not adversely
affected by DNOC; CO2 production is not impaired; the
effect on microarthropodes (e.g. mites) and earth worms is
however lethal.
Degradation, decomposition products:
Numerous metabolites have been found in the organism, some of
which have a detoxifying effect, whereas others are even more
toxic than DNOC itself (e.g. 6-amino-4-nitro-o-cresol or
4,6-diamino-o-cresol). There are no data available metabolites in
plants and soil.
DNOC can be traced in soil for a period of up to 14 weeks (acc. DFG, 1986).
Food chain:
There is evidence of residues in parts of plants.
ENVIRONMENTAL STANDARDS
| Medium/ acceptor | Sector | Country/ organ. | Status |
Value | Cat. | Remarks | Source |
| Water: | Surface | EC | (L) |
0.001 mg/l | All pesticides1) | acc. DVGW, 1988 | |
| Surface | EC | (L) |
0.0025 mg/l | All pesticides2) | acc. DVGW, 1988 | ||
| Surface | EC | (L) |
0.005 mg/l | All pesticides3) | acc. DVGW, 1988 | ||
| Drinkw | EC | (L) |
0.1 µg/l | acc. DVGW, 1988 | |||
| Drinkw | FRG | L |
0.1 µg/l | acc. DVGW, 1988 | |||
| Air: | Workp | FRG | L |
0.2 mg/m3 | MAK | DFG, 1989 | |
| Workp | SU | (L) |
0.05 mg/m3 | acc. KETTNER, 1979 | |||
| Workp | USA | (L) |
0.2 mg/m3 | TWA | ACGIH, 1986 | ||
| Foodstuffs: | FRG | (G) |
0.01 ng/kg.d | Provisional DTA | acc. DFG, 1986 |
Notes:
DNOC cannot be used as an insecticide in the Federal Republic of Germany in water catchment areas. Its use as a herbicide is banned in water protection zones I and II. Use in the immediate vicinity of stretches of water is forbidden.
1) Mandatory value for simple physical treatment and sterilisation
2) Mandatory value for normal physical and chemical treatment and sterilisation
3) Mandatory value for physical and refined chemical treatment, oxidation, adsorption and sterilisation
Assessment/comments
DNOC has an extremely high acute toxicity and represents a particular hazard. The substance is readily absorbed by the lungs and through the skin. Thus protective measures are required during application. The use of DNOC near large areas of water should particularly be avoided.