Nomenclature

Type Herbicide
Common name Atrazine
Other name
Iupac name

6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine

Formulation type
Formulation TypeOptions
98%TC MSDS  
90%WG MSDS  
80%WP MSDS  
50%SC  
Chemical Abstracts Name

6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine

CAS RN 1912-24-9
EEC no 217-617-8
Official code
Development code

Physical Chemistry

M.F.

C8H14ClN5

Structure M
Mol. wt 215.7
Appearance

Colourless powder.

M.p.

175.8 ℃

B.p.

205.0 ℃/101 kPa

V.p.

3.85 ×10-2 mPa (25 ℃) (OECD 104)

F.p.
S.g./density

1.23 (22 ℃)

Solubility

In water 33 mg/l (pH 7, 22 ℃). In ethyl acetate 24, acetone 31, dichloromethane 28, ethanol 15, toluene 4.0, n-hexane 0.11, n-octanol 8.7 (all in g/l, 25 ℃).

Stability

Relatively stable in neutral, weakly acidic and weakly alkaline media. Rapidly hydrolysed to the hydroxy derivative in strong acids and alkalis, and at 70℃in neutral media; DT50 (pH 1) 9.5, (pH 5) 86, (pH 13) 5.0 d.

Henry
KowlogP
Pka

1.7, v. weak base

Applications

Biochemistry

Photosynthetic electron transport inhibitor at the photosystem II receptor site. Maize tolerance is attributed to rapid detoxification by glutathione transferases.

Mode of Action

Selective systemic herbicide, absorbed principally through the roots, but also through the foliage, with translocation acropetally in the xylem and accumulation in the apical meristems and leaves.

Uses

Pre- and post-emergence control of annual broad-leaved weeds and annual grasses in maize, sorghum, sugar cane, pineapples, chemical fallow, grassland, macadamia nuts, conifers, industrial weed control. In Europe, use is concentrated in maize and sorghum at ≤1.5 kg/ha. Used also in combinations with many other herbicides.

Phytotoxicity

Phytotoxic to many crops, including most vegetables, potatoes, soya beans, and peanuts.

Compatibility
General details

Mammalian Toxicology

Reviews
Oral

Acute oral LD50 for rats 1869-3090 mg tech./kg, mice >1332-3992 mg/kg.

Skin & Eye

Acute percutaneous LD50 for rats >3100 mg/kg. Mild skin irritant; non-irritating to eyes (rabbits). Skin sensitiser in guinea pigs, but not in humans.

Inhalation

LC50 (4 h) for rats >5.8 mg/l air. 

Noel

(2 y) for rats 10 mg/kg diet (0.5 mg/kg daily), for dogs 150 mg/kg diet (3.75 mg/kg daily), for mice 10 mg/kg diet (1.4 mg/kg daily).

ADI

0.005 mg/kg b.w.

Toxicity class

WHO (a.i.) U; EPA (formulation) III.

EC hazard

Ecotoxicology

Birds

Acute oral LD50 varies from 940 mg/kg for bobwhite quail to >2000 mg/kg for mallard ducks and 4237 mg/kg for adult Japanese quail. Dietary LC50 (8 d) for Japanese quail (chicks) >5000, (adults) >1000 mg/kg.

Fish

LC50 (96 h) for rainbow trout 4.5-11.0, bluegill sunfish 16, carp 76, catfish 7.6, guppies 4.3 mg/l.

Daphnia

LC50 (48 h) 6.9 mg/l.

Algae

EC50 (72 h) for Scenedesmus subspicatus 0.043 mg/l, (96 h) for Selenastrum capricornutum 0.13 mg/l.

Worms

LC50 (14 d) for Eisenia foetida 78 mg/kg soil. 

Environmental Fate

Plants

In tolerant plants, atrazine is readily metabolised to hydroxyatrazine and amino acid conjugates, with further decomposition of hydroxyatrazine by degradation of the side-chains and hydrolysis of the resulting amino acids on the ring, together with evolution of CO2. In sensitive plants, unaltered atrazine accumulates, leading to chlorosis and death.

Animals

In mammals, following oral administration, atrazine is rapidly and completely metabolised, primarily by oxidative dealkylation of the amino groups (R. Ikonen et al., Toxicol. Lett., 1988, 44, 109; Bull. Environ. Contam. Toxicol., 1989, 43, 199; Y. Deng et al., J. Agric. Food Chem., 1990, 38, 1411), and by reaction of the chlorine atom with endogenous thiols. Diaminochlorotriazine is the main primary metabolite, which readily conjugates with glutathione. More than 50% of the dose is eliminated in the urine and around 33% in the faeces within 24 h.

Soil/environment

Major metabolites under all conditions are desethylatrazine and hydroxyatrazine. Field DT50 16-77 d (median 41 d), the longer values being from cold or dry conditions. In natural waters, DT50 10-105 d (mean 55 d). DT50 under groundwater conditions 105->200 d, depending on test system (M. J. Wood et al. in: A Walker (Ed.), Pesticides in soils and water: current perspectives (BCPC Monograph 1991, 47, 175-182)). Kd 0.2-18 ml/g, Koc 39-173 ml/g; desalkylated metabolites had values similar to those of atrazine, while hydroxyatrazine was much more strongly adsorbed. 

Miscellaneous

Analysis

analysis by glc with FID (CIPAC Handbook, 1998, H, 33; FAO Specification (CP/61); AOAC Methods, 17th Ed., 971.08).

Packing