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The information in this profile may be out-of-date. It was last revised in 1996. EXTOXNET no longer updates this information, but it may be useful as a reference or resource.

Please visit the National Pesticide Information Center (NPIC) to find updated pesticide fact sheets. If you don't find a fact sheet related to your question, feel free to call 1-800-858-7378. NPIC is open five days a week from 8:00am to 12:00pm Pacific Time.

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E X T O X N E T

Extension Toxicology Network

Pesticide Information Profiles

A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Oregon State University, the University of Idaho, and the University of California at Davis and the Institute for Environmental Toxicology, Michigan State University. Major support and funding was provided by the USDA/Extension Service/National Agricultural Pesticide Impact Assessment Program.

EXTOXNET primary files maintained and archived at Oregon State University

Revised June 1996

Cyanazine

Trade and Other Names: Trade names include Bladex, DW3418, Fortrol, Match, and Payze. Cyanazine may be used in combination with other herbicides.

Regulatory Status: Cyanazine is classified by the EPA as a Restricted Use Pesticide (RUP) because of its teratogenicity and because it has been found in groundwater. Restricted Use Pesticides may be purchased and used only by certified applicators. Classified as toxicity class II - moderately toxic, products containing cyanazine bear the Signal Word WARNING.

Chemical Class: triazine

Introduction: Cyanazine, a triazine, is used as a pre- and post-emergent herbicide to control annual grasses and broadleaf weeds. It is used mostly on corn, some on cotton, and less than 1% on grain sorghum and wheat fallow. Nearly 2.25 million acres of land were treated with cyanazine in the U.S. The compound is formulated as a wettable powder, a flowable suspension, or as granules.

Formulation: The compound is formulated as a wettable powder, a flowable suspension, or as granules.

Toxicological Effects:

• Acute toxicity: Cyanazine is moderately toxic to mammals. The oral LD50 in rats ranges from 182 mg/kg to 332 mg/kg, with females experiencing higher toxicities (lower LD50). The oral LD50 is 380 mg/kg in mice and 141 mg/kg in rabbits [3,6,15]. Poisoned animals have labored breathing and blood in their saliva [5,6,15]. Cyanazine may also cause inactivity and depression in laboratory animals. The dermal LD50 in rabbits treated with technical cyanazine is greater than 2000 mg/kg, and the dermal LD50 in rats is greater than 1200 mg/kg [3,6,15]. Cyanazine is only slightly toxic through inhalation. It is a mild eye irritant.
• Chronic toxicity: Several long-term feeding studies in rats and mice at doses up to 225 mg/kg/day showed that cyanazine decreases body weight gain and increases liver weights [11].
• Reproductive effects: Cyanazine caused decreases in maternal body weight gain in rats at doses of 30 mg/kg/day [27]. It also caused maternal toxicity and decreased fetal viability in rabbits at doses of 2 mg/kg/day [27]. It appears that reproductive effects are not likely in humans at expected exposure levels.
• Teratogenic effects: Cyanazine can cause a variety of birth defects in animals over a wide range of doses. In a long-term study of rats fed cyanazine, moderate doses resulted in increased brain weights and decreased kidney weights in third generation offspring [11]. Toxic effects on the fetus were also observed in experiments on rabbits using comparable doses. Female rats fed cyanazine through a stomach tube during pregnancy ate less food and their fetuses had incomplete bone development. At the higher doses, fetuses showed cleft palates and the absence of, or underdeveloped eyeballs [11]. Other birth defects observed in animals include abnormalities in diaphragm development and changes in the brain. Birth defects have been observed in the offspring of pregnant rats fed cyanazine during gestation at doses as low as 1 mg/kg/day.
• Mutagenic effects: Cyanazine is not mutagenic [3].
• Carcinogenic effects: Cyanazine does not appear to be carcinogenic. A study evaluated the carcinogenicity of the compound in mice and found, up to the maximum dose tested (50 mg/kg/day), no evidence of cancer in the animals [3,11].
• Organ toxicity: Cyanazine in animals causes depression of the central nervous system.

• Fate in humans and animals: Low doses of cyanazine fed to rats, dogs, and cows are rapidly absorbed from the gastrointestinal tract. In a study on rats and dogs, much of the cyanazine ingested was eliminated from animals within 4 days [11]. There is some tendency for cyanazine to accumulate in the brain, liver, kidney, muscle, and fat [11]. Cows fed very low amounts of cyanazine eliminated up to 88% of the cyanazine in urine and feces within 21 days. The concentration in cows' milk was very low, at 0.022 ppm [11].

Ecological Effects:

• Effects on birds: Cyanazine is slightly to moderately toxic in birds. The oral LD50 in mallards is greater than 2000 mg/kg, and in bobwhite quail is 400 mg/kg [15,16].
• Effects on aquatic organisms: Cyanazine is slightly to moderately toxic to fish and aquatic invertebrates [15,16]. The LC50 (96-hour) for cyanazine in harlequin fish is 7.5 mg/L, and 18 mg/L in sheepshead minnow [16].
• Effects on other organisms: Cyanazine is nontoxic to bees [27].

Environmental Fate:

• Breakdown in soil and groundwater: Cyanazine has a low to moderate persistence in soil. It quickly degrades in many soil types mostly due to the action of microbes [28]. Cyanazine has a half-life of 2 to 4 weeks in an air-dried sandy clay loam, 7 to 10 weeks in a sandy loam soil, 10 to 14 weeks in a clay soil, and 9 weeks in a fresh sandy clay soil. It undergoes slight decomposition by sunlight. The rate of evaporation of cyanazine from soil is very slow [12]. Cyanazine can be transported in runoff, sediment, and water, and it can leach through the soil to the groundwater. Cyanazine has been found in numerous groundwater samples at very low concentrations (0.001-0.08 mg/L) [6]. A groundwater advisory statement on cyanazine product labels is required.
• Breakdown in water: Cyanazine is stable to the chemical action of water (hydrolysis) and to the action of sunlight (photolysis) [28].
• Breakdown in vegetation: Cyanazine is absorbed by the roots and is translocated up the plant into the leaves. It works by inhibiting photosynthesis [15].

Physical Properties:

• Appearance: Cyanazine is a member of the s-triazine chemical family. This odorless, white crystalline solid is incompatible with metals [6].
• Chemical Name: 2-(4-chloro-6-ethylamino-1,3,5-triazin-2-ylamino)-2-methylpropionitrile [6]
• CAS Number: 21725-46-2
• Molecular Weight: 240.70
• Water Solubility: 171 mg/L @ 25 C [6]
• Solubility in Other Solvents: benzene v.s.; chloroform v.s.; alcohol v.s.; hexane v.s.; xylene s.s.; ethanol s.s. [6]
• Melting Point: 167 C [6]
• Vapor Pressure: 0.0002 mPa @ 20 C [6]
• Partition Coefficient: 2.22 [16]
• Adsorption Coefficient: 190 [20]

Exposure Guidelines:

• ADI: Not Available
• MCL: Not Available
• RfD: Not Available
• PEL: Not Available
• HA: 0.01 mg/L (lifetime) [11]
• TLV: Not Available

Basic Manufacturer:

DuPont Agricultural Products
Walker's Mill, Barley Mill Plaza
P.O. Box 80038
Wilmington , DE 19880-0038

• Phone: 800-441-7515
• Emergency: 800-441-3637
  

References:

References for the information in this PIP can be found in Reference List Number 8

DISCLAIMER: The information in this profile does not in any way replace or supersede the information on the pesticide product labeling or other regulatory requirements. Please refer to the pesticide product labeling.