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The information in this profile may be out-of-date.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

Propazine

Trade and Other Names: Trade names include G-30028, Geigy 30028, Gesamil, Milocep, Milogard, Milo-Pro, Plantulin, Primatol P, Propazin, Propinex, and Prozinex.

Regulatory Status: Propazine is classified as a slightly toxic compound in EPA toxicity class III and as a General Use Pesticide (GUP). Labels for products containing propazine must bear the Signal Word CAUTION.

Chemical Class: triazine

Introduction: Propazine is an herbicide used for control of broadleaf weeds and annual grasses in sweet sorghum. It is applied as a spray at the time of planting or immediately following planting, but prior to weed or sorghum emergence. It is also used as a postemergence selective herbicide on carrots, celery and fennel. Propazine is available in wettable powder, liquid, and water dispersible granular formulations.

Formulation: Propazine is available in wettable powder, liquid, and water dispersible granular formulations.

Toxicological Effects:

• Acute toxicity: Propazine is slightly toxic by ingestion with reported oral LD50 values of 3840 mg/kg to greater than 7000 mg/kg in rats, 3180 mg/kg in mice, and 1200 mg/kg in guinea pigs [6,15]. It is slightly toxic dermally; slight irritation was noted after propazine was applied to the skin of rabbits [9]. Its dermal LD50 in rats is 10,200 mg/kg, and in rabbits is greater than 2000 mg/kg [9]. Eye applications of 400 mg caused mild eye irritation in these animals [42]. The inhalation LC50 is greater than 2.04 mg/L [6], indicating slight toxicity by this route as well. Symptoms of exposure may include dizziness, lethargy, muscular weakness, runny nose, emaciation, diarrhea, labored breathing, and irregular breathing [43]. It may be mildly irritating to the skin, eyes, and upper respiratory tract. Contact dermatitis has been reported among workers manufacturing propazine [3].
• Chronic toxicity: When given daily to rabbits for 1 to 4 months, oral doses of 500 mg/kg/day propazine were reported to cause a type of anemia [3]. No gross signs of toxicity or pathologic changes were evident in rats that received daily doses of 250 mg/kg of propazine for 130 consecutive days [15]. No clinical or physical toxic symptoms were observed in beagle dogs fed 1.25, 5, or 25 mg/kg/day of a propazine formulation in 90-day feeding studies [3].
• Reproductive effects: There was an increase in the number of deaths of newborns born to female rats that were given 5 mg/kg/day of propazine during 18 days of pregnancy [44]. In a three-generation study with rats fed 0.15, 5, or 50 mg/kg/day, no effects on fertility, length of pregnancy, pup viability or pup survival were observed [45]. The data regarding reproductive effects are inconclusive.
• Teratogenic effects: Maternal doses of 500 mg/kg/day resulted in maternal toxicity and developmental toxicity expressed as increased incidence of extra ribs, incomplete bone formation, and decreased fetal body weights in rats [45]. At 50 mg/kg/day, pup body weights on day 21 of lactation were reduced, and there were pathological changes in organ weights in the second and third generation [45]. These data suggest that teratogenic effects due to propazine are not likely unless the level of exposure is high.
• Mutagenic effects: Propazine has shown no mutagenic effects in tests conducted on human and rat liver cells and in live hamsters [9].
• Carcinogenic effects: No evidence of increased tumor frequency was detected in a 2-year study in mice fed doses up to 450 mg/kg/day of propazine [9]. When rats were fed 0.15, 5, or 50 mg/kg of propazine each day for 2 years, there was an increase in the incidence of mammary gland tumors at the highest dose level [9]. The data regarding carcinogenicity are inconclusive.
• Organ toxicity: Liver damage is one of the suspected effects of propazine [42]. The functioning of certain liver processes was decreased in rats which were given 2500 mg/kg/day propazine [9].

• Fate in humans and animals: Propazine is readily absorbed and metabolized in the body [33]. At 72 hours after administration of single oral doses of propazine to rats, 66% of the dose was excreted in the urine and 23% was excreted in the feces [33]. This study also indicated that 77% of the dose was absorbed into the bloodstream from the gastrointestinal tract. At 8 days after the dosing, propazine or its metabolites were detected in the rats' lungs, spleen, heart, kidneys, and brain [9].

Ecological Effects:

• Effects on birds: Propazine is practically nontoxic to slightly toxic to birds; the 8-day dietary LC50 is greater than 10,000 ppm in both bobwhite quail and mallard ducks [6].
• Effects on aquatic organisms: Propazine is slightly toxic to fish; the 96-hour LC50 is 18 mg/L in rainbow trout, greater than 100 mg/L in bluegill sunfish, and greater than 32 mg/L in goldfish [6].
• Effects on other organisms: Propazine is practically nontoxic to bees [6].

Environmental Fate:

• Breakdown in soil and groundwater: Propazine is highly persistent in the soil environment, with reported field half-lives ranging from 35 to 231 days [20]. It is broken down mainly by microbial action, and therefore will persist longer in dry, cold conditions or other conditions which inhibit microbial activity [15]. Photolysis and volatilization are not important factors in propazine degradation [15]. It is slightly soluble in water and is poorly bound by soils. One study found propazine to be mobile in sandy loam, loam, and clay loam soils. It was very mobile in loamy sand [45]. It may contaminate groundwater, especially in areas with low organic matter and clay content, high rainfall, or irrigation rates, porous soils, and with excessive application. In 15 out of 906 groundwater samples collected from eight states, propazine was detectable. The maximum concentration found in any sample was 0.013 mg/L [45].
• Breakdown in water: Propazine is resistant to breakdown by hydrolysis. After 28 days at pH 5, 60% of applied propazine remained unhydrolyzed; at pH 7, 92% remained; and at pH 9, 100% remained [4]. It has been found in 33 out of 1097 surface water samples at levels below 0.3 mg/L [9,45].
• Breakdown in vegetation: Propazine is absorbed principally through plant roots, and translocated to growing shoots (meristems) and leaves of plants [15]. Propazine accumulates and inhibits cell reproduction of the growth regions (meristems) in those plants that are unable to readily metabolize it, but in tolerant species it is readily transformed via hydrolysis and ring cleavage [6].

Physical Properties:

• Appearance: Propazine is a colorless crystalline solid under normal circumstances [6].
• Chemical Name: 6-chloro-N2,N4-di-isporopyl-1,3,5-triazine-2,4-diyldiamine [6]
• CAS Number: 139-40-2
• Molecular Weight: 229.70
• Water Solubility: 5 mg/L @ 20 C [6]
• Solubility in Other Solvents: difficult to dissolve in organic solvents: in benzene, toluene, carbon tetrachloride, and diethyl ether [6]
• Melting Point: 212-214 C [6]
• Vapor Pressure: 0.004 mPa @ 20 C [6]
• Partition Coefficient: Not Available
• Adsorption Coefficient: 154 [20]

Exposure Guidelines:

• ADI: Not Available
• MCL: Not Available
• RfD: 0.02 mg/kg/day [26]
• PEL: Not Available
• HA: 0.01 mg/L (lifetime) [9]
• TLV: Not Available

Basic Manufacturer:

Ciba-Geigy Corporation
P.O. Box 18300
Greensboro, NC 27419-8300

• Phone: 800-334-9481
• Emergency: 800-888-8372
  

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.