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Daminozide

Publication Date: 9/93

TRADE OR OTHER NAMES

Alar, B-Nine, Dazide, Kylar. Other names include aminozide, SADH and B-995.

REGULATORY STATUS

All use of daminozide on food crops was voluntarily canceled by the manufacturer in November, 1989. It is currently registered only for use on ornamental and bedding plants (5).

Products containing daminozide must bear the signal word "Caution" (1).

INTRODUCTION

Daminozide is a plant growth regulator formerly used on certain fruit crops to improve the balance between vegetative growth and fruit production, to improve fruit quality, and to synchronize fruit maturity (3). It is available in water soluble powder formulations (1).

Unsymmetrical dimethyl hydrazine (UDMH) is a contaminant of commercial daminozide and a metabolite of daminozide which is formed in the body, during food processing, or when spray mixes containing daminozide are left standing in the mixing tank. Commercial daminozide contains 0.005% (50 ppm) UDMH. A metabolism study in swine has indicated that 1% of ingested daminozide is converted to UDMH. EPA estimates that 0.012% of a daminozide solution converts to UDMH when allowed to stand in a tank for 24 hours (5).

TOXICOLOGICAL EFFECTS

ACUTE TOXICITY

Daminozide is relatively non-toxic to mammals (1). It may cause skin or eye irritation (2). Contact with the skin or eyes and inhalation of spray mists should be avoided.

Changes in liver function have been observed in animals given very high single doses (2).

The oral LD50 for daminozide in rats is 8,400 mg/kg, and in mice is 6,300 mg/kg. Its dermal LD50 on rabbits is > 1600 mg/kg. The inhalation LC50 in rabbits is > 147 mg/l (1).

CHRONIC TOXICITY

The NOEL for a 2-year study with rats fed 5, 25, 250 or 500 mg/kg/day was 5 mg/kg. Effects observed at higher doses included atrophy of ovaries and enlargement of the liver bile duct (hyperplasia) (9). No effects were seen in dogs fed 7.5, 75 or 187.5 mg/kg/day daminozide for one year (9).

The principal health concern related to use of daminozide is the carcinogenic potential of UDMH, a contaminant and metabolite of daminozide.

Reproductive Effects

A 3-generation study with rats fed 300 mg/kg showed no significant effects on fertility or reproductive capacity (3). The reproductive NOEL for a 2-generation study with rats fed 5, 50 or 500 mg/kg/day was 5 mg/kg/day (9).

Teratogenic Effects

No birth defects occurred in the offspring of pregnant rats fed 500 mg/kg/day, the highest dose tested (3). When pregnant rats were given 85, 390 or 1,800 mg/kg/day, ossification of the bones of the sternum and spine occurred in offspring at 1,800 mg/kg/day. The reproductive NOEL for this study was 390 mg/kg/day (9). No teratogenic or developmental effects occurred in the offspring of pregnant rabbits given 50, 150 or 300 mg/kg/day (9).

Mutagenic Effects

Several studies have shown that daminozide is not mutagenic in either in vivo or in vitro tests (3, 5). There is inconclusive evidence that UDMH may be mutagenic. Dimethylnitrosamine (DMN), another metabolite of daminozide, is mutagenic (5).

Carcinogenic Effects

Unsymmetrical dimethyl hydrazine (UDMH) is a contaminant of commercial daminozide and a metabolite of daminozide which is formed in the body, during food processing, or when spray mixes containing daminozide are left standing in the mixing tank (5). Both daminozide and UDMH have caused increases in the incidence of benign and malignant tumors in test animals (6). Malignant tumors were found in female rats given dietary doses of 5000 and 10,000 ppm (2). Malignant and benign blood vessel tumors also occurred in treated mice (2).

EPA has classified daminozide and its metabolite UDMH as probable human carcinogens based on the occurrence of tumors in laboratory animals (5).

No increase in tumor formation occurred in rats fed 5, 25, 250 or 500 mg/kg/day of daminozide for two years, nor in mice fed 15, 150, 300 or 500 mg/kg/day for 2 years (9).

When rats were given UDMH in their drinking water at concentrations of 0, 1, 50 or 100 ppm for 2 years, there was a significant, but slight, dose- related increase in liver tumors in females, and bile duct hyperplasia and inflammation of the liver in males receiving 100 ppm and in females receiving 50 and 100 ppm (5).

Mice given UDMH in their drinking water for 2 years at 0, 1, 5 or 10 ppm for males and 0, 1, 5 or 20 ppm for females exhibited decreased survival at the highest dose tested. This study also showed a significant increase in the incidence of lung tumors (5, 6).

In another study, mice given UDMH in their drinking water for two years at 0, 40 or 80 ppm exhibited a significant increase in the incidence of lung and vascular tumors (5).

Fate in Humans and Animals

96-hours after administration of a single oral dose of 5 mg/kg to miniature swine, daminozide was detected in all body tissues at levels up to 73 ppb. The highest levels were found in the liver and kidney. Urinalysis showed that about 84% of the dose was eliminated in the urine and that 1% of the dose was metabolized to UDMH (5).

The majority of daminozide residues ingested by milk animals is rapidly excreted in the urine and feces (7).

ECOLOGICAL EFFECTS

Effects on Birds

Daminozide is not toxic to birds. Its 96-hour LC50 in quail is 5,620 mg/kg (1). The 8-day dietary LC50 for mallard ducks and bobwhite quail is 10,000 mg/kg (3).

Effects on Aquatic Organisms

Daminozide is of low toxicity to fish. Its 96-hour LC50 in rainbow trout is 149 to 306 mg/l, and in bluegill is 423 to 552 mg/l (1, 3). The 48-hour LC50 for Daphnia sp., a small freshwater crustacean, is 98.5 mg/l (3).

Daminozide does not bioconcentrate in fish (7).

Effects on Other Animals (Nontarget species)

Daminozide is of low toxicity to terrestrial wildlife (7). It is non- toxic to bees (4).

ENVIRONMENTAL FATE

Breakdown of Chemical in Soil and Groundwater

Daminozide is soluble in water (1) and very mobile in soils (8). It appears to leach, but because it does not persist in soil, it is unlikely to contaminate groundwater (7).

Daminozide appears to resist photodegradation, but it is subject to degradation by soil microorganisms (7). The half-life of daminozide in soil is approximately 21 days (4). In field tests, 50% of applied Alar disappeared within one week. In greenhouse tests, 90% of the applied Alar disappeared within 2 weeks (8).

Breakdown of Chemical in Surface Water

In water, daminozide degrades to UDMH (7).

Breakdown of Chemical in Vegetation

Daminozide is rapidly absorbed through the leaves, roots and stems of plants. It is translocated within plants and can accumulate in roots, fruits and other plant parts. It does not accumulate in subsequent crops grown on treated sites (7).

PHYSICAL PROPERTIES AND GUIDELINES

Daminozide is a colorless to white, stable crystalline solid (1, 2). It is stable under normal temperatures and pressures, but poses a slight fire hazard when exposed to heat or flame, and a fire and explosion hazard in the presence of strong oxidizers. Daminozide may burn, but it does not readily ignite. Contact with strong oxidizers, excessive heat, sparks and open flame should be avoided. Thermal decomposition products may include toxic oxides of carbon and nitrogen (2).

Extended storage of daminozide solutions will result in excessive hydrolysis to UDMH. Product labels require use of daminozide spray solutions within 24 hours of mixing (7).

Exposure Guidelines:

No occupational exposure limits have been established for daminozide by OSHA, NIOSH or ACGIH (2).

Physical Properties:

CAS #: 1596-84-5
Chemical name: butanedioic acid mono (2,2-dimethyl hydrazide). Also called succinic acid 2,2-dimethyl hydrazide or N-dimethylaminosuccinic acid.
Chemical Class/Use: hydrazide plant growth regulator
Density: 1.34 gm/cc (8)
H20 solubility: 10% (2)
Solubility in other solvents: Soluble in methanol, acetone, and polar organic solvents. Practically insoluble in aromatic and aliphatic hydrocarbon solvents (2).
pH: 3.8 at 0.5% aqueous solution (2)
Melting point: 309-311 degrees F (154-155 degrees C) (2)
Vapor pressure: < 0.9975 mm Hg at 20 degrees C (2)

BASIC MANUFACTURER

Uniroyal Chemical Co., Inc.
World Headquarters
Middlebury, CT 06749

Review by Basic Manufacturer:

Comments solicited: April, 1993
Comments received: April, 1993

REFERENCES

  1. Meister, R.T. (ed.). 1992. Farm Chemicals Handbook '92. Meister Publishing Company, Willoughby, OH.
  2. Occupational Health Services, Inc. 1992 (Dec. 30). MSDS for Daminozide. OHS Inc., Secaucus, NJ.
  3. British Crop Protection Council. 1983. The Pesticide Manual: A World Compendium, 7th ed. Croydon, England.
  4. Royal Society of Chemistry. 1983. The Agrochemicals Handbook. The University, Nottingham, England.
  5. US Environmental Protection Agency. Oct. 8 1992. Daminozide; Notice of final determination for non-food uses and termination of the daminozide Special Review. Federal Register 57 (196): 46436-44.
  6. US Environmental Protection Agency. Feb. 10, 1989. Pesticide tolerance for daminozide. Federal Register 54 (27): 6392-6.
  7. US Environmental Protection Agency. June 30, 1986. Chemical Fact Sheet for Daminozide (Fact Sheet Number 26). US EPA, Washington, DC.
  8. Uniroyal. Alar Growth Retardant, Technical Data Sheet. Uniroyal Corp., Middlebury, CT.
  9. Uniroyal. April 14, 1993. Database on daminozide. Health and Regulatory Compliance Dept., Uniroyal Corp., Middlebury, CT.