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The information in this profile may be out-of-date.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

Metiram

Trade and Other Names: Trade or other names for metiram include arbatene, NIA 9102, Polyram, Polyram-Combi, and Zinc metiram.

Regulatory Status: Metiram is a practically nontoxic compound in EPA toxicity class IV. Labels for products containing it must bear the Signal Word CAUTION. It is a General Use Pesticide (GUP).

Chemical Class: ethylene(bis)dithiocarbamate

Introduction: Metiram may be used to prevent crop damage in the field, during storage, or transport. Metiram is effective against a broad spectrum of fungi and is used to protect fruits, vegetables, field crops, and ornamentals from foliar diseases and damping off.

Formulation: Not Available

Toxicological Effects:

• Acute toxicity: Metiram is practically nontoxic when ingested, with reported oral LD50 values of greater than 6180 mg/kg to greater than 10,000 mg/kg in rats, greater than 5400 mg/kg in mice, and 2400 to 4800 mg/kg in guinea pigs [1,4]. The dermal LD50 is greater than 2000 mg/kg in rats, indicating slight toxicity [3]. It is reported to be a mild skin and eye irritant [4]. Via the inhalation route, it is slightly toxic with a reported 4-hour inhalation LC50 of greater than 5.7 mg/L [3]. Metiram is a cholinesterase inhibitor. Early symptoms of cholinesterase inhibition are blurred vision, fatigue, headache, vertigo, nausea, pupil contraction, abdominal cramps, and diarrhea. Severe inhibition of cholinesterase may cause excessive sweating, tearing, slowed heartbeat, giddiness, slurred speech, confusion, excessive fluid in the lungs, convulsions, and coma.
• Chronic toxicity: When rats were fed metiram at dietary doses of 50 mg/kg/day 5 days a week for 2 weeks, no symptoms of illness were produced. Adverse effects did occur at 500 mg/kg/day [1]. No ill-effect was observed in dogs that received 45 mg/kg daily of the fungicide for 90 days, or 7.5 mg/kg daily for almost 2 years [1]. When metiram was fed to rats at dietary doses of 0.25, 1, 4, or 16 mg/kg/day, the only effect observed was muscle atrophy in rats receiving 16 mg/kg/day [11]. The major toxicological concern in situations of chronic exposure to metiram, however, is ethylenethiourea (ETU), a contaminant and a breakdown product of metiram that has been shown to cause birth defects and cancer in experimental animals.
• Reproductive effects: Pregnant rats fed 80 and 160 mg/kg/day exhibited reduced rates of body weight gain. Litter size was reduced for rats fed 0.25, 2 or 16 mg/kg/day metiram. Rats receiving the 16 mg/kg/day dose also exhibited decreases in parental body weight and in food consumption [1]. The evidence suggests that reproductive effects are unlikely in humans under normal circumstances.
• Teratogenic effects: No teratogenic effects were found in female rats fed 40, 80 and 160 mg/kg/day of metiram [1,11].
• Mutagenic effects: The majority of mutagenicity studies on metiram have been negative. Out of six tests performed, only one highly sensitive test indicated that metiram may be mutagenic [10,11]. These data indicate that metiram is either nonmutagenic or weakly mutagenic.
• Carcinogenic effects: All of the EBDC pesticides can be degraded or metabolized into ethylenethiourea (ETU), which has been shown to produce cancer in mice and rats [31]. However, other EBDCs do not appear to be carcinogenic. There were no data available regarding the carcinogenic properties of metiram itself.
• Organ toxicity: No data were available regarding the target organs of metiram. It is likely that its target organs will be similar to those affected by closely related compounds such as maneb and mancozeb. Those compounds exert their principal effects on the thyroid [1].

• Fate in humans and animals: Metiram is not well absorbed through the skin; less than 1% of a 240 mg/kg dose, applied topically, was absorbed through the skin of rats after 8 hours [31]. Metabolic fate studies in rats indicate that ingested metiram is readily absorbed by the body and eliminated through the urine and feces. Residues remaining in the body were highest in the kidneys, thyroid, and gastrointestinal tract and were higher in females than in males [31]. In mammalian tissues the ethylene(bis)dithiocarbamates break down into ETU [2].

Ecological Effects:

• Effects on birds: Metiram is slightly toxic to birds, with 5- to 8-day LC50 values in both mallard ducks and bobwhite quail of greater than 3712 ppm [3,4].
• Effects on aquatic organisms: Metiram is slightly to moderately toxic to fish; reported 96-hour LC50 values are 85 mg/L in carp and 1.1 mg/L in rainbow trout [1,11]. The 48-hour LC50 for metiram in harlequin fish is 17 mg/L [1,11].
• Effects on other organisms: Metiram is practically nontoxic to bees; the reported oral LD50 is greater than 40 ug per bee, and the contact LD50 is reported to be greater than 16 ug per bee [3].

Environmental Fate:

• Breakdown in soil and groundwater: Metiram is probably similar in its environmental fate to closely related compounds such as maneb and mancozeb. They are of low persistence and are strongly bound to most soils [20]. This property, and their low water solubilities, indicate that they probably do not pose a significant risk to groundwater. They are unstable in the presence of atmospheric moisture and oxygen and are rapidly degraded in biological systems to ETU and other metabolites [31]. These products are of moderate persistence and more mobile, and therefore may pose a slight risk to groundwater. ETU, the primary metabolite of metiram in water, has been detected (at 0.016 mg/L) in only 1 out of 1295 drinking water wells tested [2].
• Breakdown in water: Breakdown of metiram to ETU is very rapid, mainly by hydrolysis, and to a lesser degree by photodegradation [31].
• Breakdown in vegetation: Metiram is not taken up by plants to a significant degree [3].

Physical Properties:

• Appearance: Metiram is a yellow powder at room temperature [3].
• Chemical Name: zinc ammoniate ethlenebis(dithiocarbamate)-poly(ethylene thiuram disulfide) [3]
• CAS Number: 9006-42-2
• Molecular Weight: 1088.70
• Water Solubility: <1 mg/L [3]
• Solubility in Other Solvents: practically insoluble in most organic solvents [3]
• Melting Point: Decomposes at 140 C [3]
• Vapor Pressure: 0.01 mPa @ 20 C [3]
• Partition Coefficient: 0.3010 [3]
• Adsorption Coefficient: 500,000 (estimated) [20]

Exposure Guidelines:

• ADI: 0.03 [33]
• MCL: Not AVailable
• RfD: Not Available
• PEL: Not Available
• HA: Not Available
• TLV: Not Available

Basic Manufacturer:

BASF Corp.
Agricultural Products Group
P.O. Box 13528
Research Triangle Park, NC 27709-3528

• Phone: 800-669-2273
• Emergency: 800-832-4357
  

References:

References for the information in this PIP can be found in Reference List Number 4

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.