Product: DITHANE
Active ingredient: MANCOZEB 37%-80%
Other ingredients: Withheld as trade secrets by the manufacturer.
Type: Ethylene bisdithiocarbamate (EBDC) FUNGICIDE
Mode of action: Inhibits acetaldehyde dehydrogenase, an enzyme vital to normal metabolism, resulting in buildup of harmful compounds in the organism's cells.
Of the total mancozeb used in California in 1994, 8% was applied to wine grapes.
TOXICOLOGY
Mancozeb is categorized by U.S. EPA as a probable human carcinogen, meaning that there is sufficient documentation of the carcinogenic potential of mancozeb in animal studies. EPA proposed to cancel most uses of mancozeb and other EDBC pesticides in 1989 due to unacceptably high cancer risks. EPA reversed its decision in 1992 even though a National Toxicology Program study yielded clear evidence of the carcinogenicity of mancozeb's breakdown product, ETU (EDBC/ETU Task Force 1991). Mancozeb is listed as a cancer-causing chemical by California's Office of Environmental Health Hazard Assessment under Proposition 65.
In its Pesticide Fact Sheet for mancozeb EPA states: "The major toxicological concern from exposure to mancozeb is the hazard to the human thyroid from the presence of ethylenethiourea (ETU), a contaminant, degradation product, and metabolite present in mancozeb and other EDBC products. ETU is an acknowledged goitrogen, teratogen and oncogen" (thyroid toxin, causes birth defects and tumors). Mancozeb breaks down to ETU in plants, animals, soil and water.
Effects observed in long-term, low-dose exposure studies of test animals included decreases in weight gain and food consumption, increased kidney, heart, liver, spleen, and testicle mass, altered thyroid hormone levels and thyroid cancers. Chronic toxicity studies demonstrasted thyroid abnormalities and altered levels of thyroid hormones (EDBC/ETU T.F. 1991).
Experimental evidence suggests mancozeb may cause mutations in chromosomes (DPR 1995).
In a reproductive toxicity test, pituitary abnormalities and thyroid and kidney problems were observed. Due to this and other evidence, mancozeb is considered to disrupt the endocrine system (Colborn 1993).
Mancozeb may be a skin sensitizer, causing allergic and contact dermatitis in humans (USFS 1996).
ENVIRONMENTAL CHARACTERISTICS
Mancozeb is listed as a toxic air contaminant in California (DPR 1994).
In laboratory tests, one-half of mancozeb was found in soil 60 days after application (USFS 1996).
As an acute (immediate death) toxin, mancozeb is highly toxic to warm water fish and moderately toxic to coldwater fish (Ibid).
Mancozeb inhibits germination in some plants (R. Carson Council 1992).
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