Product: Demethogon; Clean Crop
Active ingredient: DIMETHOATE 25%
Other ingredients: 75% Withheld as trade secret by manufacturer
Type: Organophosphate INSECTICIDE MITICIDE (Systemic)
Mode of Action: Inhibits nerve function by binding to acetylcholinesterase, an enzyme necessary for nerve transmissions.
Of the total dimethoate used in California in 1994, 6% was applied to winegrapes. It was ranked sixth of 25 top hazard pesticides in California agriculture based on numerous categories (Pease 1996). It exhibits a broad range of toxicity in the environment. Most dimethoate products were canceled by the EPA in 1981.
TOXICOLOGY
According to the U.S.EPA, dimethoate is a possible human carcinogen.
Dimethoates vapors are harmful (Product label). It has a high oral and dermal acute toxicity. It is an eye irritant. Dimethoate is eighth for pesticide related non agricultural illness in California (Pease 1996).
Dimethoate is readily absorbed through the skin and lungs. It is classified by the U.S. EPA as a category II nerve toxin that inhibits the enzyme acetochlolinesterase, which is vital to normal transmission of nerve impulses. Symptoms range from temporary behavioral disturbances, hair loss and nausea to persistent weakness, paralysis and reduced intelligence (WHO 1986).
Due to an abnormal decrease in reproductive capacity demonstrated in laboratory animal studies, California Department of Pesticide regulation notes that dimethoate has a possible adverse effect on reproduction (DPR 1996). In one study, test animals exhibited an increase in abnormal and dead sperm and decline in body weight, libido, and sperm volume and concentration, suggesting a testosterone decrease may result from exposure to dimemethoate (Salem 1988).
Lab animals exposed to dimethoate showed abnormal DNA synthesis (DNA damage) in liver cells (DPR 1996).
ENVIRONMENTAL FATE AND EFFECTS
Dimethoate is a high priority candidate for evaluation as a toxic air contaminant (DPR 1994). Soil evaporation is high, from 23-40% (Pease 1996).
Dimethoate is highly hazardous to terrestrial ecosystems (Ibid).
One-half of dimethoate can be found in soil from 4 up to 122 days after application. It does not adsorb to soil and can exhibit very high ability to travel (seep, leach) through soil depending on soil type and moisture (Howard 1991). In California, dimethoate has been detected in wells, and there was an unconfirmed report that it was detected in groundwater (Pease 1995).
Dimethoate is high in acute toxicity to birds and aquatic invertebrates (Pease 1996). It is highly toxic to bees (CIAS 1981). It is low to highly toxic in fish and highly toxic to crustaceans (WHO 1989).
Wastes of this product are extremely hazardous. If dimethoate foumulations "cannot be disposed of by use," hazardous waste officials must be contacted for disposal (Product label). |
