Product: PRINCEP
Active ingredient: SIMAZINE 40-90%
Other ingredients: 10-60% Identity withheld as trade secret by the manufacturer
Type: Translocated triazine HERBICIDE
Mode of Action: Inhibits photosynthesis by interfering with electron transport across the chloroplast membrane.
A U.C. Berkeley School of Public Health report ranked simazine as the tenth highest hazardous pesticide in California agriculture (Pease 1996). Of simazine used in California during 1994, 12% was applied to wine grapes.
TOXICOLOGY
Simazine is listed by U.S. EPA as cancer class C, or possible human carcinogen, meaning that there is animal evidence of simazine's carcinogenicity. Simazine was ranked as eighth for cancer causation of pesticides in use in California (Pease 1996). Kidney, breast and ovarian cancers were observed in laboratory animals tested with simazine (DPR 1993).
Other triazine herbicides (including atrazine and cyanazine) have been linked to breast cancer. Recent scientific research provides evidence that atrazine, a close relative to simazine, promotes breast and other cancers through changing the metabolism of estrogen in the body, resulting in elevated levels of the harmful metabolite of estradiol, 16 alpha hydroxyestrone (Davis and Bradlow 1995). This raises the issue that simazine and other triazine herbicides may be endocrine disrupting chemicals.
In low dose toxicity tests, test animals demonstrated stomach ulcers and intestinal bleeding. In other studies, test animals exhibited blood abnormalities, including reductions in red and white cell counts and elevated cholesterol, organic phosphate levels, and kidney stones. Increased brain, liver, kidney, and testicle mass to body mass ratios, and decreased heart mass, have also been demonstrated (Caltrans 1991).
ENVIRONMENTAL FATE AND EFFECTS
Simazine is a major contaminant of groundwater in the U.S., and is the second most frequently detected pesticide contaminant of groundwater in California (Pease 1995). Simazine was the most frequently detected pesticide in wells tested in California during 1995 (DPR 1996). Simazine has also been detected in surface water. Persistence in aquatic systems is moderate to long, with one-half persisting from 50 to 700 days in ponds (EPA 1987).
Persistence in aquatic systems is moderate to long, with one-half still intact from 50 to 700 days after entering ponds (EPA 1987). The major route by which simazine leaves water is biological transformation in vascular plants, algae and bacteria. (Caltrans 1991).
Simazine is a high priority candidate for evaluation as a toxic air contaminant. (DPR 1994).
One-half is found in soil from 56 to more than 84 days later, with detectable residues present in some cases for as long as three years (EPA 1987).
Fish vary in their sensitivity to simazine, with the majority of species moderately sensitive. Soil invertebrates and some species of earthworms are considered to be sensitive to the toxicity of simazine. No acute toxicity information or long term effects data are available for reptiles or amphibians (Caltrans 1991). |
