Product: SURFLAN AS
Active ingredient: ORYZALIN 40.4%
Other ingredients: 59.6% Propylene Glycol (undisclosed amount); other ingredients withheld as trade secrets by the manufacturer. Type: Dinitroaniline HERBICIDE(systemic)
Mode of Action: Inhibits seed germination; interferes with cellular respiration and may inhibit microtubule polymerization/function, which is important to numerous vital cellular activities.
TOXICOLOGY
Oryzalin, is considered a possible human carcinogen by U.S. EPA, which has ranked it group C, meaning that there is evidence it causes cancer in animals. Tumor formation was observed in rats at the lowest dose tested, including both benign and malignant thyroid, skin, breast, and other tumors (Caltrans 1991). Oryzalin is also suspect as a carcinogen because it is structurally related to 2,4 diaminoanisole sulfate, a chemical which causes similar malignant tumor formation in test animals. Other related compounds have shown carcinogenic properties (EPA 1989).
The liver, blood and blood forming tissues are the targets of damage caused by oryzalin; it is toxic to bone marrow (Lappe 1988). Animal tests have revealed adverse changes in blood chemistry, cholesterol levels, anemia, liver, spleen and bone marrow (Caltrans 1991).
Oryzalin contains a contaminant (inadvertant byproduct of manufature) ingredient, N nitrosodipropylamine (NDPA), a confirmed human carcinogen listed by the Office of Environmental Health Hazard Assessment under California's Proposition 65 (EPA 1986b). EPA is concerned about the toxicity of ammonium 3,5 dinitro 4 di(n propyl)amino benzene sulfonate, another contaminant of oryzalin (Caltrans EIR 1991).
Lab animals exposed to oryzalin showed chromosome mutations (EPA1989).
Prolonged exposure may cause irritation or allergic reactions in some individuals. Higher temperatures may generate a vapor level sufficient to cause irritation and other effects when inhaled. (Elanco Products, no date[recent])
ENVIRONMENTAL FATE AND EFFECTS
Oryzalin is a high priority candidate for evaluation as a toxic air contaminant, having scored high in all categories used to assess priority (DPR 1994).
The manufacturer's Material Safety Data Sheet states that there is a severe explosive potential of oryzalin as an airborne dust.
One-half of oryzalin remains intact in soil for 30 to 160 days.
Orzalin adsorbs strongly to soil particles and is not very soluble in water, thus it is not readily leachable and is not considered a potential threat to groundwater. Oryzalin can enter aquatic systems as a complex with silt and soil particles, however (Caltrans 1991), and in that form can become available to aquatic organisms.
Oryzalin is moderately to highly toxic to fish and aquatic invertebrates. It has a strong tendency to bioconcentrate in aquatic organisms and was ranked eighth among pesticides in California due to this factor (Pease 1996).
In terms of acute toxicity [immediate death], oryzalin is relatively nontoxic to moderately toxic to mammals based on laboratory studies using animals. It is slightly to moderately toxic to birds. Long term effects of exposure for most mammals, bees and birds are not known. There is no information available addressing toxicity of oryzalin to reptiles, amphibians, soil invertebrates, fungi or aquatic plants (Caltrans1991). |
