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':XTOXNET PIP-DIURON http://acc.orst.edu/cgi-bin/mfs/01/pips/diuron.htm of the pesticide over time included changes in blood chemistry, increased mortality, growth retardation, abnormal blood pigment, and anemia. When fed small amounts of diuron in food for 2 years, animal species showed no adverse effects [4,8]. • Reproductive effects: Daily low doses of diuron fed to female rats through three successive generations caused significantly decreased body weight of offspring in the second and third litters. The fertility rate remained unaffected [8]. It is unlikely that diuron will cause reproductive effects in humans at expected levels of exposure. • Teratogenic effects: Diuron is teratogenic at high doses. Administered to pregnant rats on days 6 through 15 of gestation, it produced no birth defects in the offspring at doses of up to 125 mg/kg/day. However, doses of 250 mg/kg/day caused wavy ribs, extra ribs, and delayed bone formation. There were also weight decreases in offspring at 500 mg/kg/day. There was no increase in the severity of the rib deformation at this higher dose [4,8]. Pregnant mice given very high doses of diuron (nearly 2000 mg/kg/day) exhibited reproductive and embryotoxic effects. Developmental effects were found in their offspring [4,8]. • Mutagenic effects: Diuron does not appear to be mutagenic. The majority of tests have shown that diuron does not produce mutations in animal cells or in bacterial cells [4,8]. • Carcinogenic effects: Limited evidence indicates that low level exposures to diuron does not cause cancer [10]. • Organ toxicity: Low doses of diuron over extended periods of time can cause enlargement to the liver and the spleen [10]. • Fate in humans and animals: Diuron is excreted in the feces and urine of test animals. Breakdown of the compound is similar in animals, plants, and soil. Cows fed very low doses of diuron in their diets had small amounts of residues in whole milk. Cattle fed small amounts accumulated low levels of diuron in fat and muscle, liver, and kidney [4,8]. Ecological Effects: • Effects on birds: Diuron is slightly toxic to birds. In bobwhite quail, the dietary LC50 is 1730 ppm. In Japanese quail and ring-necked pheasant, it is greater than 5000 ppm. The LC50 is approximately 5000 ppm in mallard ducks [4,8]. • Effects on aquatic organisms: The LC50 (48 hour) values for diuron range from 4.3 mg/L to 42 mg/L in fish, and range from 1 mg/L to 2.5 mg/L for aquatic invertebrates. The LC50 (96-hour) is 3.5 mg/L for rainbow trout [4,8]. Thus, diuron is moderately toxic to fish and highly toxic to aquatic invertebrates. • Effects on other organisms: Diuron is non-toxic to bees [4]. Environmental Fate: • Breakdown in soil and groundwater: Diuron is moderately to highly persistent in soils. Residue half-ives are from 1 month to 1 year [19]. Some pineapple fields contained residues 3 years after the last application. Mobility in the soil is related to organic matter and to the type of the residue. The metabolites are less mobile than the parent compound [20]. In California, diuron has been found in groundwater in the 2 to 3 ppb range. It has also been found in Ontario groundwater where it has been linked with land applications [20]. • Breakdown in water: Diuron is relatively stable in neutral water. Microbes are the primary agents in the degradation of diuron in aquatic environments [20]. • Breakdown in vegetation: Diuron is readily absorbed through the root system of plants and less readily through the leaves and stems [4]. 2 of'3 5/12/00 2:22 PM