Fluridone

LD50 /Colinus virginianus/ (Bobwhite quail) oral >2000 mg/kg

LC50 /Colinus virginianus/ (Bobwhite quail) dietary >5000 mg/kg/8 days

LC50 /Anas platyrhynchos/ (Mallard duck) dietary >5000 mg/kg/8 days

LC50 /Oncorhynchus mykiss/ (Rainbow Trout) 11.7 mg/L/ 96 hr /Conditions of bioassay not specified in source examined/

For more Ecotoxicity Values (Complete) data for FLURIDONE (34 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values ranged from 350 to 2,462(2-4), indicate that fluridone is expected to have low to slight mobility in soil(SRC). The pKa of fluridone is 12.3 (tertiary amine)(6), indicating that this compound will primarily exist in the protonated form in the environment and cations generally adsorb more strongly to organic carbon and clay than their neutral counterparts(7). Volatilization of fluridone from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 3.5X10-9 atm-cu m/mole(SRC), derived from its vapor pressure, 9.8X10-8 mm Hg(5), and water solubility 12 mg/L(6). Fluridone is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(5). A biodegradation half-life of 360 days was reported in aerobic soil(8). In field studies using different soil types, <10% of the originally applied fluridone was found after 220 days in Miller clay and 20% was found remaining after 385 days in Lufkin fine sandy loam soil(9). In laboratory studies, fluridone persistence in non-sterilized soils after 210 days was 62, 44, 10, and 5% in Lufkin fine sandy loam, Miller clay, Hidalgo sandy clay loam, and Brennan fine sandy loam, respectively(9). In Miller clay and Lufkin fine sandy loam no difference was observed in the rate of fluridone degradation between sterilized and non-sterilized samples; however, significant differences in degradation were observed between sterilized and non-sterilized Brennan fine sandy loam and Hidalgo sandy clay loam(9).

AQUATIC FATE: Based on a classification scheme(1), Koc values ranged from 350 to 2,462(2-4), indicates that fluridone may adsorb to suspended solids and sediment(SRC). The pKa of fluridone is 12.3 (tertiary amine)(7), indicating that this compound will primarily exist in the protonated form in the environment and cations generally adsorb more strongly to suspended solids and sediment than their neutral counterparts(8). Volatilization from water surfaces is not expected(5) based upon an estimated Henry's Law constant of 3.5X10-9 atm-cu m/mole(SRC), derived from its vapor pressure, 9.8X10-8 mm Hg(6) and water solubility, 12 mg/L(7). According to a classification scheme(9), BCF values ranging from 0 to 91(10-13), suggests the potential for bioconcentration in aquatic organisms is low to moderate(SRC). Fluridone is stable to hydrolysis(4,14). Aqueous photolysis half-lives ranging from 1 to 6 days were reported in various studies(4). Photodegradation was found to be the major degradation pathway of fluridone in aquatic systems under actual-use conditions(15). A half-life of 12 months was reported for fluridone in sediment under laboratory conditions and 17 weeks under field conditions(15). Fluridone was reported to dissipate with average half-lives of 20 days and 3 months in pond water and in pond hydrosoil, respectively(16). A half-life of 4 days was observed for fluridone after treatment in a pond(17). A half-life of 1 year or more was observed for fluridone in hydrosoils(17).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), fluridone, which has a vapor pressure of 9.8X10-9 mm Hg at 25 °C(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase fluridone may be removed from the air by wet or dry deposition(SRC).

/AQUATIC SPECIES/ The acute median lethal concentrations (LC50s) of fluridone were 4.3 plus or minus 3.7 mg/L for invertebrates and 10.4 plus or minus 3.9 mg/L for fish. In chronic studies, no effects were detected when daphnids (Daphnia magna ) were continuously exposed to fluridone concentrations of 0.2 mg/L or less for 32 days, amphiopods (Gammarus pseudolimnaeus ) to 0.6 mg/L or less for 60 days or midge larvae (Chironomus plumosus ) to 0.6 mg/L or less for 30 days. Fathead minnows (Pimephales promelas ) were not affected by continuous exposure to fluridone concentration of 0.48 mg/L or less over their life cycle. The growth and survival of channel catfish (Ictalurus punctatus ) were not adversely affected by continuous exposure to fluridone concentrations of 0.5 mg/L or less for 60 days after hatching.

Fluridone was detected in orchardgrass and alfalfa at concentrations of 0.11 and 0.07 ppm, respectively, following irrigation of 26 associated crops with water containing fluridone(1). The detection limit for fluridone in this study was 0.05 ppm(1).

Fluridone

Ocular

8 x 10 ^-2 mg/kg-day

Koc values for fluridone measured in 6 soils were reported to range from 350 to 2,462(1-3). According to a classification scheme(4), these Koc values suggest that fluridone is expected to have low to slight mobility in soil. The pKa of fluridone is 12.3(5), indicating that this compound will primarily exist in the protonated form in the environment and cations generally adsorb more strongly to organic carbon and clay than their neutral counterparts(6).

AEROBIC: A half-life of 12 months was reported for fluridone in sediment under laboratory conditions and 17 weeks under field conditions(1). Fluridone was reported to dissipate with average half-lives of 20 days and 3 months in pond water and in pond hydrosoil, respectively(2). A half-life of 4 days was observed for fluridone after treatment in a pond(3). A half-life of 1 year or more was observed for fluridone in hydrosoils(3). Photodegradation was found to be the major degradation pathway of fluridone in aquatic systems under actual-use conditions(1). In field studies using different soil types, <10% of the originally applied fluridone was found after 220 days in Miller clay and 20% was found remaining after 385 days in Lufkin fine sandy loam soil(4). In laboratory studies, fluridone persistence in non-sterilized soils after 210 days was 62, 44, 10, and 5% in Lufkin fine sandy loam, Miller clay, Hidalgo sandy clay loam, and Brennan fine sandy loam, respectively(4). In Miller clay and Lufkin fine sandy loam no difference was observed in the rate of fluridone degradation between sterilized and non-sterilized samples; however, noticeable differences in degradation were observed between sterilized and non-sterilized Brennan fine sandy loam and Hidalgo sandy clay loam(4). A half-life of 360 days was reported in aerobic soil(5).

New Active Ingredients ... includes pesticide active ingredients initially registered after November 1, 1984, that currently have active product registrations. By law, these newer pesticides are not subject to the reregistration program. They must, however, meet the new safety standard of the FQPA, and will be reviewed on a 15-year cycle under the registration review program. ... Active Ingredient Number: 112900; Type of Pesticide: conventional - herbicide; Use Site: aquatic/non-food; Year: 1986.

Used as an systemic herbicide for control of aquatic weeds in ponds and lakes; No direct food uses; [Reference #1]

Farming (Pesticides) [Category: Industry]

For fluridone (USEPA/OPP Pesticide Code: 112900) ACTIVE products with label matches. /SRP: Registered for use in the U.S. but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./

Used as an aquatic herbicide for control of most submerged and emerged aquatic plants (including Utricularia spp., Ceratophyllum demersum, Elodea canadensis, Myriophyllum spp., Najas guadalupensis, Potamogeton spp., Hydrilla verticillata and Panicum purpurascens) in ponds, lakes, reservoirs, irrigation ditches, etc. Application rates depend on target weeds and also the desired selectivity; for ponds a concentration of 45-90 ppb; for lakes and reservoirs 10-90 ppb. Maximum total application to a single body of water 150 ppb per annual growth cycle.

Formulations: Aqueous suspension, pellets.

Trade Name: Avast, Sonar

4(1H)-Pyridinone, 1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-: ACTIVE

Cotton is the only crop which has been found to be tolerant.

It is particularly useful for the control of eurasian milfoil in the northern tier states and for hydrilla in the southern states. It inhibits carotene synthesis which causes the loss of chlorophyll. It is typically applied to the whole water body because it requires a contact time of 45 days to be effective. The labels permit single treatments of up to 90 ppb for whole lake treatments and 150 ppb for partial lake treatments, with a maximum cumulative application of 150 ppb per growth cycle. If the treatment area is within 1/4 mile of a water intake, the fluridone concentration must be maintained below 20 ppb.