Florasulam

359.28

359.28

604-488-1

00A64ZX8NB

DTXSID7044340

Solid

107

-1.22 (pH 7.0)

1.53

220-221° (dec) (Van Heertum); also reported as 193.5-230.5° (Thompson)

1.676

In water, 0.121 (purified, pH 5.6-5.8); 0.084 (pH 5.0); 6.36 (pH 7.0); 94.2 (pH 9) (all in g/L, 20 deg C)

0-6°C

1X10-2 mPa /7.501X10-8 mm Hg/ at 25 deg C

Henry's Law constant = 5.75X10-12 at 25 °C (est)

pKa = 4.54

Hydroxyl radical reaction rate constant = 6.27X10-12 cu cm/molec-sec at 25 °C (est)

UN 3077 9 / PGIII

50/53

60-61

N

Hydrolytically stable for 30 days (pH 5 and 7); DT50 100 days (pH 9) (all 25 deg C)

P273-P501

H410

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

USEPA Office of Prevention, Pesticides and Toxic Substances, Pesticide Fact Sheet for Florasulam (September 2007).[Available from, as of June 1, 2011: http://www.epa.gov/opprd001/factsheets/]

|Warning|H400: Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]|P273, P391, and P501|H400 (100%): Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]|Aggregated GHS information provided by 304 companies from 3 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.|H410: Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]

For several good reasons, .... herbicides ... should be handled and applied only with full attention to safety measures that minimize personal contact. Many formulations contain adjuvants (stabilizers, penetrants, surfactants) that may have significant irritating and toxic effects. A number of premixed formulations contain two or more active ingredients; the companion pesticides may be more toxic than the principal herbicide. Good hygienic practice should not be disregarded just because a pesticide is reported to have a high LD50 in laboratory rodents. /Herbicides/

LC50 Rat inhalation >/ = 5.0 mg/L/4 hr|LD50 Rabbit dermal >/ = 2000 mg/kg|LD50 Mouse oral >/= 5000 mg/kg|LD50 Rat oral >/= 5000 mg/kg

/BIRDS and MAMMALS/ The acute oral toxicity of florasulam to 8-week-old Japanese quail (Coturnix japonica) was assessed over 14 days. Florasulam was administered to the birds by gavage in corn oil as a single oral dose at nominal concentrations of 0 (control), 175, 292, 486, 810, 1350 and 2250 mg ai/kg-bw. Toxic sublethal effects (lower limb weakness, wing droop, reduced reaction to sound and movement) were observed at 292 mg a.i./kg-bw and above, and were more severe at 2250 mg a.i./kg-bw. Mortality was 40, 60, and 100% in the 810, 1350, and 2250 mg ai/kg treatments, respectively. The NOAEL (based on sublethal effects) and LD50 were 175 and 1047 mg ai/kg-bw, respectively. Florasulam is classified as slightly toxic to Japanese quail on an acute oral exposure basis.|/BIRDS and MAMMALS/ The subacute dietary toxicity of florasulam to 11 -day-old Japanese quail and mallard duck (Anas platyrhynchos) was assessed over 8 days. Florasulam was administered to the birds in the diet at nominal levels of 0 (control), 312, 625, 1250, 2500 and 5000 mg ai/kg diet. There were no compound-related toxic effects. The NOAEC and LC50 were 5000 and >5000 mg ai/kg diet, respectively. Florasulam is classified as practically non-toxic to Japanese quail and mallard duck on a subacute dietary exposure basis.|/BIRDS and MAMMALS/ The chronic toxicity of florasulam to 20-week-old bobwhite quail (Colinus virginianus) and 28-week-old mallard duck were assessed over 21 and 23 weeks, respectively. The adult bobwhite quail and mallard duck were fed diets containing florasulam at nominal concentrations of 0 (control), 240, 600 and 1500 mg aikg diet prepared with the aid of acetone and corn oil. There were no compound-related toxic effects at any of the concentrations tested. The NOAEC for chronic toxicity to birds is 1500 mg ai/kg diet.|/AQUATIC SPECIES/ In 96-hour acute static toxicity studies, rainbow trout (Oncorhynchus mykiss) and bluegill sunfish (Lepomis macrochirus) were exposed to florasulam at a concentration of 100 mg ai/L. No mortality or other adverse effects were observed. The 96-hr LC50 and NOAEC values, based on mortality and non-lethal adverse effects, were >I00 and 100 mg ai/L, respectively. Florasulam is classified as practically non-toxic to freshwater fish on an acute exposure basis.|For more Ecotoxicity Excerpts (Complete) data for Florasulam (6 total), please visit the HSDB record page.

Florasulam's production may result in its release to the environment through various waste streams; its use as a herbicide(1) will result in its direct release to the environment(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 160(SRC), determined from a structure estimation method(2), indicates that florasulam is expected to have moderate mobility in soil(SRC). The pKa of florasulam is 4.54(3), indicating that this compound will partially exist in the anion form in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4). Volatilization of florasulam from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 5.7X10-12 atm-cu m/mole(SRC), based upon its vapor pressure, 7.5X10-8 mm Hg(3), and water solubility, 6.36X10+3 mg/L(3). Based on experiments using moist and air dried soil exposed to light and dark the estimated photodegradation half-life on soil in summer at 40 deg N latitude was 14 days(5). Florasulam is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(3). An average biodegradation half-life of 2.4 days with ultimate mineralization to CO2 and non-extractable residues(6) indicates that biodegradation may be an important environmental fate process in soil(SRC).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 160(SRC), determined from a structure estimation method(2), indicates that florasulam is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 5.7X10-12 atm-cu m/mole for the neutral species(SRC), derived from its vapor pressure, 7.5X10-8 mm Hg(4), and water solubility, 6.36X10+3 mg/L(3). A pKa of 4.54(4) indicates florasulam will exist partially in the anion form at pH values of 5 to 9 and therefore volatilization from water surfaces is not expected to be an important fate process(SRC). The measured photodegradation half-life in water at 51.5 deg N was 3.3 days(5). According to a classification scheme(6), an estimated BCF of 3(SRC), from its log Kow of -1.22(4) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). An average biodegradation half-life of 2.4 days with ultimate mineralization to CO2 and non-extractable residues(8) indicates that biodegradation may be an important environmental fate process in water(SRC).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), florasulam, which has a vapor pressure of 7.5X10-8 mm Hg at 25 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase florasulam is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 20 hours(SRC), calculated from its rate constant of 6.3X10-12 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase florasulam may be removed from the air by wet or dry deposition(SRC). Florasulam does not absorb light at wavelengths >300 nm(4), therefore it is not expected to be susceptible to direct photolysis by sunlight(SRC).

The rate constant for the vapor-phase reaction of florasulam with photochemically-produced hydroxyl radicals has been estimated as 6.3X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 20 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Florasulam is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(2). Florasulam does not absorb light at wavelengths >310 nm(3,4) however it may be susceptible to direct photolysis by sunlight(SRC). The estimated photodegradation half-life in summer at 40 deg N latitude was 14 days on soil. The measured photodegradation half-life in water at 51.5 deg N was 3.3 days(4). Aquatic photodegradation is proposed to proceed via two routes. One is the formation of 5-hydroxy florasulam by oxidation of the methoxy group on the triazolopyrimidine ring to the hydroxyl group. An alternative route is through the loss of the difluorophenyl moiety by cleavage of the phenyl carbon-nitrogen bond, followed by the conversion of the methoxy group(5).

An estimated BCF of 3 was calculated in fish for florasulam(SRC), using a log Kow of -1.22(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of florasulam can be estimated to be 160(SRC). According to a classification scheme(2), this estimated Koc value suggests that florasulam is expected to have moderate mobility in soil. The pKa of florasulam is 4.54(3), indicating that this compound will partially exist in the anion form in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4). Florasulam, applied at a rate of 25.6 ng/g to Marcham (England; pH 7.7; sandy clay loam) and Naicam-Hoodoo (Canada; pH 7.5; clay loam) soils, exhibited apparent non-equilibrium sorption coefficients at 0 days after treatment of 0.1-0.5 L/kg and increased linearly with time to levels as high as 19-23 L/kg(5).

The Henry's Law constant for florasulam is estimated as 5.7X10-12 atm-cu m/mole(SRC) derived from its vapor pressure, 7.5X10-8 mm Hg(1), and water solubility, 6.36X10+3 mg/L(1). This Henry's Law constant indicates that florasulam is expected to be essentially nonvolatile from water and moist soil surfaces(3). Florasulam is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

Occupational exposure to florasulam may occur through inhalation and dermal contact with this compound at workplaces where florasulam is produced or used. (SRC)

Rapidly absorbed (following oral administration), with about 91% excretion within 24 hr, mainly in the urine, and mainly as unchanged florasulam.|In a dermal penetration study, (14)C-XDE-570 (Florasulam; 98-99% radiochemical purity as applied) was applied to the skin (12 sq cm) of Fischer 344 rats (4 males for each time point at each dose level). Nominal doses were 0.001 or 0.5 mg/sq cm skin. The high dose (EF-1343 commercial formulation) was included to assess exposure to mixer/loaders. The low dose (spray dilution, using an EF-1343 blank as a vehicle) represented a dose that was 2.39-fold more concentrated than the highest anticipated spray concentration for use on field crops, which was necessary in order to provide sufficient analytical sensitivity. The exposure duration was 24 hours, after which one group of 4 males for each dose level was sacrificed. The remaining 2 groups/dose were sacrificed at 48 or 72 hours post-application. Recovery of the applied dose (mass balance) was 100-103%. The majority of the dose was recovered in the skin swab (71-90% of the applied dose). Dermal absorption (based on the sum of residues in urine, feces, cage wash, tissues, residual carcass, and untreated skin) was only 0.13-0.45% of the applied dose and only 10-22% of the applied dose remained in the skin at the application site (considered potentially absorbable). Increasing the dose 200-fold resulted in only approximately 2-fold increase in absorption. Absorption increased 44% at 48 hr and 61% at 72 hr compared to 24 hr in the low dose groups; however, a time-dependent increase in absorption was not evident in the high dose groups. The absorbed dose was almost completely excreted in the urine at the low dose, but was found primarily in the urine, cage wash, and untreated skin at the high dose. The amount of radioactivity at the treatment site increased at 48 hours in the low dose, but did not decrease within 72 hours at either dose, suggesting that the compound in the skin was not readily absorbable. The compound isolated in the treated skin after 72 hours (including the 24 hour exposure period) would be absorbed in negligible amounts. The highest dermal absorption noted was 0.45% of the applied dose. This value is considered appropriate for use in risk assessment, with the appropriate uncertainty factors applied.|(14)C-XDE-570 (Florasulam; 99.3-99.5% radiochemical purity) in a suspension of 0.5% Methocel cellulose ethers was administered to 5 Fischer 344 rats/sex as a single gavage dose at 10 or 500 mg/kg bw. Additionally, 5 rats/sex were treated with 14 daily doses at 10 mg/kg bw/day of non-labeled florasulam followed by a single oral dose of (14)C-florasulam on Day 15. (14)C-Florasulam was uniformly labeled in the aniline ring for each of these test groups. In addition, 5 males were treated with a single gavage dose at 10 mg/kg bw with (14)C-florasulam (labeled at the 9 position in the triazolo-pyrimidine ring). All animals were killed 168 hours after the administration of the radiolabeled dose. Absorption was rapid and extensive. Approximately 90-93% of the dose was absorbed in the 10 mg/kg rats, and 82-86% was absorbed in the 500 mg/kg rats (based on the sum of radioactivity detected in the urine, tissues/carcass, and cage rinse). Peak plasma concentrations (Cmax) were achieved within 0.5-1 hour following dose administration at 10 or 500 mg/kg. Cmax in the plasma did not increase proportionally with dose, possibly indicating a saturation of the absorption and/or excretion mechanisms at the high dose. The apparent volume of distribution was increased at the high dose, possibly indicative of increased tissue binding. Total recoveries at 168 hours post-dose were 95.9-100.2% of the administered dose. Elimination was rapid. The administered dose was mostly eliminated within 12 hours in the urine (>80% of the dose at 10 mg/kg and >60% of the dose at 500 mg/kg). Total radioactivity found in the urine was approximately 90-92% of the dose following single or repeated low-dose treatment, and 81-85% of the dose following treatment at 500 mg/kg. Radioactivity in the feces accounted for another 5-7% at 10 mg/kg and 14-17% at 500 mg/kg. Thus, compared to the low dose, excretion of the high dose was slightly slower, and more of the compound was excreted in the feces. At 24 hours, <0.5% of the dose was found in expired air. By 24 hours post-dose, plasma levels had declined to <0.1ug eq/g plasma in both sexes at 10 mg/kg and <5.0 ug eq/g plasma in both sexes at 500 mg/kg. The highest residue levels were observed in the skin (single dose) and carcass (repeated dose), but the mean recovery of radioactivity in the tissues/carcass at sacrifice was <0.6% of the dose.

(14)C-XDE-570 (Florasulam; 99.3-99.5% radiochemical purity) in a suspension of 0.5% Methocel cellulose ethers was administered to 5 Fischer 344 rats/sex as a single gavage dose at 10 or 500 mg/kg bw. Additionally, 5 rats/sex were treated with 14 daily doses at 10 mg/kg bw/day of non-labeled florasulam followed by a single oral dose of (14)C-florasulam on Day 15. (14)C-Florasulam was uniformly labeled in the aniline ring for each of these test groups. In addition, 5 males were treated with a single gavage dose at 10 mg/kg bw with (14)C-florasulam (labeled at the 9 position in the triazolo-pyrimidine ring). All animals were killed 168 hours after the administration of the radiolabeled dose. ... Identified compounds accounted for 87.6-91.6% of the administered dose in each group. In each group, the following compounds were isolated: parent accounted for 77.7-85.0% dose, OH-phenyl- XR-570 (exact position of hydroxyl group not determined) accounted for 3.1-9.0% dose, OH-phenyl-XR-570 sulfate conjugate accounted for 2.8-3.7% dose, and 2 unidentified metabolites accounted for < or = 0.32% dose. In the high dose, more of the parent was isolated in the feces and less in the urine compared to the low dose.

Florasulam is a selective triazolopyrimidine sulfonanilide post-emergent herbicide. The pesticidal mode of action (MOA) is through inhibition of acetolactate synthase (ALS) in plants. ALS is found in the chloroplast where it catalyses branch chained amino acid biosynthesis. Inhibition of ALS results in inhibition of plant cell division, decreased plant growth, and ultimately, plant death.

/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/|/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/|/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/

florasulam

Suspension concentrate|Premix Partners: Clodinafop-propargyl; Fluroxypyr; MCPA; Pinoxaden; Pyroxsulam|Orion Herbicide (Syngenta Crop Protection, LLC) MCPA, 2-ethylhexyl ester 42.25%, Primus 0.39%|Axial TBC Herbicide (Syngenta Crop Protection, LLC) Primus 0.75%, Pinoxaden 9%|For more Formulations/Preparations (Complete) data for Florasulam (13 total), please visit the HSDB record page.

The WHO Recommended Classification of Pesticides by Hazard identifies florasulam as unlikely to present an acute hazard in normal use; Main Use: herbicide.

Adequate enforcement methodology (capillary gas chromatography with mass selective detection (GC/MSD) is available to enforce the tolerance expression.

Agrochemicals -> Herbicides|Herbicides|Environmental transformation -> Pesticides (parent, predecessor)

Florasulam has known environmental transformation products that include 5-(aminosulfonyl)-1H-1,2,4-triazole-3-carboxylic acid, N-(2,6-difluorophenyl)-5-aminosulfonyl-1H-1,2,4-triazole-3-carboxylic acid, and N-(2,6-difluorophenyl)-8-fluoro-5-hydroxy(1,2,4)triazolo(1,5-c)pyrimidine-2-sulfonamide.|Florasulam has known environmental transformation products that include 5-OH Florasulam, ASTCA, DFP-ASTCA, DFP-TSA, and TSA.