オルトスルファムロン

LC50; Species: Oncorhynchus mykiss (Rainbow trout, juvenile); Conditions: freshwater, static; Concentration: >122 mg/L for 96 hr /98.56% a.i./

LC50; Species: Lepomis macrochirus (Bluegill sunfish, juvenile); Conditions: freshwater, static; Concentration: >142 mg/L for 96 hr /98.56% a.i./

EC50; Species: Daphnia magna (Water flea, neonate); Conditions: freshwater, static; Concentration: >97.3 mg/L for 48 hr; Effect: immobilization (lethality) /98.54% a.i./

LC50; Species: Procambarus clarkia (Crayfish, juvenile); Conditions: freshwater, static; Concentration: >129 mg/L for 96 hr /98.56% a.i./

For more Ecotoxicity Values (Complete) data for Orthosulfamuron (27 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 10(SRC), determined from a structure estimation method(2), indicates that orthosulfamuron is expected to have very high mobility in soil(SRC). Volatilization of orthosulfamuron from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 7.4X10-10 atm-cu m/mole(SRC), based upon its vapor pressure, 8.4X10-7 mm Hg(3), and water solubility, 629 mg/L(3). Orthosulfamuron is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(3). No biodegradation data were located for orthosulfamuron in soil but aerobic degradation is expected to be the major route of dissipation in alkaline paddy water(4).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 10(SRC), determined from a structure estimation method(2), indicates that orthosulfamuron 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 7.4X10-10 atm-cu m/mole(SRC), derived from its vapor pressure, 8.4X10-7 mm Hg(4), and water solubility, 629 mg/L(4). Orthosulfamuron is expected to undergo hydrolysis in the environment and has reported half-lives of 8 hours, 24 days and 228 days at pH 4, 7 and 9, respectively, at 25 °C(4). According to a classification scheme(5), an estimated BCF of 3.4(SRC), from its log Kow of 1.31(4) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Orthosulfamuron's major route of degradation in acidic to neutral rice paddy water is hydrolysis, with a half-life of hours to days(7). Aerobic biodegradation is the major route of degradation in alkaline rice paddy water, with a half-life of weeks to months(7). Both routes of degradation are expected at similar rates in paddy water at neutral pH(7).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), orthosulfamuron, which has a vapor pressure of 8.4X10-7 mm Hg at 20 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase orthosulfamuron 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 35 minutes(SRC), calculated from its rate constant of 2.2X10-10 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase orthosulfamuron may be removed from the air by wet or dry deposition(SRC). Orthosulfamuron contains chromophores that absorb at wavelengths >290 nm(4) and therefore may be susceptible to direct photolysis by sunlight(SRC).

/BIRDS and MAMMALS/ Chronic studies of the reproductive toxicity of orthosulfamuron in mallard duck and bobwhite quail administered orthosulfamuron TGAI for approximately 21 weeks. ...Results of both studies showed no treatment-related effects on adult bird mortality, food consumption, body weight, clinical signs, or reproductive endpoints at the highest dietary concentration tested (NOAEC = 1280 mg a.i./kg diet). In addition, no clinical signs or treatment-related effects in offspring survival or body weight were observed at the highest dietary concentration tested in these studies (1280 mg a.i/kg diet).

/AQUATIC SPECIES/ The acute toxicity of technical grade orthosulfamuron to freshwater fish was evaluated in two species, with 96-hour LC50 values of >122 mg a.i./L in rainbow trout and >142 mg a.i./L in bluegill sunfish. No mortalities were observed in controls or treated groups for both studies. Based on these results, orthosulfamuron is categorized as practically nontoxic to freshwater fish on an acute exposure basis.

/AQUATIC SPECIES/ The acute toxicity of technical grade orthosulfamuron to estuarine/marine fish was evaluated in the sheepshead minnow. The study reported a 96-hour LC50 >123 mg a.i./L, indicating that orthosulfamuron was practically nontoxic to estuarine/marine fish on an acute exposure basis. No sublethal effects were observed in sheepshead minnow exposed up to 123 mg a.i./L.

/AQUATIC SPECIES/ Acute toxicity tests with estuarine/marine invertebrates exposed to technical grade orthosulfamuron were conducted in eastern oyster and mysid shrimp. No effect on shell deposition or increased mortality were observed in an acute toxicity (96-hour) test in the eastern oyster exposed to orthosulfamuron TGAI, yielding a 96-hour EC50 >97 mg a.i./L. These results indicate that orthosulfamuron is characterized as slightly toxic to estuarine/marine mollusks. An acute toxicity study of orthosulfamuron in the mysid shrimp reported a 96-hour LC50 >122 mg a.i./L, indicating that orthosulfamuron is practically nontoxic to estuarine/marine invertebrates on an acute exposure basis; no sublethal effects were observed.

For more Ecotoxicity Excerpts (Complete) data for Orthosulfamuron (12 total), please visit the HSDB record page.

Using a structure estimation method based on molecular connectivity indices(1), the Koc of orthosulfamuron can be estimated to be 10(SRC). According to a classification scheme(2), this estimated Koc value suggests that orthosulfamuron is expected to have very high mobility in soil.

An estimated BCF of 3.4 was calculated in fish for orthosulfamuron(SRC), using a log Kow of 1.31(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).

The Henry's Law constant for orthosulfamuron is estimated as 7.4X10-10 atm-cu m/mole(SRC) derived from its vapor pressure, 8.4X10-7 mm Hg(1), and water solubility, 629 mg/L(1). This Henry's Law constant indicates that orthosulfamuron is expected to be essentially nonvolatile from water or moist soil surfaces(2). Orthosulfamuron is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ In a 90-day subchronic oral toxicity study, IR5878 (98.0% a.i.) was administered to ten Han Wistar rats/sex/dose in the diet at dose levels of 0, 250, 1500, and 9000 ppm (equivalent to 0, 19, 113, and 706 mg/kg bw/day, respectively, for males and to 0, 22, 131, and 773 mg/kg bw/day, respectively, for females). Concurrently, a recovery group of five Han Wistar rats/sex/dose were administered either 0 or 9000 ppm (equivalent to 0 or 706 mg/kg bw/day, respectively, for males and to 0 or 773 mg/kg bw/day, respectively, for females) during the 90-day study period and were then maintained for an additional four weeks on the control diet. There were no compound-related effects on mortality, body weights, body weight gains, food consumption, neurological observations and measurements, hematology, clinical chemistry, or gross pathology. Compared to controls, an increase in dorsal hair loss was seen in females, but this finding is common. Other treatment-related effects (transient increases in liver weight and hepatocellular hypertrophy in high-dose males compared to controls) indicate a minimal, adaptive response in the liver following exposure to IR5878 that is not considered adverse. The LOAEL was not identified in this study (>706 mg/kg/day for males and >773 mg/kg/day for females). The NOAEL is the highest dose tested in this study (9000 ppm), which was equivalent to 706 mg/kg/day for males and 773 mg/kg/day for females.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ In a 90-day subchronic oral toxicity study, IR5878 (98.0% a.i.) was administered to ten CD-1 mice/sex/dose in the diet at dose levels of 0, 250, 1250, and 6000 ppm (equivalent to 0, 36, 187, and 865 mg/kg bw/day, respectively, for males and to 0, 47, 228, and 1096 mg/kg bw/day, respectively, for females). There were no compound-related effects on clinical signs, mortality, body weights, clinical chemistry, gross pathology, or histopathology. Compared to controls, slight decreases in food consumption, MCH, and MCV in high-dose females and slight decreases in the lymphocyte count of high-dose males were noted, but these changes were not biologically significant. The LOAEL was not identified in this study (>865 mg/kg/day for male mice and >1096 mg/kg/day for females). The NOAEL is the highest dose tested in this study (6000 ppm), which was equivalent to 865 mg/kg/day for male mice and 1096 mg/kg/day for females. Dosing in this study is considered adequate because the highest dose tested is sufficiently close to the limit dose of 1000 mg/kg/day.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ In a 28-day dermal toxicity study, Orthosulfamuron (IR5878; 98.56% a.i.) was moistened with deionized water and applied by semi-occlusive dressing to the shaved intact skin of 10 Sprague-Dawley rats/sex/dose at dose levels of 0 or 1000 mg/kg bw/day (limit dose), 6 hours/day for 7 days/week during a 4-week period. No adverse compound-related effects were observed in mortality, clinical signs, dermal effects, body weight, body weight gain, food consumption, food conversion efficiency, hematology, clinical chemistry, ophthalmology, absolute or relative organ weights, or gross and histological pathology. The LOAEL was not determined. The NOAEL is 1000 mg/kg/day (limit dose).

The rate constant for the vapor-phase reaction of orthosulfamuron with photochemically-produced hydroxyl radicals has been estimated as 2.2X10-10 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 35 minutes at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Orthosulfamuron is expected to undergo hydrolysis in the environment and has reported half-lives of 8 hours, 24 days and 228 days at pH 4, 7 and 9, respectively, at 25 °C(2). Orthosulfamuron's major route of degradation in acidic to neutral rice paddy water is hydrolysis, with a half-life of hours to days(3). Orthosulfamuron contains chromophores that absorb at wavelengths >290 nm(4) and therefore may be susceptible to direct photolysis by sunlight(SRC).

Orthosulfamuron's production may result in its release to the environment through various waste streams; its use as a herbicide will result in its direct release to the environment. If released to air, a vapor pressure of 8.4X10-7 mm Hg at 25 °C indicates orthosulfamuron in both the vapor and particulate phases in the atmosphere. Vapor-phase orthosulfamuron will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 35 minutes. Particulate-phase orthosulfamuron will be removed from the atmosphere by wet or dry deposition. Orthosulfamuron contains chromophores that absorb at wavelengths >290 nm and therefore may be susceptible to direct photolysis by sunlight. If released to soil, orthosulfamuron is expected to have very high mobility based upon an estimated Koc of 10. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 7.4X10-10 atm-cu m/mole. Orthosulfamuron's major route of degradation in acidic to neutral rice paddy water is hydrolysis, with a half-life of hours to days. Aerobic biodegradation is the major route of degradation in alkaline rice paddy water, with a half-life of weeks to months. Both routes of degradation are expected at similar rates in paddy water at neutral pH. If released into water, orthosulfamuron is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. An estimated BCF of 3.4 suggests the potential for bioconcentration in aquatic organisms is low. Orthosulfamuron is expected to undergo hydrolysis in the environment and has reported half-lives of 8 hours, 24 days and 228 days at pH 4, 7 and 9, respectively, at 25 °C. Occupational exposure to orthosulfamuron may occur through inhalation of dust and dermal contact with this compound at workplaces where orthosulfamuron is produced or used. (SRC)

For orthosulfamuron (USEPA/OPP Pesticide Code: 108209) 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./

Herbicides (pyrimidinylsulfonylurea herbicides)

For use on rice

Early post-emergence control of annual and perennial broad-leaved weeds, sedges and barnyard grass, in dry-seeded rice, water-seeded rice, transplanted rice, cereals, pastures and sugar cane.

Orthosulfamuron Technical (Isagro S.P.A.) 99% Orthosulfamuron

IR5878 50 WG (Isagro S.P.A.) 50% Orthosulfamuron

IR5878 0.5 GR (Isagro S.P.A.) 0.5% Orthosulfamuron

Strada XT (Isagro S.P.A.) 50% Orthosulfamuron, 75% Quinclorac

Orthosulfamuron is formulated as both a water dispersible granule (IR5878 50 WG) and a granule (IR5878 0.5 GR).