Triasulfuron

Pesticide -> EPA IRIS

Herbicides

Active substance -> EU Pesticides database: Not approved

Environmental transformation -> Pesticides (parent, predecessor)

Pesticide (Triasulfuron) -> USDA PDB

Pesticide

log Kow = 1.1 (pH 5.0), -0.59 (pH 6.9), -1.8 (pH 9.0) at 25 °C

2.04

In water, 1.5 g/L (pH 7) at 20 °C

In water, 32 mg/L (pH 5), 815 mg/L (pH 7), 13,500 mg/L (pH 8.2) at 25 °C

Solubility (g/L at 25 °C): Acetone 14, dichloromethane 36, ethyl acetate 4.3); Solubility (mg/L at 25 °C): ethanol 420, n-octanol 130, n-hexane 0.04, toluene 300

178.1 °C (decomposes)

Melting point: 186 °C

Vapor pressure: 7.5X10-13 mm Hg at 20 °C

Vapor pressure: 2.25X10-10 mm Hg at 25 °C (based on the Knudsen diffusivity (m sq/sec) measured value for triasulfuron's close analog Chlorsulfuron)

<1.5X10-8 mm Hg at 25 °C (OECD Guideline Method 104)

Positive

2.17

2.7

Agilent XCT

Electrospray ionization

formic acid (5.3nM)

Warning

H400: Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

P273, P391, and P501 (click each P-code to see the statement)

Warning

H400 (100%): Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

P273, P391, and P501 (click each P-code to see the statement)

Commission Regulation (EU) No 1141/2010

Triasulfuron is listed in the dataset of EPA Human Health Benchmarks for Pesticides under the Safe Drinking Water Act (40 eCFR 141)

00/66/EC, 2010/77/EU, Reg (EU) 2015/408, Reg. (EU) 2015/1885, Reg. (EU) 2016/864, Reg. (EU) No 540/2011

REACH registered substance: Triasulfuron (EC: 617-298-9)

Aquatic Acute 1 (100%)

Hazardous to the aquatic environment (acute) - category 1

Aquatic Acute 1

Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.

Advice for firefighters: Wear self-contained breathing apparatus for firefighting if necessary.

ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Use personal protective equipment. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided. Methods and materials for containment and cleaning up: Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.

SRP: 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 air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.

Product: Offer surplus and non-recyclable solutions to a licensed disposal company. Contact a licensed professional waste disposal service to dispose of this material. Contaminated packaging: Dispose of as unused product.

ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Use personal protective equipment. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided.

Precautions for safe handling: Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Provide appropriate exhaust ventilation at places where dust is formed.

Appropriate engineering controls: Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday.

Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants. Ensure that the local ventilation moves the contaminant away from the worker.

Eye/face protection: Safety glasses with side-shields conforming to EN 166. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).

Handle with gloves.

Body Protection: Complete suit protecting against chemicals. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.

Respiratory protection: For nuisance exposures use type P95 (US) or type P1 (EU EN 143) particle respirator. For higher level protection use type OV/AG/P99 (US) or type ABEK-P2 (EU EN 143) respirator cartridges. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).

LC50; Species: Colinus virginianus (Northern Bobwhite Quail) age 14 days; diet >5000 ppm for 8 days /94.5% purity/

LC50; Species: Anas platyrhynchos (Mallard Duck) diet >5000 ppm for 8 days /94.5% purity/

LD50; Species: Anas platyrhynchos (Mallard Duck) oral via capsule >2150 mg/kg /94.5% purity/

LD50; Species: Colinus virginianus (Northern Bobwhite Quail) age 175 days; oral via capsule >2150 mg/kg /94.5% purity/

For more Ecotoxicity Values (Complete) data for Triasulfuron (17 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), measured Koc ranges of 7-25(2) and 51.6-190.6(3) in a variety of soils, indicate that triasulfuron is expected to have very high to moderate mobility in soil(SRC). The pKa of triasulfuron is 4.64(4), indicating that this compound will exist partially in anion form at pH 5 and almost entirely in the anion form at pH 7-9 in the environment(SRC) and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(5). Some studies indicate adsorption in soil can be effected by humic acids and pH(6,7) while other studies found that adsorption of triasulfuron was not pH dependent(8). Volatilization of non-ionized triasulfuron from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of <2.5X10-10 atm-cu m/mole(SRC), derived from its vapor pressure, <1.5X10-8 mm Hg(4), and water solubility, 32-13500 mg/L at pH5-8.2(4). Triasulfuron in anion form will not volatilize. Triasulfuron is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(SRC). Triasulfuron did not volatilize from soil or plant surfaces during photolytic degradation tests(2). Triasulfuron was found to be not readily biodegradable in sediment-water degradation studies with biodegradation half-lives ranging from 30-245 days(2). Measured half-lives of triasulfuron in microbially active soils (pH 6.5 or 7.2) were found to be four times faster than those in sterile soil(9). Triasulfuron is susceptible to aqueous hydrolysis in moist acidic soils; hydrolysis half-life is about 30 days at pH 5 and 20 °C(3). Triasulfuron absorbs at wavelengths >290 nm(3) and is susceptible to direct photolysis by sunlight on soil surfaces(2). Reported half-lives in field dissipation studies ranged from 3-48 days (mean of 19 days), 8-59 days and 10-87 days(8). and 10-87 days(3).

FIELD STUDY: Herbicides are essential in agricultural systems for maintaining crop yields, as weeds compromise grain production. Furthermore, the application of organic amendments to soil is an increasingly frequent agricultural practice for avoiding irreversible soil degradation. However, this practice could modify the behaviour of the herbicides applied, with implications for their absorption by weeds. This study evaluated the dissipation, persistence and mobility of the herbicides triasulfuron and prosulfocarb in a sandy clay loam soil unamended and amended with green compost (GC) in a field experiment using single or combined commercial formulations of both herbicides. The study was carried out in experimental plots (eight treatments x three replicates) corresponding to unamended soil and soil amended with GC, untreated and treated with the herbicide formulations Logran Tr, Auros Tr and Auros Plus Tr over 100 days. The half-life (DT50) of triasulfuron applied individually was 19.4 days, and increased in the GC-amended soil (46.7 days) due to its higher adsorption by this soil, although non-significant differences between DT50 values were found when it was applied in combination with prosulfocarb. Prosulfocarb dissipated faster than triasulfuron under all the conditions assayed, but non-significant differences were observed for the different treatments. The analysis of the herbicides at different soil depths (0-50 cm) after their application confirmed the leaching of both herbicides to deeper soil layers under all conditions, although larger amounts of residues were found in the 0-10 and 10-20 cm layers. The application of GC to the soil increased the persistence of both herbicides, and prevented the rapid leaching of triasulfuron in the soil, but the leaching of prosulfocarb was not inhibited. The influence of single or combined formulations was observed for triasulfuron, but not for prosulfocarb. The results obtained highlight the interest of obtaining field data to design rational joint applications of GC and herbicides to prevent the possible decrease in their effectiveness for weeds or the risk of water contamination.

AQUATIC FATE: Based on a classification scheme(1), measured Koc ranges of 7-25(2) and 51.6-190.6(3) indicate that triasulfuron is not expected to adsorb to suspended solids and sediment(SRC). A pKa of 4.64(4) indicates this compound will exist partially in anion form at pH 5 and almost entirely in the anion form at pH 7-9 in the environment(SRC), and volatilization of the anion form from water surfaces is not expected to be an important fate process(SRC). Volatilization from water surfaces is also not expected of the non-ionized form(3) based upon an estimated Henry's Law constant of <2.5X10-10 atm-cu m/mole(SRC), derived from its vapor pressure, <1.5X10-8 mm Hg(4), and water solubility, 32-13500 mg/L at pH5-8.2(4). According to a classification scheme(5), an estimated BCF of 1(SRC), from its log Kow of 1.10(4) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Triasulfuron was found to be not readily biodegradable in sediment-water degradation studies with biodegradation half-lives ranging from 30-245 days(2). The USDA Pesticide Properties Database lists the hydrolysis rate of triasulfuron as "Stable" at pH 7-9 (20 °C) and 0.023/day (half-life of 30 days) at pH 5 (20 °C)(3). Hydrolysis half-lives at 25 °C were 7.78 days (pH 4), 13.8 days (pH 5), 27.1 days (pH 6), 492 days (pH 7) and 387 days (pH 9)(7). Triasulfuron absorbs at wavelengths >290 nm(2) and, therefore, may be susceptible to direct photolysis by sunlight(SRC). At 10 ppm in aqueous solution at 20 °C, triasulfuron had a 3 hour photo-stability half-life when irradiated with a mercury vapor lamp(2).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), triasulfuron, which has a vapor pressure of <1.5X10-8 mm Hg at 25 °C(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase triasulfuron may be removed from the air by wet and dry deposition(SRC). Triasulfuron absorbs at wavelengths >290 nm(3) and, therefore, may be susceptible to direct photolysis by sunlight(SRC). Triasulfuron photodegrades in aqueous solution exposed to sunlight(4).

IDENTIFICATION AND USE: Triasulfuron is a fine white powder. it is used as a selective herbicide pre- and post-emergence for the control of annual broad-leaved weeds in wheat, barley, and triticale. HUMAN STUDIES: There are no data available. ANIMAL STUDIES: In rats fed triasulfuron for 90 days reduced body weight and kidney toxicity observed at 10,000 ppm. In mice fed triasulfuron for 2 years, centrilobular hepatocytomegaly was observed in male mice receiving 1000, 5000, and 10,000 ppm and in females receiving 10,000 ppm. Increased centrilobular degeneration, focal accumulation of inflammatory cells, microgranulomas, and pigment depositions were also observed in the liver of 10,000-ppm males. In dogs, fed triasulfuron in the diet for 1 year, effects seen at 5000 ppm include liver vacuolization, Kupffer cell pigment, lymphoid hyperplasia, anemia, increased relative spleen, kidney (females), pituitary (females), and liver weights, and increased severity of prostate cystic hyperplasia in males. In developmental study in rats, reductions in body weight were noted in F1a and F2a pups. No developmental effects were observed in rabbits. The genotoxicity of trisulfuron was demonstrated in the wing spot test of Drosophila melanogaster. ECOTOXICITY STUDIES: For aquatic organisms triasulfuron photoproducts were less toxic than the parent compound.

/AQUATIC SPECIES/ The present study aimed to compare the sensitivity of larvae of the gilthead seabream (Sparus aurata), a valuable fish species of the Spanish South Atlantic littoral, with the extensively used Microtox test on a commercial herbicide formulation containing terbutryn (59.4%) and triasulfuron (0.6%). To this purpose, mortality displayed by endogenous feeding S. aurata larvae exposed during 72 hr post-hatching to nominal concentrations of the commercial formulation and bioluminescence of the marine bacterium Vibrio fischeri were compared. Histomorphological changes were also studied. Clearly, the S. aurata assay was the more sensitive indicator of toxicity for this herbicide. The 72-hr concentration lethal to 50% of the individuals (LC(50)) found for yolk sac larvae was 1.41 mg/L. This value was more than one order of magnitude below the 15-min EC(50) found for V. fischeri (15.94 mg/L). Growth of the larvae was not significantly affected by a terbutryn-triasulfuron mixture at concentrations up to 1.56 mg/L, the maximum at which there was some proportion of survival.

/AQUATIC SPECIES/ The toxicological effects of the sulfonylurea herbicide triasulfuron and its photoproducts were assessed on four aquatic organisms. Toxicity varied with tested organism and with triasulfuron irradiation time. Triasulfuron and its photoproducts had no significant effects on the crustacean (Cladocera) Daphnia magna (causing 50% effective concentration [EC50] [48 hr] = 49 +/- 1 mg/L) and the marine bacteria Vibrio fischeri (EC50 [30 min] > 100 mg/L). In contrast, primary producers (the duckweed Lemna minor, the microalgae Pseudokirchneriella subcapitata, and Chlorella vulgaris) were very sensitive to triasulfuron (EC50s < 11 microg/L). For these organisms, triasulfuron photoproducts were less toxic than the parent compound but the residual toxicity observed still represented a potential environmental hazard.

EPA has released the Interactive Chemical Safety for Sustainability (iCSS) Dashboard. The iCSS Dashboard provides an interactive tool to explore rapid, automated (or in vitro high-throughput) chemical screening data generated by the Toxicity Forecaster (ToxCast) project and the federal Toxicity Testing in the 21st century (Tox21) collaboration. /The title compound was tested by ToxCast and/or Tox21 assays/[USEPA; ICSS Dashboard Application; Available from, as of August 9, 2018: http://actor.epa.gov/dashboard/]

Triasulfuron

Hepatic

1 x 10 ^-2 mg/kg-day

Soil adsorption studies using 9 soils (organic content 0.6-25%, pH 6.2-7.8) determined a Koc range of 7-25(1). Using three Italian soils (organic matter 1.3, 4.4 and 6.3%), measured Kd values were 0.46, 1.13 and 6.43 respectively(2); these correspond to Koc values of 48, 61 and 173 respectively(SRC). Triasulfuron Koc values of 9.2 and 9.6 were determined in a loam soil and a clay loam soil, respectively(3). The USDA Pesticide Properties Database list a Koc range of 51.6 to 190.6 for triasulfuron with a recommended value of 105(4). According to a classification scheme(5), these Koc values suggest that triasulfuron is expected to have very high to moderate mobility in soil. The content of humic acids and soil pH can effect the soil adsorption of triasulfuron(2,6), although some laboratory studies found that adsorption of triasulfuron and its metabolite (triazine amine) was not pH dependent(7). Mobility tests in three alkaline cropping soils in Australia found triasulfuron to be mobile as leaching exceeded an 80 cm soil depth(8).

Triasulfuron's production may result in its release to the environment through various waste streams; its use as a herbicide to control broad-leaved weeds pre- and post-emergence in wheat, barley and triticale(1) will result in its direct release to the environment(SRC).

AEROBIC: Laboratory studies in 4 soils at 20 °C found triasulfuron dissipation half-lives of 33-76 days with triazine amine as a metabolite(1). A dissipation half-life of 49 days was observed in laboratory tests at 10 °C(1). In 6 soils at 25 °C in laboratory tests, 90% triasulfuron dissipation occurred in 127-349 days(1). A review of reliable field studies from 17 sites (US, Switzerland, France, Canada, Germany and Brazil) determined a triasulfuron dissipation half-life range of 3-48 days (one exception, 83 days), a mean dissipation half-life of 19 days and 90 percentile of 38 days(1); 90% dissipation ranged from 53-300 days with a mean of 70 days(1). Triasulfuron was classified as having moderate to medium persistance based on studies which indicated biphasic kinetics with half lives of 15-48 days at 20 °C and 8-59 days in Europoean field studies(2). The USDA Pesticide Properties Database lists a triasulfuron field dissipation half-life of 10-87 days(3).

ANAEROBIC: Laboratory studies at 20 °C found a triasulfuron dissipation half-life of about 280 days under anaerobic conditions(1).

Cytochrome P450 monooxygenases play paramount roles in the detoxification of herbicides as well as in the synthesis of lignins, flavonoids, and phenolic acids. Biochemical analysis of triasulfuron metabolism in maize (Zea mays) seedlings has demonstrated that the P450(s) responsible for detoxification of this herbicide is induced by naphthalic anhydride (NA), a plant safener, and by triasulfuron, the herbicide itself. Induction studies conducted with seedlings of different ages suggest that two separate response pathways modulate this P-450 activity. Induction by NA is independent of the developmental age of the seedlings up to 6.5 d; induction by triasulfuron is tightly modulated with respect to developmental age in that triasulfuron metabolism can be induced by triasulfuron in young (2.5 d) but not older (6.5 d) seedlings. Induction by NA administered in combination with triasulfuron synergistically enhances triasulfuron metabolism in younger seedlings to levels substantially above that obtained with either herbicide or safener treatment alone. In older seedlings, NA plus triasulfuron treatment induces triasulfuron metabolism to only the level of NA treatment alone, indicating again that the induction cascade responding to triasulfuron is nonfunctional in later development. MnCl2 studies indicate that the triasulfuron insensitivity of older seedlings does not result from a general limitation in the inducibility of this P-450 detoxification system but rather from specific limitations in the triasulfuron-response pathway.

For triasulfuron (USEPA/OPP Pesticide Code: 128969) ACTIVE products with label matches. /SRP: Registered for use in the USA but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./

... Selective herbicide used pre- and post-emergence for the control of annual broad-leaved weeds in wheat, barley, and triticale.

Herbicide

This is a man-made compound that is used as a pesticide.

Triasulfuron is produced by reaction of 2- chloroethoxyphenylsulfamoyl chloride with 2- amino-4-methoxy-6-methyl-1,3,5-triazine.

Preparation: W. Meyer, W. Fory, European Patent Office patent 44808; eidem, United States of America patent 4514212 (1982, 1985 both to Ciba-Geigy)

Triasulfuron Technical (Syntenta Crop Protection, LLC): Active ingredient: triasulfuron 92.0%.

Custom-Pak Amber Herbicide (Syntenta Crop Protection, LLC): Active ingredient: triasulfuron 75.0%.

Rave Herbicide (Syntenta Crop Protection, LLC): Active ingredient: dicamba, sodium salt 55.0% and triasulfuron 8.8%.

Wettable powders.

For more Formulations/Preparations (Complete) data for Triasulfuron (6 total), please visit the HSDB record page.