Cloransulam-Methyl

LD50; Species: /Colinus virginianus/ (Bobwhite quail) >2250 mg/kg bw

LC50; Species: /Colinus virginianus/ (Bobwhite quail) diet >5620 ppm for 5 days /Conditions of bioassay not specified/

LC50; Species: /Anas platyrhynchos/ (Mallard duck) diet >5620 ppm for 5 days /Conditions of bioassay not specified./

LD50; Species: /Apis mellifera/ (Honey bee) contact >25 ug ai/bee

For more Ecotoxicity Values (Complete) data for CLORANSULAM-METHYL (24 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values of 12 to 915(2-3) indicate that cloransulam-methyl is expected to have very high to low mobility in soil(SRC). The pKa of cloransulam-methyl is 4.81(4), indicating that this compound will exist almost entirely 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(5). Volatilization from moist soil is not expected because the compound exists as an anion and anions do not volatilize. Cloransulam-methyl is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure of 3.0X10-16 mm Hg(4). A photodegradation half-life of 13 days was reported for cloransulam-methyl in moist soil(6). Biodegradation of cloransulam-methyl in soil may be important based upon reported half-lives of 9 to 21 days(7). In field dissipation studies, cloransulam-methyl had reported half-lives ranging from 4.2 to 24.1 days(6).

AQUATIC FATE: Based on a classification scheme(1), Koc values of 12 to 915(2-3), indicate that cloransulam-methyl is expected to adsorb to suspended solids and sediment(SRC). A pKa of 4.81(4) indicates cloransulam-methyl will exist almost entirely 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. According to a classification scheme(5), an estimated BCF of 3(SRC), from its log Kow of -0.365(4) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is low(SRC). An anaerobic aquatic biodegradation rate of 0.043/day with a half-life of 16 days was reported for cloransulam-methyl(8). Based upon an aqueous photodegradation half-life of 54 minutes, cloransulam-methyl may photodegrade rapidly in shallow sunlit water(8). Hydrolysis of cloransulam-methyl may be expected based upon a reported half-life of 10 days in natural water(7).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), cloransulam-methyl, which has a vapor pressure of 3.0X10-16 mm Hg at 25 °C(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase cloransulam-methyl may be removed from the air by wet or dry deposition(SRC).

/AQUATIC SPECIES/ No mortality or sublethal effects from cloransulam-methyl exposure were reported for the grass shrimp; the 96-hr LC50 was >121 mg a.i./L. In contrast, effects on mean shell deposition to the Eastern oyster were reported at the limit concentration (111 mg a.i./L) tested. Mean shell deposition was decreased 18% compared to the negative control, and no additional adverse effects were noted. The 96-hr EC50 for Eastern oyster was >111 mg a.i./L (most sensitive estuarine/marine invertebrate acute toxicity endpoint) and the 96-hr NOAEC was < 111 mg a.i./L based on mean shell deposition.

Assessment in the field indicates little movement of cloransulam-methyl into the soil profile; residues are contained in the upper 12 to 18 inches of soil(1). Observed cloransulam-methyl Koc values ranged from 54.4 to 915 after three months incubation on six different soil types(1); greater adsorption at low versus high soil pH(1); sorption tends to increase with time associated with the soil(1). In a 55-day incubation study using 16 different soil types(2), time-averaged Koc values ranged from 12 to 262; apparent sorption (as measured by Kd) was observed to generally increase by as much as 10-fold over time(2). According to a classification scheme(3), these Koc values suggest that cloransulam-methyl is expected to have very high to low mobility in soil. Field studies conducted in Wisconsin, Mississippi, Indiana and North Carolina between 1993 and 1995 found that cloransulam-methyl exhibited low mobility in soil(4); cloransulam-methyl was rarely detected below 30 cm depth and was generally confined in the upper 5 cm(4); even with extreme leaching conditions at the WI and NC sites, cloransulam-methyl did not leach below 30 cm(4).

AEROBIC: Aerobic studies using Cecil loamy sand and Hanford loam soils incubated at 25 °C in the dark observed 14C labeled cloransulam-methyl half-lives of 9 and 13 days, respectively, using a biphasic pattern model(1). Using a first-order model, respective half-lives were 16 and 21 days(1). Degradation rates decreased about 10-fold when the soils were incubated at 5 °C or when sterilized by gamma-irradiation(1). Evolved 14CO2 accounted for up to 10% of applied 14C; other metabolites included cloransulam, 5-hydroxycloransulam-methyl and 5-hydroxycloransulam(1). Influence of temperature on the mineralization rate was dependent upon the location of the radio-label within the cloransulam-methyl molecule, suggesting that distinct groups of microorganisms degrade different parts of the molecule at different temperatures(2). Mineralization of radio-labeled cloransulam-methyl measured by 14CO2 was less in sterilized soil as compared to non-sterile soil(2).

ANAEROBIC: An anaerobic aquatic biodegradation rate of 0.043/day with a half-life of 16 days was reported for cloransulam-methyl(1).

An estimated BCF of 3 was calculated in fish for cloransulam-methyl(SRC), using a log Kow of -0.365(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).

A pKa of 4.81(1) indicates cloransulam-methyl will exist almost entirely in the anion form at pH values of 5 to 9 and therefore volatilization from water and moist soil surfaces is not expected to be an important fate process. Cloransulam-methyl is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor of 3.0X10-16 mm Hg(1).

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ 90-day dietary (mice): NOEL= 50 mg/kg/day (males). LOEL= 100 mg/kg/day for males based on increased levels of alkaline phosphatase and increased liver weights and an increase in the size of hepatocytes.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ 21-day dermal (Rabbit): Dermal Irritation NOEL >or= 1000 mg/kg/day. Systemic NOEL = 500 mg/kg/day. Systemic LOEL = 1000 mg/kg/day based on decreased red cell count, hemoglobin and hematocrit, anisocytosis and macrocytosis of red cells for females.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ In the Fischer 344 (F344) rat, dosages of 100-1000 mg/kg/day for 2 weeks produced slight decreases in red blood cell parameters and urine specific gravity in males, and slightly increased cecal and liver weights in females at 1000 mg/kg/day. The no-observed-effect level (NOEL) was 500 mg/kg/day. Dosages of 100-1000 mg/kg/dy for 13 weeks produced treatment-related kidney changes consisting of very slight to moderate hypertrophy of collecting tubule epithelial cells and/or slight vacuolation of the renal proximal tubular epithelium consistent with fatty changes in all dosage groups. Decreased body weight gain and feed consumption, very slight hepatocellular vacuolation, and slight thyroid follicular hypertrophy were also seen at 500 and 1000 mg/kd/day.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ Dosages of 100, 500, or 1000 mg/kg/day fed to B6C3F1 mice for 2 weeks produced slight hepatocellular hypertrophy at 500 mg/kg/day and above in males, and at 1000 mg/kg/day in females. The NOEL was 100 mg/kg/day. Dosages ranging from 50 to 1000 mg/kg/day given for 13 weeks produced slight centrilobular and midzonal hepatocellular hypertrophy at 100 mg/kg/day and above in males, and at 500 mg/kg/day and above in females. Electron microscopy characterized the hypertrophy as an increase in rough endoplasmic reticulum (RER) with a decrease in cytoplasmic glycogen content. Kidney effects in mice consisted of decreased vacuolation of the renal tubules, consistent with decreased cytoplasmic lipid, accompanied by lower kidney weights at 500 mg/kg/day and higher. The subchronic lowest observed effect level (LOEL) and NOEL values in mice were 100 and 50 mg/kg/day, respectively.

For more Non-Human Toxicity Excerpts (Complete) data for CLORANSULAM-METHYL (14 total), please visit the HSDB record page.

The aqueous hydrolysis half-life of cloransulam-methyl is reported as >365, 118 to 231 and 3 days at pH 5, 7 and 9, respectively(1). A hydrolysis half-life of 10 days in natural water at an approximate pH of 8 and 67 days in a soil slurry at an approximate pH 6.5 were also reported(1). Photolysis half-lives of cloransulam-methyl were reported as 54 minutes and 13 days for aqueous and moist soil, respectively(1).

Tolerances are established for residues of the herbicide, cloransulam-methyl, N-(2-carboxymethyl-6-chlorophenyl)-5-ethoxy-7-fluoro-(1,2,4)-triazolo[1,5c]-pyrimidine-2-sulfonamide, plus its acid, cloransulam, calculated as parent ester in or on the following raw agricultural commodities:[Table#6603]

Used as herbicide to control broadleaf weeds in soy beans; [HSDB]

Farming (Pesticides) [Category: Industry]

For cloransulam-methyl (USEPA/OPP Pesticide Code: 129116) 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./

Herbicide

... Used pre- and post-emergence for the control of broad-leaved weeds in soya beans and other crops. It is applied only on the ground.

USEPA/OPP Pesticide Code 129116; Trade Names: XDE-565.

... Formulated as a 84% water dispersable granular in water soluble packaging. ... Cloransulam-methyl Technical is a 97.5% manufacturing use product.

Premix Partners: Sulfentrazone

XR-565, PACTO (South America), SUPRA (South America)

For more Formulations/Preparations (Complete) data for CLORANSULAM-METHYL (11 total), please visit the HSDB record page.