barban

H302: Harmful if swallowed [Warning Acute toxicity, oral]

H317: May cause an allergic skin reaction [Warning Sensitization, Skin]

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

H410: Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]

P261, P264, P270, P272, P273, P280, P301+P317, P302+P352, P321, P330, P333+P317, P362+P364, P391, and P501 (click each P-code to see the statement)

H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]

H317 (100%): May cause an allergic skin reaction [Warning Sensitization, Skin]

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

H410 (100%): Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]

Aggregated GHS information provided per 42 reports by companies from 3 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

P261, P264, P270, P272, P280, P301+P317, P302+P352, P321, P330, P333+P317, P362+P364, and P501 (click each P-code to see the statement)

Excerpt from ERG Guide 171 [Substances (Low to Moderate Hazard)]:

Refer to the "General First Aid" section. (ERG, 2024)

Excerpt from ERG Guide 171 [Substances (Low to Moderate Hazard)]:

CAUTION: Fire involving Safety devices (UN3268) and Fire suppressant dispersing devices (UN3559) may have a delayed activation and a risk of hazardous projectiles. Extinguish the fire at a safe distance.

SMALL FIRE: Dry chemical, CO2, water spray or regular foam.

LARGE FIRE: Water spray, fog or regular foam. Do not scatter spilled material with high-pressure water streams. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal.

FIRE INVOLVING TANKS: Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. (ERG, 2024)

If material /is/ on fire or involved in /a/ fire do not extinguish fire unless flow can be stopped. Use water in flooding quantities as fog. Solid streams of water may be ineffective. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use "alcohol" foam, dry chemical or carbon dioxide. /Carbamate pesticide, liquid, nos, (compounds and preparations) (agricultural insecticides, nec, liquid); Carbamate pesticide, liquid, nos (compounds and preparations) (agricultural insecticides, nec, liquid); Carbamate pesticide, liquid, nos (compounds and preparations) (insecticides, other than agricultural, nec/

Do not extinguish fire unless flow can be stopped. Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Solid streams of water may be ineffective. Use foam, dry chemical, or carbon dioxide. /Carbamate pesticide, liquid nos (compounds and preparations) (insecticides, other than agricultural, nec)/

Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Use water in flooding quantities as fog. Use "alcohol" foam, dry chemical or carbon dioxide. /Carbamate pesticide, solid, nos (compounds and preparations) (insecticides, other than agricultural, nec)/

Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Use water in flooding quantities as fog. Use foam, dry chemical, or carbon dioxide. /Carbamate pesticide, solid, nos (compounds and preparations) (agricultural insecticides, nec, other than liquid)/

Excerpt from ERG Guide 171 [Substances (Low to Moderate Hazard)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

A system for removing pesticides from the wash water produced by pesticide applicators as they clean their equipment has been developed. The first step is the flocculation/coagulation and sedimentation of the pesticide-contaminated wash water. The supernatant from the first step is then passed through activated carbon columns. /Pesticides/

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure 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, aquatic, and plant life; and conformance with environmental and public health regulations.

SRP: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at end of shift, but should remain at employee's place of work for cleaning.

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.

SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

/When handling/ do not get in eyes, or on skin or clothing.

Excerpt from ERG Guide 171 [Substances (Low to Moderate Hazard)]:

Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent dust cloud. For Asbestos, avoid inhalation of dust. Cover spill with plastic sheet or tarp to minimize spreading. Do not clean up or dispose of, except under supervision of a specialist.

SMALL DRY SPILL: With clean shovel, place material into clean, dry container and cover loosely; move containers from spill area.

SMALL SPILL: Pick up with sand or other non-combustible absorbent material and place into containers for later disposal.

LARGE SPILL: Dike far ahead of liquid spill for later disposal. Cover powder spill with plastic sheet or tarp to minimize spreading. Prevent entry into waterways, sewers, basements or confined areas. (ERG, 2024)

Aluminum, phenolic-lined cans, or glass are recommended for lengthy storage

Do not store near or contaminate feed or foodstuffs. Do not ... store near heat or open flame.

A time-limited tolerance, with an expiration date of January 1, 1998, is established for negligible residues of the herbicide barban (4-chloro-2-butynyl m-chlorocarbanilate) in or on the raw agricultural commodities barley, flax, seed, lentils, mustard, seed, pea, safflower seed, soybean, sugar beet, sugar beet tops, sunflower, seed, and wheat.

Excerpt from ERG Guide 171 [Substances (Low to Moderate Hazard)]:

Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing provides thermal protection but only limited chemical protection. (ERG, 2024)

Possible allergic reaction in man by skin contact should be avoided by the use of plastic protective clothing.

Wear positive pressure self-contained breathing apparatus. ... Wear appropriate chemical protective clothing. /Carbamate pesticide, liquid, not otherwise specified (compounds and preparations) (agricultural insecticides, nec, liquid)/

Wear appropriate chemical protective gloves, boots and goggles. ... Wear positive pressure self-contained breathing apparatus when fighting fires involving this material. /Carbamate pesticide, liquid, nos (compounds and preparations) (agricultural insecticides, nec, liquid); carbamate pesticide, liquid, nos (compounds and preparations) (insecticides, other than agricultural, nec)/

Wear positive pressure self-contained breathing apparatus. ... Wear appropriate chemical protective clothing. /Carbamate pesticide, liquid, nos (compounds and preparations) (insecticides, other than agricultural, nec)/

Wear appropriate chemical protective gloves, boots and goggles. ... Wear positive pressure self-contained breathing apparatus when fighting fires involving this material. /Carbamate pesticide, solid, nos (compounds and preparations) (insecticides, other than agricultural, nec); Carbamate pesticide, solid, nos (compounds and preparations) (agricultural insecticides, nec, other than liquid)/

Barban is a crystalline solid. Water solubility is 11 ppm at 20 °C. Used as a selective herbicide.

Colorless odorless solid; [HSDB]

Crystalline solid

COLORLESS

Crystals from n-hexane + benzene

ODORLESS SOLID

Degrades before boiling

75-76 °C

122 °F (Closed cup)

At 25 °C g/100 g solvent: benzene 32.7 g; n-butylbenzene 11.3 g; n-dodecane less than 0.1 g; n-hexane 0.14 g; isopropylbenzene less than 7.0 g; kerosene 0.39 g; toluene 25.7 g; 2,2,4-trimethylpentane more than 0.3 g; xylene 27.9 g; water 0.0011 g

In water, 1.1X10+1 mg/L at 25 °C

1.403 g/cu cm at 25 °C

0.00000038 [mmHg]

3.8X10-7 mm Hg at 25 °C

log Kow = 3.41 /Estimated/

Henry's Law constant: 1.17X10-8 atm cu m/mol at 25 °C /Estimated/

Stable under normal conditions of use; hydrolysis is very rapid in alkali with displacement of the terminal chlorine substituent, DT50 58 sec (pH 13, 25 °C).

Storage at alternating temp of 50 to -15 °C for 6 months had no adverse effects on emulsion performance

When heated to decomposition it emit very toxic fumes of /hydrogen chloride and nitrogen oxides/.

Technical decomposes at 224 °C.

Liq concn may cause corrosion of tin plate & mild steel at the liq-air interface; aluminum, phenolic-lined cans or glass are recommended for storage

Corrosive

Tan solid /Technical/

Hydrolyzed by alkali with liberation of the terminal chlorine. Hydrolysis under acidic conditions gives 3-chloroacrylic acid

Decomposition temperature: not available; technical material greater than 95% pure is pale brown with faint odor.

VP = 0.05 mPa at 25 °C

For more Other Experimental Properties (Complete) data for BARBAN (7 total), please visit the HSDB record page.

Fusion temperature

Melting temperature

Phase transition

Transition enthalpy

Herbicides

Active substance -> EU Pesticides database: Not approved

Pesticides -> Herbicides, Other

Pesticide

Hydrolyzed by strong acid or base.

Carbamates

Halogenated Organic Compounds

Alkynes, with No Acetylenic Hydrogen

Aryl Halides

BARBAN is a carbamate ester. Carbamates are chemically similar to, but more reactive than amides. Like amides they form polymers such as polyurethane resins. Carbamates are incompatible with strong acids and bases, and especially incompatible with strong reducing agents such as hydrides. Flammable gaseous hydrogen is produced by the combination of active metals or nitrides with carbamates. Strongly oxidizing acids, peroxides, and hydroperoxides are incompatible with carbamates.

Barban is a cholinesterase or acetylcholinesterase (AChE) inhibitor. Carbamates form unstable complexes with chlolinesterases by carbamoylation of the active sites of the enzymes. This inhibition is reversible. A cholinesterase inhibitor suppresses the action of acetylcholine esterase. Because of its essential function, chemicals that interfere with the action of acetylcholine esterase are potent neurotoxins, causing excessive salivation and eye-watering in low doses. Headache, salivation, nausea, vomiting, abdominal pain and diarrhea are often prominent at higher levels of exposure. Acetylcholine esterase breaks down the neurotransmitter acetylcholine, which is released at nerve and muscle junctions, in order to allow the muscle or organ to relax. The result of acetylcholine esterase inhibition is that acetylcholine builds up and continues to act so that any nerve impulses are continually transmitted and muscle contractions do not stop.

Pesticide

Smith, C.D. and Nowell, L.H., 2024. Health-Based Screening Levels for evaluating water-quality data (3rd ed.). DOI:10.5066/F71C1TWP

No indication of carcinogenicity to humans (not listed by IARC).

Acute exposure to cholinesterase inhibitors can cause a cholinergic crisis characterized by severe nausea/vomiting, salivation, sweating, bradycardia, hypotension, collapse, and convulsions. Increasing muscle weakness is a possibility and may result in death if respiratory muscles are involved. Accumulation of ACh at motor nerves causes overstimulation of nicotinic expression at the neuromuscular junction. When this occurs symptoms such as muscle weakness, fatigue, muscle cramps, fasciculation, and paralysis can be seen. When there is an accumulation of ACh at autonomic ganglia this causes overstimulation of nicotinic expression in the sympathetic system. Symptoms associated with this are hypertension, and hypoglycemia. Overstimulation of nicotinic acetylcholine receptors in the central nervous system, due to accumulation of ACh, results in anxiety, headache, convulsions, ataxia, depression of respiration and circulation, tremor, general weakness, and potentially coma. When there is expression of muscarinic overstimulation due to excess acetylcholine at muscarinic acetylcholine receptors symptoms of visual disturbances, tightness in chest, wheezing due to bronchoconstriction, increased bronchial secretions, increased salivation, lacrimation, sweating, peristalsis, and urination can occur. Chronically high (>10 years) exposure leads to neuropsychological consequences including disturbances in perception and visuo-motor processing (A15321).

Inhalation (L793) ; oral (L793); dermal (L793)

As with organophosphates, the signs and symptoms are based on excessive cholinergic stimulation. Unlike organophosphate poisoning, carbamate poisonings tend to be of shorter duration because the inhibition of nervous tissue acetylcholinesterase is reversible, and carbamates are more rapidly metabolized. Muscle weakness, dizziness, sweating and slight body discomfort are commonly reported early symptoms. Headache, salivation, nausea, vomiting, abdominal pain and diarrhea are often prominent at higher levels of exposure. Contraction of the pupils with blurred vision, incoordination, muscle twitching and slurred speech have been reported. (L795)

Chemical: BARBAN

Skin Sensitizer - An agent that can induce an allergic reaction in the skin.

LC50 (rat) = 23,000 mg/m3/4hr

LD50 Rabbit oral 600 mg/kg

LD50 Mouse oral 322 mg/kg

LD50 Guinea pig oral 240 mg/kg

LD50 Rat percutaneous >1600 mg/kg

For more Non-Human Toxicity Values (Complete) data for BARBAN (6 total), please visit the HSDB record page.

If the compound has been ingested, rapid gastric lavage should be performed using 5% sodium bicarbonate. For skin contact, the skin should be washed with soap and water. If the compound has entered the eyes, they should be washed with large quantities of isotonic saline or water. In serious cases, atropine and/or pralidoxime should be administered. Anti-cholinergic drugs work to counteract the effects of excess acetylcholine and reactivate AChE. Atropine can be used as an antidote in conjunction with pralidoxime or other pyridinium oximes (such as trimedoxime or obidoxime), though the use of '-oximes' has been found to be of no benefit, or possibly harmful, in at least two meta-analyses. Atropine is a muscarinic antagonist, and thus blocks the action of acetylcholine peripherally.

Skin contamination should be treated promptly by washing with soap and water. Contamination of the eyes should be treated immediately by prolonged flushing of the eyes with large amounts of clean water. If dermal or ocular irritation persists, medical attention should be obtained without delay. /Other Herbicides/

If serious dehydration and electrolyte depletion have occurred as a result of vomiting and diarrhea, monitor blood electrolytes and and fluid balance and administer intravenous infusions of glucose, normal saline ringer's solution, or ringer's lactate to restore extracellular fluid volume and electrolytes. Follow this with oral nutrients as soon as fluids can be retained. Fluids serve to support excretion of the toxicants. Supportive measures are ordinarily sufficient for successful management of excessive exposures to these herbicides. /Other Herbicides/

/SIGNS AND SYMPTOMS/ Barban... is a potent skin sensitizing agent in man.

/LABORATORY ANIMALS: Acute Exposure/ In the case of barban ... the reported incidence of contact sensitivity due to exposure is rare; however, predictive testing with the guinea pig maximization test (GPMT) ... indicate that this pesticide is a potent sensitizer.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ Daily /oral/ administration of 0.1 LD50 to guinea pigs and rabbits for 4-6 months is said to have caused fatty dystrophy of the liver and kidneys, hemosiderosis of the spleen and vascular hyperemia of liver, brain, kidneys, spleen and gastric mucosa. Daily doses of 20-40 mg/kg to rabbits caused a significant decrease in liver glycogen content.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ Barbane is somewhat more toxic than propham with oral LD50 of 600 mg/kg for rats and rabbits and 24 mg/kg for guinea pigs.

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ No untoward behavioral or physiological reactions observed in albino rats after 21 months of chronic oral toxicity studies, or in dogs after 14 months. ...Caused transient eye irritation in albino rabbits.

For more Non-Human Toxicity Excerpts (Complete) data for BARBAN (7 total), please visit the HSDB record page.

LC50 Goldfish 1.3 ppm (96 hr) /Conditions of bioassay not specified in source examined/

LC50 Guppies 1.3 ppm (96 hr) /Conditions of bioassay not specified in source examined/

LC50 Rainbow trout 0.6 mg/L (96 hr test) /Conditions of bioassay not specified in source examined/

LC50 Bluegill 1.2 mg/L (96 hr) /Conditions of bioassay not specified in source examined/

For more Ecotoxicity Values (Complete) data for BARBAN (8 total), please visit the HSDB record page.

/FIELD STUDIES/ At the application level of 5 kg/ha (20 ppm) on the soil Psuedogley-Parabraunerde cretaceous clay, barban killed 40 percent of ammonium oxidizers, based upon the assumption of initial inhibition(1). The estimated rate of application of barban for > 25 percent inhibition in soil (ammonium oxidation) was 100 to 250 kg/ha at 0.5 to 2 applications per year. The estimated rate of application of barban for > 25 percent inhibition in soil (nitrite oxidation) was 1 to 2 kg/ha at 0.5 to 2 applications per year(2).

Barban's former production and use as a herbicide and plant growth regulator is expected to have resulted in its direct release to the environment. If released to air, a vapor pressure of 3.8X10-7 mm Hg at 25 °C indicates barban will exist in both the vapor and particulate phases the ambient atmosphere. Vapor-phase barban 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 7 hrs. Particulate-phase barban will be removed from the atmosphere by wet and dry deposition. Barban does not contain chromophores that would be expected to absorb light at wavelengths >290 nm and would not be expected to be susceptible to direct photolysis by sunlight. If released to soil, barban is expected to have low mobility based upon an estimated Koc of 1,200. Barban was found to disappear more rapidly in non-autoclaved soil than in autoclaved soil and appeared to be stable in the presence of anaerobic microorganisms, however specific details were not available. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 1.2X10-8 atm-cu m/mole. Barban is not expected to volatilize from dry soil surfaces based upon its vapor pressure. If released into water, barban is 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 Henry's Law constant. An estimated BCF of 160 suggests the potential for bioconcentration in aquatic organisms is moderate. Hydrolysis may be an important environmental fate process as indicated by estimated half-lives of 1.1 hours and 6.84 minutes at pH values of 7 and 8, respectively. Occupational exposure and general population exposure should be low or non-existent since barban is no longer produced or used in the US (May, 2005). In the past, barban was applied directly to the barley and wheat crops as a herbicide and occupational exposure to this compound was primarily by inhalation of dust particles and dermal contact. (SRC)

Barban's former production and use as a herbicide and plant growth regulator(1) is expected to have resulted in its direct release to the environment(SRC).

Decomposes within 28-38 days of the last plant spraying.

TERRESTRIAL FATE: RESULTANT AVG PERSISTENCE @ RECOMMENDED RATES: DOWN TO TRACE AMT WITHIN 3 WK IN MOST SOILS.

Terrestrial fate: Duration of residual activity in soil 2-3 months (at 3 kg/ha).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1,200(SRC), determined from a water solubility of 11 mg/L(2) and a regression-derived equation(3), indicates that barban is expected to have low mobility in soil(SRC). Volatilization of barban from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.2X10-8 atm-cu m/mole(SRC), derived from its vapor pressure, 3.8X10-7 mm Hg(4), and water solubility mg/L(2). Barban is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). Barban was found to disappear more rapidly in non-autoclaved soil than in autoclaved soil(5) and appeared to be stable in the presence of anaerobic microorganisms(6); however, specific details were not available.

For more Environmental Fate (Complete) data for BARBAN (7 total), please visit the HSDB record page.

AEROBIC: Barban was found to disappear more rapidly in non-autoclaved soil than in autoclaved soil(1). Barban was degraded to 3-chloroaniline by a soil isolate of Penicillium sp. The barban-hydrolyzing enzyme was presumed to be an amidase(2). It was determined that the alkaline hydrolysis of barban leads to the degradation product 3-chloroaniline(3).

ANAEROBIC: Barban appeared to be stable in the presence of anaerobic microorganisms(1).

The rate constant for the vapor-phase reaction of barban with photochemically-produced hydroxyl radicals has been estimated as 5.5X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 7 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the vapor-phase reaction of barban with ozone has been estimated as 2.7X10-20 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(1). This corresponds to an atmospheric half-life of about 420 days at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(2). A base-catalyzed second-order hydrolysis rate constant of 1.63X103 L/mole-sec(SRC) was estimated using a structure estimation method(3); this corresponds to half-lives of 1.1 hours and 6.84 minutes at pH values of 7 and 8, respectively(3). Barban does not contain chromophores that would be expected to absorb light at wavelengths >290 nm and would therefore not be susceptible to direct photolysis by sunlight(SRC).

LC50 Goldfish 1.3 ppm (96 hr) /Conditions of bioassay not specified in source examined/

LC50 Guppies 1.3 ppm (96 hr) /Conditions of bioassay not specified in source examined/

LC50 Rainbow trout 0.6 mg/L (96 hr test) /Conditions of bioassay not specified in source examined/

LC50 Bluegill 1.2 mg/L (96 hr) /Conditions of bioassay not specified in source examined/

For more Ecotoxicity Values (Complete) data for BARBAN (8 total), please visit the HSDB record page.

/FIELD STUDIES/ At the application level of 5 kg/ha (20 ppm) on the soil Psuedogley-Parabraunerde cretaceous clay, barban killed 40 percent of ammonium oxidizers, based upon the assumption of initial inhibition(1). The estimated rate of application of barban for > 25 percent inhibition in soil (ammonium oxidation) was 100 to 250 kg/ha at 0.5 to 2 applications per year. The estimated rate of application of barban for > 25 percent inhibition in soil (nitrite oxidation) was 1 to 2 kg/ha at 0.5 to 2 applications per year(2).

Barban's former production and use as a herbicide and plant growth regulator is expected to have resulted in its direct release to the environment. If released to air, a vapor pressure of 3.8X10-7 mm Hg at 25 °C indicates barban will exist in both the vapor and particulate phases the ambient atmosphere. Vapor-phase barban 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 7 hrs. Particulate-phase barban will be removed from the atmosphere by wet and dry deposition. Barban does not contain chromophores that would be expected to absorb light at wavelengths >290 nm and would not be expected to be susceptible to direct photolysis by sunlight. If released to soil, barban is expected to have low mobility based upon an estimated Koc of 1,200. Barban was found to disappear more rapidly in non-autoclaved soil than in autoclaved soil and appeared to be stable in the presence of anaerobic microorganisms, however specific details were not available. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 1.2X10-8 atm-cu m/mole. Barban is not expected to volatilize from dry soil surfaces based upon its vapor pressure. If released into water, barban is 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 Henry's Law constant. An estimated BCF of 160 suggests the potential for bioconcentration in aquatic organisms is moderate. Hydrolysis may be an important environmental fate process as indicated by estimated half-lives of 1.1 hours and 6.84 minutes at pH values of 7 and 8, respectively. Occupational exposure and general population exposure should be low or non-existent since barban is no longer produced or used in the US (May, 2005). In the past, barban was applied directly to the barley and wheat crops as a herbicide and occupational exposure to this compound was primarily by inhalation of dust particles and dermal contact. (SRC)

Barban's former production and use as a herbicide and plant growth regulator(1) is expected to have resulted in its direct release to the environment(SRC).

Decomposes within 28-38 days of the last plant spraying.

TERRESTRIAL FATE: RESULTANT AVG PERSISTENCE @ RECOMMENDED RATES: DOWN TO TRACE AMT WITHIN 3 WK IN MOST SOILS.

Terrestrial fate: Duration of residual activity in soil 2-3 months (at 3 kg/ha).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1,200(SRC), determined from a water solubility of 11 mg/L(2) and a regression-derived equation(3), indicates that barban is expected to have low mobility in soil(SRC). Volatilization of barban from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.2X10-8 atm-cu m/mole(SRC), derived from its vapor pressure, 3.8X10-7 mm Hg(4), and water solubility mg/L(2). Barban is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). Barban was found to disappear more rapidly in non-autoclaved soil than in autoclaved soil(5) and appeared to be stable in the presence of anaerobic microorganisms(6); however, specific details were not available.

For more Environmental Fate (Complete) data for BARBAN (7 total), please visit the HSDB record page.

AEROBIC: Barban was found to disappear more rapidly in non-autoclaved soil than in autoclaved soil(1). Barban was degraded to 3-chloroaniline by a soil isolate of Penicillium sp. The barban-hydrolyzing enzyme was presumed to be an amidase(2). It was determined that the alkaline hydrolysis of barban leads to the degradation product 3-chloroaniline(3).

ANAEROBIC: Barban appeared to be stable in the presence of anaerobic microorganisms(1).

The rate constant for the vapor-phase reaction of barban with photochemically-produced hydroxyl radicals has been estimated as 5.5X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 7 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the vapor-phase reaction of barban with ozone has been estimated as 2.7X10-20 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(1). This corresponds to an atmospheric half-life of about 420 days at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(2). A base-catalyzed second-order hydrolysis rate constant of 1.63X103 L/mole-sec(SRC) was estimated using a structure estimation method(3); this corresponds to half-lives of 1.1 hours and 6.84 minutes at pH values of 7 and 8, respectively(3). Barban does not contain chromophores that would be expected to absorb light at wavelengths >290 nm and would therefore not be susceptible to direct photolysis by sunlight(SRC).

10 ppm barban in water was irradiated for 135 minutes with sunlight lamps at a wavelength of 300 nm in the presence of the surfactants Tergitol TMN-10 (0.2 percent) and Trition X-100 (0.2 percent). Percent loss of barban in pure water was 22; percent loss of barban in the presence of Tergitol TMN-10 and Trition X-100 was 76 and 99 percent, respectively(1). The absorption of barban in n-hexane and ethanol occurred between 277 and 286 nm(2).

2-Chloro-4-aminophenol has been identified as a metabolite of barban in plants(1). It was demonstrated that barban was metabolized in both tolerant wheat and sensitive wild oat to 3-chloroaniline. In leaf-treated tissues, it was concluded that 14C-labeled barban concentration decreased with time and the 3-chloroaniline moiety of barban was complexed as polar metabolites. It was also determined that root-treated soybean plants absorb, translocate, and metabolize 14C-labeled barban. These studies indicated that the barban molecule was not cleaved in soybean(2).

An estimated BCF of 160 was calculated for barban(SRC), using water solubility of 11 mg/L,(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is high (SRC), provided the compound is not metabolized by the organism(SRP).

The Koc of barban is estimated as 1,200(SRC), derived from its water solubility of 11 mg/L(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that barban is expected to have slight mobility in soil. Using TLC and aluminum oxide sorbent, the Rf value of barban was determined to be 0.5(4). The phenylcarbamate herbicides are much more water soluble than the substituted anilines(5). In spite of this, however, they are very immobile in soil systems. These compounds have been shown to be activated by adsorption to soil organic matter. Compounds in this group include barban. The mechanism of adsorption to soil organic matter is thought to involve hydrogen bonding between the carboxyl groups of the organic matter and the nitrogen and carbonyl oxygen of the carbamate(5).

The Henry's Law constant for barban is estimated as 1.2X10-8 atm-cu m/mole(SRC) derived from its vapor pressure, 3.8X10-7 mm Hg(1), and water solubility, 11 mg/L(2). This Henry's Law constant indicates that barban is expected to be essentially nonvolatile from water surfaces(3). Barban is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

GROUNDWATER: Groundwater sampling for pesticides in the United States was conducted by the EPA from 1971 to 1991. Results showed that out of 140 wells sampled in California from 1987 to 1989, no concentration of barban was detected; out of 120 wells sampled in California from 1989 to 1989, no concentration of barban was detected(1). A five year survey of water samples from 738 rural domestic wells and 566 community wells was conducted nationwide. The National Pesticide Survey reporting limit for barban was 1.9 ug/l; barban was not detected in the wells(2). Sampling for pesticides was conducted on 3,322 wells in 47 counties of California from 1993 to 1995. Results showed that out of 35 wells sampled in 3 counties, no concentration of barban was detected(3).

Occupational exposure and general population exposure should be low or non-existent since barban is no longer produced or used. In the past, barban was applied directly to the barley and wheat crops as a herbicide and exposure to this compound was primarily by inhalation of dust particles and dermal contact. (SRC)

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure 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, aquatic, and plant life; and conformance with environmental and public health regulations.

IMO 6.1; Carbamate pesticides, solid, toxic, nos; carbamate pesticides, liquid, toxic, flammable, nos, flashpoint between 23 °C and 61 °C; carbamate pesticides, liquid, toxic, nos; carbamate pesticides, liquid, NOS

IMO 3.2; Carbamate pesticides, liquid, flammable, toxic, nos, flashpoint less than 23 °C

UN 2757; Carbamate pesticides, solid, toxic, nos; carbamate pesticides, liquid, nos

UN 2758; Carbamate pesticides, liquid, flammable, toxic, nos, flashpoint less than 23 °C

For more Shipping Name/ Number DOT/UN/NA/IMO (Complete) data for BARBAN (6 total), please visit the HSDB record page.