2,6-Dichlorobenzonitrile

172.01

172.01

1909167

214-787-5

N42NR4196R

0867

521490

3082|2769

DTXSID5032365

White crystalline solid

29269090

23.8

2.64

Dichlobenil is a white solid dissolved or suspended in a water-emulsifiable liquid carrier. The primary hazard is the threat to the environment. Immediate steps should be taken to limit spread to the environment. Can easily penetrate the soil and contaminate groundwater and nearby streams. Can cause illness by inhalation, skin absorption and/or ingestion. Used as a herbicide.

1.3 g/cm³

144-145 °C

270 °C

270°C

1.6000 (estimate)

H2O: 25 mg/L (25 ºC)

0-6°C

Vapour pressure, Pa at 20°C: 0.073

LD50 in rats, mice (mg/kg): 2710, 6800 orally (Bailey, White)

Aromatic odor

Henry's Law constant= 1.0X10-5 atm-cu m/mole at 25 °C (est)

Hydroxyl radical reaction rate constant = 1.7X10-13 cu cm/molec-sec at 25 °C (est)

Not soluble in water.

Nitriles

A halogenated nitrile. Nitriles may polymerize in the presence of metals and some metal compounds. They are incompatible with acids; mixing nitriles with strong oxidizing acids can lead to extremely violent reactions. Nitriles are generally incompatible with other oxidizing agents such as peroxides and epoxides. The combination of bases and nitriles can produce hydrogen cyanide. Nitriles are hydrolyzed in both aqueous acid and base to give carboxylic acids (or salts of carboxylic acids). These reactions generate heat. Peroxides convert nitriles to amides. Nitriles can react vigorously with reducing agents. Acetonitrile and propionitrile are soluble in water, but nitriles higher than propionitrile have low aqueous solubility. They are also insoluble in aqueous acids.

Not Applicable. Not flammable. (USCG, 1999)

NON-CORROSIVE

III

9

UN 3077 9/PG 3

2

21-51/53

36/37-61

DI3500000

Xn,N,T,Xi

Provision to contain effluent from fire extinguishing. Separated from oxidants and food and feedstuffs. Store in an area without drain or sewer access.

Irritant/Toxic

Stable to heat, <270 deg C. Stable to acids, but rapidly hydrolysed by strong alkalis to 2,6-dichlorobenzamide. In sterile aqueous solutions at pH 5, 7 and 9 in the dark (22 deg C), decomposition only 5-10% after 150 days.

P273-P280

H312-H411

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.|Safe Disposal of Pesticides. The best way to dispose of small amounts of excess pesticides is to use them - apply them - according to the directions on the label. If you cannot use them, ask your neighbors whether they have a similar pest control problem and can use them. If all of the remaining pesticide cannot be properly used, check with your local solid waste management authority, environmental agency, or health department to find out whether your community has a household hazardous waste collection program or a similar program for getting rid of unwanted, leftover pesticides. These authorities can also inform you of any local requirements for pesticide waste disposal.|Safe Disposal of Pesticides. An empty pesticide container can be as hazardous as a full one because of residues left inside. Never reuse such a container. When empty, a pesticide container should be rinsed carefully three times and the rinsewater thoroughly drained back onto the sprayer or the container previously used to mix the pesticide. Use the rinsewater as a pesticide, following label directions. Replace the cap or closure securely. Dispose of the container according to label instructions. Do not puncture or burn a pressurized container like an aerosol - it could explode. Do cut or puncture other empty pesticide containers made of metal or plastic to prevent someone from reusing them. Wrap the empty container and put it in the trash after you have rinsed it.

Dichlobenil as a suspension in water does not deteriorate. It is compatible with most wettable powder herbicides. Mixing with water soluble fertilizers or emulsifiable herbicides is not recommended.

FOLMAR EC; US FISH WILDL SERV TECH PAP (88): 1-16 (1977). REVIEW: TOXICITY TABLES FOR HERBICIDES INCL DICHLOBENIL LIST TEST ORGANISMS, TYPES OF TESTS, EXPTL CONDITIONS AND TEST RESULTS. EACH TABLE IS FOLLOWED BY A LIST OF REFERENCES.|Hill EF, Camardese MB; US Fish Wildl Serv Fish Wildl Tech Rep 2: 1-147 (1986). The report provides the most comprehensive data base available for avian subacute dietary toxicity tests and is primarily intended for use in ranking toxicities by a standard method that has a reasonable degree of environmental relevance.|Rice TR JR, Duke TW JR; US Fish Wildlife Serv Circ 335: 1-33 (1970). The effects of dichlobenil on the biota and energy budget of a coastal pond ecosystem.|USEPA/Office of Pesticide Programs; Reregistration Eligibility Decision Document - Dichlobenil. EPA-738-R-98-003 October 1998. The RED summarizes the risk assessment conclusions and outlines any risk reduction measures necessary for the pesticide to continue to be registered in the U.S.[Available from, as of February 7, 2006: http://www.epa.gov/pesticides/reregistration/status.htm]

Not flammable. (USCG, 1999)|Not combustible. Gives off irritating or toxic fumes (or gases) in a fire.

|Warning|H312: Harmful in contact with skin [Warning Acute toxicity, dermal]|P273, P280, P302+P352, P312, P322, P363, P391, and P501|H312 (98.55%): Harmful in contact with skin [Warning Acute toxicity, dermal]|Aggregated GHS information provided by 69 companies from 4 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.|H303: May be harmful if swallowed [Warning Acute toxicity, oral]|P260, P312, P314, and P501

Excerpt from ERG Guide 171 [Substances (Low to Moderate Hazard)]: As an 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, in the downwind direction, as necessary, the isolation distance shown above. FIRE: If tank, rail car or tank truck 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, 2016)

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. Avoid inhalation of asbestos dust. 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, 2016)

Wear goggles, self-contained breathing apparatus, protective clothing, and rubber gloves. (USCG, 1999)|Personnel portection: ... Wear appropriate chemical protective gloves, boots and goggles.

The formulated product is nonflammable.

If material involved in fire: Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.)

Not combustible. Gives off irritating or toxic fumes (or gases) in a fire.

Spills of pesticides at any stage of their storage or handling should be treated with great care. Liquid formulations may be reduced to solid phase by evaporation. Dry sweeping of solids is always hazardous: These should be removed by vacuum cleaning or by dissolving them in water or other solvent in the factory environment. /Pesticides/|Environmental considerations: Land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. /SRP: Pits, ponds, lagoons, soak holes or holding areas used to contain the chemical should be sealed with a impermeable flexible membrane liner./ Cover solids with a plastic sheet to prevent dissolving in rain or fire fighting water.|Environmental considerations: Water spill: If dissolved, in region of 10 ppm or greater concentration, apply activated carbon at ten times the spilled amount.|Personal protection: P2 filter respirator for harmful particles. Do NOT let this chemical enter the environment. Sweep spilled substance into sealable containers; if appropriate, moisten first to prevent dusting. Carefully collect remainder, then remove to safe place.|For more Cleanup Methods (Complete) data for DICHLOBENIL (6 total), please visit the HSDB record page.

Do not breath dust. Do not allow contact with eyes or skin.|Smoking, eating, drinking /and the use of toilet facilities/ before washing should be absolutely prohibited when any pesticide of moderate or higher toxicity is being handled or used. /Pesticides/|Use with caution. Avoid contamination of feed and feed stuffs. Do not apply during periods of high soil temp without immediate incorporation. On sandy soils lower dosages should be applied.|Prevention /from dichlobenil/ inhalation /use/ ventilation (not if powder), local exhaust, or breathing protection.|For more Preventive Measures (Complete) data for DICHLOBENIL (9 total), please visit the HSDB record page.

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Do NOT let this chemical enter the environment. Sweep spilled substance into covered sealable containers. If appropriate, moisten first to prevent dusting. Carefully collect remainder. Then store and dispose of according to local regulations.

Provision to contain effluent from fire extinguishing. Separated from oxidants and food and feedstuffs. Store in an area without drain or sewer access.

A harmful concentration of airborne particles can be reached quickly when dispersed.

The substance may have effects on the skin. This may result in chloracne.

See EFFECTS OF LONG-TERM OR REPEATED EXPOSURE.

Use ventilation (not if powder), local exhaust or breathing protection.

Protective gloves.

Wear safety goggles.

The major hazards encountered in the use and handling of dichlobenil stem from its toxicologic properties as a pesticide. Dermal effects appear to be the most common: ranging from possible contact burns to the skin and eyes, to dermatitis, including chloracne. However, dichlobenil also may be fatal if sufficiently high doses are inhaled, swallowed, or absorbed through the skin. Breathing of dichlobenil's aromatic, off-white, crystaline dust, and its contact with skin or eyes should be avoided. Where avoidance is not possible, wear boots and protective clothing, gloves, and goggles (also, a positive pressure breathing apparatus in emergency situations). Remove and isolate contaminated clothing at the exposure site and wash exposed skin well with soap and water, particularly before smoking, eating or using toilet facilities. Formulated dichlobenil is nonflammable. However, when heated to decomposition, it may evolve highly toxic fumes including phosgene or cyanide. If dichlobenil is involved in a fire, extinguish the fire using an agent suitable for the type of surrounding material. Fire-control water should be diked, as necessary to prevent dichlobenil from entering water sources and sewers. While dichlobenil is non-corrosive and thermally stable, it nevertheless should be stored in a cool, dry place, in tightly closed containers, and away from alkalis, feed and feedstuffs. Containers of dichlobenil may be shipped via air, water, road, or rail. Small spills of dichlobenil should be carefully shovelled into a clean dry container (liquid dichlobenil is first absorbed by a non-combustible material, like sand) for later disposal. Large land spills should be deposited in excavated pits, ponds, or holding areas that have been sealed with an impermeable flexible membrane liner (solids also should be covered with plastic sheeting). Spills of dichlobenil in bodies of water, first may need to be treated with activated carbon ... Before permanent land disposal of dichlobenil, consult with environmental regulatory agencies.

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 100 lb or 45.4 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b).

SOIL: Dichlobenil was detected in soil of an agricultural field in Ireland at 4.55 mg/kg (2.54 cm depth) and 0.45 mg/kg (7.62-10.16 cm depth)(1).

URBAN/SUBURBAN: Dichlobenil was detected in atmospheric samples from Vallombrosa, Italy at 3.11 mg/cu m in 1989(1).

Twenty-four hours following injection of a single dose of the herbicide dichlobenil (2,6-dichlorobenzonitrile) in C57Bl/6 mice a steep dose-response curve for the histopathological toxicity in the olfactory mucosa was observed. Four hours following injection of a toxic dose of [ring-14C]dichlobenil (12 mg/kg) the covalent binding in the olfactory mucosa was 26 times higher than that in the liver. A dose-dependent decrease of nonprotein sulfhydryls (mainly glutathione, GSH) in the olfactory mucosa was observed 2.5 hr following injection of dichlobenil (6, 12, 25 mg/kg). The synthetic GSH precursor N-acetyl-L-cysteine decreased both the dichlobenil-induced toxicity and the covalent binding, whereas N-acetyl-D-cysteine had no effect. No protective effects of the cyanide antidotes nitrite, thiosulfate, or superoxide dismutase on the dichlobenil-induced toxicity were observed. In mice given the GSH-depleting agent phorone and a subtoxic dose of dichlobenil (6 mg/kg), an extensive toxicity and an increased covalent binding in the olfactory mucosa were demonstrated. Autoradiography showed no change in the distribution of covalent (14)C dichlobenil binding to nontarget tissues of phorone-treated mice. In conclusion, the results demonstrate a relationship between the degrees of covalent binding, GSH depletion, and toxicity of dichlobenil in the olfactory mucosa. Hence, the level of GSH appears to be of importance for the dichlobenil-induced toxicity in the olfactory mucosa.|Treatment with 3-aminobenzamide decreased the toxicity and covalent binding of dichlobenil (2,6-dichlorobenzonitrile; 12 mg/kg; i.p.) in the mouse olfactory mucosa.

LD50 Mouse oral male 2126 mg/kg (14 day observation period) female 2056 mg/kg (14 day observation period)|LD50 Rat oral male 3160 mg/kg (14 day observation period), female 3160 mg/kg (14 day observation period)|LD50 Guinea pig oral male 501 mg/kg (14 day observation period), female 501 mg/kg (14 day observation period)|LD50 Mouse intraperitoneal female 603 mg/kg (14 day observation period)|For more Non-Human Toxicity Values (Complete) data for DICHLOBENIL (12 total), please visit the HSDB record page.

/BIRDS and MAMMALS/ Dichlobenil was tested in a 5 day diet of young 14 day old Japanese Quail and a 10 day old ring-necked pheasant. There was no mortality at 1250 ppm, 12% at 2500 ppm, and 19% at 5000 ppm in the quail. LC50 in pheasant was approx 1500.|/AQUATIC SPECIES/ Only 0.31-1.28 mg dichlobenil/L caused hypertrophy and hyperplasia of gill epithelial cells in rainbow trout and the accumulation of dichlobenil in the tissues was concentration related.|/AQUATIC SPECIES/ Goldfish were treated for 3 months with dichlobenil. Body wt was decrease & the behavior of the animals was abnormal only at the highest concentration (6.4 mg/L) tested. The no toxic effect level for goldfish and continuous exposure during 3 months may be given as between 0.4 and 1.6 mg/L in water. The corresponding no toxic effect residue in the whole fish is between 8 and 29 ppm.|/AQUATIC SPECIES/ ... Catfish, exposed to a 20 ppm dose of dichlobenil displayed a reduction in G alpha q/G alpha 11 antigenicity.|For more Ecotoxicity Excerpts (Complete) data for DICHLOBENIL (8 total), please visit the HSDB record page.

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

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values of 49-323 measured in several soils(2), indicates that dichlobenil is expected to have high to moderate mobility in soil(SRC). Volatilization of dichlobenil from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.0X10-5 atm-cu m/mole(SRC), derived from its vapor pressure, 6.6X10-4 mm Hg(3), and water solubility, 14.6 mg/L(3). Dichlobenil is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(3). The half-life of dichlobenil in soil is typically 1-6 months depending upon soil type, with 2,6-dichlorobenzamide (which is slowly degraded to 2,6-dichlorobenzoic acid) observed as a major metabolite(3). Field studies using a sandy soil plot and application rates of 8.3 and 16.6 kg/ha indicate that the overall persistence time of dichlobenil is approximately one year(4). An initial half-life of approximately 4 weeks was observed for surface applied dichlobenil, which was primarily due to volatilization losses. Incorporation of the granules into the soil by mechanical tillage, resulted in significantly longer persistence due to a decreased rate of volatilization(4).|TERRESTRIAL FIELD DISSIPATION: Dichlobenil dissipated with a calculated half-life of 241 days from the upper 3 inches of silt loam soil in field plots that were planted to arborvitae in Hillsboro, Oregon. The average dichlobenil concentrations from the deeper soil layers were <0.024 ppm at all sampling intervals except for 0.084 ppm in the 48 inch to 58 inch depth. There were dichlobenil detections at 36-48, 48-50, and 50-60 inches. The degradate, 2,6- dichlorobenzamide, was detected to a depth of 96 inches(1). Dichlobenil degraded from sandy loam soil with a calculated half-life of 13 weeks; most of the dissipation was due to volatilization of dichlobenil(1). Of the 61.0% of total 14C trapped, 56.8% was 14C-dichlobenil and 2.3% was 14CO2. When correcting for the volatilization, the calculated half-life of dichlobenil was 46.3 weeks. One degradate identified, 2,6-dichlorobenzamide, was 13.1% (maximum concentration) at 50 weeks(1). Dichlobenil dissipated with a calculated half-life of 3.7 months from the upper 3 inches of a loamy sand soil in an established commercial apple orchard located in the Town of Huron, New York; the orchard was treated with dichlobenil (Norosac, 4% G) at 6 lb ai/A on May 18, 1987(1). Dichlobenil was detected to a 12-inch depth in the treated plots. The degradate 2,6-dichlorobenzamide was detected to a depth of 72 inches(1). Dichlobenil dissipated with a calculated half-life of 16 days from the upper 3 inches of Hanford sandy loam soil located in Madera, California(1). A loss of 80% of the applied dichlobenil was not accounted for after a 7-day period and was attributed to volatilization. Dichlobenil was detected at a 6-inch soil depth in the treated plots. The degradate 2,6-dichlorobenzamide was consistently detected to a 48-inch soil depth.|IN SOIL, HALF-LIFE ... WAS 28 WK @ 6.7 °C (AFTER INITIAL 10 WK LAG PERIOD) & 19 WK @ 26.7 °C. ... THE ONLY DETECTABLE METABOLITE WAS 2,6-DICHLOROBENZAMIDE.|KALE PLANTS WERE EXPOSED TO DICHLOBENIL SOLN THROUGH ... SOIL TREATMENT. ... HALF-LIFE OF DICHLOBENIL @ 2.5 MG/POT WAS 44 DAYS; @ 0.5 MG/POT WAS 46 DAYS; & @ 0.25 MG/POT WAS 46 DAYS.|For more Environmental Fate (Complete) data for DICHLOBENIL (7 total), please visit the HSDB record page.

The rate constant for the vapor-phase reaction of dichlobenil with photochemically-produced hydroxyl radicals has been estimated as 1.7X10-13 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 94 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Dichlobenil exhibits an absorption maximum at 298 nm (epsilon = 2,100) in methanol(2). After irradiation at an unspecified wave length for 8 hours, the major photolytic product was o-chlorobenzonitrile. A small amount of benzonitrile was also formed(2). Irradation of dichlobenil on silica gel for 17 hr with light of >290 nm resulted in less than 0.5% loss(3). The photolysis half-life for dichlobenil in water with natural sunlight (40 deg northern latitude) has been reported as 10.2 days(4). Uniformly ring-labeled 14C-dichlobenil (radiochemical purity 99.3%) at 5.749 mg/L, degraded with a calculated half-life of 15.1 days at pH 7 under simulated sunlight conditions(5). A major degradate was 4-chloro-2-benzoxazolone, present at 17% of total radioactivity at 21 days(5). Additional degradates, found at low levels, identified in the irradiated samples at 21 days were 2-hydroxybenzonitrile (4% of total the radioactivity), 2,6-dichlorobenzoic acid (3% of the total radioactivity), 2-chlorobenzonitrile (2% of the total radioactivity), 2,6-dichlorobenzamide (1% of the total radioactivity), and 4-hydroxy-2,6-dichlorobenzonitrile (of the total radioactivity)(5). Dichlobenil is stable to degradation by hydrolysis under environmental conditions(5). The calculated half-life, extrapolated from a 30 day study, is >150 days in sterilized buffers at pH 5, 7 and 9(5).

The bioconcentration factor of dichlobenil in fish is 15-20(1). BCF values for dichlobenil ranged from 9.95 for bass to 18.5 for bluegill(2). Dichlobenil accumulated in edible (fillet) and nonedible (viscera) tissues of rainbow trout, largemouth bass, and brown bullhead catfish that were exposed to dichlobenil applied at 15 lb ai/A to a pond in Oregon. Maximum bioconcentration factors for edible, nonedible, and whole fish tissues were 12, 35, and 27 for rainbow trout; 10, 17, and 15 for largemouth bass; and 14, 21, and 17, respectively, for brown bullhead catfish(3). According to a classification scheme(4), these BCF values suggest bioconcentration in aquatic organisms is low to moderate(SRC).

316.23 L/kg|An average Koc value of 167 was reported for dichlobenil in soils(1). Soil column studies with sandy loam and loam showed that leaching was considerably less in loam, but did occur in sandy loam depending upon the irrigation rate(2). With loam and moderate irrigation most of the dichlobenil remained in the top 10 cm, while its metabolite, dichlorobenzamide, was more readily leached(2). Koc values of 49, 110, 114, 205 and 106, were measured in a silt loam (0.6% organic matter), silty loam (1.9% organic matter), aquatic sediment (2.8% organic matter), loam (3.0% organic matter) and sand (4.8% organic matter), respectively(3). Additional Koc values of 195, 323, 272, 133 and 262 were measured for dichlobenil in a sandy soil (0.28% organic matter), hydrosoil (2.24% organic matter), silt loam (4.7% organic matter), clay soil (12.4% organic matter), and sandy loam (6.9% organic matter), respectively. According to a classification scheme(4), these Koc values suggests that dichlobenil is expected to have high to moderate mobility in soil(SRC).

The Henry's Law constant for dichlobenil is estimated as 1.0X10-5 atm-cu m/mole(SRC) derived from its vapor pressure, 6.6X10-4 mm Hg(1), and water solubility, 14.6 mg/L(1). This Henry's Law constant indicates that dichlobenil is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 3 days(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 40 days(SRC). Dichlobenil's estimated Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). Dichlobenil is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1). Four weeks post application of dichlobenil to a sterile water/sediment slurry, only 25% of the initial amount of the compound remained, with the assumption that most had volatilized(3). Dichlobenil applied to soils at different moisture levels volatilized 10% at 30 °C and 18% at 40 °C in moist soils within 3 hours. Volatility increased with increasing soil moisture and volatility losses were less than 4% in air dried soils(4).

SURFACE WATER: Dichlobenil was detected at 4 monitoring sites in the Shinano River, Japan at levels of 6-32 ng/L (site 1), 10-18 ng/L (site 2), 4-54 ng/L (site 3), and 12-76 ng/L (site 4) from April-August 1996(1). Dichlobenil was identified, not quantified, in surface water in the Netherlands(2). Dichlobenil was detected in 1.4% of the samples collected in 8 urban streams in the US at a max concn of 0.3 ug/L(3). Dichlobenil was detected in 4% of the surface water samples collected from the Arno River, Italy in 1995 at a max concn of 0.05 ug/L(4). Dichlobenil was detected in stream water near an agricultural area of Ireland at 0-12.5 ug/L and in pools of an agricultural field at 23 ug/L(5). Dichlobenil was detected in two water samples from the Adige River, Italy at levels of 0.17 and 0.29 parts per trillion(6). Dichlobenil was detected in the Scheldt River, Netherlands (June 6, 1996) at a concn of 48 ng/L(7).|GROUNDWATER: Dichlobenil was detected in groundwater samples from the Netherlands at a max concn of 0.83 ug/L(1). Dichlobenil was detected in 7 out of 2,317 groundwater samples collected in the US (1992-1996) at a max concn of 0.21 ug/L(2).|DRINKING WATER: Dichlobenil was detected in well water and tap water in agricultural areas of Ireland where it had been used as an herbicide(1). The concn in farmhouse tap water was 16 ug/L and in well water was 20 ug/L(1).|RAIN/SNOW: Dichlobenil was detected in rainfall in the Netherlands at levels of 0.1-0.2 ug/L(1). Dichlobenil was detected in rainfall in Vallombrosa and Renon, Italy at levels of 0.1-3.2 ug/L from April-October 1988(2).

Dichlobenil has frequently been identified as a pesticide detected in food items under the FDA Pesticide Residue Monitoring Program. Dichlobenil was identified, not quantified, in an undisclosed number of food items under the Pesticide Residue Monitoring Program each year from 1993-1994, and 2000-2003(1). No detections were reported for food items from the 1995-1999 surveys(1). Dichlobenil was identified, not quantified, in a single orange sample during an analysis of the Pesticide Residue Monitoring Program from 1989-1991(2).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 200 workers (none of these are female) are potentially exposed to dichlobenil in the US(1). Occupational exposure to dichlobenil may occur through inhalation of dusts or dermal contact with this compound at workplaces where it is produced or used as an herbicide(SRC). Dichlobenil has frequently been detected in unspecified food items under the FDA Pesticide Residue Monitoring Program(2); therefore, the general population may be exposed to dichlobenil through the ingestion of food items containing residues of this compound(SRC).

Pesticides used to destroy unwanted vegetation, especially various types of weeds, grasses (POACEAE), and woody plants. Some plants develop HERBICIDE RESISTANCE. (See all compounds classified as Herbicides.)

Dogs (Beagles) & rats (Porter strain) did not show species differences in patterns of elimination of metabolites ... Single labeled doses ... were almost entirely eliminated in 4 days. Less than 0.5% ... was present in carcass & viscera after removal of gut ... upwards of 60% appeared in urine.|Roots and cut stems readily absorb dichlobenil from aqueous or nutrient solutions... . Dichlobenil is often absorbed and accumulated in root tissues... before it is translocated upward. ...Under favorable concentration gradients, root-absorbed dichlobenil was excreted back into nutrient solution.|...Radiocarbon from (14)carbon dichlobenil accumulates in parenchyma cells surrounding main veins of bean seedling leaves. Movement and accumulation of radiocarbon in these cells may be result of... transport via intercellular space or across the plasma lemma, adsorption to chloroplasts or other cellular components, and immobilization of conjugated phenolic metabolites as bound "terminal" residues ... (14)carbon balance and vapor-trapping studies have established that substantial amount of translocated radiocarbon is rapidly lost as... dichlobenil by evaporation from aerial portions of intact plants. ...It is also absorbed and translocated by aerial portions of plant. Absorption has been reported... from vapor... and from lanolin paste ... It was translocated in acropetal direction with very limited basipetal movement... .|Studies with (14)carbon dichlobenil showed that more of it was absorbed by rabbits than by rats. ... Unchanged dichlobenil was not found in the urine but was found in the feces.|For more Absorption, Distribution and Excretion (Complete) data for DICHLOBENIL (8 total), please visit the HSDB record page.

In the unhydrolyzed urine of rats ... Metabolites were found: 2,6-dichloro-3-hydroxybenzonitrile and 2,6-dichloro-4-hydroxybenzonitrile and their glucuronides and sulfate, and the ester glucuronides of 2,6-dichlorobenzoic acid and 2,6-dichloro-3-hydroxybenzoic acid. An unknown aromatic acid and two sulfur containing metabolites--possibly mercapturic compounds--were also observed. ... Urine of rabbits & rats fed dichlobenil showed the presence of residues in amounts of 2% and 6%, respectively ... in the form of the 4-hydroxy analog; & 23% and 22%, respectively, in form of the 3-hydroxy analog. The hippurate conjugate was also observed ... .|When dichlobenil was applied to soil surrounding 8-yr-old apple trees ... leaves accumulated dichlobenil, BAM /2,6-dichlorobenzamide/, 2,6-dichloro-3-(& 4-) hydroxybenzamide, 2,6-dichloro-3-(& 4-) hydroxybenzonitriles, & some unidentified material ... /In Phaseolus vulgaris l/ seedlings ... hydroxylation, followed by conjugation, is primary pathway. In addition to formation of 2,6-dichloro-3-(& 4-) hydroxybenzonitrile ... hydrolysis of dichlobenil to 2,6-dichlorbenzamide & 2,6-dichlorobenzoic acid also occurred. Seedlings of wheat ... & rice ... were exposed to labeled dichlobenil by immersion of their roots in /water/ solution ... In wheat /& in rice at lower rate it/ ... was hydroxylated to 3- and 4-hydroxy analogs & converted to soluble and insoluble conjugates.|When dichlobenil was applied to water cress, Rorippa nasturtium-aquaticum, chromatography indicated the presence of the 3-OH and 4-OH analogs in roots and 2,6-dichlorobenzamide in the stems. The 3-OH and 4-OH compounds seemed to be present in stems and roots of narrow-leafed water parsnip, Berula erecta and 2,6-dichlorobenzamide possibly present in Berula erecta leaves. The 3-OH and 4-OH metabolites were present in all regions of reedgrass, Phragmites commums.|Hydrolysis of the nitrile group and hydroxylation at the 3-position of the phenyl ring of dichlobenil are the main metabolic routes in the initial degradation step, but all routes eventually yield the polar metabolite, 3-hydroxy-2,6-dichlorobenzoic acid.|For more Metabolism/Metabolites (Complete) data for DICHLOBENIL (9 total), please visit the HSDB record page.|2,6-dichlorobenzonitrile has known human metabolites that include 1,3-dichloro-7-oxabicyclo[4.1.0]hepta-3,5-diene-2-carbonitrile and 2,4-dichloro-7-oxabicyclo[4.1.0]hepta-2,4-diene-3-carbonitrile.

Dichlobenil acts primarily on growing points and root tips. Definite characteristics at the toxic level in intact plants include a rapid growth inhibition, followed by a gross disruption of tissues, notably in the meristems and phloem, which may result in the swelling or collapse of stem, root, and petiole, and a generalized brown discoloration, frequently accompanied by the exudation of gummy material from shoots.|Soil applied dichlobenil (2 lb/acre) destroyed phloem, cambium, and associated parenchyma in and above nodes of alligator weed ... Injury to inactive axillary bud tissues was limited... .|Selective systemic herbicide, absorbed by the roots and leaves, with rapid translocation acropetally and slower translocation basipetally. Inhibits actively dividing meristems and germination of seeds, and damages rhizomes. Has no effect on cell respiration or photosynthesis, but inhibits cellulose synthesis.|24 hr following injection of a single dose of the herbicide dichlobenil (2,6-dichlorobenzonitrile) in C57Bl/6 mice a steep dose-response curve for the histopathological toxicity in the olfactory mucosa was observed. 4 hr following injection of a toxic dose of (14)C-dichlobenil (12 mg/kg) the covalent binding in the olfactory mucosa was 26 times higher than that in the liver. A dose-dependent decrease of nonprotein sulfhydryls (mainly glutathione, GSH) in the olfactory mucosa was observed 2.5 hr following injection of dichlobenil (6, 12, 25 mg/kg). The synthetic GSH precursor N-acetyl-L-cysteine decreased both the dichlobenil-induced toxicity and the covalent binding, whereas N-acetyl-D-cysteine had no effect. No protective effects of the cyanide antidotes nitrite, thiosulfate, or superoxide dismutase on the dichlobenil-induced toxicity were observed. In mice given the GSH-depleting agent phorone and a subtoxic dose of dichlobenil (6 mg/kg), an extensive toxicity and an increased covalent binding in the olfactory mucosa were demonstrated. Autoradiography showed no change in the distribution of covalent (14)C dichlobenil binding to nontarget tissues of phorone-treated mice. In conclusion, the results demonstrate a relationship between the degrees of covalent binding, GSH depletion, and toxicity of dichlobenil in the olfactory mucosa. Hence, the level of GSH appears to be of importance for the dichlobenil-induced toxicity in the olfactory mucosa.|The metabolic activation of the herbicide dichlobenil (2,6-dichloro (ring-(14)C) benzonitrile) in the olfactory mucosa of C57BL mice and Sprague Dawley rats was examined. In homogenates of the olfactory mucosa (mouse 1000 x g supernatants; rat microsomes), dichlobenil was metabolized and covalently bound to protein. The apparent Km, Vmax and V/K values showed that the olfactory mucosa had both a higher affinity for dichlobenil and a higher capacity/mg protein to activate dichlobenil in comparison to the liver. The covalent binding was dependent on NADPH and was inhibited by the addition of dithionite, metyrapone and glutathione indicating an oxidative cytochrome P-450 dependent activation of dichlobenil into an electrophilic intermediate. The covalent binding was also inhibited by the addition of superoxide dismutase whereas catalase, mannitol or dimethylsulfoxide had no effect indicating the involvement of O2- but not of H2O2 or OH. in the activation. In explants of the olfactory mucosa incubated with (14)C dichlobenil a preferential covalent binding was observed in the Bowman's glands suggesting an activation of dichlobenil in these structures. The highly efficient metabolic activation of dichlobenil to reactive intermediates in the olfactory mucosa is suggested to be of importance for the potent dichlobenil-induced toxicity in this tissue.

SOLID: Harmful if swallowed. (USCG, 1999)

Call a physician. EYES: Flush with water. SKIN: Wash with water. INGESTION: Gastric lavage and symptomatic therapy. (USCG, 1999)

Fresh air, rest.

Remove contaminated clothes. Rinse and then wash skin with water and soap.

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Inhalation: /get/ fresh air and rest. Skin /exposure/: Remove contaminated clothes. Rinse and then wash skin with water and soap. Eye /exposure/: first rinse with plenty of water for several minute (remove contact lenses if easily possible), then take to a doctor. Ingestion: Rinse mouth. DO NOT induce vomiting. Refer for medical attention.|Basic treatment: Establish a patent airway. 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 normal saline 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 ... . /Poison A and B/|Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in respiratory arrest. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start an IV with D5W /SRP: "To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. Consider drug therapy for pulmonary edema ... . For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poison A and B/

/SIGNS AND SYMPTOMS/ Dichlobenil caused chloracne in six persons involved in the manufacture of Casoron. Symptoms were observed at different lag times for each individual, the longest being five months. Several hundred pinpoint open comedones and several closed comedones appeared on the forehead, masseteric, zygomatic, and suborbital regions, and occasionally an inflammatory papule or small pustule was noted. The usual forms of acne treatment did not produce improvement until the patient was withdrawn from contact with dichlobenil.|/SIGNS AND SYMPTOMS/ /Dichlobenil/ may have effects on the skin, resulting in chloracne from long-term or repeated exposure.|/SIGNS AND SYMPTOMS/ /Dichlobenil may cause/ cough /after/ inhalation and eye redness, and MAY BE ABSORBED /by/ skin.|/OTHER TOXICITY INFORMATION/ A harmful concentration of airborne particles can be reached quickly when dispersed.

2,6-dichlorobenzonitrile

The substance can be absorbed into the body by inhalation, through the skin and by ingestion.

Cough.

MAY BE ABSORBED!

Redness.

Essentially 100% as an herbicide

USEPA/OPP Pesticide Code 027401; Trade Names: Casoron, Prefix D, Nia 5996, H 133, Du-sprex, Norosac.|59% wettable powder; 75% granules.|Available formulations are 'Casoron' wp, 'Casoron g', containing 45% & 6.75% dichlobenil respectively.|Technical grade dichlobenil is > or =98% pure.|For more Formulations/Preparations (Complete) data for DICHLOBENIL (9 total), please visit the HSDB record page.

Applications using normal herbicidal rates remain effective for a period of 2-6 mo, under favorable conditions even for a period of 1 yr.|For germinating seeds, rhizomes, & young seedlings; early postemergence spring application in tolerant crops is recommended.|Recommended rates are: for selective post-emergence control on fruit & other crops 2.5-10 kg/hectare; for aquatic weed control 4.5-12 kg/hectare; for total weed control < -20 kg/hectare.|Some conifers are susceptible to dichlobenil vapor, due to their bark structure.|The maximum application rate was reduced in 1998 from 20 lbs ai/acre to 10 lbs ai/acre

Dichlobenil and its degradation product in soil, 2,6-dichlorobenzamide, were determined in aqueous samples by high performance liquid chromatography. Using a radial compression c18 column, the method gave a detection limit of 0.01 ppm for each compound without preliminary extraction or concentration.|Gas chromatography-mass spectrometry and electron capture detection were employed for qualitative analysis and quantitative determination of herbicides in water.|Method: AOAC 979.03; Procedure: Gas chromatography with flame ionization detection; Analyte: dichlobenil; Matrix: pesticide formulations; Detection Limit: not provided.|Method: USGS-NWQL O-1131-95; Procedure: high performance liquid chromatography; Analyte: dichlobenil; Matrix: filtered natural-water samples; Detection Limit: 0.012 ug/L.

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

Dichlobenil has known environmental transformation products that include 2,6-Dichlorobenzamide.|Dichlobenil has known environmental transformation products that include AE C653711 (2,6-Dichlorbenzamid).