1,2-Dimethyl-3-nitrobenzene

This chemical does not meet GHS hazard criteria for 24.8% (38 of 153) of reports.

H411 (71.9%): Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

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

Aggregated GHS information provided per 153 reports by companies from 5 notifications to the ECHA C&L Inventory.

Reported as not meeting GHS hazard criteria per 38 of 153 reports by companies.

There are 4 notifications provided by 115 of 153 reports by companies with hazard statement code(s).

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.

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment.

INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.

INGESTION: DO NOT INDUCE VOMITING. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. Be prepared to transport the victim to a hospital if advised by a physician. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. IMMEDIATELY transport the victim to a hospital. (NTP, 1992)

Excerpt from ERG Guide 152 [Substances - Toxic (Combustible)]:

Refer to the "General First Aid" section. Specific First Aid: Removal of solidified molten material from skin requires medical assistance. (ERG, 2024)

Fires involving this material can be controlled with a dry chemical, carbon dioxide, or Halon extinguisher. A water spray may also be used. (NTP, 1992)

Excerpt from ERG Guide 152 [Substances - Toxic (Combustible)]:

SMALL FIRE: Dry chemical, CO2 or water spray.

LARGE FIRE: Water spray, fog or regular foam. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal. Avoid aiming straight or solid streams directly onto the product.

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers. 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. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2024)

Excerpt from ERG Guide 152 [Substances - Toxic (Combustible)]:

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)

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

SMALL SPILLS AND LEAKAGE: Should a spill occur while you are handling this chemical, FIRST REMOVE ALL SOURCES OF IGNITION, then you should dampen the solid spill material with 60-70% ethanol and transfer the dampened material to a suitable container. Use absorbent paper dampened with 60-70% ethanol to pick up any remaining material. Seal the absorbent paper, and any of your clothes, which may be contaminated, in a vapor-tight plastic bag for eventual disposal. Solvent wash all contaminated surfaces with 60-70% ethanol followed by washing with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.

STORAGE PRECAUTIONS: You should store this material under ambient temperatures. STORE AWAY FROM SOURCES OF IGNITION. (NTP, 1992)

Excerpt from ERG Guide 152 [Substances - Toxic (Combustible)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Cover with plastic sheet to prevent spreading. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. (ERG, 2024)

6.3 [mg/m3]

70 [mg/m3]

420 [mg/m3]

RECOMMENDED RESPIRATOR: Where the neat test chemical is weighed and diluted, wear a NIOSH-approved half face respirator equipped with an organic vapor/acid gas cartridge (specific for organic vapors, HCl, acid gas and SO2) with a dust/mist filter. (NTP, 1992)

Excerpt from ERG Guide 152 [Substances - Toxic (Combustible)]:

Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE. Structural firefighters' protective clothing provides thermal protection but only limited chemical protection. (ERG, 2024)

1,2-dimethyl-3-nitrobenzene is a yellow liquid. (NTP, 1992)

Nitroxylenes appears as yellow crystalline solids or liquids. Insoluble in water and combustible. Toxic by inhalation and skin absorption. Produces toxic oxides of nitrogen during combustion.

Pale yellow oil

473 °F at 760 mmHg (NTP, 1992)

240 °C @760 [mm Hg]

45 to 48 °F (NTP, 1992)

225 °F (NTP, 1992)

less than 1 mg/mL at 70 °F (NTP, 1992)

Soluble in most organic solvents

Soluble in ethanol and carbon tetrachloride

1.1402 at 68 °F (NTP, 1992) - Denser than water; will sink

1.1402 g/cu cm at 20 °C

1.1402 @ 20°C

5.22 (NTP, 1992) - Heavier than air; will sink (Relative to Air)

0.0172 mm Hg at 25 °C /extrapolated/

log Kow = 2.83

Index of refraction: 1.5441 at 20 °C

Boiling point

Chemical shift

Heat of sublimation

Lineshape

Vapor pressure

Insoluble in water.

Flammable. Insoluble in water.

Nitro, Nitroso, Nitrate, and Nitrite Compounds, Organic

Explosive

Strong Oxidizing Agent

1,2-DIMETHYL-3-NITROBENZENE is incompatible with strong oxidizers and strong bases (NTP, 1992).

Aromatic nitro compounds, such as NITROXYLENES, range from slight to strong oxidizing agents. If mixed with reducing agents, including hydrides, sulfides and nitrides, they may begin a vigorous reaction that culminates in a detonation. The aromatic nitro compounds may explode in the presence of a base such as sodium hydroxide or potassium hydroxide even in the presence of water or organic solvents. The explosive tendencies of aromatic nitro compounds are increased by the presence of multiple nitro groups.

LD50 Rat oral (female) 2110 mg/kg body weight

LD50 Rat (male) oral 2380 mg/kg body weight

/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/

/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). 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 0.9% saline (NS) 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 ... . /Poisons A and B/

/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/

/LABORATORY ANIMALS: Acute Exposure/ Exposure of rabbit skin to 3-nitro-1,2-dimethylbenzene leads to slight, transient inflammatory irritation. Similarly, the substance causes transient inflammatory effects on the conjunctiva and iris of the eye. The product has been evaluated as not irritating in accordance with EC classification criteria in both studies.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ On repeated administration in the diet of 0, 200, 1000 or 5000 ppm for 5 days or of 0, 100, 500 or 2500 ppm for 28 days (equivalent to 0, 20, 100 and 500 mg/kg body weight/day and 0, 10, 50 and 250 mg/kg body weight/day, respectively), reduced weight gain and reduced feed intake were found in both sexes at 5000 ppm in the range-finding study and at 2500 ppm in the main study. After administration for 5 days, the relative liver weight was dose-dependently increased in the males in all treated groups. No effects were found at post-mortem. Functional disturbances of the liver were found in males and females after administration of 2500 ppm for 4 weeks (decrease in total protein and effects on alanine aminotransferase activity and the albumin-globulin quotient). However, no effects on liver weight or histologically detectable damage to the liver were seen. The no toxic effect level derived from the 28-day study is 500 ppm (equivalent to ca. 50 mg/kg body weight/day).

/GENOTOXICITY/ 3-Nitro-1,2-dimethylbenzene is not mutagenic in the Salmonella/microsome test. In the chromosome aberration test in V79 cells in vitro, 3-nitro-1,2-dimethylbenzene induces structural chromosome aberrations.

/GENOTOXICITY/ Ames assay (preincubation) in Salmonella typhimurium TA97, TA98, TA100 and TA1535 without and with S-9 (rat liver, 10%, Aroclor 1254 induced ): positive.

EC50; Species: Chlorella pyrenoidosa (Green Algae) exponential growth phase, 2 X10+8 cells/mL; Conditions: freshwater, static, 25 °C, pH 6.6; Concentration: 6300 ug/L for 96 hr (95% confidence interval: 4100-9800 ug/L); Effect: population changes, general /formulation/

LC50; Species: Daphnia magna (Waterflea) age <24 hr; Conditions: freshwater, static, 20 °C, pH 8.2, hardness 250 mg/L CaCO3, dissolved oxygen >6.5 mg/L; Concentration: 4200 ug/L for 48 hr (95% confidence interval: 3200-5600 ug/L) /formulation/

LC50; Species: Daphnia magna (Waterflea) age <24 hr; Conditions: freshwater, static, 20 °C, pH 8.2, hardness 250 mg/L CaCO3, dissolved oxygen >6.5 mg/L; Concentration: 3800 ug/L for 21 days (95% confidence interval: 3600-4000 ug/L) /formulation/

LC50; Species: Poecilia reticulata (Guppy) age 3-4 wk; Conditions: freshwater, static, 25 °C, pH 8.2, hardness 250 mg/L CaCO3; Concentration: 6200 ug/L for 14 days /formulation/

1,2-Dimethyl-3-nitrobenzene's production and use as a starting material for the production of agrochemicals and as an intermediate for the production of dyes and colorants may result in its release to the environment through various waste streams. If released to air, an extrapolated vapor pressure of 0.0172 mm Hg at 25 °C indicates 1,2-dimethyl-3-nitrobenzene will exist solely as a vapor in the atmosphere. Vapor-phase 1,2-dimethyl-3-nitrobenzene 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 about 15 days. Methylnitrobenzenes have measurable quantum yields at 313 nm and therefore are susceptible to direct photolysis in sunlight. If released to soil, 1,2-dimethyl-3-nitrobenzene is expected to have low mobility based upon an estimated Koc of 606. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 5.11X10-5 atm-cu m/mole. 1,2-Dimethyl-3-nitrobenzene is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Utilizing the Japanese MITI test, 0% of the Theoretical BOD was reached in 4 weeks indicating that biodegradation is not an important environmental fate process in soil or water. However, studies of analogous 2- and 4-methylnitrobenzene have shown that biodegradation of these compounds in acclimated media can be relatively fast with 98-100% degradation within a few days to a few weeks. If released into water, 1,2-dimethyl-3-nitrobenzene is expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 25 hours and 11 days, respectively. A BCF of 724 suggests bioconcentration in aquatic organisms is high. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to 1,2-dimethyl-3-nitrobenzene may occur through dermal contact with this compound at workplaces where 1,2-dimethyl-3-nitrobenzene is produced or used. (SRC)

1,2-Dimethyl-3-nitrobenzene's production and use as a starting material for the production of agrochemicals and as an intermediate for the production of dyes and colorants(1) may result in its release to the environment through various waste streams(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 606(SRC), determined from a structure estimation method(2), indicates that 1,2-dimethyl-3-nitrobenzene is expected to have low mobility in soil(SRC). Volatilization of 1,2-dimethyl-3-nitrobenzene from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 5.11X10-5 atm-cu m/mole(SRC), using a fragment constant estimation method(2). 1,2-Dimethyl-3-nitrobenzene is not expected to volatilize from dry soil surfaces(SRC) based upon an extrapolated vapor pressure of 0.0172 mm Hg at 25 °C(3). Utilizing the Japanese MITI test, 0% of the Theoretical BOD was reached in 4 weeks(4) indicating that biodegradation is not an important environmental fate process in soil. However, studies of analogous 2- and 4-methylnitrobenzene have shown that biodegradation of these compounds in acclimated media can be relatively fast with 98-100% degradation within a few days to a few weeks(5-7).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 606(SRC), determined from a structure estimation method(2), indicates that 1,2-dimethyl-3-nitrobenzene is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 5.11X10-5 atm-cu m/mole(SRC), developed using a fragment constant estimation method(2). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 25 hours and 11 days, respectively(SRC). According to a classification scheme(4), a BCF of 724(5) suggests the potential for bioconcentration in aquatic organisms is high. Utilizing the Japanese MITI test, 0% of the Theoretical BOD was reached in 4 weeks(6) indicating that biodegradation is not an important environmental fate process in water. However, studies of analogous 2- and 4-methylnitrobenzene have shown that biodegradation of these compounds in acclimated media can be relatively fast with 98-100% degradation within a few days to a few weeks(7-9).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 1,2-dimethyl-3-nitrobenzene, which has an extrapolated vapor pressure of 0.0172 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 1,2-dimethyl-3-nitrobenzene is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be about 15 days(SRC), calculated from its rate constant of 1.05X10-12 cu cm/molecule-sec at 25 °C(SRC), determined using a structure estimation method(3). By analogy to methylnitrobenzenes(4), 1,2-dimethyl-3-nitrobenzene is expected to be susceptible to direct photolysis in sunlight(SRC).

AEROBIC: 1,2-Dimethyl-3-nitrobenzene, present at 100 mg/L, reached 0% of its theoretical BOD in 4 weeks using an activated sludge inoculum at 30 mg/L in the Japanese MITI test (OECD TG 301C) that suggests the compound is not readily biodegradable(1). This Japanese MITI test yields similar results for 2-methylnitrobenzene and 4-methylnitrobenzene(1); however, other biodegradation screening tests have shown that biodegradation of these compounds in acclimated media (activated sludge, soil, water) can be relatively fast with 98-100% degradation within a few days to few weeks(2-4).

The rate constant for the vapor-phase reaction of 1,2-dimethyl-3-nitrobenzene with photochemically-produced hydroxyl radicals has been estimated as 1.05X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 15 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 1,2-Dimethyl-3-nitrobenzene is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(2). Methylnitrobenzenes have measurable quantum yields at 313 nm and therfore are susceptible to direct photolysis in sunlight(3). By analogy, 1,2-dimethyl-3-nitrobenzene is expected to be susceptible to direct photolysis(SRC).

A log BCF of 2.86 (BCF = 724) for 1,2-dimethyl-3-nitrobenzene was measured in guppies (Poecilla reticulata) during a 3-day static-flow test, measurement based on a fat-weight basis(1). According to a classification scheme(2), this log BCF suggests bioconcentration in aquatic organisms is high(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of 1,2-dimethyl-3-nitrobenzene can be estimated to be 606(SRC). According to a classification scheme(2), this estimated Koc value suggests that 1,2-dimethyl-3-nitrobenzene is expected to have low mobility in soil.

The Henry's Law constant for 1,2-dimethyl-3-nitrobenzene is estimated as 5.11X10-5 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that 1,2-dimethyl-3-nitrobenzene 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 25 hours(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 11 days(SRC). 1,2-Dimethyl-3-nitrobenzene's Henry's Law constant indicates that some volatilization from moist soil surfaces may occur(SRC). 1,2-Dimethyl-3-nitrobenzene is not expected to volatilize from dry soil surfaces(SRC) based upon an extrapolated vapor pressure of 0.0172 mm Hg at 25 °C(3).

According to the 2006 TSCA Inventory Update Reporting data, the number of persons reasonably likely to be exposed in the industrial manufacturing, processing, and use of 1,2-dimethyl-3-nitrobenzene is 1 to 99; the data may be greatly underestimated(1).

Occupational exposure to 1,2-dimethyl-3-nitrobenzene may occur through dermal contact with this compound at workplaces where 1,2-dimethyl-3-nitrobenzene is produced or used. (SRC)

EC50; Species: Chlorella pyrenoidosa (Green Algae) exponential growth phase, 2 X10+8 cells/mL; Conditions: freshwater, static, 25 °C, pH 6.6; Concentration: 6300 ug/L for 96 hr (95% confidence interval: 4100-9800 ug/L); Effect: population changes, general /formulation/

LC50; Species: Daphnia magna (Waterflea) age <24 hr; Conditions: freshwater, static, 20 °C, pH 8.2, hardness 250 mg/L CaCO3, dissolved oxygen >6.5 mg/L; Concentration: 4200 ug/L for 48 hr (95% confidence interval: 3200-5600 ug/L) /formulation/

LC50; Species: Daphnia magna (Waterflea) age <24 hr; Conditions: freshwater, static, 20 °C, pH 8.2, hardness 250 mg/L CaCO3, dissolved oxygen >6.5 mg/L; Concentration: 3800 ug/L for 21 days (95% confidence interval: 3600-4000 ug/L) /formulation/

LC50; Species: Poecilia reticulata (Guppy) age 3-4 wk; Conditions: freshwater, static, 25 °C, pH 8.2, hardness 250 mg/L CaCO3; Concentration: 6200 ug/L for 14 days /formulation/

1,2-Dimethyl-3-nitrobenzene's production and use as a starting material for the production of agrochemicals and as an intermediate for the production of dyes and colorants may result in its release to the environment through various waste streams. If released to air, an extrapolated vapor pressure of 0.0172 mm Hg at 25 °C indicates 1,2-dimethyl-3-nitrobenzene will exist solely as a vapor in the atmosphere. Vapor-phase 1,2-dimethyl-3-nitrobenzene 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 about 15 days. Methylnitrobenzenes have measurable quantum yields at 313 nm and therefore are susceptible to direct photolysis in sunlight. If released to soil, 1,2-dimethyl-3-nitrobenzene is expected to have low mobility based upon an estimated Koc of 606. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 5.11X10-5 atm-cu m/mole. 1,2-Dimethyl-3-nitrobenzene is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Utilizing the Japanese MITI test, 0% of the Theoretical BOD was reached in 4 weeks indicating that biodegradation is not an important environmental fate process in soil or water. However, studies of analogous 2- and 4-methylnitrobenzene have shown that biodegradation of these compounds in acclimated media can be relatively fast with 98-100% degradation within a few days to a few weeks. If released into water, 1,2-dimethyl-3-nitrobenzene is expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 25 hours and 11 days, respectively. A BCF of 724 suggests bioconcentration in aquatic organisms is high. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to 1,2-dimethyl-3-nitrobenzene may occur through dermal contact with this compound at workplaces where 1,2-dimethyl-3-nitrobenzene is produced or used. (SRC)

1,2-Dimethyl-3-nitrobenzene's production and use as a starting material for the production of agrochemicals and as an intermediate for the production of dyes and colorants(1) may result in its release to the environment through various waste streams(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 606(SRC), determined from a structure estimation method(2), indicates that 1,2-dimethyl-3-nitrobenzene is expected to have low mobility in soil(SRC). Volatilization of 1,2-dimethyl-3-nitrobenzene from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 5.11X10-5 atm-cu m/mole(SRC), using a fragment constant estimation method(2). 1,2-Dimethyl-3-nitrobenzene is not expected to volatilize from dry soil surfaces(SRC) based upon an extrapolated vapor pressure of 0.0172 mm Hg at 25 °C(3). Utilizing the Japanese MITI test, 0% of the Theoretical BOD was reached in 4 weeks(4) indicating that biodegradation is not an important environmental fate process in soil. However, studies of analogous 2- and 4-methylnitrobenzene have shown that biodegradation of these compounds in acclimated media can be relatively fast with 98-100% degradation within a few days to a few weeks(5-7).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 606(SRC), determined from a structure estimation method(2), indicates that 1,2-dimethyl-3-nitrobenzene is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 5.11X10-5 atm-cu m/mole(SRC), developed using a fragment constant estimation method(2). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 25 hours and 11 days, respectively(SRC). According to a classification scheme(4), a BCF of 724(5) suggests the potential for bioconcentration in aquatic organisms is high. Utilizing the Japanese MITI test, 0% of the Theoretical BOD was reached in 4 weeks(6) indicating that biodegradation is not an important environmental fate process in water. However, studies of analogous 2- and 4-methylnitrobenzene have shown that biodegradation of these compounds in acclimated media can be relatively fast with 98-100% degradation within a few days to a few weeks(7-9).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 1,2-dimethyl-3-nitrobenzene, which has an extrapolated vapor pressure of 0.0172 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 1,2-dimethyl-3-nitrobenzene is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be about 15 days(SRC), calculated from its rate constant of 1.05X10-12 cu cm/molecule-sec at 25 °C(SRC), determined using a structure estimation method(3). By analogy to methylnitrobenzenes(4), 1,2-dimethyl-3-nitrobenzene is expected to be susceptible to direct photolysis in sunlight(SRC).

AEROBIC: 1,2-Dimethyl-3-nitrobenzene, present at 100 mg/L, reached 0% of its theoretical BOD in 4 weeks using an activated sludge inoculum at 30 mg/L in the Japanese MITI test (OECD TG 301C) that suggests the compound is not readily biodegradable(1). This Japanese MITI test yields similar results for 2-methylnitrobenzene and 4-methylnitrobenzene(1); however, other biodegradation screening tests have shown that biodegradation of these compounds in acclimated media (activated sludge, soil, water) can be relatively fast with 98-100% degradation within a few days to few weeks(2-4).

The rate constant for the vapor-phase reaction of 1,2-dimethyl-3-nitrobenzene with photochemically-produced hydroxyl radicals has been estimated as 1.05X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 15 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 1,2-Dimethyl-3-nitrobenzene is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(2). Methylnitrobenzenes have measurable quantum yields at 313 nm and therfore are susceptible to direct photolysis in sunlight(3). By analogy, 1,2-dimethyl-3-nitrobenzene is expected to be susceptible to direct photolysis(SRC).

A log BCF of 2.86 (BCF = 724) for 1,2-dimethyl-3-nitrobenzene was measured in guppies (Poecilla reticulata) during a 3-day static-flow test, measurement based on a fat-weight basis(1). According to a classification scheme(2), this log BCF suggests bioconcentration in aquatic organisms is high(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of 1,2-dimethyl-3-nitrobenzene can be estimated to be 606(SRC). According to a classification scheme(2), this estimated Koc value suggests that 1,2-dimethyl-3-nitrobenzene is expected to have low mobility in soil.

The Henry's Law constant for 1,2-dimethyl-3-nitrobenzene is estimated as 5.11X10-5 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that 1,2-dimethyl-3-nitrobenzene 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 25 hours(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 11 days(SRC). 1,2-Dimethyl-3-nitrobenzene's Henry's Law constant indicates that some volatilization from moist soil surfaces may occur(SRC). 1,2-Dimethyl-3-nitrobenzene is not expected to volatilize from dry soil surfaces(SRC) based upon an extrapolated vapor pressure of 0.0172 mm Hg at 25 °C(3).

According to the 2006 TSCA Inventory Update Reporting data, the number of persons reasonably likely to be exposed in the industrial manufacturing, processing, and use of 1,2-dimethyl-3-nitrobenzene is 1 to 99; the data may be greatly underestimated(1).

Occupational exposure to 1,2-dimethyl-3-nitrobenzene may occur through dermal contact with this compound at workplaces where 1,2-dimethyl-3-nitrobenzene is produced or used. (SRC)

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