N-Phenyl-p-phenylenediamine

H302 (97.2%): Harmful if swallowed [Warning Acute toxicity, oral]

H317 (97.4%): May cause an allergic skin reaction [Warning Sensitization, Skin]

H319 (31.6%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H400 (90.9%): Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

H410 (93.2%): Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]

P261, P264, P264+P265, P270, P272, P273, P280, P301+P317, P302+P352, P305+P351+P338, P321, P330, P333+P317, P337+P317, P362+P364, P391, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 680 reports by companies from 21 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.

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

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

H320: Causes eye irritation [Warning Serious eye damage/eye irritation]

H361: Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity]

H371: May cause damage to organs [Warning Specific target organ toxicity, single exposure]

P203, P260, P261, P264, P264+P265, P270, P272, P280, P301+P317, P302+P352, P305+P351+P338, P308+P316, P318, P321, P330, P333+P317, P337+P317, P362+P364, P405, and P501 (click each P-code to see the statement)

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)

Fresh air, rest. Refer for medical attention.

Remove contaminated clothes. Rinse skin with plenty of water or shower.

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

Rinse mouth. Give one or two glasses of water to drink. Do NOT induce vomiting. Refer for medical attention .

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)

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)

Use dry powder, carbon dioxide.

Excerpt from ERG Guide 153 [Substances - Toxic and/or Corrosive (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)

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting.

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.

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 chemical at ambient temperatures, and keep it away from oxidizing materials and acids. (NTP, 1992)

Separated from strong oxidants and strong acids. Dry.

skin absorption (H); sensitization of skin (SH); carcinogen category: 3

A harmful concentration of airborne particles can be reached quickly when dispersed, especially if powdered.

The substance is irritating to the skin and eyes. Ingestion could cause effects on the blood. This may result in the formation of methaemoglobin. Medical observation is indicated. The effects may be delayed.

Repeated or prolonged contact may cause skin sensitization.

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)

NO open flames.

PREVENT DISPERSION OF DUST! AVOID ALL CONTACT!

Use local exhaust or breathing protection.

Protective clothing. Protective gloves.

Wear safety spectacles or eye protection in combination with breathing protection if powder.

Do not eat, drink, or smoke during work. Wash hands before eating.

N-phenyl-p-phenylenediamine appears as odorless purple-black solid or flake or dark purple chips. (NTP, 1992)

Dry Powder; Liquid

Purple powder or needles; [HSDB]

PURPLE CRYSTALLINE POWDER OR NEEDLES

Needles (alcohol)

Purple powder

Purple needles

669 °F at 760 mmHg (NTP, 1992)

163 to 167 °F (NTP, 1992)

380 °F (NTP, 1992)

less than 1 mg/mL at 66 °F (NTP, 1992)

Slightly soluble in water, chloroform; very soluble in ethanol; soluble in diethyl ether, ligroin

Soluble in alcohol and acetone

Insoluble in water; soluble in oxygenated solvents

Solubility: 500 mg/L at 20 °C and pH 8.9

Solubility in water, g/100ml at 20 °C: 0.05

1.15 (NTP, 1992) - Denser than water; will sink

1.1 at 100 °C

1.09 g/cm³

0.0000121 [mmHg]

1.21X10-5 mm Hg at 25 °C (extrapolated)

Vapor pressure, Pa at 20 °C: 0.000076

2.4 (calculated)

When heated to decompostion it emits toxic fumes of NOx.

1.76X10-2 Pa.s at 25 °C

-6.29X10+9 J/kmol

9.26X10+7 J/kmol at 25 °C

3.08X10-2 N/m at 25 °C

pKa = 5.20 (conjugate acid)

143.1 Ų [M+H]+ [CCS Type: DT; Buffer gas: N2; Ionization: APCI+; Dataset: TOXCAST; Source Identifier: DTXSID7025895]

Heat of formation = 2.06X10+8 J/kmol; liquid molar volume = 0.188 cu m/kmol

Cosmetics ingredient -> Colorant

Cosmetic ingredients (N-Phenyl-p-Phenylenediamine) -> CIR (Cosmetic Ingredient Review)

Hair dyeing

Nitrogen Compounds -> Amines, Polyaromatic

Insoluble in water.

Amines, Aromatic

N-PHENYL-P-PHENYLENEDIAMINE is incompatible with strong oxidizers. It is also incompatible with strong acids. It may react with plastics. (NTP, 1992)

On the basis of the data included in this report, the CIR Expert Panel concludes that N-Phenyl-p-Phenylenediamine... safe for use in hair dyes at concentrations up to 1.7% (as the free base).

Safe for use in cosmetics, with qualifications

N-phenyl-p-phenylenediamine

TR-082: Bioassay of N-Phenyl-p-phenylenediamine for Possible Carcinogenicity (CASRN 101-54-2) (1978 )

03/06/78

No Evidence

It is concluded that under the conditions of this bioassay, N-phenyl-p-phenylenediamine was not carcinogenic for Fischer 344 rats or for B6C3F1 mice.

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

Redness. Pain.

Blue lips, fingernails and skin. Confusion. Convulsions. Dizziness. Headache. Nausea. Abdominal pain. Vomiting. Unconsciousness.

Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.

Methemoglobinemia - The presence of increased methemoglobin in the blood; the compound is classified as secondary toxic effect

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

LD50 Mouse oral 244 mg/kg

LD50 Rat Oral 720 mg/kg bw

LD50 Rabbit Dermal >5000 mg/kg bw

LD50 Rat oral 847 mg/kg bw

TREATMENT IS SYMPTOMATIC. WHENEVER HISTAMINE-LIKE EFFECTS PREDOMINATE, THERAPEUTIC TRIAL WITH AN ANTIHISTAMINIC IS SUGGESTED. /PRC: POTENTIAL METHEMOGLOBIN FORMER./ /PHENYLENEDIAMINE/

METHYLENE BLUE, ALONE OR IN COMBINATION WITH OXYGEN, IS INDICATED AS TREATMENT IN METHEMOGLOBINEMIIA.

/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. /Organic bases/Amines and related compounds/

/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 necessary. 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 mg/kg up to 200 ml of water for dilution if the patent can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . Cover skin burns with dry sterile dressings after decontamination ... . /Organic bases/Amines and related compounds/

/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 ... . 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 (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. If patient is unresponsive to these measures, vasopressors may be helpful. Watch for signs of fluid overload ... . Administer 1% solution methylene blue if patient is symptomatic with severe hypoxia, cyanosis, and cardiac compromise not responding to oxygen. DIRECT PHYSICIAN ORDER ONLY ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Organic bases/Amines and related compounds/

/HUMAN EXPOSURE STUDIES/ A study of contact dermatitis in Italian hairdressers was conducted in a cohort of 302 hairdressers (43 men and 259 women, mean age 24.6 years) who were treated for skin problems at Italian dermatology clinics over a 5 year period. Of these, 184 were patch tested with an Italian standard allergen series and a hairdresser's allergen series. ... The subjects had been employed as hairdressers a mean of 5.3 years. ... Among hair dye allergens, p-phenylenediamine, para-aminodiphenylamine, o-nitro-p-phenylenediamine, and para-toluenediamine caused a high incidence of positive reactions, 24.2, 10.6, 7.9, and 13.2%, respectively. ... It was concluded that a high proportion of hairdressers who seek treatment for skin problems have allergic contact dermatitis.

/HUMAN EXPOSURE STUDIES/ A cleaner at a chemical plant suffering from allergic skin reaction of the face, neck and arms was tested. Positive reaction to 0 25% test substance in petrolatum after 48 and 72 hr.

/HUMAN EXPOSURE STUDIES/ Cosmetic intolerance has been studied in 5202 patients; tested for possible contact dermatitis. Results: 107 (2.1%) showed positive reaction to the test substance; from 156 patients with pure allergy to cosmetics 5 (3.2%) -reacted positve to the test substance.

/HUMAN EXPOSURE STUDIES/ Tests were performed in 181 persons with confirmed group sensitization to aromatic amino compounds; test concentration 1% of the test substance; results: 96 patients (53%) showed positive reaction.

For more Human Toxicity Excerpts (Complete) data for P-AMINODIPHENYLAMINE (8 total), please visit the HSDB record page.

/LABORATORY ANIMALS: Acute Exposure/ Sensitization was obtained with 1 & 2% p-phenylenediamine in 62% of 160 animals tested. /p-Phenylenediamine/

/LABORATORY ANIMALS: Acute Exposure/ 0.5 g /of p-aminodiphenylamine was/ applied to the intact skin of 6 male and female New Zealand White rabbits; semi-occlusive; 4 hr exposure. /Test substance was found to be 'not irritating'./

/LABORATORY ANIMALS: Acute Exposure/ 0 5 g /of p-aminodiphenylamine was/ applied to the intact skin of 6 male and female New Zealand White rabbits; occlusive dressing; exposure 24 hr. /The test substance was found to be 'slightly irritating'./

/LABORATORY ANIMALS: Acute Exposure/ 3 female New Zealand White /rabbits/, weight about 3 kg; instillation of 100 mg solid /p-aminodiphenylamine/ into the conjunctival sac of one eye washed out with water after 24 hr; scored 1, 24, 48, 72 hr and 7 days after application. ... Primary irritation value 8.1 /(as discribed in the OECD guideline 405 on "Acute eye irritation/corrosion)/; all symptoms reversible after 72 hr no additional symptoms.

For more Non-Human Toxicity Excerpts (Complete) data for P-AMINODIPHENYLAMINE (26 total), please visit the HSDB record page.

The following link will take the user to the National Toxicology Program (NTP) Test Agent Search Results page, which tabulates all of the "Standard Toxicology & Carcinogenesis Studies", "Developmental Studies", and "Genetic Toxicity Studies" performed with this chemical. Clicking on the "Testing Status" link will take the user to the status (i.e., in review, in progress, in preparation, on test, completed, etc.) and results of all the studies that the NTP has done on this chemical.[Available from: http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm?fuseaction=ntpsearch.searchresults&searchterm=101-54-2]

A bioassay of N-phenyl-p-phenylenediamine for possible carcinogenicity was conducted by administering the test chemical in the diet to Fischer 344 rats and B6C3F1 mice. Groups of 50 rats of each sex were administered /the test cmpd/ at one of two doses, either 600 or 1,200 ppm, for 78 wk and were then observed for an additional 26 wk. Matched controls consisted of groups of 20 untreated rats of each sex. All surviving rats were /sacrificed/ at 104 wk. Groups of 50 mice of each sex were initially administered /the test cmpd/ at one of the following doses, either 2,500 or 5,000 ppm for the males and either 5,000 or 10,000 ppm for the females, for 31 wk. Because of toxicity ... the doses were lowered at that time and terminated at 48 wk. The animals were then observed for 43 additional wk. Time weighted avg doses during the period of administration were 2,057 or 4,114 ppm for the males and 3,672 or 8,170 ppm for the females. Matched controls consisted of groups of 20 untreated mice of each sex. All surviving mice were /sacrificed/ at 91 wk. ... Under the conditions of this bioassay, N-phenyl-p-phenylenediamine was not carcinogenic for Fischer 344 rats or B6C3F1 mice. Levels of Evidence of Carcinogenicity: Male Rats: Negative; Female Rats: Negative; Male Mice: Negative; Female Mice: Negative.

EC50; Species: Daphnia magna (Water flea, age <24 hr); Conditions: freshwater, static, pH 7.8-8.1, dissolved oxygen 96-99% saturated; Concentration: 1220 ug/L for 24 hr (95% confidence interval: 520-2920 ug/L); Effect: intoxication, immobilization /98% purity/

EC50; Species: Daphnia magna (Water flea, age <24 hr); Conditions: freshwater, renewal, pH 7.8-8.1, dissolved oxygen 96-99% saturated; Concentration: 370 ug/L for 48 hr; Effect: intoxication, immobilization /98% purity/

EC50; Species: Daphnia magna (Water flea); Conditions: static not aerated, 20.4 °C, pH 7.9 + or -0.1, dissolved oxygen 8.3-8.9 mg/L; Concentration: 4.1 mg/L for 24 hr; Effect: immobilization /98.8% purity/

EC50; Species: Daphnia magna (Water flea); Conditions: static unaerated, 19.8-21.5 °C, pH 7.5-9.7, dissolved oxygen 8.4-14.4 mg/L; Concentration: 0.1 mg/L for 21 days; Effect: reproduction rate /98.8% purity/

For more Ecotoxicity Values (Complete) data for P-AMINODIPHENYLAMINE (7 total), please visit the HSDB record page.

This substance may be hazardous to the environment. Special attention should be given to aquatic organisms.

EC50; Species: Daphnia magna (Water flea, age <24 hr); Conditions: freshwater, static, pH 7.8-8.1, dissolved oxygen 96-99% saturated; Concentration: 1220 ug/L for 24 hr (95% confidence interval: 520-2920 ug/L); Effect: intoxication, immobilization /98% purity/

EC50; Species: Daphnia magna (Water flea, age <24 hr); Conditions: freshwater, renewal, pH 7.8-8.1, dissolved oxygen 96-99% saturated; Concentration: 370 ug/L for 48 hr; Effect: intoxication, immobilization /98% purity/

EC50; Species: Daphnia magna (Water flea); Conditions: static not aerated, 20.4 °C, pH 7.9 + or -0.1, dissolved oxygen 8.3-8.9 mg/L; Concentration: 4.1 mg/L for 24 hr; Effect: immobilization /98.8% purity/

EC50; Species: Daphnia magna (Water flea); Conditions: static unaerated, 19.8-21.5 °C, pH 7.5-9.7, dissolved oxygen 8.4-14.4 mg/L; Concentration: 0.1 mg/L for 21 days; Effect: reproduction rate /98.8% purity/

For more Ecotoxicity Values (Complete) data for P-AMINODIPHENYLAMINE (7 total), please visit the HSDB record page.

This substance may be hazardous to the environment. Special attention should be given to aquatic organisms.

p-Aminodiphenylamine's production and use as a dye intermediate may result in its release to the environment through various waste streams. If released to air, a vapor pressure of 1.21X10-5 mm Hg at 25 °C indicates p-aminodiphenylamine will exist in both the vapor and particulate phases in the atmosphere. Vapor-phase p-aminodiphenylamine 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 1.9 hours. Particulate-phase p-aminodiphenylamine will be removed from the atmosphere by wet or dry deposition. p-Aminodiphenylamine contains chromophores that absorb at wavelengths >290 nm and therefore may be susceptible to direct photolysis by sunlight. If released to soil, p-aminodiphenylamine is expected to have slight mobility based upon an estimated Koc of 3.1X10+3. The pKa of p-aminodiphenylamine is 5.20, indicating that this compound will partially exist in cation form in the environment and cations generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 3.7X10-10 atm-cu m/mole. p-Aminodiphenylamine is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Reported inherent biodegradation values of 28% after 20 days in an adapted activated sludge and 58% after 3 hours in a mixed, non-adapted activated sludge inoculum suggest that biodegradation in the aquatic environment may be an important fate process. If released into water, p-aminodiphenylamine is expected to adsorb to suspended solids and sediment based upon the estimated Koc. Reported inherent biodegradation values of 28% after 20 days in an adapted activated sludge and 58% after 3 hours in a mixed, non-adapted activated sludge inoculum suggest that biodegradation in the aquatic environment may be an important fate process. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. A pKa of 5.20 indicates p-aminodiphenylamine will exist partially in the cation form at pH values of 5 to 9 and therefore volatilization from water surfaces is not expected to be an important fate process. An estimated BCF of 5.1 suggests the potential for bioconcentration in aquatic organisms is low. 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 p-aminodiphenylamine may occur through inhalation of dust and dermal contact with this compound at workplaces where p-aminodiphenylamine is produced or used. The general population may be exposed to p-aminodiphenylamine via dermal contact with consumer products containing p-aminodiphenylamine. (SRC)

p-Aminodiphenylamine's production and use as a dye intermediate(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 3.1X10+3(SRC), determined from a structure estimation method(2), indicates that p-aminodiphenylamine is expected to have slight mobility in soil(SRC). The pKa of p-aminodiphenylamine is 5.20(3), indicating that this compound will partially exist in cation form in the environment and cations generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4). Volatilization of p-aminodiphenylamine from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 3.7X10-10 atm-cu m/mole(SRC), using a fragment constant estimation method(5). p-Aminodiphenylamine is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.21X10-5 mm Hg at 25 °C(6). Reported inherent biodegradation values of 28% after 20 days in an adapted activated sludge and 58% after 3 hours in a mixed, non-adapted activated sludge inoculum(7) suggest that biodegradation in the aquatic environment may be an important fate process(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 3.1X10+3(SRC), determined from a structure estimation method(2), indicates that p-aminodiphenylamine is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 3.7X10-10 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). A pKa of 5.20(5) indicates p-aminodiphenylamine will exist partially in the cation form at pH values of 5 to 9 and therefore volatilization from water surfaces is not expected to be an important fate process(6). According to a classification scheme(7), an estimated BCF of 5.1(SRC), from an estimated log Kow of 1.82(8) and a regression-derived equation(9), suggests the potential for bioconcentration in aquatic organisms is low. Reported inherent biodegradation values of 28% after 20 days in an adapted activated sludge and 58% after 3 hours in a mixed, non-adapted activated sludge inoculum(10) suggest that biodegradation in the aquatic environment may be an important fate process(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), p-aminodiphenylamine, which has a vapor pressure of 1.21X10-5 mm Hg at 25 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase p-aminodiphenylamine 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 1.9 hours(SRC), calculated from its rate constant of 2.0X10-10 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase p-aminodiphenylamine may be removed from the air by wet or dry deposition(SRC). p-Aminodiphenylamine contains chromophores that absorb at wavelengths >290 nm(4) and therefore may be susceptible to direct photolysis by sunlight(SRC).

AEROBIC: p-Aminodiphenylamine, present at 2.4 mg/L biodegraded 0, 24, and 28% in 5, 10, and 20 days, respectively, using an adapted activated sludge inoculum in a DEV test(1). p-Aminodiphenylamine, present at 100 mg DOC/L, reached 58% DOC after 3 hours using a mixed, non-adapted activated sludge inoculum in a Zahn-Wellens test(1).

The rate constant for the vapor-phase reaction of p-aminodiphenylamine with photochemically-produced hydroxyl radicals has been estimated as 2.0X10-10 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 1.9 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). p-Aminodiphenylamine is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(2). p-Aminodiphenylamine contains chromophores that absorb at wavelengths >290 nm(2) and therefore may be susceptible to direct photolysis by sunlight(SRC).

An estimated BCF of 5.1 was calculated for p-aminodiphenylamine(SRC), using an estimated log Kow of 1.82(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of p-aminodiphenylamine can be estimated to be 3.1X10+3(SRC). According to a classification scheme(2), this estimated Koc value suggests that p-aminodiphenylamine is expected to have slight mobility in soil. The pKa of p-aminodiphenylamine is 5.20(3), indicating that this compound will partially exist in cation form in the environment and cations generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4).

The Henry's Law constant for p-aminodiphenylamine is estimated as 3.7X10-10 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that p-aminodiphenylamine is expected to be essentially nonvolatile from water surfaces(2). A pKa of 5.20(2) indicates p-aminodiphenylamine will exist partially in the cation form at pH values of 5 to 9 and therefore volatilization from water surfaces or moist soil is not expected to be an important fate process(3). p-Aminodiphenylamine is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.21X10-5 mm Hg(3).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 4,356 workers (530 of these were female) were potentially exposed to p-aminodiphenylamine in the US(1). Occupational exposure to p-aminodiphenylamine may occur through inhalation of dust and dermal contact with this compound at workplaces where p-aminodiphenylamine is produced or used. The general population may be exposed to p-aminodiphenylamine via dermal contact with consumer products containing p-aminodiphenylamine(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.