caprolactam

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

H315: Causes skin irritation [Warning Skin corrosion/irritation]

H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H332: Harmful if inhaled [Warning Acute toxicity, inhalation]

H335: May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

P261, P264, P264+P265, P270, P271, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, P317, P319, P321, P330, P332+P317, P337+P317, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)

This chemical does not meet GHS hazard criteria for < 0.1% (1 of 1874) of reports.

H302 (99.9%): Harmful if swallowed [Warning Acute toxicity, oral]

H315 (99.9%): Causes skin irritation [Warning Skin corrosion/irritation]

H319 (99.9%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H332 (99.9%): Harmful if inhaled [Warning Acute toxicity, inhalation]

H335 (95.8%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

Aggregated GHS information provided per 1874 reports by companies from 31 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Reported as not meeting GHS hazard criteria per 1 of 1874 reports by companies.

There are 30 notifications provided by 1873 of 1874 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.

H312: Harmful in contact with skin [Warning Acute toxicity, dermal]

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]

H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

P203, P260, P261, P264, P264+P265, P270, P271, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, P308+P316, P317, P318, P319, P321, P330, P332+P317, P337+P317, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)

H316: Causes mild skin irritation [Warning Skin corrosion/irritation]

H336: May cause drowsiness or dizziness [Warning Specific target organ toxicity, single exposure; Narcotic effects]

H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]

P260, P261, P264, P264+P265, P270, P271, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, P308+P316, P317, P319, P321, P330, P332+P317, P337+P317, P362+P364, P403+P233, P405, 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.

Rinse with plenty of water (remove contact lenses if easily possible). Refer for medical attention.

Rinse mouth. 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)

(General first aid procedures)

Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.

Skin: Water wash immediately - If this chemical contacts the skin, immediately wash the contaminated skin with water. If this chemical penetrates the clothing, immediately remove the clothing and wash the skin with water. If symptoms occur after washing, get medical attention immediately.

Breathing: Respiratory support

Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately.

Use foam, powder, carbon dioxide, water in large amounts.

Let solidify. 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. Wash away remainder with plenty of water.

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

Controlled incineration (oxides of nitrogen are removed from the effluent gas by scrubbers and/or thermal devices). Also caprolactam may be recovered from caprolactam still bottoms or nylon waste. Recommendable method: Incineration.

The following wastewater treatment technologies have been investigated for caprolactam: biological treatment.

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

ALL VESSELS & PIPING SHOULD BE REGULARLY CHECKED FOR LEAKS ... EXHAUST VENTILATION SHOULD BE INSTALLED.

CONCN OF.../60 MG/CU M SHOULD/ BE AVOIDED, & HENCE WORKSHOPS SHOULD BE EFFECTIVELY VENTILATED.

For more Preventive Measures (Complete) data for CAPROLACTAM (7 total), please visit the HSDB record page.

Separated from strong oxidants. Dry.

2.0 [mg/m3], inhalable fraction[German Research Foundation (DFG)]

3.0 [mg/m3]

60 [mg/m3]

360 [mg/m3]

1 mg/m³ (dust), 0.22 ppm (1 mg/m³) (vapor)

Dust: TWA 1 mg/m3 ST 3 mg/m3 Vapor: TWA 0.22 ppm (1 mg/m3) ST 0.66 ppm (3 mg/m3)

none See Appendix G

See: IDLH INDEX

5.0 [mg/m3], inhalable fraction and vapor

8 hr Time Weighted Avg (TWA): 5 mg/cu m. /Inhalable fraction and vapor/

Excursion Limit Recommendation: Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a work day, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded.

A5; Not suspected as a human carcinogen.

5 mg/m³ (inhalable fraction and vapor) [1997]

(inhalable fraction): 5 mg/m

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

The substance is irritating to the skin, eyes and respiratory tract. The substance may cause effects on the central nervous system.

Repeated or prolonged contact with skin may cause dermatitis. The substance may have effects on the nervous system and liver.

Excerpt from NIOSH Pocket Guide for Caprolactam:

Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact.

Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact.

Wash skin: WHEN CONTAMINATED - The worker should immediately wash the skin when it becomes contaminated.

Remove: WHEN WET OR CONTAMINATED - Work clothing that becomes wet or significantly contaminated should be removed and replaced.

Change: DAILY - Workers whose clothing may have become contaminated should change into uncontaminated clothing before leaving the work premises. (NIOSH, 2024)

WORKERS SHOULD BE SUPPLIED WITH SUITABLE PROTECTIVE CLOTHING INCL ... GLOVES & EYE-WEAR; RESP PROTECTIVE EQUIPMENT MAY BE NECESSARY.

Wear appropriate personal protective clothing to prevent skin contact.

Wear appropriate eye protection to prevent eye contact.

Important additional information about respirator selection

NO open flames.

PREVENT DISPERSION OF DUST!

Use local exhaust or breathing protection.

Protective gloves. Protective clothing.

Wear face shield or eye protection in combination with breathing protection.

Do not eat, drink, or smoke during work.

Caprolactam is a clear to milky white-colored solution with a mild, disagreeable odor. Contact may cause slight irritation to skin, eyes, and mucous membranes. May be mildly toxic by ingestion. The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment. As a liquid it can easily penetrate the soil and contaminate groundwater and nearby streams. Used to make other chemicals.

Large Crystals; CBI; Large Crystals; Liquid; Liquid; Liquid; Other Solid

White, crystalline solid or flakes with an unpleasant odor; Note: Significant vapor concentrations would be expected only at elevated temperatures; [NIOSH]

WHITE HYGROSCOPIC CRYSTALS OR FLAKES.

Yellowish solid; Amine, spicy aroma

Clear to milky white-colored solution with a mild, disagreeable odor.

White, crystalline solid or flakes with an unpleasant odor. [Note: Significant vapor concentrations would be expected only at elevated temperatures.]

Hygroscopic leaflets from petroleum ether

White, crystalline solid or flakes ... [Note: Significant vapor concentrations would be expected only at elevated temperatures].

White flakes or fused

... Unpleasant odor ...

UNPLEASANT

512.4 °F at 760 mmHg (NTP, 1992)

BP: 180 °C @ 50 mm Hg

270 °C @760 [mm Hg]

156 °F (NTP, 1992)

257 °F (NTP, 1992)

125 °C o.c.

greater than or equal to 100 mg/mL at 68.9 °F (NTP, 1992)

Soluble in chlorinated solvents, petroleum distillate, and cyclohexene.

Freely sol in methanol, ethanol,tetrahydrofurfuryl alc; ether, dimethylformamide, sol in chlorinated hydrocarbons, cyclohexene, petroleum fractions

Soluble in benzene, ethanol, and chloroform

In water, 5.25X10+6 mg/l @ 25 °C.

Solubility in water: good

Soluble in water

Soluble (in ethanol)

1.02 at 170.6 °F (USCG, 1999) - Denser than water; will sink

Specific gravity: 1.02 at 75 °C/4 °C (liq)

Density: 1.05 @ 25 °C/4 °C /70% aq soln/

Relative density (water = 1): 1.02

1.02 @ 75°C in Liquid form

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

3.91 (air=1)

Relative vapor density (air = 1): 3.91

0.001 mmHg at 68 °F ; 3 mmHg at 212 °F (NTP, 1992)

0.0019 [mmHg]

Vapor pressure: 6 mm Hg @ 120 °C

1.9X10-3 mm Hg at 25 °C

Vapor pressure, Pa at 25 °C: 0.26

0.00000008 mmHg

Water soluble.

Amides and Imides

Polymerizable Compounds

Polymerizable

CAPROLACTAM is hygroscopic. This compound can react with strong oxidizing agents and strong bases. It can also react with chlorinated hydrocarbons and nitro compounds. A potentially explosive reaction occurs with acetic acid + dinitrogen trioxide. (NTP, 1992)

Strong oxidizers, (acetic acid + dinitrogen trioxide).

During preparation of the N-nitroso derivative from the lactam in acetic acid solution, the treatment with dinitrogen trioxide must be very effectively cooled to prevent explosive decomposition.

Strong oxidizers, (acetic acid + dinitrogen trioxide)

Caprolactam

Developmental

5 x 10 ^-1 mg/kg-day

Evaluation: No epidemiological data relevant to the carcinogenicity of caprolactam were available. There is evidence suggesting a lack of carcinogenicity of caprolactam in experimental animals. Overall evaluation: Caprolactam is probably not carcinogenic to humans (Group 4).

A5; Not suspected as a human carcinogen.

Group 3: Not classifiable as to its carcinogenicity to humans

Volume 39: (1986) Some Chemicals Used in Plastics and Elastomers

Volume Sup 7: Overall Evaluations of Carcinogenicity: An Updating of IARC Monographs Volumes 1 to 42, 1987; 440 pages; ISBN 92-832-1411-0 (out of print)

Volume 71: (1999) Re-evaluation of Some Organic Chemicals, Hydrazine and Hydrogen Peroxide (Part 1, Part 2, Part 3)

Moved to Group 3 following 2019 update to the IARC Monographs Preamble

TR-214: Carcinogenesis Bioassay of Caprolactam (CASRN 105-60-2) in F344 Rats and B6C3F1 Mice (Feed Study) (1982 )

06/27/80

No Evidence

Under the conditions of this bioassay, caprolactam was not carcinogenic for F344 rats or B6C3F1 mice.

The substance can be absorbed into the body by inhalation of its aerosol.

inhalation, ingestion, skin and/or eye contact

Cough. Abdominal cramps. Dizziness. Headache. Confusion.

Redness.

Redness. Pain.

Nausea. Vomiting. Abdominal pain. Diarrhoea.

irritation skin, eyes, respiratory system; epistaxis (nosebleed); dermatitis, skin sensitization; asthma; irritability, confusion, dizziness, headache; abdominal cramps, diarrhea, nausea, vomiting; liver, kidney injury

Eyes, skin, respiratory system, central nervous system, cardiovascular system, liver, kidneys

Neurotoxin - Other CNS neurotoxin

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.

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

ACGIH Carcinogen - Not Suspected.

IRIS Current

HEAST Current

LC50 (rat) = 300 mg/m3/2h

LD50 Mouse (male) oral 2.1 g/kg

LD50 Mouse (female) oral 2.5 g/kg

LD50 Rat (male) oral 1.6 g/kg

LD50 Rat (female) oral 1.2 g/kg

For more Non-Human Toxicity Values (Complete) data for CAPROLACTAM (12 total), please visit the HSDB record page.

Basic Treatment: Establish a patent airway. Suction if necessary. Encourage patient to take deep breaths. 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 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 ... . /Irritating materials/

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. Early intubation at the first sign of upper airway obstruction may be necessary. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias if necessary ... . Start an IV with D5W TKO /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 ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Irritating materials/

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/in. 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 ... . /Poisons 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 TKO /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 ... . /Poisons A and B/

... PERSONS SUBJECT TO PROLONGED EXPOSURE TO EPSILON-CAPROLACTAM SHOULD BE MEDICALLY EXAMINED, ESP THEIR RESP, CIRCULATORY & NERVOUS SYSTEMS /SRP: SKIN, GENITOURINARY TRACT/.

... WORKERS ... EXPOSED TO 61 MG/CU M ... & ... TO 16-17 MG/CU M OF /EPSILON-CAPROLACTAM/ ... COMPLAINED OF APPREHENSION & NERVOUS IRRITABILITY ... OTHER SYMPTOMS INCL BLEEDING FROM NOSE, DRYNESS OF NOSE, INFLAMMATION OF THROAT, PAINFUL LIPS, HEARTBURN, FLATULENCE & A BITTER TASTE IN MOUTH ... .

3.10e+04

4.00e+05

2.30e+00

9.60e+00

9.90e+03

5.00e+00

2.50e+00

5.00e-01

2.20e-03

Volatile

9.40e+04

1.20e+06

6.90e+00

2.90e+01

3.00e+04

This substance does enter the environment under normal use. Great care, however, should be taken to avoid any additional release, for example through inappropriate disposal.

Caprolactam's production and use in the manufacture of synthetic fibers of the polyamide type and as a solvent for high molecular weight polymers may result in its release to the environment through various waste streams. Caprolactam is produced in small quantities by some plants (i.e. sunflowers) as a secondary metabolite. If released to air, a vapor pressure of 1.9X10-3 mm Hg at 25 °C indicates caprolactam will exist solely in the vapor phase in the ambient atmosphere. Vapor-phase caprolactam 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 21 hours. If released to soil, caprolactam is expected to have high mobility based upon an estimated Koc of 57. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 5.4X10-11 atm-cu m/mole. Caprolactam biodegradation in soil has not been reported, but it has a relatively short half life (5 to 14 days) in both aerobic waste water treatment systems and other aquatic systems (lakes and rivers). This suggests that it will be degraded in most aerobic soils. Based on very slow hydrolysis rates of other aliphatic acid amides, hydrolysis would not be expected to be an important fate process. However, experiments conducted with sterile natural waters demonstrated that caprolactam is abiotically degraded. Since the product of this degradation was not identified, it is not known if the primary product of this abiotic degradation is aminocaproic acid, a product of the hydrolysis of caprolactam. If released into water, caprolactam is not expected to adsorb to suspended solids or to sediments in water based upon its estimated Koc of 57. Volatilization from water surfaces is not expected to be an important fate process based upon its estimated Henry's Law constant. An estimated BCF of 3.2 suggests the potential for bioconcentration in aquatic organisms is low. Occupational exposure to caprolactam may occur through inhalation and dermal contact with this compound at workplaces (carpet and polymer mills) where caprolactam is produced or used. (SRC)

Caprolactam was not thought to occur naturally in the environment(1), but it has been found as a secondary metabolite of the sunflower(2). It is thought to act as a growth regulator in these plants and inhibits the growth of other dicot seedlings (cress)(2).

Caprolactam's production and use in the manufacture of synthetic fibers of the polyamide type and as a solvent for high molecular weight polymers(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 57(SRC), determined from a structure estimation method(2), indicates that caprolactam is expected to have high mobility in soil(SRC). Volatilization of caprolactam from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 5.4X10-11 atm-cu m/mole from its vapor pressure, 1.9X10-3 mm Hg at 25 °C(5), and water solubility, 5.25X10+6 mg/l(6). Caprolactam is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.9X10-3 mm Hg at 25 °C(5). Caprolactam is degraded in aquatic environments with a half life of 5 to 15 days, and is expected to be degraded in aerobic soils in a similar timeframe(6).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 57(SRC), determined from an estimation method(2), indicates that caprolactam is not expected to adsorb to suspended solids or to sediments in water(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 5.4X10-11 atm-cu m/mole(SRC) calculated from its vapor pressure, 1.9X10-3 mm Hg at 25 °C(4), and water solubility, 5.25X10+6 mg/l(5). According to a classification scheme(6), an estimated BCF of 3.1(SRC), from an estimated log Kow of 0.66(7) suggests the potential for bioconcentration in aquatic organisms is low. Biodegradation in aquatic environments is expected to be extensive; complete degradation of 50-100 ug/ml caprolactam was observed in nutrient-amended or sediment-associated lake water in 21 days(8). Slightly less caprolactam was degraded (36-85%) after 21 days if higher concentrations (1000 to 2000 ug/ml) were used. However, in none of these control cases was any complete degradation (mineralization) of the caprolactam observed. Based on very slow hydrolysis rates of other aliphatic acid amides, hydrolysis is not expected to be an important fate process(5). Experiments conducted with sterile natural waters, however, demonstrated that caprolactam is abiotically degraded. It is not known whether or not the product of this abiotic degradation is the product of hydrolysis, aminocaproic acid(5).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), caprolactam, which has a vapor pressure of 1.9X10-3 mm Hg at 25 °C(4), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase caprolactam 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 21 hours(SRC), calculated from its rate constant of 18X10-12 cu cm/molecule-sec at 25 °C(3). Caprolactam does not absorb light in the environmental spectrum (>290 nm), indicating there is little potential for direct photolysis.

The activated sludge treatment of wastewater containing caprolactam from a Nylon 6 manufacturing plant was investigated by basic studies and by operating a full scale treatment plant. Activated sludges were obtained from municipal and industrial wastewater sources or were prepared by mixing caprolactam utilizing bacteria (Bacillus and Achromobacter) with municipal activated sludge. Bulking phenomena were observed in the acclimatization of ordinary activated sludges even when started from very low concentrations of caprolactam. The activated sludge synthesized from caprolactam utilizing bacteria showed better results with respect to sludge volume index, biochemical oxygen demand removal, and transparency of treated water. Wastewater from the Nylon 6 manufacturing plant, which contained caprolactam, was treated by this synthesized activated sludge in a bench scale apparatus consisting of a 4 cu m aeration basin and a 1.4 cu m sedimentation basin. The optimum biochemical oxygen demand loading was estimated to be 0.35 to 0.40 kg/kg of mixed liquor sludge solids/day. Production of excess activated sludge was 10% of the biochemical oxygen demand load. A wastewater treatment facility consisting of a 2500 cu m aeration basin and 1250 cu m sedimentation basin was constructed near the nylon 6 manufacturing plant to process 5000 cu m of wastewater (biochemical oxygen demand of 300 to 400 mg/l) per day. The treatment plant produces effluent with a biochemical oxygen demand below 10 mg/l.

Caprolactam (50 ug/ml) was biologically degraded in grab samples in 21 days(1). In sterilized stream and lake water samples 35-50% of the caprolactam underwent primary degradation(1) to aminocaproic acid, achieved by hydrolysis(2). In natural (not sterilized) waters, 75-100% of the chemical underwent primary degradation. Mineralization (complete degradation, as measured by %CO2 evolution) of caprolactam was not observed in any sterile water samples, but was observed in all non-sterile samples. After a 21 day incubation, grab samples at initial concentrations of 40.4 ug/ml were degraded as follows (as measured by %CO2 evolution): sterilized stream water: <5%; unsupplemented stream water: <5%; stream water plus sediment: 8%; stream water with yeast extract: 36%; sterilized lake water: <5%; unsupplemented lake water: 5%; lake water plus sediment: 10%; lake water with yeast extract: 50%. In grab samples of lake water amended with yeast extract at an initial concentration caprolactam at 50 ug/ml, when incubated at 10, 20, and 25 °C for 7 days, 17, 72, and 90% degradation was observed, respectively. After 21 days, nearly all the caprolactam at all temperatures was degraded. With lake water grab samples amended with yeast extract and a caprolactam concentration of 40.4 ppm, 8, 72, and 79% CO2 evolution was observed when incubated at 10, 20, and 25 °C, respectively. For a grab sample amended with caprolactam at concentrations of 100, 1000 and 2000 ug/ml, primary degradation of 100, 85 and 36%, respectively, was observed after 21 days. Grab samples amended with initial concentrations of 100, 1000, and 2000 ug/ml caprolactam showed 80, 32 and 8% CO2 evolution, respectively, in lake water supplemented with yeast extract(1).

BOD dilution water, 2 day 90% TOC removal, activated sludge inocula(1). BOD dilution water, initial concn corresponding to 200 mg/L C, 5 day 94.3% COD removal, acclimated activated sludge inocula (vigorous system)(2). OECD method, initial concn corresponding to 40 ppm C, 10 day acclimation, 19 day 93% COD removal(3). Zahn-Wellens, initial concn equivalent to 1000 mg/L COD, 6 days >90% degradation, 3.5 day lag period, non-adapted acclimated sludge inocula(4). Zahn-Wellens, 5 day 88% COD removal; Sapromat respirometer, 5 day 82% COD removal; Closed bottle test, 5 day 10% Theoretical Biochemical Oxygen Demand (5). A proposed mechanism for metabolism: caprolactam to epsilon-aminocaproic acid adipic semialdehyde to adipic acid(6).

AEROBIC: Several bacterial strains can degrade caprolactam(1) and it is degraded in activated sludge treatment plants and natural waters(1). Caprolactam, present at 100 mg/l, reached 100% of its theoretical degradation in 1 week using a carbon-supplemented lake water as the environmental medium, incubated at 20 °C. At higher concentrations (1000-2000 mg/l), caprolactam was degraded (80 and 60%, respectively) within three weeks in carbon supplemented lake water(1). These test levels are higher than predicted environmental spill concentrations of >=50 mg/l, or of continuous release concentrations of <= 10 mg/l(1). Caprolactam, present at 100 mg/l, reached 82% of its theoretical BOD in 2 weeks using an activated sludge inoculum at 30 mg/l and the Japanese MITI test(2).

The rate constant for the vapor-phase reaction of caprolactam with photochemically-produced hydroxyl radicals has been estimated nas 1.8X10+13 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 21 hrs(SRC) at an atmospheric concn of 5X10+5 hydroxyl radicals per cu cm(1). Caprolactam is reported to have an atmospheric lifetime of less than one day, based on the lack of reaction product data(2). It has been reported that aliphatic acid amides are resistant to hydrolysis(3). Conversely, it has also been reported that amides undergo chemical hydrolysis(4). Based on experimental evidence(5), caprolactam underwent primary degradation in sterile water, which may have been due to chemical hydrolysis, however, no identification of the reaction product was performed. Caprolactam is not expected to photolyze due to the lack of absorption in the environmental UV spectrum (>290 nm).

An estimated BCF of 3.2 was calculated for caprolactam(SRC), using an estimated log Kow of 0.66(1,SRC) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low.

Using a structure estimation method based on molecular connectivity indices(1), the Koc for caprolactam is estimated to be 57(SRC). According to a classification scheme(2), this estimated Koc value suggests that caprolactam is expected to have high mobility in soil.

The Henry's Law constant for caprolactam is estimated as 5.4X10-11 atm-cu m/mole(SRC), calculated from its vapor pressure, 1.9X10-3 mm Hg at 25 °C(1), and water solubility, 5.25X10+6 mg/l(2). This Henry's Law constant indicates that caprolactam is expected to be essentially nonvolatile from water surfaces(3). Caprolactam's estimated Henry's Law constant indicates that volatilization from moist soil surfaces will not occur(SRC). Caprolactam is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

CAPROLACTAM ... REPORTED TO BE PRESENT ... IN WASTE WATERS FROM NYLON 6 PLANTS IN JAPAN & RUSSIA ... DETECTED IN (1) FINISHED DRINKING-WATER IN US...(2) EFFLUENT WATER FROM LANDFILL LEACHATE IN DELAWARE ... (3) FINAL EFFLUENT WASTE-WATER FROM DYE MFR PLANT, @ LEVELS OF 36-150 UG/L.

GROUND WATER: June 1975 qualitatively identified in well water(1). April 1974 qualitatively identified in landfill leachate from sites in Dover, DE and Newcastle County, DE(1). A series of montoring wells installed at the Wilder's Grove landfill, Raleigh, NC showed concns of caprolactam at 995, 95, <5.0, 133 ug/l (outflow from sedimentation basin) and 78, 88, <5.0, and <5.0 ug/l, inflow from surrounding waste deposit sites to sedimentation basin(2).

DRINKING WATER: July 1975 and Jan 1976 qualitatively identified in drinking water in the US(1). Caprolactam was qualitatively identified in drinking water in Germany(2).

SURFACE WATER: Stream water samples collected Dec 1983, downstream from tire fire which broke out in Winchester, VA during Oct 1983, 9700 ug/l - 0.67 km downstream, 250 ug/l - 1.1 km downstream, and 44 ug/l - 9 km downstream(1). Caprolactam was identified at Lobith, Germany on the Rhine River at a concn of 0.88 ug/l(2).

July 1976, dye manufacturing plant in MA, concn range 36-150 ug/L(1). Qualitatively identified in water samples taken from advance waste treatment plants in Lake Tahoe, CA Oct 1974 and Washington D.C. Sept 1974(2). Present in trace amounts in the waste waters from nylon 6 manufacturing plants in Japan and Russia(3).

URBAN/SUBURBAN: A survey of ambient atmospheric sampling data in populated areas of the United States was conducted for the compounds in the 189 Hazardous Air Pollutant List (HAP), one of which is caprolactam(1). No ambient measurement data for caprolactam was located(1).

Residual monomers and oligomers were determined in nylon food packing following oven cooking with food oil(1). The average content of caprolactam in an oven roasting bag is 0.438 mg/g; the average amount of caprolactam migrating to oil after heating was 0.98 ug/g(1).

VALUES OF 20-40 MG/CU M ... IN POLYMERISATION SHOP & IN WEAVING WORKSHOPS. FOR 8 HR WORKING PERIOD THIS REPRESENTS TOTAL AMT OF LACTAM BREATHED EQUAL TO AVG VALUE OF 0.1-0.2 G.

NIOSH has statistically estimated that 8661 workers (4209 of these are female) workers are potentially exposed to caprolactam in the US(1). Occupational exposure to caprolactam may occur through inhalation and dermal contact with this compound at workplaces where caprolactam is produced or used(SRC). The general population may be exposed to caprolactam via inhalation of ambient air, especially around new carpet installations(2,3).

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

Controlled incineration (oxides of nitrogen are removed from the effluent gas by scrubbers and/or thermal devices). Also caprolactam may be recovered from caprolactam still bottoms or nylon waste. Recommendable method: Incineration.

The following wastewater treatment technologies have been investigated for caprolactam: biological treatment.

Symbol: Xn; R: 20/22-36/37/38; S: (2)