1-Naphthaleneacetic Acid

This chemical does not meet GHS hazard criteria for 0.9% (1 of 112) of reports.

H302 (97.3%): Harmful if swallowed [Warning Acute toxicity, oral]

H315 (73.2%): Causes skin irritation [Warning Skin corrosion/irritation]

H318 (77.7%): Causes serious eye damage [Danger Serious eye damage/eye irritation]

H319 (13.4%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H335 (72.3%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

H412 (67%): Harmful to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

P261, P264, P264+P265, P270, P271, P273, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, P305+P354+P338, P317, P319, P321, P330, P332+P317, P337+P317, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 112 reports by companies from 25 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 112 reports by companies.

There are 24 notifications provided by 111 of 112 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.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

SRP: 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.

Do not get on skin or in eyes. ... Do not spray in strong sunlight; preferably spray in late afternoon, evening, or at dusk.

...Store in cool, dry, dark place.

Tolerances are established for residues of the plant growth regulator 1-naphthaleneacetic acid in or on the following raw agricultural commodities: apple, 1 ppm; cherry, sweet, 0.1 ppm; olive, 0.1ppm (negligible residues); orange, sweet, 0.1 ppm; pear, 1 ppm; pineaple (from the application of the sodium salt to the growing crop), 0.05 ppm; quince, 1 ppm; and tangerine, 0.1 ppm.

Wear rubber gloves.

White odorless solid; [Hawley] White or beige powder; [MSDSonline]

Needles from water

White crystals

Colorless crystals

Odorless

Decomposes

134.5-135.5 °C

Melting point of 125-128 °C /Technical grade/

134.5 - 135.5 °C

Slightly soluble in ethanol, trifluoroacetic acid; soluble in benzene and acetic acid; very soluble in ethyl ether, acetone, and chloroform.

10.6 mg/l in carbon tetrachloride @ 26 °C; 55 mg/l in xylene at 26 °C

About 30 parts in alcohol

Very sol in isopropanol

In water, 420 mg/l @ 20 °C

0.42 mg/mL at 20 °C

0.0000159 [mmHg]

log Kow = 2.24

/Aqueous solution of sodium salt is/ very unstable to UV and sunlight irradiation. /Aqueous solution of sodium salt/

Stable /during storage/.

Some evidence of ultraviolet degradation.

When heated to decomposition it emits acrid smoke and irritating fumes.

4.23 (at 25 °C)

pKa = 4.23

Alkali metal and amine salts are readily soluble in water.

13C nuclear magnetic resonance spectrum

Chemical shift

Fusion temperature

Melting temperature

Phase transition

Spin-spin coupling constant

Transition enthalpy

Pharmaceuticals -> Listed in ZINC15

Potential endocrine disrupting compound

Attractants

Active substance -> EU Pesticides database: Approved

Pesticides -> Plant Growth Regulators

Environmental transformation -> Pesticides (parent, predecessor)

Environmental transformation -> Pesticide transformation products (metabolite, successor)

Solutions of the heavy-metal salts of other acids form sparingly-soluble salts of 1-naphthylacetic acid.

Chemical: POTASSIUM NAPHTHALENEACETATE

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.

Napthalene Acetates

General Population

Human Health Benchmarks for Pesticides - 2021 Update

LC50 (rat) > 207,000 mg/m3

LD50 Mouse ip 609 mg/kg

LD50 Mouse oral 743 mg/kg

LD50 Rat ip 100 mg/kg

LD50 Rat oral 1000 mg/kg

LD50 Rabbit percutaneous greater than 5000 mg/kg

The inhibition of wheat coleoptile extension growth by concn of NC 9634 at about 260 muM was completely overcome by 50 uM naphthaleneacetic acid (NAA). Extension growth of intact apple shoots was inhibited by NAA, which was lethal at about 6.25X10-4 M. NC 9634 applied in combination with NAA reduced this growth inhibiting effect and prevented death of shoots sprayed with high auxin concn.

Basic treatment: Establish a patent airway. 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 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. Administer activated charcoal ... . /Naphthalene and Related Compounds/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious. Start an IV with lactated Ringer's. Adequate hydration must be maintained to prevent renal failure secondary to myoglobinuria unless signs of cerebral or pulmonary edema are present. For hypotension with signs of hypovolemia, administer fluid cautiously. 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. ... . Treat seizures with diazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Naphthalene and related compounds/

Maintain an open air way and assist ventilation if necessary. Treat coma and seizures if they occur. Treat hemolysis and resulting hemoglobinuria if they occur by intravenous hydration and urinary alkalinization. There is no specific antidote. Administer activated charcoal if available. Do not induce vomiting, because of the risk of lethargy and seizures. Do not administer milk, fats or oils, which may enhance absorption /Naphthalene/

NAPHTHALENE toxicosis caused by vapor inhalation can usually be managed simply by removing the individual to fresh air. Skin contamination should be removed promptly by washing with soap and water. Eye contamination should be removed by flushing with copious amounts of clear water. Irritation may be severe, and if it persists, should receive medical attention. SRP: /It may be helpful to empty stomach and administer dose of activated charcoal/ Examine the plasma for evidence of hemolysis: a reddish-brown tinge. Examine the blood smear for "ghosts" and Heinz bodies. If /hemolysis is/ present, monitor red blood cell count and hematocrit for anemia, urine for protein, and cells. Measure direct- and indirect-reacting bilirubin in the plasma. Monitor fluid balance and blood electrolytes. If possible, monitor urinary excretion of naphthol to assess severity of poisoning and clinical progress. If hemolysis is clinically significnt, administer intravenous fluids to accelerate urinary excretion of the naphthol metabolite and protect the kidney from products of hemolysis. Use Ringer's-lactate or sodium bicarbonate to keep urine pH above 7.5. Consider use of mannitol, or furosemide, to promote diuresis. If urine flow declines, intravenous infusions must be carefully monitored to avoid fluid overload. Institute hemodialysis. Consider charcoal hemoperfusion in tandem to extract naphthalene and end-products. If anemia is severe, blood transfusions may be needed. Hydrocortisone may be of some benefit if significant hemolysis is present. /Fumigant poisoning/

/HUMAN EXPOSURE STUDIES/ Dusts may cause nasal irritation.

/HUMAN EXPOSURE STUDIES/ A skin, mucous membrane, and severe eye irritant.

/LABORATORY ANIMALS: Acute Exposure/ In animals it produces gastroenteritis and central nervous depression. Slight to moderate irritation of rabbit skin after prolonged contact... .

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ Administration of 0, 200, 1,000 and 5,000 ppm in diets to male and female rats for 90 days reduced growth and food intake in males at 5,000 ppm. Reduction in leukocyte count at 1,000 and 5,000 ppm level was mainly due to reduction in neutrophils.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ Groups of 20 or 30 (control and high dose) Sprague-Dawley rats / sex were fed diets containing naphthalene acetic acid (no lot #, purity not stated) for 90 days that produced exposures of approximately 0, 50, 150, or 500 mg/kg/day (measured values were 95 to 100% of nominal values). Ten high-dose and 10 control rats/sex were sacrificed after 29/30 days and the remaining rats sacrificed at 90 days. There were no treatment- related effects on behavior, clinical signs, food consumption, urinalysis, gross necropsy, or histopathology. Treatment-related effects included decreased body weight gain, and increased serum alkaline phosphatase levels in both sexes at 500 mg/kg/day; decreased hematocrit, hemoglobin, red blood count in males and increased female liver weights at 500 mg/kg/day (NOEL = 150 mg/kg/day).

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ Groups of 4 beagle dogs/sex received oral doses (in gelatine capsules) of 1-naphthaleneacetic acid sodium salt (batch lot # 214001, 96.44% purity) at 0, 25, 150, or 450 mg/kg/day for 13 weeks. Treatment-related effects seen in both sexes at 450 mg/kg/day included: increased emesis and salivation; decreased food intake and body weight gain (13-wk body weights were 73% (M) and 75% (F) of controls); lowered red blood cell count, hematocrit, and hemoglobin levels; increased serum levels of aspartate aminotransferase, alanine aminotransferase, and total bilirubin; and increased relative liver weights. Gastrointestinal lesions and bone marrow hypocellularity were seen in both sexes at 150 and 450 mg/kg/day. Small prostate (4/4), testes (3/4), and epididymae (3/4), atrophied testes (4/4), and hypo/aspermia (4/4) were seen in males at 450 mg/kg/day (NOEL = 25 mg/kg/day, /maximum tolerated dose/ = 450 mg/kg/day). /1-Naphthaleneacetic acid sodium salt/

For more Non-Human Toxicity Excerpts (Complete) data for 1-NAPHTHALENEACETIC ACID (14 total), please visit the HSDB record page.

LC50 Mallard duck (8 days) >10,000 mg/kg

LC50 Bobwhite quail (8 days) >10,000 mg/kg

LC50 Rainbow trout 57 mg active ingredient /L / 96 hr /Conditions of bioassay not specified/

LC50 Bluegill sunfish 82 mg active ingredient/L/96 hr /Conditions of bioassay not specified/

/OTHER TERRESTRIAL SPECIES/ Nontoxic to bees

1-Naphthaleneacetic acid's production may result in its release to the environment through various waste streams; it's use as a plant growth regulator will result in its direct release to the environment. If released to air, an estimated vapor pressure of 1.6X10-5 mm Hg at 25 °C indicates 1-naphthaleneacetic acid will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 1-naphthaleneacetic acid 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 10 hrs. Particulate-phase 1-naphthaleneacetic acid will be removed from the atmosphere by wet and dry deposition. Photolysis may be an important environmental fate process in the atmosphere based upon aqueous photolysis data. If released to soil, 1-naphthaleneacetic acid is expected to have moderate mobility based upon an estimated Koc of 390. The pKa of 1-naphthaleneacetic acid is 4.23, indicating that this compound will primarily exist in the dissociated form in the environment and anions generally do not adsorb more strongly to organic carbon and clay than their neutral counterparts. Volatilization from moist soil surfaces is not expected to be an important fate process because anions do not volatilize. 1-Naphthaleneacetic acid has a reported half-life in soil of 10 days, attributed to microbial degradation. If released into water, 1-naphthaleneacetic acid is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. A pKa of 4.23 indicates 1-naphthaleneacetic acid will exist almost entirely in the ionized form at pH values of 5 to 9 and anions do not volatilize. Biodegradation is not expected to be a fast environmental fate process in water based upon a 0% theoretical BOD using activated sludge and the MITI test. A BCF range of 0.5-4.2 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 1-naphthaleneacetic acid may occur through inhalation and dermal contact with this compound at workplaces where 1-naphthaleneacetic acid is produced or used. Monitoring data indicate that the general population may be exposed to 1-naphthaleneacetic acid via inhalation of ingestion of contaminated fruits. (SRC)

1-Naphthaleneacetic acid's production may result in its release to the environment through various waste streams; it's use as a plant growth regulator(1) will result in its direct release to the environment(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 390(SRC), determined from a log Kow of 2.24(2) and a regression-derived equation(3), indicates that 1-naphthaleneacetic acid is expected to have moderate mobility in soil(SRC). The pKa of 1-naphthaleneacetic acid is 4.23(4), indicating that this compound will exist as an anion in the environment and anions typically have greater mobility in soils than do neutral species(5). Volatilization of 1-naphthaleneacetic acid from moist soil surfaces is not expected to be an important fate process(SRC) because anions do not volatilize. 1-Naphthaleneacetic acid is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.6X10-5 mm Hg(SRC), determined from a fragment constant method(6). 1-Naphthaleneacetic acid has a reported half-life in soil of 10 days, attributed to microbial degradation(7).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 390(SRC), determined from a log Kow of 2.24(2) and a regression-derived equation(3), indicates that 1-naphthaleneacetic acid is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected based upon a pKa of 1-naphthaleneacetic acid of 4.23(4), indicating that this compound will primarily exist in the dissociated form in the environment and anions generally do not adsorb more strongly to organic carbon and clay than their neutral counterparts(5). According to a classification scheme(6), a BCF range of 0.5-4.2(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Biodegradation is not expected to be a fast environmental fate process in water based upon a 0% theoretical BOD using activated sludge and the MITI test(7). Photolysis may be an important environmental fate process as indicated by the detection of photolysis products 1-naphthoic and phthalic acids following exposure of an aqueous solution of 1-naphthaleneacetic acid to sunlight(8,9).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 1-naphthaleneacetic acid, which has an estimated vapor pressure of 1.6X10-5 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 1-naphthaleneacetic acid 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 10 hrs(SRC), calculated from its rate constant of 3.7X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase 1-naphthaleneacetic acid may be removed from the air by wet and dry deposition(SRC). Photolysis may be an important environmental fate process in the atmosphere as indicated by the detection of photolysis products 1-naphthoic and phthalic acids during analysis of a sunlight exposed aqueous solution of 1-naphthaleneacetic acid(4,5).

AEROBIC: 1-Naphthaleneacetic acid, present at 30 mg/l, reached 0% of its theoretical BOD in 2 weeks using an activated sludge inoculum at 100 mg/l and the Japanese MITI test(1). 1-Naphthaleneacetic acid has a reported half-life in soil of 10 days, attributed to microbial degradation(2).

EXPOSURE OF NAPHTHALENEACETIC ACID TO ULTRAVIOLET LIGHT & SUNLIGHT PRODUCED 1-HYDROXMETHYL NAPHTHALENE, 1-NAPHTHALDEHYDE, NAPHTHALENE-1-CARBOXYLIC ACID & 1-METHYL NAPHTHALENE UNDER AEROBIC CONDITIONS. ANAEROBICALLY, ONLY THE 1-METHYL ANALOG WAS OBSERVED. PHTHALIC ACID HAS ALSO BEEN OBSERVED.

A METABOLIC PRODUCT OF NAPHTHALENEACETIC ACID FROM WHEAT COLEOPTILES WAS IDENTIFIED AS THE 5-HYDROXY ANALOG. ON THE /APPLE/ LEAF, UV RADIATION DEGRADED NAA WITH LOSS OF THE CARBOXYL GROUP.

The rate constant for the vapor-phase reaction of 1-naphthaleneacetic acid with photochemically-produced hydroxyl radicals has been estimated as 3.7X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 10 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 1-Naphthaleneacetic acid is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(2). Photolysis in air and water were identified as the major degradation process for carboxylic acid plant growth regulators(3). 1-Naphthoic and phthalic acids were identified as the photolysis products of 1-naphthaleneacetic acid in sunlight exposed aqueous solution(4,5).

BCFs of 0.15-0.59 and <1.7-4.2 were measured in carp (Cyprinus carpio) for 1-naphthaleneacetic acid at test chemical concns of 0.5 and 0.05 mg/l, respectively(1). According to a classification scheme(2), these BCFs suggest the potential for bioconcentration in aquatic organisms is low(SRC).

The Koc of 1-naphthaleneacetic acid is estimated as 390(SRC), using a log Kow of 2.24(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that 1-naphthaleneacetic acid is expected to have moderate mobility in soil. The pKa of 1-naphthaleneacetic acid is 4.23(4), indicating that this compound will primarily exist in the dissociated form in the environment and anions generally have greater mobility than their neutral counterparts(5).

The pKa of 1-naphthaleneacetic acid is 4.23(1), which indicates this compound will exist as an anion in the environment. Volatilization from water and moist soil surfaces will not occur since anions do not volatilize. Volatilization from dry soil is not expected(SRC), based on its estimated vapor pressure of 1.6X10-9 mm Hg at 25 °C determined from a fragment constant method(2).

LC50 Mallard duck (8 days) >10,000 mg/kg

LC50 Bobwhite quail (8 days) >10,000 mg/kg

LC50 Rainbow trout 57 mg active ingredient /L / 96 hr /Conditions of bioassay not specified/

LC50 Bluegill sunfish 82 mg active ingredient/L/96 hr /Conditions of bioassay not specified/

/OTHER TERRESTRIAL SPECIES/ Nontoxic to bees

1-Naphthaleneacetic acid's production may result in its release to the environment through various waste streams; it's use as a plant growth regulator will result in its direct release to the environment. If released to air, an estimated vapor pressure of 1.6X10-5 mm Hg at 25 °C indicates 1-naphthaleneacetic acid will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 1-naphthaleneacetic acid 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 10 hrs. Particulate-phase 1-naphthaleneacetic acid will be removed from the atmosphere by wet and dry deposition. Photolysis may be an important environmental fate process in the atmosphere based upon aqueous photolysis data. If released to soil, 1-naphthaleneacetic acid is expected to have moderate mobility based upon an estimated Koc of 390. The pKa of 1-naphthaleneacetic acid is 4.23, indicating that this compound will primarily exist in the dissociated form in the environment and anions generally do not adsorb more strongly to organic carbon and clay than their neutral counterparts. Volatilization from moist soil surfaces is not expected to be an important fate process because anions do not volatilize. 1-Naphthaleneacetic acid has a reported half-life in soil of 10 days, attributed to microbial degradation. If released into water, 1-naphthaleneacetic acid is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. A pKa of 4.23 indicates 1-naphthaleneacetic acid will exist almost entirely in the ionized form at pH values of 5 to 9 and anions do not volatilize. Biodegradation is not expected to be a fast environmental fate process in water based upon a 0% theoretical BOD using activated sludge and the MITI test. A BCF range of 0.5-4.2 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 1-naphthaleneacetic acid may occur through inhalation and dermal contact with this compound at workplaces where 1-naphthaleneacetic acid is produced or used. Monitoring data indicate that the general population may be exposed to 1-naphthaleneacetic acid via inhalation of ingestion of contaminated fruits. (SRC)

1-Naphthaleneacetic acid's production may result in its release to the environment through various waste streams; it's use as a plant growth regulator(1) will result in its direct release to the environment(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 390(SRC), determined from a log Kow of 2.24(2) and a regression-derived equation(3), indicates that 1-naphthaleneacetic acid is expected to have moderate mobility in soil(SRC). The pKa of 1-naphthaleneacetic acid is 4.23(4), indicating that this compound will exist as an anion in the environment and anions typically have greater mobility in soils than do neutral species(5). Volatilization of 1-naphthaleneacetic acid from moist soil surfaces is not expected to be an important fate process(SRC) because anions do not volatilize. 1-Naphthaleneacetic acid is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.6X10-5 mm Hg(SRC), determined from a fragment constant method(6). 1-Naphthaleneacetic acid has a reported half-life in soil of 10 days, attributed to microbial degradation(7).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 390(SRC), determined from a log Kow of 2.24(2) and a regression-derived equation(3), indicates that 1-naphthaleneacetic acid is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected based upon a pKa of 1-naphthaleneacetic acid of 4.23(4), indicating that this compound will primarily exist in the dissociated form in the environment and anions generally do not adsorb more strongly to organic carbon and clay than their neutral counterparts(5). According to a classification scheme(6), a BCF range of 0.5-4.2(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Biodegradation is not expected to be a fast environmental fate process in water based upon a 0% theoretical BOD using activated sludge and the MITI test(7). Photolysis may be an important environmental fate process as indicated by the detection of photolysis products 1-naphthoic and phthalic acids following exposure of an aqueous solution of 1-naphthaleneacetic acid to sunlight(8,9).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 1-naphthaleneacetic acid, which has an estimated vapor pressure of 1.6X10-5 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 1-naphthaleneacetic acid 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 10 hrs(SRC), calculated from its rate constant of 3.7X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase 1-naphthaleneacetic acid may be removed from the air by wet and dry deposition(SRC). Photolysis may be an important environmental fate process in the atmosphere as indicated by the detection of photolysis products 1-naphthoic and phthalic acids during analysis of a sunlight exposed aqueous solution of 1-naphthaleneacetic acid(4,5).

AEROBIC: 1-Naphthaleneacetic acid, present at 30 mg/l, reached 0% of its theoretical BOD in 2 weeks using an activated sludge inoculum at 100 mg/l and the Japanese MITI test(1). 1-Naphthaleneacetic acid has a reported half-life in soil of 10 days, attributed to microbial degradation(2).

EXPOSURE OF NAPHTHALENEACETIC ACID TO ULTRAVIOLET LIGHT & SUNLIGHT PRODUCED 1-HYDROXMETHYL NAPHTHALENE, 1-NAPHTHALDEHYDE, NAPHTHALENE-1-CARBOXYLIC ACID & 1-METHYL NAPHTHALENE UNDER AEROBIC CONDITIONS. ANAEROBICALLY, ONLY THE 1-METHYL ANALOG WAS OBSERVED. PHTHALIC ACID HAS ALSO BEEN OBSERVED.

A METABOLIC PRODUCT OF NAPHTHALENEACETIC ACID FROM WHEAT COLEOPTILES WAS IDENTIFIED AS THE 5-HYDROXY ANALOG. ON THE /APPLE/ LEAF, UV RADIATION DEGRADED NAA WITH LOSS OF THE CARBOXYL GROUP.

The rate constant for the vapor-phase reaction of 1-naphthaleneacetic acid with photochemically-produced hydroxyl radicals has been estimated as 3.7X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 10 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 1-Naphthaleneacetic acid is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(2). Photolysis in air and water were identified as the major degradation process for carboxylic acid plant growth regulators(3). 1-Naphthoic and phthalic acids were identified as the photolysis products of 1-naphthaleneacetic acid in sunlight exposed aqueous solution(4,5).

BCFs of 0.15-0.59 and <1.7-4.2 were measured in carp (Cyprinus carpio) for 1-naphthaleneacetic acid at test chemical concns of 0.5 and 0.05 mg/l, respectively(1). According to a classification scheme(2), these BCFs suggest the potential for bioconcentration in aquatic organisms is low(SRC).

The Koc of 1-naphthaleneacetic acid is estimated as 390(SRC), using a log Kow of 2.24(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that 1-naphthaleneacetic acid is expected to have moderate mobility in soil. The pKa of 1-naphthaleneacetic acid is 4.23(4), indicating that this compound will primarily exist in the dissociated form in the environment and anions generally have greater mobility than their neutral counterparts(5).

The pKa of 1-naphthaleneacetic acid is 4.23(1), which indicates this compound will exist as an anion in the environment. Volatilization from water and moist soil surfaces will not occur since anions do not volatilize. Volatilization from dry soil is not expected(SRC), based on its estimated vapor pressure of 1.6X10-9 mm Hg at 25 °C determined from a fragment constant method(2).

1-Naphthaleneacetic acid was detected in 1 of 2,363 domestic apple samples collected between October 1, 1985 and September 30, 1991, analyzed as part of the EPA Total Diet Study(1). The maximum residue measured was 0.02 ppm(1).

1-Naphthaleneacetic acid was shown to be readily absorbed in tomato fruit cuticles(1). Lipophilic in nature, 1-naphthaleneacetic acid applied as a spray concn of 1 g/l to maize, rape, strawberry, and sugar beet resulted in plant uptake rates of 26, 98, 96, and 61% of amount applied, respectively, after 24 hrs; plants characterized by waxy leaves exhibited more rapid uptake(2). Use of a surfactant (NP8, nonylphenol) decreased the rate of absorption to 17, 15, 35, and 13%, respectively(2).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 3,732 workers (574 of these are female) are potentially exposed to 1-naphthaleneacetic acid in the US(1). The NOES Survey does not include farm workers. Occupational exposure to 1-naphthaleneacetic acid may occur through inhalation and dermal contact with this compound at workplaces where 1-naphthaleneacetic acid is produced or used(SRC). Monitoring data indicate that the general population may be exposed to 1-naphthaleneacetic acid via inhalation of ingestion of contaminated fruits(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.