2-Chlorophenoxyacetic acid

log Kow = 1.86

2.02

Warning

H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]

P261, P264, P264+P265, P270, P271, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, 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 46 reports by companies from 6 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

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.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 18(SRC), determined from a structure estimation method(2), indicates that 2-chlorophenoxyacetic acid is expected to have very high mobility in soil(SRC). Furthermore, the pKa of 2-chlorophenoxyacetic acid is 3.05(3), indicating it will exist primarily as an anion under environmental conditions and anions generally possess greater mobility in soils than neutral compounds(4). Volatilization from moist soil surfaces will not be an important environmental fate process since anions do not volatilize(SRC). 2-Chlorophenoxyacetic acid is not expected to volatilize from dry soil surfaces(SRC), based upon an estimated vapor pressure of 3.2X10-4 mm Hg at 25 °C(SRC), determined from a fragment constant method(5). The time required for 80% degradation of 2-chlorophenoxyacetic acid in soil was >360 days in fresh soil and 31.8 days in a soil adapted to MPCA(6).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 18(SRC), determined from a structure estimation method(2), indicates that 2-chlorophenoxyacetic acid is not expected to adsorb to suspended solids and sediment(SRC). The pKa of 2-chlorophenoxyacetic acid is 3.05(3), indicating it will exist primarily as an anion under environmental conditions; therefore volatilization from water surfaces is not an important environmental fate process since anions do not volatilize(SRC). According to a classification scheme(4), an estimated BCF of 3(SRC), from a log Kow of 1.86(5) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Biodegradation studies using soil(7,8), suggest that biodegradation of 2-chlorophenoxyacetic acid occurs slowly in the environment. 2-Chlorophenoxyacetic acid may be susceptible to photolysis in sunlit surface waters since the structural isomer, 4-chlorophenoxyacetic acid, was degraded 30% in 24 hours when exposed to sunlight(9).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2-chlorophenoxyacetic acid, which has an estimated vapor pressure of 3.2X10-4 mm Hg at 25 °C(2), is expected to exist solely in the vapor-phase in the ambient atmosphere. Vapor-phase 2-chlorophenoxyacetic 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 35 hours(SRC), calculated from its rate constant of 1.1X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). A structural isomer, 4-chlorophenoxyacetic acid was degraded 30% upon exposure to natural sunlight over the course of 24 hours(4), suggesting photodegradation may be an important environmental fate process for 2-chlorophenoxyacetic acid(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc for 2-chlorophenoxyacetic acid can be estimated to be 18(SRC). According to a classification scheme(2), this estimated Koc value suggests that 2-chlorophenoxyacetic acid is expected to have very high mobility in soil(SRC). In addition, the pKa of 2-chlorophenoxyacetic acid is 3.05(3), indicating that this compound will primarily exist as an anion in the environment, and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4).

2-Chlorophenoxyacetic acid's production and use as a chemical reagent(1), may result in its release to the environment through various waste streams(SRC). 2-Chlorophenoxyacetic acid is an impurity in the herbicide 4-chloro-2-methylphenoxy acetic acid (MCPA)(2), and MCPA's use will result in the release of 2-chlorophenoxyacetic acid to the environment(SRC).

AEROBIC: 2-Chlorophenoxyacetic acid was completely degraded in 47, 124, and 205 days in a Honeoye silt loam, Mardin silt loam, and Dunkirk silt loam, respectively(1). The time required for 80% degradation of 2-chlorophenoxyacetic acid in soil was >360 days in fresh soil and 31.8 days in a soil adapted to MPCA(2).

An estimated BCF of 3 was calculated for 2-chlorophenoxyacetic acid (SRC), using a log Kow of 1.86(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).

The pKa of 2-chlorophenoxyacetic acid is 3.05(1), indicating that this compound will exist primarily as an anion under environmental conditions. Volatilization will not occur from water and moist soils since anions do not volatilize(SRC). 2-Chlorophenoxyacetic acid is not expected to volatilize from dry soil surfaces(SRC), based upon an estimated vapor pressure of 3.2X10-4 mm Hg at 25 °C(SRC), determined from a fragment constant estimation method(2).

The rate constant for the vapor phase reaction of 2-chlorophenoxyacetic acid with photochemically produced hydroxyl radicals has been estimated to be 1.1X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 35 hours at an atmospheric concn of 5X10+5 hydroxyl radicals per cu cm(1). A structural isomer, 4-chlorophenoxyacetic acid was stable to hydrolysis (half-life > 30 days) at pH 5, 7, and 9 and was degraded 30% upon exposure to natural sunlight over the course of 24 hours(2). These data suggest that 2-chlorophenoxyacetic acid is stable to hydrolysis, but may be susceptible to photolysis in the environment(SRC).

Occupational exposure to 2-chlorophenoxyacetic acid may occur through inhalation and dermal contact with this compound at workplaces where 2-chlorophenoxyacetic acid is produced or used. As this compound is a minor impurity in the herbicide, 4-chloro-2-methylphenoxy acetic acid (MCPA), dermal and inhalation exposure may also arise resulting from the use and production of the herbicide MCPA. (SRC)

2-Chlorophenoxyacetic acid's production and use as a chemical reagent, may result in its release to the environment through various waste streams. 2-Chlorophenoxyacetic acid is an impurity in the herbicide 4-chloro-2-methylphenoxy acetic acid (MCPA), and MCPA's use will result in the release of 2-chlorophenoxyacetic acid to the environment. If released to air, an estimated vapor pressure of 3.2X10-4 mm Hg at 25 °C indicates 2-chlorophenoxyacetic acid will exist solely as a vapor in the ambient atmosphere. Vapor-phase 2-chlorophenoxyacetic 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 35 hours. A structural isomer, 4-chlorophenoxyacetic acid was degraded 30% upon exposure to natural sunlight over the course of 24 hours, suggesting photodegradation of 2-chlorophenoxyacetic acid may be an important environmental fate process. If released to soil, 2-chlorophenoxyacetic acid is expected to have very high mobility based upon an estimated Koc of 18. The pKa of 2-chlorophenoxyacetic acid is 3.05, which indicates it will exist primarily as an anion under environmental conditions. Volatilization from moist soil surfaces will not be an important fate process because anions do not volatilize. 2-Chlorophenoxyacetic acid is not expected to volatilize from dry soil surfaces based upon its estimated vapor pressure. The time required for 80% degradation of 2-chlorophenoxyacetic acid in soil was >360 days in fresh soil and 31.8 days in a soil adapted to MPCA. If released into water, 2-chlorophenoxyacetic acid is not expected to adsorb to suspended solids and sediment based upon the estimated Koc value. Volatilization will not be an important fate process in water since anions do not volatilize. 2-Chlorophenoxyacetic acid is resistant to aqueous environmental hydrolysis; however, photolysis in sunlit surface waters may be an important fate process. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Occupational exposure to 2-chlorophenoxyacetic acid may occur through inhalation and dermal contact with this compound at workplaces where 2-chlorophenoxyacetic acid is produced or used. As this compound is a minor impurity in the herbicide, 4-chloro-2-methylphenoxy acetic acid (MCPA), dermal and inhalation exposure may also arise resulting from the use and production of the herbicide MCPA. (SRC)

If any symptoms of illness occur during or following inhalation of spray, remove victim from contact with the material for at least 2 to 3 days. Allow subsequent contact with chlorophenoxy compounds only if effective respiratory protection is practiced. /Chlorophenoxy compounds/

Flush chemicals from eyes with copious amounts of clean water for 10 to 15 minutes. If irritation persists, an ophthalmologic examination should be performed. If substantial amounts of chlorophenoxy compounds have been ingested, spontaneous emesis may occur. ...Administer intravenous fluids to accelerate the excretion of chlorophenoxy compounds, and to limit concentration of the toxicant in the kidney. A urine flow of 4-6 mL/minute is desirable. Intravenous saline/dextrose has sufficed to rescue comatose patients who drank 2,4-D and mecoprop several hours before hospital admission. Caution: Monitor urine protein and cells, BUN, serum creatinine, serum electrolytes, and fluid intake/output carefully to ensure that renal function remains unimpaired and that fluid overload does not occur. /Chlorophenoxy compounds/

If ... ingested, spontaneous emesis usually occurs. Ordinarily, this empties the stomach as effectively as intubation & lavage. If vigorous emesis has not occurred, measures should be taken to empty the stomach and limit gastrointestinal absorption by gastric intubation, aspiration, and lavage, following placement of a cuffed endotracheal tube. Repeated administration of charcoal at half or more the original dosage every 2-4 hours may be beneficial. If gastric aspiration and lavage is not performed due to delay in treatment, and if the patient is fully alert, administer charcoal, and laxative orally. /Chlorophenoxy compounds/

Forced alkaline diuresis has been used successfully in management of suicidal ingestions of chorophenoxy compounds, especially when initiated early. Alkalinizing the urine by adding sodium bicarbonate in the intravenous solution accelerates excretion of 2,4-D dramatically and mecoprop excretion substantially. Urine pH should be maintained between 7.6 and 8.8. Include potassium chloride as needed to offset potassium losses... . It is crucial to monitor serum electrolytes carefully, especially potassium and calcium. There may possibly be some hazard to the kidneys when urine concentrations of toxicant are very high, so the integrity of renal function and fluid balance should be monitored carefully as the chlorophenoxy compound is excreted. Renal failure has occured in patients with severe intoxication during alkaline diuresis. ... /Chlorophenoxy compounds/

For more Antidote and Emergency Treatment (Complete) data for 2-CHLOROPHENOXYACETIC ACID (8 total), please visit the HSDB record page.

YIELDS 2-CHLORO-4-HYDROXYPHENOXYACETIC ACID IN AVENA. ; YIELDS O-CHLOROPHENOL IN ARTHROBACTER.. /FROM TABLE/

FOLLOWING ADMIN OF N-CYCLOPROPYL-2-(2-CHLOROPHENOXY ETHYLAMINE-HCL (200 MG, ORALLY) TO HUMANS, 2-CHLOROPHENOXYACETIC ACID WAS IDENTIFIED IN THE URINE.

Used as a chemical reagent; May occur as a minor contaminant of the herbicide 4-chloro-2-methylphenoxy acetic acid (MCPA); [HSDB]

Chemical reagent