Propiolsure

EC50; Species: Xenopus laevis (African clawed frog, embryo); Conditions: freshwater, renewal, pH 7.0-7.8; Concentration: 4468500 ug/L for 96 hr (95% confidence interval: 4091000-5252000 ug/L); Effect: increased developmental changes, craniofacial defects, abnormal gut coiling /> or = 98% purity/

LC50; Species: Xenopus laevis (African clawed frog, embryo); Conditions: freshwater, renewal, pH 7.0-7.8; Concentration: 3421500 ug/L for 96 hr (95% confidence interval: 3066000-3726000 ug/L) /> or = 98% purity/

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1(SRC), determined from a structure estimation method(2), indicates that propiolic acid is expected to have very high mobility in soil(SRC). The pKa of propiolic acid is estimated as 1.89(3), indicating that this compound will exist entirely in anion form in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4). Volatilization from moist soil is not expected because the acid exists as an anion and anions do not volatilize(SRC). Propiolic acid is expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 3.5 mm Hg at 25 °C(SRC), determined from a fragment constant method(5). Biodegradation data were not available(SRC, 2010).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 1(SRC), determined from a structure estimation method(2), indicates that propiolic acid is not expected to adsorb to suspended solids and sediment(SRC). A pKa of 1.89(3) indicates propiolic acid will exist entirely in the anion form at pH values of 5 to 9 and therefore volatilization from water surfaces is not expected to be an important fate process(SRC). According to a classification scheme(4), an estimated BCF of 3(SRC), from an estimated log Kow of -0.19(5) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Propiolic acid is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(7). Biodegradation data were not available(SRC, 2010).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), propiolic acid, which has an estimated vapor pressure of 3.5 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase propiolic 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 5 days(SRC), calculated from its rate constant of 3.0X10-12 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Vapor-phase propiolic acid is also degraded in the atmosphere by reaction with ozone(SRC); the half-life for this reaction in air is estimated to be 380 days(SRC), calculated from its rate constant of 3.0X10-20 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Propiolic acid contains chromophores that absorb at wavelengths >290 nm(4) and therefore may be susceptible to direct photolysis by sunlight(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of propiolic acid can be estimated to be 1(SRC). According to a classification scheme(2), this estimated Koc value suggests that propiolic acid is expected to have very high mobility in soil. The pKa of propiolic acid is 1.89(3), indicating that this compound will exist entirely in anion form in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4).

/SIGNS AND SYMPTOMS/ Material is extremely destructive to tissue of the mucous membranes and upper respiratory tract, eyes, and skin., Cough, Shortness of breath, Headache, Nausea

/SIGNS AND SYMPTOMS/ Causes eye burns. Causes skin burns. May be fatal if absorbed through skin.

An estimated BCF of 3 was calculated in fish for propiolic acid(SRC), using an estimated log Kow of -0.19(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).

A pKa of 1.89(1) indicates propiolic acid will exist entirely in the anion form at pH values of 5 to 9 and therefore volatilization from water surfaces and moist soil is not expected to be an important fate process(SRC). Propiolic acid is expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 3.5 mm Hg(SRC), determined from a fragment constant method(2).

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ The developmental toxicity for each of 45 carboxylic acids /including propiolic acid/ was determined for Xenopus embryos. Acids tested included 12 unbranched, saturated aliphatics, 12 branched, saturated aliphatics, 12 unsaturated aliphatics, and 9 aromatics. Embryos were collected following hormone-induced breeding and exposed to at least eight concentrations of the acid, along with a control. For each concentration, 25 properly developing embryos were exposed to the acid solution for 96 hr. Each acid was tested on at least three separate occasions and the data were pooled to calculate 96 hr LC50 (lethality). 96 hr EC50 (malformation), and DHI (developmental hazard index = 96 hr LC50/96 hr EC50) values. The endpoint data were subjected to quantitative structure-activity relationship (QSAR) analyses and computer-automated structure evaluation (CASE). Variation in acid-induced lethality was effectively explained by partitioning and ionizability of the acids, while partitioning alone was somewhat effective in explaining variation for acid-induced malformation. The results indicated that developmental hazard of the acids to Xenopus embryos is primarily dependent on carbon-chain length, with acids containing five carbon atoms in the chain tending to be the most potent. Unsaturation reduced the hazard in comparison with the corresponding unbranched saturated acid. Developmental hazard was highest for 2-position branched compounds with a 5- or 6-C chain, but was reduced for 2-position branched acids with a 3- or 4-C chain. Hazard of the non-2 position branched acids was variable. Valproic (2-propylpentanoic) acid showed the highest developmental hazard with Xenopus, twice that of any other acid tested.

The rate constant for the vapor-phase reaction of propiolic acid with photochemically-produced hydroxyl radicals has been estimated as 3.0X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 5 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the vapor-phase reaction of propiolic acid with ozone has been estimated as 3.0X10-20 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(1). This corresponds to an atmospheric half-life of about 380 days at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(2). Propiolic acid is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(3). Propiolic acid contains chromophores that absorb at wavelengths >290 nm(3) and therefore may be susceptible to direct photolysis by sunlight(SRC).

Propiolic acid's production and use as a laboratory reagent may result in its release to the environment through various waste streams. If released to air, an estimated vapor pressure of 3.5 mm Hg at 25 °C indicates propiolic acid will exist solely as a vapor in the atmosphere. Vapor-phase propiolic acid will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and with ozone; the half-lives for these reactions in air are estimated to be 5 and 380 days, respectively. Propiolic acid contains chromophores that absorb at wavelengths >290 nm and therefore may be susceptible to direct photolysis by sunlight. If released to soil, propiolic acid is expected to have very high mobility based upon an estimated Koc of 1. The pKa of propiolic acid is 1.89, indicating that this compound will exist entirely in anion form in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts. Volatilization from moist soil is not expected because the acid exists as an anion and anions do not volatilize. Propiolic acid may volatilize from dry soil surfaces based upon its vapor pressure. Biodegradation data were not available. If released into water, propiolic acid is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. The pKa value indicates propiolic acid will exist in the anion form at pH values of 5 to 9 and therefore volatilization from water surfaces and moist soil is not expected to be an important fate process. An estimated BCF of 3 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 propiolic acid may occur through inhalation and dermal contact with this compound at workplaces where propiolic acid is produced or used. (SRC)