Isodecyl octyl phthalate

Using a structure estimation method based on molecular connectivity indices(1), the Koc of isodecyl octyl phthalate can be estimated to be 5.6X10+5(SRC). According to a classification scheme(2), this estimated Koc value suggests that isodecyl octyl phthalate is expected to be immobile in soil.

An estimated BCF of 3 was calculated in fish for isodecyl octyl phthalate(SRC), using an estimated log Kow of 9.45(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 Henry's Law constant for isodecyl octyl phthalate is estimated as 2.1X10-5 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that isodecyl octyl phthalate is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 4.7 days(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 40 days(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 220 years if adsorption is considered(3). Isodecyl octyl phthalate is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.1X10-7 mm Hg(SRC), determined from a fragment constant method(4).

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ The effects of 8 phthalic acid esters, commonly used as plasticizers in polyvinyl chloride plastics, injected into the yolk sac of chick embryos, between the 65th and 72nd hr of development, were studied. Octyl isodecyl phthalate damaged the CNS of developing embryos, as indicated after hatching by grossly abnormal behavior of the chicks, such as tremor, nonpurposeful bodily movement, and inability to stand or walk normally.

The rate constant for the vapor-phase reaction of isodecyl octyl phthalate with photochemically-produced hydroxyl radicals has been estimated as 2.3X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 16 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). A base-catalyzed second-order hydrolysis rate constant of 0.046 L/mole-sec(SRC) was estimated using a structure estimation method(2); this corresponds to half-lives of 4.7 years and 170 days at pH values of 7 and 8, respectively(2). Isodecyl octyl phthalate does contain chromophores that absorb at wavelengths >290 nm(3) and therefore may be susceptible to direct photolysis by sunlight(SRC).

Occupational exposure to isodecyl octyl phthalate may occur through inhalation of aerosols and dermal contact with this compound at workplaces where isodecyl octyl phthalate is produced or used. Use data indicate that the general population may be exposed to isodecyl octyl phthalate via dermal contact products containing this compound. (SRC)

Isodecyl octyl phthalate's production and use as a plasticizer may result in its release to the environment through various waste streams. If released to air, an estimated vapor pressure of 1.1X10-7 mm Hg at 25 °C indicates isodecyl octyl phthalate will exist in both the vapor and particulate phases in the atmosphere. Vapor-phase isodecyl octyl phthalate 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 16 hours. Particulate-phase isodecyl octyl phthalate will be removed from the atmosphere by wet or dry deposition. Isodecyl octyl phthalate does contain chromophores that absorb at wavelengths >290 nm and therefore may be susceptible to direct photolysis by sunlight. If released to soil, isodecyl octyl phthalate is expected to have no mobility based upon an estimated Koc of 5.6X10+5. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 2.1X10-5 atm-cu m/mole. However, adsorption to soil is expected to attenuate volatilization. Although biodegradation data on isodecyl octyl phthalate were not available, biodegradation studies on a series of phthalate esters have demonstrated that phthalate esters in general are readily biodegraded. If released into water, isodecyl octyl phthalate is expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 4.7 and 40 days, respectively. However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 220 years if adsorption is considered. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important process based on estimated hydrolysis half-lives of 4.7 years and 170 days at pHs 7 and 8, respectively. Occupational exposure to isodecyl octyl phthalate may occur through inhalation of aerosols and dermal contact with this compound at workplaces where isodecyl octyl phthalate is produced or used. Use data indicate that the general population may be exposed to isodecyl octyl phthalate via dermal contact products containing this compound. (SRC)