Dipentyl phthalate

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.

SMALL SPILLS AND LEAKAGE: If you spill this chemical, FIRST REMOVE ALL SOURCES OF IGNITION. Then, use absorbent paper to pick up all liquid spill material. Your contaminated clothing and absorbent paper should be sealed in a vapor-tight plastic bag for eventual disposal. Solvent wash all contaminated surfaces with 60-70% ethanol followed by washing with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.

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: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at end of shift, but should remain at employee's place of work for cleaning.

RECOMMENDED RESPIRATOR: Where the neat test chemical is weighed and diluted, wear a NIOSH-approved half face respirator equipped with an organic vapor/acid gas cartridge (specific for organic vapors, HCl, acid gas and SO2) with a dust/mist filter. (NTP, 1992)

Phthalate esters are endocrine disruptors. Animal studies have shown that they disrupt reproductive development and can cause a number of malformations in affected young, such as reduced anogenital distance (AGD), cryptorchidism, hypospadias, and reduced fertility. The combination of effects associated with phthalates is called 'phthalate syndrome’. (A2883)

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 27,000(SRC), determined from a log Kow values of 5.62(2), and a regression-derived equation(3), indicate that diamyl phthalate is expected to be immobile in soil(SRC). Volatilization of diamyl phthalate from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 8.9X10-7 atm-cu m/mole(SRC), using a fragment constant estimation method(4). Diamyl phthalate is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 2.0X10-4 mm Hg(SRC), determined from a fragment constant method(5). Biodegradation studies using pure cultures indicate that diamyl phthalate may biodegrade under aerobic conditions yielding phthalic acid and amyl alcohol(6). Although biodegradation data on diamyl phthalate are limited, biodegradation studies on a series of phthalate esters have demonstrated that, in general, phthalate esters are readily biodegraded(7).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 27,000(SRC), determined from a log Kow values of 5.62(2), and a regression-derived equation(3), indicate that diamyl phthalate is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 8.9X10-7 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). According to a classification scheme(5), an estimated BCF of 420(SRC), from its log Kow(2) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is high, provided the compound is not metabolized by the organism(SRC). However, bioconcentration studies on compounds which are structurally similar suggest that bioconcentration may be lower than that indicated by the regression-derived equations due to the ability of aquatic organisms to readily metabolize this class of compounds(7). Estimated hydrolysis half-lives of 3.4 years and 130 days at pHs 7 and 8, respectively, suggest that hydrolysis is not expected to be an important process(8). Biodegradation studies using pure cultures indicate that diamyl phthalate may biodegrade under aerobic conditions yielding phthalic acid and amyl alcohol(9). Although biodegradation data on diamyl phthalate are limited, biodegradation studies on a series of phthalate esters have demonstrated that, in general, phthalate esters are readily biodegraded(10).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), diamyl phthalate, which has an estimated vapor pressure of 2.0X10-4 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 diamyl phthalate 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 32 hours(SRC), calculated from its rate constant of 1.2X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Diamyl phthalate does contain chromophores that absorb at wavelengths >290 nm(4) and therefore may be susceptible to direct photolysis by sunlight(SRC).

Phthalate esters are endocrine disruptors. They decrease foetal testis testosterone production and reduce the expression of steroidogenic genes by decreasing mRNA expression. Some phthalates have also been shown to reduce the expression of insulin-like peptide 3 (insl3), an important hormone secreted by the Leydig cell necessary for development of the gubernacular ligament. Animal studies have shown that these effects disrupt reproductive development and can cause a number of malformations in affected young. (A2883)

The following link will take the user to the National Toxicology Program (NTP) Test Agent Search Results page, which tabulates all of the "Standard Toxicology & Carcinogenesis Studies", "Developmental Studies", and "Genetic Toxicity Studies" performed with this chemical. Clicking on the "Testing Status" link will take the user to the status (i.e., in review, in progress, in preparation, on test, completed, etc.) and results of all the studies that the NTP has done on this chemical. [http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm?fuseaction=ntpsearch.searchresults&searchterm=131-18-0][Available from: http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm?fuseaction=ntpsearch.searchresults&searchterm=131-18-0]

The Koc of diamyl phthalate is estimated as 27,000(SRC), using a log Kow of 5.62(1), and 5.66(2), respectively, and a regression-derived equation(2). According to a classification scheme(4), this Koc value suggests that diamyl phthalate is expected to be immobile in soil.

/ALTERNATIVE and IN VITRO TESTS/ /It was/ previously found that some phthalates have nongenomic effects, exerting inhibitory effects on the functional activities of nicotinic acetylcholine receptors (nAChRs) in bovine chromaffin cells. ... This study ... investigated the effects of eight phthalates on the calcium signaling of human nAChR by using human neuroblastoma SH-SY5Y cells. All eight phthalates, with different potency, have inhibitory roles on the calcium signaling coupled with human nAChR, but not muscarinic acetylcholine receptors (mAChRs). For inhibition of human nAChR, the strongest to weakest potencies were observed as di-n-pentyl phthalate (DPP) --> butyl benzyl phthalate (BBP) --> di-n-butyl phthalate (DBP) --> dicyclohexyl phthalate (DCHP) --> di-n-hexyl phthalate (DHP) --> di-(2-ethyl hexyl) phthalate (DEHP) --> di-n-propyl phthalate (DPrP) --> diethyl phthalate (DEP). The potencies of phthalates were associated with their structures such that the most effective ones had dialkyl group carbon numbers of C4 or C5, with shorter or longer numbers resulting in decreased potency. At as low as 0.1 uM, DPP, DBP, BBP, DCHP and DHP significantly inhibited the calcium signaling of human nAChR. The IC50 of phthalates on human nAChR, ranging from 0.32 to 7.96 uM, were 10-50 lower than those for bovine nAChR.

AEROBIC: When diamyl phthalate was incubated with pure cultures of Pseudomonas acidovorans under aerobic conditions, the initial products from this reaction were phthalic acid and amyl alcohol(1). Although the biodegradation of diamyl phthalate has not been studied, biodegradation studies on a series of phthalate esters have demonstrated that in general phthalate esters are readily biodegraded(2).