tert-Butylbenzol

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

7.5 [mg/m3]

83 [mg/m3]

500 [mg/m3]

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1181(SRC), determined from a structure estimation method(2), indicates that t-butylbenzene is expected to have low mobility in soil(SRC). Volatilization of t-butylbenzene from moist soil surfaces is expected to be an important fate process(SRC) given an Henry's Law constant of 1.32X10-2 atm-cu m/mole(3), derived from its vapor pressure, 2.20 mm Hg(4), and water solubility, 29.5 mg/l(5). The potential for volatilization of t-butylbenzene from dry soil surfaces may exist(SRC) based upon its vapor pressure(4). However, adsorption to soil is expected to attenuate volatilization(SRC). Biodegradation from soil may occur based on activated sludge study results(6-9).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 1181(SRC), determined from a structure estimation method(11), indicates that t-butylbenzene is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 1.32X10-2 atm-cu m/mole(4), derived from it's vapor pressure of 2.20 mm Hg(7) and water solubility of 29.5 mg/l(8). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 1 hr and 4 days, respectively(SRC). The volatilization half-life from a model pond is 30 days if adsorption is considered(9). According to a classification scheme(5), an estimated BCF of 291(SRC), from its log Kow of 4.11(2) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is high. Biodegradation from water may occur(10).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), t-butylbenzene, which has a vapor pressure of 2.20 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase t-butylbenzene 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 3 days(SRC), calculated from its rate constant of 4.60X10-12 cu cm/molecule-sec at 25 °C(3).

t-Butylbenzene was detected, not quantified in the raw influent to a waste treatment system at a polyester finishing plant effluent(1). The compound was identified as a volatile from pre-aeration wastewater samples taken from a sewage treatment plant in Singapore(4). It was also identified as one of the 400 gas-phase hydrocarbon compounds in emissions from gasoline-powered motor vehicles in highway operation in the Allegheny Mountain Tunnel of the Pennsylvania Turnpike in 1979(2). t-Butylbenzene has been identified in effluent resulting from coal/refuse combustion(3).

Soil (Mediterranean red sandy clay) samples with different moisture contents (0.0, 0.8, 4.0, and 12%, wt/wt) were contaminated by vapors and/or liquid from a mixture containing 5 kerosene components (m-xylene, pseudo-cumene, t-butylbenzene (6.67% by vol), n-decane and n-dodecane). Vapor adsorption was found to be dependent on the vapor concn of each component and on the soil moisture content. Adsorption of t-butylbenzene on soil was 50 and 15 ug/g at 7 °C, 120 and 47 at 17 °C, 210 and 60 at 27 °C, and 330 and 100 ug/g at 34 °C for oven dried and air dried soil, respectively. The sorption coefficients of t-butylbenzene decr with incr temp but showed only a very slight variability between 20 and 34 °C, in air-dried soil. Volatilization from soil was high: 92.5% of t-butylbenzene was desorbed in less than 2 hr, and 99.7% in 16 hr.

Using a structure estimation method based on molecular connectivity indices(1), the Koc for t-butylbenzene can be estimated to be 1181(SRC). According to a classification scheme(2), this estimated Koc value suggests that t-butylbenzene is expected to have low mobility in soil.

Acute oral toxicity was evaluated in groups of 10 ChR-CD male rats administered a single dose of tert-butyl-benzene by oral gavage at dose levels of 3000, 3400 and 3800 mg/kg body weight. Mortality was observed in one rat at 3000 mg/kg, 2 rats at 3400 mg/kg and 9 rats at 3800 mg/kg body weight; the LD50 value was calculated to be 3503 mg/kg body weight. Clinical observations after dosing included rapid and labored respiration, salivation, prostration, lacrimation, stained nose and mouth, diarrhea, chromodacryorrhea, a stained and wet perineal area, weakness, alopecia on the abdomen, stained eyes, stained abdominal area, and lethargy. Animals at all dose levels exhibited weight loss after dosing. Gross necropsy was not reported.

Acute dermal toxicity was evaluated in 4 male and 4 female rats receiving single occluded, percutaneous doses of undiluted tertiary butyl benzene at a dose level of 2000 mg/kg of body weight. The test article was held in contact with the intact skin for a 24 hour period. Mortality was not observed witihn 14 days of treatment and the LD50 was estimated to be greater than 2000 mg/kg of body weight. Clinical observation revealed no signs of intoxiciation. Gross necropsy was not reported.

Acute inhalation toxicity was evaluated in groups of 5 male and 5 female Wistar strain rats exposed to tertiary butyl benzene at measured concentrations of 4.0, 4.4 and 4.6 mg/lof air. The test armosphere was generated by using a thermostated wick-type saturator. Mortality was observed within 14 days of treatment in 3 of the female rats at the 4.6 mg/l dose; the LC50 was estimated to be approximately 4.6 mg/l. Clinical observations included salivation, lachrymation, a high stepping gait, dyspnoea, fasiculations, tremors, endophthalamus, and convulsions. Gross necropsy evaluation revealed no pathological changes in the survivors but was not reported for those animals that died.

The frequency of chromosomal aberrations was evaluated in vitro by exposing rats liver (RL1) cells to 10, 20 and 40 ug/ml of tertiary butyl benzene. No increases in the frequency of chromatid gaps, chromatid breaks or total chromosome aberrations was observed at any dose level. Tertiary butyl benzene did not induce chromosome damage in this assay.

For more TSCA Test Submissions (Complete) data for T-BUTYLBENZENE (6 total), please visit the HSDB record page.

URBAN/SUBURBAN: t-Butylbenzene was detected using gas chromatographic analysis of Paris air during the fall of 1972(1). The ambient air of the Los Angeles, CA basin contained t-butylbenzene at concns ranging from 0.019 to 0.045 ppm v/v(2). t-Butylbenzene was detected in the ambient air of the Kanawha Valley, WV, Houston, TX and vicinity, and the Los Angeles, CA basin(3). It was detected in ambient air of Los Angeles, CA during 1966-1968 and in Azusa, CA in 1967(4).

SOURCE DOMINATED: t-Butylbenzene was identified not quantified in the air of six industrial cities of the USSR(1). t-Butylbenzene was detected at concns ranging from 0 to 39 ug/cu m in ambient air samples from six sites around Gatwick Airport, London, collected during August to November 1979(2).

t-Butylbenzene's production and use as a chemical intermediate and solvent(1) may result in its release to the environment through various waste streams(SRC). A composite gasoline sample obtained in Los Angeles, CA contained 0.12% t-butylbenzene by weight(2).

AEROBIC: t-Butylbenzene reached 0.3% of its theoretical BOD using an acclimated activated sludge inoculum and the 5-day BOD test at 20 °C(1). Theoretical BODs ranging from 0.6% to 39.8% were measured using the Warburg test(1,3-5). Alkylbenzenes are known to be oxidized by microorganisms(2). t-Butylbenzene was degraded using Moustorod Refinery wastewater inoculum, exhibiting 14, 100, and 100 % degradation in 7, 15, and 23 days, respectively; similar results were observed in non-aerated tests(6). t-Butylbenzene at a concn of 19-25 ppm was 10 and 30% removed after 20 and 80 days, respectively, in a grab sample study using water from the Ohio River, although volatilization could not be ruled out(7). Biological loss of t-butylbenzene was noted using artificial seawater acclimated with 100 ml gas oil at 20 °C for 3 days and then inoculated with North Sea coast water although the sample compound could not be resolved from 1,2,4-trimethylbenzene(8). t-Butylbenzene at a concn of 100 mg/l in an automated continuous respirometer study resulted in a growth rate of 1.21 1/day using an activated sludge inoculum following a lag of 4.40 days(9).

An estimated BCF of 291 was calculated for t-butylbenzene(SRC), using a log Kow of 4.11(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is high.

Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. t-Butylbenzene is included on this list.

(CA) CALIFORNIA 260 ug/l

(FL) FLORIDA 280 ug/l

(NH) NEW HAMPSHIRE 260 ug/L