Diphenylmethane

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity 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 and plant life; and conformance with environmental and public health regulations.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

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. The completeness of the cleaning procedures should be considered before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at the end of shift, but should remain at employee's place of work for cleaning.

6.8 [mg/m3]

74 [mg/m3]

450 [mg/m3]

IN EVENT OF SPILLAGE OR LEAKAGE OF HOT FLUIDS, APPROVED CHEM CARTRIDGE RESPIRATORS OR MASKS SHOULD BE WORN FOR PROTECTION AGAINST VAPORS. SKIN CONTACT WITH TERPHENYLS AND POSSIBLY WITH DIPHENYL AND DERIVATIVES SHOULD BE AVOIDED BY PROPER HANDLING PROCEDURES. CONTAMINATED CLOTHING MUST BE LAUNDERED BEFORE USE. EYE PROTECTION SHOULD BE WORN IF EYE HAZARD EXISTS. /DIPHENYL & DERIVATIVES/

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 9160(SRC), determined from a structure estimation method(2), indicates that 1,1'-methylenebisbenzene is expected to be immobile in soil(SRC). Volatilization of 1,1'-methylenebisbenzene from moist soil surfaces may be an important fate process(SRC) given an estimated Henry's Law constant of 1.3X10-4 atm-cu m/mole(SRC), derived from its vapor pressure, 8.61X10-3 mm Hg(3), and water solubility, 14.1 mg/L(4). However, adsorption to soil is expected to attenuate volatilization(SRC). Biodegradation is expected to be an important fate process in soil. 1,1'-Methylenebisbenzene has been shown to biodegrade readily in river die-away tests(5) and in soil inoculum studies following acclimation(6). A 0% of theoretical BOD using activated sludge in a 2-week Japanese MITI test(7) suggests that biodegradation is not an important environmental fate process in soil(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 9160(SRC), determined from a structure estimation method(2), indicates that 1,1'-methylenebisbenzene 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 1.3X10-4 atm-cu m/mole(SRC), derived from its vapor pressure, 8.61X10-3 mm Hg(4), and water solubility, 14.1 mg/L(5). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 13 hours and 8 days, respectively(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 116 days if adsorption is considered(6). According to a classification scheme(7), a measured BCF range of 452 to 1190 in catfish(8), suggests bioconcentration in aquatic organisms is high to very high(SRC). Biodegradation is expected to be an important fate process in water. 1,1'-Methylenebisbenzene has been shown to biodegrade readily in river die-away tests(9) and in soil inoculum studies following acclimation(10). A 0% of theoretical BOD using activated sludge in a 2-week Japanese MITI test(8) suggests that biodegradation is not an important environmental fate process in water(SRC). Hydrolysis is not expected to be an important environmental fate process(SRC) since this compound lacks functional groups that hydrolyze under environmental conditions(3).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 1,1'-methylenebisbenzene, which has a vapor pressure of 8.21X10-3 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. However, monitoring data indicates that 1,1'-methylenebisbenzene is found on particulate matter in the ambient atmosphere(3); the source of atmospheric particulate matter containing 1,1'-methylenebisbenzene may be fly ash from municipal incinerators(4,5). Vapor-phase 1,1'-methylenebisbenzene 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 1.5 days(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(6). Particulate-phase 1,1'-methylenebisbenzene may be removed from the air by wet and dry deposition(SRC). 1,1'-Methylenebisbenzene has a UV absorption band that extends beyond 290 nm(7), therefore, it may be susceptible to direct photolysis by sunlight(SRC).

In a comprehensive survey of wastewater from 4000 industrial and publicly owned treatment works (POTWs) sponsored by the Effluent Guidelines Division of the US EPA, 1,1'-methylenebisbenzene was identified in discharges of the following industrial category (frequency of occurrence, median concentration in ppb): timber products (1; 70.9), paint and ink (3; 34.8), printing and publishing (1; 38.5), coal mining (2; 75.7), organics and plastics (10; 356.6), plastics and synthetics (1; 28.6), rubber processing (1; 207.1), pesticides manufacture (1; 281.4), pharmaceuticals (6; 204.7), explosives (2; 40.6), electronics (1; 43.8), oil and gas extraction (1; 43.8), organic chemicals (3; 1183.3), publicly owned treatment works (20; 18.2). The highest effluent concentration was 29,554 ppb in the paint and ink industry(1).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of 1,1'-methylenebisbenzene can be estimated to be 9160(SRC). According to a classification scheme(2), this estimated Koc value suggests that 1,1'-methylenebisbenzene is expected to be immobile in soil.

/HUMAN EXPOSURE STUDIES/ A maximization test was carried out on 25 volunteers. The material was tested at a concn of 8% in petrolatum and produced no sensitization.

/SIGNS AND SYMPTOMS/ PROBABLE IRRITANT & CNS DEPRESSION HIGH CONCN.

1,1'-Methylenebisbenzene's production and use in organic synthesis and dyes(1) and in the fragrance industry as both a fixative and scenting agent in soaps(2) may result in its release to the environment through various waste streams(SRC). 1,1'-Methylenebisbenzene is emitted from municipal incinerators in fly ash and may leach from the fly ash in landfills(3).

AEROBIC: When seeded with a soil inoculum, 1,1'-methylenebisbenzene underwent extensive degradation in 40 days, following a 30 day lag(1). 1,1'-Methylenebisbenzene was completely degraded within 5 days in a river die-away test(2); the study found that, in general, 1,1'-methylenebisbenzene compunds having an unsubstituted phenyl ring undergo rapid primary biodegradation(2). 1,1'-Methylenebisbenzene is degraded by microorganisms isolated from sewage, water, soil, and leaves(3-5). Three metabolic pathways have been identified leading to the initial metabolic product 1,1,1',1'-tetraphenyldimethyl ether, phenylacetic acid, and benzhydrol(3). 1,1'-Methylenebisbenzene, present at 100 mg/L, reached 0% of its theoretical BOD in 2 weeks using an activated sludge inoculum at 30 mg/L in the Japanese MITI test(6).

Using catfish which were exposed over an 8-week period to 1,1'-methylenebisbenzene concentrations of 0.01 mg/L and 0.1 mg/L, 1,1'-methylenebisbenzene BCF values were measured that ranged from 452 to 1190(1). According to a classification scheme(3), this BCF range suggests the potential for bioconcentration in aquatic organisms is high to very high(SRC).