United States Pollution Prevention December 1994 Environmental and Toxics EPA 749-F-95-005a Protection Agency (7407) OPPT Chemical Fact Sheets Butyraldehyde Fact Sheet: Support Document (CAS No. 123-72-8) This summary is based on information retrieved from a systematic search limited to secondary sources (see Appendix A). These sources include online databases, unpublished EPA information, government publications, review documents, and standard reference materials. No attempt has been made to verify information in these databases and secondary sources. I. CHEMICAL IDENTITY AND PHYSICAL/CHEMICAL PROPERTIES The chemical identity and physical/chemical properties of butyraldehyde are summarized in Table 1. TABLE 1. CHEMICAL IDENTITY AND CHEMICAL/PHYSICAL PROPERTIES OF BUTYRALDEHYDE Characteristic/Property Data Reference ____________________________________________________________________________ CAS No. 123-72-8 Common Synonyms butanal Budavari et al. 1989 Molecular Formula C4H8O Chemical Structure CH3CH2CH2 CHO Physical State clear, colorless liquid Keith and Walters 1985 Molecular Weight 72.10 Budavari et al.1989 Melting Point -99øC Budavari et al.1989 Boiling Point 74.8øC Budavari et al.1989 Water Solubility 71 g/L @ 25øC CHEMFATE 1994 Density 0.802 g/mL Budavari et al.1989 Vapor Density (air = 1) 2.48 Verschueren 1983 KOC 9.4 (calculated) CHEMFATE 1994 Log KOW 0.88 (measured) CHEMFATE 1994 Vapor Pressure 111.4 mm Hg at 25øC CHEMFATE 1994 Reactivity flammable; reacts with Keith and Walters 1985 oxidizing materials, acids Flash Point -6.67øC (closed cup) Budavari et al. 1989 Henry's Law Constant 1.15 x 10-4 atm m3/mol CHEMFATE 1994 Bioconcentration Factor 2.75 (calculated) CHEMFATE 1994 Odor Threshold 0.0046 ppm Verschueren 1983 Conversion Factors 1 ppm = 2.9 mg/m3 Verschueren 1983 1 mg/m3 = 0.34 ppm ____________________________________________________________________________ II. PRODUCTION, USES, AND TRENDS A. Production USITC (1994) identified four producers of butyraldehyde in the United States in 1992; TRI92 (1994) identified one additional producer. These five producers are listed in Table 2. In 1992, the U.S. production volume of butyraldehyde was 1,876 million pounds (852,792,000 kilograms; see Table 3). This was a decrease from the 1991 production volume of 1,914 million pounds. TABLE 2. U.S. PRODUCERS OF BUTYRALDEHYDE AND THEIR CAPACITIES Producer Plant Location 1994 Plant Capacity (Millions of Pounds) ________________________________________________________________________ Aristech Chemical Company Pasadena, TX N/A BASF Corporation Freeport, TX N/A Eastman Kodak Company, Texas Eastman Company Division Longview, TX N/A Hoechst Celanese Corporation, Chemical Group, Inc. Bay City, TX N/A Union Carbide Corporation, Industrial Chemicals Division Texas City, TX N/A _______________________________________________________________________ N/A: Not available Source: USITC (1994); TRI92 (1994) TABLE 3. U.S. PRODUCTION AND SALES OF BUTYRALDEHYDE Year Production Sales Quantity Sales Value Average Unit (Millions (Millions of ($1,000s) Value of Pounds) Pounds) (Per Pound) _______________________________________________________________________ 1992 1,876 623 13,714 $0.21 1991 1,914 695 16,106 $0.23 1990 1,891 740 16,005 $0.30 1989 1,679 N/A N/A N/A _______________________________________________________________________ N/A: Not available Sources: USITC 1991, 1992, 1993, 1994. B. Uses Butyraldehyde is used as an intermediate in the production of synthetic resins, rubber accelerators, solvents, plasticizers, and high molecular weight polymers (Grayson 1985; Sax and Lewis 1987; Windholz 1983). See Table 4 for applicable standard industrial classification (SIC1) codes. TABLE 4. END USE PATTERN OF BUTYRALDEHYDE--1992 ESTIMATE Derivative [Typical Standard Industrial Classification (SIC) Code] Percentage of U.S. Use ___________________________________________________________________ Production of Synthetic Resins N/A (SIC 2821) Production of Rubber Accelerators N/A (SIC 2869) Production of Solvents N/A (SIC 2869) Production of Plasticizers N/A (SIC 2869) Production of High Molecular Weight Polymers N/A (SIC 2821) __________________________________________________________________ N/A: Not Available Sources: Grayson 1985; Sax and Lewis 1987; Windholz 1983 ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ 1 The Standard Industrial Classification (SIC) code is the statistical classification standard for all Federal economic statistics. The code provides a convenient way to reference economic data on industries of interest to the researcher. SIC codes presented here are not intended to be an exhaustive listing; rather, the codes listed should provide an indication of where a chemical may be likely to be found in commerce. C. Trends Demand for butyraldehyde is expected to remain steady for the next few years. III. ENVIRONMENTAL FATE A. Environmental Release Dynamac Corporation (1988) has summarized the occurrence of butyraldehyde in the environment. Butyraldehyde occurs naturally in essential oils of plants and in foods such as fruits, vegetables, cheeses, meat, wines, coffee, honey, and nuts. It has been identified as a metabolite of the poplar tree and as a volatile component of ferns. Butyraldehyde is released to the environment from facilities that manufacture and use it. Exposure in the workplace occurs mainly during sampling, loading and unloading of shipping containers, and maintenance of equipment. Levels as high as 21.3 ppm have been detected for materials-handling workers (8-hour geometric mean time-weighted average, 3.7 ppm). Butyraldehyde has been detected in exhaust emissions from diesel engines (0.08 microliters/L), in gaseous emissions from fireplaces burning jack pine or red oak logs (0.010 to 0.901 g/kg), at hazardous waste sites (an average concentration of 130 ppb in soil, water, and waste samples), and in mother's milk. Urban air samples contained 0.2 to 6 parts per billion (ppb) butyraldehyde. It has also been detected in a surface water sample from the Mississippi River basin and in a marine surface water sample taken from the straits of Florida (22 mg/L). In 1992, environmental releases of the chemical, as reported to the Toxics Release Inventory by certain types of US industries, totaled about 625,000 pounds, including 496 thousand pounds to the atmosphere, 128 thousand pounds to underground injection sites, 470 pounds to surface water, and 256 pounds to land (TRI92 1994). B. Transport Based on one calculation, up to 97% of the butyraldehyde released to any medium would partition to the atmosphere (Dynamac Corporation 1988). However, the vapor pressure (111.4 mm Hg at 25øC), water solubility (71,000 mg/L), and log Kow value (0.88) for butyraldehyde suggest that the chemical would partition to both air and water (Dynamac Corporation 1988; CHEMFATE 1994). In the atmosphere, butyraldehyde would exist primarily in the vapor phase with a small fraction adsorbed to particulates (HSDB 1994). Its removal from air may occur through wet deposition (HSDB 1994). Butyraldehyde released to water would volatilize with a half-life of about 12 hours, based on its Henry's Law constant (1.15 x 10-4 atm m3/mol) (CHEMFATE 1994; Dynamac Corporation 1988). Volatilization half-lives of 9 hours and 4.1 days have been estimated for a model river (1 meter deep) and a pond, respectively (HSDB 1994). If released to soil, butyraldehyde will either leach through the soil (KOC of 9.4) or evaporate from soil surfaces (HSDB 1994; CHEMFATE 1994). C. Transformation/Persistence 1. Air Butyraldehyde released to the atmosphere is removed primarily by reaction with photochemically-produced hydroxyl radicals (half-life, 16.4 hours) (HSDB 1994). Butyraldehyde may also undergo direct photolysis (HSDB 1994). 2. Water In water, the major fate processes for butyraldehyde are volatilization (see section III.B) and biodegradation (HSDB 1994). Butyraldehyde is subject to both aerobic and anaerobic biodegradation (Dynamac Corporation 1988). Using various types of inocula, 5-day biological oxygen demand (BOD) values ranging from 28 to 106% have been observed under aerobic conditions (HSDB 1994). Under anaerobic conditions, butyraldehyde was degraded 99% in a Hungate serum bottle (after a 7-day lag period) and 82% in a reactor (after 52 days of acclimation) (Dynamac Corporation 1988; HSDB 1994). 3. Soil Evaporation, leaching (see section III.B), and biodegradation are the primary fate processes for butyraldehyde in soil (see section III.C.2). 4. Biota Based on the measured log KOW of 0.88 and the water solubility of 71,000 mg/L for butyraldehyde, the estimated bioconcentration factor (BCF) values are 2.75 and 1.13, respectively, indicating a low potential for bioconcentration in aquatic organisms (HSDB 1994). IV. HEALTH EFFECTS A. Pharmacokinetics 1. Absorption No information was found in the secondary sources searched regarding the absorption of butyraldehyde. Results from toxicity studies presented in Section IV.C suggest absorption of butyraldehyde occurs by the oral and inhalation routes. 2. Distribution No information was found in the secondary sources searched regarding the distribution of butyraldehyde in the body. 3. Metabolism Aldehydes, in general, are metabolized to the corresponding acids by the enzyme aldehyde dehydrogenase (Brabec 1981; Dynamac Corporation 1988). This enzyme has been found in every organ of the body that has been studied with the highest activity being in the liver (Dynamac Corporation 1988). The acid metabolite is condensed with coenzyme A and serves as a substrate for fatty acid oxidation and the Krebs cycle (Brabec 1981). Conjugation with glutathione may also occur (Brabec 1981). 4. Excretion No other information was found regarding the excretion of butyraldehyde; however, glutathione conjugates from similar chemicals have been detected in the urine of experimental animals (Brabec 1981). B. Acute Effects Butyraldehyde liquid and vapor damage the eyes and irritate the skin. Generally, the chemical has low acute lethality to laboratory animals. 1. Humans Human volunteers exposed to butyraldehyde vapor at 230 ppm for 30 minutes reported no eye irritation (Dynamac Corporation 1988). In six cases of industrial corneal injury associated with exposure to butyraldehyde, recovery was rapid and complete (HSDB 1994; Dynamac Corporation 1988). Butyraldehyde liquid is irritating to the skin (HSDB 1994; Dynamac Corporation 1988). 2. Animals The oral LD50 of butyraldehyde in the rat ranges from 2.5 to 5.9 g/kg; the inhalation LC50 in the rat is approximately 60,000 ppm (Brabec 1981; Dynamac Corporation 1988). The chemical is moderately irritating to guinea pig skin and severely irritating to rabbit eyes (Brabec 1981). Bronchial and alveolar edema occurred in rats exposed by inhalation to high levels (not defined) (Brabec 1981). Fatal pulmonary edema has been seen in mice, guinea pigs, and rabbits exposed by inhalation to high levels (Brabec 1981). No signs of toxicity were observed in rats receiving twelve 6-hour inhalation exposures to 1000 ppm (Dynamac Corporation 1988). C. Subchronic/Chronic Effects High doses of butyraldehyde administered to animals by oral or inhalation exposure cause lesions of the stomach and respiratory tract, respectively, and decreased body weight. 1. Humans No information was found in the secondary sources searched regarding the noncarcinogenic subchronic or chronic effects of butyraldehyde in humans. 2. Animals Male and female rats were treated by gavage with 0, 0.075, 0.15, 0.3, 0.6, or 1.2 g of butyraldehyde/kg 5 days/week for 13 weeks (Dynamac Corporation 1988). In both sexes, a dose-related increase in mortality and a decrease in body weight were observed. There was an increased incidence of irritation, inflammation, necrosis, hyperplasia and lesions of the forestomach and gastric mucosa with 100% of males and 90% of females affected in the high-dose group. Rats exposed by inhalation to butyraldehyde concentrations of 2710 mg/m3 (934 ppm) for 6 hours/day, 5 days/week, for 20 exposures had oral discharge and increased adrenal and lung weights; no effects were seen at 930 mg/m3 (320 ppm) (U.S. EPA 1989b). Rats and dogs were exposed by inhalation to 0, 125, 500, or 2000 ppm 6 hours/day, 5 days/week for 13 weeks (U.S. EPA 1989a). Rats had mortality (1 animal at 2000 ppm), decreased alkaline phosphatase (500 ppm), altered blood chemistry and decreased red blood cell and monocyte counts (ò125 ppm), and lesions of the nasal epithelium and pneumonia (ò125 ppm). Dogs had elevated levels of albumin (at 125 ppm) and nasal mucosal lesions (ò500 ppm). Rats, mice, guinea pigs, rabbits, and dogs were exposed by inhalation to 0, 2000, 3100, or 6400 ppm butyraldehyde 6 hours/day, 5 days/week, for 9 days over a 2-week period (U.S. EPA 1989a). Mortality occurred in all species at 6400 ppm; decreased body weights occurred at ò3100 ppm for guinea pigs and mice and at ò2000 ppm for rats; decreased relative kidney and liver weights occurred in rats at ò2000 ppm; and hemorrhage of the ethmoturbinates occurred in one high dose rat. D. Carcinogenicity There is insufficient evidence in either humans or animals to classify butyraldehyde as a carcinogen. 1. Humans An epidemiology study of workers at an acetyl production plant indicated an increase in tumors of the nasal passage, oral cavity, and bronchial airways; however, tumors appeared after relatively short exposure periods and there were multiple chemical exposures (Brabec 1981). In a group of 150 factory workers with more than 20 years of exposure, 9 cases of carcinoma were reported. Multiple aldehydes, including butyraldehyde, and alcohols were detected in the air (Dynamac Corporation 1988). 2. Animals According to Dynamac Corporation (1988), "plans for a chronic inhalation bioassay of butyraldehyde were dropped by NTP because of technical difficulties in generating the atmosphere for exposure". E. Genotoxicity Results from short term mutagenicity testing of butyraldehyde are mixed. Butyraldehyde was negative for mutation in 5 strains of Salmonella typhimurium with or without metabolic activation up to 10 mg/plate (HSDB 1994). Butyraldehyde was negative for sister chromatid exchange in human lymphocytes but positive in Chinese hamster ovary cells (<9 mg/mL) (Dynamac Corporation 1988). The chemical was negative for sex-linked recessive lethals in Drosophila melanogaster (Dynamac Corporation 1988). F. Developmental/Reproductive Toxicity Chromosomal and meiotic anomalies occurred during spermatogenesis in male mice receiving butyraldehyde by either intraperitoneal injection or the drinking water. No information was found on developmental/reproductive effects of butyraldehyde in humans. 1. Humans No information was found in the secondary sources searched regarding the developmental/reproductive toxicity of butyraldehyde to humans. 2. Animals Male mice were administered butyraldehyde either in a single intraperitoneal injection of 1 mg/animal or 30 mg/kg or in the drinking water at a concentration of 0.2 mg/L for 50 days (Dynamac Corporation 1988). By either route, chromosomal and meiotic anomalies were observed at all stages of spermatogenesis. G. Neurotoxicity Butyraldehyde causes anesthesia in rats at high levels following inhalation exposure. 1. Humans Due to the distinctive odor and the irritating properties of butyraldehyde, human exposure levels are unlikely to reach concentrations that might induce anesthesia. 2. Animals Anesthesia occurs in rats exposed by inhalation to high levels (not defined) (Brabec 1981). Dose-responsive reduction in amplitude and decreased conduction velocity were observed in the frog sciatic nerve over the concentration range of 0.01-1.0% butyraldehyde (HSDB 1994). V. ENVIRONMENTAL EFFECTS Butyraldehyde is moderately toxic to aquatic species; toxicity values are generally in the range of >1 mg/L to 100 mg/L. Butyraldehyde is not expected to be toxic to aquatic or terrestrial organisms at levels normally found in the environment. A. Toxicity to Aquatic Organisms LC50 values for aquatic organisms exposed to butyraldehyde for various durations are as follows: 25.8 mg/L for fathead minnow (Pimephales promelas; 96 hours), 114 and 57 mg/L golden orfe (Leuciscus idus; two different laboratories, 96 hours), 0.2% (2000 mg/L) for larvae of mosquito (Aedes aegypti; 4 hours) (Dynamac Corporation 1988). Minimum inhibitory concentrations of butyraldehyde for various organisms were as follows: 100 mg/L for Daphnia magna (based on swimming capability, 24 hours), 100 mg/L for bacterium (Pseudomonas putida; based on inhibition of cell multiplication, 24 hours), 4.2 mg/L for flagellate protozoan (Entosiphon sulcatum; cell growth, 48 or 72 hours), 98 mg/L for ciliate protozoan (Uronema parduczi; cell growth, 48 or 72 hours), and 83 mg/L for green alga (Scenedesmus quadricauda; inhibition of cell multiplication, 8 days) (Dynamac Corporation 1988). B. Toxicity to Terrestrial Organisms No information was found in the available literature for the toxicity of butyraldehyde in terrestrial species. The oral LD50 values of 2.5 to 5.9 g/kg in laboratory rats suggest that the chemical is acutely toxic to terrestrial animals in very high concentrations. C. Abiotic Effects Most butyraldehyde in the atmosphere is removed by reaction withy hydroxyl radicals (Dynamac Corporation 1988). According to the definition provided in the Federal Register (1992), butyraldehyde is a volatile organic carbon (VOC) substance. As a VOC butyraldehyde can contribute to the formation of photochemical smog in the presence of other volatile substances. VI. EPA/OTHER FEDERAL/OTHER GROUP ACTIVITY The Clean Air Act Amendments of 1990 list butyraldehyde as a hazardous air pollutant. Federal agencies and other groups (listed in Tables 5 and 6) can be contacted for additional information on butyraldehyde. TABLE 5. EPA OFFICES AND CONTACT NUMBERS FOR INFORMATION ON BUTYRALDEHYDE EPA Office Statute Contact Number ________________________________________________________________ Pollution Prevention PPAa (202) 260-1023 & Toxics EPCRA (313/TRI)b (800) 424-9346 TSCA (8A, 8D)c (800) 554-1404 Air Clean Air Act (919) 541-0888 ________________________________________________________________ aPPA: Pollution Prevention Act bEPCRA: Emergency Planning and Community Right to Know Act of 1986 cTSCA: Toxic Substances Control Act TABLE 6. OTHER FEDERAL OFFICES/CONTACT NUMBERS FOR INFORMATION ON BUTYRALDEHYDE Other Agency/Department/Group Contact Number ________________________________________________________________ American Industrial Hygiene Association (703) 849-8888 (AIHAWEELa: 25 ppm [72.5 mg/m3]) Consumer Product Safety Commission (301) 504-0994 Food & Drug Administration (301) 443-3170 ________________________________________________________________ aAIHAWEEL: American Industrial Hygiene Association Workplace Environmental Exposure Level; an 8-hour TWA (time-weighted-average) is for a normal 8-hour workday and a 40-hour workweek (AIHA 1994). VII. CITED REFERENCES AIHA. 1994 American Industrial Hygiene Association. Workplace Environmental Exposure Level. AIHA, Richmond, VA. Brabec MJ. 1981. Aldehydes and acetals. In: Patty's Industrial Hygiene and Toxicology, 3rd ed., Volume 2A. GD Clayton and FE Clayton, Eds. John Wiley & Sons, Inc., New York, NY, pp. 2632-2656. 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