Dibutyl phthalate (DBP) is an organic compound which is commonly used as a plasticizer because of its low toxicity and wide liquid range. With the chemical formulaC6H4(CO2C4H9)2, it is a colorless oil, although impurities often render commercial samples yellow.[3]
DBP is produced by the reaction of n-butanol with phthalic anhydride.[3] DBP is an important plasticizer that enhances the utility of some major engineering plastics, such as PVC. Such modified PVC is widely used in plumbing for carrying sewerage and other corrosive materials.[3]
Biodegradation by microorganisms represents one route for remediation of DBP. For example, Enterobacter species can biodegrade municipal solid waste—where the DBP concentration can be observed at 1500 ppm—with a half-life of 2–3 hours. In contrast, the same species can break down 100% of dimethyl phthalate after a span of six days.[6]
The white rot fungus Polyporus brumalis degrades DBP.[7]
DBP is leached from landfills.[8]
Physical properties relevant to biodegradation[edit]
As reflected by its octanol-water partition coefficient of around 4, it is lipophilic, which means that it is not readily mobilized (dissolved by) water. Nonetheless, dissolved organic compounds (DOC) increase its mobility in landfills.[9][10]
DBP has a low vapor pressure of 2.67 x 10−3 Pa. Thus DBP does not evaporate readily (hence its utility as a plasticizer).[11] The Henry's Law constant is 8.83 x 10−7 atm-m3/mol.[4]
The use of this substance in cosmetics, including nail polishes, is banned in the European Union under Directive 76/768/EEC 1976.[13]
The use of DBP has been restricted in the European Union for use in children's toys since 1999.[14]
An EU Risk Assessment has been conducted on DBP and the outcome has now been published in the EU Official Journal. To eliminate a potential risk to plants in the vicinity of processing sites and workers through inhalation, measures are to be taken within the framework of the IPPC Directive (96/61/EC) and the Occupational Exposure Directive (98/24/EC)[15] Also includes the 2004 addendum.
Dibutyl phthalate (DBP) is one of the six phthalic acid esters found on the Priority Pollutant List, which consists of pollutants regulated by the United States Environmental Protection Agency (U.S. EPA).[19]
DBP was added to the California Proposition 65 (1986) list of suspected teratogens in November 2006. It is a suspected endocrine disruptor.[12] It was used in many consumer products, e.g., nail polish, but such usages has declined since around 2006. It was banned in children's toys, in concentrations of 1000 ppm or greater, under section 108 of the Consumer Product Safety Improvement Act of 2008 (CPSIA).
^ abcdPeter M. Lorz, Friedrich K. Towae, Walter Enke, Rudolf Jäckh, Naresh Bhargava, Wolfgang Hillesheim "Phthalic Acid and Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry, 2007, Wiley-VCH, Weinheim. doi:10.1002/14356007.a20_181.pub2
^ abHuang, Jingyu; Nkrumah, Philip N.; Li, Yi; Appiah-Sefah, Gloria (2013). Reviews of Environmental Contamination and Toxicology Volume 224. Reviews of Environmental Contamination and Toxicology. Vol. 224. Springer, New York, NY. pp. 39–52. doi:10.1007/978-1-4614-5882-1_2. ISBN9781461458814. PMID23232918.
^Hu Y, Dong C, Chen M, Chen Y, Gu A, Xia Y, Sun H, Li Z, Wang Y (August 2015). "Effects of monobutyl phthalate on steroidogenesis through steroidogenic acute regulatory protein regulated by transcription factors in mouse Leydig tumor cells". J Endocrinol Invest. 38 (8): 875–84. doi:10.1007/s40618-015-0279-6. PMID25903692. S2CID21965989.
^Abdel daiem, Mahmoud M.; Rivera-Utrilla, José; Ocampo-Pérez, Raúl; Méndez-Díaz, José D.; Sánchez-Polo, Manuel (2012). "Environmental impact of phthalic acid esters and their removal from water and sediments by different technologies – A review". Journal of Environmental Management. 109: 164–178. doi:10.1016/j.jenvman.2012.05.014. PMID22796723.
^Bauer, M.J.; Herrmann, R. (2 July 2016). "Dissolved organic carbon as the main carrier of phthalic acid esters in municipal landfill leachates". Waste Management & Research. 16 (5): 446–454. doi:10.1177/0734242x9801600507. S2CID98236129.
^Donovan, Stephen F. (1996). "New method for estimating vapor pressure by the use of gas chromatography". Journal of Chromatography A. 749 (1–2): 123–129. doi:10.1016/0021-9673(96)00418-9.
^Gao, Da-Wen; Wen, Zhi-Dan (2016). "Phthalate esters in the environment: A critical review of their occurrence, biodegradation, and removal during wastewater treatment processes". Science of the Total Environment. 541: 986–1001. Bibcode:2016ScTEn.541..986G. doi:10.1016/j.scitotenv.2015.09.148. PMID26473701.
