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EC number: 201-557-4
CAS number: 84-74-2
DBP may be released into the environment
during its production and subsequent life cycle stages, including
disposal. Emissions to water and air are expected to be the most
important entry routes of DBP. General characteristics of DBP which are
relevant for the exposure assessment are given below.
The contribution of hydrolysis to the
overall environmental degradation of phthalate esters, including DBP, is
expected to be low. Photo-oxidation by OH radicals contributes to the
elimination of DBP from the atmosphere. An atmospheric half-life of
about 1.8 days has been estimated for the photo-oxidation reaction. The
metabolic pathway of aerobic and anaerobic biodegradation of phthalates
can be summarised as follows. First the di-ester is hydrolysed into the
mono-ester by esterases with low substrate specificity. Subsequently the
mono-ester is converted into phthalic acid. There is ample evidence that
DBP is ready biodegradable under aerobic conditions. The same literature
sources indicate that biodegradation of DBP is much slower in the
anaerobic environment, e.g. sediments or deeper soil or groundwater
The Henry's law constant of 0.27 Pa.m3/mol
indicates that DBP will only slowly volatilize from surface waters, i.e.
virtually all of the DBP will remain in the water phase at equilibrium.
The octanol/water partition coefficient (Kow) of DBP is high and
consequently the equilibrium between water and organic carbon in soil or
sediment will be very much in favour of the soil or sediment. A Koc of
6,340 l/kg can be calculated using the log Kow of 4.57. Despite its low
volatility, DBP has been reported as particulate and as a vapour in the
atmosphere. In the air DBP is transported and removed by both wet and
The high Kow of DBP indicates that the
substance has a potential for bioaccumulation. However, the actual
degree of bioaccumulation in vivo will be determined by the
metabolisation and the elimination rate of the substance. The available
BCF data demonstrate a relatively low bioconcentration, but also
indicate that higher BCF values are obtained when the BCF is calculated
for the total amount of metabolites using 14C-labelled material. The
experimental BCF of 1.8 l/kg for DBP from the recent study is used in
the further risk assessment for secondary poisoning (aquatic route). In
the risk characterisation attention will be paid to the possible
consequences of using a higher value. No
experimental BCF data are available for terrestrial species. EUSES
calculates a BCF worm of 13 kg/kg.
European Union Risk Assessment Report
dibutyl phthalate, Volume 29, p. 6 (2003)
Editors: B. G. Hansen, S.J. Munn, R.
A/Ianou, F. Berthault, J. de Bruin, M. Luotamo, C. Musset, S. Pakalin,
G. Pellegrini, S. Scheen S. Vegro.
Office for Official Publications of the
European Communities, ISBN 92—894—1276—3
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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