Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Creosote oil, acenaphthene fraction (wash oil) is a liquid organic UVCB substance which cannot be tested for ready biodegradability under standard test conditions. The complex mixture consists of 2- and 3-ring aromatic compounds from naphthalene to phenanthrene, naphthalene, methylnaphthalenes, and acenaphthene amounting to about 50 %.

Individual substances are known to be resistant to ready biodegradation to large extent (see above). Some are expected to be inherently biodegradable. Conflicting results are reported for naphthalene: While not biodegradable in a MITI(II) test (= OECD 302C) (NITE 1979), it proved to be readily biodegradable in a different ready test [MITI(I) = OECD 301C] (Yoshida et al. 1983). The same group found easy biodegradation also for 1- and 2-methylnaphthalene in a MITI(II) test (= OECD 302C).

In a biodegradation study in soil, half-lives of several key constituents of wash oil were determined to be in the range between ca. 2 and 50 days. This demonstrates that wash oil even if not being readily biodegradable can be biodegraded in the environment.