Creosote oil, acenaphthene fraction

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

The scientific data base does not support classification of creosote oil, acenaphthene fraction, called wash oil (CAS No. 90640-84-9), as a PBT and vPvB substance although wash oil contains the decided PBT constituent anthracene (CAS no. 120-12-7) to approx. 0.3%.

The data show that the properties of the substance do not allow a direct comparison with all the criteria in Annex XIII, but nevertheless indicate that the substance does not have these properties.

Biodegradation:

Based on screening criteria, the 16 EPA-PAH taken as reference substances are not readily biodegradable, some of them are considered to be inherently biodegradable (2- and 3-ring aromatic compounds). Wash oil predominantly contains aromatic hydrocarbons with two condensed ring systems, and to a minor extent with three rings. Key constituents such as naphthalene, 1- and 2-methylnaphthalene, amounting to some 35 - 40% in wash oil, proved to be easily biodegradable in water in early studies according to OECD 301C [MITI(I)] and OECD 302C (MITI(II) (Yoshida et al. 1983). For several of these substances, biodegradation and half-lives in soil were determined. Evaluation of these results show that wash oil constituents can be biodegraded in soil. For wash oil as a whole, a half-life in soil of 109 days was estimated in a worst-case approach. In addition, a historical monitoring programme revealed that in particular anthracene was not accumulating over decades, while other higher PAHs tended to increase (Jones et al. 1989). Based on its half-life in soil (see above and under Chapter 4.1.2.2.), wash oil does not fulfil the P criterion of REACH Annex XIII. It is assessed not to be persistent.

Bioaccumulation:

Single PAHs which are constituents of wash oil show only low to moderate bioaccumulating potential, with reliable BCF values in fish generally below 2000.This can also assumed for anthracene. However, unfortunately this substance was omitted from a search and testing programme by CONCAWE (see Lampi and Parkerton 2009), because of its irreversible classification as PBT.Furthermore, there is evidence for the absence of a biomagnification potential for PAHs including anthracene (Lampi and Parkerton 2009) (WHO 2003). Therefore, wash oil is not considered to fulfil the B and vB criteria for PBT.

Toxicity:

Long-term toxicity data of wash oil (CAS No. 90640-84-9) are not available for the total mixture. Key components of wash oil were shown to produce chronic toxic effects in aquatic organisms at water concentrations only above the cut-off limit for the NOEC (10 µg/L).

Regarding health effects, wash oil is classified as Carc. 1B. In addition, it is self-classified as Muta. 2 and STOT Rep. Exp. 2 according to CLP regulation. Classifications identify the substance as fulfilling the toxicity criterion (T-).

References:

Lampi M and Parkerton T (2009). Bioaccumulation Assessment of PAHs, Review Paper Prepared for CONCAWE by ExxonMobil Biomedical Sciences, Inc., October 2009

WHO (2003). HEALTH RISKS OF PERSISTENT ORGANIC POLLUTANTS FROM LONG-RANGE TRANSBOUNDARY AIR POLLUTION, JOINT WHO/CONVENTION TASK FORCE ON THE HEALTH ASPECTS OF AIR POLLUTION. WHO Regional Office for Europe, World Health Organization 2003