Naphtha (petroleum), light straight-run, co-processed with hydrocarbons derived from thermally cracked waste plastics

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Substance is a hydrocarbon UVCB. Tests for biodegradation in water are designed for use with single chemical substances and results used for classification. For the purpose of risk assessment, this endpoint is characterized using quantitative structure property relationships for representative hydrocarbon structures that comprise the hydrocarbon blocks. The environmental risk of this substance is assessed using the PETRORISK model (see Product Library in PETRORISK spreadsheet attached to IUCLID Section 13).

Gasoline naphtha fractions are not readily biodegradable but are considered inherently biodegradable. In a report on environmental classification (Concawe 2001), it was concluded that, based on the known properties of individual hydrocarbons in the range C4 to C11, gasoline naphtha fractions are not readily biodegradable, but are regarded as being inherently biodegradable, since they can be degraded by micro-organisms. This is supported by two research bidegradation studies with gasoline samples that show a clear potential to degrade in the environment. In a further investigation (Concawe 2012) on PBT evaluation of petroleum substances CONCAWE developed QSAR estimates (BioHCwin) and reviewed existing data for individual hydrocarbons representative of the various ‘hydrocarbon blocks’ covering a range of petroleum substances, including gasoline naphthas. Using the Hydrocarbon Block method and data on biodegradation of representative hydrocarbons in the range C4 to C11, it is concluded that gasoline naphtha fractions do not meet the persistence criteria and can be regarded as being inherently biodegradable.

Concawe 2001:Environmental classification of petroleum substances - summary data and rational. Report No 01/54. Concawe Brussels.

Concawe 2012:An evaluation of the Persistence, Bioaccumulation and Toxicity of Petroleum Hydrocarbons (revised), May 2012

The material is a complex UVCB substance that comprises a large number of individual hydrocarbon constituents. These constituents exhibit different properties relevant to environmental risk assessment. Consistent with REACH technical guidance and Annex VIII criteria, the PBT assessment was undertaken using the hydrocarbon block method. Measured data and model predictions were evaluated for representative structures of the hydrocarbon blocks covering the diesel fuel/gas oil range. Further details can be found in dossier Section 13.

Results of the analysis show that none of the representative hydrocarbon structures present in the gasoline naphtha range (carbon number C4 -C11) range meet the vPvB or PB criteria. Hence the material is not considered a vPvB or PB.

The material does however meet the T criteria as it is classified carcinogenic Category 1A, Mutagenic Category 1B and Reprotoxic Category 2 (CLP Regulation EC 1272/2008), based on concentrations of benzene, toluene and n-hexane present, that exceed the classification thresholds.