Hydrocarbon space mapping to support gas oil read-across for human health hazard assessment

As vertebrate animal studies form the basis for assessing certain human health and ecotoxicity hazards under the EU (European Union) REACH regulation, appropriate alternative approaches to fulfil information requirements must be considered in order to avoid unnecessary animal studies in testing each substance. Read-across is a commonly used approach, justifiable only with robust evidence of structural similarity. From their manufacturing process, petroleum substances constitute a continuum of hydrocarbons; however, the precise identity and composition of every constituent is, for most petroleum substances, unknown and the composition may vary across samples of the same substance.

Read-across justification in accordance with the REACH requirements for these substances is therefore challenging. This article sets out the development and application of a hydrocarbon space mapping approach for gas oils based on comprehensive two-dimensional gas chromatography, which in combination with biological response and lower-tier hazard data can be used for the selection of a minimum number of representative samples for higher-tier vertebrate testing.