Chemometric tools to evaluate the spatial distribution of trace metals in surface sediments of two Spanish rías

► Oil spillages represent a common problem in the European marine environment. ► Current European Directives imply tiered visual comparisons of chromatograms. ► Subjective decisions can be avoided with supervised pattern recognition to classify unknowns. ► Counterpropagation artificial neural networks outstood among five parametric and non parametric methods. ► Less than 5% false positives and negatives revealed the chemometric alternative as a powerful alternative.