Forensic environmental geochemistry to reveal the extent, characteristics, and fate of waxy tarballs spilled over the northeast coast of Brazil in 2022

Abstract

This work applied the forensic environmental geochemistry assessment to evaluate the tarballs that contaminated the coast of Brazil in late 2022. Accordingly, saturated and aromatic biomarkers were analyzed by gas chromatography and acidic polar compounds by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) of 16 tarball samples from beaches of five Brazilian states. All samples presented waxy characteristics and are from the same source, highlighting the large coast extension affected by this event (∼3,000 km). However, they have distinct sources from the spilled oils stranded on the Brazilian coast in 2019 and early 2022, as they present distinct fingerprints related to the distribution of resistant biomarkers, including the triaromatic steroids, tricyclic and pentacyclic terpanes, and steranes, which mirrors in significantly different diagnostic ratios. Biomarkers indicate their characteristics of mature and marine crude oils (not fuel). Furthermore, all samples presented low weathering levels, indicating their fate as a high-persistence contaminant in the environment. These tarballs likely originated from the washing processes of ship tanks and persisted drifting on the sea until they arrived on the Brazilian coast.