# Multilayered Forensic Protocol Based on In-Depth Mass Spectrometry Techniques for the Investigation of Suspicious Drums of Oils with the 2019–2022 Brazilian Oil Spill Disaster

## TL;DR

This paper presents a forensic protocol using mass spectrometry to determine if oil from suspicious drums was linked to a major 2019–2022 Brazilian oil spill.

## Contribution

A novel multilayered protocol combining mass spectrometry and statistical analysis is introduced for forensic oil spill investigations.

## Key findings

- Oil from the drums is not similar to oils from the Sergipe–Alagoas basin.
- The spilled oils were confirmed to originate from the same event using biomarkers and trace elements.
- UHR MS and PCA/HCA analyses helped establish definitive similarity relationships between samples.

## Abstract

In 2019, the northeast coast of Brazil experienced the
country’s
largest environmental disaster involving a mysterious oil spill. At
the same time, two drums containing an oily substance were found ashore
on the coasts of Sergipe and Rio Grande do Norte. Since oil spills
are often unavoidable, it was necessary to assess the possibility
of simultaneous spills. In this context, a new multilayered protocol
is proposed in this work to determine the similarity or dissimilarity
between the oily substance in the drums and the suspected samples.
Due to geographic proximity, samples from the Sergipe–Alagoas
basin were also included as suspects, alongside samples collected
from the oil spill. Data obtained from reconstructed-ion chromatograms
using m/z 85 and m/z 192, as well as hopane and sterane biomarkers
analyzed by gas chromatography-based techniques, trace elements determined
by energy-dispersive X-ray analysis (EDX), and ultrahigh-resolution
mass spectrometry (UHR MS) data, confirmed that the spilled oils originated
from the same event. Furthermore, UHR MS, as an additional analytical
layer, helped definitively establish the similarity or dissimilarity
relationships between the sample sets when analyzed through principal
component analysis (PCA) and hierarchical clustering analysis (HCA).
These results suggest that the oil from the drums does not share similarities
with oils produced in the Sergipe–Alagoas basin. However, it
does show similarities to mysterious oils found on Brazilian northeast
beaches in 2019.