Oil reaching the coast: Is Brazil on the route of international oceanic dumping?

After the oil spill disaster occurred in 2019, various events of tar balls reaching the Brazilian coast and archipelagos have been reported. The hypothesis here is that the oil/waste dumped in international waters by ships on-route to Cape of Good Hope is reaching the Brazilian coast. On that account, 30-year probabilistic simulations were used to estimate the probability of dumped oil residue reaching the Brazilian coast. The simulations considered three Zones following the South Atlantic route. The results have shown that up to 28.5 % of large ships could dump oil on-route. Inside the Brazilian Exclusive Economic Zone, the probability of dumped oil/waste reaching the coastline is about 62 % and quickly decreases for Dumping Zones 2 and 3. Equatorial and Northeast shores of Brazil are the most vulnerable to oceanic dumping when compared to other regions.

Mysterious oil spill on the Brazilian coast - Part 2: A probabilistic approach to fill gaps of uncertainties.

Over 5000 tons of spilled oil reached the northeast coast of Brazil in 2019. The Laboratory for Computational Methods in Engineering (LAMCE/COPPE/UFRJ) employed time-reverse modeling and identify multiple potential source areas. As time-reverse modeling has many uncertainties, this article carried out a methodology study to mitigate them. A probabilistic modeling using Monte Carlo approach was developed to test these source areas with the Spill, Transport, and Fate Model (STFM) and a scenario tree methodology was used to select possible spill scenarios. To estimate the performance of Lagrangian models, two new model performance evaluations were added to Chang and Hanna (2004). The combination of probabilistic simulations, scenario tree analysis, and model performance evaluation proved to be a powerful tool for mitigating the uncertainties of time-reverse modeling, yielding good results and simple implementation.

Mysterious oil spill on Brazilian coast: Analysis and estimates.

In 2019-2020, a mysterious oil spill reached a large part of the Brazilian coast. In order to contribute to the clarification part of these mysteries involving this accident, the present study aims to estimate the initial volume spilled using the STFM (Spill, Transport and Fate Model). We started from the hypothesis that the leak was caused by tanker buoyancy problems (hull rupture or engine failure), resulting in slow loss of part of its cargo (leaking or dumping) in the subsurface waters. The estimated volume (5000-12,500 m3) was similar to that expected in a continuous leak from an internal compartment tanker with the size between PANAMAX and SUEZMAX. This volume may have been the largest oil spill on the Brazilian coast since 2004, and it caused institutional and socioeconomic crisis because of the poor management of public resources.