Global Journal of Science Frontier Research, H: Environment & Earth Science, Volume 22 Issue 5

Eichler P.P.B. ɲ , Ferreira A.L. ʍ , Barker C.P. ʌ , Gomes M. P. & Vital H ൿ Abstract - The worst environmental oil spill disaster ever recorded in any tropical coastal region globally happened in 2019; severely affecting one of Brazil most famous northeast tourist area South Pirangi Reef area in the state of Rio Grande do Norte (RN). The oil, a complex chemical mixture of hydrocarbon including heavy metals spilled on beaches, in estuaries, and reefs has spread between 50 cm and 1 m deep, occasionally sinking to the benthos. Death of oiled animals and Habitat destruction are acute and long-term consequences on ecological systems that rely on the now impacted environment for survival. Pirangi Reef which was subjected to the oil spill in October 2019, was previously studied in 2013 and 2014 with no spotting of oil patches in the 55 sediment or water samples at that time. After the oil spill, 25 new sites in the reef areas, sandy sediments and macroalgae substratum were sampled to compare temporal data after the disastrous event. Our findings show that more than 95% of the unconsolidated sediment samples, including some corals, had some evidence of oil in 2019 opposed to no evidence at all in 2013 and 2014. Data on benthic foraminiferal fauna show loss of 26 species including symbiotic species. We observe that 44 foraminiferal species were found in 2013 and 2014, and in 2019 after the oil spill, only 20 species survived the effects of the accident, which includes loss of habitat and dissolution by the resulting acidic sediment contaminants. In addition, we observe that 59% of all species did not tolerate the new environment and have disappeared, whereas 50% of the symbiotic species were also extinct. This decrease in number among benthic species after the oil spill (2019) shows that the scope of contamination is much farther beyond what was previously assumed. Keywords: environmental disaster, crude oil, foraminifera, coral reef, baren zone, river. I. I ntroduction he worldwide production of crude oil and natural gas is at the peak, with an estimated worldwide production of 97 million barrels per day in 2020. Approximately half of this amount is transported by sea. As follows, worldwide marine coastal areas are exposed to the oil spills occurring as a result of accidents or illegal practices. Therefore, crude oil is already Author ɲ ʍ ʌ ළ͗ Graduate Program in Geodynamics and Geophysics (PPGG), Laboratory of Marine Geology and Geophysics and Environmental Monitoring, Federal University of Rio Grande do Norte (UFRN), University Campos, Lagoa Nova, Natal, RN, Brazil. www.EcoLogicProject.com , was22was22@yahoo.com , e-mails: patriciaeichler@gmail.com , andressalimaferreira@ufrn.edu.br, gomesmp@geologia.ufrn.br , helenicevital2004@yahoo.com widespread primarily in marine sediments close to harbors and marinas, and oil spills alter the oil’s chemical composition because it allows the breakdown of oil components. The release of thousands of tons of petroleum hydrocarbons (PHs) affects the marine environment and causes severe ecological and economical damage and can cause ocean acidification. The oil spill releases H 2 S (hydrogen sulfide), ammonia and methane, causing the decrease in pH of the sediment and the decrease in the dissolved oxygen concentration in the water. Marine ecosystems are already subject to touristic activities and sewage pollution, and this unprecedented oil spill in 2019, declined biodiversity in the modern anthropogenic era. The evaluation of the damage for the local coastal communities and future generations, and the environmental quality of the marine and coastal region are in need of action. The continuous dissolution of benthic calcareous organisms will culminate with the total disappearance of microfauna at least one year after the accident, similar to what had been showed in Guanabara Bay, Rio de Janeiro, Brazil (Eichler et al., 2014). Dealing effectively with these impacts includes understanding how pollutants and contaminants in general are released and how they behave in the environment (Cedre, 2007). Hydrocarbon petroleum products are very reactive in aerobic environments via microbial and photochemical reactions (Varjani, 2017; Atlas & Hazen, 2011; Salminen et al.,2004; Widdel & Rabus, 2001), and the production of hydrogen sulphide (H 2 S) is a result of the microbial breakdown of organic materials of crude oil in the absence of oxygen. Hydrogen sulphide is a gas without color, and is inflammable, poisonous and corrosive, noticeable by its rotten egg smell and with toxicity similar to carbon monoxide prevents cellular respiration. Monitoring and early detection of H 2 S could mean the difference between life and death. The contamination impact in the medium and long term is a silent one caused by oil being partially degraded and absorbed by the environment. Concentrations of PAHs sufficient to affect individual health following oil spills are common and can remain for long periods in some habitats (Cherr et al 2017, Oros et al 2007). The polycyclic aromatic hydrocarbons (PAHs) present in oil are an immunotoxin to several wild aquatic species. While the origin of the oil T 1 Global Journal of Science Frontier Research Volume XXII Issue V Year 2022 49 ( H ) Version I © 2022 Global Journals Evidence of Sediment Sterility and Benthic Quality as Deleterious Consequences after the 2019 Oil Spill in Northeastern Brazil