The impact of chronic and acute problems on sea turtles: The consequences of the oil spill and ingestion of anthropogenic debris on the tropical semi-arid coast of Ceará, Brazil.

Sea turtle mortality is often related to materials that reach the coast from different anthropic activities worldwide. This study aimed to investigate whether sea turtle mortality was related to older marine problems, such as solid waste, or one of the largest oil spill accidents on the Brazilian coast, that occurred in 2019. We posed three questions: 1) Are there solid residues in the digestive tract samples, and which typology is the most abundant? 2) Can meso­ and macro-waste marine pollutants cause mortality? 3) Is the dark material found really oil? A total of 25 gastrointestinal content (GC) samples were obtained, of which 22 ingested waste of anthropogenic origin and 18 were necropsied. These 22 samples were obtained during or after the 2019 oil spill, of which 17 specimens were affected, making it possible to suggest oil ingestion with the cause of death in the animals that could be necropsied. Macroscopic data showed that the most abundant solid waste was plastic (76.05 %), followed by fabrics (12.18 %) and oil-like materials. However, chemical data confirmed only three specimens with oil levels ranging from remnants to high. It was possible to infer possible causes of death in 16 of the total 18 necropsied cases: Most deaths were due to respiratory arrest (62.5 %), followed by pulmonary edema (12.5 %), cachexia syndrome (12.5 %), circulatory shock (6.25 %), and head trauma (6.25 %), which may have been caused by contact with solid waste, oil, or both. The study showed that not all dark material found in the GCs of turtles killed in oiled areas is truly oil, and in this sense, a chemical analysis step to prove the evidence of oil must be added to international protocols.

Tarballs on the Brazilian coast in late 2022 sustain Lepas anatifera Linnaeus, 1758 (Crustacea: Cirripedia): Occurrence and risk of petroleum hydrocarbon ingestion.

Since the 2019 oil spill on the northeastern coast of Brazil, oil materials have washed up on the beaches. A characteristic of the recent oil spill that began in late August was that some of the oiled material, such as tarballs, contained the goose barnacle species Lepas anatifera (Cirripedia, Lepadomorpha), which is well-known for its cosmopolitan distribution and wide occurrence in the oceans. The findings of this study provide information on the occurrence and contamination of petroleum hydrocarbons in animals adhered to the surfaces of tarballs sampled from beaches in the Brazilian states of Ceará and Rio Grande do Norte, between September and November 2022. The size of the barnacles varied from 0.122 to 2.20 cm, suggesting that the tarballs had been floating in the ocean for at least a month. All groups of L. anatifera collected from the tarballs had polycyclic aromatic hydrocarbons (PAHs) present (∑21PAHs from 476.33 to 3816.53 ng g-1). In comparison to high-molecular-weight PAHs, which are primarily from pyrolytic sources, low-molecular-weight PAHs, such as naphthalene and phenanthrene, which are mostly related to petrogenic sources, were shown to be more abundant. In addition, dibenzothiophene, which is exclusive of petrogenic origin, was found in all samples (30.74-537.76 ng g-1). The aliphatic hydrocarbons (AHs): n-alkanes, pristane, and phytane were also found and displayed petroleum characteristics. These results highlight the danger of increasing the absorption of petrogenic PAHs and AHs by organisms that use tarballs as substrates. L. anatifera is a crucial component of the food chain because many animals such as crabs, starfish, and gastropods consume it.

Weathering impacts on petroleum biomarker, aromatic, and polar compounds in the spilled oil at the northeast coast of Brazil over time.

After the wide oil spill reached the northeast of Brazil, the resurgence of oil was recorded and to evaluate this oil in detail, two samples collected in the state of Pernambuco in 2019 and 2021 were submitted to multiple analytical techniques. For both, we have found similar saturated biomarkers and triaromatic steroid ratios, implying that they are from the same spilled source. The n-alkanes, isoprenoids, and cycloalkanes were almost completely degraded due to evaporation, photooxidation, and/or biodegradation processes. The preferential loss of less alkylated PAHs than the more alkylated ones suggests that biodegradation was the most active process. This hypothesis is reinforced by the formation of mono and dicarboxylic acids assessed by GC × GC-TOFMS and ESI(-) FT-ICR MS high-resolution techniques. Furthermore, based on the ESI(-) FT-ICR MS results, three new ratios were proposed to evaluate the progress of the biodegradation process over time: Ox>2/O, SOx/SO, and SOx/N.

Implications of microbial enhanced oil recovery and waterflooding for geochemical interpretation of recovered oils.

Biosurfactants and waterflooding have been widely reported thus far for enhancing oil production. Nevertheless, there is a lack of literature to explore enhanced oil recovered methods effects on its chemical composition. The aim of this work is to investigate the effects of a biosurfactant produced by Bacillus safensis and brine injection on the recovered petroleum composition, and their implications for geochemical interpretation. Original and oils recovered from displacement tests were analyzed by gas chromatography and ultra-high-resolution mass spectrometry, emphasizing saturated and aromatic biomarkers and basic and acidic polar compounds. Geochemical parameters based on some saturated compounds were subtly affected by the recovery methods, showing their reliable applicability in geochemical studies. Contrarily, parameters based on some aromatic compounds were more affected by biosurfactant flooding, mostly the low molecular weight compounds. Thus, these aromatic parameters should be applied with caution after such methods. The distribution of basic and acidic polar compounds can also be modified affecting the geochemical interpretation. In the case of the basic ones, the biosurfactant greatly influenced the N class species with favorable loss of lower aromaticity compounds. In addition to water solubilization, the compositional changes described in this study can be related to fractionation due to adsorption on reservoir rocks.

Is there a similarity between the 2019 and 2022 oil spills that occurred on the coast of Ceará (Northeast Brazil)? An analysis based on forensic environmental geochemistry.

The main objective of this study was to investigate the 2019 and 2022 oil spill events that occurred off the coast of the State of Ceará, Northeastern Brazil. To further assess these mysterious oil spills, we investigated whether the oils stranded on the beaches of Ceará in 2019 and 2022 had the same origin, whether their compositional differences were due to weathering processes, and whether the materials from both were natural or industrially processed. We collected oil samples in October 2019 and January 2022, soon after their appearance on the beaches. We applied a forensic environmental geochemistry approach using both one-dimensional and two-dimensional gas chromatography to assess chemical composition. The collected material had characteristics of crude oil and not refined oils. In addition, the 2022 oil samples collected over 130 km of the east coast of Ceará had a similar chemical profile and were thus considered to originate from the same source. However, these oils had distinct biomarker profiles compared to those of the 2019 oils, including resistant terpanes and triaromatic steranes, thus excluding the hypothesis that the oil that reached the coast of Ceará in January 2022 is related to the tragedy that occurred in 2019. From a geochemical perspective, the oil released in 2019 is more thermally mature than that released in 2022, with both having source rocks with distinct types of organic matter and depositional environments. As the coast of Ceará has vast ecological diversity and Marine Protected Areas, the possibility of occasional oil spills in the area causing severe environmental pollution should be investigated from multiple perspectives, including forensic environmental geochemistry.

Monitoring chemical compositional changes of simulated spilled Brazilian oils under tropical climate conditions by multiple analytical techniques.

To comprehensively understand the chemical changes over time of spilled oils subject to tropical climate conditions and the active weathering processes, a spill simulation experiment was conducted along 210 days with two distinct Brazilian oils (19 and 24 API) under irradiation and non-irradiation of sunlight. Isoprenoids and n-alkanes showed a great loss after 40 days for both oils under the two conditions due to evaporation. Diagnostic ratios of saturated biomarkers showed no changes, whereas the polycyclic aromatic hydrocarbons had a decreasing concentration under both conditions mainly due to evaporation. Furthermore, oxygenated polar compounds produced by photooxidation were investigated by ESI(-) FT-ICR MS and showed changes only for the oils exposed to sunlight irradiation. Based on the observed polar compositional changes, new parameters are suggested using heteroatom classes to estimate oil spill time under tropical conditions: NO3/NO2; NO3/(NO + NO2); ∑NOx/N1; (O4 + O3)/(O2 + O1); O4/(O2 + O1); and O3/O2.

Assessing raw materials as potential adsorbents to remove acidic compounds from Brazilian crude oils by ESI (-) FT-ICR MS.

The presence of acidic compounds as naphthenic acids in crude oil causes several problems for the petroleum industry, including corrosion in both upstream and downstream production processes. Based on this scenario, the main objective of this work was to investigate the removal of the acidic compound from two Brazilian heavy oils by adsorption processes using six potential adsorbents: powdered shale, activated carbon, bentonite, silica gel, powdered sandstone and powdered wood. These raw materials were previously characterized by conventional and surface analysis techniques, which show that they offer a good surface area and thermal stability. To evaluate the removal efficiency at the molecular level, the crude oil samples and the filtered oils were analyzed by negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry [ESI (-) FTICR MS]. The O2 class, which is related to the relatively high acidity of the samples, was the most abundant in both crude oil samples, moreover, this class was more retained by adsorbents. Silica gel, activated carbon and bentonite were the best adsorbents of acidic compounds from the tested oils, in agreement with their markedly higher surface area and porous volume. Additionally, a chromatographic analysis was performed and showed no changes in the oil profile.