Oil impact on the environment and aquatic organisms on the coasts of the states of Alagoas and Sergipe, Brazil - A preliminary evaluation

Offshore oil spills in Brazil: An extensive review and further development

The present study offers an extensive overview on the evolution and current state of marine oil spill research in Brazil and then discusses further directions. Given the historical and current relevance of this issue, this paper also aims to summarize the exploration, geological background, design of oil spills timeline and assessment of the most important of them. Moreover, it includes a critical comparison of Brazilian oil spill models in terms of their simulation abilities, real-time field data assimilation, space and time forecasts and uncertainty evaluation. This study also presents the perspectives of the Multi-User System for Detection, Prediction, and Monitoring of Oil Spills at Sea (SisMOM) the largest and most important Brazilian project to face the offshore oil spills.

Bioaccumulation of chemical elements in fish from areas affected by oil on the coast of Bahia, Brazil

In 2019, the Brazilian coast was affected by the largest oil spill in its history. We assessed the levels of chemical elements in Lutjanus synagris and Haemulon aurolienatum fish from Itacaré (least affected area), Tinharé-Boipeba (most affected area) and Madre de Deus (chronically affected area). The level of metals differed between species, tissues, life cycle phases, maturation stages and between sampled locations, indicating the influence of biological and environmental aspects on bioaccumulation. Only fish in Madre de Deus showed lead contamination, while arsenic concentrations in the three areas exceeded the maximum value acceptable by Anvisa (National Health Surveillance Agency). It is suggested that the oil spill may have impacted species differently, also having an impact in fish from less affected areas. However, metal concentrations in fish in Madre de Deus stood out when compared to populations in other studied areas.

Finding the needle in a haystack: Evaluation of ecotoxicological effects along the continental shelf break during the Brazilian mysterious oil spill

Oceanic oil spills present significant ecological risks that have the potential to contaminate extensive areas, including coastal regions. The occurrence of the 2019 oil spill event in Brazil resulted in over 3000 km of contaminated beaches and shorelines. While assessing the impact on benthic and beach ecosystems is relatively straightforward due to direct accessibility, evaluating the ecotoxicological effects of open ocean oil spills on the pelagic community is a complex task. Difficulties are associated with the logistical challenges of responding promptly and, in case of the Brazilian mysterious oil spill, to the subsurface propagation of the oil that impeded remote visual detection. An oceanographic expedition was conducted in order to detect and evaluate the impact of this oil spill event along the north-eastern Brazilian continental shelf. The pursuit of dissolved and dispersed oil compounds was accomplished by standard oceanographic methods including seawater polycyclic aromatic hydrocarbons (PAHs) analysis, biomass stable carbon isotope (δ13C), particulate organic carbon to particulate organic nitrogen (POC:PON) ratios, nutrient analysis and ecotoxicological bioassays using the naupliar phase of the copepod Tisbe biminiensis. Significant ecotoxicological effects, reducing naupliar development by 20-40 %, were indicated to be caused by the presence of dispersed oil in the open ocean. The heterogeneous distribution of oil droplets aggravated the direct detection and biochemical indicators for oil are presented and discussed. Our findings serve as a case study for identifying and tracing subsurface propagation of oil, demonstrating the feasibility of utilizing standard oceanographic and ecotoxicological methods to assess the impacts of oil spill events in the open ocean. Ultimately, it encourages the establishment of appropriate measures and responses regarding the liability and regulation of entities to be held accountable for oil spills in the marine environment.

Polycyclic aromatic hydrocarbons in seawater after the mysterious oil spill of 2019 on the Pernambuco coast, northeast Brazil

In 2019, one of Brazil's most significant environmental disasters occurred, involving an oil spill that directly affected Pernambuco state. Contamination along the coast was evaluated by the quantification of polycyclic aromatic hydrocarbons (PAHs) in fifty seawater samples collected in the summer and winter of 2021. Analysis using fluorescence spectroscopy revealed that for all the samples, levels of dissolved/dispersed petroleum hydrocarbons (DDPHs) were higher than the regional baseline for tropical western shores of the Atlantic Ocean. GC-MS analyses quantified 17 PAHs in the samples, with highest total PAHs concentrations of 234 ng L-1 in summer and 33.3 ng L-1 in winter, which were consistent with the highest risks observed in ecotoxicity assays. The use of diagnostic ratios showed that the coast was impacted by a mixture of PAHs from petrogenic and pyrolytic sources. The results indicated the need for continuous monitoring of the regions affected by the 2019 spill.

Unraveling the spectral and biochemical response of mangroves to oil spills and biotic stressors

Mangroves are prone to biotic and abiotic stressors of natural and anthropogenic origin, of which oil pollution is one of the most harmful. Yet the response of mangrove species to acute and chronic oil exposure, as well as to other stressors, remains barely documented. In this study, a non-destructive, non-invasive approach based on field spectroscopy is proposed to unravel these responses. The approach relies on tracking alterations in foliar traits (pigments, sugars, phenols, and specific leaf area) from reflectance data in the 400-2400 nm spectral range. Three mangrove species hit by two of the most notorious oil spills in Brazilian history (1983 and 2019) and various biotic stressors, including grazing, parasitism, and fungal disease, were investigated through field spectroscopy and machine learning. This study reveals strong intra- and interspecific variability of mangrove's spectral and biochemical responses to oil pollution. Trees undergoing acute exposure to oil showed stronger alterations of foliar traits than the chronically exposed ones. Alterations induced by biotic stressors such as parasitism, disease, and grazing were successfully discriminated from those of oil for all species based on Linear Discriminant Analysis (Overall Accuracy ≥76.40% and Kappa ≥0.70). Leaf chlorophyll, phenol, and starch contents were identified as the most relevant traits in stressor discrimination. The study highlights that oil spills affect mangroves uniquely, both acutely and chronically, threatening their global conservation.

Development of a green and low-cost method to determine mercury content in sediments affected by oil spill on the Brazilian coast

Tons of crude oil were found on the Brazilian coast in 2019, and studies assessing its chemical composition are still scarce. This study aimed to develop a new and simple technique of cold vapor generation using infrared irradiation coupled with atomic absorption spectrometry to determine mercury content in sediments contaminated by crude oil. Experimental conditions were evaluated, including formic acid concentration, reactor temperature, and carrier gas flow rate. The accuracy of the method was validated by comparison with mercury contents in a certified reference material (PACS-2). The detection limit was found to be 0.44 μg kg-1. The developed method was applied to determine the total mercury content in marine sediment samples collected from beaches in Ceará State. Mercury concentrations ranged from 0.41 to 0.95 mg kg-1. The proposed method is efficient, simple, low-cost, and adequate for its purpose.

Metal and metalloid maternal transfer in a newborn West Indian manatee (Trichechus manatus) two years after the northeastern oil spill disaster of 2019 in Brazil

A large-scale oil spill along the northeastern Brazilian coast in 2019-2020 severely impacted primary manatee habitats in Brazil. This study aimed to assess metal and metalloid contamination in a dead manatee calf found following this oil spill. Several elements were detected, including chromium, iron, nickel, lead, and vanadium, which are crude oil components, and thallium, a component of dispersants used to degrade and dissipate crude oil. The presence of these contaminants in the manatee calf is indicative of maternal exposure, metabolism, and newborn transference via placenta and lactation. This is the first report of mother-calf metal transfer in manatees, highlighting the species' vulnerability and potential long-term population dynamics effects, and the first report for several metals and metalloids in these animals, laying the foundation for future research efforts. These findings highlight the urgent need for continued environmental monitoring, ecotoxicological assessments, and conservation initiatives.

Classification of produced water samples using class-oriented chemometrics and comprehensive two-dimensional gas chromatography coupled to mass spectrometry

Produced water (PW) is a type of wastewater that arises during oil and gas production. Due to its potential environmental impact, PW is one of the most closely monitored forms of wastewater in the petroleum industry. The total oil and grease (TOG) content in the water is a crucial parameter for assessing the environmental impact of PW. Traditional methods for analyzing TOG in PW can be time-consuming and may not be compatible with green chemistry principles. In this study, an alternative method for classifying PW samples is proposed using a one-class classifier (OCC) model, which has proven useful for classification problems. To achieve this goal, headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography (GC×GC) were employed to obtain TOG profiles from PW. A series of simulated PW samples containing TOG were generated using a mixture design comprising four petrochemicals at concentrations ranging from 10 mg L-1 to 50 mg L-1. The polydimethylsiloxane (PDMS) fiber showed the most representative extraction of analytes. The optimization of the HS-SPME method was performed using a Doehlert design with two variables, and the final conditions were set at 80 °C and 70 min for extraction temperature and time, respectively. A pixel-based data approach was used to implement data-driven soft independent modeling by class analogy (DD-SIMCA). Although DD-SIMCA is a developing area in GC×GC studies, the proposed model produced outstanding results with a sensitivity of 94.3 %, specificity of 95.0 %, and accuracy of 94.5 %, considering the complex and broad compositional range of the modeled mixtures. These findings demonstrated the effectiveness of the OCC model approach in classifying PW samples according to environmental regulations.

Tracking the behavior of an accidental oil spill and its impacts on the marine environment in the Eastern Mediterranean

The eastern Mediterranean region is a vital hub for oil transportation and production because of its strategic location between Europe, Asia, and Africa. But its unique attributes, including narrow shipping routes, heavy marine traffic, and proximity to vulnerable ecosystems, render it particularly susceptible to accidental oil spills. In this research, an oil spill detection model, along with bathymetric and oceanographic parameters, was used to track oil spills that occurred at the Syrian Baniyas Station in the Eastern Mediterranean on August 23, 2021. Furthermore, the study employed a pairwise comparison matrix (PWCM) to assess the relative importance of wind speed and direction, water depth, and sea surface temperature (SST) in the dispersion of oil spills. Analysis of Sentinel-1 data obtained prior to, during, and after the incident revealed the accumulation of oil slicks along the Syrian coast from Baniyas to Latakia for up to twenty days. The spilled oil reached the coast of Cyprus six days after the incident. The study determined that wind speed and direction played a critical role in the dispersion of spilled oil, while water depth and SST were comparatively less significant factors in this process. The overall accuracy (OA) and Kappa coefficient (KC) for land, water, and oil slick classes derived from the random forest (RF) algorithm ranged from 90 % to 98 % and from 0.86 to 0.98, respectively. The spread of oil slicks at the incident location was revealed by the decorrelation stretch and band ratios of Sentinel-2 MultiSpectral Instrument (MSI) data. The accidental oil spill could have negative effects on the organic carbon cycle, chlorophyll production, and ecosystem productivity. It is essential to consider the vulnerability of specific regions in the Eastern Mediterranean to oil spills when developing adaptation strategies.

Methodology for the estimation of an oil spill origin: Analysis of the 2019 Brazilian coast oil spill

This research presents a procedure for determining the origin of marine pollution through the use of a time-direct trajectory modeling, associated with a Kriging metamodel technique and Monte Carlo random sampling. These methods were applied to a real case, specifically the oil spill that affected the Brazilian coast in the second half of 2019 and early 2020. A total of 140 trajectories, defined by the geographical coordinates of the origin and the spill date, were generated through Latin Hypercube Sampling and simulated using the PyGNOME model to construct the Kriging metamodel. The metamodel demonstrated cost-effectiveness by efficiently simulating numerous input data combinations which were compared and optimized based on available real data regarding temporal and spatial pollution distribution.

Shrimp laccase degrades polycyclic aromatic hydrocarbons from an oil spill disaster in Brazil: A tool for marine environmental bioremediation

Our work aims to purify, characterize and evaluate a laccase from by-products of the shrimp farming industry (Litopenaeus vannamei) for the degradation of Polycyclic Aromatic Hydrocarbons (PAHs) from 2019 oil spill in Brazilian coast. The enzyme was purified by affinity chromatography and characterized as thermostable, with activity above 90 °C and at alkaline pH. In addition, the laccase was also tolerant to copper, lead, cadmium, zinc, arsenic, hexane and methanol, with significant enzymatic activation in acetone and 10 mM mercury. Concerning PAHs' degradation, the enzyme degraded 42.40 % of the total compounds, degrading >50 % of fluorene, C4-naphthalenes, C3-naphthalenes, C2-naphthalenes, anthracene, acenaphthene, 1-methylnaphthalene and 2-methylnaphthalene. Thus, this laccase demonstrated important characteristics for bioremediation of marine environments contaminated by crude oil spills, representing a viable and ecological alternative for these purposes.

A custom, low-cost, continuous flow chamber built for experimental Sargassum seaweed decomposition and exposure of small rodents to generated gaseous products

Since 2011, Sargassum events have increased in frequency along the Caribbean and Atlantic coasts. The accumulation and decomposition of large amounts of Sargassum seaweed on beaches pose socio-economic, ecological, and health risks due to the emission of hydrogen sulfide (H2S), methane, and ammonia. However, limited research exists on the emission processes and the health effects of subchronic and chronic exposure to low levels of H2S. Additionally, the absence of emission factor data for Sargassum decomposition on-site makes health risk assessments challenging. This study aimed to create a custom chamber to simulate real-world Sargassum decomposition, exposing experimental animals to the generated gases. Metal content was analyzed, and emission rates were estimated in a controlled environment. The decomposition-exposure system replicated reported environmental gas emissions from the Caribbean region, except for NH3. H2S bursts were observed during the decomposition process at intervals of 2-10 days, with higher frequency associated with larger masses of decomposing Sargassum. The decomposed gas was transferred to the exposure chamber, resulting in an 80-87% reduction in H2S concentration. The maximum H2S emission was 156 ppm, with a concentration ranging from 50.4 to 56.5 ppm. An estimated emission rate of 7-8 g/h for H2S was observed, and significant levels of lead, arsenic, and aluminum were found in beached Sargassum from the northeast coast of Brazil. This study's developed model provides an opportunity to investigate the effects and risks to human health associated with exposure to gases produced during the environmental decomposition of Sargassum seaweed.

Pelagic and estuarine birds as sentinels of metal(loid)s in the South Atlantic Ocean: Ecological niches as main factors acting on bioaccumulation

Activities related to the offshore exploration and production of oil and natural gas provide economic development and an essential energy source. However, besides the risk of petroleum hydrocarbon contamination, these activities can also be sources of metals and metalloids for marine organism contamination. In this research, we evaluated the potential use of two pelagic (black-browed albatross Thalassarche melanophris and yellow-nosed albatross T. chlororhynchos) and one estuarine bird species (neotropical cormorant Nannopterum brasilianus) as sentinels of contamination of As, Cd, Cr, Cu, Pb, Mn, Mo, Zn, Ni, Ba, V, and Hg in an area under influence of oil and gas activities. The analyses were carried out in samples collected from 2015 to 2022 from 97 individuals. A factor alert; an adaptation from the contamination factor is proposed to identify individuals with high concentrations that possibly suffered contamination by anthropogenic origin. Grouping all species, the metal(loid)s with the highest concentrations were in decreasing order: Zn > Cu > Mn > Hg > As > Cd > Mo > V > Cr > Ba > Ni > Pb. Similar concentrations were observed for V, Mn, Cr and Pb among the three species. Pelagic birds showed higher levels of concentrations for Hg, As and Cd. Based on the correlations and multivariate analysis performed, the results indicate that the ecological niche factor has greater relevance in the bioaccumulation of these elements compared to the habitat. Although some individuals showed high concentrations in part of the trace elements, suggesting exposure to anthropic sources, the direct influence of oil production and exploration activities was not observed, suggesting that activities on the continent are the primary contamination source. The results of this work highlight the role of seabirds as sentinels for metal(loid)s, contributing to the knowledge of the occurrence of contaminants in the South Atlantic Ocean.

Concentration of polycyclic aromatic hydrocarbons (PAHs) and histological changes in Anomalocardia brasiliana and Crassostrea rhizophorae from Pernambuco, Brazil after the 2019 oil spill

The present study aimed to analyze the concentrations of polycyclic aromatic hydrocarbons (PAHs) in populations of the shellfish Anomalocardia brasiliana and oysters Crassostrea rhizophorae three years after the 2019 oil spill, as well as evaluate histopathological changes on the gill tissues of the bivalves. Individuals of both species were sampled at points along the northern and southern coast of Pernambuco, Brazil. The permanence of oil residues was confirmed, evidenced by the total concentration of PAHs in the shellfish from the northern coast, which was roughly four times higher than the southern one. Among the PAHs analyzed, the low molecular weight compounds naphthalene and anthracene were the main contributors to the total concentration. Histological changes in the gills of the bivalves, were more severe in the specimens sampled on the north coast indicating alterations in the bivalve's health, mainly on the state's northern coast.

Emerging studies on oil pollution biomonitoring: A systematic review

In the last decade, several methods were applied to monitor the impact of oil pollution on marine organisms. Recent studies showed an eminent need to standardize these methods to produce comparable results. Here we present the first thorough systematic review of the literature on oil pollution monitoring methods in the last decade. The literature search resulted on 390 selected original articles, categorized according to the analytical method employed. Except for Ecosystem-level analyses, most methods are used on short-term studies. The combination of Biomarker and Bioaccumulation analysis is the most frequently adopted strategy for oil pollution biomonitoring, followed by Omic analyses. This systematic review describes the principles of the most frequently used monitoring tools, presents their advantages, limitations, and main findings and, as such, could be used as a guideline for future researches on the field.

Severe ecological impacts caused by one of the worst orphan oil spills worldwide

Orphan oil spills pose a severe risk to ocean sustainability; however, they are understudied. We provide the first synthetic assessment of short-term ecological impacts of the most extensive oil spill in tropical oceans, which affected 2900 km of Brazil's coastline in 2019. Oil ingestion, changes in sex ratio and size of animals, morphological abnormalities of larvae and eggs, mutagenic, behavioral, and morphological alterations, contamination by polycyclic aromatic hydrocarbons, and mortality were detected. A decrease in species richness and abundance of oil-sensitive animals, an increase in opportunistic and oil-tolerant organisms, and simplification of communities was observed. The impacts were observed in sponges, corals, mollusks, crustaceans, polychaetes, echinoderms, turtles, birds, fish, and mammals. The majority of studies were conducted on bioindicator substrate-associated organisms, with 68.4% of the studies examining the benthos, 21.2% the nekton, and 10.4% the plankton. Moreover, most of the current short-term impacts assessment studies were focused on the species level (66.7%), with fewer studies on the community level (19%), and even fewer on oil-affected ecosystems (14.3%). Oil-related impacts were detected in five sensitive habitats, including blue-carbon ecosystems (e.g., mangroves and seagrass beds) and coastal reefs. These results call for the development of new ocean-basin observation systems for orphan spills. Finally, we discuss how these mysterious oil spills from unknown sources pose a risk to sustainable development goals and ocean-based actions to tackle global climate change.

Occurrence of mercury in polychaete species (Annelida) and their associated sediments from an important Southern Atlantic Ocean Bay

In the present study, the Hg levels in freshly collected polychaete species and their associated sediments were evaluated from Todos os Santos Bay, Northeastern Brazil. Additionally, it was also measured the Hg distribution along the annelids' body parts (anterior region, abdomen, and posterior region). Total Hg concentration was as follows: 13.6-144 μg kg^-1 (Scolelepis chilensis, deposit feeder), 8.2-122 μg kg^-1 (Laeonereis acuta, deposit feeder), 95-612 μg kg^-1 (Armandia agilis, deposit feeder); 96.6-206 μg kg^-1 (Lumbrineris sp., carnivorous), 75.3-112 μg kg^-1 (Goniada echinulate, carnivorous), and 115-198 μg kg^-1 (Branchiomma sp., suspension feeder). In turn, Hg levels in sediments ranged from 2.77 ± 0.24 to 6.38 ± 0.15 μg kg^-1. Hg concentrations found in polychaete soft tissues were higher than those found in the sediments. Specific habits, feeding behavior, trophic level, and stressful environmental conditions are the main factors affecting the Hg levels in the species studied. The bioaccumulation factor (BAF), contamination factor (CF), and ecological risk assessment (Er) were calculated. The BAF values were higher than 1 for all studied species, indicating Hg bioaccumulation in the annelids, but the low levels of CF e Er showed those Hg levels present low to no significant ecological risk for the biota and benthonic organisms living in the sediments. Finally, no statistically significant difference was observed for Hg concentration levels along the polychaete body parts.

Citizen science as a tool for collaborative site-specific oil spill mapping: the case of Brazil

Many maritime disasters lead to oil pollution, which undermines ecosystem balance, human health, the prosperity of countries and coastal areas across borders, and people's livelihoods. This is a problem that affects the whole world. Governments must strive to ensure that operations in the marine environment are safe and avoid oil pollution by adopting methods that anticipate future scenarios to mitigate the effects of this pollution when it occurs. This study investigates a method of managing contaminated coastal areas, aiming to contribute to the management of the environmental crisis caused by disasters through the use of online collaborative mapping by volunteer collaborators. Volunteer collaborators have been sending georeferenced data and photographs of locations affected by pollution. This information is processed and printed on a cartographic basis created by the web-mapping platform, Google MyMaps©. Photos of 90 locations were plotted on the map, and the pictures demonstrate that the oil slicks that reached the Brazilian coast had very different shapes and consistency. This research can contribute as a participatory monitoring tool during and after oil spills, promoting the oriented preservation of marine ecosystems through citizen science.

Polycyclic aromatic hydrocarbons in aquatic animals: a systematic review on analytical advances and challenges

Polycyclic aromatic hydrocarbons (PAHs), the main component of petroleum, are a concern due to their environmental persistence, long-range transport, and potential toxic effects on animal, human health, and the environment. PAHs are considered persistent compounds and can be bioaccumulated in sediments and aquatic biota. Determining PAHs in animals and environmental samples consists of three steps: extraction, clean-up or purification, and analytical determination. The matrix complexity and the diversity of environmental contaminants, such as PAHs resulted in the development of numerous analytical techniques and protocols for the extraction of these components and analysis in several samples. This systematic review article seeks to relate the extraction and preparation methods of complex samples from aquatic animals and the two main detection techniques of PAHs. For the elaboration of the research, 67 articles published between 2011 and 2021 were sought, which specifically contemplated the isolation of aquatic extracts and detection and quantification techniques of PAHs.

The most extensive oil spill registered in tropical oceans (Brazil): the balance sheet of a disaster

This article presents a synthesis of information about the massive oil spill in Brazil (2019/2020). The event affected 11 states; however, the majority of the oil residue was collected (~ 5380 tons) near nine states (99.8%) in northeastern Brazil. This spill was not the largest in volume (between 5000 m³ and 12,000 m³) recorded in tropical oceans, but it was the most extensive (2890 km). This spill develops an overwashed tar that remains mostly in the undersurface drift (non-floating oil plume) below 17 m of depth while on the continental shelf. Ten ecosystems were impacted, with potentially more severe effects in mangroves and seagrasses. Certain negative effects are still understudied, such as effects on tropical reefs and rhodolith beds. A total of 57 protected areas in seven management categories were affected, most of which (60%) were characterized as multiple-use regions. The spill affected at least 34 threatened species, with impacts detected on plankton and benthic communities. Acute impacts were reported on echinoderms, coral symbionts, polychaetes, and sponges with evidence of oil ingestion. Socioeconomic impacts were detected in food security, public health, lodging, gender equality, tourism, and fishing, with reduced sales, prices, tourist attractiveness, gross domestic product, and employment. Moreover, chemical contamination was detected in some states by toxic metals (Hg, As, Cd, Pb, and Zn) and polycyclic aromatic hydrocarbons (acenaphthalene, fluoranthene, fluorene, naphthalene, and phenanthrene). This summary aims to aid in the design of science-based strategies to understand the impacts and develop strategies for the most extensive spill observed in tropical oceans.

Polycyclic aromatic hydrocarbons (PAHs) in fishery resources affected by the 2019 oil spill in Brazil: Short-term environmental health and seafood safety

We present herein a short-term impact on marketed fisheries and human health safety in the first three months following the 2019 oil spill in Brazil. Total PAHs in the edible tissues of 34 finfish and shellfish species ranged from 8.71 to 418 ng g^-1 wet weight, with robust evidence supporting crude oil contamination. A prevalence of low molecular weight PAHs was observed, mainly naphthalenes. A decreasing trend in mean total PAHs from mollusks (134 ng g^-1) to crustaceans (73.9 ng g^-1) and to fishes (45.3 ng g^-1) was noted. The spilled oil caused immediate negative impacts on the local seafood market, despite less than 3% of samples exhibited concentrations above levels of concern, revealing a low probability for human health risks. These findings demonstrate that governments must be prepared to provide not only science-based quick responses but also effective science communication for society upon environmental disasters.