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The impacts of the 2019 Brazilian coast oil spill on mesozooplankton community were investigated using data of before and after spill off the coast of Salvador. The presence of oil droplets was detected in all samples collected in the continental shelf of Salvador, after oil spill (Oct/2020). The total density of oil droplets ranged from 5.03 to 20.37 droplets m–3. The size of oil droplets found this study was similar to natural size of zooplankton foods. The highest percentages of oiled copepods 0.09% and 0.02% were recorded in stations BA1 and BA2 (closest to the coast), respectively. The presence of crude oil droplets was confirmed by the observation of crude oil fluorescence under UVA illumination. Zooplankton assemblage structure exhibited a significant reduction in the taxa number after oil spill. Seven copepods species were registered only before oil spill (Oct/2013, Feb/2014), and during October 2020 were registered 10 fewer species. The total zooplankton density varied from 38.2 to 110.4 org m−3 (October/2013), 87.1 to 803.2 org m−3 (February/2014), 9.4 to 27.4 org m−3 (October/2020) and 17.6 to 45.6 org m−3 (February/2021). The average density values for the period before spill were up to 10 times higher than the average value found after spill. The Analyze of Similarity used in this study revealed that zooplankton assemblages in the continental shelf of Salvador showed changes in its structure after the accident on the Brazilian coast, particularly on October 2020. Overall, our results indicate negative impact of oil spill in the coastal region of Brazil Northeaster on structure of zooplankton assemblages in the continental shelf of Salvador. [ABSTRACT FROM AUTHOR]

Mercury (Hg) contamination has caused ecological and socioeconomic problems worldwide. One of the main Hg contamination routes by the human populations is through fish ingestion. Herein, we analyzed the total Hg concentrations (THg) in highly consumed marine fish species: Brazilian flathead Percophis brasiliensis, Atlantic bigeye Priacanthus arenatus, Stripped weakfish Cynoscion guatucupa, and Jamaica weakfish C. jamaicensis. The specimens were collected from fishing landings off the Rio de Janeiro, SW Atlantic. Additionally, we calculate the estimated weekly intakes (EWI) and the maximum amount of fish (MAF) that can be safely ingested, both based on the provisional tolerable weekly intake (PTWI). The highest THg concentrations were recorded in P. brasiliensis with a mean of 340.59 μg/kg (dry weight) and the lowest in P. arenatus (115.75 μg/kg). THg concentrations were positively related to the δ15N ratios indicating an increase in contamination with trophic level. All samples showed THg concentrations below the established limits by Brazilian and international regulation. Hg intake via human fish consumption does not exceed the PTWI. The EWI varied from 1.41% (P. arenatus size class I) to 11.52% (P. brasiliensis class II) of the PTWI, while the estimated EWI for "fish consumers" varied between 8.35 and 68.07% PTWI. The MAF estimated for an adult (70 kg) could safely consume between 1277.85 and 7075.50 g/week. This study is an important baseline for monitoring and future comparisons. Therefore, it is important to maintain monitoring of mercury levels in fish species in different marine regions, especially those species most consumed by humans. [ABSTRACT FROM AUTHOR]