Zinc stable isotopes in mangrove crabs as tracers of anthropogenic contamination in a tropical estuary.

Our study presents a novel approach for tracing anthropogenic zinc (Zn) bioaccumulation in mangrove crabs using Zn stable isotope compositions (δZn). We analyzed δZn and elemental composition in crab tissues from Brazilian mangroves within a coastal lagoon historically impacted by electroplating waste. Crabs from the mangrove area near the old electroplating plant exhibited the highest Zn concentrations in both muscle and hepatopancreas, likely reflecting the high Zn bioavailability in these sediments.

Description and Patterns of Hyperostosis in Plata Pompano, Trachinotus marginatus Cuvier, 1832.

This study describes the occurrence of hyperostosis, to the best of our knowledge, for the first time in Trachinotus marginatus Cuvier 1832 and examines its patterns in 21 specimens from Rio de Janeiro, Brazil. Radiographic images revealed the presence of the condition in 76.2% of the individuals, affecting five distinct bone regions: supraoccipital (76.

Comparisons of Hyperostotic Bones in Two Species of the Genus Oligoplites Gill, 1863 in the Southern Brazilian Coast.

The description of skeletal disorders is commonly reported in fish species raised through aquaculture; however, wild marine fish may also exhibit high frequencies of anomalies, particularly the development of hyperostosis, a condition that causes thickening of the bones. Specimens of Oligoplites saliens (n = 15) and Oligoplites palometa (n = 14) were radiographed to verify hyperostotic bone occurrences. Hyperostosis was detected in all individuals (> 400 mm TL) analysed for both species, occurring in six distinct regions of the skeleton (supraoccipital bone, cleithrum, dorsal pterygiophores, anal pterygiophore, haemal spines, and neural spines), regardless of the sex of the individuals.

A global survey on total arsenic concentrations in sharks.

Several shark species worldwide present high total arsenic (As) concentrations in muscle tissue, although to what extent has not yet been systematized. This study assessed total As concentrations in different shark species, as these animals comprise a significant fishery resource worldwide and are paramount for ecosystem equilibrium. A scientometric assessment retrieved 21 articles published between 1993 and 2023 reporting total As concentrations in muscle tissue of 27 shark species belonging to 16 different genera landed around the globe.

Copper and zinc isotope systematics in different bivalve mollusk species from the French coastline: Implications for biomonitoring.

Zinc (Zn) and copper (Cu) stable isotopic compositions have been analyzed in various species of bivalve mollusks worldwide, but no comprehensive systematic interspecies comparison exists. Thus, we assessed isotope differences between species harvested in emblematic French coastal ecosystems to unveil biologically driven Cu and Zn isotope fractionation patterns. Inter-species isotopic variability of Cu is larger than Zn, with organisms that regulate internal concentrations displaying preferential bioaccumulation of heavy isotopes.

Phosphate buffering in mangrove sediment pore water under eutrophication and deforestation influences.

Phosphorus (P) behavior was evaluated in mangrove wetlands impacted by urban sewage, including a deforested site. Sediment cores were analyzed for grain size, organic carbon, total nitrogen, stable isotopes (δC and δN), P contents, and pore water PO concentrations and net consumption/production rates. Under stronger eutrophication influence, significantly higher P (1390 vs.

Geochemical fractionation of trace metals and ecological risk assessment of surface sediments in Sepetiba Bay, Brazil.

The Sepetiba Bay (Southeast Brazil) is a known Cd- and Zn-contaminated site that received spills of a large slag pile leachate from a Zn smelter. With important harbors, Sepetiba Bay demands periodic dredging operations which affect the mobility of the metals. The main goal of this work was to assess metal mobility in sediments and its associated toxicity in a fictive dredging area, to evaluate the risks of the operation.

The French Mussel Watch Program reveals the attenuation of coastal lead contamination over four decades.

The mid-20th century industrial peak caused severe global lead (Pb) marine contamination. Although Europe initiated Pb emission reduction regulations in the 1980s, the short- and long-term impacts remain unclear. This study investigates the evolution of Pb contamination on the French coast through elemental and isotope analysis in oysters and mussels from the French "Mussel Watch" Program.

Antimicrobial resistance and biotechnological potential of plastic-associated bacteria isolated from an urban estuary.

Plastics have quickly become one of the major pollutants in aquatic environments worldwide and solving the plastic pollution crisis is considered a central goal of modern society. In this study, 10 different plastic samples, including high- and low-density polyethylene and polypropylene, were collected from a deeply polluted urban estuary in Brazil. By employing different isolation and analysis approaches to investigate plastic-associated bacteria, a predominance of potentially pathogenic bacteria such as Acinetobacter, Aeromonas, and Vibrio was observed throughout all plastic samples.

Assessment of eutrophication from phosphorus remobilization after resuspension of coastal sediments from an urban tropical estuary.

Dredging activities cause sediment resuspension, which can change the bioavailability of nutrients such as phosphorus (P) in aquatic ecosystems due to remobilization. This study evaluated the remobilization of P in the solid and dissolved phase before and after sediment resuspension in the Meriti and Iguaçu River estuaries and the Rio de Janeiro and Niterói harbor in Guanabara Bay (Rio de Janeiro, Brazil). Three water and sediment samples were collected at each point.

Copper and lead isotope records from an electroplating activity in sediments and biota from Sepetiba Bay (southeastern Brazil).

An old electroplating plant in Sepetiba Bay discharged metal-enriched wastes into the surrounding mangroves for 30 years (from the 1960s to 1990s), resulting in a hotspot zone of legacy sediments highly concentrated in toxic trace metals. This study applies Cu and Pb isotope systems to investigate the contributions of past punctual sources relative to emerging modern diffuse sources. The electroplating activity imprinted particular isotopic signatures (average δCu: 0.

Spatial distribution of total mercury and methylmercury in the sediment of a tropical coastal environment subjected to heavy urban inputs.

Jurujuba Cove is located in Guanabara Bay (adjacent to highly populated city of Rio de Janeiro, Brazil), which receives diffuse sources of contaminants along with two main freshwater inputs (the Cachoeira and Icaraí rivers), and hosts mussel farms. The main goal of this work was to evaluate the total mercury (THg) and methylmercury (MeHg) concentrations distributions in the sediments of the cove and their associations with physical and chemical parameters, thereby assessing their geochemical behavior. Twenty samples of surface sediments were collected and characterized for grain size, pH, redox potential, organic carbon, total phosphorus, THg and MeHg.

Mercury methylation upon coastal sediment resuspension: a worst-case approach under dark conditions.

Mercury behavior upon resuspension of sediments from two impacted areas of Guanabara Bay was evaluated to assess worst-case methylmercury (MeHg) responses, under dark experimental conditions to prevent demethylation by photolysis. Study areas include the Rio de Janeiro Harbor (RJH) and the chlor-alkali plant-affected Meriti River (MR) estuary. Total mercury (THg) and MeHg concentrations were determined along 24-h experiments of sediment resuspension in the bay water in dark conditions.

Linking eutrophication to carbon dioxide and methane emissions from exposed mangrove soils along an urban gradient.

Mangroves are one of the most important but threatened blue carbon ecosystems globally. Rapid urban growth has resulted in nutrient inputs and subsequent coastal eutrophication, associated with an enrichment in organic matter (OM) from algal and sewage sources and substantial changes in greenhouse gas (GHG) emissions. However, the effects of nitrogen (N) and phosphorus (P) enrichment on mangrove soil OM composition and GHG emissions, such as methane (CH) and carbon dioxide (CO), are still poorly understood.

Mercury distribution in water masses of the South Atlantic Ocean (24°S to 20°S), Brazilian Exclusive Economic Zone.

Mercury (Hg) is a toxic globally spread pollutant that has been found at increasing concentrations in the South Atlantic Ocean. The present work provides the first insight into the total mercury (HgT, unfiltered waters) content in the water of the Brazilian Exclusive Economic Zone (BEEZ), within a 24°S to 20°S. Water samples were collected from surface to 3400 m depth along transects, and analyzed with atomic fluorescence.

Ecological risks associated to trace metals of contaminated sediments from a densely urbanized tropical eutrophic estuary.

The sediment contamination by trace metals in coastal aquatic ecosystems is a worldwide environmental problem, since metals can be toxic, persistent, and bioaccumulated. In case of natural events, such as storms, or anthropogenic activities, like dredging, the sediment resuspension to the water column occurs and can solubilize metals, probably increasing their bioavailability and consequently the risk to aquatic life. This study evaluated the bioavailability on reactive trace metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in estuarine sediments from Iguaçu and Meriti Rivers, both in the drainage basin of Guanabara Bay (Rio de Janeiro, Brazil).

Mangrove sediments as long-term mercury sinks: Evidence from millennial to decadal time scales.

The mercury (Hg) cycle in estuaries has been globally discussed, although Holocene deposition in mangrove sediments remains unknown. Herein, a sediment core from a mangrove system in southeastern Brazil was C-dated to evaluate millennial Hg deposition. The highest Hg concentrations (1010-2540 ng g) in surface sediments were explained by emissions from a chlor-alkali industry (1964 CE).

Arsenic contamination in widely consumed Caribbean sharpnose sharks in southeastern Brazil: Baseline data and concerns regarding fisheries resources.

Although shark meat is consumed worldwide, elevated arsenic (As) concentrations have been increasingly reported. The Caribbean sharpnose shark (Rhizoprionodon porosus) is a widely consumed fishing resource in Brazil, with scarce information on As burdens to date. Herein, commercial-sized juvenile Caribbean sharpnose sharks from Rio de Janeiro (Brazil) were assessed in this regard, presenting significantly higher hepatic As concentrations in males (8.

Sediment contamination and toxicity of Marine Protected Areas in southeastern Brazilian coast: A baseline for management planning.

Recent studies have shown that the effectiveness of establishing Marine Protected Areas (MPAs) is threatened by toxic effects of contaminants. São Paulo is the most economically developed state of Brazil, and its coast is protected by a system of MPAs, including the North Shore Marine Protected Area (NSMPA). The present study provides a first assessment of sediment quality in NSMPA and two reference sites.

Anthropogenic and environmental influences on nutrient accumulation in mangrove sediments.

Here we provide a global review on nutrient accumulation rates in mangroves which were derived from sixty-nine dated sediment cores, addressing environmental and anthropogenic influences. Conserved mangroves presented nitrogen and phosphorous accumulation rates near to 5.8 ± 2.

Metal Bioaccumulation by the Neotropical Clam Anomalocardia flexuosa to Estimate the Quality of Estuarine Sediments.

This investigation evaluated the bioaccumulation potential of the tropical estuarine bivalve Anomalocardia flexuosa for trace metals. To this aim, chemical and sedimentological analyses and bioaccumulation tests were performed. The sediments were mainly composed by fine-sands and mud, with variable levels of organic matter and CaCO.

Trace metal dynamics in an industrialized Brazilian river: A combined application of Zn isotopes, geochemical partitioning, and multivariate statistics.

The Paraiba do Sul (PSR) and Guandu Rivers (GR) water diversion system (120 km long) is located in the main industrial pole of Brazil and supplies drinking water for 9.4 million people in the metropolitan region of Rio de Janeiro. This study aims to discern the trace metals dynamics in this complex aquatic system.

Changes in Cd and Zn distribution in sediments after closure of an electroplating industry, Sepetiba bay, Brazil.

The spatiotemporal attenuation of Cd and Zn concentrations was assessed in sediments from Sepetiba Bay, which is a coastal system that has been historically impacted by industrial wastes. The evolution of contamination over the years shortly before and after cessation of electroplating industry activities, by the end of 1990's, was elucidated by reviewing the existing datasets for the whole bay area. Metal concentrations exceed Brazilian Sediment Quality Guidelines in most regions, corresponding to concentrations 3 to 4 orders of magnitude higher than background levels and Enrichment Factors reaching values significantly higher than 40 for both elements.