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

Essential and non-essential elements in marine silverside Odontesthes argentinensis from southwestern Atlantic coast: Tissues bioaccumulation, biomagnification and public health risk assessment

In order to assess the metal pollution in the southwestern Atlantic coast, levels of eleven metals: Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, and Zn and one metalloid: As in water and tissues of Odontesthes argentinensis from the Samborombón Bay (SB) and Partido de La Costa (PC) were examined. Additionally, bioconcentration, and bioaccumulation factors, estimated daily intake (EDI) for adults and children, and the hazard risk for fishermen and general populations were evaluated. Cadmium, Cu and Zn levels in the water samples exceeded the limits established by international guidelines for the protection of aquatic life in marine environments (CCME). The liver showed the highest concentrations of As, Cu, Fe, and Zn, while muscle showed the least levels of all elements examined. Bioaccumulation of Cd, Cu, Mn, Pb and Zn were observed in all tissues, while Ba and Sr bioaccumulated significantly in the gills. The fish δ15N values significantly varied between sites, however, no biodilution or biomagnification was observed. The Target Hazard Quotients (THQ) and the Carcinogenic Risk (CR) indices suggest that there is no human health risk to the fishermen and general populations from the O. argentinensis consumption. Furthermore, As (27%) and Cr (33%) concentrations in silversides from PC and SB, respectively, exceeded the levels recommended by local and international guidelines.

Bioaccumulation of trace elements and hydrocarbons in chondrichthyans of the western Arabian Gulf: Environmental and human health risk assessment and implications for conservation

This is a first attempt to assess the levels of trace elements, PAHs, and TPHs in six elasmobranch species (Carcharhinus dussumieri, C. sorrah, Chiloscyllium arabicum, Gymnura poecilura, Sphyrna lewini, S. mokarran) from the Arabian Gulf. The chemical analysis showed that the concentrations of contaminants differed significantly between liver and muscle samples with both pelagic and benthic species and all families. For all species, contaminant concentrations were significantly higher in the liver than in the muscle. While muscle contaminant concentrations differed significantly with respect to species' lifestyles and families, those of liver showed no significant differences between pelagic and benthic species, neither between the four families nor between the six species. None of the analysed contaminants exceeded the internationally recognized standards in all studied species. These results enrich the knowledge on the bioaccumulation of contaminants in elasmobranchs and allow to assess the environmental status of the Arabian Gulf.

Trophic Chain Organochlorine Pesticide Contamination in a Highly Productive Upwelling Area in Southeastern Brazil

Organochlorine pesticides (OCP) are legacy anthropogenic compounds known to persist for several years in the environment. The continuous use of some OCP, such as DDT, after restrictions in developing countries are cause of concern, due to their deleterious effects to marine life and humans. Studies assessing OCP contamination in coastal environments are still scarce in South America and there is a need to understand the impacts from trophic chain accumulation of these pollutants in marine life. In this study, we have assessed OCP levels in muscle and liver and estimated the biomagnification factor in several upwelling system trophic chain members, including fish, squid, and marine mammal from Southeastern Brazil. DDT degradation product DDE was the OCP detected in the highest concentrations in Franciscana dolphins (Pontoporia blainvillei), 86.4 ng·g^-1 wet weight, and fish muscle and liver. In general, higher OCP levels were found in liver than in muscle, except for croaker. Biomagnification factors (BMF) of OCP in the top predator P. blainvillei and the carnivorous cutlass fish (Trichiurus lepturus) were on average between 0.2 and 1.8. Continued OCP monitoring in this region is warranted to better understand the distribution and fate of these compounds over time, with the goal to establish strategies for the conservation of local dolphin species and to assess human health risks from local coastal region populations.

Assessment of Human Health Risk of Metal(Loid) Content in Brazilian Sardine Along the Southwestern Atlantic

The Brazilian sardine (Sardinella aurita) is an important food resource found in the subtropical Southwestern Atlantic Continental Shelf (CSSWA), but limited information about its metal(loid) concentrations is available, restricting effective risk assessment by its consumption. On this research, we hypothesized that S. aurita presents different metal(loid) concentrations within a latitudinal gradient in the CSSWA (northern and southern sectors). We also assessed the S. aurita consumption contamination risk in both sectors of the CSSWA. The results indicated that S. aurita might present different chemical and contamination profiles between the observed sectors, with highlights to As, Cr, and Fe at greater levels than the safety limits established by regulatory agencies. Such finds could be explained by urbanization, industrialization, continental and oceanographic processes along the CSSWA, corroborating our hypothesis for most observed metals(loid). On the other hand, our risk assessment analysis of metal(loid) concentrations did not indicate hazards for human consumption.

First metal and metalloid study assessment for the Black Triggerfish Melichthys niger (Bloch, 1786): Baseline data from a pristine South Atlantic oceanic island

Metal and metalloid concentrations in Black Triggerfish, Melichthys niger (Tetraodontiformes, Balistidae), and sediments from Trindade Island, an isolated, pristine, and understudied environment in the Southwestern Atlantic Ocean were determined. Several elements were detected in sediment, including Rare Earth Elements (REE). Hg and the REE Nd were, however, not detected. Elements determined in triggerfish are indicative of systemic circulation and the presence of toxic elements indicates an exposure source. No significant associations were detected between elements in fish organs and total length, suggesting no bioaccumulation with age, nor between organs and sediment, indicating probable dietary origin. Biliary excretion indicated a local chronic source of As and Cd and non-quantifiable REE elimination. Hg concentrations were over thresholds that affect fish biochemistry processes. These baseline data are valuable concerning elemental contamination in remote oceanic islands, with the potential to be applied to future biomonitoring efforts and conservation measures for reef ecosystems worldwide.

New Occurrences of the Tiger Shark (Galeocerdo cuvier) (Carcharhinidae) off the Coast of Rio de Janeiro, Southeastern Brazil: Seasonality Indications

The tiger shark Galeocerdo cuvier (Péron & Lesueur, 1822) (Carcharhinidae) is classified as near-threatened along the Brazilian coast, in line with its global categorization. Although Rio de Janeiro, located in southeastern Brazil, is internationally identified as a priority shark conservation area, many shark species, including tiger sharks, are landed by both industrial and artisanal fisheries in this state. However, there is a lack of detailed information on the species capture pressures and records for the state of Rio de Janeiro. Therefore, the aims of this study were to expand the tiger shark record database and to improve upon future conservation and management strategies. Tiger shark records from four coastal Rio de Janeiro regions were obtained by direct observation. The information obtained from fishery colonies/associations, environmental guards, researchers, and scientific articles, totaling 23 records, resulted in an approximately 5-fold increase in the number of tiger shark records off the coast of the state of Rio de Janeiro. A possible seasonality pattern concerning the size of the captured/observed animals was noted, emphasizing the need to consider the coast of Rio de Janeiro as an especially relevant area for at least part of the life history of tiger sharks.

Subcellular metal partitioning as a novel tool in ecotoxicological elasmobranch assessments: The case of lesser numbfish (Narcine brasiliensis) affected by the Mariana dam disaster in Southeastern Brazil

This study comprises a novel report on subcellular metal partitioning and metallothionein (MT) metal detoxification efforts in lesser numbfish (Narcine brasiliensis) electric ray specimens, as well as the first assessment on MT contents in any ray electric organ. Individuals sampled from an area in Southeastern Brazil affected by the Mariana dam rupture disaster were assessed concerning subcellular metal partitioning and MT metal-detoxification in the liver, gonads, electric organ and muscle of both adults and embryos. Yolk was also assessed when available. Relative total and heat-stable (bioavailable) metal and metalloid comparisons between adults and embryos in different developmental stages demonstrates maternal transfer of both total and bioavailable metals and significant MT associations demonstrate the detoxification of As, Ag, Mn, Ni, Cd, Co, Cu, Se and V through this biochemical pathway. Our findings expand the lacking ecotoxicological assessments for this near-threatened species and indicates significant ecological concerns, warranting further biomonitoring efforts.