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 CaCO3. Muddy sediments from a depositional site (P2) presented the highest concentrations of metals, despite SEM/AVS not indicating bioavailability. Bioaccumulation factors showed high ratios for Cd, Ni, and Zn, while associations between the contents of mud, organic matter, CaCO3 and metals in sediments and tissues of A. flexuosa were indicated by a principal component analysis. The SEM/AVS was not effective to predict the bioavailability through dissolved metals. The results showed that contaminants were bioavailable, while the performed bioaccumulation test proved to be a reliable technique for assessing sediment contamination in estuarine regions. Moreover, A. flexuosa was considered an adequate test organism for bioaccumulation studies.

Metal-Associated Biomarker Responses in Crabs from a Marine Protected Area in Southeastern Brazil.

The environmental quality of a Ramsar wetland site located at the Cananéia-Iguape-Peruíbe Protected Area (CIP-PA), in São Paulo, Brazil, was assessed by geochemical analyses and biomarker assessments (GPx, GST, GSH, GST, MT, LPO, DNA damage) performed in swimming crab Callinectes danae Smith, 1869 organs (posterior and anterior gills and hepatopancreas) to estimate sediment contaminant bioavailability. The results indicated that two sampling stations, PT and PM, exhibited the worst environmental conditions, as sediments collected at both points contained metal contamination, while crabs exhibited significant responses for GPx, GST, and LPO (mostly during winter). Sediment contamination tended to be associated to fine sediments (both seasons) and organic matter (winter). During the summer survey, Pb concentrations in sediments of station PT exceeded the Brazilian Sediment Quality Guidelines (SQGs) and the Canadian Interim Marine Sediment Quality Guidelines. Metal concentrations in sediments sampled in winter were higher compared with summer, with Co, Ni, and Pb exceeding SQGs levels at PT, whereas Co, Ni, Hg, Zn, and Pb exceeded SQGs at PM. Biomarker induction during summer appeared to be caused by natural variables (water salinity and temperature, and molting cycle), whereas oxidative stress and tissue damage during winter appeared to be more clearly linked to metal contamination. Anterior gills presented the clearest signs of seasonal variability, being more responsive to sediment contamination. The results suggest that metals originated from the upper Ribeira de Iguape River are transported toward the estuarine system, causing effects on C. danae individuals. Additionally, seasonality is a strong factor concerning CIP-PA toxicity, since the rainfall regime significantly modifies the freshwater flow and, consequently, estuarine water salinity, suspended particle and metal inputs, as well as the location of depositional areas. Thus, efforts to mitigate CIP-PA contamination should be based on the control of upstream pollution sources.

Anthropization as a determinant factor in the genetic structure of Copernicia prunifera (Arecaceae).

This study uses ISSR molecular markers to characterize the demographic pattern, and spatial genetic structure (SGS) at different life stages of development (cohorts) in a natural population of Copernicia prunifera in the Rio Grande do Norte State, Brazil. All individuals were sampled and georeferenced in a 0.55-ha plot. The demographic analyses showed a clustered pattern in the first-distance classes and a random or segregated pattern at higher distance classes for all cohorts. Among the three studied life stages, juveniles showed the greatest value for Nei's genetic diversity index (HE = 0.369), while the lowest was found among reproductive adults (HE = 0.341). Greater genetic differentiation was found within life stages (98.61%) than among stages (1.39%). The total population (N = 161) showed positive and significant kinship in the first-distance class (12.3 m). The juveniles showed significant kinship up to 10.5 m. Non-reproductive adults had a positive kinship in the first-distance class (11.0 m) and a random distribution of genotypes in the remaining classes, while reproductive adults showed a random spatial distribution of genotypes. Tests for genetic bottleneck showed that the number of loci with excess observed heterozygosity was greater than expected. The SGS results reflected the restricted seed dispersion of the species, and the genetic bottleneck reflected the reduction of genotypes as a result of the anthropization of C. prunifera natural environments.

Total Mercury in Carnivorous Fish from Brazilian Southeast.

Total mercury concentrations were determined by atomic absorption spectrometry in muscle tissue of two commercially important species of carnivorous fishes croaker (Micropogonias furnieri) and cutlassfish (Trichiurus lepturus) caught in Itaipu estuary, Rio de Janeiro. In this study, whitemouth croaker presented more mercury than Atlantic cutlassfish. Bioaccumulation differences can be explained by the biological behavior of juveniles whitemouth croaker, that remain in the estuary up to maturity, which makes them good indicators of local environmental impacts (0.110 mg Kg(-1) HgT). It also can be explained by differences in nutritional requirements between the different life stages of two species. The analysis showed the presence of low levels of the metal. However, our results suggest a possible risk to human health, depending on the level of fish consumption.

The Brachyura and Anomura fauna (Decapoda; Crustacea) in the Arvoredo Marine Biological Reserve on the southern Brazilian coast.

Eight species of Brachyura and two species of Anomura were registered for the first time on the Santa Catarina coast, in the waters around the Arvoredo Marine Biological Reserve. The animals were collected by scuba divers, between 3 and 22 meters depth, from September 2001 to February 2003. A total of 31 decapod species were collected, and most of the new occurrences had already been registered in the adjacent northern waters.

Lead and cadmium contamination in sediments and blue crabs Callinectes danae from a Ramsar wetland in southeastern Brazil

Contaminação de chumbo e cadmio em sedimentos e siris Callinectes danae provenientes de uma Zona Úmida de Importância Internacional Ramsar no sudeste do Brasil. A Área de Proteção Ambiental Cananéia-Iguape-Peruíbe (APA-CIP), na costa sudeste do Brasil, foi designada como Zona Úmida pela conferência de Ramsar. Esse estuário é impactado por aportes de água contaminada e sedimentos do Rio Ribeira de Iguape (RIR), no estado de São Paulo. O aporte de metais provém principalmente de atividades históricas de mineração e metalurgia na bacia hidrográfica do RIR. Este estudo teve como objetivo avaliar as concentrações de Pb e Cd nos tecidos moles de siri-azul (Callinectes danae) da APA-CIP, e determinar se os níveis desses metais nos tecidos dos siris estão correlacionados com as concentrações de metais nos sedimentos do estuário. Sedimentos e siris foram coletados durante as estações chuvosa (Março) e seca (Setembro). As concentrações de Pb nos sedimentos em duas estações no estuário excederam as diretrizes de qualidade dos sedimentos, nas concentrações de 13.08 e 40.24 µg.g-1 de peso seco, respectivamente. Apesar dessas altas concentrações de Pb nos sedimentos, os níveis de Pb nas brânquias e nos tecidos (hepatopâncreas) dos siris eram relativamente baixos. As concentrações de Cd nos sedimentos do estuário foram relativamente baixas, mas as concentrações nos tecidos dos siris foram elevadas. Por exemplo, as concentrações de Cd no hepatopâncreas de siris coletados em Março em duas estações de coleta foram de 21.73 e 4.24 µg.g-1, respectivamente. Esses resultados indicam que C. danae pode depurar Pb rapidamente, enquanto são capazes de acumular e mal depurar Cd. Há indicações de que concentrações de Cd no hepatopâncreas de C. danae estão correlacionadas com as concentrações nos sedimentos, mas fatores como a variação do conteúdo de areia e lama dos sedimentos e o potencial de migração dos siris dentro do estuário podem apresentar fatores de variabilidade. Esses dados indicam que uma ação governamental é necessária para controlar a contaminação desta Zona Úmida como Patrimônio Mundial.

The Brachyura and Anomura fauna (Decapoda; Crustacea) in the Arvoredo Marine Biological Reserve on the southern brazilian coast

Eight species of Brachyura and two species of Anomura were registered for the first time on the Santa Catarina coast, in the waters around the Arvoredo Marine Biological Reserve. The animals were collected by scuba divers, between 3 and 22 meters depth, from September 2001 to February 2003. A total of 31 decapod species were collected, and most of the new occurrences had already been registered in the adjacent northern waters.

Oito espécies de Brachyura e duas espécies de Anomura foram registradas pela primeira vez na costa de Santa Catarina, em águas no entorno da Reserva Biológica Marinha do Arvoredo. Os animais foram coletados por meio de mergulho autônomo, entre 3 e 22 metros de profundidade, de setembro 2001 a fevereiro de 2003. Um total de 31 espécies de Decapoda foram coletadas e a maioria das novas ocorrências já haviam sido registradas em águas adjacentes ao norte da Reserva.