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Heavy metal contamination in sandy beach macrofauna communities from the Rio de Janeiro coast, Southeastern Brazil
2017
Cabrini, Tatiana M.B. | Barboza, Carlos A.M. | Skinner, Viviane B. | Hauser-Davis, Rachel A. | Rocha, Rafael C. | Saint'Pierre, Tatiana D. | Valentin, Jean L. | Cardoso, Ricardo S.
We evaluated concentrations of eight heavy metals Cr, Zn, Pb, Ni, Cu, Cd, Co and V, in tissues of representative macrofauna species from 68 sandy beaches from the coast of Rio de Janeiro state. The links between contamination levels and community descriptors such as diversity, evenness, density and biomass, were also investigated. Metal concentrations from macrofaunal tissues were compared to maximum permissible limits for human ingestion stipulated by the Brazilian regulatory agency (ANVISA). Generalized linear models (GLM's) were used to investigate the variability in macrofauna density, richness, eveness and biomass in the seven different regions. A non-metric multidimensional scaling analysis (n-MDS) was used to investigate the spatial pattern of heavy metal concentrations along the seven regions of Rio de Janeiro coast. Variation partitioning was applied to evaluate the variance in the community assemblage explained by the environmental variables and the heavy metal concentrations. Our data suggested high spatial variation in the concentration of heavy metals in macrofauna species from the beaches of Rio de Janeiro. This result highlighted a diffuse source of contamination along the coast. Most of the metals concentrations were under the limits established by ANVISA. The variability in community descriptors was related to morphodynamic variables, but not with metal contamination values, indicating the lack of direct relationships at the community level.Concentration levels of eight heavy metals in macrofauna species from 68 sandy beaches on Rio de Janeiro coast (Brazil) were spatially correlated with anthropogenic activities such as industrialization and urbanization.
Mostrar más [+] Menos [-]Management and environmental risk study of the physicochemical parameters of ballast water
2017
Shipping is a vital industry for the global economy. Stability of ships, provided by ballast water, is a crucial factor for cargo loading and unloading processes. Ballast water treatment has practical significance in terms of environmental issues, ecosystem, and human health, because ships discharge this water into the environment before loading their cargos. This study reviews the common methods for ballast water management – exchange, heating, filtration, ultrasonic treatment, ultraviolet irradiation, chemicals, and gas supersaturation – to select the best one. This study compares water temperature, salinity, dissolved oxygen, polycyclic aromatic hydrocarbons (PAHs), and heavy metals (Co, Cr, Ni, Pb) for ballast tanks of selected ships with the recipient port environment in the Persian Gulf as a case study. The exchange of ballast water in the ocean and/or its treatment on board to prevent inadvertent effects on the environment's physicochemical conditions is related to vessel characteristics, legislation, and the environmental condition. Ecological risk study showed that the salt content in ballast water is close to that of seawater, but the values of Cr (2.1mg/l) and Ni (0.029mg/l) in ballast water are higher than those in seawater (1 and 0.004mg/l, respectively).
Mostrar más [+] Menos [-]Newly discovered seagrass beds and their potential for blue carbon in the coastal seas of Hainan Island, South China Sea
2017
Jiang, Zhijian | Liu, Songlin | Zhang, Jingping | Zhao, Chunyu | Wu, Yunchao | Yu, Shuo | Zhang, Xia | Huang, Ji | Huang, Xiaoping | Kumar, Manoj
Eight new seagrass beds were discovered along the coastline of Hainan Island in South China Sea with an area of 203.64ha. The leaf N content of all seagrasses was above the median value, indicative of N limitation, with their C:N ratio recorded significantly lower than the limiting criteria. This suggested that N is not limiting but in replete status. Further, the lower C content observed in the seagrass leaves was accompanied by higher nutrient concentration. The mean seagrass biomass C was 0.23±0.16MgCha−1, while the average sediment organic carbon (SOC) stock was 7.02±3.57MgCha−1. The entire SOC stock of the newly discovered seagrass beds was 1306.45 Mg C, and the overall SOC stock of seagrass bed at Hainan Island was 40858.5 Mg C. These seagrass beds are under constant threats from sea reclamation, nutrient input, aquaculture activities for oyster and snail farming, and fishing activities.
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