Genotoxicity Biomonitoring Along a Coastal Zone Under Influence of Offshore Petroleum Exploration (Southeastern Brazil).

Offshore oil exploration creates threats to coastal ecosystems, including increasing urbanization and associated effluent releases. Genotoxicity biomarkers in mussels were determined across a gradient of coastal zone influences of offshore petroleum exploration in southeastern Brazil. Coastal ecosystems such as estuaries, beaches and islands were seasonally monitored for genotoxicity evaluation using the brown mussel Perna perna. The greatest DNA damage (5.2% ± 1.9% tail DNA and 1.5‰  ± 0.8‰ MN) were observed in urban estuaries, while Santana Archipelago showed levels of genotoxicity near zero and is considered a reference site. Mussels from urban and pristine beaches showed intermediate damage levels, but were also influenced by urbanization. Thus, mussel genotoxicity biomarkers greatly indicated the proposed oil exploration and urbanization scenarios that consequently are genetically affecting coastal organisms.

Relative effects of nutrient emission from intensive cage aquaculture on the semiarid reservoir water quality.

The effects of cage aquaculture on freshwater ecosystems are determined by multiple farming and environmental variables, and thus, the assessment of a wide range of abiotic and biotic variables enables better understanding of the impacts generated by this nutrient source. This study was carried out at Castanhão reservoir located in the State of Ceará, which is the largest Brazilian producer of Nile tilapia in cage systems, wherein about 8000 reservoirs provide a vast area to expand not only this important socio-economic but also pollution-prone activity. Nutrient mass budget, water quality monitoring, hydrodynamic characterization, and elemental/stable isotopic composition of end-member products were measured in cage aquaculture and other reservoir areas in order to determine the relative effects on reservoir conditions. Nutrient budgets showed that 34% of the artificial feed was lost to the water column but water quality monitoring and isotopic composition analysis suggested that the cages were not extensively impacting the water quality probably because of the physiographic and hydrodynamic features of the cage site.

Mismatch between sediment metal distribution and pollution source gradient: a case study of a small-size drainage basin (Southeastern Brazil).

Metal contamination in aquatic environments may occur when the anthropogenic emission exceeds the natural contribution although other factors might influence the metal distribution. In the small-size Macaé river basin, most of the metal emission was originated from anthropogenic sources suggesting a contamination status. Total and exchangeable metal concentrations were determined in sediments from the pristine upstream to the urban estuary and compared to the metal content in rocks to establish contamination and background concentrations. The enrichment of Pb in sediments compared to the regional background and high exchangeable concentrations suggest the influence of anthropogenic sources on Pb distribution. Al, Fe Mn, Zn, Ba, Cu, Cr, Ni concentrations in sediments were similar to the rock content and the values were considered regional background. Spatial distribution did not follow the whole-basin emission source gradient suggesting that despite actual anthropogenic sources, the sediment mineralogy and basin geomorphology might influence the sediment metal distribution.

Acute toxicity bioassay with the amphipod, Grandidierella bonnieroides S. after exposure to sediments from an urban estuary (Macaé River Estuary, RJ, Brazil).

Acute toxicity to Grandidierella bonnieroides and physicochemical analysis were used for quality assessment of the sediment of the Macaé River urban estuary, located in the Brazilian coast where rapid socioeconomic growth has been induced by offshore oil and gas exploration at the Campos Basin. Sediment samples were collected during four events in four sampling sites of the estuary and also in a control site. Organism mortality after exposure to the estuarine sediments was, on average, 30 % a value higher than in the control site where it was 10 %. This result together with the physicochemical analysis suggests an initial toxicity condition of the sediments from this aquatic coastal environment.

Assessment of a coastal lagoon metal distribution through natural and anthropogenic processes (SE, Brazil).

The present study intends to assess the metal pollution of a eutrophic coastal lagoon, analyzing the long-term and actual metal content in surface sediments, suspended particles, aquatic macrophyte and fish species, and the loads emitted from natural processes and anthropogenic sources, including the relative emission of domestic untreated sewage. Distribution indicated contamination of suspended particles with Cd and the predominance of Pb in the bioavailable form in surface sediments which may explain Cd and Pb contamination in fish. Domestic untreated sewage was an important source of Cu and due to the lagoon's management, this source may be increasing the metal content in the lagoon's surface sediments. Soil loss, atmospheric deposition and solid waste disposal also contributed to metal inputs to the lagoon. Extensive contamination has been prevented by the lagoon's management such as sandbar opening. Metal retention within the watershed soils reduce the effective metal transference and lagoon pollution.

Land-sea mercury transport through a modified watershed, SE Brazil.

River management has altered the land-sea transport of water, sediments, and chemical compounds with profound impacts on the structure of continental and costal ecosystems. Understanding riverine transport across modified watersheds allow for better assessment of the influence of river management on material fluxes to coastal waters. Here, we assess the quantitative and qualitative aspects of mercury (Hg) transport across a modified watershed by diversion of Paraíba do Sul River waters into Sepetiba Bay, Brazil. We measured concentrations and speciation of Hg in water samples collected at sites within the modified watershed. These data, together with water discharge and sediment load from numerical models and measurements were used to estimate mass balances. In the Sepetiba watershed, mercury is mainly associated with suspended sediments (90%) and therefore Hg flux displayed the characteristic trend of downstream reduction due to trapping efficiency of particulate load by successive reservoirs. The mass balance suggests that the major source of mercury to Sepetiba Bay is the erosion of soil-derived particles from the drainage basin rather than mercury diverted from Paraíba do Sul River watershed.

Estimating the importance of natural and anthropogenic sources on N and P emission to estuaries along the Ceará State Coast NE Brazil.

The Northeastern semi-arid Brazilian region is experiencing rapid social and economic development based on improving water management and even in areas of low human occupation, anthropogenic emissions of N and P surpass natural emissions in at least one order of magnitude and these additional loads can alter the water quality of the receiving estuaries. This study estimates, using an emission factor approach, the annual emissions of N and P from natural processes and anthropogenic sources for estuaries along the Ceará State, NE Brazil. Emission factors from natural sources are one to two orders of magnitude lower than those for anthropogenic sources. Among the anthropogenic activities, the aquaculture is responsible for most N emission (0.52 t km(-2) year(-1)) followed by waste water and husbandry. For P, the largest average emission factors are from husbandry (0.30 t km(-2) year(-1)), waste water and agriculture.

Changes in mangrove extension at the Pacoti River estuary, CE, NE Brazil due to regional environmental changes between 1958 and 2004 / Alteração na cobertura de manguezais ao longo do estuário do Rio Pacoti, CE, NE do Brasil devido a mudanças ambientais entre 1958 e 2004

Regional land use changes at the Pacoti River basin, Ceará State, NE Brazil resulted in doubling the mangrove area from 1958 (0.71 km²) to 2004 (1.44 km²). Most of the increase was due to the replacing of salt marsh vegetation inland, but also along newly formed islands and enlarged river banks. Drastic reduction in freshwater supply and sediment accumulation due to river damming were probably the major drivers of the increased mangrove cover. However, changes due to global climate changes can not be ruled out.

Mudanças regionais no uso da terra no estuário do Rio Pacoti, Estado do Ceará, NE do Brasil resultaram em um aumento de duas vezes na área original de manguezais presente neste estuário entre 1958 (0,71 km²) e 2004 (1,44 km²). A maior parte desta expansão ocorreu através da colonização de áreas anteriormente cobertas por vegetação de salgado, mas também ao longo de praias alargadas do rio e em ilhas recém formadas. A diminuição do fluxo de água doce e a acumulação de sedimentos devidos à construção de barragens foram as principais causas deste aumento, embora alterações resultantes de mudanças climáticas globais não possam ser descartadas.