Heitor Evangelista

Apportionment of black carbon in the South Shetland Islands, Antarctic Peninsula

concentration of 8.3 ng m � 3 was consistent with global model estimates for this region. The intermittent coupling mechanism between the regional circulation of the low-level jets and the passages of the frontal systems explained the transport of BC from areas of burning biomass in Brazil to the northern Antarctic Peninsula. Principal component analysis applied to BC, Radon, ANC, and meteorological data presented significant factor loadings linking BC with 222 Rn and with wind velocity corroborating with this hypothesis.

Composição química da chuva e aporte atmosférico na Ilha Grande, RJ

Wet (n = 21) and dry (n = 23) deposition samples were collected from March to September 2002 at the southern coast of Ilha Grande. Rainwater pH varied from 4.3 to 6.3 and ionic concentrations (in µmol L-1) decreased in the order Cl- > Na+ > Mg2+ > SO42- > NO3- ~ NH4+ > K+ ~ H+ > Ca2+. Scavenging of sea-salt aerosols was the major source of Cl-, Na+, Mg2+, and Ca2+. Half of total SO42- was non-sea-salt SO42-. Total deposition fluxes of NH4+, NO3-, and non-sea-salt SO42- were respectively 9.3, 17.8, and 16.0 mol ha-1 month-1.

Transport of crustal microparticles from Chilean Patagonia to the Antarctic Peninsula by SEM-EDS analysis

The individual elemental composition of insoluble airborne particulates found in King George Island (KGI), Antarctic Peninsula (atmosphere, snow, firn and ice deposits) and in the atmosphere of Chilean Patagonia by SEM-EDS analysis identify probable sources and transport mechanisms for the atmospheric aerosols observed in these regions. Insoluble airborne particulates found in the snow, firn and ice in a core from Lange Glacier (KGI) call for significant crustal influence, mainly associated with aluminium potassium, aluminium calcium and magnesium iron silicates together with other aluminium silicates of calcium and magnesium, among rare others containing Ti, Ni and Cr. Our study suggests that 95% of the bulk mode insoluble particulates deposited in Lange Glacier can be explained by atmospheric transport from Chilean Patagonia. Cyclonic systems passing between southernmost South America and the Antarctic Peninsula are the most probable atmospheric transport mechanism, tracked by measurements of 222Rn and Si.

Indoor air quality of a museum in a subtropical climate: The Oscar Niemeyer museum in Curitiba, Brazil

The assessment of damage to indoor cultural heritage, in particular by pollutants, is nowadays a major and growing concern for curators and conservators. Nevertheless, although many museums have been widely investigated in Europe, the effects of particulate matter and gaseous pollutants in museums under tropical and subtropical climates and with different economic realities are still unclear. An important portion of the worlds cultural heritage is currently in tropical countries where both human and financial resources for preserving museum collections are limited. Hence, our aim is to assess the damage that can be caused to the artwork by pollution in hot and humid environments, where air quality and microclimatic condition differences can cause deterioration. As a case study, particulate matter as well as gases were collected at the Oscar Niemeyer Museum (MON) in Curitiba, Brazil, where large modern and contemporary works of art are displayed. NO2, SO2, O3, Acetic Acid, Formic Acids and BTEX, in the ambient air, were sampled by means of passive diffusive sampling and their concentrations were determined by IC or GC-MS. The particulate matter was collected in bulk form and analyzed with the use of energy dispersive X-ray fluorescence and aethalometer. The chemical compositions of individual particles were quantitatively elucidated, including low-Z components like C, N and O, as well as higher-Z elements, using automated electron probe microanalysis. The gaseous and particulate matter levels were then compared with the concentrations obtained for the same pollutants in other museums, located in places with different climates, and with some reference values provided by international cultural heritage conservation centers. Results are interpreted separately and as a whole with the specific aim of identifying compounds that could contribute to the chemical reactions taking place on the surfaces of artifacts and which could potentially cause irreversible damage to the artworks.

A high spatial resolution outdoor dose rate map of the Rio de Janeiro city, Brasil, risk assessment and urbanization effects.

Geophysical surveys have been widely used for geological mapping, and with appropriate ground calibration the database can be converted to radiometric surveys. Herein we present a case study of a high resolution map of the City of Rio de Janeiro, Brazil, constructed by integrating aerial and in situ (ground) measurements. This allowed assessing the influence of urbanization observed between 1978 and 2009 on radiation external exposure. Radiometric, geological and demographics databases were integrated in a Geographic Information System (GIS) facility. The average absorbed dose rate recorded for the city was 96 ± 0.3 nGy h(-1) and ranged from 22 to 152 nGy h(-1) among districts. The corresponding annual effective dose was determined as 0.09 ± 0.01 mSv. The number of people at risk per year according to the estimated natural radiation levels was 17 ± 1.4, among the 28,000 new cases estimated by the INCA (Brazilian National Cancer Institute) within a population of approximately 6.3 million people.

South Tropical Atlantic anti-phase response to Holocene Bond Events

Records of the climatic impacts of the North Atlantic Bond cycles over the subtropical Southern Hemisphere re-main scarce, and their mechanism is a topic of active discussion. We present here an alkenone-based reconstruct-ed sea surface temperature (SST) of a sediment core retrieved from the Brazilian Southwestern Tropical Atlantic (SWTA), Rio de Janeiro, together with a sediment SST record from the Cariaco Basin. The sediment cores span the period 2,100 B.P. – 11,100 B.P. Morlet-wavelet analysis detected marked periodic signals of ~ 0.8, ~ 1.7 and ~2.2 kyr, very similar and with comparable phases to the hematite-stained-grain time series from the Northern North Atlantic in which the cyclic pattern was recognized as Bond cycles. Our result corroborates the modeled surface ocean anti-phase thermal relation between the North and the South Atlantic. We attribute this behavior to the slowing of the Atlantic Meridional Overturning Circulation. The relative SST warming at Rio de Janeiro and the relative cooling at Cariaco were comparatively more pronounced during the early Holocene (from 11 to 5 kyr B.P.) than in more recent time.

Environmental Assessment of Admiralty Bay, King George Island, Antarctica

Monitoring has been developed by Antarctic Programmes such as Antarctic New Zealand (www.antarcticanz.govt.nz) and the US Antarctic Programme (USAP) (http://www.usap.gov) considering expansion of human activities and inevitable environmental.

Photoprotective and toxicological activities of extracts from the Antarctic moss Sanionia uncinata

Background: The Antarctic moss Sanionia uncinata (Hedw.) Loeske has shown high ultraviolet (UV)-absorbers content after exposition to high levels of UV-B radiation and can be an important source of antioxidants. Objective: The aim was to investigate photoprotection and mutagenicity by the aqueous extract (AE) and hydroethanolic extract (HE) from the Antarctic moss S. uncinata. Materials and Methods: Photoprotective activities were determined through survival curves of Escherichia coli strains, after UV irradiation in an aqueous solution of thymine and in vitro sun protection factor (SPF). The Salmonella/microsome assays were applied to assess the mutagenicity. Results: Both extracts induced photoprotection against UV-C radiation. The AE showed a higher protection than the hydroethanolic one against UV-induced thymine dimerization. The SPFs were low in both extracts. In association to benzophenone-3 a significant increase in the SPF was detected for the AE, and a significant decrease was induced by the HE. No mutagenicity was found in the both extracts. Furthermore, it was observed absence of cytotoxicity. Conclusion: Water-extractable compounds seem to contribute on photoprotection of this Antarctic moss.

Effects of Sanionia uncinata extracts in protecting against and inducing DNA cleavage by reactive oxygen species.

Abstract When mosses are exposed to increased quantities of ultraviolet (UV) radiation, they produce more secondary metabolites. Antarctica moss Sanionia uncinata (Hedw.) Loeske has presented high carotenoid contents in response to an increase in UVB radiation. This moss has been recommended as a potential source of antioxidants. In the present work, the protective and enhancing effects of aqueous (AE) and hydroalcoholic (HE) extracts of S. uncinata on the cleavage of supercoiled DNA were evaluated through topological modifications, quantified by densitometry after agarose gel electrophoresis. Total phenolic contents reached 5.89 mg/g. Our data demonstrated that the extract does not induce DNA cleavage. Furthermore, both extracts showed antioxidant activity that protected the DNA against cleavage induced by (i) O2•−, 89% (AE) and 94% (HE) (P < 0.05), and (ii) .OH, 17% (AE) and 18% (HE). However, the extracts intensified cleavage induced by Fenton-like reactions: (i) Cu2+/H2O2, 94% (AE) and 100% (HE) (P < 0.05), and (ii) SnCl2, 62% (AE) and 56% (HE). DNA damages seem to follow different ways: (i) in the presence of Fenton-like reactions could be via reactive oxygen species generation and (ii) with HE/Cu2+ could have also been triggered by other mechanisms.

Potential source regions of biogenic aerosol number concentration apportioning at King George Island, Antarctic Peninsula

Abstract Nowadays it is well accepted that background aerosols in the boundary layer over remote oceans are of marine origin and not aged continental. Particularly in the Atlantic sector of the Southern Ocean at least four main important regions exhibit significant ocean primary productivity. They are the Bellingshausen–Amundsen Sea, the Weddell Sea, the southern Argentinean shelf and the southern Chilean coast. In this work, we have combined ground-based continuous atmospheric sampling of aerosol number concentration (ANC), over-sea dimethyl sulphide (DMS) measurements, chlorophyll a (chl a) concentration provided by Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite images, in situ meteorological data and monthly regional NCEP-NCAR re-analysis wind fields in order to investigate the relative contribution of each of the above regions to the apportionment of the ANC at King George Island (KGI), South Shetland Islands. Our results suggest that, at least during the period from September 1998–December 1999, the southern Argentinean shelf acted as the main contributor to the ANC measured in KGI.