Reinaldo Antônio Petta

Assessing Homogeneity and Climate Variability of Temperature and Precipitation Series in the Capitals of North-Eastern Brazil

A 51-year dataset (1961 to 2011) from nine meteorological stations in the capitals of northeastern Brazil (NEB), with daily data of precipitation totals and of mean, minimum and maximum temperatures, was statistically analyzed for data homogeneity and for signals of climate variability. The hypothesis was explored that a connection exists between inhomogeneities of the time series and the meteorological systems influencing the region. Results of the homogeneity analysis depend on the selected test variable, the test algorithm and the chosen significance level; all more or less subjective choices. Most of the temperature series was classified as “suspect”, while most of the precipitation series was categorized as “useful”. Displaying and visually checking the time series demonstrates the power of expertise and may allow for a deeper data analysis. Consistent changes in the seasonality of temperature and precipitation emerge over NEB despite manifold breaks in the temperature series. Both series appear to be coupled. The intra-annual temperature and precipitation ranges have increased, along with an intensified seasonal cycle. Temperature mainly increased during DJF, MAM and SON, with decreases in JJA being related to wetter conditions and more frequent heavy precipitation events. Drought conditions mostly increased in SON and DJF, depending on the timing of the local dry season.

Mutagenic potential assessment associated with human exposure to natural radioactivity

Lucrécia city, known to harbor a high cancer rate, is located in a semiarid region characterized by the presence of mineral reservoirs, facing a high exposure to metal and natural radioactivity. The present study aimed to assess the environmental scenario at a semiarid region located in Northeastern Brazil. Metal concentration, alpha and beta radiation, and cyanobacteria content in tap water along with indoor radon and gamma emitters (U, K and Th) concentrations were measured. In addition, mutagenic and nuclear instability effects were assessed using buccal micronucleus cytome assay. The study included five samplings corresponding to a period between 2007 and 2009. Drinking water from Lucrécia city presented levels of Mn, Ni and Cr along with cyanobacteria in concentrations one to four times higher than regulatory guidelines considered. Furthermore, high levels of all the tested radionuclides were found. A high percentage of the houses included in this study presented indoor radon concentrations over 100 Bq m-3. The mean annual effective dose from Lucrécia houses was six times higher than observed in a control region. The levels of exposure in most of the Lucrécia houses were classified as middle to high. A significant mutagenic effect, represented as an increase of micronuclei (MN) frequency and nuclear abnormalities as nuclear buds (NB), binucleated cells (BN), and pyknotic cells (PYC) were found. The results obtained highlight the role of high background radioactivity on the observed mutagenic effect and could help to explain the exacerbated cancer rate reported in this locality.

Influence of mining activity on the downstream sediments of scheelite mines in Currais Novos (NE Brazil)

The study area is one of the most important mineral provinces of the Rio Grande do Norte State (NE Brazil), which has been extensively exploited since 1940. This article presents a geochemical investigation of stream sediments taken in the drainage system between the Brejuí and Barra Verde scheelite mines, and the Gargalheiras municipal reservoir, in Acari city. In addition to the major elements, the trace elements V, Cr, Co, Ni, Cu, Zn, As, Rb, Sr, Zr, Mo, Sn, Ba, W were analyzed and compared to metal levels reported in the literature for the same area. The elements W, Mo, Cu, Sn and in part Zn are enriched in sediments of rivulets forming the drainage system close to the mining district. This is due to emission from uncovered mine waste dumps. Dispersion of elements is controlled by both, aeolian as well as fluvial transport. The concentration of Cu in stream sediments close to the mines reaches toxic levels. At the mouth of the drainage system to the reservoir, the elements W and Mo are still enriched in the stream sediments relative to the geogenic background by factors of 15 and 11, respectively. This indicates the probable influence of mining activity to the reservoir sediments, and mobilization of W and Mo in the reservoir water cannot be ruled out.

Análise das similaridades das cartas de vulnerabilidade à erosão realizadas por dois operadores zonais de álgebras de mapas

The present work aims to compare the erosionvulnerability maps of the sub-basin of the Low (downstream?) Piracicaba watershed, State of Sao Paulo, using two distinct operators of map algebra as a way of verifying the level of similarity between the products. These operators are called “Zonal Average” and “Zonal Majority” and are compared statistically using an error matrix, which is obtained by cross tabulation, the Kappa index and the linear dispersion coefficient (obtained from the dispersion diagram). The results show that the two maps are very similar to each other and that the analyst may choose either of the two operators.

BANCO DE DADOS GEOGRÁFICOS NO SPRING VISANDO A ANÁLISE GEOAMBIENTAL NA REGIÃO DO SERIDÓ

A Provincia Pegmatitica da Borborema e uma das mais importantes areas geoeconomicas dos estados do Rio Grande do Norte e Paraiba, decorrente das inumeras ocorrencias minerais. Esta atividade economica induz a producao de uma enorme quantidade de dados espaciais e nao-espaciais, porem de maneira isolada e em diversos formatos. Desta forma, se faz necessario a organizacao destes dados visando armazenar, consultar, visualizar, manipular e gerar informacoes para variados fins. Assim, este trabalho tem como objetivos especificos: gerar mapas tematicos contendo informacoes dos componentes dos meios fisico, biotico e antropico, a partir da adequacao de dados ja existentes (mapas tematicos), da carta topografica e da fotointerpretacao de imagens de satelites que possa subisidiar na estruturacao e implementacao de um Banco de Dado Georreferenciado (BDG) com potencialidade de armazenar, integrar, consultar, visualizar, plotar e analisar, numa unica base de dados, de informacoes espaciais e nao-espaciais provenientes de varios tipos e escalas da area de estudo, visando concentrar todas as informacoes necessarias com vistas a subsidiar o desenvolvimento sustentavel, nas questoes socio-economicas e ambientais. Para tal, foi utilizado o programa de geoprocessamento SPRING (Sistema de Processamento de Informacoes Georreferenciadas); as ferramentas geotecnologicas, como Sensoriamento Remoto, Cartografia Tematica, Sistema de Posicionamento Global e imagens de satelite. A area de estudo compreende a Folha Jardim do Serido (SB.24-Z-B-V), escala 1:100.000, delimitada pelos paralelos 6o 30’ a 7o 00’ de latitude Sul e pelos meridianos 37o 00’ a 36o 30’ de longitude Oeste, situada na porcao extremo sul da meso-regiao Central do Estado do Rio Grande do Norte e porcao extremo Centro - Norte do Estado da Paraiba. Os resultados obtidos permitem concluir que os objetivos deste trabalho foram atingidos, ou seja, estruturar e implementar um BDG (Banco de Dado Georreferenciado) com potencialidade de integrar e analisar, numa unica base de dados, informacoes espaciais e nao-espaciais provenientes de varios tipos e escalas e realizar uma analise preliminar geoambiental da area de estudo.