Mariangela Garcia Praça Leite

Growing Eremanthus erythropappus in crushed laterite : a promising alternative to topsoil for bauxite-mine revegetation.

Topsoil is the preferred substrate for areas requiring rehabilitation after bauxite mining. However, topsoil is sometimes lacking and so there is a need to test the suitability of other, locally available substrates. In an abandoned bauxite mine in Southeastern Brazil, small patches of native vegetation spontaneously established in shallow depressions over weathered laterite, suggesting that granulometric reduction may have facilitated the establishment of plants. To test this hypothesis, blocks of laterite collected in the area were crushed to simulate texture observed in the vegetation patches. Topsoil collected in a preserved ferruginous field near to the extraction area was also used as a substrate in which Eremanthus erythropappus seedlings, a native woody species, were grown. Seedlings were cultivated without fertilizers in these two substrates and also directly over the exposed and uncrushed laterite. The species proved to be very promising for the revegetation, showing a high survival rate in all substrates. Higher annual growth rates and higher final biomass values were observed in topsoil, but the granulometric reduction of laterite doubled plant growth rate in comparison to the exposed laterite. This result was likely due to the increased availability of essential nutrients to plants and to the improvement in physical conditions for root growth and functioning. Moreover, seedling allometry was not altered by the type of substrate, suggesting that the species was highly tolerant to the new substrate conditions, a fundamental characteristic for success of revegetation of bauxite extraction degraded areas.

Análise multitemporal das mudanças no uso e ocupação do Parque Estadual do Itacolomi (MG) através de técnicas de geoprocessamento

Over the past forty years, Itacolomi State Park (ISP), located in the region of Ouro Preto/Minas Gerais, has been subject to several changes in its patterns of land use and occupation. These changes were recorded and quantifi ed using remote sensing and GIS techniques, which allowed for the construction of four land use maps, representing the changes in the area during the last four decades. In order to evaluate these changes, the following classes of vegetation were defi ned: Seasonal Semideciduous Forest, Rocky outcrops and Anthropogenic Areas. First, land use maps from 1966 and 1974 were compared, defi ning the fi rst period of analysis; then, 1974 and 1986 maps were considered in the second period of analysis, and fi nally the third period of analysis used 1986 and 2000 maps. The changes that occurred in ISP were predominantly of anthropogenic origin, with greater intensity in the

Influence of soil texture on nutrients and potentially hazardous elements in Eremanthus erythropappus

Understanding the factors that control uptake rates and allocation of chemical elements among plant organs is a fundamental prerequisite to improve phytostabilization techniques of hazardous elements in contaminated areas. The present study shows evidence that different substrate textures (coarse and fine laterite) do not significantly change the partitioning of root and shoot dry biomass and with few exceptions, do not significantly affect the final average concentration of elements in Eremanthus erythropappus, but change the root:shoot allocation of both essential nutrients and elements potentially toxic to biota. Growth on coarse laterite resulted in significant higher K (30%), Mg (34%), P (25%), S (32%), Cu (58%), and Na (43%) concentrations in roots and lower Cd concentration (29%). In shoots, coarse laterite led to reduction in K, Fe, Al, and Cr and increase in Na and Sr concentrations. Changes in element allocation could be, in part, a result of differences in the water availability of substrates. Matric potential in coarse laterite was significantly lower in at least 47% of the days analyzed throughout the year. Changes in element phytoextraction or phytostabilization potential could influence the efficiency of rehabilitation projects in areas degraded by mining activities.

CRESCIMENTO DE ESPÉCIES NATIVAS DE CERRADO E DE Vetiveria zizanioides EM PROCESSOS DE REVEGETAÇÃO DE VOÇOROCAS

Rates of seed germination, plant survival and growth, as measured in the present study, are essential parameters to characterize the biological potential of species for the restoration of degraded areas. The lack of knowledge about these aspects in native species has justified the use of exotic plants in Brazilian gullies revegetation. However, especially in places subject to highly seasonal climate and on oligotrophic soils, exotic species do not always perform well, leading to revegetation failure or significantly increasing the cultivation care needs. To improve the knowledge concerning to the biological potencial of cerrado native species and of an exotic grass which has been used for erosion contention, in the present study, seedlings and clumps of native cerrado species, Cratylia argentea (Desv.) Kuntze and Echinolaena inflexa (Poir.) Chase, and of the exotic grass Vetiveria zizanioides (L.) Nash, were transferred to a gully colluvium in Ouro Preto, Minas Gerais state, where they remained during the dry season of 2010 without application of fertilizers or irrigation. In randomized block design, plots of 1 x 1 m received four planting treatments: clumps of Echinolaena inflexa or Vetiveria zizanioides, and clumps of these grasses intercropped with the legume Cratylia argentea. All grasses and 73% of the legume seedlings survived. As expected, the green cover of Echinolaena inflexadecreased throughout the dry season, however, showing regrowth after the first rains. Leaf area of Vetiveria zizanioides remained active and grew significantly in the period. Cratylia argentea showed high rates of germination and growth; however, nodulation occurred in only two individuals. Thus, there was no influence of the legume on grasses growth. Results indicate that both native species and the exotic grass tested are potential successful plants for gullies replanting. Plants survived and grew on low nutrient substrate and during the critical period of drought without any fertilizer or irrigation application.

Geochemical mapping of arsenic in surface waters and stream sediments of the Quadrilátero Ferrífero, Brazil

A regional study on the arsenic concentration in surface waters and stream sediments, with a density of one sample every 13 km2, was carried out for the first time in the Quadrilatero Ferrifero (Brazil). The region was divided into 3rd order catchment basins, in which 512 areas were sampled. The arsenic concentration was determined in waters and stream sediments after partial digestion with the aid of ICP-OES. The arsenic values found in surface waters ranged from 57.70 to 414 µg.L-1, while for stream sediments, arsenic concentrations ranged from 0.63 to 1691 mg.kg-1, and from the 512 sampling points, 135 (26%) had arsenic concentrations above the limit of detection, which was 0.63 mg.kg-1. It was also found that 106 3rd order catchment basins had values above the third quartile, (5.09 mg.kg-1). The results show that high concentrations of this element are strongly related to the presence of Nova Lima rocks that contain minerals rich in arsenic. However, the anthropogenic influence in such high concentrations cannot be ruled out, as the region has a history of over 300 years of gold mining.

Estrutura da vegetação de mangue associada ao gradiente de inundação no litoral norte do Espírito Santo, Brasil

The mangrove is an ecosystem of great complexity that occurs at the interface between the marine and terrestrial environments. Consequently, it has low richness of vegetables species, adapted to their different physical and chemical conditions. The objectives of this study were to assess the structure and distribution of vegetation in the mangrove river Piraque-acu/ES, associated with abiotic parameters along a flooding gradient. Three hundred and six alive individuals and one dead were recorded in six 100m 2 plots. The plants belong to the following species: Laguncularia racemosa, Rhizophora mangle, Avicennia schaueriana, Terminalia catappa and four undetermined. L. racemosa was the species with the highest density, dominance, basal area and IVI. The average height of the trees was 4.2 m (SD±1.9 m) and CBH (circumference at breast height) was 12.4 cm (SD±9.5), with the majority of individuals in CBH class of 10 cm. The mangrove forest studied is in juvenile stage, with minor structural development. A significant difference was found in the distribution of the species in the area, with associated species occurring in the plot on higher altitudes and lower soil water content. Although all abiotic variables differed among the plots, only substrate moisture showed significant relationship with the abundance of individuals and circumference of the trunks.

Influência geológica em assinaturas químicas das águas e solos do Parque Estadual do Itacolomi, Minas Gerais

This paper presents an analysis of the geochemistry of superficial waters in the Itacolomi State Park and their relationship to the geological scenario and soil geochemistry. Thirty six soil samples were collected at points located in representative areas from the different lithologies. In each region, the soil samples were collected at diverse depths. In addition, eighteen water sampling points were also selected in areas with different drainage patterns. In the ground and water samples, the concentrations of major and trace elements were determined by ICP-OES. Also, physical-chemical parameters were determined for the water samples. The results reveal that geology plays an essential role in the chemical signature of the soils and superficial waters. Comparison with standard values defined by the rules CETESB 195/05 and CONAMA 357/05 proved the influence of pedological and geological characteristics on the water quality. Anomalous concentrations of several elements were found in the water and ground samples. In addition, it was also possible to observe that the regulations for water quality of this area are inadequate since they do not take the geological factors into consideration.

Diagnóstico dos processos de licenciamento e fiscalização das pedreiras de rochas ornamentais na regiãocentro-sul de Minas Gerais

Apresenta-se o diagnostico da analise de 130 processos de licenciamento e fiscalizacao ambiental oriundos de 81 pedreiras de rochas ornamentais, localizadas em cinco municipios da regiao centro-sul de Minas Gerais (Campo Belo, Candeias, Oliveira, Sao Francisco de Paula, Claudio). Tais processos estao arquivados na Fundacao Estadual do Meio Ambiente de Minas Gerais - FEAM. Da analise desses processos, juntamente com as visitas ao campo, constatou-se o desrespeito dos empreendedores aos autos de infracao e as medidas mitigadoras propostas e exigidas pela FEAM. Consequentemente, muitos processos sao arquivados ou ficam pendentes. O resultado mais visivel desse imbroglio e que, na regiao em analise, nenhuma area de extracao de rochas ornamentais foi submetida a processo de recuperacao ambiental, evidenciando a externalizacao de impactos e correspondentes custos sociais para desconforto da populacao da regiao. Os efeitos recentes da atividade de extracao de rochas ornamentais tornam-se ainda mais severos na medida em que, sobretudo nos municipios de Candeias e Sao Francisco de Paula, diversas areas foram paralisadas por razoes de mercado, com consequente reducao da oferta de trabalho para a populacao local.

Avaliação da implantação de fossas sépticas na melhoria na qualidade de águas superficiais em comunidades rurais

In most Brazilian cities, rural communities are clustered in the surroundings of streams that supply water and receive their effluents. The aim of this study was to evaluate the conditions of the quality water in Pau Grande catchment, located in Ouro Branco, Minas Gerais, Brazil, before and after the construction of 20 septic tanks in the community of Castiliano, build in 2006. The monitoring of the basin was conducted between February 2005 and November 2009, using 6 control points. Several water parameters were evaluated: river flow, dissolved oxygen, biochemical oxygen demand, total phosphorus, total coliform, turbidity and pH. Monitoried points downstream of the construction sites showed an increase of more than 100% in dissolved oxygen and a decrease of fecal coliform bacteria (over 800%). Relatively small investments can bring major improvements to the quality of water resources in rural communities areas.

An analysis of the human activities impact on water quantity in the Jequitinhonha Valley, MG/Brazil

Purpose – The purpose of this paper is to analyze the changes of the characteristics of the study area caused by human influence and the reduction of flow rates with time, in Agua Limpa stream basin, Jequitinhonha Valley of Minas Gerais, Brazil.Design/methodology/approach – The study area is a typical arid zone in the northeast of Minas Gerais, Brazil. Field observations, collection and analyses of precipitation, evaporation, temperature and flow rate data were the main approaches used in this study. The data cover the last 50 years, including aerial photographs and satellite images of different dates. The stream flow rate has decreased in the region of the Jequitinhonha valley in the last decades, in particular during draught periods (base flows), with serious social‐economic and environmental consequences. The increase in stream intermittence is responsible for rural exodus to other parts of the country, mainly to Sao Paulo state. The study presented provides decision makers with important information t...