Eduardo von Sperling

Emissão de gases de efeito estufa no ciclo de vida do etanol: estimativa nas fases de agricultura e industrialização em Minas Gerais

This research presents an estimate of greenhouse gas emissions (CO2, CH4 e N2O) in the stages of agriculture and sugarcane industrialization for the production of ethanol in mills located in the state of Minas Gerais, Brazil. Life Cycle Assessment principles were considered in the quantification of emissions. The use of fuels, agricultural inputs, N2O emissions on soil, sugarcane burning emissions and use of chemical products of 11 mills were considered in this study. The results show a total emission of 1,539.60 kg CO2eq/ha·year, considering as the main key sources: sugarcane burning and use of fuels, which account for more than 50% of the total emissions.

The process of biomass formation as the key point in the restoration of tropical eutrophic lakes

The paper presents initially some specific features of tropical lakes (high recycling rates, elevated primary production during the whole year, high nutrient assimilation, high settling velocity of nutrients, intense organic matter decomposition, high grazing rates), which leads to the establishment of a very dynamic ecosystem. Due to these characteristics the warm water lakes show completely different reactions to the impacts derived from the phenomenon of eutrophication in comparison with lentic systems situated in temperated regions. Moreover in shallow lakes occurs an almost permanent mixing process, which in its turn allows the resuspension of nutrients and a consequent increase in the primary productivity. The key point at the study of the eutrophication of tropical lakes is the comprehension of the complex relationship between nutrient concentration and biomass formation. The paper presents the result of some studies carried out by the author in Brazilian lakes and reservoirs, leading to the conjecture that the nutrient mass in a water body is often not directly linked with the phytoplankton growth. The strategies for the recovery of degraded tropical lakes should hence be directed towards a control of the formed biomass and not to a limitation in the nutrient input, as is usually the case in cold water lakes.

Avaliação do gerenciamento dos resíduos de serviços de saúde em municípios da região metropolitana de Belo Horizonte (Brasil)

The inadequate management of health wastes units may expose patients, workers, community and environment to relevant risks. One of the main factors that contributes to a marked trend in adopting alternative management strategies is that the same destination is frequently used for regular urban wastes disposal. Field researches have been carried out in the metropolitan region of Belo Horizonte in order to evaluate the corresponding procedures for the management of solid wastes from health services. Special attention was dedicated to the level of compliance with legal standards. This survey identified several misprocedures, mainly in respect to the use of individual protection equipments, inappropriate transport of the wastes and existence of irregular disposal sites.

Fatores determinantes das florações de cianobactérias na água do Rio Doce, Minas Gerais, Brasil

From 2005 there were successive blooms of toxic and nontoxic cyanobacteria in water from Doce River. At that time, the possible causes of these blooms were studied and the extensive winter period in the watershed area was one of the main causes. The main objective of this study was to statistically associate some quality and environmental parameters of the river water for a period of five years, to meet and explain the possible correlations. Cyanobacteria were present in the water of the Doce River in the 10 sampling points evaluated in the period from 2008 to 2012. In cluster analysis between the collection points, the sample station RD44 stood alone and presented during the dry seasons of the years the highest densities of thermotolerant coliform. By means of principal component analysis, it was found that increased density of cyanobacteria was associated with a reduction in temperature of the water, turbidity and the concentration of phosphorus, which are characteristic conditions of river waters in Minas Gerais during the winter period (dry season). In the same period, there were increases in the concentrations of chlorophyll a, dissolved oxygen, nitrates, the stoichiometric ratio N/P and the Water Quality Index. After 2009, successive cyanobacteria blooms have been registered. This reinforces the theory that the damming of the river has had a growing influence on cyanobacteria blooms. They may have contributed to reduce the turbidity of river water, increase in nitrate concentration and thermotolerant coliform density.

Modelagem da Lagoa da Pampulha: uma ferramenta para avaliar o impacto da bacia hidrográfica na dinâmica do fitoplâncton

In urban areas the increasing imperviousness is responsible for rising runoff volume and speed, leading to a greater capacity to load nutrients and pollutants into reservoirs. In order to study the impacts of catchment changes on the phytoplankton dynamics in urban lakes, a modelling approach in which a hydrological model is connected to an ecological lake model is proposed for Lake Pampulha (Brazil). In this paper we present the methodology used to link both models. Lake Pampulha and its catchment area were intensively monitored between October 2011 and June 2013 in order to provide data for the calibration and validation of both models. The results of the hydrologic model showed good agreement with the in situ measurements, and the Nash coefficient ranged from 0.70 to 0.88. The lake ecological model have successfully represented the cyanobacteria dynamics (normalized mean average error: 0.25-0.42, Pearson coefficient: 0.82-0.89, p<0.0001). Monitoring and modelling showed that cyanobacteria blooms are quite disturbed by water column mixing caused by rain events. The mathematical tool developed here can be used to assess different scenarios of climate changes or catchment area changes and can be very helpful for the management of urban water resources.

Qualidade da água durante a formação de lagos profundos em cavas de mineração: estudo de caso do lago de Águas Claras - MG

The paper presents the results of a broad monitoring program carried out during the beginning of the filling process of Lake Aguas Claras, Brazil. This lake was created after the exhaustion of an iron ore mining activity. In its final conformation the lake will have a surface area of 0,7 km 2 and the maximum depth of 234 m, which will make it the deepest lake in the country. The results of a two years monitoring program show the prevalence of good water quality (well oxygenated, low degree of mineralization, absence of organic and mineral contamination), but also a quite interesting shift in the dominance of phytoplanktonic groups, indicating the high instability of lakes that are undergoing a process of formation.

Aspectos de Qualidade de Água em Bacias de Retenção Urbanas

O trabalho apresenta resultados de monitoramento de qualidade da agua em cerca de 50 bacias de retencao francesas. Inicialmente e feita uma revisao sobre estudos ecologicos em bacias de retencao, destacando-se, em escala internacional, a carencia de dados especificos sobre a qualidade da agua destes novos sistemas hidricos. A seguir sao discutidos separadamente os principais parâmetros de qualidade da agua nas bacias estudadas, constatando-se o predominio de condicoes satisfatorias na maioria das bacias, muito embora associadas a uma alta produtividade primaria dos ambientes aquaticos. Nao se observa um padrao homogeneo de qualidade da agua entre as bacias pesquisadas. As informacoes decorrentes deste estudo, com as necessarias consideracoes de particularidades, sobretudo climaticas, podem ser extrapoladas para a realidade brasileira, tendo em vista a crescente utilizacao destes sistemas alternativos de drenagem urbana em nosso pais.

Uso de técnica nuclear em amostras de interesse na agricultura

The concern related to environment is growing. Due to this, it is needed to determine chemical elements in a large range of concentration. The neutron activation technique (NAA) determines the elemental composition by the measurement of artificial radioactivity in a sample that was submitted to a neutron flux. NAA is a sensitive and accurate technique with low detection limits. An example of application of NAA was the measurement of concentrations of rare earth elements (REE) in waste samples of phosphogypsum (PG) and cerrado soil samples (clayey and sandy soils). Additionally, a soil reference material of the International Atomic Energy Agency (IAEA) was also analyzed. The REE concentration in PG samples was two times higher than those found in national fertilizers, (total of 4,000 mg kg-1 ), 154 times greater than the values found in the sandy soil (26 mg kg-1 ) and 14 times greater than the in clayey soil (280 mg kg-1 ). The experimental results for the reference material were inside the uncertainty of the certified values pointing out the accuracy of the method (95%). The determination of La, Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Lu in the samples and reference material confirmed the versatility of the technique on REE determination in soil and phosphogypsum samples that are matrices for agricultural interest.

Use of nuclear techniques in the study of the behaviour of rare earth elements on the use of phosphogypsum in Cerrado agriculture

Phosphogypsum (PG) is a by-product of phosphoric acid industry. In Brazil, this material has been used as a conditioner for soils with high levels of aluminium. Taking into account the presence of radionuclides and Rare Earth Elements (REEs) in this material, a research project has been conducted in order to investigate the impact of using PG in crops cultivated in Cerrado soils. For this purpose a set of greenhouse experiments has been conducted in two types of soil to determine the transfer factor of REEs from soil to crops. This paper reports results of mineralogical phases and REEs concentration in PG samples. The REE most present in PG samples was Ce (1730 ppm) followed by La (973 ppm) and Nd (791 ppm). Sm (85 ppm), Eu (29 ppm), Tb (8 ppm) and Yb (5 ppm) appear in smaller proportions. The main crystalline compound found in PG samples was gypsum (CaSO4.2H2O).