Amazonian Tree Mortality during the 1997 El Niño Drought

Abstract: In 1997, the Amazon Basin experienced an exceptionally severe El Niño drought. We assessed effects of this rare event on mortality rates of trees in intact rain forest based on data from permanent plots. Long-term (5- to 13-year) mortality rates averaged only 1.12% per year prior to the drought. During the drought year, annual mortality jumped to 1.91% but abruptly fell back to 1.23% in the year following El Niño. Trees dying during the drought did not differ significantly in size or species composition from those that died previously, and there was no detectable effect of soil texture on mortality rates. These results suggest that intact Amazonian rainforests are relatively resistant to severe El Niño events.     

Recovery of different waste vegetable oils for biodiesel production: A pilot experience in Bahia State,Brazil

In Brazil, and mainly in the State of Bahia, crude vegetable oils are widely used in the preparation of food. Street stalls, restaurants and canteens make a great use of palm oil and soybean oil. There is also some use of castor oil, which is widely cultivated in the Sertão Region (within the State of Bahia), and widely applied in industry. This massive use in food preparation leads to a huge amount of waste oil of different types, which needs either to be properly disposed of, or recovered. At the Laboratorio Energia e Gas-LEN (Energy & Gas lab.) of the Universidade Federal da Bahia, a cycle of experiments were carried out to evaluate the recovery of waste oils for biodiesel production. The experiences were carried out on a laboratory scale and, in a semi-industrial pilot plant using waste oils of different qualities. In the transesterification process, applied waste vegetable oils were reacted with methanol with the support of a basic catalyst, such as NaOH or KOH. The conversion rate settled at between 81% and 85% (in weight). The most suitable molar ratio of waste oils to alcohol was 1:6, and the amount of catalyst required was 0.5% (of the weight of the incoming oil), in the case of NaOH, and 1%, in case of KOH.The quality of the biodiesel produced was tested to determine the final product quality. The parameters analyzed were the acid value, kinematic viscosity, monoglycerides, diglycerides, triglycerides, free glycerine, total glycerine, clearness; the conversion yield of the process was also evaluated.     

Assessment of Water Quality in a Border Region Between the Atlantic Forest and an Urbanised Area in Rio de Janeiro,Brazil

The preservation of water resources is one of the goals of the designation of parks that act as natural reservoirs. In order to assess the impact of the presence of humans in an environmental preservation area bordering urban areas, the presence of four pathogenic enteric viruses [group A rotavirus (RV-A), norovirus (NoV), human adenoviruses (HAdV), and hepatitis A virus (HAV)], as well as the physico-chemical parameters, and Escherichia coli levels were assessed in riverine water samples. From June 2008 to May 2009, monthly monitoring was performed along the Engenho Novo River. RV-A, NoV, and HAdV were observed in 29 % (31/108) of the water samples, with concentrations of up to 10³ genome copies/liter. The natural occurrence of infectious HAdV was demonstrated by Integrated Cell Culture-PCR (ICC-PCR). This study confirms the suitability of using the detection of fecal-oral transmitted viruses as a marker of human fecal contamination in water matrices and indicates the spread of pathogenic viruses occurring in an alleged area of environmental protection.     

Oxidative stress, liver biotransformation and genotoxic effects induced by copper in Anguilla anguilla L.--the influence of pre-exposure to beta-naphthoflavone

Fish are exposed in the aquatic ecosystems to different classes of pollutants. Polycyclic aromatic hydrocarbons (PAHs) and heavy metals represent two important classes of aquatic contaminants. Thus, one lot of European eels (Anguilla anguilla L.) was pre-exposed during 24 h to 2.7 microM beta-naphthoflavone (BNF; a PAH-like compound), and subsequently exposed during 24 h to 0, 1 and 2.5 microM copper (Cu). Additionally, another lot not pre-exposed to BNF was exposed to the same Cu concentrations. BNF pre-exposure promoted a significant increase in liver ethoxyresorufin O-deethylase (EROD) activity, but did not change the other responses investigated in eels. On the other hand, both Cu concentrations did not modify the liver EROD activity either in eels pre-exposed to BNF or not. Liver total cytochrome P450 was increased in eels exposed to Cu 2.5 microM, being significantly only in eels not pre-exposed to BNF. Free sulfhydryl group content was decreased by 1 and 2.5 microM in eels pre-exposed to BNF or not pre-exposed, being significant at 2.5 microM Cu in eels not pre-exposed compared to its control. Liver total glutathione (TG), reduced glutathione (GSH) and GSH/oxidized glutathione (GSSG) levels were slightly decreased by 1 and 2.5 microM Cu in eels pre-exposed to BNF, whereas a slight tendency to increase was observed in eels not pre-exposed. Thus, liver TG and GSH significantly decreased in 2.5 microM Cu BNF pre-exposed eels compared to eels not pre-exposed to BNF. Liver glutathione reductase and catalase activities were significantly inhibited by 1 and 2.5 microM Cu in eels pre-exposed to BNF, concomitantly with a slight liver glutathione peroxidase tendency to decrease. Lipid peroxidation was significantly increased by 1 microM Cu in eels either pre-exposed or not pre-exposed to BNF. Liver H(2)O(2) was significantly increased by 1 microM Cu in eels pre-exposed to BNF. Liver DNA integrity was significantly decreased by 1 and 2.5 microM Cu in eels pre-exposed to BNF. The oxidative stress and genotoxic effects induced by Cu in eels pre-exposed to BNF revealed that the metal effects are potentiated by previous exposure to BNF.     

Tolerance to iron accumulation and its effects on mineral composition and growth of two grass species

This study aimed to assess the influence of excess iron on the capacity of accumulation of this heavy metal, mineral composition, and growth of Setaria parviflora and Paspalum urvillei. Seedlings were submitted to 0.009; 1; 2; 4; and 7 mM of Fe-EDTA. In both species there was an increase in the concentration of Fe, Zn, P, and Ca and a decrease in Mn, K, and Mg in the iron plaque. Both species accumulated more iron in roots. In the shoots, S. parviflora showed higher iron content, except at 7 mM. Iron altered the contents of Fe, Cu, K, and Mg in roots, and of Fe, Mn, Zn, N, P, K, Ca, and Mg in shoots. The two species tolerated high iron concentrations and accumulated high content of this element in both shoots and roots. The iron did not reduce their growth. Both species are indicated for studies aiming restoration of iron-contaminated areas.     

Metal Pollution in the Environment of Minas Gerais State – Brazil

Intense mining activities in Minas Gerais State – Brazil brings out tons of waste to the environment. Considerable concentrations of toxic elements penetrate the soil, ground waters and rivers. This endangers the environment quality not only in the surrounding areas but also in ichthyofauna and in more distant areas of cattle raising and agricultural activities. After seasonal floods, veterinary clinic studies have shown that most animals raised in this region are affected by symptomatologic nervous diseases, still not clearly diagnosed, which suggests intoxication. These pathologies are mostly noted after floods. Instrumental Neutron Activation Analysis was applied to determine Al, As, Au, Ba, Br, Ca, Cl, Co, Cr, Cs, Cu, Fe, Hg, K, La, Mg, Mn, Na, Nd, Rb, Sb, Sc, Sm, Th and Zn in environmental samples. The obtained results show that the water and sediment contaminated with heavy metals and toxic elements from the Das Velhas River upstream basin, the mining region, carry contamination to the ichthyofauna and farming region within a distance of approximately 400 km.     

The contribution of selected organic substrates to the anaerobic cometabolism of sulfamethazine

Biodegradation of organic micropollutants is likely to occur due to cometabolism by particular microbial groups. In an effort to identify the stages of anaerobic digestion potentially involved in the biodegradation of the veterinary antimicrobial sulfamethazine (SMZ), the influence of selected carbon sources (sucrose, glucose, fructose, ethanol, meat extract, cellulose, soluble starch, soy oil, acetic acid, propionic acid and butyric acid) on SMZ removal by anaerobic sludge was evaluated in short-term batch experiments. Adsorption to the granular sludge constituted a significant removal mechanism, accounting for 39% of SMZ removal in control experiments. The presence of glucose, fructose, sucrose and meat extract exerted an inducing effect on SMZ degradation, resulting in removal efficiencies of 54, 53, 58 and 61%, respectively, indicating the occurrence of cometabolism. Time courses of sucrose and meat extract degradation revealed markedly distinct organic acid profiles but resulted in similar SMZ removals. Temporal profiles of acetic and propionic acid degradation were not associated with SMZ removal, as changes in SMZ concentration were observed even after the organic acids had been completely removed. The experimental results suggest that SMZ cometabolism is not associated to sucrose hydrolysis, acetoclastic methanogenesis and acetogenesis from propionic acid.     

Simultaneous and direct determination of glyphosate and AMPA in water samples from the hydroponic cultivation of eucalyptus seedlings using HPLC-ICP-MS/MS

Abstract

Glyphosate is the main herbicide currently used in the world due to wide applicability and efficiency in controlling weeds in many crops. However, its overuse may lead to undesirable impacts on the environment and to human health in the long run. This present study aimed to optimize and validate solid phase extraction (SPE) using an anionic resin for the simultaneous and direct determination of glyphosate and aminomethylphosphonic acid (AMPA) in water samples using high-performance liquid chromatography combined with inductively coupled plasma with triple quadrupole mass spectrometer (HPLC-ICP-MS/MS). The results showed that recovery percentage and relative standard deviation were 103.9?±?7.9 and 99.40?±?9.9% for glyphosate and AMPA, respectively. The validation certified that the method was precise, accurate, linear, and selective, with a limit of quantification of 1.09 and 0.29?μg L^?1 for glyphosate and AMPA, respectively. The optimized methodology reached the concentration factor of 250 times and was successfully applied to analyze water samples from hydroponic cultivation of the eucalyptus seedlings. The results showed that the exudation process occurs at glyphosate doses starting from 2?L ha^?1.