Correlations between radiometric analysis of Quaternary deposits and the chronology of prehistoric settlements from the southeastern Brazilian coast

Natural gamma radiation measurements of sand deposits were carried out in order to study the chronology of prehistoric colonization of the Brazilian coast during the Holocene. The method employs thorium, uranium and potassium as tracers of the geological provenance of Quaternary deposits, where artificial shellmounds are found. The so-called sambaquis are archaeological settlements, characteristic of fisher-gatherers, specialized in the exploitation of shellfish. Our results show a considerable positive correlation between the formation of coastal deposits, based on cross plots of eTh/eU and eTh/K, and the antiquity of its prehistoric human occupation.     

Environmental assessment of water-courses of the Turvo Limpo River basin at the Minas Gerais State, Brazil

A study was performed to evaluate the environmental contamination in the Turvo Limpo River basin which receives effluent discharges from domestic (residential and commercial) activities. The watercourses examined were the São Bartolomeu Stream, Turvo Sujo River, and Turvo Limpo River, located in the Minas Gerais State, Brazil. Water samples were collected at the river-side and analyzed for evaluation of pollutant inputs. The pH, temperature, electrical conductivity, redox potential (Eh), dissolved oxygen (DO), total and settleable solids, visual color, hardness, chemical oxygen demand (COD), biochemical oxygen demand (BOD), chloride, total phosphate, total nitrogen, ammonia nitrogen, nitrate, total coliforms and E. coli, as well as the Cd, Pb, Cu, and Zn speciation were determined in the watercourses. The data obtained were compared with those of the Brazilian Environmental Standards and with data from non-contaminated areas. River water characteristics in some sites were far from the limit values established for superficial waters with satisfactory quality. For instance, the BOD values reached 411 mg L^?1 for a maximum limit of 10.0 mg L^?1, while the ammonia nitrogen concentration reached 28 mg L^?1 for a maximum limit of 13.3 mg L^?1. Some sites showed E. coli values above those of non-contaminated regions. Besides the effects of sewage discharges into the water-courses, agriculture activities and the use of the area for cattle husbandry influenced the quality of the river waters, for instance, the pH of a spring-water sample reached the value of 4.3. The São Bartolomeu Stream has been contributing to the deterioration of the water quality of the Turvo Sujo River, while the Turvo Limpo River has also been affected by anthropogenic discharges in the Turvo Sujo River. The speciation of Cd, Cu and Pb showed that these metals were mainly found in the particulate fraction (i. e., associated with the suspended material). Fifty five percent of the water samples showed labile Zn concentrations greater than that of the nonlabile Zn.     

A knowledge network to promote the use and valorization of wild food plants in the Pantanal and Cerrado,Brazil

Regional Environmental Change - The conservation and use of wild food plants should include local people in the decision-making process, and many countries have done so. However, interacting with...     

Effects of air/fuel ratio on gas emissions in a small spark-ignited non-road engine operating with different gasoline/ethanol blends

This study investigates the effects of several blends of gasoline and anhydrous ethanol on exhaust emission concentrations of carbon monoxide (CO), total hydrocarbons (HCs), and nitrogen oxides (NO_x) from a small spark-ignited non-road engine (SSINRE). Tests were carried out for different air/fuel equivalence ratios as measured by lambda (λ). A 196 cm³ single-cylinder four-stroke engine-generator operating at a constant load of 2.0 kW was used; pollutant gas concentrations were measured with an automatic analyzer similar to those typically used in vehicle inspections. The results showed that as the ethanol content of the mixture increased the concentrations of CO, HCs, and NO_x reduced by 15, 53, and 34%, respectively, for values of λ < 1 (rich mixture) and by 52, 31, and 16% for values of λ > 1 (lean mixture). Overall, addition of anhydrous ethanol to the gasoline helped to reduce emissions of the pollutant gases investigated, what contributes to photochemical smog reduction and quality of life in urban areas.     

Environmental performance evaluation of agro-industrial innovations – part 1: Ambitec-Life Cycle,a methodological approach for considering life cycle thinking

As sustainability considerations increasingly dominate the technology development debate worldwide, practical approaches to assess environmental performance of innovations have been warranted. The present study (Part 1) introduces Ambitec-Life Cycle, a method derived from Ambitec-Agro for considering life cycle thinking in the environmental performance evaluation (EPE) of agro-industrial innovations. An agro-industrial innovation case study related to residue recycling is presented, revealing steps in the product life cycle where opportunities are best for technological improvements. In Part 2 (this issue) of this study, a methodological approach for considering the environmental vulnerability of watersheds and to integrate this analysis in EPE methods is presented. This approach is applied to Ambitec-Life Cycle and to the same residue case study, allowing the identification of performance indicators with greater potential to cause impacts at the studied watersheds.     

Oxidative transformation of polybrominated diphenyl ether congeners (PBDEs) and of hydroxylated PBDEs (OH-PBDEs)

BACKGROUND, AIM, AND SCOPE: The historical and widespread use of polybrominated diphenyl ethers (PBDEs) as flame retardants in consumer products worldwide has caused PBDEs to now be regarded as pervasive environmental contaminants. Most recently, hydroxylated PBDEs (OH-PBDEs) and methoxylated PBDEs (MeO-PBDEs) have emerged as environmentally relevant due to reports of their natural production and metabolism. An important parameter for assessing the environmental impact of a chemical substance is persistence. By formulating the concept that persistence is the result of the substance's physicochemical properties and chemical reactivity, Green and Bergman have proposed a new methodology to determine the inherent persistence of a chemical. If persistence could be predicted by straightforward methods, substances with this quality could be screened out before large-scale production/manufacturing begins. To provide data to implement this concept, we have developed new methodologies to study chemical transformations through photolysis; hydrolysis, substitution, and elimination; and via oxidation. This study has focused on adapting an oxidative reaction method to be applicable to non-water soluble organic pollutants. MATERIALS AND METHODS: PBDEs and one MeO-PBDE were dissolved in tetrahydrofuran/methanol and then diluted in alkaline water. The OH-PBDEs were dissolved in alkaline water prior to reaction. The oxidation degradation reaction was performed at 50 degrees C using potassium permanganate as described elsewhere. The pH was maintained at 7.6 with disodium hydrogen phosphate and barium hydrogen phosphate, the latter also serving as a trapping agent for manganate ions. The oxidation reactions were monitored by high-performance liquid chromatography and reaction rates were calculated. RESULTS: The OH-PBDEs have very fast oxidative transformation rates compared to the PBDEs. The reaction rates seem to be primarily dependent on substitution pattern of the pi-electron-donating bromine substituents and of bromine content. There are indications that further reactions of OH-PBDEs, e.g., methylation to the MeO-PBDEs, decrease the oxidation rates, and thereby generate more persistent substances. DISCUSSION: The resistance of PBDEs to oxidation, a major degradation pathway in air, should be further investigated, since these compounds do undergo long range transport. With slight modifications, the original method has been adapted to include a larger variety of chemical substances, and preliminary data are now available on the oxidative transformation rates for PBDEs and of OH-PBDEs. CONCLUSIONS: The original oxidation degradation method can now include non-water soluble compounds. This modification, using low concentrations of test chemicals, allows us to measure oxidative transformation rates, for some of the lower brominated DEs, data that can be used to assess their persistence in future model calculations. Oxidative transformation rates for PBDEs are slow compared to those for the OH-PBDEs. This suggests that OH-PBDEs, when released into the environment, undergo faster oxidative metabolism and excretion than the PBDEs. RECOMMENDATIONS AND PERSPECTIVES: To evaluate the modified method, more degradation reactions with non-water soluble compounds should be investigated. Recent studies show that OH-PBDEs are present in rats and in humans and, because of their activity as endocrine disruptors, determining their subsequent environmental fate is of importance. The resistance of PBDEs to oxidative degradation should be acknowledged as of possible future concern. Several other compound classes (such as polychlorinated biphenyls (PCBs), hydroxylated polychlorinated biphenyls (OH-PCBs), and pharmaceuticals) need to be subjected to this screening method to increase the database of transformation rates that can be used with this model.     

Biodegradation of LDPE/Modified Starch Blends Sterilized with Gamma Radiation

Blends of LDPE/modified starch were prepared, sterilized by gamma radiation and investigated with respect to their microbial degradation by a mixture of fungal strains in liquid medium after 90 days, was analyzed by carbon dioxide (CO₂) production (Sturm test). Biodegradation of blends was evaluated by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction; mechanical testing, scanning electron microscopy (SEM). The biodegradation of LDPE/modified starch blends was attributed to microbiological attack, with alterations in the chemical structure of the blend with an increase in the carbonyl and vinyl indices and the appearance of new crystalline symmetry generating a crystalline domain not existing before in the blend and decrease in the mechanical properties.     

Solid-Phase Microextraction As A Tool for Studying Volatile Compounds in Frog Skin

Solid-phase microextraction (SPME) is an effective technique for studying frog volatile secretions. Its primary advantage is in its application to sampling live animals. the ability to sample an organism over an extended period allows changes in an individual's chemical signature to be determined. the presence of eucalyptol in the skin secretion of Ewing's tree frog, Litoria ewingi, was used to assess the effectiveness of SPME in sampling frog volatiles. Rapid sample times coupled with the polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibre provided the best signal/noise ratio for the majority of frog volatiles analysed, and importantly resulted in the least amount of stress to the animals involved.     

Suitable environmental areas for commercial timber in the state of Rio de Janeiro,Southeastern Brazil

Environment, Development and Sustainability - In state of Rio de Janeiro, the Southeast Region of Brazil, 97.91% of the reforested areas contain exclusively species of Pinus and Eucalyptus. Due to...