Greenhouse gas emissions from a semi-arid tropical reservoir in northeastern Brazil

We estimated carbon dioxide (CO₂) and methane (CH₄) emissions by diffusion, ebullition, and degassing in turbines from a semi-arid hydropower reservoir in northeastern Brazil. Sampling sites were allocated within the littoral and deeper waters of one embayment, the main-stream, and at turbines. Annual carbon emissions were estimated at 2.3?×?10⁵?±?7.45?×?10⁴ t C year^?1, or in CO₂-equivalents (CO₂-eq) at 1.33?×?10⁶?±?4.5?×?10⁵ t CO₂-eq year^?1. Diffusion across the water surface was the main pathway accounting for 96% of total carbon emissions. Ebullition was limited to littoral areas. A slight accumulation of CO₂, but not of CH₄, in bottom waters close to the turbines inlet led to degassing emissions about 8?×?10³ t C year^?1. Emissions in littoral areas were higher than in main-stream and contribute to 40% of the total carbon. Carbon (C) emissions per electricity generated, at 60% of installed capacity, is 0.05 t C-CO₂-eq MWh^?1. The ratio increases to 0.09 t C-CO₂ MWh^?1, equating 80% of the emissions from natural gas and 40% of diesel or coal power plants. Retention time and benthic metabolism were identified as main drivers for carbon emissions in littoral areas, while water column mixing and rapid water flow are important factors preventing CH₄ accumulation and loss by degassing. Our results indicate that Itaparica Reservoir, located in the semi-arid region of Northeastern Brazil, acts as a source of GHGs. Management measurements are needed to prevent emissions to raise in the future.     

Social contrasts and land use conflicts in the context of sustainable development and management needs: a case study from an estuarine area at northeastern Brazil

This paper discusses the misuses of estuaries in Northeast of Brazil and the social contrasts there found. The several kinds of impacts promoted by capitalist enterprises in one side and by traditional population, who uses estuary areas at another side, are in complete disagreement with the ethic of sustainable development. Our intention is to demonstrate how these aspects occur in the River Paraíba do Norte estuary, in the State of Paraíba. Observing the conditions of infrastructure besides the multiple ways to handle along with the extension of the estuary, we could recognize 59 focus of conflict between the incorrect use and sustainable mode. Most of the uses concern to traditional artisan fishing, slums and recreational marinas, reflecting the great social contrast between rich and poor people settled in area studied. Ecological and social implications of these conflicting uses are discussed and measures to improve the situation are suggested.     

Short-term seasonal variability in Be wet deposition in a semiarid ecosystem of central Argentina

The ⁷Be wet deposition has been intensively investigated in a semiarid region at San Luis Province, Argentina. From November 2006 to May 2008, the ⁷Be content in rainwater was determined in 58 individual rain events, randomly comprising more than 50% of all individual precipitations at the sampling period. ⁷Be activity concentration in rainwater ranged from 0.7 ± 0.3 Bq l⁻¹ to 3.2 ± 0.7 Bq l⁻¹, with a mean value of 1.7 Bq l⁻¹ (sd = 0.53 Bq l⁻¹). No relationship was found between ⁷Be content in rainwater and (a) rainfall amount, (b) precipitation intensity and (c) elapsed time between events. ⁷Be ground deposition was found to be well correlated with rainfall amount (R = 0.92). For the precipitation events considered, the ⁷Be depositional fluxes ranged from 1.1 to 120 Bq m⁻², with a mean value of 32.7 Bq m⁻² (sd = 29.9 Bq m⁻²). The annual depositional flux was estimated at 1140 ± 120 Bq m⁻² y⁻¹. Assuming the same monthly deposition pattern and that the ⁷Be content in soil decreases only through radioactive decay, the seasonal variation of ⁷Be areal activity density in soil was estimated. Results of this investigation may contribute to a valuable characterization of ⁷Be input in the explored semiarid ecosystem and its potential use as tracer of environmental processes.     

Climate impact on agroeconomy in semiarid region of Armenia

With 21 % of gross domestic product (GDP) in agricultural sector and having consistently experienced natural disasters (e.g., drought, flood), Armenia is very vulnerable to climate and its change. Given the fact that 63 % of the entire land is planted with grains, this study primarily focuses on the market for wheat flour and bread. Economic welfare loss due to drought episodes is calculated using the economic data integrated with climate measures. Economic data are utilized for the period 1995–2011 (obtained from Statistical Office of Armenia) and specifically include the quantity produced and consumed of wheat flour and bread combined with mean prices, population income, GDP in the agricultural sector, GDP in the planting sector, and governmental expenditure on subsidies. Climate data include temperature and precipitation during the period 1966–2011 (obtained from National Hydrometeorological Service of Armenia). The analysis includes three main components. The first utilizes a market framework that analyzes the impact of climate on equilibrium prices and quantities as well as trade and tax effects. The second employs a logarithmic utility function to estimate the effective insurance policy for the agricultural sector using risk management strategies. Lastly, a macroeconomic model has been developed to assess the efficient sum of governmental expenditure on subsidies and irrigation during the drought episodes and during the mean climatic conditions. All three parts of the study are developed for the first time.     

Metal levels in sugar cane (Saccharum spp.) samples from an area under the influence of a municipal landfill and a medical waste treatment system in Brazil

In July 2003, duplicated samples of roots, stems and leaves of sugar cane (Saccharum spp.) were collected in 25 points of an area under direct influence of the municipal landfill site (MLS) and medical waste treatment system (MWTS) of Ribeirao Preto, S?o Paulo, Brazil. Cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), manganese (Mn), lead (Pb) and zinc (Zn) were determined by atomic absorption spectrophotometry. The following concentrations (mg/kg) were found in roots: Cd, 0.22+/-0.12; Cr, 64.3+/-48.7; Cu, 140.6+/-27.7; Hg, 0.04+/-0.02; Mn, 561.6+/-283.3; Pb, 7.9+/-2.1 and Zn, 177.4+/-64.9. For some metals, these levels are higher than the concentrations previously reported for different plants, reaching, in some cases, values that might be considered toxic for vegetables. Metal levels in stems were 80-90% of those found in roots, while the concentrations detected in leaves were significantly lower than those in roots. The present results suggest that MLS and MWTS activities might have been increasing metal concentrations in edible tissues of sugar cane grown in the area under their influence. Moreover, the traditional agricultural practices in the production of sugar cane could be also another determinant factor to reach the current metal levels. The results of this study indicate that sugar cane is a crop that is able to grow in areas where metals in soils are accumulated.     

Radioecological characterization of a uranium mining site located in a semi-arid region in Brazil

The work presents the radioecological characterization of the new Brazilian uranium mining and milling site located in a semi-arid region of the country. The process characterization demonstrated that in heap leach plants most of the 226Ra remains in the leached ore. Despite the potential higher availability of radium isotopes in the soils of the studied region the lack of precipitation in that area reduces the leaching/mobilization of the radionuclides. High 226Ra and 228Ra concentrations were found in manioc while 210Pb was significant in pasture. It was suggested that a range from 10(-3) to 10(-1) may conveniently encompass most of the transfer factors (TF) values for soil/plant systems (i.e. involving different cultures, different soils and natural radionuclides). Impacts due to aerial transportation of aerosols and radon generated in the mining were proved to be minimal and restricted to an area not greater than 15 km2. Finally, uranium complexation by carbonates was shown to be the main mechanism responding for the elevated radionuclide concentration in groundwater.     

Rural fences in agricultural landscapes and their conservation role in an area of caatinga (dryland vegetation) in Northeast Brazil

Fences are very common in rural areas, and represent important landscape elements in both tropical and temperate climate regions. In spite of their marked presence and importance, fences have been little studied, principally in Brazil. The present study examined the types of fences, the diversity of species used in their construction, as well as the diversity of their uses in a rural community in the municipality of Caruaru, Pernambuco State, northeastern Brazil. Fifty meters of fence-line in each of 50 rural properties in the community were examined, noting the diameter, height and identity of all vegetation elements used in their composition. Semi-structured interviews were also held with their builders in order to obtain information concerning fence uses. In the total of 2,500 linear meters of fence-line, 4,953 individual plant elements were identified, belonging to 51 different species. A majority of the fence elements were non-living fence posts, although the number of living posts was high. Of the total number of fence elements, 66.7% were native to the caatinga region. The large number of native species used as non-living fence posts indicates an intensive use of the caatinga vegetation and suggests the need to stimulate the use of living fence posts for conservation purposes.     

Rewilding-inspired transhumance for the restoration of semiarid silvopastoral systems in Chile

Regional Environmental Change - Nomadic pastoralism and transhumance are ancient human adaptations to the movements of large herbivores, which themselves migrate to follow favorable environmental...     

Measurements of major ion concentration in settled coarse particles and aerosols at a semiarid rural site in India

Deposition rates and deposition velocities of water-soluble ions (F, Cl, NO3, SO4, NH4, Ca, Mg, Na and K) were measured at a rural site (Gopalpura, Agra). Dry deposition samples were collected throughout the year from December 1995 to August 1997, while the aerosol samples were collected only during the winter season of 1996. Surrogate technique was used to collect the dry deposition samples, while aerosol samples were collected on PTFE membrane filter. Deposition velocities (Vd) of SO4 and NO3 are < or = 0.01 m s(-1) while Ca, Mg, Na, K, NH4, F and Cl exhibit greater than 0.01 m s(-1) Equivalent concentration ratios of K/Na, Ca/Na and Mg/Na conform with the corresponding ratios of local soil, indicating the dominant contribution of local sources. Deposition rates are maximum in winter, followed by summer and monsoon. No significant differences are found in dry deposition rates of all ions or in atmospheric concentrations of soil-derived elements with respect to wind direction. However, in aerosols, concentrations of F, Cl, NO3 and SO4 are higher with winds from southwesterly and westerly directions corresponding to pollution sources located in these directions. Deposition data have been used to calculate the critical load of S and N for soil with respect to Triticum vulgaris. The critical load of actual acidity was found to be 622.4 eq ha(-1) year(-1) within the range of 500-1,000 eq ha(-1) year(-1) as assessed by the RAINS-Asia model for this region. The present load of S and N (77.4 and 86.4 eq ha(-1) year(-1)) was much lower than the critical load of S and N (622.4 and 2,000 eq ha(-1) year(-1)), indicating that at present there is no harmful effect on ecosystem structure and function.     

Nonformal environmental education: a case study with farmers in a town of the South Minas Gerais state,Brazil

Brazil is a central place in the international agricultural markets and this fact has been demanding environmentally oriented agricultural practices by Brazilian farmers and professionals involved in the agricultural market chain. A concise and structured questionnaire was applied to obtain the environmental perception of a group of Brazilian farmers in a town of the south Minas Gerais state, using herbicides as the topic for a case study. A highly variable opinion about taking the environment into account when choosing the most appropriate herbicide was found. Anyway, efficacy has been indicated as the most important factor when choosing an herbicide, followed by the environment and price. The outcomes from the questionnaires, i.e. the insufficient conception and importance given to environment when choosing the herbicide, motivated the creation of a teaching-learning model for the nonformal environmental education using the concept of socio-ecological resilience. This routine puts in practice the resilience thinking currently invoked as a major tool to achieve the conservation of the socio-ecological system, as well as it is complimentary to the outcome-oriented optimization for conservation theory. For the case study about farmers and the use of herbicides, we conclude that a complex reasoning and, ultimately, pro-environmental actions can be improved after experiencing the recommended model for environmental education.     

An ecohydrological adaptive approach to a salt lake in the semiarid grasslands of Argentina: future management perspectives

Past extreme hydrological events, future climate change scenarios and approaches for lake management were studied in the Argentinean Pampa. Anthropogenic climate change will impact water bodies and create enormous challenges for water management. Adaptation strategies are needed urgently to deal with the uncertainties originated by climate change on inland or coastal basins. Only a few studies have addressed practical strategies to mitigate global change impacts on lakes and practically none in South America. The purpose of this work was to discuss management options and seek better adaptive alternatives for the nature reserve Lake Chasicó, and to propose future management experiments and actions at a regional level. The ecohydrological approach is likely to increase the ecological resilience of the lake, dampen climate-driven hydrological variations and reduce eutrophication problems. Future projects should include wetland creation, fish management, water quality control, engineering work studies and education programs. Ecohydrology as an integrative natural science should be considered as a water management strategy to build ecological resilience into water bodies. The building of social-ecological resilience is also crucial for the stability of coupled human-ecological systems. The integration of natural and social sciences into sustainability approaches represents a robust strategy for adapting to climate change.     

Multi-scale land cover dynamics of semiarid scrubland in Baja California,Mexico

Land use and cover changes trigger multi-factorial responses with tangible and intangible effects. Driving forces governing changes are scale-, place- and time-dependent; because of their complexity, a multi-scalar analysis is required to determine conjoint causation. Studies using multi-scalar approach in semiarid scrubland ecosystems are scanty. This paper investigates land use changes on the largest semiarid scrubland ecosystem of Mexico, the Baja California Peninsula, using a multi-scalar analysis approach. It further provides insight into the likely underlying causes for land use trends. Multi-temporal databases were compiled for 1978, 1990, 2000 and 2003 from various sources; population was projected for the same years. Land cover processes were validated through intensive fieldwork. Map overlapping with the aid of geographic information systems allowed computation of land cover transformation rates. New algorithms were developed to better understand land cover trends. Multi-variate analysis was also performed to provide a synthetic statistical overview. Results showed that land cover change occurred at different times, at variable scales, due to distinct drivers. As a consequence, the current regional scenario has been shaped by distinguishable socio-economic changes. The semiarid scrubland ecosystems in the Baja California Peninsula experienced contrasting trends detectable only at site and local scales. Regionally, the replacement of original vegetation (scrubland) for other land cover category is following trends similar to those in the rest of Mexico and most semiarid ecosystems worldwide. These findings support the hypothesis that land use and cover changes must be analyzed at different times and scales to deeply understand underlying forces.     

Ecological state of peat plateaus in northeastern European Russia

An integrated assessment of the ecological state and stability of permafrost peat plateaus in northeastern European Russia has been performed with regard to current climate changes. Analytical studies have revealed heterogeneity in the composition and properties of peat organic matter in active and permafrost layers. Permafrost organic matter in peatlands is relatively undecomposed, and, theoretically, its rapid mineralization can begin upon peat thawing. Organic carbon in peatlands has not been frozen or conserved during about 64–78% of their total lifetime; therefore, it is the existence of anaerobic conditions (rather than of permafrost) that has been the most important factor for peat accumulation. Current degradation of permafrost peat plateaus is caused mainly by wind and thermal erosion but practically does not lead to the development of thermokarst. Regardless of current climate warming, peat plateaus under natural conditions (not altered by human activities) are stable ecological systems.     

Sediment budgets and source determinations using fallout Cesium-137 in a semiarid rangeland watershed,Arizona, USA

Analysis of soil redistribution and sediment sources in semiarid and arid watersheds provides information for implementing management practices to improve rangeland conditions and reduce sediment loads to streams. The purpose of this research was to develop sediment budgets and identify potential sediment sources using ¹³⁷Cs and other soil properties in a series of small semiarid subwatersheds on the USDA ARS Walnut Gulch Experimental Watershed near Tombstone, Arizona, USA. Soils were sampled in a grid pattern on two small subwatersheds and along transects associated with soils and geomorphology on six larger subwatersheds. Soil samples were analyzed for ¹³⁷Cs and selected physical and chemical properties (i.e., bulk density, rocks, particle size, soil organic carbon). Suspended sediment samples collected at measuring flume sites on the Walnut Gulch Experimental Watershed were also analyzed for these properties. Soil redistribution measured using ¹³⁷Cs inventories for a small shrub-dominated subwatershed and a small grass-dominated subwatershed found eroding areas in these subwatersheds were losing −5.6 and −3.2 t ha⁻¹ yr⁻¹, respectively; however, a sediment budget for each of these subwatersheds, including depositional areas, found net soil loss to be −4.3 t ha⁻¹ yr⁻¹ from the shrub-dominated subwatershed and −0.1 t ha⁻¹ yr⁻¹ from the grass-dominated subwatershed. Generally, the suspended sediment collected at the flumes of the six other subwatersheds was enriched in silt and clay. Using a mixing model to determine sediment source indicated that shrub-dominated subwatersheds were contributing most of the suspended sediment that was measured at the outlet flume of the Walnut Gulch Experimental Watershed. The two methodologies (sediment budgets and sediment source analyses) indicate that shrub-dominated systems provide more suspended sediment to the stream systems. The sediment budget studies also suggest that sediment yields measured at the outlet of a watershed may be a poor indicator of actual soil redistribution rates within these semiarid watersheds. Management of these semiarid rangelands must consider techniques that will protect grass-dominated areas from shrub invasion to improve rangeland conditions.     

An integrative negotiation model to deal with conflicts toward water resources management: a case study in Brazil

Environment, Development and Sustainability - An integrative negotiation model is proposed so that watershed committees (WSC) can deal better with conflicts over alternatives for protecting water...     

Assessment of plastic lumber production in Brazil as a substitute for natural wood

Environment, Development and Sustainability - This review aimed to analyze plastic lumber manufacturing in Brazil, a country with a large amount of natural wood, and devise strategies to boost...     

Impact of a small city on the structure of small mammal fauna in forests of the northeastern Moscow region

Forests in and around the reserve located near the city of Chernogolovka (50 km northeast of Moscow), forests adjoining the city, and urban forests were examined during the period from 1992 to 2004. Differences between forests of the reserve proved to be less significant than those resulting from the impact of urban factors. The influence of a small city was found to change the structure of communities of small mammals in surrounding forests by reducing their diversity and enhancing the dominance of ecologically restrained synanthropic species.     

Seasonal changes in radon concentrations in buildings in the region of northeastern Poland

In this study, seasonal observations of radon concentration changes inside buildings carried out in the northeastern region of Poland is presented. One-year measurements of radon concentrations were performed in chosen buildings. The integral method of Cr-39 trace detectors in diffusive chambers was used. Mean values of radon concentrations were determined in monthly, 2-, 3-, 6-month, and annual observations. The fraction of a mean annual concentration of the value obtained in a shorter observation was calculated. Monthly concentration values were from about 0.2 to 14.9 of the annual mean. All buildings revealed seasonal fluctuation of radon concentration. Negative correlation of indoor radon concentration in the buildings and the mean temperature outside was observed in most examined buildings. The lowest coefficient range, determining which part of the annual mean value would be obtained in the 6-month observation, was gained for exposure begun in April or October.     

Geochemical speciation of heavy metals in semiarid soils of the central Ebro Valley (Spain)

This study describes the chemical speciation of Fe, Mn, Zn and Cr in four selected soil types representative of the more abundant agricultural soils in the central Ebro river valley in Aragón. Gypsisols, Calcisols, Solonchaks and Solonetzs represent around 20% of the total soil surface in the region. A total of 12 selected sites have been sampled and five subsamples were taken in each site to create a composite sample. The four elements have been analysed by the sequential extraction procedure of Tessier et al. [Anal. Chem. 51 (1979) 844.] by emission atomic spectrometry of solid state (ICP OES). Very little amounts of Fe and Mn were retrieved from the exchangeable phase, the ready available for biogeochemistry cycles in the ecosystems. Therefore, low quantities of Fe and Mn can be taken up by plants in these alkaline soils. Cr was not detected in the bioavailable forms as well as Zn that was only present in negligible amounts in very few samples. The absence of mobile forms of Cr in all soils eliminates the toxic risk both in the trophic chain and from its migration downwards the soil profile. The largest contents of Fe, Zn and Cr were retrieved from the residual phase where metals are strongly bound to minerals, whereas Mn from the carbonate and oxide phases amounts 80% of its total content. Gypsisols and Calcisols have the lowest metal contents while the highest are found in Solonetzs and Solonchaks.     

Exposure of workers in mineral processing industries in Brazil

The mining, milling and processing of uranium and thorium bearing minerals may result in radiation doses to workers. A preliminary survey pilot program, that included six mines in Brazil (two coal mines, one niobium mine, one nickel mine, one gold mine and one phosphate mine), was launched in order to determine the need to control the radioactive exposure of the mine-workers. Our survey consisted of the collection and analysis of urine samples, complemented by feces and air samples. The concentrations of uranium, thorium and polonium were measured in these samples and compared to background data from family members of the workers living in the same dwelling and from residents from the general population of Rio de Janeiro. The results from the coal mines indicated that the inhalation of radon progeny may be a source of occupational exposure. The workers from the nickel, gold and phosphate mines that were visited do not require a program to control internal radiological doses. The niobium mine results showed that in some areas of the industry exposure to thorium and uranium might occur.