Optimizing the molarity of a EDTA washing solution for saturated-soil remediation of trace metal contaminated soils

Three experiments were conducted to optimize the use of ethylenediaminetetraacetic acid (EDTA) for reclaiming urban soils contaminated with trace metals. As compared to Na(2)EDTA, (NH(4))(2)EDTA extracted 60% more Zn and equivalent amounts of Cd, Cu and Pb from a sandy loam. When successively saturating and draining loamy sand columns during a washing cycle, which submerged it once with a (NH(4))(2)EDTA wash and four times with deionised water, the post-wash rinses largely contributed to the total cumulative extraction of Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn. Both the washing solution and the deionised water rinses were added in a 2:5 liquid to soil (L:S) weight ratio. For equal amounts of EDTA, concentrating the washing solution and applying it and the ensuing rinses in a smaller 1:5 L:S weight ratio, instead of a 2:5 L:S weight ratio, increased the extraction of targeted Cr, Cu, Ni, Pb and Zn.     

Evaluation of concrete incorporating bottom ash as a natural aggregates replacement

A study on the incorporation of coal bottom ash from thermoelectric power stations as a substitute material for natural sand in the production of concrete is here presented. The normally coarse, fused, glassy texture of bottom ash makes it an ideal substitute for natural aggregates. The use of bottom ash in concrete presents several technical challenges: the physical and mineralogical characteristics of the bottom ash; the effect on water demand and the participation on cements hydratation. In the production of the concrete, substitutions in volume were used. Two different ways to employ bottom ash were used to make up the mix proportions: one considering the natural humidity present in the porous particles and the other not considering it, seeking to maintain the same strength. These considerations are fundamental given that the process of bottom ash extraction is carried out through moisture. Mechanical tests by compressive strength were performed and the elastic modulus was determined. An analysis of the influence of bottom ash in the formation of pores was carried out through tests for the water loss by air drying and water uptake by capillary absorption. The results show that the higher the bottom ash contents in the concrete, the worse the performance regarding moisture transport. However, for one bottom ash concrete type, the mechanical properties were maintained.     

Sustainable Use of the Tropical Rain Forest: Evidence from the Avifauna in a Shifting-Cultivation Habitat Mosaic in the Colombian Amazon

We carried out a one-year study of the avifauna along a regeneration gradient created by indigenous shifting cultivation in the Colombian Amazon rain forest. Regenerating one-hectare crop fields, from 1 to 17 years after abandonment, and undisturbed understory sites were compared in a sample effort of 4323 net hours. We made 878 captures of 103 species belonging to 11 trophic groups. Differences in species richness and number of individuals captured between regenerating areas and primary forest were low. A comparison of similarity indices among the sites for each habitat type showed no consistent differences, suggesting similar levels of local heterogeneity. Similarity indices calculated between sites of different-aged habitats, however, showed that young secondary growth at less than 10 years of abandonment was least similar to other sites, whereas old secondary growth between 13 to 17 years of abandonment, and forest understories, had the most similar avifauna. Two trophic groups were absent from the samples of the forest interior, and the abundance of the other nine varied among sites of regeneration. We conclude that slash and burn agriculture represents a high-intensity, small-magnitude disturbance to the forest avifauna. Large changes occur when the crop field is established and last until about 10 years after abandonment. Our data suggest that abandoned crop fields older than this age mimic the natural patch dynamics of the forest, making this type of agriculture an example of a potentially sustainable use of tropical forests, at least from the standpoint of its impact on bird communities.     

Funneliformis mosseae and Invasion by Exotic Legumes in a Brazilian Tropical Seasonal Dry Forest

Russian Journal of Ecology - Parkinsonia aculeata and Prosopis juliflora are two of the most problematic invasive plant species in the Brazilian tropical seasonal dry forest, but the mechanisms...     

A comparison study of aerosol emissions sources in two receptor sites in Salvador (Brazil) city

Total suspended particles (TSP) and metal concentrations were determined in Salvador, Bahia, Brazil at two sites: a residential area and a residential‐commercial‐industrial neighborhood. The determined metals associated with atmospheric aerosols include Al, Ca, Cr, Cd, Fe, Mg, Mn, V, Zn and Na. Factor analysis was employed to identify the major atmospheric deposition sources. At one site the data were best represented by two sources: resuspended soil + marine aerosol and vehicular emissions, which represents 93% of the total system variance. In the second one the data were best represented by three sources: resuspended soil, metallurgy and building construction, which represents 79% of the total system variance.     

Occurrence of tar balls on the beaches of Fernando de Noronha Island,South Equatorial Atlantic

This work reports on the widespread occurrence of tar balls on a pebble beach of Sueste Bay on Fernando de Noronha Island, a Brazilian national marine park and a preserve in the South Equatorial Atlantic. Environmental regulations preclude regular visitors to the Sueste Bay beach, and the bay is a pristine area without any possible or potential sources of petroleum in the coastal zone. In this work, these tar balls were observed for the first time as they occurred as envelopes around beach pebbles. They are black in color, very hard, have a shell and coral fragment armor, and range in average size from 2 to 6 cm. The shape of the majority of the tar balls is spherical, but some can also be flattened ellipsoids. The polycyclic aromatic hydrocarbon analyses of the collected samples revealed the characteristics of a strongly weathered material, where only the most persistent compounds were detected: chrysene, benzo(b,k)fluoranthene, dibenzo(a,h)antracene and benzo(a)pyrene.     

Novel Whey Protein Isolate/Polyvinyl Biocomposite for Packaging: Improvement of Mechanical and Water Barrier Properties by Incorporation of Nano-silica

Journal of Polymers and the Environment - The current global proposal for withdrawing polymers with high resistance to degradation and from fossil sources from disposable appliances, as well as the...     

Effect of the Prestige oil spill on salt marsh soils on the coast of Galicia (northwestern Spain)

At four estuarine sites on the coast of Galicia (northwestern Spain), all of which were affected by the Prestige oil spill, soil samples were taken from polluted and unpolluted areas and their petroleum hydrocarbon contents, heavy metal contents, and other chemical and physical characteristics were measured. Oil pollution altered both chemical and physical soil properties, aggregating soil particles in plaques, lowering porosity, and increasing resistance to penetration and hydrophobicity. The chromium, nickel, copper, iron, lead, and vanadium contents of polluted soils were between 2 and 2500 times higher than those of their unpolluted counterparts and the background concentrations in Galician coastal sediments. In the cases of Cr, Cu, Ni, Pb, and V, their origin in the polluting oil was corroborated by the high correlation (r >/= 0.74) between the concentrations of these metals and the total petroleum hydrocarbon (TPH) content of the polluted soils. Soil redox potentials ranged from -19 to -114 mV in polluted soils and 112 to 164 mV in unpolluted soils, and were negatively correlated with TPH content (p < 0.01). The low values in the polluted soils explain why the soluble fractions of their total heavy metal contents were very small (generally less than 3%, and in many cases undetectable).     

Road traffic injury in sub-Saharan African countries: A systematic review and summary of observational studies

Objective: The aim of this study is to evaluate, through a systematic review of hospital-based studies, the proportion of road traffic injuries and fatalities in sub-Saharan Africa (SSA).

Methods: In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology guidelines, we searched the following electronic databases: PubMed, Embase, Africa-Wide Information, Global Health, and Web of Science. Articles were eligible if they measured proportion of road traffic injuries (RTIs) in SSA by using hospital-based studies. In addition, a reference and citation analysis was conducted as well as a data quality assessment.

Results: Up to 2015, there were a total of 83 hospital-based epidemiologic studies, including 310,660 trauma patients and 99,751 RTI cases, in 13 SSA countries. The median proportion of RTIs among trauma patients was 32% (4 to 91%), of which the median proportion of death for the included articles was 5% (0.3 to 41%).

Conclusion: The number of studies evaluating RTI proportions and fatalities in SSA countries is increasing but without the exponential rise expected from World Health Organization calls for research during the Decade of Action for Road Traffic Injuries. Further research infrastructure including standardization of taxonomy, definitions, and data reporting measures, as well as funding, would allow for improved cross-country comparisons.