Natural concentrations and reference values of heavy metals in sedimentary soils in the Brazilian Amazon

The soils of the Brazilian Amazon exhibit large geochemical diversity reflecting the different soil formation processes in an area covering 49% of the Brazilian territory. Soil contamination by heavy metals is one of the threats to the sustainability of this Biome but establishing quality reference values (QRVs) for the region is a challenging owing to the immense territorial area of the Amazon. This study aimed to determine the natural background of heavy metals in soils from the southwestern Brazilian Amazon in order to propose QRVs for Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sb, and Zn for alluvial sedimentary soils. One hundred and twenty-eight soil samples were collected at a depth of 0.0–0.2 m in sites with minimal anthropogenic interference. Soil sample digestion was based on the EPA 3051A method and metal concentrations were determined by ICP-OES. QRVs calculated for the southwestern Brazilian Amazon are among the lowest recorded in Brazil (mg kg^?1): Ba (16.5), Cd (0.1), Cr (6.9), Cu (2.8), Fe (15.4), Mn (13.4), Ni (1.7), Pb (4.4), Sb (0.9), and Zn (5.7). The low metal concentration is likely a result of the sedimentary origin of the soils. The results of this study can serve as a basis for defining public policies to investigate the environmental impacts resulting from changes in land use in areas of the Brazilian Amazon.     

Using multivariate techniques as a strategy to guide optimization projects for the surface water quality network monitoring in the Velhas river basin,Brazil

Surface water quality monitoring networks are usually deployed and rarely re-evaluated with regard to their effectiveness. In this sense, this work sought to evaluate and to guide optimization projects for the water quality monitoring network of the Velhas river basin, using multivariate statistical methods. The cluster, principal components, and factorial analyses, associated with non-parametric tests and the analysis of violation to the standards set recommended by legislation, identified the most relevant water quality parameters and monitoring sites, and evaluated the sampling frequency. Thermotolerant coliforms, total arsenic, and total phosphorus were considered the most relevant parameters for characterization of water quality in the river basin. The monitoring sites BV156, BV141, BV142, BV150, BV137, and BV153 were considered priorities for maintenance of the network. The multivariate statistical analysis showed the importance of a monthly sampling frequency, specifically the parameters considered most important.     

Dynamic Modeling of Biological Treatment of Leachates from Solid Wastes

Leachates from municipal solid wastes are liquids formed by organic and inorganic components suitable for biological treatment. In biological treatment plants, prediction of the output parameter value due to dynamic variation is essential. A dynamic model based on ASM1 has been applied for prediction of effluent COD value at real scale, using three different composition leachates. Tuning between dynamic variables and predicted parameter is tested for a correct proposal of the model. Dynamic model predicts correctly fluctuations in the output COD value and tempers dynamism caused by variation of temperature and biomass concentration in the case of high organic loaded leachates. Kinetic parameters Y _H and K _s are fixed to solve the model, and dynamic variables μ _H and X_BH are changing in time. μ_H,max is obtained in simulation (0.37–1.82 day^?1) for minimum error between predicted values and experimental data. μ_H,max value is much lower compared with the value for domestic wastewater treatment due to lower biodegradability of leachate.     

Monitoring the effectiveness of the European tributyltin regulation on the Basque coast (northern Spain) by assessing imposex in two gastropod species (Nassarius reticulatus and Nassarius nitidus)

Imposex and butyltin body burden were assessed in 2011 along the Basque coast (northern Spain) in two gastropod species (Nassarius reticulatus and Nassarius nitidus) four years after an initial survey in 2007. The aim of this re-survey was to monitor the effectiveness of the European ban on the use of tributyltin (TBT) based antifouling paints on ships’ hulls (EC 782/2003). Imposex levels in 2011 were lower than those determined in 2007 at most of the sampling sites. Accordingly, TBT concentrations in the female body burden of Nassarius reticulatus varied from 43 to 250 ng Sn/g in dry weight in 2011, which was a lower maximum than in 2007. Nevertheless, the results for the butyltin degradation index suggest that there have been recent inputs of TBT within the two main Basque harbours. Overall, the legislative measure is contributing to the reduction of TBT effects on the Basque coast although its presence is still evident.     

Biosorption of Phosphorus Using Alginate-Like Exopolymers: Investigation of Removal Mechanism,Kinetic and Thermodynamic Properties

Journal of Polymers and the Environment - The purpose of this study was to investigate the phosphorus (P) adsorption mechanism, kinetic, isothermal and thermodynamic parameters using alginate-like...     

Free-ranging dogs’ lifetime estimated by an approach for long-term survival data with dependent censoring

Environmental and Ecological Statistics - Populations of free-ranging dogs are still a matter of concern in developing countries. The presence of stray dogs is associated with environmental and...     

Effects of La2O3 nanoparticles and bulk-La2O3 on the development of Pfaffia glomerata (Spreng.) Pedersen and respective nutrient element concentration

Environmental Science and Pollution Research - Nanoparticles (NPs) have been progressively applied in the last decades, which may impact the environment. Synthesis of pigments, growing, and...     

The effects of accelerated carbonation on CO2 uptake and metal release from incineration APC residues

This work presents the results of a study on accelerated carbonation of incinerator air pollution control residues, with a particular focus on the modifications in the leaching behaviour of the ash. Aqueous carbonation experiments were carried out using 100% CO₂ at different temperatures, pressures and liquid-to-solid ratios, in order to assess their influence on process kinetics, CO₂ uptake and the leaching behaviour of major and trace elements. The ash showed a particularly high reactivity towards CO₂, owing to the abundance of calcium hydroxides phases, with a maximum CO₂ uptake of ～250 g/kg. The main effects of carbonation on trace metal leaching involved a significant decrease in mobility for Pb, Zn and Cu at high pH values, a slight change or mobilization for Cr and Sb, and no major effects on the release of As and soluble salts. Geochemical modelling of leachates indicated solubility control by different minerals after carbonation. In particular, in the stability pH range of carbonates, solubility control by a number of metal carbonates was clearly suggested by modelling results. These findings indicate that accelerated carbonation of incinerator ashes has the potential to convert trace contaminants into sparingly soluble carbonate forms, with an overall positive effect on their leaching behaviour.