Four species of trees were selected to evaluate the tolerance to heavy crude oil contamination by means of a tolerance index integrating germination, height, biomass and survival as variables. Fresh seeds to Cedrela odorata (tropical cedar), Haematoxylum campechianum (tinto bush), Swietenia macrophylla (mahogany) and Tabebuia rosea (macuilis) were planted in a Vertisol to which heavy crude petroleum was added at four different treatments (C0, 0; C1, 18,940; C2, 44,000; and C3, 57,000 mg kg⁻¹), with the control being uncontaminated soil. The experiment was carried out in a greenhouse during 203 days with a completely random design. The presence of petroleum in soil stimulated and increased germination of S. macrophylla and C. odorata, accelerated the germination of T. rosea and did not affect the germination of H. campechianum. The height and biomass of all species was reduced in the presence of petroleum in the soil. The survival of S. macrophylla and H. campechianum was not affected by petroleum at any concentration studied. On the other hand, C. odorata and T. rosea showed high mortality at all concentrations. The tolerance index showed that S. macrophylla was best at tolerating petroleum in soil and could be employed as a productive alternative for the advantageous use of contaminated sites. The use of tree species could be important because of the great potential of trees for phytoremediation due to their long life, biomass and deep roots that can penetrate and remediate deeper soil layers.

This paper addresses the oxidation by ultraviolet radiation of methylparaben, a ubiquitous and suspicious preservative which is massively added to cosmetics and personal care products. Experiments included pH and temperature variation, as well as several experimental conditions such as presence/absence of hydrogen peroxide, titanium dioxide, or some different water matrix (surface water or ground water). Results were evaluated under the line source spherical emission model, so quantum yield was the adequate target variable for explaining the process. A modified Arrhenius correlation including pH level was used for modelling the whole system.

The fate and behaviour of tributyltin (TBT) at two wastewater treatment works was examined. Both sites had two inlet streams, and each utilised high rate biological filters (biofilters) on one the streams, before treatment of the combined flows on trickling filters, with one having additional tertiary processes, installed to remove ammonia and solids. The study was designed to determine if these processes enhanced the removal of TBT. Degradation of TBT was observed in one of the biofilters, possibly as a result of temperature and hydraulic loading. At the treatment works with tertiary processes, the mass flux showed the overall removal of TBT was 68 %, predominantly due to removal with solids in the primary settlement processes. However, overall removal of 95 % was observed in the conventional trickling filter works with 94 % of this due to biodegradation in the trickling filter. The two works both removed TBT, but at different treatment stages and by different processes. Differences in the form (solubility) of TBT in the influent may have attributed to this, although further understanding of factors controlling degradation would allow for a more complete assessment of the potential of biological processes to remove hazardous compounds from wastewaters.

The processes of wind erosion of fertile soil, dune movement in sand deserts, dust storms in arid and semi-arid regions, as well as the emission and dispersion of agricultural or industrial dusts create a lot of problems and dangers for human life, environment, and infrastructure. Conventional ways to suppress dust emission to the atmosphere are agricultural fixation in the case of fertile soil surface and application of chemical agents to immobilize dust particulates onto the surface of soil, desert sand, country roads, or mining areas. However, these methods are often too expensive to be applied for large-scale suppression of sand dust. Chemical methods of dust suppression are often environmentally unfriendly due to the release of toxic reagents in water, air, and soil. This paper examines, for the first time, the microbially mediated aggregation of fine sand particles to suppress the emission of sand dust and its chemical and bacteriological pollutants. The bioaggregation reagent was a solution of calcium chloride and urea sprayed over the sand surface, which was preliminarily treated with the suspension of urease-producing bacteria. Quantity of calcium used for sand dust suppression was 15.6 g of Ca/m2. After the biotreatment of fine sand, the release of sand dust and its artificial pollutants to the atmosphere decreased in comparison with control by 99.8 % for dust, 92.7 % for phenantherene, 94.4 % for led nitrate, and 99.8 % for bacterial cells of Bacillus megaterium. This immobilization of dust and dust pollutants was due to the bioaggregation of fine sand particles. The sizes of 90 % of the sand dust particles increased from 29 μm in control to 181 μm after bioaggregation. Bioaggregation treatment of the soil surface could be a useful method to prevent the dispersion of dust and dust-associated chemical and bacteriological pollutants in water, air, and soil. © 2013 Springer Science+Business Media Dordrecht.

This study aimed to chemically and radiologically characterize the water resources influenced by a phosphogypsum stack in Imbituba, SC, Brazil and to identify the annual intake by ingestion. Surface water was collected at six points downstream of the phosphogypsum stack. Subsurface water samples were collected from a piezometer in the stack area. These samples were analyzed using a radiochemical method to determine the natural radionuclide content and an inductively coupled plasma optical emission spectrometry to determine the concentration of selected metals. The concentrations of radionuclides were also compared with current standards. The radionuclide concentrations in the surface waters samples were lower or similar to those found in other studies. The effective dose resulting from water ingestion is below the recommended reference levels for drinking water. Samples collected exhibited no increase in radioactivity, under the influence of phosphogypsum stacks.

The impact of three commercially available nanoparticles (NPs) on trichloroethylene (TCE) adsorption onto granular activated carbon (GAC) was investigated. TCE adsorption isotherm and column breakthrough experiments were conducted in the presence and absence of silicon dioxide, titanium dioxide, and iron oxide nanoparticles. A rapid small-scale column test (RSSCT) was assessed for its ability to predict TCE adsorption in pilot-scale GAC in the presence and absence of NPs. Zeta potential of the three NPs and the GAC were measured. Particle size distribution of the NP dispersions was analyzed as a function of time. The surface area and the pore size distribution of the virgin and the exhausted GAC were obtained along with transmission electron microscopy and Fourier transform infrared spectroscopy analysis. The effect of NPs was found to be a function of their zeta potential, concentration, and particle size distribution. Due to their electrical charge, NPs attached to the GAC and blocked the pores and thus reduced the access to the internal pore structure. However, due to the fast adsorption kinetics of TCE, no effect from the three NPs was observed in the isotherm and kinetic studies. The RSSCT, on the other hand, accurately predicted the pilot-column TCE breakthrough in the presence of NPs.

Textile industries use large amounts of water in dyeing processes and a wide variety of synthetic dyes. A small concentration of these dyes in the environment can generate highly visible pollution and changes in aquatic ecosystems. Adsorption, biosorption, and biodegradation are the most advantageous dye removal processes. Biodegradation occurs when enzymes produced by certain microorganisms are capable of breaking down the dye molecule. To increase the efficiency of these processes, cell immobilization enables the reuse of the immobilized cells and offers a high degree of mechanical strength, allowing metabolic processes to take place under adverse conditions. The aim of the present study was to investigate the use of Saccharomyces cerevisiae immobilized in activated sugarcane bagasse for the degradation of Acid Black 48 dye in aqueous solutions. For such, sugarcane bagasse was treated with polyethyleneimine (PEI). Concentrations of a 1 % S. cerevisiae suspension were evaluated to determine cell immobilization rates. Once immobilization was established, biodegradation assays for 240 h with free and immobilized yeast in PEI-treated sugarcane bagasse were evaluated by Fourier transform infrared spectrophotometry. The results indicated a probable change in the dye molecule and the possible formation of new metabolites. Thus, S. cerevisiae immobilized in sugarcane bagasse is very attractive for biodegradation processes in the treatment of textile effluents. © 2013 Springer Science+Business Media Dordrecht.

The presence of macrolide antibiotics in aquatic environments causes serious antibiotic resistance propagation in microorganisms. In this study, the use of porous resins as adsorbents for the removal of tylosin from aqueous solutions was evaluated. The effectiveness of the resins (macroporous resin XAD-4, hypercross-linked resin MN-202, and aminated polystyrene resin MN-150) was compared with commercial hydroxylated multiwall carbon nanotubes (H-MWCNTs). Similar patterns of pH-dependent adsorption were observed despite the different surface properties and pore structures of the three resins, implying the importance of the tylosin molecular form in the adsorption process. Tylosin adsorption onto the four adsorbents showed different ionic strengths and temperature dependence consistent with the tylosin speciation and corresponding adsorption mechanism. The adsorption of tylosin onto the XAD-4 and MN-202 is mainly controlled by the intermolecular interactions between the matrix of the adsorbents and the tylosin molecule, whereas specific bonds among multiple surface functional groups are the predominant contributors to MN-150 and H-MWCNTs. The pore size is the key parameter in tylosin adsorption onto the surface of the adsorbents. The adsorption kinetics of the four adsorbents followed the pseudo-second-order model. The adsorption isotherm data well fit the Langmuir models, indicating surface coverage by a monomolecular layer.

A pot experiment was conducted in order to study the relationships of soil pollution indices to maize (Zea mays L.) growth characteristics and soil and plant heavy metal content, as well as the metal plant uptake. A completely randomized block design was used, including 11 treatments in three replications. The treatments applied were control (freshwater), four levels of inorganic NPK fertilizer combined with treated municipal wastewater and freshwater and three sludge levels (5, 25 and 50 %, respectively) in the presence of treated wastewater and freshwater, respectively. The mean effect of the applied sludge levels independent of the presence of the freshwater or wastewater contributed to the accumulation of heavy metals Cr, Cu, Zn and Mn in soil and in leaves. The soil pollution indices, i.e., pollution load index (PLI), elemental pollution index (EPI), total concentration factor and heavy metal load, showed that the soil had been polluted with heavy metals to a great extent. The application of sludge treatment affected positively the maize plant height, leaf number and the indices PLI and EPI. All pollution indices studied were positively related to plant leaf number and plant height, as well to heavy metal soil content.