It was found that some of the medicinal plants accumulate increased amounts of toxic elements like Cd or Pb. Less is known about the accumulation of other hazardous elements like arsenic (As) and antimony (Sb) in these species. The present paper investigated selected medicinal plants naturally growing on old mining sites in Slovakia, Central Europe, contaminated by As and Sb. Both these elements are nonessential for plants and, in higher level, might be phytotoxic. The soil concentration of As and Sb at three different localities extensively used for mining of Sb ores in former times highly exceed values characteristic for noncontaminated substrates and ranged between 146 and 540 mg kg⁻¹ for As and 525 and 4,463 mg kg⁻¹ for Sb. Extraction experiments of soils show differences between As and Sb leaching, as the highest amount of mobile As was released in acetic acid while Sb was predominantly released in distilled water. In total, seven different plant species were investigated (Fragaria vesca, Taraxacum officinale, Tussilago farfara, Plantago major, Veronica officinalis, Plantago media, and Primula elatior), and the concentration of investigated elements in shoot ranged between 1 and 519 mg kg⁻¹ for As and 10 and 920 mg kg⁻¹ for Sb. Differences in the bioaccumulation of As and Sb as well as in the translocation of these elements from root to shoot within the same species growing on different localities have been found. This indicate that efficiency of As and Sb uptake might vary between individual plants of the same species on different sites. Increased bioaccumulation of As and Sb in biomass of investigated plants might be dangerous for human when used for traditional medicinal purposes.

We study the adsorption and desorption of chromium on two soils (a forest soil and a vineyard soil), both individually or after being combined with ground mussel shell, and on various materials (mussel shell, pyritic material from a dump site, and slate processing fines). The adsorption capacity depends mainly on the initial Cr concentration, on the pH, and on the abundance of noncrystalline Fe. The highest adsorption percentage (94 %) corresponds to the pyritic material, which also shows very low desorption rates (1.4 %), has the lowest pH, and has the highest concentration of noncrystalline Fe. The adsorption isotherms in most cases fit the Freundlich and Lineal models, rather than the Langmuir model, with no easily predictable maximum for chromium adsorption.

The performance of the Purolite A847 weak basic anion exchanger in the simultaneous removal of the azo dye Lanasyn Navy M-DNL (LNCr) and the phthalocyanine dye Acid Blue 249 (CuPc) from acidic aqueous solutions was studied under dynamic conditions. The comparison of FTIR spectra of unloaded and dye-loaded anion exchangers made it possible to consider suitable sorption mechanisms. The results of dynamic experiments revealed that anion exchanger had a greater dynamic sorption capacity with a longer breakthrough time and a shorter length of mass transfer zone when both dyes LNCr and CuPc were removed from the one-component solution as compared to those of their mixture. Models of Wolborska and Juang were found to be suitable to predict the character of breakthrough curves and to determine the characteristic parameters of the Purolite A847 column useful for process design: the mass transfer coefficient β (1/min) and time at the break point τ (minutes). The result would be useful in the design of wastewater treatment plants for removal of azo and phthalocyanine dyes from aqueous solutions and water recycling.

Spatial accuracy of hydrologic modeling inputs influences the output from hydrologic models. A pertinent question is to know the optimal level of soil sampling or how many soil samples are needed for model input, in order to improve model predictions. In this study, measured soil properties were clustered into five different configurations as inputs to the Soil and Water Assessment Tool (SWAT) simulation of the Castor River watershed (11-km² area) in southern Quebec, Canada. SWAT is a process-based model that predicts the impacts of climate and land use management on water yield, sediment, and nutrient fluxes. SWAT requires geographical information system inputs such as the digital elevation model as well as soil and land use maps. Mean values of soil properties are used in soil polygons (soil series); thus, the spatial variability of these properties is neglected. The primary objective of this study was to quantify the impacts of spatial variability of soil properties on the prediction of runoff, sediment, and total phosphorus using SWAT. The spatial clustering of the measured soil properties was undertaken using the regionalized with dynamically constrained agglomerative clustering and partitioning method. Measured soil data were clustered into 5, 10, 15, 20, and 24 heterogeneous regions. Soil data from the Castor watershed which have been used in previous studies was also set up and termed “Reference”. Overall, there was no significant difference in runoff simulation across the five configurations including the reference. This may be attributable to SWAT's use of the soil conservation service curve number method in flow simulation. Therefore having high spatial resolution inputs for soil data may not necessarily improve predictions when they are used in hydrologic modeling.

Adsorption of fluoroquinolone antibiotics using sludge-derived biochar made of various wastewater sludges was investigated. The sludge-derived biochar had relatively large Brunauer–Emmet–Teller specific surface areas that were beyond 110.0 m² g⁻¹ except the biochar made from the sludge collected from traditional sludge drying bed. The mesopore capacity was more than 57 % of the total pore capacity of all sludge-derived biochar except that made from the sludge dried through traditional sludge drying bed technique. High adsorption capacity of sludge-derived biochar was observed with a highest adsorption capacity of 19.80 ± 0.40 mg g⁻¹. High correlation between the adsorption capacity of sludge-derived biochar and the volatile content in the sludge source was observed. The Freundlich model (r ² values were in the range of 0.961–0.998) yielded the best fit with the experimental data of all the produced biochar. Fluoroquinolone antibiotics were readily adsorbed onto sludge-derived biochar. These findings suggest a new approach for the pollution control of fluoroquinolone antibiotics using low-cost sludge-derived biochar.

The present study consisted of an in vitro experiment based on columns to restore a soil affected by the tsunami of 27 February 2010 that struck the Coliumo District, Bio-Bio region, Chile. The agricultural productivity of many coastal lands was severely affected, rendering them unfit for crop production. Composite soil samples were taken at 0 to 20 cm soil depth in Coliumo, Bio-Bio region. The initial physical and chemical analysis showed textural changes, low pH, high levels of electrical conductivity (EC), sodium (Na⁺), and sulfate (SO₄²⁻), whereas bioassay tests showed severe toxicity for lettuce (Lactuca sativa L.) seeds. Germination index (GI), length of hypocotyl (LH), and length of radicle (LR) were used as indicators in the bioassay tests. Two different treatments were used: T1 = soil amended with 7.7 t ha⁻¹ of limestone (CaCO₃) and T2 = soil amended with 7.7 t ha⁻¹ of gypsum (CaSO₄). A control treatment (T0) with unamended soil was included. Each treatment received a total of 1,100 mm of clean water (4 water loads, 275 mm each), which was equivalent to the mean annual precipitation of the area studied. The T2 treatment produced a significant decrease in the concentration of Na⁺ (8.27 to 0.16 meq L⁻¹), decreased EC (1.58 to 0.03 dS m⁻¹), and increased pH from 4.83 to 6.27 in the soil under study. Leaching of Na⁺ and SO₄²⁻ with successive water loads was effective in the soil. The bioindicators as GI, LH and LR revealed that T2 was more effective than T1 and control in removing Na and SO₄ analytes from the soil matrix. The CaSO₄ amendment showed good potential for seed development, but further research on plant growth to maturity is required to determine yield parameters in the affected area.

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.

Arsenic (As) toxicity and the effects of nitric oxide (NO), supplied as sodium nitroprusside (SNP), were analyzed in Pistia stratiotes. The plants, which were grown in nutrient solution at pH 6.5, were exposed to four treatments for 24 h: control; SNP (0.1 mg L-1); As (1.5 mg L-1); and As + SNP (1.5 and 0.1 mg L-1). As accumulated primarily in the roots, indicating the low translocation factor of P. stratiotes. The As accumulation triggered a series of changes with increasing production of reactive oxygen intermediates and damage to cell membranes. The application of SNP was able to mitigate the harmful effects of As. This attenuation was probably due to the action of the SNP as an antioxidant, reducing the superoxide anion concentration, and as a signaling agent. Acting as a signal transducer, SNP increased the activity of enzymatic antioxidants (POX, CAT, and APX) in the leaves and stimulated the entire phytochelatins biosynthetic pathway in the roots (increased sulfate uptake and synthesis of amino acids, non-proteinthiols, and phytochelatins). The As also stimulated the phytochelatins biosynthesis, but this effect was limited, probably because plants exposed only to pollutant showed small increments in the sulfate uptake. Thus, NO also may be involved in gene regulation of sulfate carriers. © 2013 Springer Science+Business Media Dordrecht.

Poised to gain insight into nitrate adsorption and removal processes from water through employment of modified surfaces, a well-defined inorganic manganese species was used in connection with hydrophobic mesoporous silica. To this end, the surface of hydrophobic mesoporous silica was modified by coating silica with a manganese oxychloride (Mn₈O₁₀Cl₃) nanoparticle layer. A sol–gel method was utilized for the synthesis of hydrophobic silica, using tetraethyl orthosilicate–methyl triethoxysilane (TEOS–MTES) as precursors. Subsequent coating with Mn₈O₁₀Cl₃ took place by mixing MnCl₂ and NaOH with hydrophobic silica. Physicochemical characterization of the Mn₈O₁₀Cl₃-coated silica was carried out by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N₂ sorption. The achieved surface modification reduced remarkably the specific surface area by 80.7 % and influenced the ability of nitrates to adsorb on Mn-modified silica. Nitrate adsorption kinetics on Mn₈O₁₀Cl₃-coated silica was studied by a batch reactor. Process parameters including pH, temperature, and initial nitrate concentration were examined thoroughly. The experimental adsorption data were fitted satisfactorily through Langmuir isotherm equations and were found to be well-represented by a pseudo-second-order kinetic model. The collective data emphasize the significance of well-defined inorganic manganese phases, coating hydrophobic silica, in optimally influencing water decontamination from pollutant nitrates.