Input/output budgets for cadmium (Cd), lead (Pb) and mercury (Hg) in the years 1997–2011 were monitored and determined for 14 small forest-covered catchments across Europe as part of the Integrated Monitoring program on the effects of long-range pollutants on ecosystems. Metal inputs were considered to derive from bulk deposition, throughfall and litterfall. Outputs were estimated from run-off values. Litterfall plus throughfall was taken as a measure of the total deposition of Pb and Hg (wet + dry) on the basis of evidence suggesting that, for these metals, internal circulation is negligible. The same is not true for Cd. Excluding a few sites with high discharge, between 74 and 94 % of the input Pb was retained within the catchments; significant Cd retention was also observed. High losses of Pb (>1.4 mg m⁻² year⁻¹) and Cd (>0.15 mg m⁻² year⁻¹) were observed in two mountainous Central European sites with high water discharge. All other sites had outputs below or equal to 0.36 and 0.06 mg m⁻² year⁻¹, respectively, for the two metals. Almost complete retention of Hg, 86–99 % of input, was reported in the Swedish sites. These high levels of metal retention were maintained even in the face of recent dramatic reductions in pollutant loads.

Emissions of volatile organic compounds (VOCs) were studied from three heavily polluted rivers (Huijiang, Nancun, and Zengbian Rivers) in Guangzhou, South China. A total of 49 species of VOCs were identified. Nancun River had the highest concentration of total VOCs (TVOCs), which ranged from 1,467 to 5,522 μg m⁻³. Trichloroethene, benzene, toluene, ethylbenzene, m/p-xylene, o-xylene, styrene, and 1,3,5-trimethylbenzene were the main pollutants. The levels of VOCs evaporated from the three rivers exhibited different patterns. Correlations between the concentrations of major VOCs were established and found to be statistically significant, except for o-xylene. The ratios of toluene/benzene, ethylbenzene/benzene, and xylene/benzene were estimated and found to be higher than widely reported in the literature. TVOC fluxes in the three rivers were calculated to be the range from 24.8 to 765 μg m⁻² h⁻¹. This study provides a regional background for the emission inventories of VOCs from heavily polluted rivers in southern China and provides resource managers with important information to guide remediation and policy concerning VOC emissions to the environment.

It is known that peat can be a potential adsorbent to remove contaminants from wastewaters. When raw peat is used, many limitations exist: Natural peat has a low mechanical strength, high affinity for water, poor chemical stability and tendency to shrink and/or swell. In this work, in order to obtain a more manageable substrate, to be used as adsorbent, peat was entrapped in calcium alginate beads. Box–Behnken factorial design was used to obtain the best condition for the immobilization of peat in calcium alginate beads. The independent variables studied were: peat concentration, sodium alginate concentration and calcium chloride concentration, whereas the dependent variables studied were based on the variation of colour parameters after the treatment of vinasses with entrapped peat. High colour reductions can be achieved using entrapped peat formulated by mixing 2 % of peat with 3 % of sodium alginate and pumped it on calcium chloride (0.05 M).

The characterisation of plant responses to metal exposure represents a basic step to select a plant species for phytoremediation. In the present work, 3-week-old Amaranthus paniculatus L. plants were subjected to nickel chloride concentrations of 0 (control), 25, 50, 100 and 150 μM in hydroponic solution for 1 week to evaluate morphophysiological responses, such as biomass production and partitioning, nickel accumulation in plants and nickel removal ability from the polluted solutions. The results showed a progressive decrease in plant organ dry mass with the enhancement of nickel (Ni) concentration in the solution, suggesting a good metal tolerance at 25 μM Ni and a marked sensitivity at 150 μM Ni. The modification of biomass partitioning was particularly appreciated in leaves, analysing the organ mass ratio, the total leaf area and the specific leaf area. Amaranthus plants accumulated a significant amount of Ni in roots exposed to the highest Ni concentrations, while lower metal contents were observed in the aerial organs. The Ni uptake ratio was progressively reduced in plants exposed to increased Ni concentrations. The metal translocation from root to shoots, appreciated by the Ni translocation index, showed a far lower value in Ni-exposed plants than in controls. Moreover, by measuring the daily Ni content of the solutions, a lower Ni removal ability was found in Amaranthus plants at increasing Ni concentrations. Remarkably, plants exposed to 25 μM Ni succeeded in removing almost 60 % of the initial Ni content of the solution showing no stress symptoms. The potential of A. paniculatus for phytoremediation was discussed.

Pyrite, FeS₂, is the most common sulfide mineral. The aim of this work was to assess the oxidative ability of H₂O₂ in presence of natural pyrite by employing reactive black 5, acid red GR, and cationic red X-GRL as model pollutants. The effects of H₂O₂ dosage, pyrite loading, and initial pH on reaction were investigated. The results reveal that natural pyrite-promoted H₂O₂ has a great activity in the decoloration of azo dyes. About 85 % of reactive black 5 and acid red GR can be removed within 10 min when 0.3 mM H₂O₂ and 0.3 g/L pyrite are used with initial pH values ranging from 6.32 to 6.96. The discoloration efficiencies are demonstrated to be less sensitive to the initial solution pH value. Approximately 90 % of discoloration for reactive black 5 and acid red GR can be achieved when initial pH value ranges from 2 to 10. Ion leaching experiments show that high levels of ferrous iron and sulfate can be detected when natural pyrite is added to dye solution alone. To gain an understanding of the reaction mechanism and the role of natural pyrite takes in these processes, techniques including scanning electron microscope, X-ray diffraction, and X-ray photoelectron were employed to characterize the solid sample and ion leaching experiments were also carried out. Results indicate that the determined high levels of ions have resulted from the dissolution of FeSO₄·H₂O formed on the surface of pyrite and the homogeneous Fenton reaction initiated by ferrous iron in presence of H₂O₂ is mainly responsible for the observed fast color removal rate.

Persistence and dissipation kinetics of clothianidin were studied in sandy loam soil of sugarcane ecosystem by adopting a rapid and sensitive analytical method. This single-step analytical method was observed to be superior to multi-step conventional method reported to quantify the residues of clothianidin in soil, in terms of recovery, sensitivity and rapidity besides cost-effectiveness. The recoveries of clothianidin were in the range of 93.19 ± 3.07-95.43 ± 2.09 % at 0.01-0.1 μg/g level of fortification in soil. The limit of quantification of the method was 0.01 μg/g. Dissipation pattern of clothianidin followed first-order kinetics with a good fit (R 2 > 0.96). Half-life of clothianidin was 17.2 and 17.4 days at the single (50 g a.i./ha) and double doses (100 g a.i./ha), respectively. Clothianidin was observed to be more persistent than imidacloprid and thiamethoxam in the soil of tropical sugarcane ecosystem. © 2013 Springer Science+Business Media Dordrecht.

Development of aminopolycarboxylate chelants (APCs) having enhanced biodegradability is gaining increasing focus to replace the EDTA and its homologs with those used widely for the ex situ treatment of contaminated soils and are potential eco-threats. The paper reports the chelant-assisted extraction of the toxic metals (Cd, Cu, Pb, and Zn) from the metal-spiked European reference soils (Eurosoil 1 and Eurosoil 4) using biodegradable APCs, namely EDDS, GLDA, and HIDS. The effects of chelant-to-metal molar ratio, solution pH, and metal/chelant stability constants were evaluated, and compared with that of EDTA. The selectivity aptitude of the biodegradable chelants towards the toxic metals was assumed from the speciation calculations, and a proportionate correlation was observed at neutral pH. Pre- and post-extractive solid phase distributions of the target metals were defined using the sequential extraction procedure and dissolution of metals from the theoretically immobilized fraction was witnessed. The effect of competing species (Al, Ca, Fe, Mg, and Mn) concentrations was proven to be minimized with an excess of chelant in solution. The highlight of the outcomes is the superior decontamination ability of GLDA, a biodegradable APC, at minimum chelant concentration in solution and applicability at a wide range of pH environments.

Kinetics and mechanism on discoloration of an azo dye, methyl orange (MO), by heterogeneous Fenton-like reaction using natural schorl as catalyst were investigated in this study. Among the three kinetic models (the first-order, the second-order, and the Behnajady-Modirshahla-Ghanbery (BMG)), the BMG kinetic model was the best one to describe MO discoloration at different reaction conditions, due to its highest determination coefficients. The BMG model parameter, 1/m, increased with initial hydrogen peroxide (H2O 2) concentration, and schorl dosage and reaction temperature increased while the pH solution decreased. The phenomenon indicated that the initial MO discoloration rate increased with the ascending of the initial H 2O2 concentration, schorl dosage, and reaction temperature and the descending of the pH solution. Meanwhile, another BMG parameter, 1/b, except for the one at pH=5, were all around 1, implying that the schorl-catalyzed Fenton-like reaction had high capacity for MO discoloration. The possible reason for these phenomena was interpreted from the point of view of OH generation and Fe dissolution. Generally speaking, the amount of hydroxyl radicals increased with initial H2O2 concentration, increased schorl dosage and reaction temperature, and decreased pH solution, playing an important role in the change of 1/m values. The concentration of soluble iron ions at all adopted experimental conditions ranged from 0.23 to 1.14 mg/L, much lower than the European Union directive (2 mg/L), which demonstrated that natural schorl would be a promising heterogeneous catalyst for the Fenton-like reaction. Finally, a possible mechanism for this process was put forward. © Springer Science+Business Media Dordrecht 2013.

Soil is one of the compartments most affected by the accumulation of pollutants from anthropic sources. The present study allowed the identification of the sensitivity of the Allium cepa test system to evaluate solubilized soils from two points in the area contaminated by heavy metals, as well as a point of reference. They are all located in the municipality of Triunfo, state of Rio Grande do Sul, Brazil. The parameters used for evaluation were germination index, mitotic index, chromosomal aberrations (CA), and index of mutagenicity index (IMUT) presented by A. cepa. Significant responses of CA were observed in the two samples of contaminated soil, but IMUT was significant only for soil 3. The toxicity and cytotoxicity indexes did not show significant responses. The results indicate that the A. cepa plant test system was sensitive to investigate the genotoxicity of the soil samples and can be used as an alert in studies on soil contamination. It was partially concordant with the mutagenic responses already detected for the Salmonella/microsome assay in previous studies.

The impacts of dissolved organic matter (DOM) on the removal of 17β-estradiol (E2) in horseradish peroxidase (HRP)-mediated oxidative coupling systems were investigated in this study. The results showed that the removal rate of E2 and the affinity of HRP to E2 had been significantly decreased in the presence of DOM. Compared with urban sludge DOM (USDOM), river sediment DOM (RSDOM), which features relatively low aromaticity and molecular weight and a large number of O-containing groups, more strongly inhibited the E2–HRP–H₂O₂ reactions than USDOM. The products were analyzed with electrospray ionization mass spectrometry. The results suggested that the self-coupling of E2 was suppressed in the presence of DOM, likely resulting from cross-coupling between DOM and E2 or self-coupling of DOM in the HRP system. The results are useful in understanding the fate of estrogens in natural systems.