Microbial processes have shown promise for the remediation of uranium and nitrate in groundwater impacted by uranium mine tailings. This study investigated the inhibitory impact of uranium(VI) towards different microbial populations in anaerobic biofilms, including methanogenic, denitrifying, and uranium-reducing microorganisms, which are commonly found at uranium bioremediation sites. Results of batch activity bioassays indicated a very distinct level of toxicity depending on the targeted microbial community. U(VI) caused severe inhibition of acetoclastic methanogenesis as indicated by a 50 % inhibiting concentration (IC₅₀) of only 0.16 mM. Denitrifying populations were also impacted by uranium, but their sensitivity depended on the electron donor utilized. Sulfur-oxidizing denitrifiers were the least affected (IC₅₀ for denitrification activity = 0.32 mM), followed by H₂- and acetate-utilizing denitrifiers (IC₅₀ of 0.20 and 0.15 mM, respectively). In contrast, exposure to U(VI) concentrations up to 1.0 mM did not inhibit the rate of U(VI) bioreduction with H₂ as electron donor in the presence or absence of nitrate. On the contrary, a considerable increase in the uranium-reducing activity of the denitrifying and methanogenic mixed cultures was observed with increasing uranium concentrations. The results suggest that microorganisms responsible for U(V) reduction could tolerate much higher uranium concentrations compared to the other microbial populations assayed.

Water monitoring results of the Danjiangkou Reservoir indicated that total nitrogen and total phosphorus concentrations are high and therefore worse than required for central drinking water supplies. Nutrients including nitrogen and phosphorus accumulated in the bank cultivated land were greater than those contained within the river estuary sediment as well as in the reservoir bay sediment. This implies that high concentrations of loosely exchangeable phosphorus (166.53 mg/kg) in cultivated land could, after the completion of the dam heightening project, easily lead to the development of algal blooms. Serious water and soil loss occurring in the reservoir area will promote the transportation of non-point source pollution mainly caused by untreated agricultural domestic wastewater, chemical fertilizer and livestock farming, which accounted for more than 50% of the total basin’s nutrient input loads. Ecological control techniques were therefore the first choice for nutrient reduction and water quality guarantee in the Danjiangkou Reservoir. In order to guide the ecological restoration process, leading international ecological methodologies were summarized and compared, taking into consideration aspects of engineering, as well as ecological, biological, environmental and economic advantages and disadvantages. Finally, novel ecological filtration and a purification dam were designed for eutrophication control.

The decolorization of the recalcitrant dye Remazol Brilliant Blue R (RBBR) by the culture filtrate of Polyporus sp. S133 and the effect of various environmental factors were investigated. Both biodegradation and biosorption were playing an important role in bioremoval mechanisms. The highest biosorption of RBBR in Polyporus sp. S133 was shown by all carbon sources such as sucrose, glucose, fructose, and starch. No biosorption was shown by the addition of aromatic compounds and metal ions; 97.1 % RBBR decolorization was achieved in 120-rpm culture for 96 h, as compared to 49.5 % decolorization in stationary culture. Increasing the shaking rotation of the culture to more than 120 rpm was proven to give a negative effect on decolorization. The highest production of laccase was shown at pH 4 and constantly decreases when the pH level increases. The addition of glucose, ammonium tartrate, Cu²⁺, and protocatechuic acid was the suitable environmental condition for RBBR decolorization. There was a positive relationship between all environmental conditions and laccase production in the decolorization of RBBR.

This paper describes the use of dry free hanging filters, as passive samplers to determine ozone in the ambient air. The filters, with a diameter of 25 mm, were impregnated with 5,5′-disodium indigo disulphonate (IDS), a reagent for ozone. From the amount of reacted indigo compound, found on the filter, and the ozone concentration in the ambient air, a pseudo rate constant k ₁, of the reaction between ozone (O₃) and IDS on the filter, is calculated. The range of measurement is between 9 and 205 μg/m³ ambient ozone. The dry filter method is specific for ozone, while the Dutch standard method NEN2789, based on an aqueous solution of IDS, has to be corrected for the presence of NO ₓ . From wind tunnel and field experiments, k ₁ proved to vary between 0.7 and 1.5 × 10⁻⁶ m³ s⁻¹ (μg O₃)⁻¹ at wind velocities between 1 and 3 m/s and at an exposure time of 60 min. Within these conditions, ozone concentrations have been determined with free hanging filters in four busy streets in Yogyakarta, Indonesia and at two background sites using an average value of k ₁ of 1.2 × 10⁻⁶. Subsequently, the traffic NO emission was estimated from the difference of the O₃ concentrations at both sides of a road. For an arbitrary situation, an NO emission of 255 μg/s per metre road length was calculated. The filter method is inexpensive and practical, needs no electricity, is easily assembled and can be used to perform measurements in remote areas. It is shown here that this simple measurement technique may support air quality studies, e.g., in developing countries.

Concentrated Animal Feeding Operation activities lead to soil degradation in vicinity with the livestock breeding facilities, mainly due to ammonia emissions from the various stages of the process. In this research, the soil degradation effects of an intensive hog farming operation (IHFO) located at a Mediterranean limestone soil coastal area, have been investigated. Soil samples of the upper mineral soil were taken in various distances (10–1,500 m) and directions from the IHFO boundaries. Thirteen experimental cycles were carried out in the duration of 1.5 years starting in March 2009 until October 2010. The soil samples were analysed on total, exchangeable and water-soluble Al, Fe and Mn. Significantly higher concentrations of the exchangeable and water-soluble Al, Fe and Mn were observed on soil samples at increasing proximity downwind from the farm (south). Southern soil average concentrations of exchangeable Al³⁺, Fe³⁺ and Mn²⁺ ranged between 3.56 and 7.45 mmol Al³⁺ kg⁻¹ soil, 5.85 and 7.11 mmol Fe³⁺ kg⁻¹ soil and 2.36 and 5.03 mmol Mn²⁺ kg⁻¹ soil, respectively. Southern soil average concentrations of water-soluble Al, Fe and Mn forms ranged between 1.1 and 4.6 ppm Al, 0.5 and 0.8 ppm Fe and 0.4 and 1 ppm Mn, respectively.

Assessing multielement adsorption of trace metals on materials having potential to be used as soil amendments is an essential stage for the remediation success, as soil contamination rarely occurs with a single element. This study evaluated mono-/multielement adsorption of Zn, Cu, Cd, and Pb on aluminum (AMB) and iron mining by-products (IMB, used for comparison). Prior to adsorption, these products were characterized by X-ray diffraction, isoelectric point, infrared spectroscopy, scanning electron microscopy, and microwave furnace digestion. Sorption experiments comprised: (1) pH adjustment (5.5, 6.5, and natural suspension pH), (2) mono- and multielement adsorption, and (3) desorption. Rising pH from 5.5 to natural suspension values (9.5) increased monoelement adsorption of Zn, Cu, Cd, and Pb on AMB up to 3.8-, 1.4-, 6.2-, and 1.1-fold, whereas multielement adsorption was increased up to 17.3-, 2.0-, 20.3-, and 1.2-fold, respectively. Zinc and Cd were less adsorbed than Cu and Pb and more affected by competition. Multielement adsorption at 5.5 pH in AMB resulted in smaller adsorption of Zn (up to 4.6-fold), Cu (1.4-fold), Cd (3.3-fold), and Pb (1.1-fold) when compared with monoelement adsorption. The lower the pH, the smaller the adsorption and the higher the desorption. The AMB showed higher capacity to maintain the elements adsorbed than the IMB.

The environmental impacts of 16 different contaminants originating from the E18 Highway (17,510 annual average daily traffic) were studied over the initial months of the highway’s operational life. Investigative methods used included electrical resistivity surveying, water chemistry analyses, soil analyses, distribution modeling, and transportation modeling of contaminants. The study conclusively showed a year-round infiltration due to melting of the snowpack from road salt, and a strong preferential, anthropogenic pathway due to increased hydraulic conductivities of road construction materials relative to in situ soils. The resistivity surveys produced values well below the expected values for the highway materials, indicating increased ionic content within the unsaturated zone. Time lapse resistivity modeling showed a clear downwards spreading of contamination from the roadway to subsurface distances greater than 5 m. Elevated concentrations of nearly every studied contaminant relative to baseline values were observed, with many metal concentrations within the snow pack averaging values in excess of the Swedish Environmental Protection Agency’s groundwater limitations. Distribution modeling demonstrated a potential offset of peak values from the road surface due to plowing and splash transport processes, and indicated different distribution behavior during winter months than during summer months. One-dimensional transport modeling demonstrated the importance of adsorption and other retentive factors to the migration of contaminants to groundwater and provided an estimate for potential long-term contaminant concentrations.

The complete mineralization of the conazole fungicide triadimefon in water at pH 3 using electrochemical advanced oxidation processes, electro-Fenton and photo electro-Fenton, was achieved. The electrochemical system consisted of a one-compartment electrochemical cell of 100 mL provided with a glassy carbon mesh electrode (cathode) and a concentric outer steel mesh as anode. The electrolysis was realized at constant current. The most remarkable features are as follows: (1) photo electro-Fenton process reaches a complete mineralization of triadimefon after 2 h of electrolysis with respect to electro-Fenton method; and (2) 4-chlorophenol, hydroquinone, carboxylic acids, and inorganic ions were detected as intermediates of degradation processes, which end with the complete mineralization of triadimefon to CO₂ + H₂O. (3) A reaction pathway for the oxidation of triadimefon fungicide by hydroxyl radicals that accounts for almost all detected intermediates is proposed.

The capacity of an iron-modified zeolite was evaluated for the removal of two dyes (red 5 and yellow 6) use in foodstuff; the regeneration of the dye-saturated materials was also considered. The zeolitic material (clynoptilolite type) was treated with sodium chloride (Na-Ze) and then with ferric chloride (Fe-Ze). The sorption kinetics and isotherms were evaluated, considering the effect of pH on the sorption processes. Sorption–regeneration cycles using iron-modified zeolitic material were performed. The sorption kinetics showed that the sodium-modified zeolitic material removed neither red 5 nor yellow 6 dyes, while the iron-modified zeolitic material removed both dyes; the equilibrium time was reached in 48 h for yellow 6, and it was almost reached in the same time for red 5, the removal percentage for red 5 was 89.4 % and for yellow 6 was 96.7 %. The experimental data showed best adjustment to the pseudo-first-order model (Lagergren), which is based on a superficial reaction. The sorption capacities obtained by the sorption isotherms were 1.6 and 1.7 mg/g for red 5 and yellow 6, respectively. The experimental data were best adjusted to the Langmuir–Freundlich model which indicates that the sorption takes place on a heterogeneous material. It was also observed that the sorption capacities increase as the pH decreases. The results on the desorption processes showed that the best regenerator agent was Fenton’s reagent; the capacities increased in each sorption–regeneration cycle using this reagent; for the red 5, the sorption percentage was 73.6 % in the first cycle and 96.3 % in the third cycle and for yellow 6, the removal percentage was 66.7 % in the first cycle and 80.5 % in the second.

The present work investigated the ability of inactive brown seaweed, Turbinaria conoides, to biosorb aluminum(III) and cadmium(II) ions in both single and binary systems. Initial experiments were undertaken to determine the influence of pH and biosorption isotherms of each metallic ion. Owing to the presence of carboxylic groups, T. conoides exhibited high uptake capacity towards Al(III) and Cd(II) through ion-exchange mechanism. In the case of Al(III), T. conoides exhibited maximum biosorption at pH 4 with a capacity of 2.37 mmol/g, whereas the highest Cd(II) biosorption occurred at pH 5 with a capacity of 0.96 mmol/g. For both metal ions, T. conoides exhibited fast kinetics. Several models were used to describe isotherm (Langmuir, Freundlich, Redlich-Peterson, and Toth) and kinetic (pseudo-first and pseudo-second order) data. Desorption and reuse of T. conoides biomass in three repeated cycles was successful with 0.1 M HCl as elutant. In binary systems, the presence of Cd(II) severely affected Al(III) uptake by T. conoides. Compared to single-solute systems, Al(III) uptake was reduced to 56% compared to only 27% for Cd(II). Based on the model parameters regressed from the respective monometal systems, multicomponent Langmuir and Freundlich models were used to predict binary (Al + Cd) system of which the multicomponent Freundlich model was able to describe with good accuracy.