Decolorization of six synthetic dyes and two raw textile effluents (A and B) by eight basidiomycetous fungi was investigated. Among eight basidiomycetous fungi, fungal isolate RCK-1 decolorized textile effluent A maximally (42%), while fungal isolate RCK-3 was found to decolorize more of Congo Red (69%), Xylidine Ponceau 2R (100%), Poly R-478 (96%), Indigo Carmine (99%), Lissamine Green B (90%), Toluidine Blue (57%) and textile effluent B (54%), than the rest of fungi. Percentage decolorization of all synthetic dyes and textile effluents by the new fungal isolates RCK-1 and RCK-3 was higher compared to the most widely studied simultaneous lignin degrader, Phanerochaete chrysosporium and selective lignin degrader, Pycnoporus cinnabarinus, when tested in liquid cultures. A statistically significant positive correlation between laccase production and decolorization of dyes and effluents was obtained as compared to other ligninolytic enzymes (lignin peroxidase and manganese peroxidase) production. This showed the importance of the differential contribution of the different ligninolytic enzymes towards the decolorization of the synthetic dyes and textile effluents. The substantially higher ligninolytic enzyme production by the fungal isolates RCK-1 and RCK-3 also suggested their potential use for textile effluent treatment and other possible biotechnological applications.

The potential competitive effect of background electrolytes (Na₂HPO₄ ·2H₂O, NaHCO₃, Na₂SO₄ and NaCl solutions) on arsenate adsorption onto synthetic 2-line ferrihydrite has been studied by means of kinetic batch experiments conducted at pH values from 4.0 to 10.0 and at anionic concentrations of 0.01 and 0.1 M. The results indicate that the adsorptive capacity of ferrihydrite for arsenate decreases strongly in the presence of phosphate species at pH in the range of 4-10 and in the presence of bicarbonate at pH 8.3 as a consequence of their competitive effect. Analogously to phosphate, a surface interaction of inner-sphere type between ferrihydrite and bicarbonate is suggested. Chloride has negligible effects on arsenate adsorption processes, confirming it as an outer-sphere ion that does not compete with the inner-sphere binding peculiar to arsenate onto ferrihydrite. Sulphate exhibits an intermediate behaviour; at 0.01 M concentration, the competitive effect of sulphate is similar to that of chloride, whereas at 0.1 M concentration sulphate shows a moderate influence on arsenate adsorption. The results of the kinetic studies can be summarised by the following order of competitive capacity: phosphate > carbonate > sulphate > chloride. The process of arsenate adsorption follows pseudo-second order kinetics and the reaction half-time notably increases in the presence of strong competitor anions such as phosphate and carbonate with respect to an ineffective competitor anion such as chloride. Modelling of arsenate adsorption with PHREEQC, according to the Generalized Two-Layer Model, confirms that the pH effect is notably less important than the competitive effect of carbonate species in determining the amount of arsenate adsorbed onto ferrihydrite at pH 8.3 in 0.1 M NaHCO₃ solution, whereas the model greatly underestimates the competitive effect of carbonate species at pH 8.3 in 0.01 M NaHCO₃ solution. The results of the batch experiments in 0.1 M NaHCO₃ solution are substantiated by XPS analyses of ferrihydrite after immersion in the same solution, both with and without dissolved arsenate. XPS confirms the interaction between ferrihydrite surface and arsenate; the binding energy of As3d shifts towards higher binding energies after adsorption with respect to the pure compound Na₂HAsO₄·7H₂O taken as reference standard. In presence of carbonate species, the As3d binding energy is found at intermediate values. XPS quantitative analysis shows a depletion of arsenate on ferrihydrite surface, providing further evidence of the competition of the two species (i.e. arsenate and bicarbonate) for the ferrihydrite adsorption sites. Important environmental implications concerning arsenic mobility, as well as possible application in various fields (e.g. irrigation agriculture, soil decontamination, water treatment), might derive from these findings.

Two varieties of Bechmeria nivea (L.) Gaud. (Ramie), namely, triploid Tri-2 and diploid Xiangzhu-3, were potted with soils from Guangdong for 15 weeks and treated with 10 mmol kg⁻¹ EDTA or EGTA before harvest at 17th week. Lead, Zn, and Cd in plant and soil materials were analyzed, and their potential ecological risk in soils was simultaneously evaluated. These three metals in soils was found to be above 14.4, 3.0, and 29.9 times higher than the national (China) background value, 10.9, 6.19, and 96.7 times higher than the local (Guangdong) background value, and 1.25, 1.20, and 9.67 times higher than the maximum permissible concentration for soils, respectively. An ecological risk analysis of metals using Häkanson's method indicated an extremely high contamination and a significantly high potential ecological risk by these three metals in soils. The both ramie varieties contained respective concentration exceeding the concentration of <10, <80, and <0.27 mg kg⁻¹, respectively, for Pb, Zn, and Cd in normal plants, suggesting they were multimetal tolerant. Tri-2 generally contained higher Pb, Zn, and Cd than Xiangzhu-3. Treatment with EDTA or EGTA applied at 10 mmol kg⁻¹ generally promoted Pb or Cd concentration in both plants while the uptake of Zn was depressed. The ramie variety of Tri-2 and Xiangzhu-3 could extract 0.161 and 0.147 t ha⁻¹ of Cd, respectively, equaling to the 0.17 t Cd per hectare by Cd-hyperaccumulating species Viola baoshanensis. Therefore, two ramie varieties in this study had a higher extracting potential for removal of Cd from contaminated soils.

Immobilizing materials such as lherzolite could reduce metal bioavailability but the effectiveness of lherzolite on the extractability and bioavailability of cadmium (Cd) and zinc (Zn) is rarely investigated. We conducted a greenhouse experiment to investigate the effect of 5% application of lherzolite to a contaminated soil on the chemical fractionation of Cd and Zn and their uptake by radish (Raphanus sativus L.) and Japanese mustard spinach (Brassica rapa L. var. perviridis). Both plants were grown in a highly contaminated (with Cd and Zn) sandy loam soil. Plants were cultivated consecutively three times in the same pots. After the third cultivation, soil samples were collected and analyzed by sequential extraction procedure into five operationally defined fractions (F1—exchangeable, F2—carbonate-bound, F3—oxides-bound, F4—bound with organic matter, and F5—residual). Addition of lherzolite to soil decreased 50% of exchangeable (F1) Cd but it increased the carbonate (F2), oxide (F3), and organic (F4) fraction Cd. For Zn, application of lherzolite resulted into the reduction of both F1 (87%) and F2 (33%) fractions but it increased the F3, F4, and F5 fractions. The reduction in exchangeable fraction of Cd and Zn in the soil resulted in higher plant growth and lower concentrations of both Cd (64% to 92%) and Zn (78% to 99%) in plant tissues of both plant species grown. We may thus conclude that application of lherzolite resulted into lower availability of these metals in the soil leading to lower uptake of Cd and Zn by plant roots, lower toxicity, and ultimately higher plant growth.

We studied nutrient removal by Phragmites australis in the Albujón rambla, the main drainage system that discharges into the Mar Menor, a Mediterranean coastal lagoon of high conservation interest, but highly threatened by point and nonpoint pollution derived from tourism and agricultural activities. We measured aerial biomass and N and P concentrations in both aboveground and belowground tissues of common reed during an annual cycle that included two cutting events and two periods of reed growth (one at the end of summer after cutting and another at the beginning of spring, following their natural cycle). The temporal variation of N and P concentrations was related to the phenology of the plant and cutting events. The maximum nutrient concentrations were recorded in young stems in the initial stages of the autumn growing season (35.86 mg N g⁻¹ and 2.38 mg P g⁻¹). The phosphorus dynamics showed evidence of translocation processes related with growth activity, although no evidence of N translocation was found. In November and in summer, when aerial growth ceases because of the hard conditions, the P concentration in rhizomes was higher than in stems, while in spring and in September, the period of maximal growth, the reverse relation was found. The highest total amounts of the two elements in the aboveground biomass (0.54 Tm N ha⁻¹ and 0.25 Tm P ha⁻¹) were reached in July, coinciding with the highest biomass (3.72 kg DW m⁻²), which then decreased to approximately half in August. Nutrient content in the aboveground tissues was highly dependent on the ammonium and nitrate water concentrations. In addition, the N content was inversely related to the Corg/N of sediments, while the P content was influenced positively by the phosphorous concentration of the water. Common reed of the Albujón rambla corresponds to the assimilation type, adapted to nutrient-rich habitats, which is characterized by a pronounced external N cycle and P internal reserves. Based on the results obtained, we propose a management plan for common reed to help control eutrophication of the Mar Menor lagoon. This would bring forward reed cutting to the beginning of summer, instead of August, coinciding with the time of maximum aerial biomass, greater nutrient retention, and lower risk of strong precipitation.

Background, aim, and scope Diffusive gradients in thin films (DGT) have been recognized as a suitable tool to assess in situ metal bioavailability in soils. Mine tailings have some singular characteristics such as high heavy-metal concentrations, low pH, or absence of water retention capacity that may compromise the correct application of this technique whose applicability is known to be pH dependent. The goal of this study was to determine the response of DGT devices in heavy-metal-polluted mine tailings with different pH. In addition some experiments were performed in order to determine the effect of acidic pH and dissolved ions on the binding properties of the chelating resin. Materials and methods We tested DGT devices on three different mine tailings: acid pH 3, acid tailing limed to pH 5.5, and neutral pH 7.2. The tailings showed high metal concentrations, e.g., 7,000 mg kg⁻¹ Pb, 9,000 mg kg⁻¹ Zn, and 380 mg kg⁻¹ Cu. Diffusive and Chelex resin gels were prepared according to previously published methods. Two chelating resins and diffusive gels thicknesses (0.4 and 0.7 mm) were tested. Four DGT devices of each type were placed during 24 h in pots (one device per pot) containing 1 kg mine tailings in a climate chamber with humidity (50-90%) and controlled temperature conditions (night 16°C and day 23°C). Pots were irrigated with deionized water to field capacity, and then two different experiments were performed: (a) allowing free drainage and (b) maintaining the water saturation. In addition, we tested DGT devices in solutions at pH 3 with similar properties to the soil solution measured in the acid tailing. Eluted Zn, Cd, Pb, and Cu from the chelating resins were measured using inductively coupled plasma-optical emission spectrometer (ICP-OES; Vista-MPX Varian). Results and discussion The metal concentrations taken up by the DGT devices were affected by the different pH values of the tailings. The highest metal concentrations measured with DGT (C DGT) were obtained in the pH 3 treatments (both saturated and free drainage). Significant differences for C DGT were observed between water-saturated and free drainage treatments in the acid pH 3 tailing. When limed pH 5.5 tailing and neutral pH 7 tailing were considered, these differences were lower and not significant. In pH 3 tailings low values for C DGT/C soil solution were obtained (<0.06), indicating that these soils have a low capacity to resupply depleted metals to the solution. The limed acid tailing and the neutral tailing showed values between 0.05 and 0.94 indicating a much more rapid resupply from the solid phase. Deployment under water-saturated conditions yielded much higher C DGT values than under free drainage, indicating the importance to adequately control the moisture content in these soils with poor water retention capacity. In solutions with pH 3 mimicking the soil solution composition of the tailings, a loss of the binding capacity of the resin of 50-60% and 60-80% for Zn in 0.7-mm DGT and 0.4-mm DGT devices, respectively, was observed. As a consequence, 0.7-mm DGT devices had better reliability to carry out in situ determinations in solutions with high metal concentrations and low pH. Conclusions The use of DGT in mining soils can be a promising tool to study bioavailable metals concentrations in mine tailings but it has to be used carefully under acidic pH. Competition with other cations that are present at very high concentrations may hinder the accumulation of metals by the chelating resins, which should be tested under the conditions of the particular mine tailing.

This study was carried out in order to assess both the deposition of heavy metal and nitrogen in a mountain ecosystem with low levels of metal deposition and its possible interactions with factors such as lithology and topography. For this purpose, samples of Hypnum cupressiforme Hedw. and topsoils were collected in a forest catchment within Bertiz Natural Park, an International Cooperative Programme on Integrated Monitoring site. Trace metals levels in mosses can be considered low compared with values reported elsewhere in Europe, and the dust soil mineral particles seemed to be the main source of these values. Only Cd and Hg presented external inputs, probably with an anthropic origin, for mosses according to the enrichment factor values, whereas historical pollution-related deposition in soils was determined for Pb, Cu, and Ni, attending to their total/extractable ratio.

Many natural vegetation species have been shown to be negatively affected by ozone. This study has investigated how the presence of competing species in a community affects two common responses to ozone: visible injury and senescence. Monocultures and mixtures of Trifolium repens and Lolium perenne were grown in large containers and were exposed in solardomes to either a rural episodic ozone profile (AOT40 of 12.86 ppm h) or control conditions (AOT40 of 0.02 ppm h) for 12 weeks. The proportion of ozone-injured or senesced leaves was different in the different regions of the canopy. The highest proportions of injured/senesced leaves were in the plant material growing at the edge of the canopy and the upper canopy, with a significantly lower proportion of injured leaves in the inner canopy. The presence of L. perenne increased the proportion of ozone-injured leaves in T. repens at the final harvest, whilst the presence of T. repens decreased the proportion of senesced leaves in L. perenne. In L. perenne, the proportion of injured leaves at the edge and inner canopy decreased significantly when grown in competition, whilst for T. repens the reverse effect occurred in the inner canopy only. Different mechanisms appeared to influence the interaction between response to ozone and competitors in these two species. In L. perenne the response to ozone may have been related to nitrogen supply, whereas in T. repens canopy structure was more important.

Results of a comprehensive study are presented on the spatial and depth-related distribution of persistent organic pollutants (POPs) in sediments of the Brno reservoir, Czech Republic. Based on sedimentological observations, three major historic phases were identified related to the evolution of the depositional environment, flow rate, and material input. Data on organic carbon, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides showed specific distribution patterns in a 3-m-deep core. The analysis of the depth trends of the geochemical data combined with sedimentology made it possible to distinguish between remote sources of the pollutants, early weathering alterations of POPs, transport by river associated with organic matter as sorbent on one hand, and local sources weakly related to lithology on the other hand. The integrated sedimentological and environmental geochemical archive provided an improved dynamic view of the pollution in historical terms.

The oxidation of di-(2-ethylhexyl) phthalate (DEHP) in solution using UV/H₂O₂ and direct UV photolysis are analyzed in this study. It was found that DEHP was 100% removal in the solution by 180-min UV/H₂O₂ treatment and 73.5% removal by 180-min direct UV photolysis. The effect of different factors, such as DEHP concentration, H₂O₂ concentration, and UV light intensity, on photochemical degradation was investigated. The degradation mechanism of DEHP and the acute toxicity of intermediates were also studied. The photochemical degradation process was found to follow pseudo-first-order kinetics. The results of our study suggested that the concentration with 40 mg/L H₂O₂ and 5 μg/mL DEHP in the solution at pH 7 with 10.0 × 10⁻⁶ Einstein l⁻¹ s⁻¹ UV was the optimal condition for the photochemical degradation of DEHP. The photochemical degradation with UV/H₂O₂ can be an efficient method to remove DEHP in wastewater.