This comprehensive field survey on indigenous European chub (Squalius cephalus L.) presents, for the first time, site-specific variability of trace metal concentrations in the gut content, gastrointestinal tissue and two gastrointestinal sub-cellular fractions, operationally defined as metal-sensitive fraction (S50, which was isolated at 50,000 × g and contains total water soluble proteins), and metal detoxified fraction (heat-treated S50 (HT S50), which contains heat-stable proteins like metallothioneins). At five sampling sites along the Sava River in Croatia 1 to 5-year-old chub were collected in the post-spawning period (September) in order to estimate if metal concentrations in fish intestine are related to their levels in the gut content or fish age. Concentrations of essential metals (Zn, Fe, Cu, Mn) and non-essential Cd decrease in the gut content as follows: Fe > Mn > Zn > Cu > Cd, while in the gastrointestinal tissue: Zn > Fe > Cu ≥ Mn > Cd. Observed difference in metal abundance between the gut content and gastrointestinal tissue points to the selective metal absorption in fish intestine. Relationship among metal concentrations in the gastrointestinal tissue and two sub-cellular fractions (S50/HT S50) is significant for all analysed metals, with Spearman correlation coefficients (r) at p < 0.01 for Zn 0.84/0.73, Cu 0.73/0.73, Fe 0.62/0.58, Mn 0.81/0.78, Cd 0.81/0.82. Site-specific differences point to the age-related increase of gastrointestinal Cu, Mn and Cd towards the downstream sites, while significant correlation between metal concentrations in the gut content and fish age exists only for Mn. In the sub-cellular gastrointestinal fractions, site-specific differences were not recorded on total water-soluble protein and metallothionein concentrations, which might be ascribed to the constitutional level.

Thirty strains of fungi collected from nature were investigated for their ability to grow on agar medium contaminated with Remazol Brilliant Blue R (RBBR) and 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT). The results showed that strain U97, later identified as Trametes versicolor, was the most active decomposer. This fungus decolorized 85 % of RBBR in 6 h and degraded 71 % of DDT in 30 days. In RBBR decolorization, high-performance liquid chromatography analysis revealed that two peaks were identified as metabolic products. Among inducers for ligninolytic enzymes, only veratryl alcohol improved RBBR decolorization and DDT degradation by 93 % and 77 %, respectively. A partial least squares method using Minitab 15 showed that lignin peroxidase exhibited a positive correlation to the abilities of T. versicolor U97 to decolorize RBBR and degrade DDT. A multivariate linear equation, with the same values of ligninolytic activity during RBBR decolorization and DDT degradation, revealed that 1 % RBBR decolorization represented 1.16 % DDT degradation. Screening with agar or liquid medium and improvement of the mathematical modeling could have practical importance in the exploitation of T. versicolor U97 for the removal of DDT on a commercial scale.

The polysaccharidic moieties of three biosorbents (Douglas fir and argan tree barks and argan endocarp) were selectively oxidized, and the subsequent modified materials were tested for their ability to bind Pb(II) or Cd(II) from aqueous solutions. Chemical modifications consisted in two selective oxidations, alone or in combination, of the following groups: primary alcohols with NaOBr catalyzed by (2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl, and vicinal diols with periodate/chlorite. The sodium chlorite oxidation step induced biosorbent degradation that led to a significant decrease of mass yield. Modified materials, characterized by FT-IR spectroscopy and measurement of surface acidity, were investigated for their adsorption capabilities of Cd(II) and Pb(II). Results were compared to the capabilities of crude materials using the Langmuir adsorption model in terms of affinity (b) and maximum binding capacity (q ₘₐₓ). Ion exchange properties were found better for lead than for cadmium before and after chemical modifications. Compared to crude barks, the best results were obtained for Douglas fir barks whose oxidation resulted in significant enhancements of q ₘₐₓ up to × 10 in the case of lead.

Historical profiles of trace element concentrations were reconstructed from two mangrove sediment cores collected within the Ba Lat Estuary (BLE), Red River, Vietnam. Chronologies of sediment cores were determined by the 210Pb method, which showed that each respective sediment core from the south and north entrances of BLE provided a record of sediment accumulation spanning approximately 100 and 60 years. The profiles of Pb, Zn, Cu, Cr, V, Co, Sb, and Sn concentrations markedly increased from the years of the 1920s–1950s, and leveled out from 1950s–1980s, and then gradually decreased from 1980s to present. The profiles of Cd and Ag concentrations increased from 1920s–1940s, and then decreased from 1940s to present. The profile of Mo concentrations progressively increased from 1920s–1980s, then decreased to present. The Mn concentrations failed to show a clear trend in both sediment cores. Results from contamination factors, Pearson’s correlation, and hierarchical cluster analysis suggest that the trace elements were likely attributed to discharge of untreated effluents from industry, domestic sewage, as well as non-point sources. Pollution Load Index (PLI) revealed levels higher than other mangrove sediment studies, and the long-term variations in PLI matched significant socioeconomic shifts and population growth in Vietnam. Geoaccumulation Index showed that mangrove sediments were moderately polluted by Pb and Ag, and from unpolluted to moderately polluted by Zn, Cu, and Sb. The concentrations of Pb, Zn, Cu, Cr, and Cd exceeded the threshold effect levels and effect range low concentrations of sediment quality guidelines, implying that the sediments may be occasionally associated with adverse biological effects to benthic organisms.

Compositions of the xylem fluid of arsenic (As)-stressed hydroponic barley (Hordeum vulgare L. cv. Minorimugi) were investigated. The seedlings were treated with 0, 6.7, 33.5, and 67 μM As in the form of arsenite. The xylem fluids were collected from the cut surface of plants 14 days after treatments and analyzed. Arsenic toxicity reduced the flow rate of xylem fluid. Mineral concentrations of the xylem fluid were measured with particle-induced X-ray emission system, but organic solutes were measured with high-performance liquid chromatography. Arsenic did not influence the concentrations of phosphorus (P), potassium (K), magnesium (Mg), and iron (Fe) very much. However, the concentrations of manganese (Mn), zinc (Zn), and copper (Cu) increased resulting in fairly stable translocation of the elements. The concentration and translocation of Ca decreased in the xylem fluid with increasing As concentrations in the medium. Arsenic concentration increased with increasing As in the nutrient solution, but its translocation decreased. Arsenic treatments did not affect phytosiderophore concentration very much, but their translocation decreased. The concentration of citrate increased but that of malate and succinate decreased in 33.5 μM As-treated plants.

To understand spatial and temporal variations of nitrous oxide (N₂O) fluxes, we chose to measure N₂O emissions from three plant stands (Kobresia tibetica, Carex muliensis, and Eleocharis valleculosa stands) in an open fen on the northeastern Qinghai–Tibetan plateau during the growing seasons from 2005 to 2007. The overall mean N₂O emission rate was about 0.018 ± 0.056 mg N m⁻² h⁻¹ during the growing seasons from 2005 to 2007, with highly spatiotemporal variations. The hummock (K. tibetica stand) emitted N₂O at the highest rate about 0.025 ± 0.051 mg N m⁻² h⁻¹, followed by the hollow stands: the E. valleculosa stand about 0.012 ± 0.046 mg N m⁻² h⁻¹ and the C. muliensis stand about 0.017 ± 0.068 mg N m⁻² h⁻¹. Within each stand, we also noted significant variations of N₂O emission. We also observed the significant seasonal and inter-annual variation of N₂O fluxes during the study period. The highest N₂O emission rate was all recorded in July or August in each year from 2005 to 2007. Compared with the mean value of 2005, we found the drought of 2006 significantly increased N₂O emissions by 104 times in the E. valleculosa stand, 45 times in K. tibetica stand, and 18 times in the C. muliensis stand. Though there was no significant relation between standing water depths and N₂O emissions, we still considered it related to the spatiotemporal dynamics of soil water regime under climate change.

The present work focused on treatment of eosin (EO) by photocatalysis (PC) combined with electrocatalysis (EC) process. Bismuth oxychloride/titanium dioxide (BiOCl/TiO₂) hybrid particles, which were used as new heterogeneous photocatalysts, were exploited in a reverse microemulsion approach and were characterized by XRD, UV–Vis diffuse spectra, BET, and SEM technologies. All degradation experiments were performed using a self-assemble experimental setup, in which PC and EC could be carried out simultaneously or individually. The results indicated that BiOCl/TiO₂ showed enhanced photocatalytic performance under UV irradiation, and 50% BiOCl/TiO₂ exhibited the best photoactivity due to its high degree of crystallization, the mesoporous structure and corresponding large special surface area, improved absorption ability in UV region, and the heterojunction formed between two coupling particles. The combined degradation process displayed synergistic effect on the degradation of EO owing to the generation of H₂O₂ at graphite cathode. The parameters such as, pH, reaction current, and initial concentration of EO were monitored in order to optimize the operating conditions. Pseudo-first-order kinetics was proposed and roughly fitted the combined degradation of EO. The combined system in this work suggested a new research idea for the degradation of dye wastewater.

Temporal depositional rates are important in order to understand the production and occurrence of perchlorate (ClO 4 − ) as limited information exists regarding the impact of anthropogenic production or atmospheric pollution on ClO 4 − deposition. Perchlorate concentrations in discrete ice core samples from the Eclipse Icefield (Yukon Territory, Canada) and Upper Fremont Glacier (Wyoming, USA) were analyzed using ion chromatography tandem mass spectrometry to evaluate temporal changes in the deposition of ClO4 − in North America. The ice core samples cover a time period from 1726 to 1993 and 1970 to 2002 for the Upper Fremont Glacier (UFG) and Eclipse ice cores, respectively. The average ClO4 − concentration in the Eclipse ice core for the time period from 1970 to 1973 was 0.6 ± 0.3 ng L−1, with higher values of 2.3 ± 1.7 and 2.2 ± 2.0 ng L−1 for the periods 1982–1986 and 1999–2002, respectively. All pre-1980 ice core samples from the UFG had ClO4 − concentrations <0.2 ng L−1, and the post-1980 samples ranged from <0.2 ng L−1 to a maximum of 2.6 ng L−1 for the year 1992. A significant positive correlation (R = 0.75, N = 15, p < 0.001) of ClO 4 − with SO 4 2− was found for the annual UFG ice core layers and of ClO4 − with SO 4 2− and NO 3 − in sub-annual Eclipse ice samples (R > 0.3, N = 121, p < 0.002). The estimated yearly ClO 4 − depositional flux for the Eclipse ice core ranged from 0.6 (1970) to 4.7 μg m−2 year−1 (1982) and the UFG from <0.1 (pre-1980) to 1.4 μg m−2 year−1 (1992). There was no consistent seasonal variation in the ClO 4 − depositional flux for the Eclipse ice core, in contrast to a previous study on the Arctic region. The presence of ClO 4 − in these ice cores might correspond to an intermittent source such as volcanic eruptions and/or any anthropogenic forcing that may directly or indirectly aid in atmospheric ClO 4 − formation.

Anionic surfactants, the earliest and the most common surfactants in detergent and cosmetic product formulations contribute significantly to the pollution profile of the ecosystem. Linear alkylbenzene sulfonates (LAS), a major chemical constituent of detergents, forms an imperative group of anionic surfactants. Bioremediation of LAS by conventional processes such as activated sludge is ineffective due to the low kinetics of degradation by unsuitable organisms and foam production. Hence this study was focused on isolating and characterizing indigenous LAS-degrading bacteria from soil. Twenty different LAS-degrading bacteria were isolated from detergent-contaminated soil by enrichment culture technique and degradation efficiency was assessed by Methylene Blue Active Substances (MBAS) assay and by reverse-phase high-performance liquid chromatography (HPLC) analysis. The most efficient LAS-degrading isolates, L9 (81.33 ± 0.7) and L12 (81.81 ± 0.8), were selected and identified as Pseudomonas nitroreducens (MTCC 10463) and Pseudomonas aeruginosa (MTCC 10462). The 16S rDNA sequences of the isolates were deposited in NCBI GenBank under the accession numbers HQ 271083 (L9) and HQ 271084 (L12). The isolates were capable of degrading 0.05 g/l LAS at 25 °C and pH 7.0–7.5. Presence of a solid support caused biofilm formation which in turn enhanced LAS degradation. The isolates tend to display diauxic growth with alternate carbon source such as dextrose. These isolates also have the capability to degrade other xenobiotics like hydrocarbons and pesticides. Since xenobiotic pollutants in nature occur as a mixture of compounds rather than single pollutants, the potential of these two indigenous LAS-degrading isolates to degrade multiple xenobiotics gains relevance.

Arthrobacter sp. Sphe3 and Bacillus sphaericus cells were used for Cu(II) biosorption. The effect of contact time, biosorbent dose, equilibrium pH, temperature and the presence of other ions on the efficiency of the process were extensively studied. Optimum pH value and biomass concentration were determined at 5.0 and 1.0 g/l, whereas contact time was found to be 5 and 10 min for Arthrobacter sp. Sphe3 and Bacillus sphaericus biomass, respectively. Equilibrium data fitted very well to Freundlich model (R ²â€‰= 0.996, n = 2.325, K f = 8.141) using Arthrobacter sp. Sphe3. In the case of B. sphaericus, a Langmuir adsorption model [R ²â€‰= 0.996, Q ₘₐₓ = 51.54 mg-Cu(II)/g] showed to better describe the results. Potentiometric titration and Fourier transform infrared (FTIR) spectroscopy showed that amine, carboxyl and phosphate groups participate in Cu(II)-binding. The calculated thermodynamic parameters indicated the spontaneous and feasible nature of Cu(II) biosorption on both biosorbents. Selectivity of Cu(II) biosorption was examined in binary and multi-ions systems with various anions and cations which are commonly found in municipal and industrial wastewater. A specificity towards Cu(II) was observed in binary mixtures with Cl⁻, CO ₃ ⁻² , NO ₃ ⁻ , SO ₄ ⁻² , PO ₄ ⁻³ , Mg+² and Ca+², and As(V) with the maximum uptake capacity remaining constant even at high competitive ion’s concentrations of 200 mg/l. Desorption studies showed that Cu(II) could be completely desorbed from Cu(II)-loaded Arthrobacter strain Sphe3 and B. sphaericus biomass using 1.0 and 0.8 M HCl, respectively, and both bacterial species could be effectively reused up to five cycles, making their application in wastewater detoxification more attractive.