Selective adsorption of Pb(II) and Cr(VI) by surfactant-modified and unmodified zeolites is discussed in this paper. The influences of pH, ionic strength, temperature, and adsorption time on Cr(VI) and Pb(II) adsorption are studied, The characteristics of the surface and inner structures of zeolites before and after modification are analyzed through infrared spectroscopy, scanning electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller analysis, and zeta potential measurement. Results show that the characteristics of electric charge on the zeolite surface had changed after modification, which resulted in selective adsorption of Cr(VI) and Pb(II). Moreover, kinetic study reveals that adsorption by the different zeolites coincides with the Langmuir model and pseudo-second-order kinetic equation. The intraparticle diffusion equation proves that the Cr(VI) adsorption is mainly electrostatic, whereas Pb(II) adsorption proceeds via intrapore and electrostatic adsorption on the zeolite surface. This difference in mechanisms endows selectivity of metal ion adsorption by the modified zeolites. This study provides a reference on zeolite modification for use in various applications, such as wastewater treatment.

The growing production of beef has resulted in the increased volume of liquid residues generated during slaughtering and processing, known as slaughterhouse wastewater. In an attempt to reduce the organic content of this wastewater, blood has been separated from the water, generating slaughterhouse wastewater from green line slaughter and processing (SHWW in natura). The objective of this study was to determine the physical, chemical, and toxicological characteristics of SHWW in natura collected from a bovine slaughterhouse and locker. The results obtained from this characterization showed a high concentration of solids, total volatile acids, alkalinity, macro and micro nutrients, and organic matter (BOD₅ ²⁰°C, COD, and DOC). The effluent presented acute toxicity to the test-organisms P. putida, E. coli, and D. similis, and chronic toxicity to the test-organisms C. silvestri, C. dúbia, E. coli, P putida, and P. subcaptata. Based on the ecotoxicological tests, it was concluded that the compounds of the SHWW in natura were more toxic to microcrustaceans and algae than to bacteria.

This study presents a complementary approach for the evaluation of water quality in a river basin by employing active and passive sampling. Thirty-eight hydrophilic organic compounds (HpOCs) (organohalogen herbicides, organophosphorous pesticides, carbamate, triazine, urea, pharmaceuticals, phenols, and industrial chemicals) were studied in grab water samples and in passive samplers POCIS collected along Strymonas River, Northern Greece, at three sampling campaigns during the year 2013. Almost all the target compounds were detected at the periods of high rainfall intensity and/or low flow rate. The most frequently detected compounds were aminocarb, carbaryl, chlorfenviphos, chloropropham, 2,4-D, diflubenzuron, diuron, isoproturon, metolachlor, and salicylic acid. Bisphenol A and nonylphenol were also occasionally detected. The use of POCIS allowed the detection of more micropollutants than active sampling. Low discrepancy between the concentrations obtained from both samplings was observed, at least for compounds with >50 % detection frequency; thus, POCIS could be a valuable tool for the selection and monitoring of the most relevant HpOCs in the river basin. Results showed relatively low risk from the presence of HpOCs; however, the potential risk associated with micropollutants such as carbaryl, dinoseb, diuron, fenthion, isoproturon, metolachlor, nonylphenol, and salicylic acid should not be neglected.

Studied technosols represent a unique system of a 50-year-old environmental burden after dam failure of coal-ash pond. The released ashes rich in arsenic with a thickness of 1–2 m were covered by a 40-cm thick layer of soil. Long-term exposure and selection pressure of elevated concentrations of arsenic (a range of 93–634 μg/g) induced the formation of the specific adapted autochthonous microorganisms. The phylum Proteobacteria was identified as a dominant phylum in the soils and represented only by one class—Gammaproteobacteria with six species. The species of phylum Firmicutes, Bacteroidetes and Actinobacteria were also identified. Thirty-three species of identified autochthonous microscopic fungi belong to 18 genera with the most abundant Mortierella alpina (Zygomycota). The most frequent identified mycobiota belongs to genera Penicillium, Aspergillus, Trichoderma and Alternaria. The isolates of Alternaria triticina, Bionectria ochroleuca, Chrysosporium queenslandicum, Exophiala psychrophila, Metarhizium robertsii, Trichoderma rossicum and Phlebia acerina were identified for the first time in Slovakia. Despite the stimulation of autochthonous community by nutrient medium and augmentation by native species, As leachability was relatively low—on average 5.63 wt.%, 9.23 wt.% and 17.04 wt.% of the total As for inoculated Pseudomonas chlororaphis ZK-1, Pseudomonas putida ZK-5 and Aspergillus niger, respectively. The highest As leachability was achieved through biostimulation of autochthonous microbiota using liquid SAB medium (34.73 wt.% of total As content). Additionally, microbial activity was efficient in the biovolatilization of As from soils (∼70 wt.% of the total As volatilized). It appears that bioremediation using microorganisms represents one of the possible ways of As removal from soils containing coal-combustion ashes with elevated concentrations of As.

Mining activities can cause drastic disturbances in soil properties, which adversely affect the nutrient cycling and soil environment. As a result, many efforts have been made to explore suitable reclamation strategies that can be applied to accelerate ecology restoration. In this study, we reconstructed mine soils with fly ash, gangue, sludge, planted ryegrass, and inoculated arbuscular mycorrhizal fungi (AMF) in Pangzhuang mine of Xuzhou during 2009 to 2015. The soil aggregation process, enzyme activities (i.e., invertase, urease and acid phosphatase activities), soil organic carbon (SOC) as well as other soil nutrients such as nitrogen, phosphorus, and potassium contents of the reconstructed mine soils were monitored during 6-year reclamation. The integrated application of sludge and AMF led to a promising reclamation performance of mining areas, in which soil aggregate stability, enzyme activities, SOC, and ryegrass biomass were effectively enhanced. The micro-aggregates (< 0.25 mm) decreased with the increase of macro-aggregates (> 0.25 mm) during the reclamation, indicating that macro-aggregates were gradually formed from micro-aggregates during the pedogenesis of reconstructed mine soils. The correlation analysis shows that SOC contents in aggregate fraction of 0.25∼0.5 mm were correlated with aggregate distribution and enzyme activities. Enzyme activities, however, were not significantly correlated with aggregate distribution. The outcomes from the present study could enrich our understanding on soil property changes in pedogenesis process of reconstructed mine soils, and meanwhile, the employment of sludge combined with AMF is suggested to be an effective alternative for the mine soil reclamation.

This study provides an analysis of the spatial distribution and trends of NO, NO₂ and O₃ concentrations in Portugal between 1995 and 2010. Furthermore, an estimation model for daily ozone concentrations was developed for an urban and a rural site. NO concentration showed a significant decreasing trend in most urban stations. A decreasing trend in NO₂ is only observed in the stations with less influence from emissions of primary NO₂. Several stations showed a significant upward trend in O₃ as a result of the decrease in the NO/NO₂ ratio. In the northern rural region, ozone showed a strong correlation with wind direction, highlighting the importance of long-range transport. In the urban site, most of the variance is explained by the NO₂/NOX ratio. The results obtained by the ozone estimation model in the urban site fit 2013 observed data. In the rural site, the estimated ozone during extreme events agrees with observed concentration.

This paper investigated the influence of various florfenicol concentrations on the treatment effect of greenhouse turtle breeding wastewater by intermittent aeration dynamic membrane bioreactor (IADMBR). The results showed that when the florfenicol concentration reached 80 and 120 ng L⁻¹, the average removal efficiencies of ammonia nitrogen and chemical oxygen demand (COD) decreased by 32 and 48 %, respectively. Thus, the enhanced removal of florfenicol and its maintenance at a low concentration are prerequisites to ensure excellent effluent quality. Orthogonal experiments showed that the optimized IADMBR process parameters were hydraulic retention time (HRT) = 5 h, sludge retention time (SRT) = 30 days, and C/N = 2.5; using this combination, the florfenicol concentration was reduced to 25.8 ng L⁻¹, and the average removal efficiency was as high as 78.5 %. The large-scale field pilot test showed that the optimized IADMBR process not only ensured standardized discharge of greenhouse turtle breeding wastewater but also effectively reduced antibiotic pollution and was thus worthy of use in practical applications.

Fe₃O₄-CuO@montmorillonite was prepared using coprecipitation method, and its structure was determined by XRD, IR, and transmission electron micrograph (TEM). Montmorillonite in Fe₃O₄-CuO@montmorillonite nanocomposite allowed the silicate layer of montmorillonite to behave as a barrier, which prevented the agglomeration and natural crystallization of Fe₃O₄ and CuO. Furthermore, the chlorine dioxide (ClO₂) oxidative degradation of anthracene-contaminated soil was studied in detail using Fe₃O₄-CuO@montmorillonite as a magnetic heterogeneous catalyst. The operating parameters such as ClO₂ concentration, catalyst dosage, reaction time, and pH were evaluated. Compared with the conventional ClO₂ oxidation process without the catalyst, the ClO₂ catalytic oxidation system could significantly enhance the degradation efficiency. Under the optimal condition (anthracene concentration 89.8 mg/kg, water soil mass ratio 3:1, initial pH 7, ClO₂ concentration 1 mol/kg, catalyst dosage 1 g/kg, reaction time 30 min, and reaction temperature 25 °C), anthracene degradation efficiency achieved 96.2 %. The catalyst could be easily reused by magnetic separation and used at least 8 cycles without obvious loss of activity. The kinetic studies revealed that the ClO₂ catalytic oxidation degradation of anthracene-contaminated soil with Fe₃O₄-CuO@montmorillonite as catalyst followed pseudo-first-order kinetics with respect to ClO₂ concentration. Thus, this study showed potential application of ClO₂ catalytic oxidation process in remediation of organic pollutant-contaminated soil.

Public concerns regarding the use of copper-based algaecide for controlling problematic algae may arise due to the risks it creates to non-target algae. To examine this concern, a series of comparative algal toxicity experiments were conducted to study effects of prokaryotic and eukaryotic algal cell densities on their responses to exposures of copper sulfate and copper-ethanolamine (Cu-EA). Microcystis aeruginosa and Pseudokirchneriella subcapitata were cultured separately in BG 11 medium to three initial cell densities (5 × 10⁴, 5 × 10⁵, and 5 × 10⁶ cells/mL). The 96-h EC₅₀ values of copper sulfate for M. aeruginosa at the three cell densities were 9, 63, and 112 μg Cu/L, respectively; and were 192, 1873, and 4619 μg Cu/L for P. subcapitata. The 96-h EC₅₀ values of Cu-EA were 101 and 2579 μg Cu/L for M. aeruginosa and P. subcapitata at 10⁶ cells/mL. The margin of safety (MOS) for P. subcapitata at 10⁴ cells/mL was 1.3, 0.9, and 0.8 when M. aeruginosa cell density was 10⁴, 10⁵, and 10⁶ cells/mL. This laboratory study suggests that applying copper-based algaecides to control problematic algae at a relatively low cell density would inhibit their growth with minimum impacts on non-target algae; risks to non-target algae would increase with increases of problematic algal cell density.

Tea saponin (TS), a kind of biodegradable surfactant, was chosen to improve the accessible solubilization of pyrene and cadmium (Cd) in co-contaminated soils cultivated Lolium multiflorum. TS obviously improved the accessibility of pyrene and Cd for L. multiflorum to accelerate the process of accumulation and elimination of the pollutants. The chemical forms of Cd was transformed from Fe-Mn oxides and associated to carbonates fractions into exchangeable fractions by adding TS in single Cd and pyrene-Cd contaminated soils. Moreover, the chemical forms of pyrene were transformed from associated fraction into bioaccessible fraction by adding TS in pyrene and pyrene-Cd contaminated soils. In pyrene-Cd contaminated soil, the exchangeable fraction of Cd was hindered in the existence of pyrene, and bioaccessible fraction of pyrene was promoted by the cadmium. Besides, in the process of the pyrene degradation and Cd accumulation, the effect could be improved by the elongation of roots with adding TS, and the microorganism activity was stimulated by TS to accelerate the removal of pollutions. Therefore, Planting L. multiflorum combined with adding TS would be an effective method on the phytoremediation of organics and heavy metals co-contaminated soils.