Genotoxicity of 5-fluorouracil (5-FU), etoposide (ET) and cadmium chloride (CdCl₂) was evaluated in Limnodrilus udekemianus, cosmopolitan tubificid species, by alkaline single-cell gel electrophoresis (comet assay). Groups of 50 individuals were exposed in vivo in water-only short-term (96 h) tests to 5-FU (0.004, 0.04, 0.4, 4 and 40 μM), ET (0.004. 0.04, 0.4 and 4 μM) and CdCl₂ (0.004, 0.04, 0.4, 4 and 40 μM). Mortality of worms was observed only for CdCl₂ (4 and 40 μM). Cell viability lower than 70 % was detected for 5-FU (0.4, 4 and 40 μM), ET (4 μM) and CdCl₂ (0.4 and 4 μM). All tested substances induced significant increase of DNA damage except 0.004 μM of ET. L. udekemianus being sensitive to all tested substances indicates that it can be used in ecogenotoxicology studies. Concern should be raised to cytostatics, especially to 5-FU, since concentration of 0.004 μM induced DNA damage is similar to ones detected in wastewaters.

The aboveground tissue of plants is important for providing roots with constant photosynthetic resources. However, the aboveground biomass is usually harvested before winter to maintain the permanent removal of nutrients. In this work, the effects of harvest on plants’ involvement in oxygen input as well as in microbial abundance and activity were investigated in detail. Three series of constructed wetlands with integrated plants (“unharvested”), harvested plants (“harvested”), and fully cleared plants (“cleared”) were set up. Better performance was found in the unharvested units, with the radial oxygen loss (ROL) rates ranging from 0.05 to 0.59 μmol O₂/h/plant, followed by the harvested units that had relatively lower ROL rates (0.01 to 0.52 μmol O₂/h/plant). The cleared units had the lowest removal efficiency, which had no rhizome resources from the plants. The microbial population and activity were highest in the unharvested units, followed by the harvested and cleared units. Results showed that bacterial abundances and enhanced microbial activity were ten times higher on root surfaces compared with sands. These results indicate that late autumn harvesting of the aboveground biomass exhibited negative effects on plant ROL as well as on the microbial population and activity during the following winter.

We need specific and competent adsorbents to remove arsenic and bring it down to permissible levels in drinking water. Therefore, industrial byproducts are extensively applied to produce large amounts of natural adsorbents. Similarly, managing optimum arsenic adsorption with palm oil clinker sand (POCS) is possible through a careful statistical planning of adsorption variables. We plan and perform a minimum number of experiments to (1) obtain optimum arsenic adsorption and (2) provide a new possible application opportunity to the industrial waste managers and future planners. We observed that adsorption of arsenic was dependent on the pH of the system, initial concentration of arsenic (mg L⁻¹), amount (mg) of POCS, and temperature of the bio-adsorption system. A correlation among the study variables was constructed by three-dimensional (3D) response surfaces and two-dimensional (2D) contour plots based on central composite design (CCD) experiments in a batch mode of study. A quadratic model fitted well with the experimental data and better explained the superiority of current bio-adsorption system and efficient removal of arsenic from water samples. We confirmed that the selected variables were experimentally and statistically significant and controlled the overall adsorption response by the batch system. A comparative and thorough analysis of the adsorption process confirmed that selected variables were mutually interacting in a nonlinear fashion in this study. Excellent experimental results and external comparative studies prove the relative importance of the present model and adsorption system for arsenic remediation biotechnology.

SrCO₃ was formed and added as a carrier into copper-based catalyst (CuZnAl catalyst) prepared by hydrothermal method before the catalyst incorporates with HZSM-5. The CuZnAlSr catalyst was characterized by SEM, BET, XRD, IR, and activity-evaluation system in a fixed-bed tubular reactor equipped with chromatograph (GC). The conversion of CO₂ reaches 30.30 %, and the overall yield of methanol and dimethyl ether is 27.80 %. Catalytic property as to CO₂ conversion has only slight decrease even up to 150 h of reaction time. The addition of SrCO₃ enhanced the activity of the catalyst through providing a tridimensional frame and electron transfer bridge.

The present work studies the remediation of a B20 (20 % biodiesel, 80 % diesel) biodiesel blend-contaminated soil (1,000 mg kg⁻¹) with persulfate activated by iron. Three different sources of iron (Fe(II)), granular zerovalent iron (gZVI), and a slurry of nanoparticles of zerovalent iron (nZVI), without pH adjustment were tested. Besides, the effect of the addition of chelating agents, such as trisodium citrate (SC), or citric acid (CiA), has been also studied. SC promotes pH under near-neutral conditions and reaction takes place at low rate at these experimental conditions. On the other hand, the use of CiA leads to an acidic pH and chelating agent is oxidized at higher rate than total petroleum hydrocarbons (TPH). Therefore, CiA addition does not seem to produce any improvement on the removal efficiency of TPH. Regarding the three different sources of iron used as activators, Fe(II), gZVI and nZVI, in absence of chelating agent, under acidic pH and by adding the same amount of iron, the highest TPH conversion was obtained with ZVI (about 60 %), while a conversion of about 40 % was obtained with the addition of Fe(II). The maximum TPH conversion value was achieved in shorter time using nZVI. Concerning the removal efficiency of each fraction of biodiesel abated, fatty acid methyl esters (FAME) were by far the easiest to oxidize, achieving 100 % of conversion, either by using Fe(II) or nZVI activated persulfate.

Biochar has great advantages and potentials on soil amendment and polluted soil remediation. In order to explore these applications, a pot experiment was carried out to research the effect of biochar on the heavy metal speciation in paddy soil and the heavy metal accumulation of paddy rice from Chengdu plain, Sichuan Province. The experimental results show that wine lees-derived biochar can efficiently increase soil pH, decrease the contents of soil exchangeable heavy metals, and promote heavy metal transformation to residual fraction. Moreover, application of biochar can reduce the accumulation of heavy metals in paddy plant, decrease the migration ability of heavy metals to the aboveground part of the plant, and consequently cut down contents of heavy metals in rice. When biochar dosage was 0.5 % in weight, the contents of soil exchangeable Cr, Ni, Cu, Pb, Zn, and Cd decreased 18.8, 29.6, 26.3, 23.0, 23.01, and 48.14 %, respectively, which all significantly differed from CK (P < 0.05), and the contents of heavy metals in plant roots, stems, leaves, rice husk, and rice all decreased accordingly, among which Zn, Cd, and Pb decreased 10.96, 8.89, and 8.33 % respectively. When biochar dosage increased to 1 %, heavy metal contents in roots, stems, leaves, rice husk, and rice decreased further. Therefore, wine lees-derived biochar shows a great potential in remediation of heavy-metal-polluted soil, and this work provides theoretical basis for restoring heavy-metal-polluted soil using biochar.

Chemical methods have been used for the remediation of arsenic (As)-contaminated water; however, ecological consequences of these methods have not been properly addressed. The present study evaluated the effects of the Fe-oxide-coated sand (IOCS) remediation method on As toxicity to freshwater organisms (Lemna disperma, Chlorella sp. CE-35, and Ceriodaphnia cf. dubia). The As removal efficiency by IOCS decreased substantially with time. The IOCS remediation method was less effective at suppressing the toxicity of Asⱽ than Asᴵᴵᴵ to L. disperma but was highly effective in reducing both the Asᴵᴵᴵ and Asⱽ toxicity to C. cf. dubia. The growth of Chlorella sp. was significantly higher (p < 0.05) in remediated and pre-remediated water than in controls (non-As-contaminated filtered Colo River water) for Asᴵᴵᴵ, while the opposite was observed for Asⱽ, indicating that Asⱽ is more toxic than Asᴵᴵᴵ to this microalga. Although the IOCS can efficiently remove As from contaminated water, residual As and other constituents (e.g. Fe, nitrate) in the remediated water had a significant effect on freshwater organisms.

Peatlands serve as important stores of organic matter and regulators of nutrient and metal export to surface waters, yet relatively little is known regarding the impact of more than a century of metal, sulfur, and acid deposition on microbial activity in acidic, nutrient-poor peatlands that are common features around Sudbury, Ontario. In this study, eight peatlands were selected at varying distances from the Copper Cliff Smelter that was once the largest point source of sulfur dioxide and sampled for analysis of nutrient and metal content. Basal microbial respiration, relative response to substrate addition (four synthetic and four natural substrates) assessed as CO₂production rates and microbial biomass were assessed in surface (0–10 cm) peat samples. Bacterial and fungal communities within the peat samples were profiled using terminal restriction fragment length polymorphism analysis. Basal respiration (i.e., carbon mineralization in absence of substrate addition) was lowest and Cu and Ni concentrations and the degree of humification (assessed by the von Post scale) in surface peat samples were highest close to the smelter. Each peatland had a unique bacterial community when assessed using non-metric multidimensional scaling, whereas the fungal community was variable with no consistent patterns across the sites. Despite differences in microbial communities, substrate-induced respiration rates did not differ among peatlands as sites generally responded similarly to carbon substrate additions. Basal respiration rates were related to the humification status of the peat, which was potentially related to environmental degradation in the peatlands or surrounding terrestrial systems closer to the Sudbury smelters.

A multivariate analysis was performed in the city of Florence (Italy) to investigate the influence of road traffic and meteorology on air pollution levels at urban traffic stations. Focussing on main traffic-related pollutants (CO, NO, NO₂, NO ₓ and PM₁₀), two typical urban road configurations were analysed: a street canyon and an open road. In addition to traffic flows, basic meteorological parameters were considered: wind speed, air temperature and relative humidity. The influence of all drivers by period of the year and day of the week was analysed with correlation analysis, while a statistical model was developed to predict concentrations at traffic stations by using predictors as urban background concentrations, traffic flows and a site-specific constant. Trained on a 1-year period (2008), the model was validated over an independent 1-year period (2007). The highest correlation of urban traffic concentrations was found vs. background concentrations, markedly for PM₁₀ (r = 0.85–0.87). The influence of road traffic was the highest for NO₂ (r = 0.51–0.58) and the lowest for PM₁₀ (r = 0.36–0.40). Urban-scale poor advection conditions proved to affect PM₁₀ peak levels more significantly than local traffic increase. For all pollutants, good forecasting capability was achieved by the developed statistical model, generally performing better at the street canyon (r = 0.79–0.86) than at the open road (r = 0.72–0.82).

A pure clay ball and surface-modified clay ball were investigated to remove phosphate from synthetic wastewater; phosphate causes eutrophication in hydro-ecological systems. Adsorption tests of phosphate from aqueous solutions onto two types of adsorbents were conducted. The maximum phosphate adsorption capacities of the pure and surface-modified clay ball were found to be 0.084 and 8.869 mg/g, respectively. In a fixed-bed column packed with surface-modified clay balls, the first breakthrough of phosphate appeared after approximately 4000 min. In addition, the phosphate adsorbed on the surface-modified clay ball was effectively desorbed using a 1 M zirconium sulfate solution, and the adsorbent was regenerated for four adsorption and three desorption cycles by maintaining the adsorption capacity at the value before regeneration. X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX), and Brunauer-Emmett-Teller (BET) analysis method were performed to reveal the characteristics of the surface-modified clay ball. Cytotoxicity experiment was conducted on the developed adsorbents, and as a result, these showed low cytotoxic effect on the human cells. These results indicated that the surface-modified clay ball, due to the low cost, high adsorption capacity, and non-toxicity, has the potential to be utilized in the cost-effective removal of phosphate from aqueous solutions.