Many airborne and soil-borne nanoparticles (NPs) can enter plants, which are the primary producers in the food chain; recently, studies on the genotoxic effects of NPs on plants are emerging. In the present study, the phytotoxic and genotoxic effects of ZnO and CuO NPs on buckwheat (Fagopyrum esculentum) seedlings were estimated. The inhibition of root growth and biomass at the tested concentrations of NP suspensions and dissolved free ion suspensions were compared. Changes in root morphological features and localization of NPs inside the root epidermis cells were observed. Growth of root treated with ZnO NPs (84.9 and 89.6 %) and CuO NPs (75.4 and 80.1 %) at 2,000 and 4,000 mg L -1, respectively, was decreased significantly than control. The root morphological features and NP incorporation into the root epidermal cells at a high dose of NP showed completely different patterns compared to those for the controls. Through random amplified polymorphic DNA assays for comparison of the effect of ZnO and CuO NPs on DNA stability, it was shown as different DNA polymorphisms at 2,000 and 4,000 mg L-1 of ZnO and CuO NPs, compared to those for controls. Our results provide the first clue to the genotoxic effects of ZnO and CuO NPs on early growth of edible plants such as buckwheat. © 2013 Springer Science+Business Media Dordrecht.

Pressure gradients during uniform fluid flow in porous media are traditionally assumed to be linear. Thus, pressure loss across a sample of porous medium is assumed directly proportional to the thickness of the sample. In this study, measurements of pressure gradients inside coarse granular (2-18 mm particle size) porous media during steady gas flow were carried out. The results showed that pressure variation with distance in the porous media was nonlinear near the inlet (where pressure gradients were higher) but became linear at greater distances (with a lower gradient). This indicates that the pressure loss in porous media consists of two components: (1) a linear pressure gradient and (2) an initial pressure loss near the inlet. This initial pressure loss is also known from hydraulics in tubes as a minor loss and is associated with abrupt changes in the flow field such as narrowings and bends. The results further indicated that the minor loss depends on the particle size and particle size distribution in a manner similar to that of the linear pressure gradient. There is, thus, a close relation between these two components. In porous media, the minor loss is not instantaneous at the inlet point but happens over some distance starting upstream from the inlet and ending some distance downstream. © 2013 Springer Science+Business Media Dordrecht.

Large quantities of pollutants such as phthalocyanine which are difficult to degrade by conventional techniques are discharged by the textile industry. Advanced oxidation processes have been shown to be capable of degrading organic compounds and removing colour from the industrial wastewater. In this research, the hydrogen peroxide (H2O2)/UV process under different operative variables has been checked using a photoreactor lab plant to analyse its behaviour in the removal of colour and chemical oxygen demand of synthetic textile wastewater with a pigment named phthalo blue 36:3 (C.I. PB15:3). Different pH and H2O2 concentrations were tested to find the better conditions for the UV/H2O2 process suitable for this kind of pollution; this was carried out as an initial study of the operative variables for the scale-up of this technology. The research has shown that with pH 7 and 5 g/L of H2O2, this process can get an organic matter removal higher than 89 % and a colour removal near 70 %. Different kinetic models of organic matter removal have been checked to analyse and predict the influence of time on the process to model similar conditions of pollution. The high correlation between empirical and theoretical data model was pseudofirst order (R 2 = 0.989 ± 0.007). © 2013 Springer Science+Business Media Dordrecht.

The present work tested effects of a revegetation pattern conducted using Paulownia fortunei (Seem.) Hemsl. (Scrophulariaceae) on soil chemical properties and actinomycete community structure identified by terminal restriction fragment length polymorphism (T-RFLP) technology of 16S rDNA. The results indicated that P. fortunei planting with time effectively improved organic carbon and total nitrogen contents, as well as pH in heavy metal-contaminated soils and, at the same time, enhanced the retention of heavy metals such as Pb, Zn, Cu and Cd in soils. T-RFLP profiles of soil actinomycete communities digested from two restriction enzymes (HhaI and RsaI) showed different specific TRF patterns across four sites with different revegetation time. Nonetheless, number and diversity of terminal restriction fragments for soil actinomycete community increased gradually with P. fortunei planting time and followed consistent patterns with soil organic carbon, total nitrogen, pH and heavy metal contents. Our results revealed a great potential of P. fortunei to remediate heavy metal-contaminated soils.

Electrokinetic extraction, which is an emerging technology, can be used for in situ removal of contaminants by the application of a direct current (DC) electric field across the contaminated subsurface soil. In this study, a kaolinite spiked with Pb (720 mg kg-1) was used to investigate the removal of Pb through electrokinetic extraction in the presence or absence of a cation selective membrane (CSM). The contaminated kaolinite was subjected to a constant DC voltage (2 V cm-1) for 4 days. A low DC voltage applied in absence of CSM developed a high pH interface within the electrokinetic cell. The mobility of Pb thus decreased due to the remarkable rise in the pH values. The inclusion of a CSM improved the removal efficiency but could not achieve the critical surface pH (<pH 3.5). The removal efficiency increased in the presence of Ca(NO3)2, such that 95 % of the spiked Pb was extracted from kaolinite, with 88 % of the Pb being recovered from the cathode chambers. In contrast, only 24 % of the spiked Pb was removed in the presence of ethylenediaminetetraacetic acid (EDTA). Moreover, Pb was detected in the anode chamber solution and 60 % of the spiked Pb accumulated at the anode. In the presence of both EDTA and Ca(NO3)2, Pb migrated and accumulated at the anode, thus indicating that Ca has a negligible effect in the presence of EDTA. © 2013 Springer Science+Business Media Dordrecht.

Agroindustrial by-products and residues from treatment of sewage sludge have been recently recycled as soil amendments. This study was aimed at assessing toxic potential of biosolid, obtained from a sewage treatment plant (STP), vinasse, a by-product of the sugar cane industry, and a combination of both residues using Allium cepa assay. Bioprocessing of these samples by a terrestrial invertebrate (diplopod Rhinocricus padbergi) was also examined. Bioassay assembly followed standards of the Brazilian legislation for disposal of these residues. After adding residues, 20 diplopods were placed in each terrarium, where they remained for 30 days. Chemical analysis and the A. cepa assay were conducted before and after bioprocessing by diplopods. At the end of the bioassay, there was a decrease in arsenic and mercury. For the remaining metals, accumulation and/or bioavailability varied in all samples but suggested bioprocessing by animals. The A. cepa test revealed genotoxic effects characterized by different chromosome aberrations. Micronuclei and chromosome breaks on meristematic cells and F₁ cells with micronuclei were examined to assess mutagenicity of samples. After 30 days, the genotoxic effects were significantly reduced in the soil + biosolid and soil + biosolid + vinasse groups as well as the mutagenic effects in the soil + biosolid + vinasse group. Similar to vermicomposting, bioprocessing of residues by diplopods can be a feasible alternative and used prior to application in crops to improve degraded soils and/or city dumps. Based on our findings, further studies are needed to adequately dispose of these residues in the environment.

A study was carried out under in vitro conditions to characterize the growth of blue green alga, Spirulina platensis, in standard CFTRI medium containing different nanoparticles of copper oxide (CuO) (50 nm, 10 ppm), zinc oxide (ZnO) (50 nm, 10 ppm), tricalcium phosphate (TCP) (<100 nm, 90 ppm), and hydroxy apatite (HA) (<200 nm, 90 ppm). S. platensis exhibited significant higher growth in standard CFTRI medium containing 90 ppm phosphorus as nanoparticles of TCP and HA. On the other hand, calcium phosphate nanoparticles caused significant reduction in nitrate reductase activity as well as in protein content of the alga. Marked change in chlorophyll-a/b ratio was also noted when phosphorus was supplied through nano tricalcium phosphate and nano hydroxy apatite particles as compared to ionic form (K2HPO 4). The study revealed that the growth of Spirulina in the presence of ZnO nanoparticles was retarded, while no growth was observed with CuO nanoparticles. It was concluded that alga Spirulina showed much sensitivity to nanoparticles of zinc and copper (<50 nm) and was able to tolerate the toxicity of nanophosphate (tricalcium phosphate <100 nm; hydroxy apatite <200 nm). © 2013 Springer Science+Business Media Dordrecht.

Diesel exhaust particulate matter contains many semivolatile organic compounds (SVOCs) of environmental and health significance. This study investigates the composition, emission rates, and measurement integrity of 25 SVOCs, including polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and diesel biomarkers hopanes and steranes. Diesel engine particulate matter (PM), generated using an engine test bench, three engine conditions, and ultralow sulfur diesel (ULSD), was collected on borosilicate glass fiber filters. Under high engine load, the PM emission rate was 0.102 g/kWh, and emission rates of ΣPAHs (10 compounds), ΣNPAHs (6 compounds), Σhopanes (2 compounds), and Σsteranes (2 compounds) were 2.52, 0.351, 0.02-2 and 1 μg/kWh, respectively. Storage losses were evaluated for three cases: conditioning filters in clean air at 25 C and 33 % relative humidity (RH) for 24 h, storing filter samples (without extraction) wrapped in aluminum foil at 4 C for up to 1 month, and storing filter extracts in glass vials capped with Teflon crimp seals at 4 C for up to 6 months. After conditioning filters for 24 h, 30 % of the more volatile PAHs were lost, but lower volatility NPAHs, hopanes and steranes showed negligible changes. Storing wrapped filters and extracts at 4 C for up to 1 month did not lead to significant losses, but storing extracts for 5 months led to significant losses of PAHs and NPAHs; hopanes and steranes demonstrated greater integrity. These results suggest that even relatively brief filter conditioning periods, needed for gravimetric measurements of PM mass, and extended storage of filter extracts, can lead to underestimates of SVOC concentrations. Thus, SVOC sampling and analysis protocols should utilize stringent criteria and performance checks to identify and limit possible biases occurring during filter and extract processing. © 2013 Springer Science+Business Media Dordrecht.

The removal and sorption of oil from saline solutions by leaves (L) and roots (R) of Pistia stratiotes are described for the first time. The effects of biomass dose (0.5 and 1.0 g), contact time (30, 60, 90, and 120 min), and initial oil concentration (IOC = 979 ± 9.82, 1,968 ± 8.01, 3,935 ± 40.09, 7,778 ± 196.42, and 15,694 ± 196.41 mg L⁻¹) on removal and sorption (q) were evaluated. Studies included a physicochemical characterization of the biomass. High oil removal (L = 93.71 ± 0.18 % and R = 80.93 ± 0.11 %) and sorption values (L = 2,904.47 ± 4.49 mg g⁻¹ and R = 2,324.38 ± 29.29 mg g⁻¹) were found. Such a high sorption might be related to factors such as a high surface area (128.38 ± 0.61 and 112.62 ± 5.17 m² g⁻¹, for leaves and roots, respectively), a high degree of relative hydrophobicity in the case of the leaves (71.05 ± 0.71 %), and capillary action. A high correlation was found between IOC and sorption, suggesting that the biomass could adsorb oil at IOCs higher than 15,694 ± 196.41 mg L⁻¹. The Freundlich isotherm model was found to best describe crude oil sorption by leaves and roots of P. stratiotes. These sorbent materials could be good candidates to be used during an oil spill.

Measurements of solute dispersion in porous media is generally much more time consuming than gas dispersion measurements performed under equivalent conditions. Significant time savings may therefore, be achieved if solute dispersion coefficients can be estimated based on measured gas dispersion data. This paper evaluates the possibility for estimating solute dispersion based on gas dispersion measurements. Breakthrough measurements were carried out at different fluid velocities (covering the same range in Reynolds number), using O₂ and NaCl as gas and solute tracers, respectively. Three different, granular porous materials were used: (1) crushed granite (very angular particles), (2) gravel (particles of intermediate roundness) and (3) Leca® (almost spherical particles). For each material, 21 different particle size fractions were used. Gas and solute dispersion coefficients were determined by fitting the advection–dispersion equation to the measured breakthrough curves and in turn used to calculate gas and solute dispersivities as a function of mean particle size (D ₘ) and particle size range (R) for the 63 particle size fractions considered. The results show that solute and gas dispersivities are related and that their ratio depends on both R and D ₘ. Based on these observations a simple model for predicting the dispersivity ratio from D ₘ and R, was proposed.