Integrated biomonitoring of air quality with plants and lichens: a case study on ambient ozone from central Italy

A biennial integrated survey, based on the use of vascular plants for the bioindication of the effects of tropospheric ozone together with the use of automatic analysers of ozone, as well as the mapping of lichen biodiversity was performed in the area of Castelfiorentino (Tuscany, central Italy). Photochemically produced ozone proved to be a fundamental presence during the warm season, with maximum hourly means reaching 114 ppb, exceeding the information threshold as fixed by EU: the use of supersensitive tobacco Bel-W3 confirmed the opportunity of carrying out detailed cost-effective monitoring surveys. The potential for didactical and educational implications of this methodology are appealing. Critical levels set up for the protection of vegetation have exceeded considerably. The comparison of biomass productivity in sensitive and resistant individuals (NC-S and NC-R white clover clones, in the framework of an European network) provided evidence that ambient ozone levels are associated with relevant reduction (up to 30%) in the performance of sensitive material; effects on flowering were also pronounced. The economic assessment of such an impact deserves attention. Mapping of epiphytic lichen biodiversity – which has been used to monitor air quality worldwide – was not related to ozone geographical distribution as depicted by tobacco response.     

Growth, photosynthetic and respiratory responses to sub-lethal copper concentrations in Scenedesmus incrassatulus (Chlorophyceae)

In the present paper we investigated the effects of sub-lethal concentrations of Cu²⁺ in the growth and metabolism of Scenedesmus incrassatulus. We found that the effect of Cu²⁺ on growth, photosynthetic pigments (chlorophylls and carotenoids) and metabolism do not follow the same pattern. Photosynthesis was more sensitive than respiration. The analysis of chlorophyll a fluorescence transient shows that the effect of sub-lethal Cu²⁺ concentration in vivo, causes a reduction of the active PSII reaction centers and the primary charge separation, decreasing the quantum yield of PSII, the electron transport rate and the photosynthetic O₂ evolution. The order of sensitivity found was: Growth > photosynthetic pigments content = photosynthetic O₂ evolution > photosynthetic electron transport > respiration. The uncoupled relationship between growth and metabolism is discussed.     

Co-treatment of hydrogen sulfide and methanol in a single-stage biotrickling filter under acidic conditions

Biofiltration of waste gases is cost-effective and environment-friendly compared to the conventional techniques for treating large flow rates of gas streams with low concentrations of pollutants. Pulp and paper industry off-gases usually contain reduced sulfur compounds, such as hydrogen sulfide and a wide range of volatile organic compounds (VOCs), e.g., methanol. It is desirable to eliminate both of these groups of compounds. Since the co-treatment of inorganic sulfur compounds and VOCs in biotrickling filters is a relatively unexplored area, the simultaneous biotreatment of H2S and methanol as the model VOC was investigated. The results showed that, after adaptation, the elimination capacity of methanol could reach around 236 g m(-3) h(-1) with the simultaneous complete removal (100%) of 12 ppm H2S when the empty bed residence time is 24 s. The pH of the system was around 2. Methanol removal was hardly affected by the presence of hydrogen sulfide, despite the low pH. Conversely, the presence of the VOC in the waste gas reduced the efficiency of H2S biodegradation. The maximal methanol removal decreased somewhat when increasing the gas flow rate. This is the first report on the degradation of methanol at such low pH in a biotrickling filter and on the co-treatment of H2S and VOCs under such conditions.     

Effect of pre-treatment and supporting media on Ni(II), Cu(II), Al(III) and Fe(III) sorption by plant root material

In this work Paspalum notatum root material was used to elucidate the influence of acid leaching pre-treatment and of sorption medium on metal adsorption. Ground P. notatum root was leached with 0.14M HNO(3). Leached root material (LRM) and non-leached root material (NLRM) were employed to flow sorption of Ni(II), Cu(II), Al(III) and Fe(III) in 0.5M CH(3)COONH(4) medium at pH 6.5. For LRM the sorption was also studied in 0.5M KNO(3) medium. The acid pre-treatment increased the sorption capacity (SC) for all ions studied. For the KNO(3) medium, Cu(II) and Fe(III) sorption was higher than in CH(3)COONH(4) and the type of the Ni(II) isotherm's model changed. The Freundlich model was the most representative isotherm model to describe metallic ions sorption. The (1)H NMR spectra showed differences between LRM and NLRM and the acid-basic potentiometric titration elucidated that acid-leaching procedure affected the root material sorption sites once only two predominant sorption sites were found for LRM (phenolic and amine, both able cations sorption) and five sorption sites (two carboxylic, amine and two phenolic) were founded for NLRM.     

Acid-base properties of humic substances from composted and thermally-dried sewage sludges and amended soils as determined by potentiometric titration and the NICA-Donnan model

The acid-base properties of humic acids (HAs) and fulvic acids (FAs) isolated from composted sewage sludge (CS), thermally-dried sewage sludge (TS), soils amended with either CS or TS at a rate of 80 t ha(-1)y(-1) for 3y and the corresponding unamended soil were investigated by use of potentiometric titrations. The non-ideal competitive adsorption (NICA)-Donnan model for a bimodal distribution of proton binding sites was fitted to titration data by use of a least-squares minimization method. The main fitting parameters of the NICA-Donnan model obtained for each HA and FA sample included site densities, median affinity constants and widths of affinity distributions for proton binding to low and high affinity sites, which were assumed to be, respectively, carboxylic- and phenolic-type groups. With respect to unamended soil HA and FA, the HAs and FAs from CS, and especially TS, were characterized by smaller acidic functional group contents, larger proton binding affinities of both carboxylic- and phenolic-type groups, and smaller heterogeneity of carboxylic and phenolic-type groups. Amendment with CS or TS led to a decrease of acidic functional group contents and a slight increase of proton binding affinities of carboxylic- and phenolic-type groups of soil HAs and FAs. These effects were more evident in the HA and FA fractions from CS-amended soil than in those from TS-amended soil.     

Combination of ozonation with conventional aerobic oxidation for distillery wastewater treatment

Laboratory-scale experiments were conducted in order to investigate the effect of ozone as pre-aerobic treatment and post-aerobic treatment for the treatment of the distillery wastewater. The degradation of the pollutants present in distillery spent wash was carried out by ozonation, aerobic biological degradation processes alone and by using the combinations of these two processes to investigate the synergism between the two modes of wastewater treatment and with the aim of reducing the overall treatment costs. Pollutant removal efficiency was followed by means of global parameters directly related to the concentration of organic compounds in those effluents: chemical oxygen demand (COD) and the color removal efficiency in terms of absorbance of the sample at 254 nm. Ozone was found to be effective in bringing down the COD (up to 27%) during the pretreatment step itself. In the combined process, pretreatment of the effluent led to enhanced rates of subsequent biological oxidation step, almost 2.5 times increase in the initial oxidation rate has been observed. Post-aerobic treatment with ozone led to further removal of COD along with the complete discoloration of the effluent. The integrated process (ozone-aerobic oxidation-ozone) achieved approximately 79% COD reduction along with discoloration of the effluent sample as compared to 34.9% COD reduction for non-ozonated sample, over a similar treatment period.     

Effect of chelating agents and solubility of cadmium complexes on uptake from soil by Brassica juncea

Brassica juncea, or Indian mustard, was grown in soil artificially contaminated with either a soluble salt, CdCl(2), at 186mg Cdkg(-1), or alternately an insoluble, basic salt, CdCO(3), at 90mg Cdkg(-1). These experiments study the range of Cd uptake by Indian mustard from conditions of very high Cd concentration in a soluble form to the other extreme with an insoluble Cd salt. After plants were established, four different chelating agents were applied. Chelating agents increased plant uptake of Cd from the CdCl(2) soil but did not significantly increase plant uptake of Cd from the CdCO(3) contaminated soil. Addition of ethylenediaminetetraacetic acid (EDTA) increased the plant concentration of Cd by almost 10-fold in soils contaminated with CdCl(2), with a concentration of 1283mg Cdkg(-1) in the dried EDTA-treated plants over a concentration of 131mg Cdkg(-1) in plants without added chelate. However, EDTA increased the aqueous solubility of Cd by 36 times over the soil matrix without added chelator, and thereby, increased the possibility of leaching. Other chelators used in both experiments were ethylenebis(oxyethylenenitrilo)tetraacetic acid, trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid, and diethylenetriaminepentaacetic acid (DTPA) increasing Cd in plants to 1240, 962, and 437mg Cdkg(-1), respectively. The other chelating agents increased the solubility of Cd in the leachate but not to the extent of EDTA. Comparing all chelating agents studied, DTPA increased plant uptake in terms of Cd in dried plant concentration most relative to the solubility of complexed Cd in runoff water.     

Binding affinity of proanthocyanidin from waste Pinus radiata bark onto proline-rich bovine achilles tendon collagen type I

Binding affinity of proanthocyanidin (PA) purified from Pinus radiata bark waste onto bovine Achilles tendon collagen (type I) was studied. Adsorption of PA onto the collagen was optimized by examining pH, contact time and temperature. The adsorption was pH-dependent. The maximum adsorption capacity (Q(0)) of PA on collagen was found to be 211 mg g(-1) using the Langmuir isotherm. Comparison between two adsorbents also showed that collagen had higher adsorptivity of approximately 20% more than PVPP (polyvinyl polypyrrolidone). The high affinity between PA and collagen was further confirmed in solvent solubility experiments. The observed solvent resistance was thought to be mainly due to a hydrophobic stacking mechanism reinforced by hydrogen bonding. FT-IR spectra clearly indicated the presence of PA adsorbed on collagen. The results have interesting implications that PA can be a good protective agent for collagen against collagenase and other enzymes.     

Future climate scenarios and rainfall--runoff modelling in the Upper Gallego catchment (Spain)

Global climate change may have large impacts on water supplies, drought or flood frequencies and magnitudes in local and regional hydrologic systems. Water authorities therefore rely on computer models for quantitative impact prediction. In this study we present kernel-based learning machine river flow models for the Upper Gallego catchment of the Ebro basin. Different learning machines were calibrated using daily gauge data. The models posed two major challenges: (1) estimation of the rainfall-runoff transfer function from the available time series is complicated by anthropogenic regulation and mountainous terrain and (2) the river flow model is weak when only climate data are used, but additional antecedent flow data seemed to lead to delayed peak flow estimation. These types of models, together with the presented downscaled climate scenarios, can be used for climate change impact assessment in the Gallego, which is important for the future management of the system.     

Agricultural opportunities to mitigate greenhouse gas emissions

Agriculture is a source for three primary greenhouse gases (GHGs): CO(2), CH(4), and N(2)O. It can also be a sink for CO(2) through C sequestration into biomass products and soil organic matter. We summarized the literature on GHG emissions and C sequestration, providing a perspective on how agriculture can reduce its GHG burden and how it can help to mitigate GHG emissions through conservation measures. Impacts of agricultural practices and systems on GHG emission are reviewed and potential trade-offs among potential mitigation options are discussed. Conservation practices that help prevent soil erosion, may also sequester soil C and enhance CH(4) consumption. Managing N to match crop needs can reduce N(2)O emission and avoid adverse impacts on water quality. Manipulating animal diet and manure management can reduce CH(4) and N(2)O emission from animal agriculture. All segments of agriculture have management options that can reduce agriculture's environmental footprint.