Anaerobic PAH degradation in soil by a mixed bacterial consortium under denitrifying conditions

Polycyclic aromatic hydrocarbons (PAHs) are one of the main classes of contaminants in the terrestrial environment. Concentrations of biphenyl, fluorene, phenanthrene and pyrene were added to soil samples in order to investigate the anaerobic degradation potential of PAHs under denitrifying conditions. A mixed population of microorganisms obtained from a paddy soil was incubated for 20 days in anaerobic conditions in the presence of soil alone or with nitrate, adding, as electron donors, PAHs and, in some samples, glucose or acetate. At regular time intervals oxidation-reduction potential, PAHs concentration, microbial ATP and nitrate concentration into the solution were measured. Degradation trends for each hydrocarbon are similar under all conditions, indicating that the molecular conformation prevails over other parameters in controlling the degradation. Poor degradation results were obtained when PAHs were the only organic matter available for the inoculum, thus confirming the recalcitrance to degradation of these compounds. Biodegradation was influenced by the addition of other carbon sources. As better degradation results were generally obtained when acetate or glucose were added, the hypothesis of a co-metabolic enhancement of PAH biodegradation seems likely. Thus, anaerobic biodegradation of PAHs studied, biphenyl, fluorene, phenanthrene and pyrene, seems to be possible both through fermentative and respiratory metabolism, provided that low molecular weight co-metabolites and suitable electron acceptors (nitrate) are present.     

Evaluation of the use of bioaccumulation and biological effects tools in caged mussels,within the European Water Framework Directive

Bioaccumulation and biological effects of pollution were assessed in mussels (Mytilus galloprovincialis) caged for one month at three sites in the Oiartzun estuary (south-eastern Bay of Biscay, Spain) with the aim of evaluating their usefulness within the investigative monitoring defined in the European Union Water Framework Directive (WFD). The highest concentrations of organic contaminants determined in mussels' tissue were detected towards the inner part of the estuary but no gradient pattern was found for metal bioaccumulation. Population fitness responses measured as condition index, stress on stress and gonad index were similar in all caged mussels and did not follow the organic pollution gradient. However, biomarkers determined at tissue, cell and protein level (histopathology, micronuclei frequency, malondialdehyde levels and vitellogenin-like protein levels) revealed a higher stress syndrome at the inner part of the estuary showing signs of genotoxicity, oxidative stress and endocrine disruption. Overall, the integrated chemical–biological approach in connection with mussel caging technique proved to be a useful tool to assess environmental pollution, allowing a better understanding of the cause–effect relationship within the investigative monitoring defined in the WFD.     

Application of membrane bioreactor technology for wastewater treatment and reuse in the Mediterranean region: Focusing on removal efficiency of non-conventional pollutants

The Mediterranean Region is a semi-arid area whose land is facing serious erosion, causing adverse impacts on agriculture. To improve the water availability, researchers have proposed the reclamation and reuse of treated wastewater. In this paper, we report the main findings of 10 years of research on the efficiencies of a conventional activated sludge process and a submerged membrane bioreactor, with particular emphasis on the removal of non-conventional pollutants. The studies showed that the membrane bioreactor produced a virtually solids-free, high-quality permeate: most nutrients, heavy metals, and persistent organic pollutants were removed, and in particular, dioxins, furans, and polychlorinated biphenyls were typically present at concentrations below the detection limit. Moreover, the total coliforms count decreased by 4–5 log and Escherichia coli was absent from the membrane bioreactor permeate. These results, combined with the continuing reduction of the capital and operating costs for this approach, suggest that membrane bioreactors are an increasingly cost-effective technology to produce treated effluents that are suitable for reuse.     

Sources and distribution of polycyclic aromatic hydrocarbons in sediments from the Spanish northern continental shelf. Assessment of spatial and temporal trends

The distribution of polycyclic aromatic hydrocarbons was determined in surface sediments collected at 36 stations along the Spanish Northern continental shelf in March and September 2003, and February 2005. Concentrations of PAHs (Σ13 parent components) were in the range of 22-47528 μg/kg dw, the highest values corresponding to coastal urban-industrial hotspots and decreasing offshore. Sediment quality guidelines (SQGs) showed that concentrations of total PAHs were below the threshold effect level (TEC) in 27 stations (81%) and above in 7, two of which (Gijon and Bilbao) were above the probable effect concentration (PEC). The detailed study of diagnostic ratios suggested a rather uniform mixture of petrogenic and pyrolytic PAH sources along the continental shelf, with a slight decrease of the latter moving westwards and offshore. In order to assess the incidence of sediment sampling on the variability of the results, selected stations were also monitored in February and September 2004 and September 2005. The average field variance of the values obtained for each station was 31% that decreased to 23% when the values were normalized to TOC.     

RETRACTED ARTICLE: Perspectives for the long-term penetration of new renewables in complex energy systems: the Italian scenario

Renewable energy sources are mainly used in the electrical sector. Electricity is not a storable commodity. Hence, it is necessary to produce the requested quantity and distribute it through the system in such a way as to ensure that electricity supply and demand are always evenly balanced. This constraint is actually the main problem related to the penetration of new renewables (wind and photovoltaic power) in the context of complex energy systems. The paper analyzes some aspects in connection with the problem of new renewable energy penetration. The case of Italian scenario is considered as a meaningful reference due to the characteristic size and the complexity of the same. The various energy scenarios are evaluated with the aid of a multipurpose software taking into account the interconnections between the different energetic uses. In particular, it is shown how the penetration of new renewable energies is limited at an upper level by technological considerations and it will be more sustainable if an integration of the various energy use (thermal, mobility and electrical) field will be considered.     

Life cycle implications of urban green infrastructure

Low Impact Development (LID) is part of a new paradigm in urban water management that aims to decentralize water storage and movement functions within urban watersheds. LID strategies can restore ecosystem functions and reduce runoff loadings to municipal water pollution control facilities (WPCF). This research examines the avoided energy and greenhouse gas (GHG) emissions of select LID strategies using life cycle assessment (LCA) and a stochastic urban watershed model. We estimate annual energy savings and avoided GHG emissions of 7.3 GJ and 0.4 metric tons, respectively, for a LID strategy implemented in a neighborhood in New York City. Annual savings are small compared to the energy and GHG intensity of the LID materials, resulting in slow environmental payback times. This preliminary analysis suggests that if implemented throughout an urban watershed, LID strategies may have important energy cost savings to WPCF, and can make progress towards reducing their carbon footprint.     

Growth responses of crop and weed species to heavy metals in pot and field experiments

Greenhouse and field studies were performed to examine the growth responses and possible phytoremediation capacity towards heavy metals of several Brassicaceae (Brassica alba, Brassica carinata, Brassica napus and Brassica nigra) and Poaceae (durum wheat and barley). Soils used featured total concentrations of Cr, Cu, Pb and Zn largely exceeding the maximum levels permitted by the Italian laws. Different organic amendments were tested such as a compost and the plant growth-promoting rhizobacterium Bacillus licheniformis. In the greenhouse experiment, plant length, leaf area index and shoots dry matter were evaluated periodically for the Brassicaceae examined. Whereas plant length, grains production, weight of 1,000 seeds, ear fertility and tiller density were determined under field conditions at the end of the crop cycle for wheat and barley. In general, the species tested appeared to be tolerant to high heavy metal concentrations in soil, and slightly significant differences were found for all parameters considered. A marked growth increase was shown to occur for Brassicaceae cultivated on compost- and bacillus-amended contaminated soils, with respect to non-amended contaminated soils. With some exception, higher growth parameters were measured for wheat and barley plants cropped from contaminated soils in comparison to non-contaminated soils. Further, bacillus amendment enhanced the length of wheat and barley plants in both non-contaminated and contaminated soils, while different effects were observed for the other parameters evaluated.     

A Cost-Effectiveness Analysis of Seminatural Wetlands and Activated Sludge Wastewater-Treatment Systems

A cost-effectiveness analysis was performed to evaluate the competitiveness of seminatural Free Water Surface (FWS) wetlands compared to traditional wastewater-treatment plants. Six scenarios of the service costs of three FWS wetlands and three different wastewater-treatment plants based on active sludge processes were compared. The six scenarios were all equally effective in their wastewater-treatment capacity. The service costs were estimated using real accounting data from an experimental wetland and by means of a market survey. Some assumptions had to be made to perform the analysis. A reference wastewater situation was established to solve the problem of the different levels of dilution that characterize the inflow water of the different systems; the land purchase cost was excluded from the analysis, considering the use of public land as shared social services, and an equal life span for both seminatural and traditional wastewater-treatment plants was set. The results suggest that seminatural systems are competitive with traditional biotechnological systems, with an average service cost improvement of 2.1-fold to 8-fold, according to the specific solution and discount rate. The main improvement factor was the lower maintenance cost of the seminatural systems, due to the self-regulating, low artificial energy inputs and the absence of waste to be disposed. In this work, only the waste-treatment capacity of wetlands was considered as a parameter for the economic competitiveness analysis. Other goods/services and environmental benefits provided by FWS wetlands were not considered.

Alteration of potential harmful elements levels in sediments and biota from the central Mediterranean Sea (Aeolian Archipelago) following an episode of intense volcanic activity

In this paper levels of four (Hg, Cd, Pb, As) potential harmful elements (PHE) were measured in three different environmental matrices (sediments, macroalgae and fishes) from the Aeolian Archipelago and control areas both after 1 and 10 months from a volcanic activity of particular relevance occurred at the end of October 2002. Results were analysed on a multivariate statistical basis with the aim to evaluate: (I) general levels of pollution and increase of PHE due to the event; (II) differences observed among tested matrices in the time of recovery after the occurrence of the critical event; (III) the biological enrichment of PHE along the trophic web produced by the geological event. Results evidenced that volcanic emissions could represent a local source of particular relevance able to determine great enrichments of considered PHE in sediments and biological species. After 10 months from the event, levels in sediments and macroalgae notably decreased, whereas fish species evidenced an increase, principally related to the bioaccumulation phenomena. On the basis of the biological enrichment factors (BEF), major enrichments were evidenced after 1 month whereas, after 10 months, were recorded values reliable to an incomplete recovery. Concerning Cd, the BEF higher levels reported for the species Serranus cabrilla was probably related both to the diet and to the specific detoxification rates of this species.     

Woody residues of the grape production chain as an alternative precursor of high porous activated carbon with remarkable performance for naproxen uptake from water

Environmental Science and Pollution Research - Activated carbon prepared from grape branches was used as a remarkable adsorbent to uptake naproxen and treat a synthetic mixture from aqueous...