Deborah Traversi

Application of a real-time qPCR method to measure the methanogen concentration during anaerobic digestion as an indicator of biogas production capacity

Biogas is an energy source that is produced via the anaerobic digestion of various organic materials, including waste-water sludge and organic urban wastes. Among the microorganisms involved in digestion, methanogens are the major microbiological group responsible for methane production. To study the microbiological equilibrium in an anaerobic reactor, we detected the methanogen concentration during wet digestion processes fed with pre-treated urban organic waste and waste-water sludge. Two different pre-treatments were used in successive experimental digestions: pressure-extrusion and turbo-mixing. Chemical parameters were collected to describe the process and its production. The method used is based on real-time quantitative PCR (RT-qPCR) with the functional gene mcrA as target. First, we evaluated the validity of the analyses. Next, we applied this method to 50 digestate samples and then we performed a statistical analysis. A positive and significant correlation between the biogas production rate and methanogen abundance was observed (r = 0.579, p < 0.001). This correlation holds both when considering all of the collected data and when the two data sets are separated. The pressure-extrusion pre-treatment allowed to obtain the higher methane amount and also the higher methanogen presence (F = 41.190, p < 0.01). Moreover a higher mean methanogen concentration was observed for production rate above than of 0.6 m(3) biogas/kg TVS (F = 7.053; p < 0.05). The applied method is suitable to describe microbiome into the anaerobic reactor, moreover methanogen concentration may have potential for use as a digestion optimisation tool.

Mutagenic properties of PM2.5 urban pollution in the Northern Italy: the nitro-compounds contribution.

PM2.5 is the breathable fraction of the particulate matter and some adverse health effects, such as respiratory functionality, cardiological diseases and cancer, can be in some measure attributable to this risk factor exposure. Some of the most carcinogen compounds transported by PM2.5 are nitro-compounds. In this study, a strengthened in vitro bioassay--able to predict the mutagenic/carcinogenic activity of the environmental mixtures--was conducted on PM2.5 organic extracts to define the nitro-compounds burden. PM2.5 air pollution was daily monitored, during 2006, in three cities located in the Northern part of Italy (Torino, Pavia and Verona) and the mutagenic properties of the PM2.5 organic extracts were assessed with the Ames test. The bacterial used in this study were three Salmonella typhimurium strains: TA98, nitroreductase-less mutant TA98NR and YG1021 carrying a nitroreductase-producing plasmid. The annual PM2.5 mean level measured in Torino was 46.5 (+/-31.6) microg/m(3), in Pavia 34.8 (+/-25.1) microg/m(3), and in Verona 37.3 (+/-27.8) microg/m(3), while the mutagenicity expressed as TA98 net reverants/m(3) was 28.0 (+/-22.1), 28.3 (+/-24.9), and 34.2 (+/-30.9) respectively. Monthly pool bioassays, conducted with the three different strains, showed a greater mutagenic response of the YG1021 in each city. The relationship among the mutagenic answers for YG1021:TA98:TA98NR was about 6:3:1 (p<0.001). Over nitroreductase activity enhanced the response of 2.2, 2.0 and 1.7 times for Torino, Pavia, and Verona (ANOVA Torino p<0.05) respectively. Without nitroreductase activity the genotoxicity was limited. These biological findings are able to describe a relevant role played by the nitro compounds in the mutagenic properties of the urban PM2.5 in the Padana plain; moreover the bacterial nitroreductase plays a predominant role in DNA interaction primarily for Torino PM2.5 extracts.

The role of different methanogen groups evaluated by Real-Time qPCR as high-efficiency bioindicators of wet anaerobic co-digestion of organic waste

Methanogen populations and their domains are poorly understood; however, in recent years, research on this topic has emerged. The relevance of this field has also been enhanced by the growing economic interest in methanogen skills, particularly the production of methane from organic substrates. Management attention turned to anaerobic wastes digestion because the volume and environmental impact reductions. Methanogenesis is the biochemically limiting step of the process and the industrially interesting phase because it connects to the amount of biogas production. For this reason, several studies have evaluated the structure of methanogen communities during this process. Currently, it is clear that the methanogen load and diversity depend on the feeding characteristics and the process conditions, but not much data is available. In this study, we apply a Real-Time Polymerase Chain Reaction (RT-PCR) method based on mcrA target to evaluate, by specific probes, some subgroups of methanogens during the mesophilic anaerobic digestion process fed wastewater sludge and organic fraction of the municipal solid waste with two different pre-treatments. The obtained data showed the prevalence of Methanomicrobiales and significantly positive correlation between Methanosarcina and Methanosaetae and the biogas production rate (0.744 p < 0.01 and 0.641 p < 0.05). Methanosarcina detected levels are different during the process after the two pre-treatment of the input materials (T-test p < 0.05). Moreover, a role as diagnostic tool could be suggested in digestion optimisation.

Cotinine and N-(2-hydroxyethyl)valine as markers of passive exposure to tobacco smoke in children

Large segments of populations, including children, are exposed to environmental tobacco smoke (ETS), a risk factor for lung cancer and heart, circulatory and respiratory diseases. Recently, ETS was classified as a class A carcinogen by USEPA, as carcinogenic to humans by IARC (group 1) and by the National Toxicology Program of the US National Institutes of Health. Cotinine, a product of the metabolism of nicotine, is measurable in urine and, correlates strictly and directly to ETS exposure, therefore representing a well-known internal dose marker. Another marker of active tobacco smoking is the N-(2-hydroxyethyl) valine (HOEtVal) which results from the reaction between ethylene oxide (EtO) and the N-terminal valine of hemoglobin. The aim of this study was the evaluations of ETS markers, namely urinary cotinine and HOEtVal measured in blood in 100 children with ages ranging between 3 and 13 years. Experimental findings show that cotinine, as a specific internal dose marker, and HOEtVal, as a nonspecific biological effective dose marker, both depend on the passive exposure to ETS as well as on the active habit of smoking.

Chemical characterisation and cytotoxic effects in A549 cells of urban-air PM10 collected in Torino, Italy.

Human type II alveolar cells (A549) were exposed to aqueous- and organic-solvent PM10 extracts to evaluate their effects on cell proliferation, proinflammatory cytokine release and cytotoxicity (assayed by lactate dehydrogenase, LDH, activity). PM10 samples collected in Torino (northwest Italy) were analysed for inorganic chemical species (bioavailable iron and secondary particulates) and endotoxins, which are potentially inflammatory promoters in human airways. During the sampling period, PM10 concentration was 55.4±39.1μg/m(3), secondary particles constituted 42±9% of the PM10 total mass, and bioavailable iron concentration was 0.078±0.095μg/m(3). PM10 inhibits cell proliferation and induces both IL-6 and LDH release in a dose- and time-dependent manner, with a seasonal trend. The different effects of aqueous and organic PM10 extracts demonstrate the importance of particle composition for the induction of cytotoxic effects on A549 cells. A first comparison between the biological effects induced by PM10 extracts and PM10 components was performed.

Environmental Advances Due to the Integration of Food Industries and Anaerobic Digestion for Biogas Production: Perspectives of the Italian Milk and Dairy Product Sector

Anaerobic digestion (AD) is a biotechnology that is able to produce an energy vector from waste organic materials. Its inclusion in the food industries, especially if farming activities are present, represents an interesting perspective. This work reviews the main aspects of the inclusion of AD in milk and dairy production. It includes an analysis of the sector characteristics in terms of diffusion, a discussion of waste production and disposal concerning milk and dairy production, a description of the biological and technological aspects of AD, a discussion regarding the application of AD for milk by-products, a description of environmental and legislative aspects, and the suggestion of an integrated model that includes the anaerobic co-digestion of whey and cattle slurry in the milk and dairy production industries. Both environmental and economic impacts of such integration promise to pay for the preliminary investment in AD plant installation and the development of additional expertise.

Torino 2006 Winter Olympic Games: Highlight on Health Services Organization

BACKGROUND Mass gatherings require attention toward planning and execution of dedicated medical care. OBJECTIVES The aims were to describe the organization and provision of medical care in the Torino 2006 Winter Olympic Games in light of the epidemiology of illnesses and injuries among athletes during this event. METHODS The organization integrated 18 medical centers operating at Olympic venues, three polyclinics inside the Olympic Villages, and 13 pre-existing Olympic Hospitals. The design was a retrospective study, with review of medical records at Olympic medical facilities. All the athletes who attended any medical center or polyclinic were eligible. The main outcomes included type of injuries and illnesses affecting athletes, incidence of injuries and illnesses by provenance and discipline, and rate of hospital admissions. RESULTS A total of 330 athletes received medical care and 676 medical encounter forms were documented, with an overall medical utilization rate of 12.66%. Skeleton, snowboard, bobsleigh, and alpine and freestyle skiing had the highest medical attendance rate relative to other disciplines (p < 0.001). The majority of injuries and illnesses were of a minor nature. A total of 23 visits required hospital admissions (3.40%). CONCLUSION The described model of medical coverage for such events seemed to be practical and efficient for the athletes, without depleting services to the general population. The risk of severe injury and illness seemed to be low. These data could be useful for planning medical services in future mass gatherings.

Microbial-chemical indicator for anaerobic digester performance assessment in full-scale wastewater treatment plants for biogas production

Anaerobic digestion was introduced into wastewater treatment plants several years ago, but anaerobic digestion performance has not yet been achieved. The variability of the microbial community in digesters is poorly understood, and despite the crucial role of anaerobic digestion reactors, the microbial equilibrium that yields the best performance in these reactors has only recently been hypothesised. In this study, two full-scale continuous anaerobic reactors, placed in Torinos main wastewater treatment plant in northern Italy, were followed to develop a summary indicator for measuring anaerobic digestion performance. A total of 100 sludge samples were collected. The samples were characterised chemically and physically, and microbial groups were quantified by qRT-PCR. A chemical biological performance index strictly correlated to specific biogas production (rho=0.739, p<0.01) is proposed. This approach will produce new management tools for anaerobic digestion in wastewater treatment plants.

Artificial Turf Football Fields: Environmental and Mutagenicity Assessment

The public has recently raised concerns regarding potential human health and environmental risks associated with tire crumb constituents in the artificial turf of football fields. The aim of the present study was to develop an environmental analysis drawing a comparison between artificial turf football fields and urban areas relative to concentrations of particles (PM10 and PM2.5) and related polycyclic aromatic hydrocarbons (PAHs), aromatic hydrocarbons (BTXs), and mutagenicity of organic extracts from PM10 and PM2.5. No significant differences were found between PM10 concentrations at an urban site and on a turf football field, both during warm and in cold seasons, either with or without on-field activity. PM2.5 concentrations were significantly greater at the urban site in the cold season as was the ratio of PM2.5 to PM10. BTXs were significantly greater at urban sites than on turf football fields on both on warm and cold days. The ratio of toluene to benzene (T/B ratio) was always comparable with that of normal urban conditions. The concentration of PAHs on the monitored football fields was comparable with urban levels during the two different sampling periods, and the contribution of PAHs released from the granular material was negligible. PM10 organic extract mutagenicity for artificial turf football fields was greater, whereas PM2.5 organic extract mutagenicity was lower, compared with the urban site studied. However, both organic extract mutagenicity values were comparable with the organic extract mutagenicity reported in the literature for urban sites. On the basis of environmental monitoring, artificial turf football fields present no more exposure risks than the rest of the city.

Aero-dispersed mutagenicity attributed to particulate and semi volatile phase in an urban environment

Commonly the atmospheric pollution research is focussed on particulate indicators especially when mutagenicity was studied. On the other hand the volatile and semi-volatile compounds no adsorbed on to the particles can be genotoxic and mutagenic. Moreover some mutagenic compounds, such as polycyclic aromatic hydrocarbons, are present both in the particulate and in the gas-phase in according to chemical conditions. This work is focussed on the assessing of the total mutagenicity shifting the gas-phase and particulate phase, during two seasons, in Turin. Two sampling sessions are conducted for total particulate matter and gas-phase pollutants. Moreover meteorological and usual air pollution monitoring data were collected at the same sampling station. The Salmonella assay using the strains TA98 and YG1021 was conducted on each organic extract. The mean level of total suspended particles, PM10 and PM2.5 were 73.63±26.94, 42.85±26.75 and 31.55±26.35 μg m(-)(3). The observed mutagenicity was PM induced YG1021>PM induced TA98>PM induced TA98+S9≫non-particle induced YG1021>non-particle induced TA98>non-particle induced TA98+S9. The multivariate regression is significant when we consider air pollution and meteorological indicators and chemical conditions as predictors.