Source Apportionment in the Town of La Spezia (Italy) by Continuous Aerosol Sampling and PIXE Analysis

We describe the results of an aerosol sampling campaign performedin 1999 in the medium-size industrial town of La Spezia, in theNorthwest of Italy. We used two-stage continuous streakersamplers in three different sites and periods of the year. This kind of samplers allows the separation of the PM₁₀ andPM_2.2 fractions of the particulate matter. Moreover, the hourly resolution in the aerosol collection is particularly useful inan urban environment where, typically, many pollution sourceswith fast variations are present. Up to 1700 samples have beenanalysed by Particle Induced X-ray Emission (PIXE) at the INFNaccelerator facility in Florence, obtaining hourly concentrationfor about 20 elements from Na to Pb, with a sensitivity rangingfrom below 1 to about 10 ng m^-3. The total hourly aerosolmass has been estimated with an optical analysis of the samesamples performed (before the PIXE analysis) by an equipment designed and mounted in Genoa. An extensive statistical analysisof the data included standard and Absolute Principal ComponentFactor Analysis (PCFA and APCFA) to deduce the compositionand the weight of the major aerosol sources in both fractions.Thorough different statistical approaches, we generally resolvedcontributions from vehicle emission, fossil fuel combustion,soil-road dust and sea salt aerosol.     

Greenhouse gases emission from municipal waste management: The role of separate collection

The municipal solid waste management significantly contributes to the emission in the atmosphere of greenhouse gases (e.g. CO₂, CH₄, N₂O) and therefore the management process from collection to treatment and disposal has to be optimized in order to reduce these emissions. In this paper, starting from the average composition of undifferentiated municipal solid waste in Italy, the effect of separate collection on greenhouse gases emissions from municipal waste management has been assessed. Different combinations of separate collection scenarios and disposal options (i.e. landfilling and incineration) have been considered. The effect of energy recovery from waste both in landfills and incinerators has also been addressed. The results outline how a separate collection approach can have a significant effect on the emission of greenhouse gases and how wise municipal solid waste management, implying the adoption of Best Available Technologies (i.e. biogas recovery and exploitation system in landfills and energy recovery system in Waste to Energy plants), can not only significantly reduce greenhouse gases emissions but, in certain cases, can also make the overall process a carbon sink. Moreover it has been shown that separate collection of plastic is a major issue when dealing with global warming relevant emissions from municipal solid waste management.     

New frontiers for sustainability: emergy evaluation of an eco-village

The emergy analysis was used to evaluate the sustainability of a village which aims to be ecologically friendly. The choice of focusing on the use of local resources including agriculture and farm goods, photovoltaic panels, renewable heating and cooling systems, recycled water from constructed wetlands etc., aims to obtain a sustainable village. Indices and ratios based on emergy flows have been calculated and used to evaluate the behaviour of the whole system. Their dependence upon the fraction of renewable and non renewable inputs as well as locally available versus purchased inputs from outside is stressed. A new index of sustainability (SI) is also applied to the case study. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue.     

Preferential retention of POPs on the northern aspect of mountains

Soils are the main reservoirs of POPs in mountain ecosystems, but the great variability of the concentrations, also at small scale, leaves some uncertainties in the evaluation of environmental burdens and exposure. The role of the aspect of the mountain side and the seasonal variation in the contamination levels was analysed by means of several soil samples taken from central Italian Alps. A greater contamination content was present in northern soils with a mean ratio between the north vs. south normalised concentration of around a factor of 2 (North-South Enrichment Factor). Experimental factors agreed with theoretical calculations based on temperature-specific calculated K_sa values. From May to November consistent differences in normalised concentrations up to 5-fold were observed. A dynamic picture of the POP contamination in high altitudinal soils is derived from the data in this work, with spring-summer half-lives between 60 and 120 days for most of the compounds.     

Assisted phytoremediation of mixed metal(loid)-polluted pyrite waste: effects of foliar and substrate IBA application on fodder radish

Exogenous application of plant-growth promoting substances may potentially improve phytoremediation of metal-polluted substrates by increasing shoot and root growth. In a pot-based study, fodder radish (Raphanus sativus L. var. oleiformis Pers.) was grown in As-Zn-Cu-Co-Pb-contaminated pyrite waste, and treated with indolebutyric acid (IBA) either by foliar spraying (10 mg L⁻¹), or by direct application of IBA to the substrate (0.1 and 1 mg kg⁻¹) in association, or not, with foliar spraying. With the exception of foliar spraying, IBA reduced above-ground biomass, whilst direct application of IBA to the substrate surface reduced root biomass (−59%). Trace element concentrations were generally increased, but removals (mg per plant) greatly reduced with IBA application, together with greater metal leaching from the substrate. It is concluded that, in our case, IBA had a negative effect on plant growth and phytoextraction of trace elements, possibly due to unsuitable root indoleacetic acid concentration following soil IBA application, the direct chelating effect of IBA and the low microbial activity in the pyrite waste affecting its breakdown.     

Co-production of hydrogen and electricity with CO2 capture

Electricity and hydrogen can be used as energy carriers to reduce emissions of CO₂ from small and mobile energy users. One of the most promising technologies for the production of electricity and hydrogen with low CO₂ emissions is coal gasification with CO₂ capture and storage. Performance and cost data are presented for plants which produce electricity and hydrogen alone and plants which co-produce both of these energy carriers. The co-production plants include plants which produce a fixed ratio of hydrogen to electricity and plants which are able to vary the ratio while continuing to operate the gasification and CO₂ capture parts of the plant at full load. The paper also assesses the ability of these types of plants to satisfy the varying demands for hydrogen and electricity in future energy supply systems. The lowest cost option for the scenarios assessed in the paper is the use of flexible co-production plants with underground buffer storage of hydrogen.