Modeling of perched leachate zone formation in municipal solid waste landfills

The paper presents a 1D mathematical model for the simulation of the percolation fluxes throughout a landfill for municipal solid waste (MSW). Specifically, the model was based on mass balance equations, that enable simulation of the formation of perched leachate zones in a landfill for MSW. The model considers the landfill divided in several layers evaluating the inflow to and outflow from each layer as well as the continuous moisture distribution. The infiltration flow was evaluated by means of the Darcy’s law for an unsaturated porous medium, while the moisture distribution evaluation has been carried out on the basis of the theory of the vertically distributed unsaturated flow. The solution of the model has been obtained by means of the finite difference method. The model has been applied to a semi-idealized landfill located in Palermo landfill (Bellolampo). Specifically, field measurements were conducted to determine the relationship between waste density and applied vertical strain. This relationship was then used to relate vertical strain to waste porosity. The inflow rate to the system was simulated via a synthetic hyetograph whose characteristics have been identified in a previous hydrologic study.Three simulations, each with a different initial moisture content, were conducted. The model results showed a different response of the landfill in terms both of flow rates throughout the landfill and moisture profile. Indeed, the initial moisture content drastically influenced not only the formation of perched leachate zones but also their extension. The model can be a useful tool in predicting potential for the formation of perched leachate zones.     

Beijing and beyond: women's leadership in sustainable natural resource management

We are pleased to have been asked to introduce this special issue of Natural Resources Forum dedicated to women and natural resources management. The issues discussed in the articles on water and energy resources, artisanal mining and sanitation, and how women can improve the management of their environment, were among the key concerns expressed at the Fourth World Conference on Women held in Beijing in September 1995.     

Evaluation of methane emissions from Palermo municipal landfill: Comparison between field measurements and models

Methane (CH₄) diffuse emissions from Municipal Solid Waste (MSW) landfills represent one of the most important anthropogenic sources of greenhouse gas. CH₄ is produced by anaerobic biodegradation of organic matter in landfilled MSW and constitutes a major component of landfill gas (LFG). Gas recovery is a suitable method to effectively control CH₄ emissions from landfill sites and the quantification of CH₄ emissions represents a good tool to evaluate the effectiveness of a gas recovery system in reducing LFG emissions. In particular, LFG emissions can indirectly be evaluated from mass balance equations between LFG production, recovery and oxidation in the landfill, as well as by a direct approach based on LFG emission measurements from the landfill surface. However, up to now few direct measurements of landfill CH₄ diffuse emissions have been reported in the technical literature. In the present study, both modeling and direct emission measuring methodologies have been applied to the case study of Bellolampo landfill located in Palermo, Italy. The main aim of the present study was to evaluate CH₄ diffuse emissions, based on direct measurements carried out with the flux accumulation chamber (static, non-stationary) method, as well as to obtain the CH₄ contoured flux map of the landfill. Such emissions were compared with the estimate achieved by means of CH₄ mass balance equations. The results showed that the emissions obtained by applying the flux chamber method are in good agreement with the ones derived by the application of the mass balance equation, and that the evaluated contoured flux maps represent a reliable tool to locate areas with abnormal emissions in order to optimize the gas recovery system efficiency.     

Impacts of UV-B radiation on short-term cultures of sea urchin coelomocytes

Three specialized cell types constitute the heterogeneous population present in the coelomic cavity fluid of sea urchins. The list includes: phagocytes, which undergo a stress-induced petaloid-filopodial transition, white or red amoebocytes and vibratile cells. As a whole, they act as the immune defense system of the sea urchin and respond to environmental and experimental challenge triggering specific stress markers. Here we extended our studies on coelomocytes short-term cultures by describing the morphology and occurrence of each cell type and analyzing their response to UV-B radiation at the biochemical level and with respect to DNA damage. The effects of different doses, ranging from 500 to 2,000 J/m², on cells, which were then cultured in vitro for 1–6 h were tested. As early as 1 h after irradiation we found an increase in the levels of the heat shock protein70 (hsp) stress marker. A peak at 1,000 J/m² corresponding to a 3.4-fold hsp70 increase over the levels of control coelomocytes was observed. Concurrently, we found an increase in the number of apoptotic nuclei detected by Hoechst staining, which varied from 7.1 to 15.6% in cells that were exposed to 500 and 2,000 J/m², respectively. On the basis of our findings we confirm sea urchin coelomocytes as a sensitive cell culture system for environmental studies and propose their use for the analysis on the effects of UV-B radiation. Physical and Chemical Impacts on Marine Organisms, a Bilateral Seminar Italy-Japan held in November 2004. This paper is dedicated to the memory of Aurelia Koros, Ph. D., University of Pittsburg, who committed her scientific life to the study of natural killer cell antigens expressed in small lung carcinoma cells and sea urchin coelomocytes.     

Including spatial contiguity information in the analysis of multispecific patterns

In this paper we analyse an ordination method in which spatial contiguity information is included. The original method, proposed by Ver Hoef and Glenn-Lewin (1989), is extended, using graphs to describe spatial contiguity for several sampling schemes where locations are given. Extensions for two dimensional grids and for the case of discrete measures of abundance are analysed. Applications to simulated transect frequency data and real data collected on a regular grid are reported.     

Acetylcholinesterase activity is affected by stress conditions in<Emphasis Type="Italic"> Paracentrotus lividus</Emphasis> coelomocytes

The presence and function of acetylcholinesterase (AChE) in blood cells and plasma is well known. The enzyme activity is associated to red blood cell membranes, as well as to the perinuclear region of leucocytes, suggesting a role in the function of the latter. Recently coelomocytes, acknowledged progenitors of immune cells in vertebrate systems, have been shown to respond to stress conditions, both in laboratory experiments and field studies. Bearing in mind the similarity between coelomocytes and vertebrate blood cells, we investigated the presence of AChE activity in coelomocytes of the sea urchin Paracentrotus lividus characterized by specific inhibitors, in relation to cold stress induced in the laboratory. Exposure to stress was followed by electrophoretic analysis of AChE activity and Western blot analysis of AChE-like immunoreactivity. Moreover, quantitative analysis of the different molecular forms of AChE was carried out with the aid of a spectrophotometric method. The effects of stress on AChE activity were time dependent. In fact, the enzyme activity was detected by the catalytic activity in cleaving the substrate acetyl thiocholine iodide, which appears to be formed by different isoforms of the enzyme, compared to that of Electrophorus, which was used as a control. Western blot analyses showed the presence of different immunoreactive molecules, with molecular mass ranging from 265 kDa (corresponding to Electrophorus molecules) to about 180 kDa. According to quantitative analysis, the isoforms that were differentiated corresponded to an AChE with the capacity to cleave acetyl--methyl thiocholine iodide (the so-called true AChE, E.C. 3.1.1.7, corresponding to the 265 kDa band) and to a ChE with the capacity to cleave propionyl thiocholine iodide as well. The latter is an ancestral form of AChE, mainly present in invertebrates. Each of these forms was affected differently by varying time exposures.Communicated by R. Cattaneo-Vietti, Genova     

Mobilization of innovation and investment resources for environmental management in Russian federation regions

Investments in environmental management and environmental protection have a decisive influence on the future of a region and its place in the economic development of the country as a whole. In this article, the principal differences between investment in environmental management and the financing of other projects are discussed. It is proven that, at present, the investment policy in the field of environmental protection of a region is oriented primarily toward current results. In such cases, it is possible to achieve only short‐term goals, and ultimately, to miss the prospect of further conservation of resources. Hence, short‐term investments in environmental protection activities and the achievement of rapid results are replaced by the commitment to promising, long‐term strategic growth. This article notes that the most effective form of implementing environmental monitoring is through environmental auditing, as auditing is performed at the expense of customers and does not require public financing. Furthermore, the effects of implementing environmental policies based on the results of environmental auditing can be even more significant than the results achieved under the State's environmental protection measures     

Organochlorine pesticides and polychlorinated biphenyls in common buzzard (<Emphasis Type="Italic">Buteo buteo</Emphasis>) from Sicily (Italy)

In the present study, we investigated the concentrations and distribution of organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) in intestine, liver, and muscle samples of 11 common buzzards (Buteo buteo) from Sicily used as bioindicator for monitoring pollution in environment. All samples of common buzzards were collected at the “Recovery Center of Wild Fauna” of Palermo, through the Zooprophilactic Institute. Quantitative determination of OCs and PCBs in the samples examined has been carried out using HRGC-ECD and GC-MS. The results obtained show the presence of concentrations of ∑DDT and ∑PCB in almost all samples. Regarding ∑DDT (4,4^′-DDE, 2,4^′-DDD, 4,4^′-DDD, 2,4^′-DDT, and 4,4^′-DDT), the highest concentrations were found in intestine (0.411 ± 0.050 μg/g) followed by muscle (0.130 ± 0.017 μg/g) and liver samples (0.109 ± 0.014 μg/g). As regards the ∑PCB congeners (PCB-28, PCB-52, PCB-95, PCB-99, PCB-101, PCB-110, PCB-138, PCB-146, PCB-149, PCB-151, PCB-153, PCB-170, PCB-177, PCB-180, PCB-183, and PCB-187), the highest concentrations were found in intestine (1.686 ± 0.144 μg/g) followed by liver (1.064 ± 0.162 μg/g) and muscle samples (0.797 ± 0.078 μg/g). Our data deserve particular attention not only for their significance but especially because they were recorded in Sicily, a region with a very low risk of environmental pollution due to the shortage of industries.