Regression Analysis Model Applied to Biomonitoring Studies

A regression model is proposed for studying the relationship between trace metals concentrations and weights of individuals of Monodonta turbinata (Born), a gastropod mollusc used as a trace metal biomonitor of marine coastal areas. The model herein presented was developed including sites as reference factors and showed very good correlations. The prevision model of contamination gave good results for this kind of pollutants, and it can be used as a tool for monitoring programmes.     

Evaluation of a simultaneous sampling method of PAHs, PCDD/Fs and dl-PCBs in ambient air

The Stockholm Convention on Persistent Organic Pollutants (POPs) was signed in May 2001 by 127 countries. Currently, 12 substances are regulated by the convention, and the work on finding new candidate chemicals to the convention has started. Among these 12 substances, dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) are the objects of this study. There are no European standard methods for the simultaneous determination of these microorganic compounds, together with polycyclic aromatic hydrocarbons (PAHs) in ambient air--they must be referred to three different methods developed by the U.S. Environmental Protection Agency (EPA). The quali-quantitative analysis of these microorganic pollutants is an important challenge due to the low concentrations at which they may be present. In this study, the development of a simplified, alternative, fast and affordable sampling method for the determination of PAHs, PCDDs, PCDFs and PCBs in ambient air was performed. The sampling time was extended from 24 h to 7 d in order to enrich the sample, to fall within the instrumental limits of detection and to reduce the number of samples to be processed and, therefore, errors that may arise. First of all, experiments with labelled standards were conducted in the research area of Montelibretti (rural station, which is sited about 20 km northeast of Rome), with the purpose of optimizing sampling efficiency. Finally, the method was applied to the analysis of these compounds in the air of a suburban area with small industrial plants in order to evaluate the feasibility of the proposed sampling method system, by comparing concentrations of native compounds acquired during simultaneous daily and weekly sampling.     

Are Roadkill Hotspots in the Cerrado Equal Among Groups of Vertebrates?

Environmental Management - Understand the spatial distribution of wildlife roadkill is necessary to design mitigation measures minimizing damage to the fauna and the human population. Thus, we...     

Ambient monitoring of asbestos in selected Italian living areas

This paper presents the results of an intensive monitoring activity of the particulate, fall-out and soil of selected living areas in Italy with the aim to detect the asbestos concentration in air and subsequent risk of exposure for the population in ambient living environments, and to assess the nature of the other mineral phases composing the particulate matrix. Some areas were sorted out because of the presence of asbestos containing materials on site whereas others were used as blank spots in the attempt to detect the background environmental concentration of asbestos in air. Because the concentration of asbestos in ambient environments is presumably very low, and it is well known that conventional low–medium flow sampling systems with filters of small diameter (25 mm) may collect only a very small fraction of particulate over a short period, for the first time here, an intense monitoring activity was conducted with a high flow sampling system. The high flow system requires the use of large cellulose filters with the advantage that, increasing the amount of collected dust, the probability to collect asbestos fibers increases. Both the protocol of monitoring and analysis are novel and prompted by the need to increase the sensitivity towards the small number of expected fibers. With this goal, the collection of fall-out samples (the particulate falling into a collector filled with distilled water during the monitoring shift) and soil samples was also accomplished. The analytical protocol of the matrix particulate included preliminary X-ray powder diffraction (XRPD), optical microscopy and quantitative electron microscopy (SEM and TEM). Correlations with climatic trends and PM10 concentration data were also attempted.The surprising outcome of this work is that, despite the nature of the investigated site, the amount of dispersed asbestos fibers is very low and invariably lower than the theoretical method detection limits of the SEM and TEM techniques for identification and counting of asbestos fibers. The results are compared to the literature data worldwide and an updated model for asbestos fibers dispersion in ambient environments is proposed.     

From laboratory simulation to scale-up and design of spray barriers mitigating toxic gaseous releases

Simulation of a process by means of physical models at a reduced scale is an essential tool in many application, allowing to perform a large number of experimental runs, so as to obtain a quantitative representation of the involved phenomena, at relatively low cost. Some difficulties can arise when the mathematical model derived from the simulation is applied to a real scale problem, in that the scaling of some empirical coefficients with the system size is not obvious at all. As fluid barrier scaling is a difficult task, still not deeply investigated in the scientific literature, the focus of this study is to translate knowledge from research on this topic into practice for industrial application. Following an extensive and accurate experimental work in wind tunnel, the main parameters determining the effectiveness of containment, absorption and dilution of chlorine releases were determined and a mathematical model is developed. In order to frame proper scale-up strategies, the most important result of this study rests on the explicit formulae giving, as a function of the aforesaid parameters, the single pass efficiency, the global absorption efficiency, and the toxic gas concentration downwind the barrier. In the far field, the gas concentration is practically determined only by the rate of atmospheric dispersion of the mass flow-rate of gas escaping the abatement. The absorption efficiencies are related to the drop size and to the mass transfer coefficients in the gas and liquid phases. The mean drop diameter plays an essential role in the absorption efficiency, since it simultaneously acts on air entrainment, interfacial surface and mass transfer coefficient in the gas phase. The evaluation of the mitigation effect for an industrial installation requires the scaling of the entrainment coefficient experimentally determined from wind tunnel testing. All the scaling criteria needed for adapting the proposed model to the design of a spray curtain suitable for the protection from a chlorine release, are amply discussed presenting some carefully designed simulations. Owing to its rather general structure, the model can be applied to different gaseous releases and/or absorbing solutions, provided that proper values of the parameters related with the chemical and physical absorption of the involved substances be theoretically or experimentally obtained in advance.     

Ergonomics and Work Organization: The Relationship Between Tayloristic Design and Workers’ Health in Banks and Credit Cards Companies

Abstract

The discussion developed in this paper is based on the results of an ergonomic work analysis carried out with attendants at call centers. Some critical issues and difficulties, like working pace, inadequate tools and workstations, and software inadequacies were detected in working situations. Operator-customer interactions are presented, attempting to put in evidence working constraints, working conditions, and their connection with health problems.

The main conclusion is that serving clients, especially when the job is to provide information, is not a simple task, as information is not always available in the computerized system and is completely fragmented. The scope of workers’ actions is very restricted and complicated and recurrent requests are redirected to others. Workers (individually or as groups) have limited possibilities to make adjustments to be able to give more adequate and personalized treatment to clients and, at the same time, to work in a less stressful environment. In periods of increased workload and work intensification, the situation is very much favorable to the incidence of health disorders, such as work related musculoskeletal disorders (WMSD) and others. Some suggestions to improve the work situation are discussed.     

Improving an algorithm for classifying error types of front-line workers: Insights from a case study in the construction industry

The objective of this study was to propose improvements in an algorithm for classifying error types of front-line workers. The improvements involved: (a) making recommendations on organizing the data needed to apply the algorithm (e.g. identify actions and decisions that may serve as a reference for analysing the types of errors) and (b) drawing up guidelines for interpreting the questions that are part of the algorithm (e.g. how to define what counts as a procedure). The improvements were identified on the basis of testing the algorithm on construction sites, an environment in which it had not yet been implemented. Thus, 19 occupational accidents which had occurred in a small-sized construction company were investigated and the error types of both workers who had been injured and crew members were classified. The accidents investigated were used as a basis both to illustrate how the improvements proposed should be put in practice and to illustrate how practical insights for safety management might be derived from the algorithm.     

Accumulation and metal fluxes in the central Venice Lagoon during the last century

Samples from 18 short sediment cores were analyzed for major and trace metals (Al, Fe, Ca, K, Mg, Mn, Si, Ti, Pb, Zn, Cu, Ni, and Cr), ²¹⁰Pb, ¹³⁷Cs, total organic carbon, grain size, and mineralogical composition to find the record of major environmental changes, either natural or anthropogenic, and to establish their chronologies. Some sediments are characterized by nearly constant composition over time, but others clearly show signs of an increasing marine influence, as an increase of the carbonate contents, after the opening of the Malamocco-Marghera Canal in 1969. These changes sometimes obscure the real pattern of pollutants and tracers, which is revealed by normalization against Al. Zn is the most important contaminant, with concentration factors up to 9.3 times the background level, and the most contaminated sediments are those within a few kilometers from the industrial district of Porto Marghera. ²¹⁰Pb activity-depth profiles were used to calculate apparent accumulation rates that provide a basis for the assessment of metal fluxes. The sediments of several sites show a significant increase in anthropogenic metal contamination starting from the second decade of last century, with maximum inputs from 1930 to 1970. The decrease of heavy metal concentrations observed in surficial sediments of some sampling sites could be related to a recent reduction of pollutant inputs.     

Particulate Organic Matter Composition in A Semi-Enclosed Marine System

Spatial and temporal changes in the biochemical composition of particulate organic matter in a semi-enclosed marine system (Stagnone di Marsala, Mediterranean Sea) were studied, on a monthly basis, from January to December 1994, in order to assess nutritional value of suspended particles for benthic suspension feeders. According to previous findings, the study site displayed a strong oligotrophy. Chlorophyll-a accounted for a very low fraction of the total suspended matter pool (0.1%), whereas at least 75% of POC was of detrital/heterotrophic origin. POC: PON ratio values indicate that bacterioplankton biomass accounted for a significant fraction of the total POC pool, displaying values comparable to those of the phytoplankton biomass (phytoplankton to bacterial biomass ratio was about (1). Temporal and spatial changes in the biochemical composition of particulate organic matter were rather limited and related to its sources, the main of which is represented by detrital particles released by the Posidonia oceanica (L.) beds. the comparison between our results and those encountered in other coastal lagoons indicates that the low abundance of suspension-feeding organisms observed in the study area is related to the “quality depression” of particles due to the dilution of high quality compounds (i.e., biopolymeric carbon) in a largely inorganic matrix. This result leads us to conclude that, to reach the same amount of high quality particulate food, a suspension feeder mollusc in the Marsala lagoon would need to filter a sea water volume around 3 times higher than in other Mediterranean coastal lagoons.