Effects of environmental parameters on the oxygen consumption of four marine invertebrates: a comparative factorial study

The oxygen consumption curves of two decapod crustaceans (Palaemon serratus, Penaeus monodon) and two prosobranch molluscs (Trunculariopsis trunculus, Nassarius mutabilis) have been detected in the entire pO₂ interval from 0 to 160 mmHg, under different conditions of temperature and salinity. From the experimental curves, physiological parameters such as the initial oxygen consumption velocity, the Q ₁₀ values and the oxygen independence indices have been measured. The latter parameters have been obtained using normalised plots which allow their better evaluation. The effects of temperature, salinity and oxygen partial pressure on the oxygen-consumption features have been studied using a factorial experimental plan which allows measurement of the effects of each experimental variable as well as the effects of synergistic interactions between different variables. Received: 27 March 2000 / Accepted: 13 November 2000     

Liquid household hazardous wastes in the United States: Identification,disposal, and management plan

Present methods of disposal of today's hazardous household chemicals in the United States are frequently not acceptable because of pathways to groundwater, surface water, and the atmosphere. This report identifies potentially hazardous liquid waste in the household, notes current disposal practices, and recommends an improved management plan that utilizes consumer education, manufacturer cooperation, and governmental intervention. Laws requiring uniform disposal labeling on packaging are critical. Local, county, and state governments must be encouraged to coordinate the necessary infrastructure. Managing hazardous household wastes now will mitigate potential disposal problems.     

Results from Three Field Tracer Experiments on the Neighbourhood Scale in the City of Birmingham UK

The physical processes governing flow and pollutantdispersion at the neighbourhood scale, a spatial scaleintermediate between the street scale and the city scale, is notwell understood. Furthermore, it is not clear whether a traditional approach using averaged characteristics such as theaerodynamic roughness length is sufficient to predict the concentration field at this scale. To investigate pollutant dispersion in a real urban area, three field experiments were designed within the UK-URGENT programme sponsored by NERC. Theexperiments were performed in the City of Birmingham using a finite duration release of inert, non-toxic and non-depositingtracers, vis. perfluoromethylcyclohexane (PMCH) and perfluoromethylcyclopentane (PMCP). Measurements were taken using air bag samplers placedin an arc at 3.5 km (first experiment) and 1 km (second andthird experiments) from the source; some trap samplers wereplaced outside the main arc in the outskirts of the city. Measurements were analysed in the laboratory using anovel gas-chromatography technique. Data so obtained werecompared with predictions from a simple steady-state modeland a time-dependent model. The concentration-time serieswere very asymmetrical with a sharp rise, a plateau followedby a relatively slow decrease and finally a long-livedplateau above (or possibly very slow decrease to) thebackground level.     

Natural resources dynamics: Exhaustible and renewable resources,and the rate of technical substitution

In this paper we study both exhaustible and renewable resources in an endogenous growth model. In particular, we consider the hypotheses in which the rate of technical substitution (RTS) between those two inputs is or is not equal to one. Moreover, we depart from a basic theoretical framework to account for the negative externality constituted by waste accumulation. Finally, a comparative analysis is made between Pigouvian tax and waste recycling, as an environmental policy to correct market failure represented by refuse accumulation.     

Prediction of syngas quality for two-stage gasification of selected waste feedstocks

This paper compares the syngas produced from methane with the syngas obtained from the gasification, in a two-stage reactor, of various waste feedstocks. The syngas composition and the gasification conditions were simulated using a simple thermodynamic model. The waste feedstocks considered are: landfill gas, waste oil, municipal solid waste (MSW) typical of a low-income country, the same MSW blended with landfill gas, refuse derived fuel (RDF) made from the same MSW, the same RDF blended with waste oil and a MSW typical of a high-income country. Energy content, the sum of H2 and CO gas percentages, and the ratio of H2 to CO are considered as measures of syngas quality. The simulation shows that landfill gas gives the best results in terms of both H2+CO and H2/CO, and that the MSW of low-income countries can be expected to provide inferior syngas on all three quality measures. Co-gasification of the MSW from low-income countries with landfill gas, and the mixture of waste oil with RDF from low-income MSW are considered as options to improve gas quality.     

Geomorphological evolution and environmental reclamation of Fusaro Lagoon (Campania Province, southern Italy)

Analysis of morphological, geological and environmental characteristics of the Fusaro Lagoon has shown the present degraded condition of the lagoon and the perilagoon area. The lagoon developed during the mid-Holocene within a wide marine bay confined between the coastal volcanic structures of Mt. Cuma to the north and Torregaveta to the south in the western part of the Phlegrean Fields. Subsequently, the bay was gradually filled with pyroclastic materials from phlegrean eruptive vents and sediments carried by the rivers Volturno and Clanis, thus, creating an open lagoon. It then evolved into a partially closed lagoon due to the formation of a continuous littoral spit during the late Holocene, probably wider than the present-day one and surrounded by marshlands. Finally, the total closure of the lagoon took place in the Graeco-Roman period, following the stabilization of the dune ridge, and it assumed a shape similar to present-day one only towards the end of the 18th century.Between the Roman period and 1941, three lagoon channels were opened in order to avoid the frequent environmental crises which continue to affect, although for different reasons, this salt-water basin. The basin has been exploited for more than 2000 years not only for mollusc culture and pisciculture, but also for the maceration of hemp and flax. In the 1980s, in order to reduce the effects of the environmental crises, dredging of the lagoon bottom has been carried out, altering the hydrogeological equilibrium and that of the ecosystem. Over the past 30 years, the supply of raw sewage of domestic, agricultural and industrial origin has ensured the presence of a high concentration of pollutants, including heavy metals.On the basis of the data obtained and in order to restore this sensitive transitional environment, eco-compatible interventions are proposed which aim at morphological and hydrologic resettlement, abatement of pollutants on the bottom of the basin, reintroduction of endemic molluscs, together with monitoring the quality of sediments and both sea-lagoon waters and groundwater.     

137Cs contamination in tea and yerba mate in South America

Gamma-ray spectra from more than 50 samples of food products available in stores of Buenos Aires city were measured using a germanium detector. Activity concentrations of 137Cs up to 10 Bq/kg were found in tea and yerba mate manufactured in Apóstoles, Argentina. Further measurements of tea leaves, yerba mate leaves and soils, all coming from a cultivated area in that region, also show the presence of 137Cs contamination. The results suggest that the area was fertilized with a product that originated in a region affected by the fallout from the Chernobyl nuclear plant accident.     

Air bag effectiveness as function of impact speed

An investigation was conducted to estimate the effectiveness of air bags as a function of velocity. The study consisted of three parts: a theoretical idealization, an analysis of National Automotive Sampling System/Crashworthiness Data System (NASS/CDS), and a reanalysis of previously published Fatality Analysis Reporting System (FARS) data. The theoretical analysis looked at idealized risk curves as a function of velocity; assuming that the air bag offers a benefit for both belted and unbelted occupants. Analysis of the NASS/CDS data looked at the effectiveness of air bags as a function of velocity for Maximum Abbreviated Injury Scale (MAIS) 3+ injuries. The reanalysis of the previously published FARS data looked at the effectiveness of the air bag as a function of velocity for fatalities. The theoretical analysis indicates that the air bag effectiveness should be greatest at the low velocities. The field data analysis of both NASS/CDS and FARS were consistent with the theoretical analysis, indicating that air bags are most effective at the lower velocities, below 40 kph (25 mph), for both belted and unbelted occupants. Although it was not possible to estimate a different effect for belted and unbelted for fatalities using FARS, it was possible for MAIS 3+ using NASS/CDS. For unbelted occupants the effectiveness goes to zero or becomes negative above 40 kph (25 mph) for MAIS 3+, and for belted occupants the effectiveness stays positive but with significantly lower magnitude for speeds above 40 kph (25 mph).     

Assessment of older drivers: relationships among on-road errors, medical conditions and test outcome

PROBLEM: It is essential that driver licensing authorities have a valid and reliable system for evaluating older drivers' continuing competency; road tests are usually required as part of such a system. This study sought to find information about the nature of driving errors made during license review tests, and about relationships between error type and test outcome for older drivers. METHOD: Data from licensing authority files from 533 road tests during a 12-month period were analyzed; medical and other referral information was included. Average driver age was 76 years. Performance scores were generated for intersection negotiation, lane changing, low speed manoeuvres, positioning and speed control, safety margin, and car control. RESULTS: Logistic regression analysis showed that test outcome was well predicted by a subset of driving performance scores; adding driver age to the model explained very little variance. Age alone was strongly associated with outcome. Relationships between referral information and test outcome are also reported. IMPACT: Results highlight several factors relevant to the development of more valid and reliable road tests for older drivers.     

Assessment of the leaching of metallic elements in the technology of solidification in aqueous solution

Results are presented of experiments performed to optimize the solidification/stabilization system for metallic elements in aqueous solution. This system involves mixing cement and a solution of metallic elements in a conventional mixer: the paste thus obtained is transferred drop by drop into a recipient filled with an aqueous solution of NaOH at 20% by weight, in which it solidifies immediately. The separate use of chloride solutions of Li+, Cr3+, Pb2+ and Zn2+ makes it possible to obtain granules displaying various levels of compressive strength. Three different inertization matrices were used in the experiments, the first consisting solely of Portland cement, the second of Portland cement and a superplasticizer additive, and the third of Portland cement partially replaced with silica-fume and superplasticizer. The results of the tests performed showed a very low level of leaching into the alkaline solidification solution for Cr3+, the quantity leached being under 2% as against higher levels for the other metallic elements. For all the considered elements, the best results were obtained by using silica-fume in the inertization matrix.