Export efficiency of large projects: The case of aluminium smelters

We draw attention to a number of key factors in the evaluation of major projects, such as smelters, which are highly capital- and energy-intensive as well as export-orientated. The practice of justifying such projects by upvaluing foreign exchange is considered, as is the cost of distortion. Export efficiency is introduced as the key criterion: the efficiency of some recent smelter proposals in Oceania was between 36 and 50 cents in the dollar. A correct power price is essential: hydropower (in contrast with hydroenergy) should be priced as a depletable resource.     

Soil washing: Practical considerations and pitfalls

The use of soil washing to remove petroleum hydrocarbon contamination from the soil matrix is becoming more widely used. When viewed as a volume reduction tool, this technology shows some promise. However, ongoing research and treatability studies indicate that without further treatment, even larger-sized soil fractions (sands and cobbles) may retain hydrocarbon contamination at levels that require further cleaning prior to permanent disposal or reuse. The perception has been that by removing the sand from the soil matrix, thus achieving a 30 percent to 60 percent volume reduction, expensive post-washing treatment or approved disposal of the finer materials (silts and clays) would be cost-effective. There exists evidence to the contrary, however. Hydrocarbon retention after soil washing may be influenced by a number of factors unrelated to particle size. Soil characteristics that may play a role include soil humic acids, metal oxide coatings, geologic origin of the soil particles, and clay type. In this article the authors describe a laboratory study designed to evaluate the “cleanability” of two soils.     

The development of a digital terrain model for the geomorphological engineering of the ‘rolling’ foredune of Terschelling,the Netherlands

The foredunes form an important element of the line of defence which protects the low-lying parts of the Netherlands from the sea. The foredune of the eastern part of the Wadden island of Terschelling has been managed as a ‘rolling’ foredune to maximize the amount of sand available in times of emergency. Following a decision of the Dutch Government to maintain the coastline of 1990, this foredune will now be stabilized. A plan is made to reshape the morphology of the foredune according to a geomorphological design. A simulation model was developed to produce a Digital Terrain Model with the required geometrical information. The transformation which is on the macro-level scale can be achieved within the envisaged medium-scale planning period of five years only by applying earth-moving machinery, placing fences or planting sand-trapping vegetation.     

Schwermetalle in Regenwürmern Baden-Württembergs Teil 2: ?kotoxikologische Bewertung des Bodens

Methoden  

Zur Bewertung der gemessenen Schwermetallbelastungen des Bodens wurden sog. Risiko-Kennlinien für die Metalle Blei, Cadmium, Kupfer, Nickel und Zink entwickelt, die eine einheitliche Charakterisierung von Bodengehalten im Hinblick auf ihre Wirkung auf den Regenwurm sowie auf naturr?umliche Gegebenheiten erm?glichen. Die Mobilit?t der Metalle, die für die biologische Wirkung entscheidender ist als der Gesamtgehalt im Boden, wurde bei der Bewertung berücksichtigt.     

Diving behavior of immature hawksbills (Eretmochelys imbricata) in a Caribbean cliff-wall habitat

Time-depth recorders were attached to immature hawksbills (Eretmochelys imbricata Linnaeus, 1766) residing at the northwestern cliffs of Mona Island, Puerto Rico. Data on diving profiles obtained from four turtles of 32.0 to 53.4 cm straight carapace length revealed strong similarities in behavioral patterns. During daylight hours, turtles were active an average 8.4 h per day, surfacing 3.6% of the time. Length of foraging dives correlated with turtle size, with mean durations ranging from 8.6 to 14.0 min. Foraging dives, with a mean depth of 4.7 m, were associated with feeding on encrusting sponges. At night, turtles were mostly inactive, surfacing 1.8% of the time and with individual mean submergence intervals of between 30.4 and 37.1 min. From the surfacing behavior of turtles making deep and long dives, it is inferred that dives were aerobic, with the turtles making use of oxygen stores in addition to that of the lung.     

Substance flows through the economy and environment of a region

In the tradition of the study of materials flows through society, the Substance Flow Analysis (SFA) method and its software tool SFINX are presented. SFA aims at providing the relevant information for a country’s overall management strategy regarding single substances or coherent groups of substances. Three modelling techniques and their possibilities and limitations are discussed: Bookkeeping, static modelling, and dynamic modelling. The computer program SFINX can be used for varoius purposes: (1) to obtain an overview of stocks and flows of a substance in, out and through a nation’s economy and environment for a specific year, (2) to trace the origins of specific pollution problems, and (3) to estimate the effectiveness of certain abatement measures. Each application has its own requirements with regard to data and modelling.