The abundances of rarer trace elements in paddy (rice) soils of Sri Lanka

Concentrations of Ti, Ga, As, Sc, Zr, Sn, Hf, Th, U and Y have been determined for 70 paddy soils from 14 villages, selected throughout Sri Lanka by means of ICP-MS. The mean elemental contents of all paddy soil samples were 6120 Ti, 14.1 Ga, 0.84 As, 7.26 Sc, 129 Zr, 2.27 Sn, 3.64 Hf, 12.71 Th, 1.53 U, and 13.35 Y (all data in microg/g). Paddy soils were classified into groups based on morphology and climate. Higher contents of Th and U were found in the wet zone lowland soils whereas the higher Ti contents were observed in dry zone soils. Arsenic, Zr and Hf contents were comparatively similar in all regions. Factor analysis was used to identify the relationships between the contents of elements.     

Biological dehalogenation and halogenation reactions

A large number of halogenated compounds is produced by chemical synthesis. Some of these compounds are very toxic and cause enormous problems to human health and to the environment. Investigations on the degradation of halocompounds by microorganisms have led to the detection of various dehalogenating enzymes catalyzing the removal of halogen atoms under aerobic and anaerobic conditions involving different mechanisms. On the other hand, more than 3500 halocompounds are known to be produced biologically, some of them in great amounts. Until 1997, only haloperoxidases were thought to be responsible for incorporation of halogen atoms into organic compounds. However, recent investigations into the biosynthesis of halogenated metabolites by bacteria have shown that a novel type of halogenating enzymes, FADH(2)-dependent halogenases, are involved in biosyntheses of halogenated metabolites. In every gene cluster coding for the biosynthesis of a halogenated metabolite, isolated so far, one or several genes for FADH(2)-dependent halogenases have been identified.     

Long-term sampling method for polychlorinated dibenzofurans (PCDFs) and dibenzo(p)dioxins (PCDDs) in flue gas of combustion facilities

A long-term sampling method for PCDF/D in emissions from combustion facilities is presented. The sampling of PCDF/D was performed over a four week period. The results are compared to results of four one-week measurements.     

Incomplete International Cooperation to Reduce CO2 Emissions: The Case of Price Discrimination

This paper analyzes the effect of introducing a fuel tax in some countries, but not all, when the world fuel market is monopolistic. Based on the observation that price discrimination becomes possible in these circumstances, it is shown that the fuel price in countries not levying the tax may increase, in contrast to common views.     

Agenda 21 Realisierungsmöglichkeiten an Hochschulen

Chapter 36 from the Agenda 21 which was held at the Conference for the Environment and Development in 1992 provides suggestions for ?promoting education, public awareness and training“ and important contributions for continuing developments in the universities. The goals which have been mentioned here can only be realized on a long-term basis. A work group at the University in Furtwangen has concentrated on the adaptation of this theme since 1991. After five years, it is now possible to draw a provisional balance: The disciplines of the environment, technology, law and ecology are bound together through a reformed course of studies in the field of process engineering. The certification based upon the EC eco-auditing ordinance offers new prospects for increasing the integration of environmental aspects on a broad basis into the routine university life. The establishment of a regional environmental center provides a possibility for the exchange of knowledge as a joint venture.     

Verglaste Filterstäube aus Müllverbrennungsanlagen

Solid waste residues from municipal solid waste incinerator flue gas cleaning systems basically consists of Al, Ca-silicates and metal oxides. At lower concentrations, environmentally harmful compounds such as alkali halide salts, heavy metals and traces of organic pollutants, e.g. PCDD, PCDF and PCB, are also present. For the reuse of the valuable materials (Al, Ca and metal oxides), an effective treatment technique for destroying the organic contaminants and separating the anorganic toxins from the non-toxic components has to be applied, which can only be achieved through thermal processing. Detailed investigations on vitrified electrostatic precipitator ash from municipal solid waste incinerator plants have shown promising results in regard to the mass balances, the chemical composition and the quality of the glass phase obtained.     

Nestling size rank in the little egret (Egretta garzetta) influences subsequent breeding success of offspring

Few studies have investigated the long-term fitness consequences of nestling size hierarchies in altricial birds. In this study, we investigated whether or not the size rank order of siblings influences subsequent breeding success in the little egret, Egretta garzetta. From a marking program allowing individual recognition of wild birds, we obtained data on the breeding success of 56 pairs comprising individuals for which the size rank order was known. The breeding success in these pairs was positively influenced by the age of the marked bird but negatively affected by the laying date of the pair and the size rank order of the marked individual. There was also a significant difference between breeding colonies. We suggest two main hypotheses for a link between size rank order of individuals and their breeding success and we discuss our results in relation to current hypotheses on the adaptive value of hatching asynchrony. Received: 10 August 1998 / Accepted after revision: 13 December 1998