Environmental interactions of Sulphlex pavement

Sulphlex, a mixture of elemental sulfur and plasticizers, has been considered for use as an asphalt substitute in road construction. Because this material contains substantial quantities of elemental sulfur, it is a potential substrate for growth of sulfur-oxidising bacteria. Experiments, performed to determine the susceptibility of Sulphlex in Sulphlex-containing media to degradation by Thiobacillus thiooxidans, resulted in breakdown of the Sulphlex material and concomitant production of acid. In concurrent studies, plants were grown in Sulphlex-amended soils. These plants exhibited higher sulfur content and reduced productivity as compared with plants grown in unamended soils, indicating that Sulphlex was being broken down in the soil and that the breakdown products were apparently having a detrimental effect on plant productivity. These experiments indicate that naturally occurring sulfur-oxidising bacteria have the potential to break down Sulphlex paving material, resulting in adverse effects on both the structural integrity of the pavement and the local environment.     

Prenatal ultrasonographic diagnosis of radial-ray reduction malformations

Radial-ray reduction malformations (RRRMs) may occur isolated or in association with other anomalies. The data of seven fetuses born with RRRMs were collected. Six fetuses had associated lethal abnormalities of the central nervous system, urogenital system, and/or heart, detected by ultrasound. In five cases, it was possible to establish the precise diagnosis, enabling an informed prognosis and subsequent genetic counselling. The diagnoses were: Edwards syndrome (n=3), VACTERL association (n=1), and Poland-Moebius-like complex (n= 1). In two cases, a complete diagnosis was not possible because of inadequate evaluation of these fetuses before and/or after birth. A proposal is given for the diagnostic approach for infants with RRRMs detected in the antenatal period by means of ultrasonography.     

Method verification for determination of tetrachlorodibenzodioxin in soil

Methods for the determination of tetrachlorodibenzodioxin (TCDD) in surface and subsurface soil have been verified by spiking experiments conducted at a nominal level of twice the limit of detection. The methods involve Soxhlet extraction, silica and alumina clean-up and analysis by high resolution gas chromatography/ high resolution mass spectrometry. Mass Spectrometry done under profile data control is described. The precision (accuracy) found for surface and subsurface soils were 10.8% (85%) and 10.8% (95%) respectively. Application of the surface soil procedure is illustrated by analysis of soils from the Northeast United States.     

Assessment of the sustainability of technology by means of a thermodynamically based life cycle analysis

Life cycle analysis is one of the tools in the assessment of the sustainability of technological options. It takes into account all effects on the ecosystem and the population which may endanger the possibilities of current and future generations. However, the main bottleneck in current LCA methodologies is the balancing of different effects, being all quantified on different scales. In this work, a methodology is proposed, which allows one to quantify different effects of the production, consumption and disposal of goods, and services on a single scale. The basis of the methodology is the second law of thermodynamics. All production, consumption and disposal processes affecting the ecosystem and the population, are quantified in terms of loss of exergy. The exergy content of a material is the maximum amount of energy which can be transformed into work at given environmental conditions. Next to the elaboration of the methodology, the new approach is illustrated by examples of the production of synthetic organic polymers, inorganic building insulation materials and different waste gas treatment options.     

Investigations of nitrogen fluxes and pools on a limestone site in the Alps

In the North Tyrolean Limestone Alps a site was investigated over a four-year period (1998–2001) in order to assess the nitrogen saturation status, the nitrogen budget (quantification of the net uptake of nitrogen by the canopy and of the nitrogen mineralization, nitrogen uptake from roots and N₂O emission rates, proof of the origin of nitrate in the soil water with stable isotope analyses), and the effects of the actual nitrogen input on ground water quality. The main goals were to quantify the nitrogen input rate, the nitrogen pools in above-ground and below-ground compartments, nitrogen turnover processes in the soil as well as the output into the groundwater and into the atmosphere. The findings are based on continuous and discontinuous field measurements as well as on model results.While nitrogen input exceeded the Critical Loads of the WHO (1995), nitrogen deficiency and nutrient imbalances were verified by needle analyses. The atmospheric input of inorganic nitrogen was higher than the nitrogen output in 50 cm soil depth. A tracer experiment with¹⁵N helped to prove that not more than half of the applied nitrate could be discharged. This allows the conclusion that nitrogen is stored in the system and that the site cannot yet be said to be saturated with nitrogen. The same result was also obtained by modelling. In addition, it was proved that the nitrogen discharge did not stem from deposition but from processes within the system.     

印度洋-太平洋海洋生态系统的占有:活礁鱼食品贸易的实例研究

我们对珊瑚礁渔业,特别是活礁鱼食品贸易(FT)的生态足迹的分析表明,许多国家目前的消费量超过了估计的可持续的人均全球、地区及地方珊瑚礁生产水平.香港通过其FT需求占有了东南亚年礁鱼生产量135 260～286 560t的25%,超过地区生物生产力8.3倍;礁鱼渔业需求超过印度洋-太平洋和东南亚地区可持续产量2.5～6倍.相比之下,大多数太平洋岛屿靠本身的礁渔业手段维持生计,当地的需求小于大洋洲整个能力的20%.FT每年需要多达40%东南亚的估计礁鱼产量以及几乎所有其估计的(鱼旨)科鱼产量.我们的研究分析结果强调了FT的不可持续性以及对印度洋-太平洋珊瑚礁渔业加以区域管理和保护的迫切必要性.     

Aus den frühen Tagen der Makromolekularen Chemie

Most branches of science pass through a “pioneering period” where different concepts and approaches create, for a while, a turbulent atmosphere until, on the basis of new experimental evidence, clear and durable principles emerge, which lead to a broad and continuous growth of basic understanding and practical application. The author of this article recalls how, temporarily, conflicting ideas created confusion in the chemistry and technology of giant molecules before these disciplines developed into what they are now: indispensable contributors to the comfort, safety and expansion of our society from medicine to astronautics.     

Modeling Land-Use Change in a Decision-Support System for Coastal-Zone Management

RaMCo is a prototype version of a decision-support system for coastal-zone management. The model is based on the findings of a multidisiciplinary research program, conducted in Southwest Sulawesi, Indonesia. Different management strategies can be compared on the basis of the short- and long-term consequences. Land-use change has been included in RaMCo in view of the impacts of land-based human activities on the marine environment. The key aspect of the model is a combination of the temporal dynamics of land-use change on the regional (macro-level) scale and spatial dynamics on the local (micro-level) scale. Constrained cellular automata are used to integrate both scale levels. The state changes of the cells depend on the consistency with the macro-scale model, local geographical conditions, and interaction with neighboring cells. In this paper, we discuss the underlying theoretical assumptions of the macro-scale and micro-scale models, some characteristic results for land-use change in the study area, and the validation problem.     

Benzene, toluene, ethyl benzene and xylenes in ambient air and Pinus sylvestris L. needles: a comparative study between Belgium, Hungary and Latvia

Concentrations of benzene, toluene, ethyl benzene and xylenes (BTEX) in ambient air and in 1 yr old Pinus sylvestris pine needles were monitored along a busy road, petrol station and rural area of Belgium, Hungary and Latvia in a 1 yr period. To test P. sylvestris as a possible biomonitor for the BTEX concentrations, samples were taken in the four seasons. As the distribution of data was not normal, the level of pollution on different sites and seasons was compared and evaluated by non-parametric tests. The measured air concentrations did not differ significantly from one season to another throughout the year. There were, however, differences between sampling places. The C₂-alkylbenzene and toluene concentrations in the needles were similar in the autumn/winter and spring/summer periods but a significant decrease in their concentration was observed in every place between winter and spring. This effect was less obvious for toluene.