Environmental hazard — Assessment of chemicals and products

Part III: The Limits to Single Compound Assessment The principles and basic assumptions of single compound assessment are briefly reviewed. Limitations to this approach are shown, especially with regard to complex mixtures of similar substances, substitution products, and complicated (final) products containing chemicals and materials produced by the chemical industry. A new thinking in product lines and life cycles is emerging, leading to new assessment methods. In some cases, substitution has not improved the environmental performance of products, since very similar chemicals were used as substitutes.     

Disruption of retinoid transport, metabolism and signaling by environmental pollutants

Although the assessment of circulatory levels of retinoids has become a widely used biomarker of exposure to environmental pollutants, the adverse effects caused by imbalance of the retinoid metabolism and signaling in wildlife are not known in detail. Retinoids play an important role in controlling such vital processes as morphogenesis, development, reproduction or apoptosis. Unlike other signaling molecules, retinoids are not strictly endogenous but they are derived from dietary sources of vitamin A or its precursors and thus they are sometimes referred to as 'dietary' hormones. Some environmental pollutants that affect embryogenesis, immunity or epithelial functions were also shown to interfere with retinoid metabolism and signaling in animals. This suggests that at least some of their toxic effects may be related to interaction with the retinoid metabolism, transport or signal transduction. This review summarizes in vivo and in vitro studies on interaction of environmental complex samples, pesticides, polychlorinated dioxins, polychlorinated biphenyls, polycyclic aromatic compounds and other organic pollutants with physiology of retinoids. It sums up contemporary knowledge about levels of interaction and mechanisms of action of the environmental contaminants.     

Spontaneous vegetation succession at different central European mining sites: a comparison across seres

We performed detrended correspondence analysis (DCA) ordination to compare seven successional seres running in stone quarries, coal mining spoil heaps, sand and gravel pits, and extracted peatlands in the Czech Republic in central Europe. In total, we obtained 1,187 vegetation samples containing 705 species. These represent various successional stages aged from 1 to 100 years. The successional seres studied were more similar in their species composition in the initial stages, in which synathropic species prevailed, than in later successional stages. This vegetation differentiation was determined especially by local moisture conditions. In most cases, succession led to a woodland, which usually established after approximately 20 years. In very dry or wet places, by contrast, where woody species were limited, often highly valuable, open vegetation developed. Except in the peatlands, the total number of species and the number of target species increased during succession. Participation of invasive aliens was mostly unimportant. Spontaneous vegetation succession generally appears to be an ecologically suitable and cheap way of ecosystem restoration of heavily disturbed sites. It should, therefore, be preferred over technical reclamation.     

Umweltvertr?glichkeitsprüfung (UVP) für Pl?ne und Programme

Zusammenfassung  Der Beitrag besch?ftigt sich mit der bald notwendigen Einführung einer Umweltvertr?glichkeitsprüfung für Pl?ne und Programme in das deutsche Umwelt-und Planungsrecht. Zun?chst werden Ziel und Zweck sowie europ?ischer Hintergrund dieses Umweltinstruments erl?utert. Sodann geht es um das Recht der Bauleitplanung. Es werden überlegungen angestellt, wie man den europ?ischen Anforderungen in diesem Bereich gerecht werden k?nnte. Siehe UWSF12 (6) 350 (2000) Schlagw?rter: deutsches Umwelt- und Planungsrecht; Pl?ne; Plan-UVP-Richtlinie; Programme; SEIA; Strategic Environmental Assessment (SEIA); Umweltvertraglichkeitsprüfung (UVP); UVP