Recebido em 22/3/05; aceito em 28/6/05; publicado na web em 20/1/06 SPATIAL AND SEASONAL VARIABILITY OF TRACE-ELEMENT CONCENTRATIONS IN SEDIMENTS FROM THE SANTOS-CUBATÃO ESTUARINE SYSTEM, SÃO PAULO, BRAZIL. Multi-element analyses of sediment samples from the Santos-Cubatão Estuarine System were carried out to investigate the spatial and seasonal variability of trace-element concentrations. The study area contains a rich mangrove ecosystem that is a habitat for tens of thousands of resident and migratory birds, some of them endangered globally. Enrichments of metals in fine-grained surface sediments are, in decreasing order, Hg, Mn, La, Ca, Sr, Cd, Zn, Pb, Ba, Cu, Cr, Fe, Nb, Y, Ni and Ga, relative to pre-industrial background levels. The maximum enrichment ranged from 49 (Hg) to 3.1 (Ga). Mercury concentrations were greater in the Cubatão river than in other sites, while the other elements showed greater concentrations in the Morrão river. Concentrations of Mn were significantly greater in winter and autumn than in summer and spring. However, other elements (e.g. Cd and Pb) showed the opposite, with greater concentrations in summer and spring. This study suggests that seasonal changes in physical and chemical conditions may affect the degree of sediment enrichment and therefore make the assessment of contamination difficult. Consequently, these processes need to be considered when assessing water quality and the potential contamination of biota.

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Numerous diseases are carried and can be transmitted from the African buffalo (Syncerus caffer) to livestock. Therefore, buffaloes may only be moved with a special transport permit. Disease-free buffaloes are in demand amongst private game farmers. Current disease-free animals derive from a small genetic pool and hence there is a special interest in bringing new genetic material into the disease-free populations. Different breeding programs were developed in the past, which allow producing disease-free offspring from an infected herd. In this study epididymal sperm from 16 mature African buffalo bulls were frozen with Triladyl™ and AndroMed ® (both Minitüb, Germany) with or without the addition of bovine seminal plasma. Post-thaw motility, longevity and acrosomal integrity were compared by means of paired two-tailed t-tests. For both cryodiluents the post-thaw motility was mostly higher when no seminal plasma was added: no differences could be seen for the acrosomal integrity. Triladyl™ was superior to AndroMed ® in regards to total post-thaw motility. This study indicates that the use of bovine seminal plasma in a concentration of 10% is detrimental rather than beneficial in regards to the post-thaw motility. Triladyl™ rather than AndroMed ® should be used to freeze buffalo epididymal sperm, since it is superior in terms of post-thaw motility, even though the former, containing egg yolk, is not a defined medium and therefore lacks quality standards and carries a hygiene risk. Cette étude montre que l'utilisation decplasma séminal bovin à la concentration de 10% est plus nuisible que bénéfique en ce qui concerne la motilité post-congélation. Triladyl TM devrait être préféré à Andromed ® pour congeler le sperme épididymal de bison, puisqu'il est meilleur en ce qui concerne la motilité post-congélation, même s'il contient du jaune d'oeuf et n'est pas un milieu défini ( pas de standards de qualité), ce qui sous-entend un risque hygienique. Zusammenfassung