Kenntnisdefizite bei Stoffeigenschaften und ihre Folgen

The data situation to chemical substances is unsatisfactory— in spite of in part considerable efforts in the last decades. One knows still very little on the subject of the dangerous characteristics of chemical substances. The consequences of this ignorance have primarily the employees to carry. They get sick due to a dealing with substances whose characteristics were not completely enlightened. But as well the enterprises have to suffer under it, after all, lose her experienced staff member and have to pay the costs about the Berufsgenossenschaften for these knowledge deficits. In the EU, the future European chemical policy is therefore discussed. The contribution explains the range of the sicknesses through dealing with substances with unknown characteristics.     

Schwermetallbelastung von Dreissena polymorpha in Donau und Drau und ihre Bedeutung als Bioindikator

Goal and Scope

This study was undertaken to investigate the differences in heavy metal burden between the organisms and environmental compartments and to evaluate the role of Dreissena polymorpha as a bioindicator organism.

Methods

The concentrations of zinc, copper, cadmium and lead in whole soft body and selected tissues of D. polymorpha at two river habitats in Austria were examined using atomic absorption spectroscopy (AAS). Concentrations in organisms were compared to those in sediment and water.

Results and Conclusion

Zebra mussels of the river Drau showed generally higher heavy metal concentrations as compared to mussels of the river Danube and contained elevated zinc and cadmium levels as compared to metal concentrations found in soft tissues of zebra mussels from uncontaminated sites in Germany and The Netherlands. The essential metals zinc and copper were mainly accumulated in gills, foot and byssal gland tissue of the mussel, in contrast to the non-essential metals cadmium and lead which were found predominantly in the midgut gland. The heavy metal concentrations in both, sediments and mussel tissue, were higher than in water samples. There was no correlation between the concentrations in water and in the organisms except for zinc. In contrast, correlations were found between concentrations in sediments and mussel soft tissue.

Recommendation and Perspective

Further investigations should include the examination of sediments and consider the mechanism of food uptake to assess the role of D. polymorpha as a bioindicator organism.     

Die Bedeckungsreaktion von Seeigeln. Neue Versuche und Deutungen

The conditions under which covering (“decorating”, “masking”) takes place have been studied in the sea urchins Paracentrotus lividus, Psammechinus miliaris and 2 other species. Covering occurs equally in darkness or light. It requires suitable objects and locomotion or searching activity of the tube feet. The covering reaction which may follow chemical, mechanical or optical stimuli may be purely the result of an increase in locomotory or general activity. Initial selection of different covering objects depends on the tube feet reflexes; size, form and weight of the object are important. Whether an object is accepted or not, depends on its surface and structure, the amount of water movement and the general activity level of the sea urchin. Transparency and colour of an object do not appear to be important. It is suggested that the covering process can be explained in terms of local tube feet and spine reflexes. The loading-up of objects may be understood as “relative walking”: the same reflexes which move the urchin on stable ground, draw loose particles towards the animal and then upwards.     

Die Symbiose zwischen dem acoelen Turbellar Convoluta convoluta und Diatomeen der Gattung Licmophora

Newly hatched Convoluta convoluta (Abildgaard) are always without symbionts. They acquire the organisms, which later become their zooxanthellae, with their food. In the field this is an automatic process, since C. convoluta without zooxanthellae have never been reported. The main diet of the young C. convoluta are various diatoms and spores of red algae. The symbionts of C. convoluta originate from diatoms of the genus Licmophora. This fact has been established in young specimens both in the sea and in laboratory cultures. Freshly hatched C. convoluta were fed with Licmophora hyalina (Kütz.) Grunow and Licmophora communis (Heib.) Grunow. Licmophora cells, capable of infesting C. convoluta, slip out of their silica shells and later occur between the cells of the peripherical parenchyma. High population densities of zooxanthellae, produced by numerous divisions of the naked diatom cells, are only possible in the host's parenchyma if the young C. convoluta continue to feed. Adult turbellarians with a high population density of symbionts feed less than the young, but never stop food uptake completely. Artificial infestation with symbionts can be brought about by making sub-adult turbellarians take up isolated zooxanthellae as food. Symbionts outside their host neither propagate nor regenerate silica shells in the culture medium employed. The obligatory nature of the mutual interrelation between C. convoluta and zooxanthellae has been proved by the great difficulties in rearing symbiontless individuals, and by starvation experiments both with sub-adults containing only a few symbionts and adults coloured brownish due to a compact layer of zooxanthellae.     

Physiologische Anpassungen eines marinen insekts. II. Die Eigenschaften von schwimmenden und absinkenden Eigelegen

The gelatinous egg-masses of Clunio marinus (Diptera; Chironomidae) consist of a tube of jelly containing up to 175 eggs. The swimming egg-mass of the Atlantic populations (Race A) and the sinking egg-mass of the Baltic populations (Race B) have a higher density than the sea water, on which the female spawns; salinity is not important to the swimming or sinking of the egg-masses. Density and sinking velocity of gelatinous egg-masses from Atlantic midges are significantly higher than those from Baltic midges if the eggs are laid on water of the same salinity. The density of the eggs and the quantitative relation of eggs to jelly are the same in both races. The jelly of the egg-masses from the Baltic Sea race swells more than that from the Atlantic Sea race (increase of volume by absorption of water = 3-fold and 2.4-fold, respectively). During swelling the jelly alters from a trough-like shape into a tube-like from which closes around the eggs. If the surface tension of the spawning medium is lowered by use of detergents, the A-spawn will sink. A- and B-spawns occupy different positions at an oil-water interface. Interference contrast microscopy revealed that the A-jelly forms a well-defined outer line in relationship to the surrounding aqueous medium; this line is missing in the B-jelly. The morphological fine surface structures, as seen by the scanning electron microscope, do not explain the different properties of the A- and B-spawn. Extracts and hydrolysates of jelly material were separated by thin-layer chromatography. The results indicate that the spawn jelly of C. marinus consists of a polysaccharide-protein-complex, similar to the jellies of other invertebrates. It is rather probable that the chemical structure or the components of the jellies from A- and B-populations are not exactly the same; this would explain the different properties described. The ecological significance of swimming and sinking gelatinous egg-masses and the taxonomical position of both midge populations are discussed.     

Die verbreitung der kaltwasser- und der warmwasserfauna der Appendicularien im nördlichen Nordatlantischen Ozean im Spätwinter und Spätsommer 1958

The Appendicularia caught in vertical hauls during the cruises of R.V. “Anton Dohrn” and R.V. “Gauß” in the northern North Atlantic Ocean, in late winter and late summer of the International Geophysical Year (I.G.Y.), 1958, were investigated. In addition, material caught during spring, 1955 by R.V. “Anton Dohrn” was used (Figs. 1 and 2; Tables 1 and 2). Seasonal differences are revealed in the appendicularian fauna in the open ocean between 40° and 65° northern latitude. Among the species caught (Table 2) in 1955, northwest of the Hebrides, Pelagopleura australis Bückmann 1923 (Fig. 3) is of special interest. This species has hitherto only been found in antarctic and southern waters; it is, however, possible that Sinistroffia scripsii Tokioka 1957 is a synonym. In the same place, a new form of Fritillaria venusta Lohmann was found, which is described as F. venusta f. replicata n.f. (Fig. 4). The hitherto known form should be named F. venusta f. bicornis. In Figs. 5 to 7, the species dominating in single catches are indicated by symbols. A borderline between the areas of cold-water and warm-water forms can be drawn. This line is located farther to the North in late summer than in late winter. In the eastern part of the area investigated, the difference amounts to 5° latitude. Warm-water species prevail over cold-water species or appear in equal numbers in both seasons in places where water with temperatures above 11°C is found within the upper 100 m (Figs. 8 and 9). It is, however, known that Oikopleura dioica thrives also at temperatures of 10°C and below; this was also found in the spring of 1955. Cold-water species exhibited higher frequencies as well as abundances, in the late summer than in the late winter of 1958. This fact is chiefly due to an increase in individual numbers of the most important boreal species, Oikopleura labradoriensis, but also of the arctic O. vanhoeffeni and the boreal Fritillaria borealis typica. Relative to O. labradoriensis, the population of F. borealis typica decreases in late summer. During spring 1955, both species exceeded the 1958 values by far. This is considered to be the result of annual, rather than seasonal, differences. The composition of the warm water fauna (Tables 4 and 5) reveals considerable seasonal differences. In late winter, O. longicauda is the most abundant species; it prevails in almost all warm-water catches. In late summer, it is outweighed by O. dioica and O. fusiformis in the total catch, by O. dioica in many single catches in the whole warm-water area, by O. fusiformis in its north eastern part in a few very rich catches, together with Fritillaria pellucida. For size comparison of the individnals, standard trunk length could not be used because of the generally bad state of preservation. In Oikopleura, the lengths of the left stomach lobe were measured instead. It is, however, to be taken into account that the regression of body length to the stomach length (left side) is different at different stages of maturity. In ripening and ripe individuals, body length increases at a higher rate because of growths in length of the gonads. The regressions were calculated for 3 maturity stages (A, B, C; Figs. 10, 12 and 14) of O. labradoriensis and O. vanhoeffeni. In O. longicauda, the specimens were distinctly smaller during late summer, and the proportion of juveniles (stage A) was much higher (Fig. 11). Possibly, this is caused by a reproduction rate still reduced during late winter, but increasing later in the year. O. labradoriensis shows similar, though less pronounced, differences in the proportion of maturity stages, and no significant differences in size composition (Fig. 13). The 1955 material contains a much higher proportion of mature individuals than either cruise of 1958. Similar conditions as in O. longicauda cannot, therefore, be assumed to be involved in regard to O. labradoriensis, at least not at present. There were more mature O. vanhoeffeni individuals present in spring 1955, but they were much smaller than during late summer 1958. No explanation for this observation can, at present, be offered.     

Die verbreitung der uferwanzen (Heteroptera: Saldidae) im brackigen und marinen litoral der nordamerikanischen pazifikküste

Shore bugs (Heteroptera: Saldidae) were collected during summer 1973 along the Pacific Coast of North America between the arctic and the subtropical regions. The field studies were aimed at determining the species-specific upper and lower limits of distribution in the littoral, and the distribution range of these species in estuaries. The saldids inhabiting the littoral zones can be divided into two groups: those species which live mainly along the coast (coastal species), and those which live mainly inland (inland species). Species found in the supralittoral occur at inland localities as well, and thus can either tolerate limnetic-oligohaline conditions (Salda littoralis, S. provancheri, Saldula coxalis) or are confined to habitats along salt lakes (Pentacora signoreti). Inhabitants of the eulittoral can either occur in the supralittoral and inland localities as well and are holeuryhaline (Saldula palustris, S. pallipes), or have disconnected inland populations (S. nigrita), or they live exclusively in the intertidal zones. In the subarctic, coastal species are distributed from the intertidal zones to inland limnetic habitats. The increasing aridity of southern climatic zones may act as a limiting factor confining the distribution of coastal species to the coast. On the other hand, the distribution of inland species may be influenced by competition with the coastal forms.

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Mit dankenswerter Unterstützung der Deutschen Forschungsgemeinschaft.     

Die Miesmuschel Mytilus edulis als Indikator für die Bleikonzentration in Weserästuar und in der Deutschen Bucht

Common mussels were collected at 13 stations of the Weser Estuary and the German Bight in 3 size catagories: 14 to 16 mm, 21 to 23 mm, 35 to 40 mm shell length. Equal numbers of the 3 groups from each station were analyzed separately for lead concentration by flameless atomic-absorption spectrophotometry. The lead concentration of the soft parts decreases from 6.4 μg/g dry weight 15 km northwest of Bremerhaven to 1.9 μg/g at Helgoland. At the same station, the concentration in small musels is significantly higher than in larger mussels. The lead concentration is exceptionally high in the kidney, quite high in the intestine (with the digestive glands) and in the adductor muscle, and rather low in the foot, gills, and mantle with gonads. Unpublished results of my laboratory experiments reveal that mussels directly reflect the actual lead concentration of their environment. The observed gradient in lead contents of M. edulis in the Weser Estuary can thus be explained by the dilution of the highly lead-polluted river water by the sea water of the German Bight. With this physiological property, M. elulis is, therefore, highly suitable as an indicator organism for lead, and possibly other heavy metal pollutants.     

Die von REACH ausgelösten Veränderungen im Hinblick auf die neu definierte Verantwortung von Herstellern und industriellen Nutzern

The changes initiated by REACH towards the newly defined responsibility of producers and industrial users are presented. The data acquisition for ‘old chemicals’, and hereby the improvement of risk assessment, will start in 2007, though will take more than ten years. The data material shows gaps in the area of occupational health and safety. The protection of consumers from substances in products remains insufficient. Nevertheless, for chemicals policy, REACH is a big step forward.