Emmy Magerl's visiting-card

<div><p>The antibacterial properties of nanosilver have led to a versatile application spectrum including medical purposes and personal care products. However, the increasing use of nanosilver has raised concerns about its environmental impacts. Long-term exposure studies with aquatic invertebrates are essential to assess possible adverse effects on aquatic ecosystems. In the present study, acute (48 h), chronic (21 d) and long-term effects of nanosilver (primary size 15 nm) on five successive generations of three <i>Daphnia</i> species (<i>D. magna</i>, <i>D. pulex</i>, and <i>D. galeata</i>) were investigated. Acute EC₅₀ values of nanosilver were 121 µg Ag L⁻¹ for <i>D. magna</i> being the least sensitive species and 8.95 and 13.9 µg Ag L⁻¹ for <i>D. pulex</i> and <i>D. galeata</i>, respectively. Chronic exposure provided EC₁₀ values of 0.92 µg Ag L⁻¹ for <i>D. magna</i> showing the most sensitive chronic reaction and 2.25 and 3.45 µg Ag L⁻¹ for <i>D. pulex</i> and <i>D. galeata</i>, respectively. Comparative exposure to AgNO₃ revealed a generally higher toxicity of the soluble form of silver. The multi-generation experiments resulted in effects on the population level for all tested species. Exposure of <i>D. magna</i> indicated an increased toxicity of nanosilver in the fifth generation of animals exposed to 10 µg Ag L⁻¹. Neonates from pre-exposed parental daphnids did not completely recover when transferred into clean water. Exposure of <i>D. pulex</i> and <i>D. galeata</i> revealed not only increasing toxicity in some generations, but also greater tolerance to nanosilver. This study contributes to the assessment of the risk potential of nanosilver on aquatic ecosystems. It shows that effects of nanosilver vary within one genus and change with exposure duration. Therefore, long-term studies considering different aquatic species are needed to better understand the possible effects of nanosilver on aquatic ecosystems.</p></div

A comparison of the short-term toxicity of cadmium to indigenous and alien gammarid species

Amphipods play an important role in many aquatic ecosystems and are commonly used in ecotoxicology and ecosystem health assessment. Several alien gammarids have been introduced in many regions of the world during the last decades. In this study, we investigated if differences in cadmium sensitivity occurred between (1) different species belonging to the family Gammaridae and (2) different populations of the same species originating from a polluted or a non-polluted site. The acute cadmium toxicity to two indigenous (Gammarus pulex and Gammarus fossarum) and four alien (Dikerogammarus villosus, Echinogammarus berilloni, Gammarus roeseli and Gammarus tigrinus) gammarids occurring in Belgium was tested. Significant differences (P < 0.05) in median lethal concentrations (LC50) were found between the different species, with 72 h-LC50s ranging from 6.3 to 268 μg/l and 96 h-LC50s from 4.7 to 88.9 μg/l. No clear trend in Cd sensitivity was found when comparing indigenous and alien gammarids. D. villosus, an alien invasive species, was the most sensitive to Cd toxicity and E. berilloni, another alien species, the least sensitive. In addition, larger Gammarid species were more sensitive to Cd toxicity than smaller ones. No significant differences were found between populations of the same species originating from metal polluted sites or non-polluted sites. Overall, our results showed that considerable differences in Cd sensitivity exist between gammarid species, which should be taken into consideration in environmental risk assessment and water quality standard setting. Finally, our data suggest that alien gammarids would not have an advantage over indigenous gammarids in Cd contaminated environments