Abschätzung der Quecksilberexposition

A site contaminated by mercury serves as an example for evaluating the environmental medicine aspects of mercury emissions on individuals living in the surroundings. Based on defined, conventional scenarios, estimations of internal exposure were made for seven different age groups and with regard to such contact media as soil, air and food. Using human monitoring methods, an attempt was made to compare the epidemiological results. The site-specific and pathway-specific estimation of exposure is based on a multitude of various samples as well as on measurements of concentrations in the compartments relevant for intake. As based upon rigid guideline values, both these calculations and the epidemiological investigations reveal a slight increase in the mercury exposure.     

Plant and Soil System Responses to Ozone After 3 Years in a Lysimeter Study with Juvenile Beech (Fagus sylvatica L.)

A lysimeter study was performed to monitor effects of elevated ozone on juvenile trees of Fagus sylvatica L. as well as on the plant–soil system. During a fumigation period over almost three growing seasons, parameters related to plant growth, phenological development and physiology as well as soil functions were studied. The data analyses identified elevated ozone to delay leaf phenology at early and to accelerate it at late developmental stages, to reduce growth, some leaf nutrients (Ca, K) as well as some soluble phenolics (hydroxycinnamic acid derivatives, total flavonol glycosides). No or very weak ozone effects were found in mobile carbon pools of leaves (starch, sucrose), and other phenolic compounds (flavans). Altered gene expression related to stress and carbon cycling corresponded well with findings from leaf phenology and chemical composition analyses indicating earlier senescence and oxidative stress in leaves under elevated ozone. Conversely in the soil system, no effects of ozone were detected on soil enzyme activities, rates of litter degradation and lysimeter water balances. Despite the fact that the three reported years 2003–2005 were climatically very contrasting including a hot and dry as well as an extremely wet summer, and also mild as well as cold winters, the influence of ozone on a number of plant parameters is remarkably consistent, further underlining the phytotoxic potential of elevated tropospheric ozone levels.     

Acetate uptake from ambient water by the free-living marine nematodeAdoncholaimus thalassophygas

Nematodes belonging to the family Oncholaimidae are known to aggregate at sites of organic pollution. The oncholaimidAdoncholaimus thalassophygas (De Man, 1876), collected from the Weser Estuary, FRG, in 1989, has the capability to take up acetate at naturally occurring concentrations. Under almost axenic conditions, ca 2.3 to 3.0 ng sodium acetate was taken-up per worm within 24 h, when an ambient concentration of 0.33 mmol was offered. The concentration factor was ca 8.5 to 11.1. The results suggest that a highly motile oxybiotic nematode may benefit from the fermentation products of anoxic habitats.Contribution No. 251 of the Alfred-Wegener-Institute for Polar and Marine Research