Untersuchungen zur Nachhaltigkeit der Sanierung von Tributylzinnkontaminiertem Hafensediment durch Landablagerung

To allow ships to pass, most harbours have to be liberated from sedimented material. These sediments often contain high concentrations of tributyltin (TBT), which is used as a biocide in antifouling paints. Thus, the problem of a disposal which is acceptable with respect to a minimum risk for humans and the environment arises. The aim of our project was to assess land deposition as an alternative in dealing with TBT-contaminated harbour sediments. Therefore, we followed the biological degradation of TBT under aerobic and anaerobic conditions at different temperatures using defined laboratory experiments, and got important information about the land deposition, performing field measurements including biomonitoring. The biological degradation of TBT is faster under aerobic conditions and with increasing temperature. The half-lives found show the dependency of the degradation rates on the temperature between 5–55°C. The degradation rate determined for water under the same conditions (just biological degradation, without photolysis) is almost 4 times higher than in sediment. The field studies showed degradation rates of a maximum of 10–15% per year in untreated sediment and 30% per year in restacked sediments. We did not observe any interference of released TBT with ground water or surrounding areas. The TBT uptake in plants was low. Based on our results a multidimensional risk evaluation was performed, concerning the TBT and its degradation products dibutyltin (DBT) and monobutylin (MBT) released from the deposition areas. The land deposition appears to be a sustainable solution for dealing with TBT-contaminated harbour sediments.     

Amniotic fluid calcium concentration in the prenatal diagnosis of cystic fibrosis

Calcium concentrations were measured in supernatant amniotic fluid in order to establish whether they may be used as a marker for cystic fibrosis. No difference in values were found, whether the sample was derived from a normal pregnancy or from a pregnancy which resulted in a baby affected with cystic fibrosis.     

Soil erosion in developing countries: A politicoeconomic explanation

Soil erosion is accelerating in developing countries of Asia, Africa, and Latin America. It has threatened the livelihood of millions of peasants, for agriculture is their economic mainstay. A probe into the forces causing erosion reveals that the elite’s resolve to accumulate ever more wealth and to maintain, consolidate, or expand their sociopolitical power and the necessity of the poor to fulfill their requirements of food, fuelwood, and fodder are the two major factors accelerating soil erosion. Unless the vast masses of poor people are integrated into the national mainstream through the implementation of equitable and redistributive development policies, it is impossible to control the accelerating rate of soil erosion and thus to achieve the objective of sustainable development. In this article, the phenomenon “soil erosion” is studied with the sol e focus on causation through anthropogenic factors.     

The impact of feedback and self-efficacy on performance in training

This field experiment examined the main and interactive effects of self-efficacy and feedback (i.e. the use of feedback versus no feedback) on performance in a speed reading class. Results showed that the provision of feedback was beneficial to the performance of all subjects, however as subject self-efficacy increased, the beneficial effects of feedback to the subject's performance also increased. Subjects who received feedback on their performance experienced significantly greater increases in self-efficacy than subjects who received no feedback. The more positive the performance feedback received, the greater the increase in individual self-efficacy. The implications of these results for training programs are discussed.