Hochwasser 2002

In August 2002, highly contaminated areas in the region of Bitterfeld, e.g. the floodplain of the creek Spittelwasser, as well as the adjacent regions of Jeßnitz and Raguhn, were submerged by the river Mulde. An input of mobilized contaminated sediments in residential areas was the matter of concern. The objective of the present study was to estimate the pollutants load on the basis of chemical and biological data and identify the sources of pollutants. Deposited sludge and flood water samples were assessed on the basis of biological and chemical analyses and in comparison with administrative reference values. The pollution of the investigated sites was rather heterogeneous. At several sites, tolerance limits of the German Klärschlammverordnung or the Bundesbodenschutzverordnung were clearly exceeded, e.g. for Pb, As and HCH. Organic extracts exhibited significant effects in several biotests. This may be relevant with respect to direct particle uptake via ingestion or respiration. Pollution patterns for heavy metals as well as for organic pollutants differed significantly from the pattern found in the Spittelwasser flood plain before the inundation, which is in contrast to the initial hypothesis of a possible transport of contaminated Spittelwasser sediments into residential areas. Interestingly, a correlation of chemical load and the overall biological effect could be shown. From the viewpoint of the precautionary principle, the identification of the compounds exerting toxic effects and of the respective pollutant sources would be desirable.     

Contamination of drinking water resources in the Mekong delta floodplains: arsenic and other trace metals pose serious health risks to population

This study presents a transnational groundwater survey of the 62,000 km(2) Mekong delta floodplain (Southern Vietnam and bordering Cambodia) and assesses human health risks associated with elevated concentrations of dissolved toxic elements. The lower Mekong delta generally features saline groundwater. However, where groundwater salinity is <1 g L(-)(1) Total Dissolved Solids (TDS), the rural population started exploiting shallow groundwater as drinking water in replacement of microbially contaminated surface water. In groundwater used as drinking water, arsenic concentrations ranged from 0.1-1340 microg L(-)(1), with 37% of the studied wells exceeding the WHO guidelines of 10 microg L(-)(1) arsenic. In addition, 50% exceeded the manganese WHO guideline of 0.4 mg L(-)(1), with concentrations being particularly high in Vietnam (range 1.0-34 mg L(-)(1)). Other elements of (minor) concern are Ba, Cd, Ni, Se, Pb and U. Our measurements imply that groundwater contamination is of geogenic origin and caused by natural anoxic conditions in the aquifers. Chronic arsenic poisoning is the most serious health risk for the ~2 million people drinking this groundwater without treatment, followed by malfunction in children's development through excessive manganese uptake. Government agencies, water specialists and scientists must get aware of the serious situation. Mitigation measures are urgently needed to protect the unaware people from such health problems.     

Growth of the queen conch Strombus gigas,with a discussion of the practicality of its mariculture

Data on the growth of the large marine snail Strombus gigas was obtained from specimens collected as veligers in the plankton and reared through metamorphosis, from larger individuals (5.5 cm) reared in a mariculture system, and from field tagrecapture experiments. Using the von Bertalanffy growth equation, I estimate that 1, 2, and 3 year-old juvenile snails are 10.8, 17, and 20.5 cm in maximum shell length, respectively. The snails reach the flaring-lip stage after 3 years and have a mean longevity of another 3 years. Approximately 12% of the total weight of a juvenile snail is marketable meat. Measurements of meat weight, shell length, and total weight are highly correlated with one another, thereby providing reliable means of assessing meat yields from living snails. The mariculture of S. gigas is feasible, but because of the snails' slow rate of growth it may not be economically practical at this time. Perhaps local fisheries in the Caribbean Sea could be reestablished and/or maintained by seeding subtidal algal flats with hatchery-reared juvenile snails.     

II. Aufbau fl?chenrepr?sentativer Probenahmen von Umweltproben zur Schadstoffanalytik am Beispiel der Regenwürmer in landwirtschaftlich genutzten R?umen

Ein sinnvoller Einsatz von Akkumulationsindikatoren erfordert zur Qualit?tssicherung neben den vorhandenen Laborstandards ein anspruchsvolles Probenahmeverfahren, um repr?sentative und reproduzierbate Aussagen über einen Untersuchungsraum treffen zu k?nnen. Am Beispiel der Regenwürmer wird exemplarisch ein Probenahmeverfahren für landwirtschaftliche R?ume entwickelt und vorgeführt. Erste Ergebnisse der in den Wurm- und Kotproben gemessenen polyzyklischen aromatischen Kohlenwasserstoffe, der chlorierten Kohlenwasserstoffe und der Elemente werden dargestellt. Die Schadstoffgehalte der vergleichbaren Wurmproben belegen, da? es die repr?sentative Probenahmestelle in einem Untersuchungsgebiet nicht gibt. Die Heterogenit?t des Untersuchungsraumes kann nur durch eine geschichtete Zufallsstichprobe mit einer ausreichenden Anzahl von Einzelproben erfa?t werden.     

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin or 2,2',4,4',5,5'-hexachlorobiphenyl on vitamin K-dependent blood coagulation in male and female WAG/Rij-rats

Newborns are susceptible to hemorrhages (hemorrhagic disease of the newborn or HDN) due to vitamin K deficiency. Induction of cytochrome P450 in the fetal liver by maternal anticonvulsant therapy such as phenobarbital or phenytoin is considered to be a major cause. An observed increase in late hemorrhagic disease (LHD) in breast fed neonates gave rise to the hypothesis that PCBs and dioxins, P450-inducing contaminants present in human milk, might effect vitamin K-dependent blood coagulation. This hypothesis was studied in rats. Administration of a single oral dose of 0.003, 0.03, 0.3, 3 or 30 nmol 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) per kg bodyweight or 0.75, 4, 20, 100 or 500 micromol 2,2',4,4',5,5'-hexachlorobiphenyl/kg bw (HxCB) to female and male rats resulted in dose-related reductions of the vitamin K-dependent coagulation factor VII. The highest factor VII reduction in female rats was 44%, observed after TCDD exposure. The Lowest Observed Adverse Effect Level (LOAEL) of TCDD on female factor VII levels was 0.3 nmol/kg bw (96 ng/kg). There was a significant inverse correlation between Factor VII levels and induction of hepatic ethoxyresorufin O-deethylating (EROD) activity, reflecting CYP1A1, and total P450 content. HxCB had no effect on female coagulation factors. In contrast, in male rats only exposure to HxCB, which induces mainly CYP2B1 and 2B2, decreased both coagulation factors dramatically up to 88%. The LOAEL of HxCB on factor VII in male rats was 100 micromol/kg bw (36 mg/kg). In general, effects on coagulation factors in male rats exceeded those in females. In addition, sex-dependent differences of TCDD and HxCB were observed on the hepatic vitamin K cycle enzyme activities in female and male rats. Vitamin K-dependent (gamma-glutamyl carboxylase activity was mainly induced in female rats; 2.3-fold in the highest dose group of TCDD. In male rats only vitamin K 2,3-epoxide reductase (KO-reductase) activity was induced 1.7-fold by the highest dose of HxCB. KO-reductase activity in female rats was also increased by TCDD, however, less pronounced than the carboxylase activity. Concluding, the hepatic vitamin K cycle still functions and is not blocked by TCDD or HxCB, thus explaining the observed reduction in factor VII. Finally, the possible role of P450 in vitamin K deficiency is discussed. Based on these results it is suggested to investigate the possible role of PCBs and dioxin-like compounds in LHD in more detail.     

Precipitation and aerosol studies in India

In India, rain water and atmospheric aerosols are observed to bealkaline in nature due to the influence of soil-derivedparticles which are rich in components like Ca and Mg. Thesecomponents increase the neutralization potential of rain waterand have a greater influence at rural site compared to urbansite. However, if there are continuous rains, the concentrationof crustal components becomes lower resulting in lower pH ofrain water. Unlike the characteristics of rain water oncontinent, the pH of rain water has been observed to be acidicin all the events over the Indian Ocean during Pre-campaigns ofIndian Ocean Experiment (INDOEX). The possible reason for acidicrains over Indian Ocean could be the anthropogenic contributionfrom continent transported by NE winds coming towards the oceanduring this period.