Biological Activity in a Heavily Organohalogen-Contaminated River Sediment (8 pp)

Background, Aims and Scope Sediments of the Spittelwasser creek are highly polluted with organic compounds and heavy metals due to the discharge of untreated waste waters from the industrial region of Bitterfeld-Wolfen, Germany over the course of more than one century. However, relatively few data have been published about the chloroorganic contamination of the sediment. This paper reports on the content of different (chloro)organic compounds with special emphasis on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), and chlorobenzenes. Existing concepts for the remediation of Spittelwasser sediment include the investigation of natural attenuation processes, which largely depend on the presence of an intact microbial food web. In order to gain more insight in terms of biological activity, we analyzed the capacity of sediment microflora to degrade organic matter by measuring the activities of extracellular hydrolytic enzymes involved in the biogeochemical cycling of carbon, nitrogen, phosphorus and sulfur. Furthermore, the detection of physiologically active bacteria in the sediment, particularly of those known for their capability to reductively dehalogenate organochlorine compounds, illustrates the potential for intrinsic bioremediation processes. Methods PCDD/F and chlorobenzenes were analyzed by gas chromatography(GC)/mass spectrometry and GC/flame ionization detection, respectively. The activities of hydrolytic enzymes were determined from freshly sampled sediment layers using 4-methylumbelliferyl (MUF) or 7-amino-4-methylcoumarin-conjugated model compounds and kinetic fluorescence measurements. Physiologically active bacteria from different sediment layers were microscopically visualized by fluorescence in situ hybridization (FISH). Specific bacteria were identified by 16S rRNA gene amplification and sequencing. Results and Discussion The PCDD/F congener profile was dominated by dibenzofurans. In addition, the presence of specific tetra and pentachlorinated dibenzofurans supported the assumption that extensive magnesium production was one possible source for the high contamination. A range of other chloroorganic compounds, including several isomers of chlorobenzenes, hexachlorocyclohexane and 1,1,1-trichloro-2,2-bis (p-chloro-phenyl)ethane (DDT), was present in the sediment. Activities of extracellular hydrolytic enzymes showed a strong decrease in those sediment layers that were characterized by high contents of absorbable organic halogen (AOX), indicating disturbed organic matter decay. Interestingly, an abnormal increase of cellulolytic enzyme activities below the organochlorine-rich layers was observed, possibly caused by residual cellulose from discharges of sulfite pulping wastes. FISH revealed physiologically active bacteria in most sediment layers from the surface down to the depth of about 60 cm, including members of Desulfitobacterium (D.) and Sulfurospirillum. The presence of D. dehalogenans was confirmed by its partial 16S rRNA gene sequence. Conclusions Results of chemical sediment analyses demonstrated high loads of organochlorine compounds, particularly of PCDD/F. Several years after stopping the waste water discharge to Spittelwasser creek, this sediment remains a main source for pollution of the downstream river system by way of the ongoing mobilization of sediment during high floods. As indicated by our enzyme activity measurements, the decomposition potential for organic matter is low in organochlorine-rich sediment layers. In contrast, the comparably higher enzyme activities in less organochlorine-polluted sediment layers as well as the presence of physiologically active bacteria suggest a considerable potential for natural attenuation. Recommendations and Perspectives From our data we strongly recommend to explore the degradative capacity of sediment microorganisms and the limits for in situ activity towards specific sediment pollutants in more detail. This will give a sound basis for the integration of bioremediation approaches into general concepts to reduce the risk that permanently radiates from this highly contaminated sediment. Submission Editor: Dr. Henner Hollert (Henner.Hollert@urz.uniheidelberg.de)     

Groundwater mapping: An analysis of the United States Hydrological Investigation Atlas Series

Groundwater mapping is a critical component of efficient water resource management today. Difficulties arise when highly specialized and complex groundwater data are collected and presented in map form. This is an analysis of the map content and its presentation in the USGS Hydrological Investigation Atlas Series. This analysis reveals the problems to be surmounted in mapping groundwater information. The technical nature of the groundwater data requires special design considerations.     

Xenoestrogens in the River Elbe and its tributaries

4-Alkylphenols, 4-alkylphenol ethoxylates, 4-alkylphenoxy carboxylates, bisphenol A, bisphenol F, 4-hydroxyacetophenon, 4-hydroxybenzoic acid and steroid hormones were analyzed in water samples of the River Elbe and its tributaries Schwarze Elster, Mulde, Saale, Havel and Schwinge. Additionally, freshly deposited sediments (FDS, composite samples) of the River Elbe and its tributaries were analyzed. The concentrations in water samples ranged from (in ng/l): bisphenol A 4 to 92, branched nonylphenol 13 to 87, branched nonylphenol ethoxylates <0.5 to 120, 4-tert. nonylphenoxy carboxylates <10 to 940 and 4-hydroxybenzoic acid 4 to 12. Steroid hormones were only detected in the Czech tributaries Jizera and Vltava in concentrations near the limit of quantification. In FDS samples the concentrations amounted to (in g/kg d.w.): bisphenol A 10-380, branched nonylphenol 27-430, branched nonylphenol ethoxylates 24-3700, nonylphenoxy carboxylates <50 and 4-hydroxybenzoic acid 23-4400. Increased bisphenol A concentrations were found in water and FDS samples taken from the Czech-German border at Schmilka and the mouth of the Schwinge (only water sample). According to studies conducted in the Elbe Estuary and the German Bight, the River Elbe must be considered as a major source of pollution for the North Sea in respect of the compounds analyzed. A comparison of bisphenol A concentrations, 4-alkylphenols and the corresponding ethoxylates analyzed in the River Elbe and its tributaries with those found in other German surface waters indicated a low level of contamination. The evaluation of the data based on LOEC-values indicated that the concentrations were well below the effectivity threshold for some 4-alkylphenols. According to recent ecotoxicological investigations, for example, with prosobranch snails, bisphenol A concentrations found in water samples of the River Elbe and its tributaries may well be detrimental to aquatic organisms. On the basis of the monitoring data and its implications for estrogenic potency the inclusion of bisphenol A in the list of priority substances (European Union Directive 2000/60/EC, Annex X) should be considered.     

Biodiversity and Conservation of Plants in Brazil

Abstract:  With more than 56,000 species (excluding fungi), Brazil has one of the richest floras in the world—nearly 19% of the world flora. Our knowledge of the diversity and status of nonvascular plants in Brazil is still fragmentary, although localized studies on algae have revealed loss of species resulting from environmental pollution. Emphasis on local floral surveys, rather than wider taxonomic studies, has obscured estimates of national totals for most taxonomic groups. Knowledge of angiosperms, especially monocotyledons (of which 45% of the species are endemic), is more complete than most. For this group figures are more reliable, with some distribution patterns, endemism levels, and centers of diversity identified. Much, however, still awaits discovery. Coordinated efforts to catalog Brazil's flora are in progress and include projects such as the conservation priority-setting workshops of the Brazilian Ministry of the Environment, which have identified key conservation areas in the major biomes; development of threatened species lists for plants; and the assembly of type data on species of northeastern Brazil through the Darwin Initiative—all of which greatly assist in increasing our knowledge. These initiatives also underline the urgent need to expand the numbers and geographic spread of projects on plant systematics and taxonomy in Brazil, a measure that demands adequate provision of funding and training programs for plant specialists. Finally, Brazil's environmental agency (IBAMA) could play a proactive role in opening protected areas under its jurisdiction, thereby facilitating botanical research by university departments and research institutes.     

Von Warzen und Viren

The discovery that papillomaviruses are correlated with various types of cancer in man has led to increased interest in this virus group. A more detailed study of these viruses has only become possible with the introduction of recombinant DNA techniques. The most thoroughly studied representative, the bovine papillomavirus type 1, has now itself become a tool in genetic engineering.     

Der Einsatz von Pflanzentests bei der Sedimentbewertung

Up to now, sediment studies have mainly used standardized aquatic bioassays with organisms of the three trophic levels. Among these, algae are the only representatives of the entire plant kingdom. Bioassays with higher plants have hardly been used for the assessment of sediments. The aim of the present study is to demonstrate that the use of higher plants in biotests for analyses of anthropogenically contaminated sediments yields valuable results, which may be included in a concept for the integrated assessment of waters. The contamination by environmental chemicals was determined in the River Elbe by means of samples taken at the Fahlberg-List industrial site at Magdeburg in combination with studies in a reference area on the Müritz-Elde Waterway (Eldenburger Kanal). Sediment extracts and pore waters were tested with the aquatic lemna test. For comparison, first sediment contact tests withLemna minor were tried out. The whole extract of the sediment from Fahlberg-List Magdeburg and one fraction F5 caused distinct damages of the plants. Obviously, the phytotoxic substances of the whole extract are preferentially concentrated in the highly polar fraction F5. A comparison with chemical analytical data proved that the whole fraction F0 and the fraction F5 were heavily contaminated with chemicals. Assays with pore water from this sediment and with the whole sediment also caused a strong inhibition of growth. These results confirm the high contamination of the sediment from Magdeburg. The tests with the reference sediment suggested only a moderate toxic contamination. The results of this study prove that the selected aquatic plant,Lemna minor, is basically able to indicate contamination. In the aquatic test of the sediment extracts, it showed weak, but very selective, responses to certain classes of contaminants. Fractionating of the sample and subsequent chemical analysis combined with toxicity tests allow to narrow down the groups of substances causing toxic effects. This toxicity was confirmed by analyses of the pore waters and whole sediment samples. Together with other toxicity tests (e.g. standardized bioassays) and combined with biological benthos examinations, an overall judgment can be given for the integrated assessment of waters.