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)     

Digital sustainability: basic conditions for sustainable digital artifacts and their ecosystems

The modern age has heralded a shift from the industrial society, in which natural resources are crucial input factors for the economy, towards a knowledge society. To date, sustainability literature has treated knowledge—and in particular digital artifacts—mainly as a means to the end of achieving sustainable development. In this conceptual paper, we argue that digital artifacts themselves ought also to be considered as resources, which also need to be sustainable. While over-consumption is a problem facing natural resources, with sustainable digital artifacts, underproduction, and underuse are the biggest challenges. In our view, the sustainability of digital artifacts improves their potential impact on sustainable development. A theoretical foundation for digital artifacts and their ecosystem allows us to present the relevant research on digital information, knowledge management, digital goods, and innovation literature. Based on these insights, we propose ten basic conditions for sustainable digital artifacts and their ecosystem to ensure that they provide the greatest possible benefit for sustainable development. We then apply those characteristics to four exemplary cases: Linux kernel development, Bitcoin cryptocurrency, the Wikipedia project, and the Linking Open Drug Data repositories. The paper concludes with a research agenda identifying topics for sustainability scholars and information systems academics, as well as practitioners. A number of suggestions for future studies on digital sustainability are also put forward.     

Land use and land cover change affecting habitat distribution in the Segara Anakan lagoon, Java, Indonesia

This study quantifies and spatially characterizes land use and land cover changes in the Segara Anakan lagoon (SAL), Java, Indonesia, from 1987–2006. Classification of four satellite (SPOT) images from the years 1987, 1995, 2004 and 2006 and field ground truth data from 2004 and 2005 were used for map generation. The results show major changes in the western area of the SAL, with large area increases of rice fields, dry land agriculture, aquaculture and rural areas, and decreases in mangrove cover, mud flat and lagoon area. In the eastern area, minor decreases in mangrove area and increase in aquaculture, rural and industrial areas were also observed. Changes are due to the filling of the lagoon with riverine sediments derived from the hinterland and to mangrove conversion and resources exploitation. The results of this study provide basic information which is required for developing measures towards a sustainable management and conservation of the SAL.     

Long-term change in drivers of forest cover expansion: an analysis for Switzerland (1850-2000)

Regional Environmental Change - The spatial distribution of forests in Europe represents the legacy of centuries of human land use decisions. Due to the limited availability of historical data,...     

Turner syndrome-omphalocele association: Incidence,karyotype, phenotype and fetal outcome

Objective

Omphalocele is known to be associated with genetic anomalies like trisomy 13, 18 and Beckwith–Wiedemann syndrome, but not with Turner syndrome (TS). Our aim was to assess the incidence of omphalocele in fetuses with TS, the phenotype of this association with other anomalies, their karyotype, and the fetal outcomes.

Method

Retrospective multicenter study of fetuses with confirmed diagnosis of TS. Data were extracted from a detailed questionnaire sent to specialists in prenatal ultrasound.

Results

680 fetuses with TS were included in this analysis. Incidence of small omphalocele in fetuses diagnosed ≥12 weeks was 3.1%. Including fetuses diagnosed before 12 weeks, it was 5.1%. 97.1% (34/35) of the affected fetuses had one or more associated anomalies including increased nuchal translucency (≥3 mm) and/or cystic hygroma (94.3%), hydrops/skin edema (71.1%), and cardiac anomalies (40%). The karyotype was 45,X in all fetuses. Fetal outcomes were poor with only 1 fetus born alive.

Conclusion

TS with 45,X karyotype but not with X chromosome variants is associated with small omphalocele. Most of these fetuses have associated anomalies and a poor prognosis. Our data suggest an association of TS with omphalocele, which is evident from the first trimester.     

Sensitivity to biologically relevant odours may exceed the sum of component thresholds

Summary In four fruit-eating bats sniff-rate analysis revealed the threshold value for natural banana odour to be 1 × 10^–4 vol% of head-space while the threshold values for its major components were found to be 3–6 orders of magnitude higher; even the total of molecules present at the threshold dilution of banana odour was 2 orders of magnitude below the lowest threshold values obtained for single components. Thus, the responsiveness of the bats to threshold concentration of natural banana odour is discussed as an example of synergism of stimuli.     

Genotoxic effects of metals on human salivary gland tissue and lymphocytes as detected by the Comet assay

The etiology of salivary gland malignancies still remains unclear. Metal compounds are of special interest since they show ubiquitous presence in the environment, are present in many working places, and are accepted (co-)carcinogens in some other malignancies. Metals enter the body as xenobiotics by inhalation or ingestion. This study investigated the genotoxic potential of sodium dichromate (Na₂Cr₂O₇), nickel sulfate (NiSO₄), cadmium sulfate (CdSO₄) and zinc chloride (ZnCl₂) on human salivary gland cells and lymphocytes. Macroscopically healthy tissue of salivary glands was harvested from 46 patients during surgery and isolated to single cells by enzymatic digestion. The cells were incubated with Na₂Cr₂O₇, NiSO₄, CdSO₄ or ZnCl₂. Na₂Cr₂O₇ was also incubated in combination with the other metal compounds listed. Carcinogenic and co-carcinogenic effects of cadmium were tested by incubation with Na₂Cr₂O₇ and consecutive repair intervals. DNA damage and repair were evaluated by the Comet assay, determining DNA-strand breaks. The extent of damage was quantified using a digital analysis system. Na₂Cr₂O₇ produced significantly enhanced DNA-strand breaks in human salivary gland tissue and lymphocytes. All other metal compounds exerted no damaging effect on both cell types. Co-incubation of Na₂Cr₂O₇ with the other metals revealed a significant additive effect only for CdSO₄. Specific analysis of the influence of cadmium showed a reduction of DNA-repair after Na₂Cr₂O₇-induced strand breaks in salivary gland cells. This study provides evidence that exposure to distinct metals may significantly contribute to malignant salivary gland tumors. In consequence, further studies as epidemiological and toxicological data are warranted to determine the role of distinct metals as potential (co-) carcinogens.     

Analysis and decomposition of condensed tannins in tree leaves

The decomposition of leaf litter is controlled by several factors. One factor that may play an important role is the content of condensed tannins (proanthocyanidins). Here we designed a combined method to isolate proanthocyanidins from leaf extracts, to convert them to anthocyanidins, and to quantify individual anthocyanidins exactly with a new, simple, but sensitive high-performance liquid chromatography method. We used this method to show composition of proanthocyanidins and to monitor degradation of proanthocyanidins and individual constituents in leaf litter in an aquatic environment over time. Despite the rapid decrease in the initial concentrations, a fraction of the proanthocyanidins remained detectable for several weeks.     

Compliance and Emissions Trading under the Kyoto Protocol: Rules for Uncertain Inventories

A solution is proposed for proving compliance with emission targets and for emissions trading in the event of uncertainties in reported emission inventories. The solution is based on the undershooting concept, from which the mathematical conditions for both proving compliance with a risk α and calculating effective emissions for trading are derived. Based on the reported emission units, the number of permits granted is reduced in proportion to the uncertainty in the inventory. A country whose inventory has higher uncertainty is thereby allotted fewer permits than a country with the same inventory but smaller uncertainty.     

Underlying reasons of the controversy over adverse effects of Bt toxins on lady beetle and lacewing larvae

In their recent study, Hilbeck et al. (2012) report that Cry1Ab causes lethal effects on larvae of the ladybird beetle Adalia bipunctata when fed directly to the predator. Such toxic effects were not previously observed in a direct feeding study conducted by us (álvarez-Alfageme et al. 2011). Because Hilbeck et al. (2012) claim that our study design did not allow us to detect any adverse effects we provide arguments for the value and relevance of our study in this commentary. Furthermore we discuss two additional published studies that have not revealed any direct effects of Cry1Ab on larvae of A. bipunctata and are not mentioned by Hilbeck et al. (2012). One of the studies was conducted in our laboratory under more realistic exposure conditions (álvarez-Alfageme et al. 2011). Feeding A. bipunctata larvae with spider mites reared on Bt maize did not reveal any adverse effects on lethal and sublethal parameters of the predator. This was despite the fact that the larvae had ingested high amounts of biologically-active Cry1Ab protein. Thus, we do not see verified evidence that A. bipunctata larvae are sensitive to Cry1Ab at realistic worst-case exposure concentrations. This, together with the fact that A. bipunctata will be little exposed to Cry1Ab under field conditions, allows us to conclude that the risk of Bt maize to this predator is negligible. Support for this comes from the results of many Bt maize field studies that have not revealed evidence for direct Cry1Ab-effects on non-Lepidoptera species.