Uranium uptake by hydroponically cultivated crop plants

Hydroponicaly cultivated plants were grown on medium containing uranium. The appropriate concentrations of uranium for the experiments were selected on the basis of a standard ecotoxicity test. The most sensitive plant species was determined to be Lactuca sativa with an EC₅₀ value about 0.1 mM. Cucumis sativa represented the most resistant plant to uranium (EC₅₀ = 0.71 mM). Therefore, we used the uranium in a concentration range from 0.1 to 1 mM.Twenty different plant species were tested in hydroponic solution supplemented by 0.1 mM or 0.5 mM uranium concentration. The uranium accumulation of these plants varied from 0.16 mg/g DW to 0.011 mg/g DW. The highest uranium uptake was determined for Zea mays and the lowest for Arabidopsis thaliana. The amount of accumulated uranium was strongly influenced by uranium concentration in the cultivation medium. Autoradiography showed that uranium is mainly localized in the root system of the plants tested. Additional experiments demonstrated the possibility of influencing the uranium uptake from the cultivation medium by amendments. Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba up to 2.8 times or 1.9 times, respectively. Phosphate deficiency increased uranium uptake up to 4.5 times or 3.9 times, respectively, by Brassica oleracea and S. alba. In the case of deficiency of iron or presence of cadmium ions we did not find any increase in uranium accumulation.     

An assessment of metal contamination along the Irish coast using the seaweed Ascophyllum nodosum (Fucales, Phaeophyceae)

The relative abundance and variation of Cr, Co, Cd and Pb in Ascophyllum nodosum and intertidal surface sediments from six locations around the coast were assessed over six seasons. Higher Cd and Pb levels in Galway Docks and Cork Harbour were attributed to localised inputs of these metals from municipal and domestic waste, while at a reference site (Ballyconneely), high algal Cr concentrations were considered a function of geological setting rather than anthropogenic loading. Little seasonal variation was observed, with the exception of higher Co levels in plants in winter, associated with growth dynamics and increased fluvial inputs. In comparison with previously published data for metals in A. nodosum from the North Atlantic, with the exception of localised hot spots, the Irish coastline is still a relatively pristine environment. A. nodosum may be successfully and easily used as a biomonitor of metal contamination in coastal waters.     

Detection and enumeration of colonic mucosal cells in amniotic fluid using a colon epithelial-specific monoclonal antibody

Since its introduction, prenatal diagnosis of chromosomal and metabolic disorder by mid-trimester amniocentesis has relied upon the use of a mixture of fetal cells obtained from amniotic fluid. Little knowledge has been gained in the sorting of these cells for diagnosis of tissue-specific disorders. In an attempt to determine the contribution of fetal colonic mucosal cells to the overall amniocyte population, we used the colonic epithelial-specific monoclonal antibody (MC-Ab) 7E₁₂H₁₂, IgM isotype. Specimens of the small intestine, colon, buccal mucosa, kidney, urinary bladder, and umbilical cord were obtained from electively aborted normal fetuses of 12–28 weeks' gestation. All of these specimens were examined with 7E₁₂H₁₂ by the immunoperoxidase technique. The MC-Ab reacted with the colonic epithelial cells but not with any of the other tissues. In addition, 40 amniotic fluid samples obtained from women between 16 and 18 weeks of gestation, who underwent amniocentesis because of advanced maternal age, were tested using a fluorescent activated cell sorter. Among the amniotic fluid specimens examined, 18·4 ± 10·3 percent cells reacted with 7E₁₂H₁₂. Double immunofluorescence studies revealed that all Mc-Ab-stained cells contained secretory component, confirming that they were epithelial in origin. All fetuses whose amniotic fluid was analysed had normal karyotypes and amniotic fluid alpha-fetoprctein levels that were also normal. This study demonstrates that cell-specific Mc-Ab can be used to detect colon cells in the amniotic fluid and that colon cells contribute significant numbers in the mixture of amniotic fluid cells. This technique could be helpful in the prenatal diagnosis of disorders in which the flow of amniotic fluid through the fetal intestine is impaired, such as cystic fibrosis, imperforate anus, Hirschsprung aganglionic megacolon, and intestinal atresia.     

Training future experts in “biodiversity and ecosystem services”: a progress report

Biodiversity is essential for multiple aspects of human life and well-being, but many current assessments of the functioning of biodiversity and ecosystems, understanding of risks posed by environmental change and the best practice of their management of ecosystems are lacking a unified scientific and conceptual basis. Methods such as scenario analysis, and terms such as ecosystem services, are widely used, but their meaning is understood in many different ways depending on context, user needs and experience of researchers. In order to advance the conceptual basis for ecosystem analysis and management in a rapidly changing world, as well as the ability of young scientists to reflect upon these concepts, we have organised five 2-week-long summer schools in Peyresq, a remote village in the Southern French Alps. In total 173 participants have worked intensively with 69 experienced researchers and a team of conveners and tutors in order to discuss a broad range of views on topics on ecosystem analysis and functioning. Topics ranged from conditions of and threats to various ecosystems due to environmental change, models and scenarios for assessment, stakeholder perceptions and needs for information, to the social and economic contexts for biodiversity. We report our experience from these schools, present the training concept which has emerged from them and suggest lines of further development.

Pesticide handling practices by vegetable farmer in Kenya

Pesticide handling practices have a strong bearing on the exposure of toxic effects to target and nontarget organism. A clear understanding of determinants of pesticide handling practices is a precondition in the design and implementation of policy intervention. To accomplish this, a household survey of 425 respondents was conducted in 2008. Majority of the farmers (85 %) had inappropriately handled pesticides, mainly through, unsafe storage (23 %), unsafe disposal of leftover in either sprays solutions, or rinsate and empty pesticide containers (40 %), failure to wear the required minimum protective gear (68 %), or overdosed pesticides (27 %). However, majority of those farmers were aware of the risks of pesticide use, with over 81 % expressing the view that pesticides have harmful effects on human health, livestock, beneficial arthropods, and on water. Econometric models showed that pesticide handling practices were significantly influenced by variation in record keeping, main source advice on pesticide use, toxicity of pesticide, and geographical location. Pesticide risk perception and negative impacts experiences had no association with handling practices. The study recommends policymakers to design effective, participatory, and location targeted outreach programmes, which deal specifically on promotion of record keeping and reduction in use of harmful pesticides.     

Distribution of common dolphins (Delphinus spp.) in the western Atlantic Ocean: a critical re-examination

Due to indications that misidentification (largely confusion among dolphins of the genera Delphinus and Stenella) in the past had led to erroneous assumptions of distribution of the two species of common dolphins (Delphinus delphis and D. capensis) in the western Atlantic Ocean, we conducted a critical re-examination of records of the genus Delphinus from this region. We compiled 460 ‘plottable’ records, required support for confirmation of genus and species identifications, and found many records lacking (and some clearly misidentified). When we plotted only the valid records (n = 364), we found evidence of populations in only three areas, and apparent absence throughout much of the tropical/subtropical regions. Off the east coast of the US and Canada, D. delphis is found from the Georgia/South Carolina border (32°N) north to about 47–50°N off Newfoundland. Since the 1960s, they have apparently been absent from Florida waters. There is no evidence that dolphins of the genus occur in the Gulf of Mexico. Reports of common dolphins from most of the Caribbean Basin are also rejected, and the only place in that region where they are confirmed to occur is off central-eastern Venezuela (a coastal D. capensis population). Off eastern South America, common dolphins appear to be restricted to south of 20°S. There is a coastal long-beaked population found in the South Brazil Bight, and one or more short-beaked populations south and offshore of this (ranging south to at least northern Argentina). The results are very different from commonly-accepted patterns of distribution for the genus in the Atlantic. Most areas of distribution coincide with moderate to strong upwelling and common dolphins appear to avoid warm, tropical waters. This study shows that great care must be taken in identification of similar-appearing long-beaked delphinids, and that uncritical acceptance of records at face value can lead to incorrect assumptions about the ranges of the species involved.     

Assessing vulnerabilities to the effects of global change: an eight step approach

In the recent years, global environmental change research has seen increased attention to the concept of vulnerability. There have been a growing number of vulnerability assessments, but relatively little discussion on appropriate and common methods. Here we propose a method to guide vulnerability assessments of coupled human–environment systems toward a common objective: informing the decision-making of specific stakeholders about options for adapting to the effects of global change. We suggest five criteria vulnerability assessments must at least possess to achieve this objective. They should have a knowledge base from various disciplines and stakeholder participation, be place based, consider multiple interacting stresses, examine differential adaptive capacity, and be prospective as well as historical. On the basis of these criteria, we present a general methodological guideline of eight steps. To examine whether these eight steps, if attentively coordinated, do in fact achieve the criteria, and in turn satisfy the objective of the assessment, we discuss two case studies. We expect most readers to identify some of the steps as part of their well-established disciplinary practices. However, they should also identify one or more steps as uncommon to their research traditions. Thus taken together the eight steps constitute a novel methodological framework. We hypothesize that if researchers employ this framework, then the products of the research will (1) achieve the objective of preparing stakeholders for the effects of global change on a site-specific basis, and (2) further the “public good” of additional insights through cross-study comparisons of research projects designed according to common principles.