Eelgrass fairy rings: sulfide as inhibiting agent

Distinct ‘fairy rings’ consisting of narrow fringes of eelgrass (Zostera marina L.) expand radially over a bottom of chalk plates outside the calcium carbonate cliffs of the island of Møn, Denmark. We conducted a survey to evaluate possible explanations for the formation of the rings and, more specifically, for the apparent die-off of eelgrass shoots on the inner side of the rings. The fairy rings were up to 15 m in diameter consisting of 0.3- to 1-m-wide zones of sea grass shoots at densities of up to 1,200 shoots m^?2 and rooted in an up to 10-cm-thick sediment layer. On the outer side, shoots expanded over the bare chalk plates. On the inner side, shoots were smaller, had lower absolute and specific leaf growth, shoot density was lower and the sediment eroded leaving the bare chalk with scattered boulders behind. Sediment organic matter and nutrients and tissue nutrient contents were not different among positions. Sediment pools of acid volatile sulfides and chromium-reducible sulfur increased from outer to the middle positions of the rings, and so did total sulfur content of eelgrass tissues, while tissue δ³⁴S isotope ratios, regardless of position in the fringes, were low reflecting substantial invasion of sulfide from the sediment. Neither the clonal growth pattern of eelgrass, sediment burial of shoots, hydrodynamic forcing nor nutrient limitation could explain the ring-shaped pattern. We conclude that the most likely explanation must be found in invasion of eelgrass shoots by toxic sulfide accumulating in the sediment due to low iron availability in the carbonate-rich environment.     

Sustainable management of shellfish resources in Bandon Bay, Gulf of Thailand

Bandon Bay (Surat Thani Province) is one of the most productive coastal areas in southern Thailand. The Tapi River and 18 channels are the main sources of freshwater, nutrients, organic matter and sediment to the bay and the loading of freshwater and nutrients provide essential support for the production of phytoplankton in the estuarine ecosystem. Bandon Bay is important as natural spawning, nursery and feeding grounds for shellfish such as oysters, blood cockles, green mussels, short-necked clams, mud crabs and shrimps, and the estuary also serves as an excellent area for mariculturing of shellfish. In fact, oysters and blood cockles cultured in Bandon Bay are now being exported worldwide. However, Bandon Bay is also a textbook example of overexploitation of coastal resources in the tropics including all the derived changes in the estuarial ecosystem with severe socio-economic consequences. Hence, there is an urgent need for setting up an integrated management plant for a sustainable use of shellfish resources in Bandon Bay. The present study attempts to integrate water quality simulation results, socio-economic data and information on existing shellfish resource use in the process of proposing a set of sustainable management strategies for shellfish resources in Bandon Bay. These strategies involve: (1) using water quality modeling to monitor ecological and environmental changes in shellfish culture beds and their natural habitats in the process of setting up a master plan for management of waste water discharge into Bandon Bay; (2) zoning of shellfish mariculture in the coastal area in order to solve conflicts between resource users; (3) setting up a clear system for taxation of mariculture where the revenue may be used for (4) setting up and managing mangrove strips as filters of pollution and sediment around Bandon Bay; and finally (5) it is suggested to form a committee with members representing all relevant stakeholders plus the local government in order to work on resolving the existing and potential future conflicts over resource usage in Bandon Bay. This methodology may be seen as an important contribution towards a Bandon Bay sustainable management approach, based on the principles of integrated coastal zone management because it is science-based and takes into consideration the needs and perceptions of people involved in coastal resource extraction.     

Assessment of volatile organic compound removal by indoor plants—a novel experimental setup

Indoor plants can remove volatile organic compounds (VOCs) from the air. The majority of knowledge comes from laboratory studies where results cannot directly be transferred to real-life settings. The aim of this study was to develop an experimental test system to assess VOC removal by indoor plants which allows for an improved real-life simulation. Parameters such as relative humidity, air exchange rate and VOC concentration are controlled and can be varied to simulate different real-life settings. For example, toluene diffusion through a needle gave concentrations in the range of 0.10–2.35 μg/L with deviations from theoretical values of 3.2–10.5 %. Overall, the system proved to be functional for the assessment of VOC removal by indoor plants with Hedera helix reaching a toluene removal rate of up to 66.5 μg/m²/h. The mode of toluene exposure (semi-dynamic or dynamic) had a significant influence on the removal rate obtained by H. helix.     

Risk-based economic decision analysis of remediation options at a PCE-contaminated site

Remediation methods for contaminated sites cover a wide range of technical solutions with different remedial efficiencies and costs. Additionally, they may vary in their secondary impacts on the environment i.e. the potential impacts generated due to emissions and resource use caused by the remediation activities. More attention is increasingly being given to these secondary environmental impacts when evaluating remediation options. This paper presents a methodology for an integrated economic decision analysis which combines assessments of remediation costs, health risk costs and potential environmental costs. The health risks costs are associated with the residual contamination left at the site and its migration to groundwater used for drinking water. A probabilistic exposure model using first- and second-order reliability methods (FORM/SORM) is used to estimate the contaminant concentrations at a downstream groundwater well. Potential environmental impacts on the local, regional and global scales due to the site remediation activities are evaluated using life cycle assessments (LCA). The potential impacts on health and environment are converted to monetary units using a simplified cost model.A case study based upon the developed methodology is presented in which the following remediation scenarios are analyzed and compared: (a) no action, (b) excavation and off-site treatment of soil, (c) soil vapor extraction and (d) thermally enhanced soil vapor extraction by electrical heating of the soil. Ultimately, the developed methodology facilitates societal cost estimations of remediation scenarios which can be used for internal ranking of the analyzed options. Despite the inherent uncertainties of placing a value on health and environmental impacts, the presented methodology is believed to be valuable in supporting decisions on remedial interventions.     

A comparison of amniotic fluid alpha-fetoprotein and acetylcholinesterase in the prenatal diagnosis of open neural tube defects and anterior abdominal wall defects

Amniotic fluid samples received for routine prenatal diagnosis of open neural tube defects were used for a study to compare amniotic fluid acetylcholinesterase (AChE) determination using a monoclonal antibody (4F19) enzyme antigen immunoassay and amniotic fluid alpha-fetoprotein (AFP) measurement as diagnostic tests for open neural tube defects. The study was based on 9964 women with singleton pregnancies and known outcome (including 6 with anencephaly and 18 with open spina bifida) having an amniocentesis at 14–23 weeks of gestation. The AChE immunoassay yielded detection rates for anencephaly of 100 per cent (95 per cent confidence interval (CI) 54·07–100 per cent), for open spina bifida of 100 per cent (95 per cent CI 81·47–100 per cent), for anterior abdominal wall defects of 20 per cent (95 per cent CI 0-51-71-64 per cent), and a false-positive rate of 0·22 percent (95 per cent CI 0·14–0·34 per cent) excluding anencephaly, open spina bifida, and anterior abdominal wall defects. For similar detection rates the false-positive rate of the AFP test was significantly higher, 0·74 per cent (95 per cent CI 0·58–0·94 per cent). On the basis of these findings, it is recommended that the technically simple AChE immunoassay should be used on all samples; the AFP test should only be used on the 0·5 per cent of the samples with concentrations of AChE activity ⩾ 8·5 nkat/1 for clear samples and blood-stained samples becoming clear after centrifugation, and ⩾ 25·0 nkat/1 for blood-stained samples that are discoloured after centrifugation; an AFP cut-off level of 2·0 MOM is recommended for this policy. Thereby, the detection rates for anencephaly, open spina bifida, and anterior abdominal wall defects would be 100, 100, and 20 per cent, respectively (95 per cent CIs 54·07–100, 81·47–100, and 0·51–71·64 per cent, respectively), and the false-positive rate would be 0·08 per cent (95 per cent CI 0·03–0·16 per cent) (excluding anencephaly, open spina bifida, and anterior abdominal wall defects).     

Market aspects in product life cycle inventory methodology

In planning a product life cycle inventory analysis, the correct choice of methodology often depends on market information. This paper discusses a number of points in the life cycle inventory methodology (choice of product alternatives, geographical system boundaries, technological levels and co-product allocation rules) where the market aspect becomes obvious and where a disregard for these aspects may lead to serious flaws in the results.     

How does cell-based non-invasive prenatal test (NIPT) perform against chorionic villus sampling and cell-free NIPT in detecting trisomies and copy number variations? A clinical study from Denmark

Objectives

We aimed to compare cell-based NIPT (cbNIPT) to chorionic villus sampling (CVS) and to examine the test characteristics of cbNIPT in the first clinical validation study of cbNIPT compared to cell-free NIPT (cfNIPT).

Material and Methods

Study 1: Women (N = 92) who accepted CVS were recruited for cbNIPT (53 normal and 39 abnormal). Samples were analyzed with chromosomal microarray (CMA). Study 2: Women (N = 282) who accepted cfNIPT were recruited for cbNIPT. cfNIPT was analyzed using sequencing and cbNIPT by CMA.

Results

Study 1: cbNIPT detected all aberrations (32/32) found in CVS: trisomies 13, 18 and 21 (23/23), pathogenic copy number variations (CNVs) (6/6) and sex chromosome aberrations (3/3). cbNIPT detected 3/8 cases of mosaicism in the placenta. Study 2: cbNIPT detected all trisomies found with cfNIPT (6/6) and had no false positive (0/246). One of the three CNVs called by cbNIPT was confirmed by CVS but was undetected by cfNIPT, two were false positives. cbNIPT detected mosaicism in five samples, of which two were not detected by cfNIPT. cbNIPT failed in 7.8% compared to 2.8% in cfNIPT.

Conclusion

Circulating trophoblasts in the maternal circulation provide the potential of screening for aneuploidies and pathogenic CNVs covering the entire fetal genome.     

Environmental indicators for long-range atmospheric transported heavy metals based on national moss surveys

Environmental indicators for long-range atmospheric transported heavy metals have been developed. The indicators are based on data for Pb and Cd from national moss surveys which are performed regularly in Norway. The interpolation programme kriging has been used to transform the data from irregular grids to regular grids. Contour maps have been produced, and areas above estimated background levels for Pb and Cd in mosses have been calculated. The indicators are used to characterise the atmospheric deposition of long-range atmospheric transported heavy metals and monitor the changes with time.     

Characterisation, dissemination and persistence of gentamicin resistant Escherichia coli from a Danish university hospital to the waste water environment

The aim of the study was to investigate the potential spread of gentamicin resistant (GEN(R)) Escherichia coli isolates or GEN(R) determinants from a Danish university hospital to the waste water environment. Waste water samples were collected monthly from the outlets of the hospital bed wards and the inlet of the related waste water treatment plant (WWTP) from October 2002 to August 2003. Waste water samples were also collected monthly from a residential area in the same period to be able to compare the prevalence of GEN(R)E. coli isolates from hospital related and residential waste water. The waste water isolates were compared to GEN(R)E. coli isolates obtained consecutively from September 2002 to September 2003 from patients mainly with urinary tract infections at the hospital with respect to Pulsed Field Gel Electrophoresis (PFGE) profiles. All isolates were investigated for GEN(R) mechanisms (aac(3)-II, aac(3)-IV, ant(2')-I, armA), phenotypic resistance pattern, and virulence genes (hlyA, chuA, sfaS, fogG, malX, traT, iutA, fyuA, iroN, cnf1) to investigate if the hospital and waste water could be reservoirs of antimicrobial resistance and virulence. The ability for GEN(R) determinants to transfer horizontally was investigated by mating experiments. A total of 38, 15, 21, and two GEN(R)E. coli were isolated from patients, the hospital outlets, the inlet of the WWTP, and the residential area, respectively. GEN(R)E. coli were more prevalent in waste water from the hospital and the WWTP than in waste water from the residential area. PFGE profiling revealed no spread of specific patient isolates to the waste water. The aac(3)-II gene was detected both in patient and waste water isolates. Furthermore horizontal transfer of the aac(3)-II gene of patient origin to a recipient was shown in vitro, indicating a potential spread of the gene from patient isolates to waste water isolates. Regardless of origin, most isolates exhibited multi-resistance and contained several virulence genes. In conclusion, our study showed a possible spread of aac(3)-II from the hospital to the waste water. Most of the GEN(R)E. coli isolates from both patients and waste water had a multi-resistant phenotype and contained virulence genes and should therefore be considered reservoirs of antimicrobial resistance and virulence genes.