A transition in the Dutch wastewater system? The struggle between discourses and with lock-ins

ABSTRACT

Recently, calls have increased for a paradigm shift or transition towards resource recovery and a circular economy in the Dutch wastewater system. However, we have observed diverging interpretations on the nature of the transition. This reflects the political environment of sustainability transitions: political struggle emerges over the definition of problems, futures and strategies to be used. In order to help clarify the emerging debate and identify political choices, we conducted a discourse analysis. We identified three discourses that reveal some of the political choices to be made. One discourse is becoming dominant and focusses on optimising the large-scale infrastructure, market development and legislative changes. The discourse draws on the existing infrastructure and current political-economic institutions, which gives it an advantage in becoming dominant. Our findings also suggest that this discourse shapes a transition pathway that is characterised by lock-in effects and, at most, incremental changes instead of a fundamental shift in the established Dutch wastewater system.     

Evidence of Al-Cr interactions affecting Cr-leaching from waste incineration ashes

Leaching tests on flue gas ashes from waste incineration showed low leaching of Cr from ashes that under moist anaerobic conditions also produced hydrogen gas. In some cases, also the redox levels (aerobic/anaerobic conditions) during the leaching test affected Cr leaching. Aerobic ashes tested in an open batch leaching test leached Cr up to 2-3 orders of magnitude more than the ashes kept moist under anaerobic conditions and tested in a closed leaching test. Model experiments showed that metallic Al could reduce Cr and at the same time produce H(2). The hydrogen gas per se could not reduce Cr. Laboratory experiments with ashes provided evidence that metallic Al, present naturally in the ashes or amended, could reduce Cr under moist anaerobic, but not under aerobic storage. Significant Cr reduction was linked to, but not caused by hydrogen formation. The reduced Cr seemed to be partially reoxidizable upon aeration or drying. The observations presented provide a basis for understanding the complexity of Cr leaching from waste incineration ashes, as for example, why some chemical stabilization methods increase Cr leaching, and point out the need for standardizing leaching test conditions with respect to Cr.     

The history of seabird colonies and the North Water ecosystem: Contributions from palaeoecological and archaeological evidence

The North Water (NOW) polynya is one of the most productive marine areas of the Arctic and an important breeding area for millions of seabirds. There is, however, little information on the dynamics of the polynya or the bird populations over the long term. Here, we used sediment archives from a lake and peat deposits along the Greenland coast of the NOW polynya to track long-term patterns in the dynamics of the seabird populations. Radiocarbon dates show that the thick-billed murre (Uria lomvia) and the common eider (Somateria mollissima) have been present for at least 5500 cal. years. The first recorded arrival of the little auk (Alle alle) was around 4400 cal. years bp at Annikitsoq, with arrival at Qeqertaq (Salve Ø) colony dated to 3600 cal. years bp. Concentrations of cadmium and phosphorus (both abundant in little auk guano) in the lake and peat cores suggest that there was a period of large variation in bird numbers between 2500 and 1500 cal. years bp. The little auk arrival times show a strong accord with past periods of colder climate and with some aspects of human settlement in the area.     

Algal tests with soil suspensions and elutriates: a comparative evaluation for PAH-contaminated soils

An algal growth inhibition test procedure with soil suspensions is proposed and evaluated for PAH-contaminated soil. The growth rate reduction of the standard freshwater green alga Pseudokirchneriella subcapitata (formerly known as Selenastrum capricornutum) was used as the toxicity endpoint, and was quantified by measuring the fluorescence of solvent-extracted algal pigments. No growth rate reduction was detected for soil contents up to 20 g/l testing five non-contaminated Danish soils. Comparative testing with PAH-contaminated soil elutriates and soil suspensions showed that the suspensions had toxicity endpoints 2.5-3000 times lower than tests with the corresponding elutriates. Algal growth inhibition tests with soil suspensions are recommended for screening purposes as a supplement to elutriate testing. Experiments with a phenanthrene-spiked soil, showed that the sorbed compound did not contribute to the toxicity. However, the soil did act as a reservoir for phenanthrene, allowing desorption to occur continuously during the algal test which maintained higher concentrations of phenanthrene in the dissolved phase. Phenanthrene-spiked soil incubated for 90 days before algal testing, resulted in a reduction of the toxicity to P. subcapitata by a factor of 76 (from EC10 = 0.3 to 23.6 g soil/l). However, during this 90-day period the total concentration of phenanthrene in the soil decreased by 38% (from 322 to 199 mg/kg) indicating that phenanthrene in the aged soil had become less bioavailable.     

Organophosphates in aircraft cabin and cockpit air--method development and measurements of contaminants

Methods for measurements and the potential for occupational exposure to organophosphates (OPs) originating from turbine and hydraulic oils among flying personnel in the aviation industry are described. Different sampling methods were applied, including active within-day methods for OPs and VOCs, newly developed passive long-term sample methods (deposition of OPs to wipe surface areas and to activated charcoal cloths), and measurements of OPs in high-efficiency particulate air (HEPA) recirculation filters (n = 6). In total, 95 and 72 within-day OP and VOC samples, respectively, have been collected during 47 flights in six different models of turbine jet engine, propeller and helicopter aircrafts (n = 40). In general, the OP air levels from the within-day samples were low. The most relevant OP in this regard originating from turbine and engine oils, tricresyl phosphate (TCP), was detected in only 4% of the samples (min-max 相似文献   

Inclusion of sex chromosomes in noninvasive prenatal testing in Asia,Australia, Europe and the USA: A survey study

Objective

To examine the extent to which sex chromosomes are included in current noninvasive prenatal testing (NIPT) and the reporting practices with respect to fetal chromosomal sex and sex chromosome aberrations (SCAs), in addition to an update on the general implementation of NIPT.

Method

A questionnaire addressing the research objectives was distributed by email to fetal medicine and clinical genetics experts in Asia, Australia, Europe and the USA.

Results

Guidelines on NIPT are available in the majority of the included countries. Not all existing guidelines address reporting of fetal chromosomal sex and SCAs. In most settings, NIPT frequently includes sex chromosomes (five Australian states, China, Hong Kong, Israel, Singapore, Thailand, USA and 23 of 31 European countries). This occurs most often by default or when parents wish to know fetal sex. In most settings, a potential SCA is reported by stating the risk hereof as “low” or “high” and/or by naming the SCA. Less than 50% of all pregnant women receive NIPT according to respondents from three Australian states, China, Israel, Singapore, Thailand and 24 of 31 European countries. However, this percentage, the genomic coverage of NIPT and its application as primary or secondary screening vary by setting.

Conclusion

In most of the studied countries/states, NIPT commonly includes sex chromosomes. The reporting practices concerning fetal chromosomal sex and SCAs are diverse and most commonly not addressed by guidelines. In general, NIPT is variably implemented across countries/states.     

Investigating the potential for different scooter and car exhaust emissions to cause cytotoxic and (pro-)inflammatory responses to a 3D in vitro model of the human epithelial airway

The aim of this study was to compare the cytotoxicity and the (pro-)inflammatory responses of two-stroke (direct injection and carburetor technology) and four-stroke scooter and diesel car exhaust emissions on lung cells in vitro. This was analyzed by exposing a 3D in vitro model of the epithelial airway (consisting of human bronchial epithelial cells (cell line 16HBE14o^?) combined with human whole blood monocyte-derived macrophages and dendritic cells) to physically characterized exhaust emissions. Biological endpoints of cytotoxicity (lactate dehydrogenase release), as well as pro-inflammatory cytokine (tumor necrosis factor (TNF)-α) and inflammatory chemokine (interleukin(IL)-8) stimulation were examined. Two-stroke direct injection scooter exhaust contained the highest particle number concentration and nitrogen oxides (NO _x ) concentrations and the emissions from the two-stroke carburetor scooter contained the highest hydrocarbon and lowest NO _x concentrations. The four-stroke scooter emitted the highest carbon monoxide concentration whereas the cars emitted the lowest. The combination of various technical optimizations for the two-stroke direct injection scooter (particle filter, oxidative catalyst, better oil and fuel) reduced the total emissions strongly and the TNF-α concentration significantly (p?相似文献