In vivo measurements of the internal pH of Hediste (Nereis) diversicolor (Annelida, Polychaeta) exposed to ambient sulphidic conditions using pH microelectrodes

 The effect of different ambient sulphide concentrations on the internal pH regime of Hediste (Nereis) diversicolor was studied under in vivo conditions using liquid membrane pH microelectrodes, a method which is new to marine sciences. As a case study, the hypothesis was tested whether organisms exposed to ambient sulphidic conditions are able to lower their internal pH which, in effect, would reduce sulphide influx into the animals and thus could represent an effective detoxification mechanism. It was shown that a significant lowering of the internal pH occurred within only 20 min after adding sulphide. This pH lowering appeared to be dependent on the external sulphide concentration of the ambient medium and showed a saturation beyond a threshold level of about 130 μM. It is discussed whether this sulphide-induced pH drop is an active regulatory mechanism and acts as an effective protection mechanism against sulphide during short-term exposures. Received: 1 June 1999 / Accepted in revised form: 3 May 2000     

Transfer von PCDD/F und anderen organischen Umweltchemikalien im System Boden-Pflanze-Luft I. Modellierung des Transferverhaltens

Die Massenbilanz von PCDD/F—insbesondere von 2,3,7,8-TCDD—im System Boden-Pflanze-Luft wird mit einem einfachen konzeptuellen Modell berechnet. Die wichtigsten Ergebnisse sind:

Food web assessments in the Baltic Sea: Models bridging the gap between indicators and policy needs

Ecosystem-based management requires understanding of food webs. Consequently, assessment of food web status is mandatory according to the European Union’s Marine Strategy Framework Directive (MSFD) for EU Member States. However, how to best monitor and assess food webs in practise has proven a challenging question. Here, we review and assess the current status of food web indicators and food web models, and discuss whether the models can help addressing current shortcomings of indicator-based food web assessments, using the Baltic Sea as an example region. We show that although the MSFD food web assessment was designed to use food web indicators alone, they are currently poorly fit for the purpose, because they lack interconnectivity of trophic guilds. We then argue that the multiple food web models published for this region have a high potential to provide additional coherence to the definition of good environmental status, the evaluation of uncertainties, and estimates for unsampled indicator values, but we also identify current limitations that stand in the way of more formal implementation of this approach. We close with a discussion of which current models have the best capacity for this purpose in the Baltic Sea, and of the way forward towards the combination of measurable indicators and modelling approaches in food web assessments. Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01692-x.     

Processes in informal end-processing of e-waste generated from personal computers in Vietnam

Informal treatment of e-waste plays an important role in many countries which have no or weak formal waste management structures. One of the challenges for assessing informal e-waste recycling technologies is to identify their disadvantages and potential technology improvement. The analysis of informal recycling processes starts with a balance of input and output materials for each of the processes. Main obstacles are the fact that in most cases, mixed or variety materials serve as input and, secondly by nature, the informal sector does not systematically measure and monitor the process. This study presents the processes and available data for informal e-waste recycling of desktop personal computer as it consists of components made of plastic and many metals within the Vietnamese context. To identify the most relevant processes, critical flows and technology gap, two scenarios are compared: (1) current situation in which recycling activities are taken in recycling craft villages and (2) appropriately selected BAT. The selected materials from e-waste cover a wide range of recycling processes and technologies: Printed Circuit Board treatment, metal (ferrous metal, aluminum and copper) and plastic recycling.

     

An example of the prisoner's dilemma in biochemistry

Two strains of microorganisms that both use sugar as energy resource, but which may choose between two different pathways of ATP production, are studied from a game-theory point of view. We consider these pathways as distinct strategies to which we assign payoffs that are proportional to the expected steady-state number of individuals sustainable on the basis of these strategies. In a certain parameter range, we find that the payoffs fulfil the conditions for the prisoner's dilemma. Therefore, cooperative behaviour is unlikely to occur, unless additional factors intervene. In fact, the yeast Saccharomyces cerevisiae uses a competitive strategy by fermenting sugars even under aerobic conditions, thus wasting its own resource. The simple quantifiable structure of the model should enable access to an experimentally determined payoff matrix.     

The impact of point source pollution on shallow groundwater used for human consumption in a threshold country

Many developing and threshold countries rely on shallow groundwater wells for their water supply whilst pit latrines are used for sanitation. We employed a unified strategy involving satellite images and environmental monitoring of 16 physico-chemical and microbiological water quality parameters to identify significant land uses that can lead to unacceptable deterioration of source water, in a region with a subtropical climate and seasonally restricted torrential rainfall in Northern Argentina. Agricultural and non-agricultural sources of nitrate were illustrated in satellite images and used to assess the organic load discharged. The estimated human organic load per year was 28.5 BOD(5) tons and the N load was 7.5 tons, while for poultry farms it was 9940-BOD(5) tons and 1037-N tons, respectively. Concentrations of nitrates and organics were significantly different between seasons in well water (p values of 0.026 and 0.039, respectively). The onset of the wet season had an extraordinarily negative impact on well water due in part to the high permeability of soils made up of fine gravels and coarse sand. Discriminant analysis showed that land uses had a pronounced seasonal influence on nitrates and introduced additional microbial contamination, causing nitrification and denitrification in shallow groundwater. P-well was highly impacted by a poultry farm while S-well was affected by anthropogenic pollution and background load, as revealed by Principal Component Analysis. The application of microbial source tracking techniques is recommended to corroborate local sources of human versus animal origin.     

Modelling economic impacts and adaptation to extreme events: Insights from European case studies

Adaptation to climate change in Europe has only recently become a true policy concern with the management of extreme events one priority item. Irrespective of future climatic changes increasing the need for systematic evaluation and management of extremes, weather-related disasters already today pose substantial burdens for households, businesses and governments. Research in the ADAM project identified substantial direct risks in terms of potential crop and asset losses due to combined drought and heatwave, as well as flood hazards in Southern and Eastern Europe, respectively. This paper focuses on the indirect, medium to longer term economic risks triggered by the direct risks and mediated by policy responses. We present a selection of three economic impact and adaptation assessments and modelling studies undertaken on extreme event adaptation in Europe. Responding to a need for more economically based adaptation assessments, we address some relatively unresearched issues such as the understanding of past adaptation, the role of market response to impacts as well as government’s ability to plan for and share out extreme event risks. The first analysis undertakes an empirical exploration of observed impacts and adaptation in the agricultural sector in the UK comparing the impact of consecutive extreme events over time in order to determine whether adaptation has occurred in the past and whether this can be used to inform future estimates of adaptation rates. We find that farmers and the agricultural sector clearly have adapted to extreme events over time, but whether this rate can be maintained into the future is unclear, as some autonomous adaptation enacted seemed rather easy to be taken. Markets may mediate or amplify impacts and in the second analysis, we use an economic general equilibrium model to assess the economic effects of a reduction in agricultural production due to drought and heatwave risk in exposed regions in Spain. The analysis suggests that modelled losses to the local economy are more serious in a large-scale scenario when neighbouring provinces are also affected by drought and heatwave events. This is due to the supply-side induced price increase leading to some passing on of disaster costs to consumers. The simulation highlights the importance of paying particular attention to the spatial and distributional effects weather extremes and possibly changes therein induced by climate change may incur. Finally, we discuss how national governments may better plan their disaster liabilities resulting from a need to manage relief and reconstruction activities post event. We do so using a risk based economic planning model assessing the fiscal consequences associated with the coping with natural extremes. We identify large weather-related disaster contingent liabilities, particularly in the key flood hot spot countries Austria, Romania, and Hungary. Such substantial disaster liabilities (“hidden disaster deficits”) when interacting with weak fiscal conditions may lead to substantial additional stress on government budgets and reduced fiscal space for funding other relevant public investment projects. Overall, our paper suggests the importance of respecting the specific spatial and temporal characteristics of extreme event risk when generating information on adaptation decisions. As our adaptation decisions considered, such as using sovereign risk financing instruments are associated with a rather short time horizon, the analysis largely focuses on the management of today’s extreme events and does not discuss in detail projections of risks into a future with climate change. Such projections raise important issues of uncertainty, which in some instances may actually render future projections non-robust, a constraint to be kept in mind when addressing longer term decisions, which at the same time should account for both climate and also socioeconomic change.