Cycling and ecosystem impact of metals in contaminated calcareous dredged sediment-derived soils (Flanders, Belgium)

Significant areas in Flanders, Belgium exhibit moderate contamination with trace metals caused by disposal of contaminated dredged sediments. After disposal, the sediments develop into a soil-like material, on which vegetation is planted or develops spontaneously. Behaviour, cycling and ecosystem impacts of trace metals in calcareous dredged sediment disposal sites in Flanders is reviewed. Although soil physico-chemical properties favour a low metal bioavailability, pore water concentrations can be elevated compared to pore water in uncontaminated soils. While metal leaching is not considered to be of concern, several plants accumulate elevated levels of Cd and Zn in leaves. Also metal levels in soil dwelling organisms and small mammals, particularly Cd, are elevated compared to reference situations. This raises concern for an enhanced transfer of metals to the food chain. Future research should identify biological effects on organisms caused by the contamination. A comprehensive knowledge of metal behaviour in these sites is essential for developing appropriate management options for these sites.     

Calculation and mapping of critical loads of sulfur and nitrogen in Flanders, Belgium

Up to now, critical loads calculations for the Flemish Region were based on European background data of surrounding countries. A first attempt has been made to calculate and map critical loads for forest ecosystems in Flanders using available site-specific information. Values of current deposition were used to calculate and map exceedances. The lowest critical loads for acidification (697 eq ha(-1)year(-1)) occur in the Campine and the north of Limburg where ecosystems largely consist of coniferous forests on poor sandy soils. The dominance of coniferous forest types in the Campine is also responsible for low critical load values for eutrophication (between 536 and 971 eq ha(-1)year(-1)). In 75% of the receptor points that have been considered an exceedance of the critical load for acidification is noted, primarily in areas with high SO2 and NOx depositions, such as the north of the provinces East and West Flanders and Antwerp. The critical load for eutrophication is exceeded in all points considered. Exceedances are particularly high in coniferous forests in West Flanders, and in the north of the provinces of Antwerp and Limburg, where especially NHx depositions amount to high values. Data needed for the calculation of critical loads are still sparse in Flanders, e.g. for: (1) weathering rates of soil minerals; (2) interception and evaporation of forest ecosystems; and (3) uptake of N and basic cations by vegetation. This supplementary information will contribute to a further refining of the calculated critical loads, which constitute indispensable information in developing an emission abatement policy.     

Life cycle of buildings,demolition and recycling potential: A case study in Turin,Italy

One of the most challenging issues presently facing policymakers and public administrators in Italy concerns what to do with waste materials from building dismantling activities and to understand whether, and to what extent, the ever-increasing quantity of demolition waste can replace virgin materials. The paper presents the results from a research programme that was focused on the life cycle assessment (LCA) of a residential building, located in Turin, which was demolished in 2004 by controlled blasting. A detailed LCA model was set-up, based on field measured data from an urban area under demolition and re-design, paying attention to the end-of-life phase and supplying actual data on demolition and rubble recycling. The results have demonstrated that, while building waste recycling is economically feasible and profitable, it is also sustainable from the energetic and environmental point of view. Compared to the environmental burdens associated with the materials embodied in the building shell, the recycling potential is 29% and 18% in terms of life cycle energy and greenhouse emissions, respectively. The recycling potential of the main building materials was made available in order to address future demolition projects and supply basic knowledge in the design for dismantling field.     

Radon risk mapping in southern Belgium: an application of geostatistical and GIS techniques

A data set of long-term radon measurements in approximately 2200 houses in southern Belgium has been collected in an on-going national radon survey. The spatial variation of indoor Rn concentrations is modelled by variograms. A radon distribution map is produced using the log-normal kriging technique. A GIS is used to digitise, process and integrate a variety of data, including geological maps, Rn concentrations associated with house locations and an administrative map, etc. It also allows evaluation of the relationships between various spatial data sets with the goal of producing radon risk maps. Based on geostatistical mapping and spatial analysis, we define three categories of risk areas: high risk, medium risk and low risk area. The correlation between radon concentrations and geological features is proved in this study. High and medium Rn risk zones are dominantly situated in bedrock from the Cambrian to Lower Devonian, although a few medium risk zones are within the Jurassic. It is evident that high-risk zones are related to a strongly folded and fractured context.     

On the genesis of an urban policy in Flanders, Belgium

Conclusion Inner-city decay took place gradually over many decades. As a matter of fact, improving the inner city is also a slow process; this goal cannot be achieved within one term of office. The city must regain the trust of the inhabitants. Plans must be drawn up, land and buildings must be purchased, and advisory bodies must be established. This is a complicated matter. Moreover, the rules of the game have changed. That is why the first convenant has great experimental value. Both the framework of the SIF and the convenant must be given a chance to grow. If the dilapidated neighbourhoods do not show improvement yet, and if the confidence of the population is not regained within a three-year period, we can only hope that the baby will not be thrown out with the bathwater. Above all, the urban policy requires stability and continuity if it is to thrive. Bascal de Decker studied sociology and urban planning at the State University of Ghent. He is expert at the Cabinet of the Flemish Minister of Internal Affairs, Urban Policy and Housing, Brussels.     

Housing tenure, housing costs and poverty in Flanders (Belgium)

This article deals with the relation betweenhousing and poverty in Flanders (Belgium). Wedescribe how home tenure and housing costsdeveloped differently for different incomegroups. Furthermore, we assess the impact ofthese evolutions on poverty and welfaredistribution. Our analyses show that in theobserved period homeownership increasedstrongly among higher-income categories andremained stable or even decreased amonglow-income households. Average housing costsincreased more for low-income households thanfor high-income households, leading to a sharpincrease in problematic rent-to-income ratiosfor the former. It appears that especially theprivate rented sector is problematic. Thesocial rented sector is evaluated ratherpositively. Taking account of housing costsleads to higher poverty levels and higherwelfare inequality compared to the situationwhere only current income is used to calculatepoverty and welfare distribution.     

Estimating the groutability of granular soils: a new approach

This paper evaluates different parameters that affect the grouting of soil, and presents a new approach to predict the groutability of granular soil. An accurate prediction of the groutability of granular soils has always been complicated due to the effects of different soil parameters. We know that these parameters are the grain-size of soil and cement-based grouts, the relative density and fine contents of soil, the water/cement ratio of grout mixture and grouting pressure, which directly affect the groutability of soil media. However, the relative density, fine contents of soil, the water/cement ratio, and grouting pressure are seldom considered as the prediction of groutability. In order to study the effects of the parameters on groutability, an alternative empirical formula to estimate the groutability of granular soils is presented in this paper and supported by experimental results obtained from the grouted sand samples prepared with various relative densities. The newly developed approach will help for the more accurate prediction of the groutability in granular soils and may also be used to provide first-hand information about the groutability of soils.     

Freeze-thaw resistance of stabilized soils in Flanders

Clayey and loamy soils, in Flanders, are improved with a wide range of stabilizing products. This paper reports an investigation into the impact of 12 freeze-thaw cycles on the mechanical properties of stabilized soils. Results indicate that freeze-thaw cycles reduce the unconfined compressive strength of all the test specimens by 10%. A weak stabilized material, with a small compressive strength, has a great material loss and a big drop in compressive strength. In this study, the various stabilized test pieces do not undergo volume change after eight cycles. The water content of all test pieces decreases, until equilibrium between forward and reverse water migration.     

Towards a sustainable transformation of the detached houses in peri-urban Flanders,Belgium

This article explores possibilities for future uses of inflatable and fabric architecture in urban contexts. Such uses may serve regeneration or homeless sheltering purposes, drawing from the Bedouin and Traveller traditions. They may also build on the much more recent Western precedents offered by the “Occupy” movement and pop-up buildings, and arguably follow in the footsteps of Situationism.     

Place Attachment Among Older Adults Living in Four Communities in Flanders,Belgium

There is strong evidence that age brings an increasing attachment to social and physical environments. However, the extent to which the experience of place attachment may vary between different types of locations remains underexplored in ageing research. Using a mixed-method approach consisting of two consecutive phases, this article aims to identify contextual factors that either promote or impede older people's attachment to place. In the first phase, quantitative data from the Belgian Ageing Studies were used to purposively select four municipalities: two with relatively strong and two with relatively weak place attachments among the older population. In the second, qualitative phase, two focus groups with local stakeholders and 20 semi-structured interviews with older residents were conducted in each of the four case study areas in order to explain and build on the quantitative results. The qualitative findings focus on two contextual factors that have been linked to place attachment: the physical–spatial environment and population turnover. The study identifies the various pathways between these factors and older people's attachments. The article concludes by discussing practical and policy issues raised by the research.     

The creation of the incapable social tenant in Flanders,Belgium. An appraisal

As long as the social rented sector housed traditional families and the allocation procedures were rather loose, there was little commotion about the sector. A combination of a change in family structures, economic changes, and the strengthening of allocation procedures in favour of those most in need did change perceptions. Marginalisation and ghettoisation, especially of high-rise social housing estates, became buzzwords. This paper deals with the causes of these changes and with their implications. The marginalisation discourse calls for enlarging the target groups and estate-specific allocation procedures (to obtain a `social mix'). It illustrates a profound desire to diminish the number of ethnic minorities, single parents, single-person households and all kinds of people with a weak income profile who gain access to social rental housing. Furthermore, this discourse is reaching a crescendo: after it was started in the early 1990s by staff members of local social housing companies, it passed through the union of the social housing companies, the umbrella organisation of the sector, and parliament, reaching its greatest momentum so far in early 2002 when it was adopted by the Flemish housing minister. The counterpoint to this negative discourse is the high degree of satisfaction among social tenants, as observed in a study carried out in 1999. In our paper we will try to explain the background of these opposing trends and the possible consequences for the social rental housing in general and for tenants in particular.     

Geographies of whiteness and wealth: White,middle class discourses on segregation and social mix in Flanders,Belgium

While policy makers in different parts of the world are worried about the supposedly negative consequences of spatial concentrations of ethnic minorities and/or disadvantaged people, researchers continue the debate about the desirability and feasibility of social mix. In this article, we add to this literature by focusing on the often neglected, but crucial practices and discourses of the privileged in urban and suburban neighborhoods. Drawing on in‐depth interviews with 74 white, middle class residents of eight different neighborhoods of the Ghent urban region in Belgium, we demonstrate that few middle class whites actually want to live in a mixed neighborhood. We also make it clear that those living in diversity do not necessarily take up the roles they are expected to take up by the advocates of social mix policies. Drawing on these findings, we propose to broaden the research agenda of studies on segregation and social mix.     

From SIF to City Fund: a new direction for urban policy in Flanders,Belgium

For years, analysts have wondered about the exceptional place that Belgium, and in particular Flanders, has taken in the urban policy landscape. Contrary to neighbouring, equally strongly urbanised Western European countries, Flanders maintained a tradition of neglect towards its urban centres, linked to the hegemony of a rural-based Christian-democratic party. In the 1990’s, this tradition was converted into an urban policy approach which, equally at odds with developments towards urban entrepreneurialism in other Western European countries, remained strongly oriented towards social policy. Only in 1999, when, for the first time in 50 years Christian-democrats resigned from government, the Flemish discourse took a more pro-urban and entrepreneurial approach. This paper shows how this discursive shift at the regional scale is reflected in local urban policy-making practices and warns against the detrimental social effects it might have on the field.

Chaotic,fluid and unstable: an exploration of the complex housing trajectories of homeless people in Flanders,Belgium

This article analyses the housing and homeless pathways of (ex)homeless persons in the coastal city of Ostend. After a short review of the literature on the causes and meaning of the vulnerability of homeless persons, we describe how our case study with (former) homeless persons in Ostend was organised. We deal with some methodological issues and the analytic results, revealing a very complex housing trajectory. We focus on these dynamic and complex housing pathways and look at the role of relationships and relationship breakdown, work and unemployment, eviction after rent arrears and moving as an escape strategy. We also deal with the searching process for housing and the role of social networks. We end with some conclusions and interest points for policy.     

Accumulation of metals in a horizontal subsurface flow constructed wetland treating domestic wastewater in Flanders, Belgium

This study assessed the accumulation of metals in a horizontal subsurface flow constructed wetland treating domestic wastewater of 350 PE after three years of operation. Metal concentrations in the influent wastewater, effluent, sediment, leaves, stems, and belowground biomass of Phragmites australis were analysed. Spatial variations were assessed by sampling at increasing distance from the inlet and at different positions across the width of the reed bed. All metals except Fe and Mn were efficiently removed in the CW, total metal concentrations in the effluent complied with basic environmental quality standards for surface water, and dissolved metal concentrations were often lower than analytical detection limits. Removal efficiencies varied between 49% for Ni and 93% for Al. Export of dissolved Mn and particulate Fe occurred, probably related to redox conditions in the sediment. After 3 years of operation, the sediment in the inlet area was significantly contaminated with Zn, Cu, and Cd, whereas Pb could form a contamination problem within the near future. The Cr and Ni levels in the sediment were low throughout the entire reed bed. At this stage of operation, the contamination problem was still situated within the inlet area and metal concentrations in the sediment decreased towards background values further along the treatment path. An exponential decrease of the metal mass in the sediment and belowground biomass was seen for all metals except Mn. Contrary to the other metals, Mn concentrations in the sediment increased with distance. For all metals, less than 2% of the mass removed from the wastewater after passage through the reed bed is accumulated in the aboveground reed biomass. The sediment acts as the primary sink for metals.     

水泥搅拌桩浆喷法在道路软基处理中的应用——厦门市海沧出口加工区六号路软基处理实例

厦门市海沧加工区六号路工程所在地原始地貌单元为滨海滩涂地 ,地基为淤泥及粘性土。本文对各种地基处理措施进行了分析比较 ,采用了水泥搅拌桩处理方式。解决了软弱基处理的系列问题 ,并提出几点建议     

Trace elements in home-produced eggs in Belgium: Levels and spatiotemporal distribution

The purpose of this study was to evaluate the levels of arsenic, cadmium, lead, copper and zinc in home-produced eggs, soils and kitchen waste samples of private chicken owners in Belgium, and to determine spatiotemporal differences in trace element contents in eggs. Eggs were sampled in all provinces of Belgium in autumn 2006 and spring 2007. A total number of 59 private chicken owners participated in the study. Trace elements were determined by inductively coupled plasma-mass spectrometry except for mercury, which was determined by atomic absorption of mercury vapour. The mean fresh weight concentrations in eggs in autumn and spring respectively were < 8.0 and < 8.0 µg/kg for arsenic, 0.5 and < 0.5 µg/kg for cadmium, 116 and 74 µg/kg for lead, 0.43 and 0.52 mg/kg for copper, 20.3 and 19.2 mg/kg for zinc, and 3.15 and 4.44 µg/kg for mercury. Analysis of variance determined significant differences in some trace element concentrations in eggs among seasons and regions in Belgium. Average concentrations of arsenic, cadmium and mercury corresponded well with values measured in other countries, while copper and zinc concentrations were within the same order of magnitude as in other countries. Average lead concentrations were high compared to concentrations in eggs from other countries and correlated well with lead concentrations in soil, indicating that the soil is an important source. Other sources of trace elements in eggs might be home-grown vegetables and forage (grass and herbs), and indirectly, air pollution.     

Evaluation of the process of integration in a transdisciplinary landscape study in the Pajottenland (Flanders, Belgium)

In order to preserve the overall landscape values in the Pajottenland, the province of Vlaams-Brabant initiated a campaign to raise awareness of local authorities and stakeholders and to stimulate co-coordinated actions. As very few scientific studies exist for the region, an interdisciplinary study was commissioned from the University of Ghent, involving archaeologists, historians, geographers and planners. This article evaluates the process of integration between the scientific disciplines and between the researchers (interdisciplinary) and program team and stakeholders (transdisciplinary) involved in this project. Potentials and difficulties encountered in the successive phases are evaluated and discussed. The interdisciplinary trajectory worked relatively smoothly as it was focused upon the realization of the first integrated landscape biography for the region. This biography includes scientific results as well as an integration of the complex legal and administrative instruments, which are necessary for the implementation of the study. Also, a methodology was developed for assessing landscape values at the municipal level, to be carried out by local stakeholders. This methodology was demonstrated with the case study of Gooik. The transdisciplinary integration encountered a series of difficulties, which mainly related to the unclear and shifting objectives of the program team and to aspects of communication between the partners and the lack of a common language.     

PCDD/Fs and dioxin-like PCBs in home-produced eggs from Belgium: Levels, contamination sources and health risks

This paper discusses the dioxin TEQ levels as determined by the chemically activated luciferase gene expression assay (CALUX) and by HRGC-HRMS in eggs, soils, faeces and kitchen waste samples obtained in the CONTEGG study. The samples were collected in each Belgian province at private homes and in small gardens where chickens are held. The CALUX levels for eggs sampled in autumn were higher than the levels in eggs obtained at the same locations in spring (median values of 5.86 and 4.08 pg CALUX TEQ/g fat, respectively). The total WHO-TEQ levels in eggs, determined by HRGC-HRMS, ranged from 3.29 to 95.35 pg TEQ/g fat in autumn and from 1.50 to 64.79 pg TEQ/g fat in spring. In the soils on which the chickens forage, levels of 2.51-11.35 pg I-TEQ/g in autumn and 2.00-7.86 pg I-TEQ/g in spring were found. The congener pattern of PCDD/Fs in the eggs, soils and faeces was dominated by OCDD, in addition to 1,2,3,4,6,7,8-HeptaCDD, OCDF and 1,2,3,4,6,7,8-HeptaCDF. The predominant dioxin-like PCBs were PCB118, PCB 105 and PCB 156. The dioxin-like PCBs contributed on average 47%, 14% and 20% to the total WHO-TEQ in eggs, soils and faeces, respectively. Kitchen waste samples were very low-contaminated with dioxin-like compounds. The present results showed a good agreement between egg and soil TEQ levels for PCDD/Fs but not for dioxin-like PCBs. This study showed that current soil levels found in some private gardens do not lead to egg levels below the current EU maximal level of 6 pg total TEQ/g fat for dioxins and dioxin-like PCBs. The consumers of the analysed eggs attained 5-79% of the tolerable weekly intake (TWI) of 14 pg TEQ/kg bw for dioxins and dioxin-like PCBs by exposure to their home-produced eggs only.     

The soil condition, the foundation and the basement of the Frauenkirche in Dresden

The archeological reconstruction of the Frauenkirche in Dresden was begun immediately following the archeological removal of the rubble of the remains. In this process, four essential construction phases were realized during the time frame from May 1994 until August 1996. To start with, a small section of the wall at the southwest corner of the church was filled in Lot 0. Lot 1 was the realization of a larger wall section at the southwest corner. Further tasks were the renovation of the cellar up to the upper edge of the ground floor and the erection of a subterranean exterior structure. These tasks were preceded by comprehensive activities: review of existing documents (plans, photographs); evaluation of the existing building structure; soil investigations and material tests, preparation of a dimensioned drawing reflecting deformation of the building structure left standing as well as starting deformation measurements of the cellar walls of the ruin as well as of the ruin parts that were left standing. The objective was, in comparison to Bähr's concept, to develop an optimized concept for the support structure. In doing so, solutions had to be found which met the requirements for intended use as specified by the building's owner. The increased demand for space was satisfied with the concept of a subterranean external building, encompassing the church on three sides. One essential item within the scope of structural concept was the elaboration of a secure concept for the reinforcement of the foundations.