Areas In Flanders Research Articles

Use of Earth observation for monitoring soil sealing trends in Flanders and Brussels between 1976 and 2013

The on-going growth of urban area in Flanders and in the Brussels Capital Region over the past decades has resulted in a highly sprawled urban tissue, consisting of large and smaller urban agglomerations, connected by a well-developed transportation network. The conversion of open land to urban area is accompanied by an increase in soil sealing, affecting the hydrological cycle and the urban climate. Despite a growing interest in monitoring the process of soil sealing in urban areas, to date no detailed information on the presence and evolution of sealed surfaces is available for Flanders. In this paper a linear regression unmixing approach is proposed to map and monitor changes of sealed surface cover at the regional scale, using medium as well as high resolution remote sensing data. Applied to Flanders and the Brussels Capital Region, a total sealed area of 2687 km² for 2013 is found, corresponding to an increase of 82% since 1976. Residential areas account for nearly half of the sealed area and show the largest increase in sealed surface cover over the past 37 years.

Assessment of estrogenic and androgenic activity in PM10 air samples from an urban, industrial and rural area in Flanders (Belgium) using the CALUX bioassay

BackgroundEndocrine disrupting chemicals represent a broad class of compounds, are widespread in the environment and can pose severe health effects. ObjectivesThe objective of this study was to investigate and compare the overall estrogen and androgen activating potential of PM10 air samples at an urban, rural and industrial location in Flanders, using a human in vitro cell bioassay. MethodsPM10 samples were collected on glass fiber filters every six days between April 2013 and January 2014 using a high-volume sampler. Extraction was executed with a hexane/acetone mixture before analysis using a recombinant estrogen- or androgen responsive human carcinoma cell line. Results were expressed as bioanalytical equivalents (BEQs) per cubic meter of air. ResultsHigh fluctuations in estrogenic activity were observed during the entire sampling period, with median BEQs of 32.1, 35.9 and 31.1 fg E2-Eq m−³ in the industrial, urban and rural background area, respectively. Estrogenic activity was measured in 70% of the samples, while no androgenic activity was observed in any of the samples. The estrogenic activity in the industrial area was positively correlated with the airborne concentration of the sum of the non-carcinogenic PAHs pyrene and fluoranthene (rho=0.48; p<0.01) and the sum of the carcinogenic PAHs (rho=0.36; p=0.05). ConclusionsThis study showed that no androgenic activity was present in PM10 and that although the median estrogenic activity was rather low and comparable in the three locations, high fluctuations in estrogenic response exist over time. While atmospheric PAHs contributed to the observed estrogenic response, especially in the industrial area, the chemicals responsible for the majority of estrogenic activity remain to be identified.

Results of forensic assertive community treatment in Belgium after 33 months

IntroductionForensic adaptations of assertive community treatment (ACT) remain understudied in Europe, whereas promising results emerge from the United States. There is a need for research into the effectiveness of ForACT outside the United States, as Europe differs greatly in terms of organisation of mental health and judicial system.ObjectiveInvestigating effectiveness of forensic adaptations of ACT in the area of Flanders, Belgium. Outcome measures are divided into forensic, like arrests or incarcerations, and non-forensic, like admissions and length of stay.AimsInvestigating effectiveness of ForACT on forensic and non-forensic outcome measures as well as factors related to outcome. A third outcome is community tenure, which is the actual number of days divided by the potential number of days spent in the community.MethodsA controlled cohort study was designed over with first results at 33 months. The experimental group consists of a new ForACT team in the area of Flanders, Belgium (n = 70). Patients are admitted from prison, psychiatric hospitals or other community-based care. The control group consists of mentally ill offenders in community-based treatment after release from prison (n = 56).ResultsResults on forensic measures and community tenure are promising in favour of the ForACT team. In contrast, clients are often, though shortly, readmitted into psychiatric residential care. Substance use emerges as the main reason for admissions.ConclusionsA local forensic adaptation of ACT reveals promising results on forensic outcome measures, yet suffers a large number of admissions.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Presence and trends of linear sprawl: Explaining ribbon development in the north of Belgium

In this paper, we propose a method to analyze ribbon development outside settlements and urban areas in Flanders (Belgium). Based on available statistics, three research hypotheses are tested, which are aimed at giving more insight in the presence and growth rate of ribbon density. From a historical perspective, we can say that an important part of the present ribbons is rooted in previously existing patterns, and that especially in the eighteenth and nineteenth centuries the phenomenon mainly developed in those areas where ribbon development was already considerably present. From an agglomeration effects perspective, however, we note that ribbon development is most prevalent in the most urbanized areas, with the fastest growth rates also observed in these areas. Therefore, today ribbon development is still one of the important morphologies in which urbanization processes materialize. Finally, from a policy perspective, we find that the introduction of spatial policies by means of the regional zoning plans has strongly determined the locations where ribbons could further develop, as well as the growth rate of these ribbons. Since in the most recent period we find significant differences in growth rate between the various zoning districts, the political decision-making processes that underlay the plans prove to have been of great importance for the most recent and future development of ribbons.

Putting domestic gardens on the agenda using empirical spatial data: The case of Flanders

Spatial data are considered to be an essential entry point to get domestic gardens on the agendas of land use monitoring, spatial planning and environmental policies. As a green facet of urbanization, gardens cover a substantial part of land all over the world. Moreover, domestic gardens deliver several ecosystem services. The sustainability turn in planning however focuses on densification. In densification scenarios, planners could consider domestic garden area as a land reserve. Yet, due to a lack of data they would be ill-informed on the domestic garden services and potentials and not be able to make well-founded choices. So, the strategic value of domestic gardens remains largely unquestioned. By developing and applying a mixed methodology that combines an existing land use map with empirical data, this study provides data and insights on the spatial coverage, distribution and growth of domestic garden area in Flanders (the northern region of Belgium). The results show that 8% of the Flemish area is covered by domestic gardens, as well as 21% of the total area of Flemish residential cores. The highest concentrations are found in peri-urban areas and around ribbon developments. About 8% of the garden area that existed in the period 2002–2005 was new compared to the period 1988–1990 and occupied mainly former agricultural land (90%). The results clarify the regional significance of domestic gardens in terms of spatial coverage. The developed mixed methodology made the domestic garden theme analysable. The insights offer an entry point for a debate on the strategic value of domestic gardens.

Determination of PCDD/Fs, PBDD/Fs and dioxin-like PCBs in human milk from mothers residing in the rural areas in Flanders, using the CALUX bioassay and GC-HRMS

Since the CALUX (Chemically Activated LUciferase gene eXpression) bioassay is a fast and inexpensive tool for the determination of dioxin-like compounds in a large number of samples and requires only small sample volumes, the use of this technique in human biomonitoring programs provides a good alternative to GC-HRMS. In this study, a new CALUX method for the separate analysis of PCDD/Fs and dioxin-like PCBs (dl-PCBs) in small amounts of human milk samples with the new sensitive H1L7.5c1 cell line was used to analyze 84 human milk samples, collected from mothers residing in the Flemish rural communities. The geometric mean CALUX-Bioanalytical Equivalent (CALUX-BEQ) values, reported for the 84 mothers from the study area were 10.4 (95% CI: 9.4–11.4) pg CALUX-BEQ per gram lipid or 0.41 (95% CI: 0.37–0.45) pg CALUX-BEQ per gram milk for the PCDD/Fs and 1.73 (1.57–1.91) pg CALUX-BEQ per gram lipid or 0.07 (95% CI: 0.06–0.08) pg CALUX-BEQ per gram milk for the dioxin-like PCBs. Multiple regression analysis showed significant associations between PCDD/Fs and weight change after pregnancy, smoking and consumption of local eggs. One pooled human milk sample was analyzed with both CALUX and GC-HRMS. The ratio of CALUX and GC-HRMS results for this sample were respectively 1.60, 0.58 and 1.23 for the PCDD/Fs, the dl-PCBs and the sum of both fractions, when using the 2005-TEF values. Additionally, also low levels of certain brominated dioxins and furans were detected in the pooled sample with GC-HRMS.

Metal Contaminated Dredged Sediment Derived Soils: A Case Of Diffuse Contamination

Significant areas in Flanders, Belgium exhibit moderate contamination with trace metals caused by deposition or disposal of contaminated 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 was investigated. 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. A comprehensive knowledge of metal behaviour in these sites is essential for developing appropriate management options for these sites.

Persistent organic pollutants (POPs) in human milk: A biomonitoring study in rural areas of Flanders (Belgium)

To collect information on the concentrations of persistent organic pollutants (POPs) in the rural areas in Flanders (Belgium), 84 breastfeeding mothers were recruited in rural communities in East and West Flanders and Flemish Brabant in 2009–2010. Polychlorinated biphenyl (PCB) congeners, organochlorine pesticides, brominated flame retardants, perfluorinated compounds, polychlorinated dibenzodioxines and dibenzofurans, and dioxin-like PCBs were measured in individual milk samples and in a pooled milk sample, while some additional pollutants were only measured in the pooled sample. For most pollutants, the concentrations in this study were lower or comparable to the concentrations measured in the pooled Belgian sample of the WHO human milk study of 2006, except for the pesticides dichlorodiphenyltrichloroethane DDT (+25% for ΣDDT and metabolites) and trans-nonachlor (+94%), and for the brominated flame retardant hexachlorocyclododecane HBCD (+153%). Perfluorinated compounds were for the first time determined in human milk samples from Belgium and the concentrations were comparable to those from other European countries. Also, interesting associations were found between the concentrations of POPs measured in human milk and personal characteristics as well as dietary habits of the study population. PFOS en PFOA concentrations were significantly higher in milk of primiparous participants compared to mothers who gave birth to their second child. Lower brominated PBDE congeners increased with increasing BMI of the mothers (p=0.01 for BDE 47, p=0.02 for BDE 99 and p=0.02 for BDE 100). Participants consuming milk or dairy products daily had significant higher concentrations of ΣDDTs (p=0.03) and oxychlordane (p=0.047) in their human milk samples.

Hormone levels and sexual development in Flemish adolescents residing in areas differing in pollution pressure

In 2002, the Centre for Environment and Health in Flanders, Belgium started a human biomonitoring program. For 1679 adolescents, residing in nine study areas with differing pollution pressure, hormone levels and the degree of sexual maturation were measured. Possible confounding effects of lifestyle and personal characteristics were taken into account. Participants from the nine different study areas had significantly different levels of sex hormones (total and free testosterone, oestradiol, aromatase, luteinizing hormone) and the thyroid hormone free triiodothyronine, after correction for confounders. Significantly higher hormone concentrations were measured in samples from participants residing in the area around the waste incinerators, while significantly lower values were found in participants residing in the Albert Canal zone with chemical industry. Sexual maturation of boys as well as girls tended to be somewhat slower in the industrial city of Antwerp and in the Antwerp harbour compared to the other areas in Flanders. Even within the same study area, significant differences in hormone levels could be observed between sub-areas. Data on the internal exposure of the same adolescents to lead, cadmium, PCBs, p,p'-DDE, HCB, 1-hydroxypyrene and t,t'-muconic acid have already been published. The observed differences in hormone levels and in sexual maturation could however only in part be explained by the measured differences in internal exposure to pollutants, suggesting that also other pollutants and other factors that vary in function of the area of residence could play a role. Nevertheless, our results also suggest that local (environmental) factors, acting within a short distance, might influence the measured hormone levels and degree of sexual maturation.

Multi-Layered Structure and Market Function of the 15th Century Flanders Grain Circulation

In Flanders long-distance grain trade was very developed and unifi cation of the grain market also progressed in the 15th century. A multilayered structure of grain circulation enabled such a situation. The supply of grain was carried out in a multilayered form in Flanders; grain came mainly from surrounding areas of the city, a specifi ed grain production area in Flanders, north France, and the Baltic area. This multilayered structure brought stability in the circulation. Privileged institutions and regulations on grain circulation had developed in close relation with this multilayered circulation structure. In this way, grain supply in Flanders kept its stability in sensitive balance among many elements.1)

SURVEY ON SYMPTOM EXPRESSION AND DAMAGE CAUSED BY PEPINO MOSAIC VIRUS IN COMMERCIAL TOMATO PRODUCTION IN BELGIUM

SURVEY ON SYMPTOM EXPRESSION AND DAMAGE CAUSED BY PEPINO MOSAIC VIRUS IN COMMERCIAL TOMATO PRODUCTION IN BELGIUM

Concentrations in bird feathers reflect regional contamination with organic pollutants

Feathers have recently been shown to be potentially useful non-destructive biomonitoring tools for organic pollutants. However, the suitability of feathers to monitor regional variations in contamination has not been investigated until now. Here concentrations of organic pollutants were compared in feathers of common magpies ( Pica pica) between urban and rural areas in Flanders, Belgium. The results showed that concentrations of p,p' -dichlorodiphenyldichloroethylene (DDE) were significantly higher in the rural areas (rural: 12–140 ng/g feather, urban: 1.1–7.2 ng/g feather), while polychlorinated biphenyls (PCBs) were significantly more available in an urban environment (sum PCBs — rural: 2.9–22 ng/g feather, urban: 41–240 ng/g feather). This pattern agrees with previous studies using other tissues than feathers as a biomonitoring tool. In addition, differences in PCBs and PBDEs profiles were found with lower halogenated congeners being more prominent in the urban areas in comparison to the rural areas. In summary, feathers seem to reflect regional variations in contamination, which strengthens their usefulness as a non-destructive biomonitor for organic pollutants.

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.

Feasibility of isolation perimeters for genetically modified maize

Using geographic information system datasets and Monte Carlo simulations, this study investigates to what extent the intra-regional variability in maize share and field distribution affects the feasibility of implementing isolation perimeters between genetically modified (GM) and non-GM maize fields. More specifically, five scenarios differing in shares and spatial distributions of GM maize were tested for various isolation perimeters in six agricultural areas in Flanders (Belgium). Proportions of non-GM maize fields and farmers having at least one non-GM maize field occurring within isolation perimeters were calculated to assess how spatial co-existence measures would affect the freedom of choice of neighbouring farmers to grow non-GM maize on their fields. Irrespective of the scenario tested, our results demonstrated that the proportions of non-GM maize fields and their corresponding farmers falling within the isolation perimeters are approximately two to eight times higher in areas with the highest maize share than in areas with the lowest maize share. The higher the share of GM maize and the wider the imposed isolation perimeter, the lower the intra-regional differences became. Hence, those findings confirm that farmers will not be equally affected by isolation perimeters, indicating the importance of considering intra-regional differences in the choice of appropriate spatial co-existence measures. Since uniform and wide isolation perimeters tend to be difficult to implement in practice and hardly reflect the diversity of the agricultural landscape, relying on flexible or combining various co-existence measures is worthwhile considering. As an alternative to single co-existence measures for limiting the GM input from cross-fertilisations between neighbouring maize fields, the appropriateness of other on-farm co-existence measures is discussed for Flemish agricultural conditions. Proposing the most appropriate co-existence measures on a case-by-case basis may be one step forward in reaching proportionate, fair and consistent co-existence at the regional and landscape level.

A comparative analysis of cladoceran communities from different water body types: patterns in community composition and diversity

To develop strategies for the management and protection of aquatic biodiversity in water bodies at the landscape scale, there is a need for information on the spatial organization of diversity in different types of aquatic habitats. In this study, we compared the cladoceran composition and diversity between wheel tracks, pools, ponds, lakes, ditches, and streams, in 18 different areas of Flanders (Belgium). Multivariate analysis revealed significant differences in the composition of cladoceran communities among the different water body types. Average local and total diversity tended to be highest for lakes and lowest for streams. Despite the relatively high number of species supported by lakes, small water bodies seem to contribute considerably more to the total cladoceran richness of an average landscape in Flanders than lakes, because of their high abundance. With respect to biodiversity conservation at the landscape scale, our results point to the importance of maintaining a diversity of water body types of different size, permanence and flow regimes.

Parental smoking behavior and caries experience in preschool children

The study aimed to explore the association between parental smoking behavior and caries experience in young children, taking into account the socioeconomic status and oral health-related behavior. Cross-sectional data from 1250 3-year-old and 1283 5-year-old children from four geographical areas in Flanders (Belgium) were analyzed. Children were examined at school by trained dentist-examiners, using standard criteria and calibrated examination methodology. Data on oral hygiene and dietary habits, oral health behavior, sociodemographic variables, and parental smoking behavior were obtained through structured questionnaires, completed by the parents. Visible caries experience (i.e. d(3)mft > 0) was seen in 7% of 3-year olds and 31% of 5-year olds. In both age groups, 30% of the parents reported smoking behavior. Univariable logistic regression analysis with caries prevalence as the dependent variable, revealed that parental smoking was a significant independent variable. After controlling for age, gender, sociodemographic characteristics, oral hygiene, and dietary habits, the effect of family smoking status was no longer significant in 3-year-old children (OR = 1.98; 95% CI: 0.68-5.76). In 5-year olds the significant relationship between parental smoking behavior and caries experience persisted after adjusting for the other evaluated variables (OR = 3.36; 95% CI: 1.49-7.58). The results of this study illustrate the existence of a significant association between parental smoking behavior and caries experience in 5-year-old children.

Implementing isolation perimeters around genetically modified maize fields

Due to the growing cultivation area of genetically modified (GM) maize and the rising number of GM maize varieties commercially available to European farmers, the co-existence between GM and non-GM maize is becoming a burning issue in some European regions. Hence, Member States are imposing or discussing specific co-existence measures to keep the adventitious presence of GM material in non-GM produces below the established labelling threshold. As maize is a cross-pollinated crop that uses wind for the dispersal of its pollen, on-farm co-existence measures may rely on the spatial isolation of GM and non-GM maize fields. In this study, we developed an approach that combines geographic information system (GIS) datasets with Monte Carlo simulations to assess the feasibility of implementing isolation perimeters around GM maize fields, since its practical implementation is rarely addressed in the co-existence debate. More specifically, five scenarios differing in shares and spatial distributions of GM maize were tested for various isolation perimeters in two agricultural areas in Flanders (Belgium). The GIS analyses emphasised the small size of maize fields and their scattered distribution throughout the cropped area. The feasibility of implementing isolation perimeters was largely affected by the (GM) maize share, the spatial distribution of GM maize, and the width of isolation perimeters. The higher the (GM) maize share and the wider the isolation perimeter, the higher the proportions of farmers with non-GM maize fields occurring within the implemented isolation perimeter. Compared with randomly distributed GM maize fields, the clustering of GM maize fields on a larger scale and at the farm level increased the feasibility of implementing isolation perimeters. The approach developed proved to be a valuable tool to quantify the feasibility of implementing isolation perimeters under real agricultural conditions.

Factors associated with prevalence and severity of caries experience in preschool children

The aim of the present study was to examine the prevalence and severity of caries experience in the primary dentition of preschool children and to assess the association of disease distribution with oral hygiene levels, reported oral health behaviours and socio-demographic factors. Study samples comprised 1250 3-year-old and 1283 5-year-old pre-school children from four distinct geographical areas in Flanders. Information on oral hygiene and dietary habits, oral health behaviours and socio-demographic variables was collected using questionnaires completed by the parents. Clinical examinations were performed using standardized criteria. Caries experience was recorded at the level of cavitation (d(3) level). Simple as well as multivariable logistic regression analyses were performed in order to identify factors associated with prevalence and severity of caries experience. Visible plaque was present in 31% of 3-year-olds and 37% of 5-year-olds. In 3-year-olds, 7% presented with caries experience while this was the case in 31% of 5-year-olds. Multivariable logistic regression revealed significant associations, in 3-year-olds, of caries experience with presence of dental plaque (OR = 7.93; 95% CI: 2.56-24.55) and reported consumption of sugared drinks at night (OR = 7.96; 95% CI: 1.57-40.51). In 5-year-olds, significant associations were seen with age (OR = 7.79; 95% CI: 2.38-25.43), gender (OR = 0.37 with 95% CI: 0.19-0.71 for girls), presence of visible dental plaque (OR = 3.36; 95% CI: 1.64-6.89) and reported habit of having sugar-containing drinks in between meals (OR = 2.60 with 95% CI: 1.16-5.84 and OR = 3.18 with 95% CI: 1.39-7.28, respectively for 1x/day and > 1x/day versus not every day). In 5-year-olds with caries experience (30.8% of total sample), the severity of disease was further analysed (d(3)mft between 1 and 4 versus d(3)mft 5 or higher). Multivariable analyses showed a significant association with gender [girls more likely to have higher disease levels; OR = 4.67 (95% CI: 1.65-13.21)] and with presence of plaque (OR = 3.91 with 95% CI: 1.23-12.42). Presence of visible plaque accumulation and reported consumption of sugared drinks were associated with prevalence of caries experience in Flemish preschool children. Severity of disease was associated with gender and with presence of plaque. Results underline the importance of plaque control and diet management from very young age on.

Motor vehicles as vectors of plant species from road verges in a suburban environment

The objective of this study was to assess the potential contribution of car-borne flora to species dispersal in a suburban area in Flanders (Belgium). Therefore, motor vehicle-borne flora was evaluated monthly for a random sample of 20 cars between October 1988 and September 1989. At the end of the experiment 33 car-borne plant species, with a total of 690 seedlings were identified from mud, attached to these vehicles. There was considerable temporal variation in the mud mass attached to the vehicles and therefore also the size and composition of the vehicle-borne flora varied during the year. Because mud retention on cars is a crucial factor in seed dispersal, the number of emerging seedlings is negatively correlated with precipitation in the week preceding the sampling. The flora dispersed by vehicles consists mostly of species with small, light seeds and a persistent seed bank. Usually, they are pioneer species of nitrogen-rich habitats. The nature of the vehicle dispersed flora was compared with the local flora of road verges and differed significantly from this in, e.g., seed length, seed weight, ecological groups, Ellenberg indicator values for nitrogen supply, potential dispersal strategies and rarity. A larger resemblance with the flora of the zone immediately adjacent to the carriageway was found. We only found a low similarity to other motor vehicle-borne floras. Die Zielsetzung dieser Untersuchung war es den potenziellen Beitrag der von Autos verbreiteten Flora an der Artausbreitung in einem Vorstadtgebiet in Flandern (Belgien) abzuschätzen. Deshalb wurde monatlich die Flora, die von Motorfahrzeugen getragen wird, für eine Zufallsprobe von 20 Autos zwischen Oktober 1988 und September 1989 ausgewertet. Am Ende des Experiments wurden 33 Pflanzenarten, die von Autos getragen werden, mit insgesamt 690 Keimlingen aus dem Schlamm identifiziert, der an diesen Fahrzeugen haftete. Es gab eine beträchtliche zeitliche Variation in der Schlammmenge, die den Fahrzeugen anhaftete, und deshalb variierte die Größe und Zusammensetzung der von Autos getragenen Flora ebenso über das Jahr. Weil die Rückhaltung des Schlamms an den Autos ein ausschlaggebender Faktor für die Samenverbreitung ist, ist die Anzahl der jungen Keimlinge negativ mit dem Niederschlag der Woche korreliert, die der Probenahme voranging. Die Flora, die über Fahrzeuge verbreitet wird, besteht vor allem aus Arten mit kleinen, leichten Samen und einer langlebigen Samenbank. Normalerweise sind sie Pionierarten der stickstoffreichen Habitate. Die Natur der fahrzeugverbreiteten Flora wurde mit der lokalen Flora der Straßenränder verglichen und unterschied sich signifikant von ihr, beispielsweise in der Samenlänge, im Samengewicht, in den ökologischen Gruppen, in den Ellebergschen Zeigerwerten für Stickstoffversorgung, in den potenziellen Verbreitungsstrategien und in der Seltenheit. Eine größere Ähnlichkeit wurde zur Flora der Zone gefunden, die unmittelbar an die Fahrbahn grenzt. Wir fanden nur eine geringe Ähnlichkeit mit anderen Floren, die von Motorfahrzeugen verbreitet werden.

Genotoxicity of PM 10 and extracted organics collected in an industrial, urban and rural area in Flanders, Belgium

The variation in the genotoxic potency of PM 10 in vitro in relation to the particle source type was investigated. Particles were collected at one urban, one rural, and one industrial site in Flanders. Genotoxicity was assessed using four different in vitro test systems exposed to PM 10 in suspension and to the organic extracts of PM 10. Two of these systems were bacterial assays: the Salmonella mutagenicity test and the Vitotox test. In addition, the Comet assay and Micronucleus test were performed using human blood cells. Results show that exposure to PM 10 and the organic extracts from both urban and industrial areas causes significant genetic damage. The Salmonella mutagenicity test was most suitable for the screening of PM 10 and the organic extracts; the Micronucleus test was most suitable only for the screening of organic extracts, and original particles were toxic for the exposed lymphocytes. Clear dose–response curves were not established in the Comet and Vitotox assay, and organic extracts were apparently toxic in the latter. The total polycyclic aromatic hydrocarbon content of the organic extracts, as measured with GC/MS, ranged between 1 and 6 ng/m 3. Results obtained in this study suggest that PM 10 causes DNA damage and mutations. The use of biological tests for the screening of air samples is useful to complement air quality control by chemical measurements.