• Airway antioxidant and inflammatory responses to diesel exhaust exposure in healthy humans.

      Behndig, A F; Mudway, I S; Brown, J L; Stenfors, N; Helleday, R; Duggan, S T; Wilson, S J; Boman, C; Cassee, Flemming R; Frew, A J; Kelly, F J; Sandström, T; Blomberg, A (2006-02-01)
      Pulmonary cells exposed to diesel exhaust (DE) particles in vitro respond in a hierarchical fashion with protective antioxidant responses predominating at low doses and inflammation and injury only occurring at higher concentrations. In the present study, the authors examined whether similar responses occurred in vivo, specifically whether antioxidants were upregulated following a low-dose DE challenge and investigated how these responses related to the development of airway inflammation at different levels of the respiratory tract where particle dose varies markedly. A total of 15 volunteers were exposed to DE (100 microg x m(-3) airborne particulate matter with a diameter of <10 microm for 2 h) and air in a double-blinded, randomised fashion. At 18 h post-exposure, bronchoscopy was performed with lavage and mucosal biopsies taken to assess airway redox and inflammatory status. Following DE exposure, the current authors observed an increase in bronchial mucosa neutrophil and mast cell numbers, as well as increased neutrophil numbers, interleukin-8 and myeloperoxidase concentrations in bronchial lavage. No inflammatory responses were seen in the alveolar compartment, but both reduced glutathione and urate concentrations were increased following diesel exposure. In conclusion, the lung inflammatory response to diesel exhaust is compartmentalised, related to differing antioxidant responses in the conducting airway and alveolar regions.
    • Allometry, biocomplexity, and web topology of hundred agro-environments in The Netherlands

      Mulder, Christian; Hollander, Henri den; Schouten, Ton; Rutgers, Michiel (2006-07-07)
      For almost all soil organisms, the logarithm of numerical abundance (N) is inversely related to the logarithm of body mass (M). It is helpful to use allometry and food-web topology to condense environmental information. Using mathematical evidence derived from 99 real webs, a hypothesis is formulated to explain how belowground soil organisms become affected by increasing effects of animal manure and this is discussed in relation to soil productivity. As a matter of fact, the intercepts of allometric correlations change in a highly significant way according to aboveground grazing by mammals. Linear regressions of log10(N) values fitted against their log10(M) averages show allometric unity (slopes equal to −1) only in one fourth of the webs. Under different levels of taxonomic aggregation, our intercepts remain directly correlated with macroherbivory. Also after removal of bacteria from these real webs, intercepts of the linear regressions robustly fitted on the eukaryotes’ M and N reflect the local nitrogen availability from animal manure. Other basic web properties, such as trophic links and structural complexity, display a comparable pattern from nutrient-poor to nutrient-rich ecosystems, in contrast to a rather erratic connectance. Regardless of total soil biodiversity, only in 23 real webs a host of organisms ranging from earthworms and insects to bacterial cells seem to interact in ways beneficial to each other.
    • Application of multimedia models for screening assessment of long-range transport potential and overall persistence.

      Klasmeier, Jörg; Matthies, Michael; Macleod, Matthew; Fenner, Kathrin; Scheringer, Martin; Stroebe, Maximilian; Gall, Anne Christine le; McKone, Thomas; Meent, Dik van de; Wania, Frank (2006-01-01)
      We propose a multimedia model-based methodology to evaluate whether a chemical substance qualifies as POP-like based on overall persistence (Pov) and potential for long-range transport (LRTP). It relies upon screening chemicals against the Pov and LRTP characteristics of selected reference chemicals with well-established environmental fates. Results indicate that chemicals of high and low concern in terms of persistence and long-range transport can be consistently identified by eight contemporary multimedia models using the proposed methodology. Model results for three hypothetical chemicals illustrate that the model-based classification of chemicals according to Pov and LRTP is not always consistent with the single-media half-life approach proposed by the UNEP Stockholm Convention and thatthe models provide additional insight into the likely long-term hazards associated with chemicals in the environment. We suggest this model-based classification method be adopted as a complement to screening against defined half-life criteria at the initial stages of tiered assessments designed to identify POP-like chemicals and to prioritize further environmental fate studies for new and existing chemicals.
    • BasinBox: a generic multimedia fate model for predicting the fate of chemicals in river catchments

      Hollander, A; Huijbregts, M A J; Ragas, A M J; Meent, D van de (Springer, 2006-05-20)
      Multimedia fate models have proven to be very useful tools in chemical risk assessment and management. This paper presents BasinBox, a newly developed steady-state generic multimedia fate model for evaluating risks of new and existing chemicals in river basins. The model concepts, as well as the intermedia processes quantified in the model, are outlined, and an overview of the required input parameters is given. To test the BasinBox model, calculations were carried out for predicting the fate of chemicals in the river Rhine basin. This was done for a set of 3175 hypothetical chemicals and three emission scenarios to air, river water and cropland soils. For each of these hypothetical chemicals and emission scenarios the concentration ratio between the downstream area and the upstream area was calculated for all compartments. From these calculations it appeared that BasinBox predicts significant concentration differences between upstream and downstream areas of the Rhine river basin for certain types of chemicals and emission scenarios. There is a clear trend of increasing chemical concentrations in downstream direction of the river basin. The calculations show that taking into account spatial variability between upstream, midstream and downstream areas of large river basins can be useful in the predictions of environmental concentrations by multimedia fate models.
    • Bescherming ozonlaag : 20 jaar effectief beleid - een welkome waarheid

      KNMI; MNP; RIVM (Koninklijk Nederlands Meteorologisch Instituut (KNMI), Milieu- en Natuurplanbureau (MNP),, 2007-09)
    • Comparison of analytical techniques for dynamic trace metal speciation in natural freshwaters.

      Sigg, Laura; Black, Frank; Buffle, Jacques; Cao, Jun; Cleven, Rob; Davison, William; Galceran, Josep; Gunkel, Peggy; Kalis, Erwin; Kistler, David; Martin, Michel; Noël, Stéphane; Nur, Yusuf; Odzak, Niksa; Puy, Jaume; Riemsdijk, Willem van; Temminghoff, Erwin; Tercier-Waeber, Mary-Lou; Toepperwien, Stefanie; Town, Raewyn M; Unsworth, Emily R; Warnken, Kent W; Weng, Liping; Xue, Hanbin; Zhang, Hao (2006-03-15)
      Several techniques for speciation analysis of Cu, Zn, Cd, Pb, and Ni are used in freshwater systems and compared with respect to their performance and to the metal species detected. The analytical techniques comprise the following: (i) diffusion gradients in thin-film gels (DGT); (ii) gel integrated microelectrodes combined to voltammetric in situ profiling system (GIME-VIP); (iii) stripping chronopotentiometry (SCP); (iv) flow-through and hollow fiber permeation liquid membranes (FTPLM and HFPLM); (v) Donnan membrane technique (DMT); (vi) competitive ligand-exchange/stripping voltammetry (CLE-SV). All methods could be used both under hardwater and under softwater conditions, although in some cases problems with detection limits were encountered at the low total concentrations. The detected Cu, Cd, and Pb concentrations decreased in the order DGT > or = GIME-VIP > or = FTPLM > or = HFPLM approximately = DMT (>CLE-SV for Cd), detected Zn decreased as DGT > or = GIME-VIP and Ni as DGT > DMT, in agreement with the known dynamic features of these techniques. Techniques involving in situ measurements (GIME-VIP) or in situ exposure (DGT, DMT, and HFPLM) appear to be appropriate in avoiding artifacts which may occur during sampling and sample handling.
    • Copper in the terrestrial environment: Verification of a laboratory-derived terrestrial biotic ligand model to predict earthworm mortality with toxicity observed in field soils

      Koster, Marijke; Groot, Arthur de; Vijver, Martina G; Peijnenburg, Willie J G M (Elsevier, 2006-02-21)
      This study was set up for validation of a regression model to predict mortality in the terrestrial earthworm Aporrectodea caliginosa following exposure to copper. This model was derived from a terrestrial biotic ligand model and incorporates the protective effects of H+ and Na+ on copper toxicity. Three soil sets were used for the experiments, all of which had a different copper contamination history over more than 20 years and were considered to be aged field soils. The soils were characterized by analysis of various copper pools in the solid phase and in the pore water, analysis of physical and chemical soil properties and by regression analysis. Measured and calculated copper activities (expressed as pCu) correlated reasonably well. Measured copper activities correlated with the total copper concentration in the pore water and the pH. The organic matter in the solid phase had no influence on the pCu in these soil sets. Earthworms were exposed to the soils for 28 days, after which survival was scored. Observed earthworm mortality after 28-days exposure was plotted as a function of the log-transformed difference between predicted (log10 transformed) LC50-values and measured values of pCu for validation of the regression model. The results obtained were in agreement with the assumption that mortality is to be observed in those soils where the predicted LC50 exceeds the measured pCu. However, a structural underestimation of toxicity was apparent, which is most likely due to mixture effects related to the presence of additional substances in field soils. Nevertheless, the trend of the results in the validation tests demonstrates that the newly developed toxicity model is a useful tool in predicting lethality of copper contamination to earthworms in field soils.
    • Development and application of a sediment toxicity test using the benthic cladoceran Chydorus sphaericus.

      Dekker, T; Greve, Gerdit D; Laak, T L ter; Boivin, Marie-Elène Y; Veuger, B; Gortzak, G; Dumfries, S; Lücker, S M G; Kraak, Michiel H S; Admiraal, Wim; Geest, H G van der (2006-03-01)
      This study reports on the development and application of a whole sediment toxicity test using a benthic cladoceran Chydorus sphaericus, as an alternative for the use of pelagic daphnids. A C. sphaericus laboratory culture was started and its performance under control conditions was optimised. The test was firstly validated by determining dose-response relationships for aqueous cadmium and copper and ammonia, showing a sensitivity of C. sphaericus (96 h LC(50) values of 594 microg Cd/L, 191 microg Cu/L and 46 mg ammonia/L at pH 8) similar to that of daphnids. Next, sediment was introduced into the test system and a series of contaminated sediments from polluted locations were tested. A significant negative correlation between survival and toxicant concentrations was observed. It is concluded that the test developed in the present study using the benthic cladoceran C. sphaericus is suitable for routine laboratory sediment toxicity testing.
    • Do inhaled carbon nanoparticles translocate directly into the circulation in humans?

      Mills, Nicholas L; Amin, Nadia; Robinson, Simon D; Anand, Atul; Davies, John; Patel, Dilip; Fuente, Jesus M de la; Cassee, Flemming R; Boon, Nicholas A; Macnee, William; Millar, Alistair M; Donaldson, Ken; Newby, David E (2006-02-15)
      RATIONALE: Increased exposure to particulate air pollution (PM(10)) is a risk factor for death and hospitalization with cardiovascular disease. It has been suggested that the nanoparticulate component of PM(10) is capable of translocating into the circulation with the potential for direct effects on the vasculature. OBJECTIVE: The study's aim was to determine the extent to which inhaled technetium-99m ((99m)Tc)-labeled carbon nanoparticles (Technegas) were able to access the systemic circulation. METHODS AND MAIN RESULTS: Ten healthy volunteers inhaled Technegas and blood samples were taken sequentially over the following 6 h. Technegas particles were 4-20 nm in diameter and aggregated to a median particle diameter of approximately 100 nm. Radioactivity was immediately detected in blood, with levels increasing over 60 min. Thin-layer chromatography of whole blood identified a species that moved with the solvent front, corresponding to unbound (99m)Tc-pertechnetate, which was excreted in urine. There was no evidence of particle-bound (99m)Tc at the origin. gamma Camera images demonstrated high levels of Technegas retention (95.6 +/- 1.7% at 6 h) in the lungs, with no accumulation of radioactivity detected over the liver or spleen. CONCLUSIONS: The majority of (99m)Tc-labeled carbon nanoparticles remain within the lung up to 6 h after inhalation. In contrast to previous published studies, thin-layer chromatography did not support the hypothesis that inhaled Technegas carbon nanoparticles pass directly from the lungs into the systemic circulation.
    • Driving forces from soil invertebrates to ecosystem functioning: the allometric perspective.

      Mulder, Christian (2006-10-01)
      The European soil policy is being focussed towards a more conscious and sustainable use of the soil, taking into account ecological, economical and societal dimensions. Living soil organisms are reliable bioindicators, as they provide the best reflection of the soil system, ecological services and ecosystem functioning therein. These most complex (bio)physical systems indicate, among others, the energy flow. Such processes can be described by rather simple power law relationships. In fact, the average body mass (dry weight) can be seen as an inherent species property, while population density is a much more flexible parameter reflecting ecosystem state. In this study, I review the interactions between these items in relation to feedbacks and conjectured relationships which can be seen as ecological networks. From this novel perspective, allometry can be used as an integrated measure for the anthropogenic influence on landscapes and related food webs. Allometry is, therefore, a perfect surrogate for land use intensity in modelling of field effects for restoration ecology and conservation biology. Robust correlations will be addressed between the density dependence of invertebrates and the ability of soil systems themselves to recover after disturbance. Quantitative indicators of soil community composition and related ecological services are proposed and their application for ecological risk assessment is illustrated.
    • Effects of the antithyroid agent propylthiouracil in a partial life cycle assay with zebrafish.

      Ven, Leo T M van der; Brandhof, Evert-Jan van den; Vos, José H; Power, Deborah M; Wester, Piet W (2006-01-01)
      Some ubiquitous pollutants of the aquatic environment, such as PCBs or other polyhalogenated aromatic hydrocarbons, may disrupt the thyroid hormone system. In a partial life cycle assay with zebrafish (Danio rerio), we studied the effects of the reference compound propylthiouracil (PTU) on reproduction, growth and development, histopathology of some target tissues, and plasma thyroid hormone levels. PTU induced a concentration-dependent increase of egg production with a concomitant decrease of mature oocyte size but had no effect on fertilization rate or hatching. In F1, serious dysmorphogenesis was found in 4 dph larvae at the highest PTU level tested (100 mg/L), and there was a dose-dependent decrease in body length and weight at 42 dph (significant at 100 mg/L PTU). At this time, there was also a decreased scale thickness, suggesting inhibited metamorphosis, detectable at 1 mg/L PTU and higher. PTU also induced activation of the thyroid follicles in a concentration-dependent way, in juveniles associated with hyperemia in the thyroid area, and depletion of liver glycogen. Effects in adults were associated with decreased circulating levels of the thyroid hormones T3 and T4. These observations indicate that disruption of the thyroid hormone system may affect the fitness of these aquatic organisms. The zebrafish model may contribute to the identification of thyroid hormone disrupting activity in water samples and also in the interpretation of histological observations in free-ranging fish species.
    • Estimating the Impact of High-Production-Volume Chemicals on Remote Ecosystems by Toxic Pressure Calculation

      Harbers, Jasper V; Huijbregts, Mark A J; Posthuma, Leo; Meent, Dik van de (2006-01-14)
      Although many chemicals are in use, the environmental impacts of only a few have been established, usually on per-chemical basis. Uncertainty remains about the overall impact of chemicals. This paper estimates combined toxic pressure on coastal North Sea ecosystems from 343 high-production-volume chemicals used within the catchment of rivers Rhine, Meuse, and Scheldt. Multimedia fate modeling and species sensitivity distribution-based effects estimation are applied. Calculations start from production volumes and emission rates and use physicochemical substance properties and aquatic ecotoxicity data. Parameter uncertainty is addressed by Monte Carlo simulations. Results suggest that the procedure is technically feasible. Combined toxic pressure of all 343 chemicals in coastal North Seawater is 0.025 (2.5% of the species are exposed to concentration levels above EC50 values), with a wide confidence interval of nearly 0-1. This uncertainty appears to be largely due to uncertainties in interspecies variances of aquatic toxicities and, to a lesser extent, to uncertainties in emissions and degradation rates. Due to these uncertainties, the results support gross ranking of chemicals in categories: negligible and possibly relevant contributions only. With 95% confidence, 283 of the 343 chemicals (83%) contribute negligibly (less than 0.1%) to overall toxic pressure, and only 60 (17%) need further consideration.
    • Evolution of aerosol optical thickness over Europe during the August 2003 heat wave as seen from CHIMERE model simulations and POLDER data

      Hodzic, A; Vautard, R; Chepfer, H; Goloub, P; Menut, L; Chazette, P; Deuzé, J L; Apituley, A; Couvert, P (2006-05-30)
      This study describes the atmospheric aerosol load encountered during the large-scale pollution episode that occurred in August 2003, by means of the aerosol optical thicknesses (AOTs) measured at 865 nm by the Polarization and Directionality of the Earth's Reflectances (POLDER) sensor and the simulation by the CHIMERE chemistry-transport model. During this period many processes (stagnation, photochemistry, forest fires) led to unusually high particle concentrations and optical thicknesses. The observed/simulated AOT comparison helps understanding the ability of the model to reproduce most of the gross AOT features observed in satellite data, with a general agreement within a factor 2 and correlations in the 0.4–0.6 range. However some important aerosol features are missed when using regular anthropogenic sources. Additional simulations including emissions and high-altitude transport of smoke from wildfires that occurred in Portugal indicate that these processes could dominate the AOT signal in some areas. Our results also highlight the difficulties of comparing simulated and POLDER-derived AOTs due to large uncertainties in both cases. Observed AOT values are significantly lower than the simulated ones (30–50%). Their comparison with the ground-based Sun photometer Aerosol Robotic Network (AERONET) measurements suggests, for the European sites considered here, an underestimation of POLDER-derived aerosol levels with a factor between 1 and 2. AERONET AOTs compare better with simulations (no particular bias) than POLDER AOTs.
    • Exposure-effect relations between aircraft and road traffic noise exposure at school and reading comprehension: the RANCH project.

      Clark, Charlotte; Martin, Rocio; Kempen, Elise van; Alfred, Tamuno; Head, Jenny; Davies, Hugh W; Haines, Mary M; Lopez Barrio, Isabel; Matheson, Mark; Stansfeld, Stephen A (2006-01-01)
      Transport noise is an increasingly prominent feature of the urban environment, making noise pollution an important environmental public health issue. This paper reports on the 2001-2003 RANCH project, the first cross-national epidemiologic study known to examine exposure-effect relations between aircraft and road traffic noise exposure and reading comprehension. Participants were 2,010 children aged 9-10 years from 89 schools around Amsterdam Schiphol, Madrid Barajas, and London Heathrow airports. Data from The Netherlands, Spain, and the United Kingdom were pooled and analyzed using multilevel modeling. Aircraft noise exposure at school was linearly associated with impaired reading comprehension; the association was maintained after adjustment for socioeconomic variables (beta = -0.008, p = 0.012), aircraft noise annoyance, and other cognitive abilities (episodic memory, working memory, and sustained attention). Aircraft noise exposure at home was highly correlated with aircraft noise exposure at school and demonstrated a similar linear association with impaired reading comprehension. Road traffic noise exposure at school was not associated with reading comprehension in either the absence or the presence of aircraft noise (beta = 0.003, p = 0.509; beta = 0.002, p = 0.540, respectively). Findings were consistent across the three countries, which varied with respect to a range of socioeconomic and environmental variables, thus offering robust evidence of a direct exposure-effect relation between aircraft noise and reading comprehension.
    • Functional recovery of biofilm bacterial communities after copper exposure.

      Boivin, Marie-Elène Y; Massieux, Boris; Breure, Anton M; Greve, Gerdit D; Rutgers, Michiel; Admiraal, Wim (2006-03-01)
      Potential of bacterial communities in biofilms to recover after copper exposure was investigated. Biofilms grown outdoor in shallow water on glass dishes were exposed in the laboratory to 0.6, 2.1, 6.8 micromol/l copper amended surface water and a reference and subsequently to un-amended surface water. Transitions of bacterial communities were characterised with denaturing gradient gel electrophoresis (DGGE) and community-level physiological profiles (CLPP). Exposure to 6.8 micromol/l copper provoked distinct changes in DGGE profiles of bacterial consortia, which did not reverse upon copper depuration. Exposure to 2.1 and 6.8 micromol/l copper was found to induce marked changes in CLPP of bacterial communities that proved to be reversible during copper depuration. Furthermore, copper exposure induced the development of copper-tolerance, which was partially lost during depuration. It is concluded that bacterial communities exposed to copper contaminated water for a period of 26 days are capable to restore their metabolic attributes after introduction of unpolluted water in aquaria for 28 days.
    • Immunotoxic effects of chemicals: A matrix for occupational and environmental epidemiological studies.

      Veraldi, Angela; Costantini, Adele Seniori; Bolejack, Vanessa; Miligi, Lucia; Vineis, Paolo; Loveren, Henk van (2006-12-01)
      BACKGROUND: Many biological and chemical agents have the capacity to alter the way the immune system functions in human and animals. This study evaluates the immunotoxicity of 20 substances used widely in work environments. METHODS: A systematic literature search on the immunotoxicity of 20 chemicals was performed. The first step was to review literature on immunotoxicity testing and testing schemes adopted for establishing immunotoxicity in humans. The second step consisted of providing a documentation on immunotoxicity of substances that are widely used in work environment, by building tables for each chemical of interest (benzene, trichloroethylene, PAHs, crystalline silica, diesel exhausts, welding fumes, asbestos, styrene, formaldehyde, toluene, vinyl chloride monomer, tetrachloroethylene, chlorophenols, 1,3-butadiene, mineral oils, P-dichlorobenzene, dichloromethane, xylene, 1,1,1-trichloroethane, ethylene oxide). The third step was the classification of substances; an index (strong, intermediate, weak, nil) was assigned on the basis of the evidence of toxicity and type of immunotoxic effects (immunosuppression, autoimmunity, hypersensitivity) on the basis of the immune responses. Finally substances were assigned a score of immunotoxic power. RESULTS: Tables have been produced that include information for the 20 substances of interest, based on 227 animal studies and 94 human studies. Each substance was assigned an index of immunotoxic evidence, a score of immunotoxic power and type of immunotoxic effect. CONCLUSIONS: This matrix can represent a tool to identify chemicals with similar properties concerning the toxicity for the immune system, and to interpret epidemiological studies on immune-related diseases.
    • Is cumulative fossil energy demand a useful indicator for the environmental performance of products?

      Huijbregts, Mark A J; Rombouts, Linda J A; Hellweg, Stefanie; Frischknecht, Rolf; Hendriks, A Jan; Meent, Dik van de; Ragas, Ad M J; Reijnders, Lucas; Struijs, Jaap (2006-02-01)
      The appropriateness of the fossil Cumulative Energy Demand (CED) as an indicator for the environmental performance of products and processes is explored with a regression analysis between the environmental life-cycle impacts and fossil CEDs of 1218 products, divided into the product categories "energy production", "material production", "transport", and "waste treatment". Our results show that, for all product groups but waste treatment, the fossil CED correlates well with most impact categories, such as global warming, resource depletion, acidification, eutrophication, tropospheric ozone formation, ozone depletion, and human toxicity (explained variance between 46% and 100%). We conclude that the use of fossil fuels is an important driver of several environmental impacts and thereby indicative for many environmental problems. It maytherefore serve as a screening indicatorfor environmental performance. However, the usefulness of fossil CED as a stand-alone indicator for environmental impact is limited by the large uncertainty in the product-specific fossil CED-based impact scores (larger than a factor of 10 for the majority of the impact categories; 95% confidence interval). A major reason for this high uncertainty is nonfossil energy related emissions and land use, such as landfill leachates, radionuclide emissions, and land use in agriculture and forestry.
    • Long-term evolution of upper stratospheric ozone at selected stations of the Network for the Detection of Stratospheric Change (NDSC)

      Steinbrecht, W; Claude, H; Schönenborn, F; McDermid, I S; Leblanc, T; Godin, S; Song, T; Swart, D P J; Meijer, Y J; Bodeker, G E; Connor, B J; Kämpfer, N; Hocke, K; Calisesi, Y; Schneider, N; Noë, J de la; Parrish, A D; Boyd, I S; Brühl, C; Steil, B; Giorgetta, M A; Manzini, E; Thomason, L W; Zawodny, J M; McCormick, M P; Russell, J M; Bhartia, P K; Stolarski, R S; Hollandsworth-Frith, S M (American Geophysical Union., 2006-05-31)
      The long-term evolution of upper stratospheric ozone has been recorded by lidars and microwave radiometers within the ground-based Network for the Detection of Stratospheric Change (NDSC), and by the space-borne Solar Backscatter Ultra-Violet instruments (SBUV), Stratospheric Aerosol and Gas Experiment (SAGE), and Halogen Occultation Experiment (HALOE). Climatological mean differences between these instruments are typically smaller than 5% between 25 and 50 km. Ozone anomaly time series from all instruments, averaged from 35 to 45 km altitude, track each other very well and typically agree within 3 to 5%. SBUV seems to have a slight positive drift against the other instruments. The corresponding 1979 to 1999 period from a transient simulation by the fully coupled MAECHAM4-CHEM chemistry climate model reproduces many features of the observed anomalies. However, in the upper stratosphere the model shows too low ozone values and too negative ozone trends, probably due to an underestimation of methane and a consequent overestimation of ClO. The combination of all observational data sets provides a very consistent picture, with a long-term stability of 2% or better. Upper stratospheric ozone shows three main features: (1) a decline by 10 to 15% since 1980, due to chemical destruction by chlorine; (2) two to three year fluctuations by 5 to 10%, due to the Quasi-Biennial Oscillation (QBO); (3) an 11-year oscillation by about 5%, due to the 11-year solar cycle. The 1979 to 1997 ozone trends are larger at the southern mid-latitude station Lauder (45°S), reaching −8%/decade, compared to only about −6%/decade at Table Mountain (35°N), Haute Provence/Bordeaux (≈45°N), and Hohenpeissenberg/Bern(≈47°N). At Lauder, Hawaii (20°N), Table Mountain, and Haute Provence, ozone residuals after subtraction of QBO- and solar cycle effects have levelled off in recent years, or are even increasing. Assuming a turning point in January 1997, the change of trend is largest at southern mid-latitude Lauder, +11%/decade, compared to +7%/decade at northern mid-latitudes. This points to a beginning recovery of upper stratospheric ozone. However, chlorine levels are still very high and ozone will remain vulnerable. At this point the most northerly mid-latitude station, Hohenpeissenberg/Bern differs from the other stations, and shows much less clear evidence for a beginning recovery, with a change of trend in 1997 by only +3%/decade. In fact, record low upper stratospheric ozone values were observed at Hohenpeissenberg/Bern, and to a lesser degree at Table Mountain and Haute Provence, in the winters 2003/2004 and 2004/2005.
    • Long-term personal exposure to traffic-related air pollution among school children, a validation study.

      Roosbroeck, Sofie van; Wichmann, Janine; Janssen, Nicole A H; Hoek, Gerard; Wijnen, Joop H van; Lebret, Erik; Brunekreef, Bert (2006-09-15)
      Several recent studies suggest an association between long-term exposure to traffic-related air pollution and health. Most studies use indicators of exposure such as outdoor air pollution or traffic density on the street of residence. Little information is available about the validity of these measurements as an estimate of long-term personal exposure to traffic-related air pollution. In this pilot study, we assessed outdoor and personal exposure to traffic-related air pollution in children living in homes on streets with different degree of traffic intensity. The personal exposure of 14 children aged 9-12 years to 'soot', NO(x) (NO and NO(2)) was assessed in Amsterdam between March and June 2003. Each child's personal exposure was monitored during four repeated 48-h periods. Concurrently, in- and outdoor NO(x) measurements were carried out at the school and at the home of each participating child. Measurements were supplemented by a questionnaire on time activity patterns and possible indoor sources. Flow-controlled battery operated pumps in a made-to-fit backpack were used to sample personal exposure to 'soot', determined from the reflectance of PM(2.5) filters. Exposure to NO(x) was assessed using Ogawa passive samplers. Children living near busy roads were found to have a 35% higher personal exposure to 'soot' than children living at an urban background location, despite that all children attended the same school that was located away from busy roads. Smaller contrasts in personal exposure were found for NO (14%), NO(2) (15%) and NO(x) (14%). This finding supports the use of 'living near a busy road' as a measure of exposure in epidemiological studies on the effects of traffic-related air pollution in children.
    • Longitudinal analysis of tick densities and Borrelia, Anaplasma, and Ehrlichia infections of Ixodes ricinus ticks in different habitat areas in The Netherlands.

      Wielinga, Peter R; Gaasenbeek, Cor; Fonville, Manoj; Boer, Albert de; Vries, Ankje de; Dimmers, Wim; Akkerhuis Op Jagers, Gerard; Schouls, Leo M; Borgsteede, Fred; Giessen, Joke W B van der (2006-12-01)
      From 2000 to 2004, ticks were collected by dragging a blanket in four habitat areas in The Netherlands: dunes, heather, forest, and a city park. Tick densities were calculated, and infection with Borrelia burgdorferi and Anaplasma and Ehrlichia species was investigated by reverse line blot analysis. The lowest tick density was observed in the heather area (1 to 8/100 m2). In the oak forest and city park, the tick densities ranged from 26 to 45/100 m2. The highest tick density was found in the dune area (139 to 551/100 m2). The infection rates varied significantly for the four study areas and years, ranging from 0.8 to 11. 5% for Borrelia spp. and 1 to 16% for Ehrlichia or Anaplasma (Ehrlichia/Anaplasma) spp. Borrelia infection rates were highest in the dunes, followed by the forest, the city park, and heather area. In contrast, Ehrlichia/Anaplasma was found most often in the forest and less often in the city park. The following Borrelia species were found: Borrelia sensu lato strains not identified to the species level (2.5%), B. afzelii (2.5%), B. valaisiana (0.9%), B. burgdorferi sensu stricto (0.13%), and B. garinii (0.13%). For Ehrlichia/Anaplasma species, Ehrlichia and Anaplasma spp. not identified to the species level (2.5%), Anaplasma schotti variant (3.5%), Anaplasma phagocytophilum variant (0.3%), and Ehrlichia canis (0.19%) were found. E. canis is reported for the first time in ticks in The Netherlands in this study. Borrelia lusitaniae, Ehrlichia chaffeensis, and the human granylocytic anaplasmosis agent were not detected. About 1.6% of the ticks were infected with both Borrelia and Ehrlichia/Anaplasma, which was higher than the frequency predicted from the individual infection rates, suggesting hosts with multiple infections or a possible selective advantage of coinfection.