Abstract: An active biomonitoring of the heavy
metals pollution experiment was undertaken by
means of the bryophyte species Scleropodium
purum transplanted at three different sites exposed
to rural, traffic, or industrial influences.
Concentrations of about 40 elements in S. purum were determined by instrumental neutron activation
analysis and inductively coupled plasma
mass spectrometry. Accumulation rates of heavy
metals were determined in the three sites. These
accumulation rates in polluted sites were matched
together and also to those recorded at the rural
site. The changes of the accumulation rate of
heavy metals in S. purum versus their concentrations
in PM10 particles simultaneously collected
above show some different accumulation properties
of S. purum according to elements and sites.
S. purum has a weak efficiency in the three sites
to accumulate elements like V, Cr, Cu, Zn, As,
Se, Sb, and Pb originating from atmospheric hot
sources generally enriched in particulates matter
(PM10), whereas it is particularly high for Br, Th,
and Rb. For other elements, Co, La, Ce, and
Hf, and rare earth elements, Fe, Sr, Nb, Ti, Al,
and Sc, the collection efficiency by S. purum is
intermediate. In the industrial site Dunkerque,
a magnification of the collection efficiency by
S. purum for elements originating from steel and
aluminum productions and petroleum refinement
suggests that these metals could be enriched in
coarse particles with a better accumulation by the
bryophyte with respect to PM10
Abstract: The diet of the Barn Owl (Tyto alba (Scopoli, 1769)) was studied over an 8-year period in the Jura mountains of France, during two population surges of its main rodent prey (common voles (Microtus arvalis (Pallas, 1778)) and European water voles (Arvicola terrestris (L.,1758))), allowing us to test whether T. alba is an opportunistic predator as is often cited in the literature or exhibits more complex patterns of prey selection as is reported in arid environments. Small mammals were sampled by trapping and index methods. We observed (i) significant correlations between the proportions of A. terrestris and M. arvalis and woodland rodents in the diet and their respective densities in the field; (ii) interactions between populations of A. terrestris and M. arvalis, indicating that the proportion of each species in diet was affected by the density of the other; (iii) proportions of red-toothed shrews (genus Sorex (L., 1758)) in the diet did not correlate with their abundance in the field, indicating that those species were likely to be preyed upon when others were no longer available. This confirms that T. alba is generally opportunistic; however, prey selection of a focal species (e.g., Sorex spp., grassland species) can be affected by the density or availability of the other prey species
Abstract: We investigate the relationship between landscape heterogeneity and the spatial distribution of small mammals in two areas of Western Sichuan, China. Given a large diversity of species trapped within a large number of habitats, we first classified small mammal assemblages and then modelled the habitat of each in the space of quantitative environmental descriptors. Our original two step "classify then model" procedure is appropriate for the frequently encountered study scenario: trapping data collected in remote areas with sampling guided by expert field knowledge. In the classification step, we defined assemblages by grouping sites of similar species composition and relative densities using an expert-class-merging procedure which reduced redundancy in the habitat factor used within a multinomial logistic regression predicting species trapping probabilities. Assemblages were thus defined as mixtures of small mammal frequency distributions in discrete groups of sampled sites. In the modelling step, assemblages' habitats and environments of the two sampled areas were discriminated in the space of remotely sensed environmental descriptors. First, we compared the discrimination of assemblage/study areas by linear and non-linear forms of discriminant analysis (linear discriminant analysis versus mixture discriminant analysis) and of multiple regression (generalized linear models versus multiple adaptive regression splines). The "best" predictive modelling technique was then used to quantify the contribution of each environmental variable in discriminations of assemblages and areas. Mixtures of Gaussians provided a more efficient model of assemblage coverage in environmental space than a single Gaussian cluster model. However, non-linearity in assemblage response to environmental gradients was consistently predicted with lower deviance and misclassification error by multiple adaptive regression splines. The two study areas were mainly discriminated along vegetation indices. However, although the normalized difference vegetation index (NDVI) could discriminate forested from non-forested habitats, its power to discriminate assemblages in Maerkang, where a greater diversity of forest habitat was observed, was seen to be limited, and in this case NDVI was outperformed by the enhanced vegetation index (EVI). Our analyses highlight previously unobserved differences between the environments and small mammal communities of two fringe areas of the Tibetan plateau and suggests that a biogeographical approach is required to elucidate ecological processes in small mammal communities and to reduce extrapolation uncertainty in distribution mapping. (C) 2009 Elsevier B.V. All rights reserved.
Abstract: PM10 particles were collected over three sites in France. The first one, Montagney was a rural site that was considered as a reference site. The second site Saclay, close to a highway, was used to study the influence of the traffic. The third site was Dunkerque, one of the most industrial areas in France for the production of steel, aluminium and petroleum refinement. More than 50 element concentrations were determined by instrumental neutron activation analysis and inductively coupled plasma-mass spectrometry. Comparisons between Saclay and Montagney shown that some elements, considered as crustal elements had similar concentration variations and weak (close to 1) enrichment factors. Elements with enrichment factors higher than 10 shown in Montagney correlated variations, with a Winter maximum, that should be due to Winter heating sources. Over Saclay, most of elements with high enrichment factors were attributed to the dense traffic of the highway. This is particularly true for Mn, Fe, Zn, Ba, Sb, Cu. Some additional elements correlated also, without a particular origin that can be ascertained. In Dunkerque, the most important industry is steel production. Correlation studies shown that Tl, Cs, Ba, Ag, Cu, Rb, Se, Mn, Pb concentration variations were closely associated to the Fe concentration variations. The second polluting industry is aluminium production. Correlation studies allowed to associate Ni, Y, Co, V, rare earth elements, Ti, Sr, Th, U, Ca, Sc, concentration variations to the aluminium concentration variations. A third important industry is petroleum refinement. The only element observed here and that is suspected to be emitted more specifically is La, used in cracking processes. An important enrichment of La with respect to Ce is observed. A strong decrease of the ratio Cl/Na was observed over the three sites, between the beginning of the experiment in Autumn 2005, and its end in Spring 2006. This was attributed to a release of gaseous HCl, produced by acidification of aerosols by other pollutants like NO (x) and SOx , that should have been oxidized to NO2 and SO3, then dissolved in the aerosols. The effects responsible for the loss of Cl, represents a large surface and long-term pollution event over the North of France. This work allowed a characterization of the heavy metal concentrations of the aerosol that will sustain results published in a companion paper, and that concerned the bio-accumulation of metals by Scleropodium purum, simultaneously exposed in the same sites.
Abstract: This paper addresses the issue of whether landscape structure affects A. terrestris population kinetics on a neighbourhood spatial scale, and if so, at what spatial scale is that effect at its maximum. We investigated how the growth of A. terrestris populations is influenced by the landscape context of parcels used for hay production in the French Jura Mountains. Five landscape metrics (relative area of grassland, mean patch area of grassland, patch density of grassland, woodland patch density in grassland, grassland-woodland edge density) were computed over an increasing radius around each parcel (max. 3 km). Redundancy analysis showed that the extent, rate and early onset of A. terrestris population growth were favoured in open grassland areas. Landscape effects on A. terrestris populations as determined by the five metrics are scale-dependent: mean patch area of grassland, patch density of grassland and woodland patch density in grassland had an impact on a grassland parcel within a neighbourhood radius of about 800 m, while relative area of grassland and grassland-woodland edge density had an impact within a neighbourhood radius of about 400 m. Those findings corroborate earlier hypotheses about a multifactorial regulation of A. terrestris populations and a spatial hierarchy of regulating factors. They have potential implications in terms of landscape management and small mammal pest control.
Abstract: Deforestation is a major environmental issue driving the loss of animal and plant species. Afforestation has recently been promoted to conserve and restore Chinese forest ecosystems. We investigated the distribution of small-mammal assemblages in an area where forest and associated deforestation habitats dominate, and in an agricultural area where afforestation is ongoing in the Loess Plateau of southern Ningxia Autonomous Region, P. R. China. Multiple trapping was used. Assemblages were defined based on the multinomial probability distribution and information theory. Species turnover between assemblages of deforested and afforested habitats was high, although no clear effect on species richness was observed. The two assemblages described along the deforestation gradient displayed higher diversity, whereas diversity was lower in assemblages identified in afforested habitats where Cricetulus longicaudatus, a known agricultural pest in various areas of China, clearly dominated. The threatened Sorex cylindricauda and Eozapus setchuanus were recorded along the deforestation gradient but not in plantations. Therefore, habitats present along a deforestation succession in this part of Ningxia sustain a high diversity of small mammals and include species of conservation concern. At the present stage of its process ( maximum 15 years), afforestation in southern Ningxia favours the dominance of an agricultural pest.
Abstract: We studied the effects of lead pollution on testate amoebae communities living on Sphagnum fallax by growing this moss under controlled conditions. A progressive series of lead (Pb) concentration was used in the growing solution of the mosses: 0 (control), 625 and 2500 mu g L-1. The mosses were sampled and analysed for accumulated Pb and testate amoeba communities after 0, 6, 12, and 20 weeks. Species richness, total density and total biomass of testate amoebae declined in response to the Pb treatment and changed over time. The Pb x Time cross-effect was significant for species richness, and total density but not for the total biomass and Shannon diversity. Furthermore, the testate amoebae species richness and the total density were negatively correlated to the Pb concentrations actually accumulated in the moss at the end of the experiment. Species-specific responses of testate amoebae to Pb pollution were identified. Our results thus confirm the sensitivity of testate amoebae to lead pollution. (c) 2007 Elsevier Inc. All rights reserved.
Abstract: Ecotoxicological studies usually focus on single microbial species under controlled conditions. As a result, little is known about the responses of different microbial functional groups or individual species to stresses. In an aim to assess the response of complex microbial communities to pollution in their natural habitat, we studied the effect of a simulated lead pollution on the microbial community (bacteria, cyanobacteria, protists, fungi, and micrometazoa) living on Sphagnum fallax. Mosses were grown in the laboratory with 0 (control), 625, and 2,500 mu g L-1 of Pb2+ diluted in a standard nutrient solution and were sampled after 0, 6, 12, and 20 weeks. The biomasses of bacteria, microalgae, testate amoebae, and ciliates were dramatically and significantly decreased in both Pb addition treatments after 6, 12, and 20 weeks in comparison with the control. The biomass of cyanobacteria declined after 6 and 12 weeks in the highest Pb treatment. The biomasses of fungi, rotifers, and nematodes decreased along the duration of the experiment but were not significantly affected by lead addition. Consequently, the total microbial biomass was lower for both Pb addition treatments after 12 and 20 weeks than in the controls. The community structure was strongly modified due to changes in the densities of testate amoebae and ciliates, whereas the relative contribution of bacteria to the microbial biomass was stable. Differences in responses among the microbial groups suggest changes in the trophic links among them. The correlation between the biomass of bacteria and that of ciliates or testate amoebae increased with increasing Pb loading. We interpret this result as an effect on the grazing pathways of these predators and by the Pb effect on other potential prey (i.e., smaller protists). The community approach used here complements classical ecotoxicological studies by providing clues to the complex effect of pollutant-affecting organisms both directly and indirectly through trophic effects and could potentially find applications for pollution monitoring.
Abstract: We studied the relationships between testate amoeba communities and heavy metal (Pb, Cd, Zn, Ni, Cu, Mn, and Fe) concentrations in the moss Barbula indica sampled at 29 sites in and around the city of Hanoi (Vietnam). Our first approach was to compare the heavy metal concentrations and testate amoeba variables between the city (zone 1) and the surrounding (zone 2). Mean moss concentrations of Pb, Cd, Zn, Ni, and Cu were significantly higher and testate amoeba species richness and abundance were significantly lower in zone 1 and the abundance of eight taxa differed significantly between the two zones. We then studied the correlation between heavy metals and testate amoebae. Species richness and abundance were correlated negatively to Pb concentration. Shannon H' was negatively correlated to both Pb and Cd. The abundance of several species was negatively correlated with Pb, Cd, Zn, and Ni; however, at the community level, Pb emerged as the only significant variable in a redundancy analysis. Our results suggest that testate amoebae are sensitive to and may be good bioindicators for heavy metal pollution, especially lead. Further research is needed to understand the causal relationships underlying the observed patterns.
Abstract: The impact of farming practices (fertilization, mowing, grazing, ploughing, etc.) on Arvicola terrestris scherman population dynamics was investigated using index methods during the increase and the high density phase of a population cycle taking into account Talpa europaea population abundance. Farming practices significantly impacted A. terrestris populations. More intensive production indicators such as organic fertilisation and mowing correlated with the early growth of vole population. In contrast, disturbances such as grazing and soil cultivation correlated with lower vole population abundance during the high density phase. Furthermore, this study indicates that A. terrestris population dynamics patterns was governed by multifactorial processes. The way those results may help to rethink population outbreak control through farming practices complementary to other methods is discussed. (C) 2007 Elsevier B.V. All rights reserved.
Abstract: This paper documents the exposure pattern of a population of small mammals to bromadiolone over time in a field-scale follow up. This is the first assessment of the field-scale effect of such control operation on the availability of bromadiolone-exposed A. terrestris prey to nontarget predator species. It indicates that an important risk of poisoning of nontarget species does exist during large-scale field control operations with bromadiolone, which is contradictory to results obtained from laboratory experiments in the early 1980s and consistent with the secondary poisoning hazards due to repeated exposure regularly reported during the past 20 years. (c) 2006 Elsevier Inc. All rights reserved.
Abstract: Small mammal distribution was studied along a grazing gradient in a pastoral landscape of the Tibetan plateaus of Western Sichuan, China. Smaller small mammals (< 100 g) were sampled using standard trapping. The link between habitat and both smaller and larger small-mammal distribution on a landscape scale was estimated using landscape transects. The relative density of the Microtus oeconomus/limnophilus complex ranged from higher levels in fenced grassland and bushes (i.e., low grazing pressure), to lower levels in habitats with a high grazing pressure, where this species was not trapped. Ochotona curzoniae, O. cansus and Cricetulus kamensis displayed a reverse gradient, with higher relative densities in overgrazed habitats (bare ground). The distribution of Microtus irene was restricted to two slope habitats: rocky slopes and Stellera chamaejasme grassland. Microtus leucurus was only trapped in Potentilla fruticosa bushes and in a single grassland type with an intermediate stage of degradation. These results suggest a differential response of the small mammal species in terms of relative density to grazing pressure level.
Abstract: Despite the dramatic decrease of atmospheric lead (Pb) concentrations in urban areas of most industrialised countries, we hypothesised that urban common blackbirds (Turdus merula) may still be contaminated by Pb concentrations of toxicological concern due to transfer from soil through the food chain. We sampled blackbirds and earthworms, one of their main preys, in Besanqon, a middle-size city of Eastern France (where atmospheric Pb concentrations decreased from 0.5 mu g/m(3) in 1987 to nearly 0 in 2002) and in a rural reference site. Lead concentrations were determined in the tissues of the different functional groups of earthworms (anecic, epigeous and endogeous) and in blood, washed and unwashed outermost tail feathers and breast feathers of blackbirds. Fresh masses and an index of individual body condition were measured in the two blackbird populations as biomarkers of possible toxic effects. Lead concentrations in earthworms did not differ among functional groups but were significantly higher in urban individuals than in rural ones. Concentrations in outermost tail feathers, breast feathers and blood were significantly higher in urban blackbirds (7.75 +/- 4.50, 3.15 +/- 1.77 and 0.15 +/- 0.09 mu g/g, respectively) than in rural individuals. In urban blackbirds, concentrations in washed and unwashed outermost tail feathers allowed estimating the external contamination (probably due to deposition of dusts and/or to excretion of the uropygial gland) at 37% of the total Pb concentration of the unwashed feathers. Remaining 63% should be linked to food chain transfer of persistent Pb from urban soils. Among the 23 sampled blackbirds, 4 of them (3 in the urban site and I in the rural site) exhibited blood Pb concentrations higher than the benchmark value (0.20 mu g/g) related to subclinical and physiological effects in birds. Variations in body condition index were not correlated to Pb concentrations in blackbird tissues. Present results suggest that Pb may still be of environmental concern for blackbirds in urban areas because of the persistence of Pb in soils and its transfer through the food chain. (c) 2006 Elsevier B.V. All rights reserved.
Abstract: To assess the potential use of testate amoebae as biomonitors of atmospheric pollution we studied the relationship between atmospheric nitrogen dioxide (NO2) pollution and testate amoebae density, diversity, and community structure (Protista: Rhizopoda) in (zone 1) and around (zone 2) the city of Besangon, France. NO2 concentrations were on average significantly lower in the city zone (mean: 34.8 +/- 9.5 mug/m(3)) than in the periphery zone (mean: 14.6 +/- 4.7 mug/m(3)). The density of living amoebae was correlated with that of empty tests (0.001 < p < 0.043 depending on the species), therefore we used the total of dead and living amoebae in all analyses. Testate amoebae species richness was significantly lower in the city (4.7 species) than in the less polluted surrounding areas (6.0 species) but the total density did not vary between the two zones. Of the nine recorded taxa, the density of only one, Paraquadrula irregularis differed significantly between the two zones (p = 0.017), being present in all periphery samples and absent from all city samples. These results are interesting because the pollution level recorded was very low. Although further work is needed before testate amoebae can be used as a monitoring tool for atmospheric pollution, these results suggest they may have a potential for such a use. Further work should focus on potential effects of other pollutants and studies under controlled conditions.
Abstract: Background: Individual exposure to NO2 and O-3 has been estimated in an urban population sample in southern France and the determinants identified. The present study was conducted to evaluated individual exposure to NO2 and O-3 and to identify the environmental determinants of exposure in a larger population living in different environmental conditions. Methods: Two hundred ninety-four volunteers were recruited from the SUVIMAX sample in Ile-deFrance. The study covered 2 periods of 5 consecutive days, one in winter and rite other in the fall of 1998. Passive monitors were used to estimate individual exposure and indoor concentration at the participant's dwelling. Background atmosphere concentrations were obtained for the AIRPARIF surveillance network. Single and multiple ANOVA were used for statistical analysis. Results: Individual exposures were low, especially for O-3 in the considered periods of time. Mean NO2 and O-3 concentrations were 41 mu g/m(3)/h and 16 mu g/m(3)/h, respectively. The NO2 individual exposure increased with the time spent in traffic and indoor concentration. The correlation coefficient between indoor and individual levels was r=0.73, and indoor concentration explained 50% of the variance in individual exposure. The sire of the dwelling with regard to high traffic street, and most strongly the presence of a gas stove influenced indoor concentration. However, mechanical air extraction decreased the mean indoor NO2 level of the dwellings. Conclusion: This study allowed identification of the environmental determinants of NO2 exposure in an urban sample. These data, together with those obtained previously, well be used to establish an exposure matrix for NO2.
Abstract: Major carotenoids in plasma-especially beta-caarotene-are affected by oxidative stress (e.g., tobacco smoking). Environmental ozone induced oxidative stress in experimental in vitro and in vivo studies, and it also increased the incidence of lung cancer in mice. We proposed to measure, after controlling for other determinants, the impact of personal ozone exposure on carotenoids levels in plasma. During the summer, we recruited 58 volunteer subjects who worked in a periurban zone. We asked each subject to wear a passive sample, which measured ozone exposure for 5 consecutive d. At the end of this period, we assessed plasma antioxidants. We observed a negative significant regression coefficient between (alpha- or beta-carotene and ozone exposure (r = -.39, p <.01, and r = -.45, p =.02, respectively). In a subsample of 45 nonsmoker subjects, among whom carotene intake was lower than the median intake value (i.e., 6.6 mg/d) of the overall group, we noted that a relatively low exposure to ozone (greater than or equal to 50 mu g/m(3).h or greater than or equal to 23.8 ppb) induced a significant decrease in plasma beta-carotene levels (i.e., 0.7 mu mol/l to 0.4 mu mol/l). This significant decrease suggested that a high dietary intake of fruit or vegetables can have a beneficial influence on the levels of plasma antioxidants generated in response to ozone exposure.
Abstract: We conducted a cross-sectional epidemiological study to evaluate personal exposure to nitrogen dioxide and its effect on blood antioxidants. Personal exposure of 107 volunteers was assessed for 14 d with passive monitors. We excluded heavy smokers (> 10 cigarettes/d) from time study, Sociodemographic and environmental data, as well as beta-carotene intake, were recorded, We mainly attributed the mean nitrogen dioxide personal exposure (31.9 +/- 12.7 mu g/m(3) [0.017 ppm or 0.70 mu M.m(3)]) (R-2 = 0.75) to residence site in the city, time spent in urban traffic, and use of gas stoves. The correlation between nitrogen dioxide exposure and blood antioxidant concentration was weak; in addition, the correlation coefficients for men and women were inconsistent. Nonetheless, we found some evidence of an interaction between carotene intake and nitrogen dioxide exposure: a significantly lower plasma beta-carotene level was evident among subjects who consumed less than or equal to 4.5 mg/jour of carotene and who were exposed to nitrogen dioxide levels that exceeded 40 mu g/m(3) (0.021 ppm or 0.87 mu M/m(3)) of nitrogen dioxide.
Abstract: Background nitrogen dioxide (NO2) pollution levels in Montpellier were measured in the context of an assessment operation carried out by the local monitoring network (AMPADI-LR), using Palmes passive samplers. The equipment was validated by continuous measurement with automatic chemiluminescence analyzers. Measurements from representative background pollution sites and the ensuing cartographic representation provide information about local pollution data, a description of seasonal evolution and an assessment of the influence of various sources. The study may be used to define parameters for establishing an exposure index, taking into account roads with heavy traffic, which affects the distribution of NO2 over Montpellier, and meteorological factors. This is a pilot study which will subsequently be used for a more precise assessment measuring the personal exposure of inhabitants, for the purposes of a study on effects on health.
