Activated carbon (AC) can help overcome toxicity of pollutants to microbes and facilitate soil bioremediation. We used this approach to treat a Histosol and an Alluvial soil historically contaminated with PCB (4190 and 1585 mg kg−1, respectively; primarily tri-, tetra- and pentachlorinated congeners). Results confirmed PCB persistence; reductions in PCB extractable from control and AC-amended soils were mostly due to a decrease in tri- and to some extent tetrachlorinated congeners as well as formation of a bound fraction. Mechanisms of PCB binding by soil and AC were different. In addition to microbial degradation of less chlorinated congeners, we postulate AC catalyzed dechlorination of higher chlorinated congeners. A large decrease in bioavailable PCB in AC-amended soils was demonstrated by greater clover germination and biomass. Phytotoxicity was low in treated soils but remained high in untreated soils for the duration of a 39-month experiment. These observations indicate the utility of AC for remediation of soils historically contaminated with PCB. Activated carbon promotes remediation of soils historically contaminated with PCB.

This study has evaluated urban habitat quality by studying specific leaf area (SLA) and stomatal characteristics of the common herb Plantago lanceolata L. SLA and stomatal density, pore surface and resistance were measured at 169 locations in the city of Gent (Belgium), distributed over four land use classes, i.e., sub-urban green, urban green, urban and industry. SLA and stomatal density significantly increased from sub-urban green towards more urbanised land use classes, while the reverse was observed for stomatal pore surface. Stomatal resistance increased in the urban and industrial land use class in comparison with the (sub-) urban green, but differences between land use classes were less pronounced. Spatial distribution maps for these leaf characteristics showed a high spatial variation, related to differences in habitat quality within the city. Hence, stomatal density and stomatal pore surface are assumed to be potentially good bio-indicators for urban habitat quality. Stomatal characteristics of Plantago lanceolata can be used for biomonitoring of urban habitat quality.

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED [Axe_IRSTEA]TED-EPURE | International audience | On the 2006 IWA International Wetlands Conference in Portugal, two wetland pilot plants in the small tropical island of Mayotte, in the Indian Ocean, were presented. The first pilot plant being a vertical flow filter with recirculation, fed with raw sewage, and the second one a horizontal flow filter after an Imhoff tank. These plants where put into operation the end of 2005 and early 2006, respectively, by SIEAM, which is a syndicate created by the islands authorities who will have the task to operate all water and sewage equipment on the island. The plants have been monitored by SIEAM ever since they went into operation and first results were presented at the 2006 Wetlands conference. In this paper, we present the operation conditions, treatment results and problems encountered during the last 4 years of operation and monitoring of these pilot plants, which will be of particular interest in the aim of finding sustainable treatment solutions for small communities in the tropics, even though the amount of date gathered during this four year period is not as important as we had hoped.

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International audience

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED [Axe_IRSTEA]TED-EPURE | International audience | Thus, choosing to plant local macrophytes species in CWs can be considered as an asset for the development of CWs, since it can be a part of global development projects which integrate cultural, social and economic characteristics. But, because of the ability of some macrophytes to accumulate toxic elements, human utilisation of CWs macrophytes has to be managed considering health damage potentiality. Spontaneous macrophytes diversity has to be appreciated for its key-role in the development of CWs in developing countries, not only from an ecological point of view, but also from cultural, social, sanitary and economic views.

The effects of elevated concentrations of atmospheric tropospheric ozone (O3) on DNA damage in five trembling aspen (Populus tremuloides Michx.) clones growing in a free-air enrichment experiment in the presence and absence of elevated concentrations of carbon dioxide (CO2) were examined. Growing season mean hourly O3 concentrations were 36.3 and 47.3 ppb for ambient and elevated O3 plots, respectively. The 4th highest daily maximum 8-h ambient and elevated O3 concentrations were 79 and 89 ppb, respectively. Elevated CO2 averaged 524 ppm (+150 ppm) over the growing season. Exposure to O3 and CO2 in combination with O3 increased DNA damage levels above background as measured by the comet assay. Ozone-tolerant clones 271 and 8L showed the highest levels of DNA damage under elevated O3 compared with ambient air; whereas less tolerant clone 216 and sensitive clones 42E and 259 had comparably lower levels of DNA damage with no significant differences between elevated O3 and ambient air. Clone 8L was demonstrated to have the highest level of excision DNA repair. In addition, clone 271 had the highest level of oxidative damage as measured by lipid peroxidation. The results suggest that variation in cellular responses to DNA damage between aspen clones may contribute to O3 tolerance or sensitivity. Ozone tolerant clones and sensitive Populus tremuloides clones show differences in DNA damage and repair.

In 2006, a controlled infection study was performed in the ‘Kranzberger Forst’ to address the following questions: (1) Will massive artificial inoculation with Apiognomonia errabunda override the previously observed inhibitory effect of chronic ozone? (2) Can biochemical or molecular markers be detected to account for the action of ozone? To this end six adult beech trees were chosen, three ozone fumigated (2× ozone) and three control trees (ambient = 1× ozone). Spore-sprayed branches of sun and shade crown positions of each of the trees, and uninoculated control branches, were enclosed in 100-L plastic bags for one night to facilitate infection initiation. Samples were taken within a five-week period after inoculation. A. errabunda infestation levels quantified by real-time PCR increased in leaves that were not fumigated with additional ozone. Cell wall components and ACC (ethylene precursor 1-amino cyclopropane-1-carboxylic acid) increased upon ozone fumigation and may in part lead to the repression of fungal infection. Chronic sublethal ozone exposure reduces both natural and artificial infestation of beech leaves by the endophytic fungus Apiognomonia errabunda.

Landfill leachates usually need to be treated before discharged, and using soil–plant systems for this has gained substantial interest in Sweden and in the UK. A three-year field study was conducted in central Sweden to quantify plant response, treatment efficiency and impact on groundwater quality of landfill leachate irrigation of short-rotation willow coppice (Salix). Two willow varieties were tested and four irrigation regimes in sixteen 400-m2 plots. The willow plants did not react negatively, despite very high annual loads of nitrogen (≤2160 kg N/ha), chloride (≤8600 kg Cl/ha) and other elements. Mean annual growth was 1.5, 9.8 and 12.6 tonnes DM/ha during years 1–3. For one of two willow varieties tested, relative leaf length accurately predicted growth rate. Irrigation resulted in elevated groundwater concentrations of all elements applied. Treatment efficiency varied considerably for different elements, but was adequate when moderate loads were applied. Short-rotation willow coppice was successfully used for treating a strong landfill leachate in central Sweden over three years.

In this study, we measured via surgical sampling hepatic EROD activity in yellow-legged gulls from oiled and unoiled colonies, 17 months after the Prestige oil spill. We also analyzed stable isotope composition in feathers of the biopsied gulls, in an attempt to monitor oil incorporation into marine food web. We found that yellow-legged gulls in oiled colonies were being exposed to remnant oil as shown by hepatic EROD activity levels. EROD activity was related to feeding habits of individual gulls with apparent consequences on delayed lethality. Capture-recapture analysis of biopsied gulls suggests that the surgery technique did not affect gull survival, giving support to this technique as a monitoring tool for oil exposure assessment. Our study highlights the combination of different veterinary, toxicological and ecological methodologies as a useful approach for the monitoring of exposure to remnant oil after a large oil spill.