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.

The effects of various factors including turbidity, pH, DOC, temperature, and solar radiation on the concentrations of total mercury (TM) and dissolved gaseous mercury (DGM) were investigated in an artificial reservoir in Korea. Episodic total mercury accumulation events occurred during the rainy season as turbidity increased, indicating that the TM concentration was not controlled by direct atmospheric deposition. The DGM concentration in surface water ranged from 3.6 to 160 pg/L, having a maximum in summer and minimum in winter. While in most previous studies DGM was controlled primarily by a photo-reduction process, DGM concentrations tracked the amount of solar radiation only in winter when the water temperature was fairly low in this study. During the other seasons microbial transformation seemed to play an important role in reducing Hg(II) to Hg(0). DGM increased as dissolved organic carbon (DOC) concentration increased (p-value < 0.01) while it increased with a decrease of pH (p-value < 0.01). Long-term in-situ monitoring of TM and DGM concentrations with various factors was executed in a large artificial reservoir in this study.

We investigated lichen diversity in temperate oak forests using standardized protocols. Forty-eight sites were sampled in the Czech Republic, Slovakia and Hungary. The effects of natural environmental predictors and human influences on lichen diversity (lichen diversity value, species richness) were analysed by means of correlation tests. We found that lichen diversity responded differently to environmental predictors between two regions with different human impact. In the industrial region, air pollution was the strongest factor. In the agricultural to highly forested regions, lichen diversity was strongly influenced by forest age and forest fragmentation. We found that several natural factors can in some cases obscure the effect of human influences. Thus, factors of naturality gradient must be considered (both statistically and interpretively) when studying human impact on lichen diversity. We detected the different responses of lichens to ecological predictors in polluted and unpolluted areas.

Anthropogenic trace element emissions have declined. However, top soils all over the world remain enriched in trace elements. We investigated Pb and Cd migration in forest soils of a remote monitoring site in the Austrian limestone Alps between 1992 and 2004. Large spatial variability masked temporal changes in the mineral soil of Lithic Leptosols (Skeltic), whereas a significant reduction of Pb concentrations in their forest floors occurred. Reductions of concentrations in the less heterogeneous Cambisols (Chromic) were significant. In contrast, virtually no migration of Pb and Cd were found in Stagnosols due to their impeded drainage. Very low element concentrations (<1 μg l−1) in field-collected soil solutions using tension lysimeters (0.2 μm nylon filters) imply that migration largely occurred by preferential flow as particulate-bound species during intensive rainfall events. Our results indicate that the extent of Pb and Cd migration in soils is largely influenced by soil type. Comparison between soil solid phase and soil solution concentrations imply that trace element migration largely occurred by preferential flow as particulate-bound species.

Arable soils are a significant source of nitric oxide (NO), a precursor of tropospheric ozone, and thereby contribute to ozone pollution. However, their actual impact on ozone formation is strongly related to their spatial and temporal emission patterns, which warrant high-resolution estimates. Here, we combined an agro-ecosystem model and geo-referenced databases to map these sources over the 12 000 km2 administrative region surrounding Paris, France, with a kilometric level resolution. The six most frequent arable crop species were simulated, with emission rates ranging from 1.4 kg N–NO ha−1 yr−1 to 11.1 kg N–NO ha−1 yr−1. The overall emission factor for fertilizer-derived NO emissions was 1.7%, while background emissions contributed half of the total NO efflux. Emissions were strongly seasonal, being highest in spring due to fertilizer inputs. They were mostly sensitive to soil type, crops' growing season and fertilizer N rates. The use of an agro-ecosystem model at regional scale makes it possible to map the emissions of nitric oxide from arable soils at a resolution compatible with tropospheric ozone models.

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED [Axe_IRSTEA]TED-EPURE | International audience | This paper presents the key elements that emerged from a 3-year study on 4 campsites. Each of them has its own Vertical-Flow Constructed Wetlands (VFCW) for on-site wastewater treatment. Each year, the pollution discharge peaked in the 5 to 6-week summer period but was zero for a 6-month period. The natural-concentrate wastewater is collected into a short sewer network. Hydraulic load and campground occupancy rate were tightly correlated. The effluent has a characteristically high nitrogen concentration due to the lower greywater-producing activity. These quantitative and qualitative elements were used to define the camper equivalent' as a daily pollutant load of about 100 L water, 90 gCOD, 35 gBOD5, 40 gSS, 11 gKN and 1.4 gPt. During the 5-6 weeks of peak visitor traffic, the full first stage receives an organic load of 200 gCOD.m-2.d-1 and 25 gKN.m-2.d-1, which is 2 to 3.5-fold higher than the loads conventionally applied in VFCW systems in France. Despite these heavy loads, COD removal remains constant (at 91%) over the season. During the summer peak, nitrification drops sharply but KN removal rate holds steady near 60%. This study demonstrates that VFCWs can robustly handle massive load increases. The paper concludes that total system size can be downscaled to 0.75 m²/camper. This design allows to reach minimum yields of 75% KN, provided that the system is built and run to state-of-the-art rules. | Cet article présente les éléments clés issus d'une étude de 3 ans sur 4 campings qui traitent leurs eaux usées de manière individuelle par des Filtres Plantés de Roseaux à écoulement vertical (FPRV) aux dimensionnements différents. La charge hydraulique et le taux d'occupation du camping sont étroitement corrélés. L'émission est nulle 6 mois par an et la pointe estivale dure 5 à 6 semaines. Les eaux usées, collectées par un réseau court sont naturellement concentrées. L'effluent présente notamment une très forte concentration en azote du fait d'une activité ménagère réduite. Ces éléments qualitatifs et quantitatifs permettent de définir l' « équivalent campeur » par une charge de pollution journalière d'environ 100 L d'eau, 90 g de DCO, 35 g de DBO5, 40 g de MES, 11 g de NK et 1,4 g de Pt. Au cours des 5-6 semaines de fréquentation maximale, la totalité du 1er étage reçoit une charge organique d'environ 200 gDCO.m-².j-1 et 25 gNK.m-².j-1, soit 2 à 3,5 fois plus que les charges classiques appliquées en FPRV en France. En dépit de ces fortes charges, l'élimination de la DCO reste constante (91 %) au cours de la saison. Lors du pic de fréquentation estival, la nitrification décroît fortement mais le rendement global se maintient à environ 60 %. La robustesse des FPRV face à une augmentation massive des charges appliquées est démontrée. L'article conclut par un dimensionnement réduit de 0.75 m2/campeur au total. Ce dimensionnement permet d'atteindre un rendement minimum de 75 % du NK, correspondant à la nitrification, sous réserve que les règles de l'art de construction et d'exploitation soient strictement respectées.

There is currently a lack of ecotoxicity tests adapted to earthworm species of higher ecological relevance and whose endpoints could be directly related to their ecological role in the soil. We propose a new and relatively simple ecotoxicity test based on the estimation of cast production (CP) by Lumbricus terrestris under laboratory conditions. CP was found to be linearly correlated to earthworm biomass and to be greatly influenced by soil water content. Azinphos-methyl had no effect on CP at all the concentrations tested. Significant decreases were observed at the normal application rate for other pesticides with (imidacloprid, carbaryl, methomyl) or without (ethyl-parathion and chlorpyrifos-ethyl) a clear concentration–effect response. For the highest concentration tested, reduction in CP varied between 35 and 67%. CP is straightforward and rapidly measured and ecologically meaningful. We thus believe it to be of great use as an endpoint in ecotoxicity testing. Cast production of Lumbricus terrestris is affected by pesticides under laboratory conditions.

Mecoprop, dichlorprop and metolachlor concentrations and enantiomer signatures were determined in Ontario streams in 2006-2007 and compared to results from 2003 to 2004. Median concentrations of dichlorprop and metolachlor were not significantly different between the two campaigns, but mecoprop was higher in 2006-2007. Concentrations of mecoprop and dichlorprop in Lake Ontario surface water were 1-2 orders of magnitude lower than stream averages. Enantiomer fractions (EFs) > 0.5 of mecoprop in high-concentration stream water samples during 2006-2007 were related to replacement of racemic mecoprop by single (+) enantiomer mecoprop-P after 2004. EFs <0.5 in low-concentration samples suggested enantioselective degradation and/or interconversion. Metolachlor profiles were expressed as SF, the fraction of herbicidally active/(active + inactive) stereoisomers. Samples with higher concentrations of metolachlor had SFs similar to S-metolachlor which is enriched in the active stereoisomers. Low concentrations were associated with lower and more variable SFs, suggesting mixed input of racemic and S-metolachlor or stereoselective degradation.

Mercury (Hg) concentration was investigated for 127 urban soil samples collected from business area (BA), classical garden (CG), culture and education area (CEA), public green space (PGS), residential area (RA) and roadside area (RSA) in Beijing. The median of Hg concentration in Beijing was 0.26 mg/kg. The value in CG was much higher than the other 5 types of land use, which was due to the historical use of Hg. More than 87% of the samples were not contaminated according to the guideline values of China, UK, Canada, and USEPA. Spatial distribution map revealed that Hg concentration showed a decreasing trend from the center to the suburb, it increased with the age of the urban area. Hg contamination in urban area of Beijing is marked by features of non-point sources associated with human activities, and it is most likely to be the common characteristics of Hg contamination in cities. Hg distribution in Beijing was affected by both types of land use and the age of urban area.

Chars were generated by pyrolyzing pine wood at temperatures between 300 °C and 700 °C for 6 h and at 500 °C for 10–300 min. Their organic content and surface acidity decreased, and BET surface area increased, with increasing pyrolytic temperature and time. The uptake of benzene and nitrobenzene increased with increasing pyrolytic temperature and time with isotherms characterized by a transition from less to more concave-downward. The isotherms with low-temperature and short-time chars were fitted to the dual Langmuir-partition model, whereas those with high-temperature chars to the dual-Langmuir model. Calculations suggest that the organic phases of chars functioned as partition media and the uptake of benzene and nitrobenzene on carbonized chars occurred first in micropores via pore-filling and later in larger pores through capillary condensation and adsorption. It is concluded that chars may be considered to consist of the partition domain, the high-energy micropores domain and the low-energy large pores domain. Pine chars consist of the partition domain, the micropores domain and the large pores domain in terms of organic contaminant uptake.