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Assessing environmental exposure to pollution is a challenging task, and scientists often use distance-based or proximity indicators when field or modeled data are unavailable. Although buffers are commonly used to represent the impact of a pollution source on neighboring populations, they can result in high-exposure misclassification. Euclidean distance-based indicators offer a promising alternative, but practices vary significantly in the literature. In this study, we aimed to compare several distance-based indicators for multiple environmental contaminants in an industrial and urban area. At the population's grid cell resolution of 200 × 200 m, we compared the distance to the closest source, the average or median distance to all sources, or a restricted number of nearby sources for six types of sources (industries, railways, rail areas, roadways, road crossings, and agricultural patches) against environmental contamination data (PM10, NO2, and multimetallic contamination in lichens). Our findings revealed that the representativeness of contamination by indicators is significantly affected by the type and number of nearby sources considered. Specifically, we found that considering the distance to the nearest source or the average distance to all sources can lead to exposure misclassifications. The optimal correlation between distance indicators and pollutant levels was observed when considering 10–14 of the closest industrial sources, located within a 4.9- to 5.5-km radius. For rail areas, the optimal number was two to three sources within a 5.4- to 7.4-km radius. For main roads, intersections, and railways, the optimal number of sources varied depending on the pollutant, generally falling within a 3- to 9.4-km radius. Environmental contamination is influenced by the diversity of nearby sources, and considering only one source increases the risk of misclassification. Our results suggest that proximity models are still appropriate for study areas where the etiology of existing health effects is unclear, providing an exploratory analysis before more sophisticated research. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a highly toxic element for living organisms and is widespread in metal-contaminated soils. As organisms which can grow up on these polluted areas, plants have some protection mechanisms against Cd issues. Among the plant kingdom, the Brassicaceae family includes species which are known to be able to tolerate and accumulate Cd in their tissues. In this study, Brassica oleracea var. viridis cv "Prover" was exposed to a range of artificially Cd-contaminated soils (from 2.5 up to 20 mg kg−1) during 3, 10, and 56 days and the effects on life traits, photosynthesis activity, antioxidant enzymatic activities were studied. Metal accumulation was quantified, as well as DNA damage, by means of the comet assay and immunodetection of 8-OHdG levels. Globally, B. oleracea was relatively tolerant to those Cd exposures. However, comet assay and detection of 8-OHdG revealed some DNA damage but which are not significant. According to metal accumulation analysis, B. oleracea var. viridis cv Prover could be a good candidate for alternative growing in contaminated areas. [ABSTRACT FROM AUTHOR]

The rapid industrialization and urbanization of intra- and peri-urban areas at the world scale are responsible for the degradation of the quality of edible crops, because of their contamination with airborne pollutants. Their consumption could lead to serious health risks. In this work, we aim to investigate the phytotoxicity induced by foliar transfer of atmospheric particles of industrial/urban origin. Leaves of cabbage plants (Brassica oleracea var. Prover) were contaminated with metal-rich particles (PbSO4 CuO and CdO) of micrometer size. A trichloroacetic acid (TCA) treatment was used to inhibit the synthesis of the epicuticular waxes in order to investigate their protective role against metallic particles toxicity. Besides the location of the particles on/in the leaves by microscopic techniques, photosynthetic activity measurements, genotoxicity assessment, and quantification of the gene expression have been studied for several durations of exposure (5, 10, and 15 days). The results show that the depletion of epicuticular waxes has a limited effect on the particle penetration in the leaf tissues. The stomatal openings appear to be the main pathway of particles entry inside the leaf tissues, as demonstrated by the overexpression of the BolC.CHLI1 gene. The effects of particles on the photosynthetic activity are limited, considering only the photosynthetic Fv/Fm parameter. The genotoxic effects were significant for the contaminated TCA-treated plants, especially after 10 days of exposure. Still, the cabbage plants are able to implement repair mechanisms quickly, and to thwart the physiological effects induced by the particles. Finally, the foliar contamination by metallic particles induces no serious damage to DNA, as observed by monitoring the BolC.OGG1 gene. [ABSTRACT FROM AUTHOR]

Real-time quantitative PCR is nowadays a standard method to study gene expression variations in various samples and experimental conditions. However, to interpret results accurately, data normalization with appropriate reference genes appears to be crucial. The present study describes the identification and the validation of suitable reference genes in Brassica oleracea leaves. Expression stability of eight candidates was tested following drought and cold abiotic stresses by using three different softwares (BestKeeper, NormFinder and geNorm). Four genes ( BolC.TUB6, BolC.SAND1, BolC.UBQ2 and BolC.TBP1) emerged as the most stable across the tested conditions. Further gene expression analysis of a drought- and a cold-responsive gene ( BolC.DREB2A and BolC.ELIP, respectively), confirmed the stability and the reliability of the identified reference genes when used for normalization in the leaves of B. oleracea. These four genes were finally tested upon a benzene exposure and all appeared to be useful reference genes along this toxicological condition. These results provide a good starting point for future studies involving gene expression measurement on leaves of B. oleracea exposed to environmental modifications. [ABSTRACT FROM AUTHOR]

The purpose of this research is to present toxic effects of some heavy metals (cadmium, lead and zinc) on lichen physiology. In the North of France, those metals are concentrated for example in industrial polluted soils near metallurgic plants and waste dumps. Our investigations were conducted on Diploschistes muscorum (Scop.) R. Sant, a terricolous lichen growing on previously quoted soils as well as on non-contaminated ones. Different stress parameters were investigated as potassium leakage – which is related to the loss of membrane integrity – and oxidative stress through following parameters: malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD). It seems, therefore, that heavy metals induce oxidative stress in this lichen, in which we found membrane damage and enhancement of SOD activity and GSH concentrations. With regard to very high concentrations of Cd, Pb and Zn, a resistance involving antioxidant mechanisms limits the expected damage. Those mechanisms involve GSH, SOD as well as secondary metabolites, which have this resistance property. This study is a first step of investigation to use – in the future – physiological parameters as tool for environment assessment. [ABSTRACT FROM AUTHOR]

The impact on the environment of Cd, Pb and Zn emissions from the A1 motorway, one of the busiest in France, was based on a simultaneous analysis of lichens, fungi and soil. The study was conducted in 12 rest areas located along a 55 km stretch of the motorway. Cd, Pb and Zn concentrations in the top soil horizon (0–10 cm) largely exceeded their concentrations at the control site. The Cd-, Pb- and Zn levels in fruiting bodies of fungi Armillaria mellea, Coprinus comatus, Marasmius oreades and Paxillus involutus were highly variable between sites. The contamination degree of transplanted thalli of Parmelia caperata was well correlated to the cumulated traffic on the western side. On the eastern side, heavy metals originated from the traffic but also from neighbouring sources (urbanization and agricultural practices). Although lead levels are decreasing, leaded petrol is still on offer and lead remains an indicator of vehicle pollution. [ABSTRACT FROM AUTHOR]