Vegetation reflectance spectroscopy for biomonitoring of heavy metal pollution in urban soils
2018
Yu, Kang | van Geel, Maarten | Ceulemans, Tobias | Geerts, Willem | Ramos, Miguel Marcos | Serafim, Cindy | Sousa, Nadine | Castro, Paula M. L. | Kastendeuch, Pierre | Najjar, Georges | Ameglio, Thierry | Ngao, Jérome | Saudreau, M. | Honnay, Olivier | Somers, Ben | Université Catholique de Louvain = Catholic University of Louvain (UCL) | Universidade Católica Portuguesa | Université de Strasbourg (UNISTRA) | Laboratoire de Physique et Physiologie Intégratives de l’Arbre en environnement Fluctuant (PIAF) ; Institut National de la Recherche Agronomique (INRA)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020]) | ANR-16-EBI3-0007,URBANMYCOSERVE,Understanding and Managing Urban Ectomycorrhizal Fungi Communities to Increase the Health and Ecosystem Service Provisioning of Urban Trees(2016)
International audience
显示更多 [+] 显示较少 [-]英语. Heavy metals in urban soils may impose a threat to public health and may negatively affect urban tree viability. Vegetation spectroscopy techniques applied to bio-indicators bring new opportunities to characterize heavy metal contamination, without being constrained by laborious soil sampling and lab-based sample processing. Here we used Tilia tomentosa trees, sampled across three European cities, as bio-indicators i) to investigate the impacts of elevated concentrations of cadmium (Cd) and lead (Pb) on leaf mass per area (LMA), total chlorophyll content (Chl), chlorophyll a to b ratio (Chla:Chlb) and the maximal PSII photochemical efficiency (Fv/Fm); and ii) to evaluate the feasibility of detecting Cd and Pb contamination using leaf reflectance spectra. For the latter, we used a partial-least-squares discriminant analysis (PLS-DA) to train spectral-based models for the classification of Cd and/or Pb contamination. We show that elevated soil Pb concentrations induced a significant decrease in the LMA and Chla:Chlb, with no decrease in Chl. We did not observe pronounced reductions of Fv/Fm due to Cd and Pb contamination. Elevated Cd and Pb concentrations induced contrasting spectral changes in the red-edge (690–740 nm) region, which might be associated with the proportional changes in leaf pigments. PLS-DA models allowed for the classifications of Cd and Pb contamination, with a classification accuracy of 86% (Kappa = 0.48) and 83% (Kappa = 0.66), respectively. PLS-DA models also allowed for the detection of a collective elevation of soil Cd and Pb, with an accuracy of 66% (Kappa = 0.49). This study demonstrates the potential of using reflectance spectroscopy for biomonitoring of heavy metal contamination in urban soils.
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