Office National D'Études Et de Recherches Aérospatiales (ONERA), Toulouse, France.
TOTAL S.A., Pôle D'Études Et de Recherches de Lacq, Lacq, France.
Sci Rep. 2021 Jan 7;11(1):2. doi: 10.1038/s41598-020-79439-z.
Monitoring plant metal uptake is essential for assessing the ecological risks of contaminated sites. While traditional techniques used to achieve this are destructive, Visible Near-Infrared (VNIR) reflectance spectroscopy represents a good alternative to monitor pollution remotely. Based on previous work, this study proposes a methodology for mapping the content of several metals in leaves (Cr, Cu, Ni and Zn) under realistic field conditions and from airborne imaging. For this purpose, the reflectance of Rubus fruticosus L., a pioneer species of industrial brownfields, was linked to leaf metal contents using optimized normalized vegetation indices. High correlations were found between the vegetation indices exploiting pigment-related wavelengths and leaf metal contents (r ≤ - 0.76 for Cr, Cu and Ni, and r ≥ 0.87 for Zn). This allowed predicting the metal contents with good accuracy in the field and on the image, especially Cu and Zn (r ≥ 0.84 and RPD ≥ 2.06). The same indices were applied over the entire study site to map the metal contents at very high spatial resolution. This study demonstrates the potential of remote sensing for assessing metal uptake by plants, opening perspectives of application in risk assessment and phytoextraction monitoring in the context of trace metal pollution.
监测植物对金属的吸收对于评估污染场地的生态风险至关重要。虽然传统的技术通常用于实现这一目标，但破坏性较大，而可见近红外（VNIR）反射光谱代表了一种远程监测污染的良好替代方法。基于先前的工作，本研究提出了一种在实际田间条件下和从航空成像中绘制叶片中几种金属（Cr、Cu、Ni 和 Zn）含量的方法。为此，利用优化的归一化植被指数将工业棕地先锋物种悬钩子属植物的反射率与叶片金属含量联系起来。结果表明，利用与色素相关波长的植被指数与叶片金属含量之间存在高度相关性（Cr、Cu 和 Ni 的 r 值≤-0.76，Zn 的 r 值≥0.87）。这使得在田间和图像上都可以很好地预测金属含量，尤其是 Cu 和 Zn（r 值≥0.84 和 RPD 值≥2.06）。同样的指数也应用于整个研究区域，以非常高的空间分辨率绘制金属含量图。本研究证明了遥感在评估植物金属吸收方面的潜力，为在痕量金属污染背景下进行风险评估和植物提取监测的应用开辟了前景。
