Determination of changes in leaf and canopy spectra of plants grown in soils contaminated with petroleum hydrocarbons

摘要

Changes in vegetation near pipelines are symptomatic of petroleum hydrocarbon leakages, particularly diesel and gasoline, which are fuels regularly transported onshore. The investigation of such changes in leaf and canopy spectra of vegetation grown on contaminated soils is the goal of this work. A real scale experiment was installed in an area of 2000 m(2). Two planting plots were firstly contaminated on a controlled style with diesel (6.25 L/m(3) soil) and gasoline (8.33 L/m(3) soil). A third plot was used as a control and preserved with no contaminants. Subsequently, maize, brachiaria and perennial soybean were planted on all plots. Visible and infrared spectral measurements of leaf and canopy targets were taken, respectively, between 28-184 days and 49-203 days after planting. The spectra of contaminated plants were compared to those of healthy plants. Significant differences were observed in the chlorophyll absorption feature and red edge position both at the canopy level. Narrowband spectral indices highlighted differences predominantly in plants affected by gasoline. The evident changes in the canopy spectra show that the hydrocarbons damaged the canopy structure extensively. The spectral patterns revealed here have important implications for detecting and monitoring areas likely contaminated with liquid HCs using hyperspectral remote sensing.