Laser Induced Fluorescence to Study the Response of Moss to Contaminant Exposure

Abstract:

The project utilizes moss to develop a non-destructive technique for detecting contaminant exposure. Moss has long been used as an environmental gauge of metal pollution due to its ability to capture atmospherically transported contaminants. A dual methodology is currently applied to observe and quantify physiological changes, using copper as a first step in methodology development. Part one doses moss with metal solutions (CuCl­₂) of different concentrations in controlled laboratory and environmental conditions and uses sequential extraction to determine surface, extra- and intracellular deposition of copper in moss over time. Part two documents physiological response of treatments using a Nd:Yag pulsed laser (Biolaser) with a compact color CMOS camera. The Biolaser is composed of a green 355nm laser and a UV 532nm laser used in tandem that can also be used individually with the application of a filter. The camera captures a red-green-blue (RGB) spectrum of the laser induced fluorescence of treated and untreated moss. Moss frond samples are selected and photographed using the Biolaser and the images interpreted using RGB data analysis. Evaluation of treated and untreated samples is accomplished by normalizing and comparing treated samples to untreated samples. Data analysis protocols of the images are being developed to quantify differences between treatment levels, natural background variations, and to determine the method’s sensitivity.