Keywords:Optical Coherence Tomography, Acid mine drainage
Acid mine drainage (AMD) is the most serious environmental problem faced by mining industry in the world. Due to the high acidity of the AMD, a large number of heavy metal ions are dissolved in the discharge. Remediation of AMD by plant is currently considered, but there is a lack of research on how AMD affects seed germination in plants. Optical Coherence Tomography (OCT) is a promising technology that is widely used for structural mapping. Speckles observed in OCT has the potential to map structural changes or in other words the dynamic activity within the plants. We proposed a biospeckle optical coherence tomography (bOCT) and demonstrated that the technique could monitor the changes in plant under the influence of environmental conditions[2,3,4]. In bOCT, the dynamic variation within the seed could be visualized. In this study, we apply bOCT and focus on the effect of AMD on the germination of radish seed and employed two different concentrations of 40 and 80mL/L AMD. The germination rate and the germination time were measured and compared with the biospeckle contrast images after 6h exposures of different concentrations of AMD. In this study, we employed OCT biospeckle signal to directly monitor the effects of AMD on radish seeds, and bOCT has revealed that the internal activity of radish seed exposed to AMD within only 6 hours of exposure. There was an obvious difference in biospeckle contrast according to different concentration of AMD. The seeds germination time and germination rate could be changed in different concentration of AMD. These findings have demonstrated that biospeckle optical coherence tomography could indicate biological activities. The reasons of the higher activity in seeds exposed to AMD needs further research.