Terahertz spectroscopy-based rapid detection of exchangeable heavy metal pollution in soil using Scenedesmus obliquus

This study introduces a novel approach for the rapid detection of exchangeable heavy metal pollution in soil, utilizing Scenedesmus obliquus as a bioadsorbent. Terahertz spectroscopy was used to analyze the cell wall proteins and functional groups of S. obliquus following physical adsorption. This analysis enabled the deduction of the types and concentrations of exchangeable heavy metal ions in soil. We established a prediction model for heavy metal concentrations using partial least squares (PLS) regression, achieving optimal detection times: 10 min for Pb 2+ , 20 min for Ni 2+ , and 30 min for Co 2+ . Validation with real surface soil samples demonstrated excellent accuracy rates: 97.8 % for Pb 2+ , 91.8 % for Ni 2+ , and 90 % for Co 2+ . Notably, our method reduces the detection time to 0.5 hours, requires only 5 ml of sample volume, and enhances detection accuracy to 0.1 μg/L.