PREDICTING THE LEACHABILITY OF PESTICIDES FROM SOILS USING NEAR-INFRARED REFLECTANCE

The purpose of this study was to investigate if near-infrared reflecta nce (near-IR) spectroscopy and chemometric methods can be used as a ra pid and simple procedure to predict the leachability of pesticides fro m soil samples. The intention was to replace the often tedious determi nation of a number of chemical and physical parameters used to charact erize soils. For selection of calibration samples, near-IR spectra wer e obtained for 76 different agricultural soil samples. Principal compo nent-analysis of the spectra was used to select a subset of 20 samples which were fortified with six pesticides. Extraction was performed wi th supercritical fluid extraction (SFE) or solid phase microextraction (SPME). Partial least-squares regression of the near-IR data could pr edict 76% and 77% of the matrix-analyte interactions found by the SFE and SPME methods, respectively. The results clearly indicate that near -IR can be used to characterize soils for the prediction of the leacha bility of pesticides.