Application of portable XRF and VNIR sensors for rapid assessment of soil heavy metal pollution

Rapid heavy metal soil surveys at large scale with high sampling density could not be con-ducted with traditional laboratory physical and chemical analyses because of the high cost, lowefficiency and heavy workload involved. This study explored a rapid approach to assess heavymetals contamination in 301 farmland soils from Fuyang in Zhejiang Province, in the southernYangtze River Delta, China, using portable proximal soil sensors. Portable X-ray fluorescencespectroscopy (PXRF) was used to determine soil heavy metals total concentrations while soil pHwas predicted by portable visible-near infrared spectroscopy (PVNIR). Zn, Cu and Pb were suc-cessfully predicted by PXRF (R2 >0.90 and RPD >2.50) while As and Ni were predicted with lessaccuracy (R2 <0.75 and RPD