Portable X-Ray Spectrometry to Assess Metal and Metalloid Bioconcentration in the Compost Worm Eisenia fetida Exposed to Polluted Soil.

Assessing metal bioconcentration in terrestrial organisms is essential for understanding the ecotoxicological risks associated with soil contamination. This study investigates the potential of portable x-ray fluorescence spectrometry (pXRF) as a rapid, non-destructive method for quantifying metal and metalloid bioconcentration in the compost worm Eisenia fetida following exposure to contaminated soils. Initial calibration was performed using spiked worms to establish the relationship between internal concentrations and pXRF signal response. Subsequently, E. fetida individuals were exposed to 48 contaminated soils with varying contamination profiles. After a controlled exposure period, metal and metalloid concentrations in the worms' tissues were measured using a pXRF spectrometer and inductively coupled plasma spectrometer. The results obtained by pXRF were original and demonstrate some significant relationships by comparison with internal concentrations measured with conventional elemental analysis methods. By incorporating a modeling step, the predictive capabilities of pXRF data were further validated. The findings highlight the applicability of pXRF for monitoring of metal bioconcentration in soil invertebrates, aligning with the principles of green analytical chemistry by minimizing sample destruction, analysis time, and cost. This approach offers a promising alternative to traditional laboratory methods and could significantly enhance environmental risk assessment and biomonitoring strategies for contaminated sites.