Innovative Ultrasound-Assisted Approaches towards Reduction of Heavy Metals and Iodine in Macroalgal Biomass

The aim of this work was to evaluate the potential of ultrasound (US), alone or in combination with mild heating and/or EDTA towards reduction of As, Cd, I, and Hg content of Laminaria hyperborea. Concentrations of As, Cd, I, and Hg of 56.29, 0.596, 7340, and <0.01 mg kg(-1) of dry weight, respectively, were found in L. hyperborea blades. Treatment with US at 50 degrees C increased approx. 2-fold the amount of As released, although did not affect significantly the content of Cd or I, as compared to control (no US) samples. Reducing the temperature to 8 degrees C significantly decreased the effect of US, but heating at 80 degrees C did not cause a significant effect as compared to treatments at 50 degrees C. On the other hand, treatment with 0.1 N EDTA at 50 degrees C enhanced the percentage of Cd released by approximately 7-fold, regardless of sonication. In the present work, the combination of US and EDTA at 50 degrees C for 5 min led to a significant reduction of the As (32%), Cd (52%) and I (31%) content in L. hyperborea, thus improving the product's safety for consumers.

Automated summary

The study demonstrates that the combination of ultrasound and EDTA at 50 degrees Celsius for 5 minutes can significantly reduce the content of arsenic, cadmium, and iodine in Laminaria hyperborea, improving product safety for consumers.