This research focuses on the analysis, fate, and effects of essential and toxic trace elements in food, feed, and the environment. The work primarily focuses on studying the factors influencing speciation—i.e., the chemical forms in which trace elements occur—and their impact on the fate of these elements in food/feed and the natural and agricultural environments. Special attention is given to micronutrient biofortification, which involves enriching foodstuffs with essential trace elements (e.g., zinc, selenium, and iodine). Moreover, factors that affect the bioavailability and species transformations of trace elements in the intestine are studied. Another research line focuses on the development of technologies for the removal and recovery of toxic and valuable trace elements from liquid and solid wastes, with also particular attention given to the role of speciation.