Essential Trace Elements in the Shells of Commercial Mollusk Species from the Black Sea and Their Biotechnological Potential

Among the commercial mollusks from the Black Sea, the ark clam <i>Anadara kagoshimensis</i>, the oyster <i>Crassostrea gigas</i>, the mussel <i>Mytilus galloprovincialis</i>, the scallop <i>Flexopecten glaber ponticus</i>, and the gastropod <i>Rapana venosa</i> hold the top positions in terms of cultivation and harvesting volumes. Mollusk shells are attracting attention due to their potential use in various biotechnological applications, including nutraceutical production. In the present study, using inductively coupled plasma mass spectrometry, concentrations of essential trace elements (Cr, Mn, Fe, Co, Cu, Zn, Se, Mo, and I) were measured in shells of the five mollusks sampled from the same biotope. The essential element concentrations in the mollusk shells differed significantly. The highest concentrations of Cr, Mn, and I were found in <i>Anadara</i> shells; Fe and Co in <i>Crassostrea</i> shells; Zn in <i>Mytilus</i> shells; and Cu and Se in <i>Rapana</i> shells. Principal component analyses demonstrated the overall accumulation of all elements as the main cause of the total data variance and the species-specific accumulation of certain elements as the second most important source of the data dispersion. Matrices of element concentration correlations showed considerable dissimilarity, which suggested species specificity in the concerted or competing element accumulation. Powdered shells of <i>Anadara</i>, <i>Crassostrea</i>, and <i>Rapana</i> are most suitable to fulfill the daily human requirements for many essential elements, and the consumption of these powders in amounts of less than a few tens of grams appears to be sufficient for this purpose.