Use of certain natural polymers to reduce the toxic effects of lead ions on biological objects

BACKGROUND: The wide use of lead compounds in electrical engineering, dye production, insecticides, and in the manufacture and use of ammunition has led to its negative impact on the environment and the human body. Lead levels increase as a result of military operations, which is relevant today, because of its use in ammunition. During explosions or shots, ammunition releases lead as particles and vapor that can contaminate water, soil, and air, entering the upper respiratory tract of humans. Although there are currently a significant number of eco- and enterosorbents, most of the latter are based primarily on silicon dioxide, lignin, smectites, etc. These materials are not always specifically effective against heavy metals. Consequently, there is an urgent need to address two key challenges: immobilizing pollutants to remove them from geochemical flows, and developing preventive and therapeutic measures to detoxify individuals living or working in areas with adverse industrial exposure.

AIM: This work aimed to analyze and comparatively evaluate the sorption activity of humic acids and ground reindeer antlers with known enterosorbents against lead ions at pH 3.

METHODS: Biopolymer samples (humic acids and reindeer antler tissue) were selected as study objects. Colloidal silicon dioxide (Polysorbâ) and hydrolyzed lignin (Filtrum-STIâ) were used as standard reference enterosorbents. Direct potentiometry and infrared spectroscopy were used in the study.

RESULTS: Sorbents derived from natural raw materials (humic acids and reindeer antler tissue) demonstrated sufficiently high sorption activity toward lead ions and strength of binding according to the calculated sorption capacity constant and binding capacity coefficient, respectively. The bone tissue of reindeer antlers exhibited higher values of sorbent–sorbate affinity coefficients and Pb²⁺ absorption rate compared with other sorbents. The recorded infrared spectra of biopolymer samples had qualitatively similar absorption peaks; however, the quantitative content of functional groups within their molecules differed.

CONCLUSION: The studied biopolymers (humic acids and reindeer antler tissue) exhibit high sorption properties toward lead ions, significantly exceeding those of enterosorbents already available on the pharmaceutical market. The implementation of high sorption characteristics of the examined natural biopolymers and their ability to participate in heavy metal ion binding through chelation likely relates to the features of their structural-functional organization.