HEAVY METAL

This study assessed heavy metal contamination and associated health risks in soils around a sand mining site in Ikpeshi, Edo State, Nigeria. Soil samples were collected at varying distances from the mine and analyzed for Fe, Zn, Cu, Pb, Cd, Mn, Ni, Cr, and Co. Results showed that most metals were below U.S. EPA limits, except Cobalt (Co). Pollution indices indicated low contamination levels overall, though Cadmium (Cd) showed moderate contamination linked to mining activities. The ecological risk index (RI = 79.11) revealed low ecological threat. Health risk assessment found negligible non-carcinogenic effects, while the Total Carcinogenic Risk (TCR) from Pb, Cd, Ni, and Cr was within the U.S. EPA acceptable range (10⁻⁶ to 10⁻⁴) for both adults and children. However, Cd and Cr contributed most to potential cancer risk. Continuous monitoring and stricter mining regulations are recommended to prevent future health hazards.

In today's world, the rise of modernization and industrialization has quietly reshaped ecosystems—the rapid expansion of industries and unchecked urbanization continue to disrupt fragile environments, leading to the persistent challenge of heavy metal contamination in soil. This study investigates the green synthesis and characterization of an MgO-MnO-biochar ternary nanocomposite as well as the MgO-MnO Nanopparticle using an eco-friendly co-precipitation method, and highlightening its potential heavy metal remediation applications. The synthesis involved the bottom- up fabrication of magnesium and manganese oxides in a green solvent system, followed by integration with biochar. The characterization of the MgO-MnO-biochar nanocomposite and MgO-MnO nanoparticle system revealed significant structural, compositional, and morphological differences. FTIR analysis showed the nanocomposite had prominent O–H stretching at 3951.1, 3641.1, and 3790.2 cm⁻¹, C–H stretching at 2907.3 cm⁻¹, CO₂ adsorption at 2110.3 cm⁻¹, C=C stretching at 1611.8 cm⁻¹, and Mg–O and Mn–O bonds at 946.3 and 864.7 cm⁻¹, while the nanoparticle system exhibited fewer functional groups, with CO₂ adsorption at 2102.2 cm⁻¹ and C=C stretching at 1598.5 cm⁻¹. EDX analysis revealed high carbon content (48.72 wt%) in the nanocomposite, absent in the nanoparticle system, alongside higher Mn (61.62 wt%) and Mg (32.24 wt%) concentrations in the nanoparticle system compared to 24.47 wt% Mn and 11.34 wt% Mg in the composite. XRD analysis identified Lindergerbite (59.00%) and Periclase (13.00%) in the nanoparticle system, while the nanocomposite featured Flagstaffite (52.40%), Graphite (1.84%), and Cryoptohalite (7.96%). BET analysis showed the nanoparticle system had a higher surface area (282.000 m²/g vs. 216.400 m²/g), pore volume (0.173 cm³/g vs. 0.128 cm³/g), and BJH surface area (354.200 m²/g vs. 265.400 m²/g), though pore diameters were similar (2.132 nm vs. 2.129 nm). SEM analysis revealed the nanocomposite's porous, fibrous structure with well-dispersed nanoparticles, while the nanoparticle system exhibited a denser, more aggregated morphology with reduced porosity. The characterization results revealed that the MgO-MnO-biochar ternary nanocomposite possesses significant structural and compositional properties, suggesting its potential as a sustainable, cost-effective material for future heavy metal remediation applications.