Analysis of selected heavy metals (Fe, Pb, Cu, Cr) in surface water and sediments in Okulu River in Eleme Local Government Area of Rivers State Nigeria. Humanities Horizon, [S. l.], v. 3, n. 1, p. 16–29, 2026. DOI: 10.63373/3047-8014/49. Disponível em: https://journal.penapro.org/index.php/hh/article/view/49. Acesso em: 2 jun. 2026.