A robust assessment and treatment of selected organochlorine pesticides and heavy metals in industrial wastewater using nanoparticles: a case study in Nigeria

The discharge of non/ill-treated industrial effluent containing organochlorine pesticides (OCPs) and potentially toxic metal ions into the aquatic ecosystem has endangered both aquatic life and man. Thus, this study presents the evaluation of potentially toxic metal ions in thirteen industrial effluents sampled from five different states in Nigeria, as well as the level of OCPs content of a pesticide industry sited in Kanu State, Nigeria. The range of concentration estimated for the analyte was noticed to be higher than the recommended concentration limits for both OCPs and potentially toxic metal ions. Thus, biozinc oxide nanoparticles (BioZnONPs), zinc oxide nanoparticles (ZnONPs), and biozinc oxide-carboxymethyl cellulose nanocomposite (BioZnONPs-CMC) were fabricated and characterized using non-destructive spectroscopic techniques and a specific surface area analyzer for remediation of industrial effluents. The incorporation of nanoparticles and nanocomposites resulted in a substantial reduction in key water quality parameters, including total dissolved solids (TDS), sulfate (SO₄²⁻), electrical conductivity (EC), total phosphorus, chemical oxygen demand (COD), chloride (Cl⁻), and pH, highlighting their potential for effective water purification applications. The OCPs mean adsorption capacities of BioZnONPs, ZnONPs, and BioZnONPs-CMC were determined as 10.2 ± 10.182 mg g^-1, 14.2 ± 4.526 mg g^-1, and 14.2 ± 4.525 mg g^-1, respectively. Conversely, BioZnONPs, ZnONPs, and BioZnONPs-CMC exhibited strong efficacy in removing cadmium (Cd), chromium (Cr), and lead (Pb) ions from industrial effluents, underscoring their potential as effective agents for heavy metal remediation. This study shows the successful fabrication of wastewater treatment agents for the removal of OCPs and potentially toxic metal ions. To maintain a safe environment, this study also highlights the necessity of routinely evaluating both treated and untreated industrial effluents.