Assessment of Heavy Metal Contamination and their Pollution Index in Settled Dust from Kaduna Polytechnic Campuses, Kaduna State, Nigeria

The concentration, distribution, and ecological risk associated of selected heavy metals (Zn, Cd, Pb, Ni, and Cr) in indoor dust samples across the four colleges at Kaduna Polytechnic which includes College of Administration and Social Science (CASSS), College of Environmental Studies (CES), College of Science and Technology (CST), and College of Business and Management Studies (CBMS).  Low to moderate concentrations of heavy metals were observed in CASSS, CES, and CBMS confirming their mostly non-industrial and administrative activities. Higher concentrations were observed in CST, this may likely be attributed to laboratory based and technical operations involving reagents, equipments, and experimental procedures. However, Zn and Pb indicated notable variability, while Cd concentration remain consistently low whereas approached limits in some cases. The comparative analysis of the heavy metals with WHO/FAO and US EPA standards indicated that all measured concentrations were within acceptable limits, though cadmium requires continuous monitoring due to its toxicity. Statistical analysis demonstrated significant anthropogenic contributions to metal accumulation in selected sites. The Contamination factor (Cf) and pollution load index (PLI) assessment have shown localized hotspots, particularly at DAP, DAB, and DA, with different levels of ecological risk varying from moderate to very high contamination. Overall, while current pollution levels suggest low immediate health risk, the presence of anthropogenic influences and potential for long-term accumulation highlight the need for periodic monitoring and improved environmental management practices.