Quantitative Assessment of Carcinogenic and Non-Carcinogenic Risks of Heavy Metal Exposure Among Adults and Children at Katsina Youth Craft Village, Nigeria

Abstract

Despite growing evidence of heavy metal toxicity in occupational environments, data on exposure risks among young vocational trainees and ambient child populations in northern Nigeria remain scarce. This study investigated the concentrations and associated health hazards of cobalt, chromium, lead, cadmium, and copper in soils from the Youth Craft Village, Katsina. Elemental concentrations were determined using Flame Atomic Absorption Spectrophotometry (FAAS). Among the heavy metals detected, chromium recorded the highest mean concentration, followed by cobalt, copper, lead, and cadmium in descending order, with respective values of 0.608 ± 0.660, 0.225 ± 0.0531, 0.105 ± 0.297, 0.0382 ± 0.0265, and 0.00431 ± 0.00310 mg/kg, which are below the WHO/FAO permissible limits (Cr: 43.4; Co: 5.00; Cu: 31.6; Pb: 35.8; Cd: 0.99 mg/kg). Hierarchical cluster analysis (HCA) reveals automobile mechanics activities and construction materials as the most dominant source of pollution in the area. Hazard Index (HI) and Hazard Quotient (HQ) estimates across ingestion, inhalation, and dermal exposure pathways were below unity for both adults and children, indicating that non-carcinogenic hazards associated with heavy metal exposure remained within acceptable limits. Assessment of carcinogenic risk indicated that chromium exposure resulted in mean total lifetime cancer risks (TLCR) of 4.01 × 10⁻⁶ for children, exceeding the USEPA acceptable threshold (1.0 × 10⁻⁶). These elevated risks, particularly for children population, underscore the imperative for environmental monitoring and public health interventions to reduce chronic exposure due to heavy metals present in the environment.