Occupational Exposure to Hexavalent Chromium and Respiratory Health Among Electroplating Workers in Kaduna State

Hexavalent chromium (Cr VI) is a confirmed respiratory carcinogen predominantly encountered in electroplating and surface finishing operations, yet occupational exposure monitoring and respiratory health surveillance in Nigerian electroplating facilities remain severely limited. This analytical cross-sectional study assessed Cr VI exposure levels and respiratory health outcomes among electroplating workers in Kaduna State, North West Nigeria. One hundred and eighty electroplating workers and 90 unexposed administrative controls were recruited from electroplating establishments in Kaduna South and Ungwan Rimi industrial areas. Airborne Cr VI concentrations were measured using NIOSH Method 7600. Spirometric lung function tests, fractional exhaled nitric oxide (FeNO) measurement, and respiratory symptom questionnaires were administered. Mean airborne Cr VI concentration was 0.018 mg/m cubed, exceeding the OSHA permissible exposure limit of 0.005 mg/m cubed in 86.1 percent of sampled locations. FeNO elevation indicating airway inflammation was detected in 49.4 percent of exposed workers. Spirometric obstructive patterns were more prevalent in exposed workers (36.1%) compared to controls (8.9%). Years of Cr VI exposure and poor ventilation were the strongest independent predictors of respiratory abnormality. This study provides the first documented Cr VI occupational exposure and respiratory health data from Nigerian electroplating and recommends mandatory Cr VI air monitoring, engineering ventilation controls, pre-employment and periodic spirometric surveillance, and substitution of trivalent chromium alternatives in Kaduna electroplating establishments. Keywords: hexavalent chromium, respiratory health, electroplating, spirometry, Kaduna State.