Impact of Industrial Pollution on Human Renal Function and Male Reproductive Hormones: An Investigation of Heavy Metals Toxicity and Oxidative Stress

Industrial pollution provides significant public health risks through exposure to heavy metals (HMs). This study assessed serum HMs (Cd, Cr, Ni, Sn, Zn, and B), oxidative stress (OS) markers, renal function biomarkers, and male reproductive hormones in 135 participants across rural, urban, and industrial areas (Erbil Province, Iraq), using ICP-MS, ELISA, and automated immunoassays. Industrial workers showed significantly elevated HMs concentration, particularly for Cd [industrial: 0.203 (0.37), 95% CI: 0.136-0.288 vs. rural: 0.102 (0.07) μg/L, 95% CI: 0.085-0.102; d = 1.2445, p = 0.007]. Conversely, Zn concentration was significantly reduced in urban [2162 (1944) vs. 3991 (1110) μg/L in rural; d = 1.029, p = 0.0029]. OS markers (NO, CAT, and GPx) were significantly diminished in the urban/industrial areas (p < 0.0001). Whereas, 8-OHdG showed no significant differences (p > 0.05). Renal function biomarkers indicated that residents and workers in urban/industrial areas had urea increased by 26%-27%, with creatinine elevated by 16%-19% compared to the rural residents. Moreover, industrial workers had significantly higher levels of FSH, LH, and testosterone by 38.9%, 42.9%, and 24.9%, respectively, compared to the rural residents. Zn had positive associations with GPx (r = 0.6199, p < 0.0001) and CAT (r = 0.4800, p < 0.0001). Similarly, there were positive associations of Cd with creatinine (r = 0.3586, p = 0.0015) and testosterone (r = 0.3050, p = 0.0063), while it was negatively associated with CAT (r = -0.3344, p = 0.005). These findings demonstrate that HMs exposure in the industrial area causes systematic toxicity, particularly with Cd leading to renal and endocrine dysfunction by increasing OS markers. The identified exposure response associations underscore the necessity for intensive environmental monitoring and occupational safety intervention in the high-risk industrial areas.