Chromium Exposure and Related Health Effects among Tannery Workers in Kenya

Background. There is increasing concern over the health effects of chromium (Cr) exposure stemming from various activities in tanneries in Kenya. Chromium is a toxic metal in its hexavalent form, and is widely used in the tanning process. Objectives. A detailed exposure assessment of Cr and related health effects among tannery workers in Kenya was performed. Methods. Spot urine and 8-hour full-shift personal breathing zone air samples of the workers (N = 40) and control group (N = 40) were collected and subsequently analyzed for total Cr using atomic absorption spectrophotometry. The medical history, respiratory, and dermatological condition of each of the selected workers was determined. Lung function was further investigated using a spirometer. Results. Tannery workers in various production lines had significantly (P < 0.05) higher mean airborne Cr levels (± standard deviation [SD] of 63.0±11.6 μg/m3) compared to those in the control group (1.39±0.64 μg/m3), and general workers had significantly (P < 0.05) higher mean concentrations of Cr (66.8±13.1 μg/m3) than those in other lines of production. A significant positive association (R2 = 0.76, P < 0.001) was also observed between urinary and breathing zone air Cr levels. Mean urinary Cr level exceeded the American Conference of Governmental Industrial Hygienists biological exposure index for Cr of 30 μg/g creatinine, and 78% of Cr levels of the general workers exceeded this limit. Tannery workers showed a significantly (P < 0.05)higher prevalence of respiratory and dermatological symptoms (30% and 20%, respectively) compared to the control group (10% and 7.5%, respectively). It was further established that production workers had significantly reduced ventilatory function, with 17% experiencing pulmonary obstruction, 13% pulmonary restriction, and 7.5% both manifestations compared to 5% for each of the listed corresponding manifestations in the control group. Conclusions. Our study revealed inadequate engineering controls, work practices and personal hygiene, together with improper management of tannery wastes that has led to considerable exposures to Cr and related health effects among workers. Competing Interests. The authors declare no competing financial interests.