Lead Exposure and Blood Pressure among Workers in Diverse Industrial Plants in Kenya

Abstract

The study evaluated airborne exposures and blood lead (BPb) levels in 233 production workers at six diverse industrial plants in Kenya. Blood and personal breathing zone air samples were collected and analyzed for lead (Pb) using atomic absorption spectroscopy. Blood pressure (BP) levels were measured using a standard mercury sphygmomanometer. The results indicated mean airborne Pb levels ± standard deviation (SD) as follows: 183.2 ± 53.6 μg/m³ in battery recycling, 133.5 ± 39.6 μg/m³ in battery manufacturing, 126.2 ± 39.9 μg/m³ in scrap metal welding, 76.3 ± 33.2 μg/m³ in paint manufacturing, 27.3 ± 12.1 μg/m³ in a leather manufacturing, and 5.5 ± 3.6 μg/m³ in a pharmaceutical plant. The mean airborne Pb levels exceeded the U.S. Occupational Safety and Health Administration (OSHA) 8-hr time-weighted average (TWA) permissible exposure limit (PEL) for Pb of 50 μg/m³ in the battery manufacturing, battery recycling, welding, and paint manufacturing plants. Similarly, mean BPb concentrations exceeded the American Conference of Governmental Industrial Hygienists (ACGIH®) biological exposure index (BEI) for Pb of 30 μg/dl. A significant positive association was observed between BPb and breathing zone air Pb (R² = 0.73, P < 0.001). Approximately 30% of the production workers (N = 233) were in the hypertensive range with an average systolic and diastolic blood pressure (BP) of 134.7 ± 12.7 mmHg and 86.4 ± 8.9 mmHg, respectively. In the multivariate regression analysis, age, duration of work, airborne Pb and BPb levels were significantly associated (P < 0.05) with a change in BP. We recommend improved engineering controls, work practices, and personal hygiene to reduce Pb exposures. In addition, workers should undergo comprehensive medical surveillance to include BPb and BP testing, and airborne Pb assessments in all industries with significant lead exposures.

Keywords:

• blood lead
• airborne lead
• occupational exposure
•  blood pressure
• industrial workers

ACKNOWLEDGMENTS

The authors thank the National Commission for Science, Technology and Innovation (NACOSTI) for their financial support (NCST/5/003/018) and approvals (NCST/5/002/R/346) for research, and also the Ministry of Medical Services, Office of the Director Medical Services, Nairobi, for issuing the relevant permits. The authors acknowledge the Directorate of Occupational Safety and Health Services (DOSHS), the Mines and Geological Department, the University of Nairobi, and the Kenya Industrial Research and Development Institute (KIRDI) for providing technical support and research facilities, and Ravi Sharma of the Aga Khan University Hospital for technical support, and the employee participants and managers of the surveyed plants. The authors also acknowledge Stephen Rothenberg for reviewing the draft manuscript.