Work-Related Health Effects among Wastewater Treatment Plants Workers

Background: Raw sewage contains various pathogenic organisms including bacteria, viruses, fungus, worms and protozoa. Workers at wastewater treatment plants (WWTPs) are exposed to these organisms as well as to H2S gas causing many health hazards. Objectives: To assess some work-related health effects among WWTPs workers with special emphasis on the most common infections as well as cardiopulmonary disorders. Methods: 43 workers at Berket Al-Sabih WWTPs were studied. An equal number of non-exposed comparison group were also studied. All participants were asked about their personal demographic data, symptoms suggesting infection, respiratory tract impairment and cardiovascular manifestations. Spirometric measurements were made at the end of the work shift. A resting standard 12-lead ECG was also taken for each participant. For those with a positive ECG finding, echocardiography was also performed. Serum examination for antibodies against hepatitis A virus (HAV) and hepatitis E virus (HEV) was also done. A heparinized blood sample to measure sulf-hemoglobin, as an indicator of H2S exposure, was taken. Stool was analyzed by polymerase chain reaction (PCR) for Leptospira spirochete. Results: WWTPs workers suffered from body ache, abdominal pain, wheeze, asthma and dyspnea more frequently than the comparison group (p<0.05). An obstructive pattern of pulmonary function impairment and a higher mean sulf-hemoglobin% were significantly more common among WWTPs workers than the comparison group. Antibody levels against HAV and HEV as well as frequency of positive stool PCR test results for L. spirochete were significantly higher among WWTPs workers than the comparison group. The prevalence of left ventricular hypertrophy (LVH) according to ECG and mean ejection fraction (EF) as measured by echocardiography were significantly more frequent in WWTPs workers than in the comparison group. Conclusion: WWTPs workers are high risk of developing various infections and cardiopulmonary diseases.