title: Monitoring risks in association with exposure levels among wastewater treatment plant workers.
abstract: OBJECTIVE
  To investigate the relationship between exposure to hydrogen sulfide and endotoxin during specific job tasks and health symptoms among wastewater treatment plant (WWTP) workers.
  
  
  METHODS
  The exposure levels for specific tasks were measured by personal monitoring. The health symptoms of WWTP workers were compared with those of water treatment plant workers through a questionnaire survey.
  
  
  RESULTS
  Exposure levels for all monitored tasks were less than 1 ppm for hydrogen sulfide and 91 EU/m (endotoxin units/m) for endotoxin. Statistically higher odds ratios of respiratory, ocular and skin irritation, neurology, and gastrointestine symptoms were shown among WWTP workers compared with water treatment plant workers. Tasks related to sludge handling and plant inspection showed statistically significant associations with memory/concentration difficulties, throat irritation, and stomach pain.
  
  
  CONCLUSIONS
  These results suggest that exposure control programs for specific job tasks and work locations are needed.
authors.affiliation: Health Protection Office, The University of Iowa, Iowa City, IA 52246, USA. eunice-lee@uiowa.edu
authors.forename: Joung Ae
authors.initials: JA
authors.lastname: Lee
authors.forename: Peter S
authors.initials: PS
authors.lastname: Thorne
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Reynolds
authors.forename: Patrick T
authors.initials: PT
authors.lastname: O'Shaughnessy
mesh_terms: D000395:Air Pollutants, Occupational / Q000009:adverse effects* / Q000032:analysis; D004731:Endotoxins / Q000009:adverse effects* / Q000032:analysis; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005767:Gastrointestinal Diseases / Q000453:epidemiology; D006801:Humans; D006862:Hydrogen Sulfide / Q000009:adverse effects* / Q000032:analysis; D019570:Inhalation Exposure; D009422:Nervous System Diseases / Q000453:epidemiology; D009784:Occupational Diseases / Q000453:epidemiology* / Q000209:etiology; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis; D015995:Prevalence; D012140:Respiratory Tract Diseases / Q000453:epidemiology; D018570:Risk Assessment; D012498:Sanitary Engineering; D012871:Skin Diseases / Q000453:epidemiology; D011795:Surveys and Questionnaires; D014865:Waste Disposal, Fluid
chemical_list: D000395:Air Pollutants, Occupational; D004731:Endotoxins; D006862:Hydrogen Sulfide