Sickness among waste water plant personnel

        The peer-reviewed medical literature from developed countries contains many studies demonstrating that, relative to control groups, workers in waste water treatment plants, composting facilities, and sludge treatment facilities commonly have reduced lung function (adult bronchial asthma, acute bronchoconstriction levels, elevated mucous membrane irritation levels), skin disorders, diarrhea, urinary mutagens and other gastrointestinal symptoms. They typically suffer symptoms such as tiredness, headache, cough, sputum production, wheezing, sore throat and eye and skin complaints more often than do control groups. Exposure to bioaerosols and endotoxins associated with organic dusts are implicated in several studies. Antibodies to various diseases (influenza, parainfluenza, herpes, coronavirus, rickettsia) are present at higher frequency than is true of control groups in at least one study. Some studies found increased risk of occupationally acquired hepatitis A, B and C, whereas other studies did not. A higher incidence of cancer in workers exposed to sewage sludge has not been documented.
        Workers, mostly men in their prime working years, are demonstrably adversely affected by contact with sewage sludge. By extension, the general population (especially children, the elderly, those with respiratory problems and compromised immune systems) would likely be more susceptible to diseases from dust and direct contact with land-applied sewage sludge. The National Institute of Occupational Safety and Health (NIOSH) released revised recommendations to protect workers exposed to Class B sludge ( which contains additional references.


Arvanitidou M, Constantinidis TC, Doutsos J, Mandraveli K and Katsouyannopoulos V (1998) Occupational hepatitis B virus infection in sewage workers. Med Lav 89: 437-444.
“However, the logistic regression analysis confirmed that only exposure to sewage was independently associated with positivity for HBV infection (p < 0.001).

Babish JG, Stoewsand GS, Kranz JM, Boyd JN, Ahrens VD and Lisk DJ (1984) Toxicologic studies associated with the agricultural use of municipal sewage sludge and health effects among sewage treatment plant workers. Regul Toxicol Pharmacol 4(3): 305-321.
“Epidemiologic evidence of possible adverse health effects among sewage plant workers exposed to aerosolized pathogens or synthetic organic vapors during wastewater treatment or land spreading of sludge is still inconclusive.” “Other possible deleterious environmental effects include pollution of groundwater and toxicity to birds consuming worms or insects inhabiting sludge-treated soils.”

Brautbar N and Navizadeh N (1999) Sewer workers: Occupational risk for hepatitis C--report of two cases and review of literature. Arch Environ Health 54: 328-330.
“…sewer workers may be at increased risk of contracting hepatitis C.”

Brugha R, Heptonstall J, Farrington P, Andren S, Perry K and Parry J (1998) Risk of hepatitis A infection in sewage workers. Occup Environ Med 55: 567-569.
“Of 50 employees who reported occupational exposure to raw sewage most of the time, 30 (60%) had had HAV infection.”

Darragh A and Sandfort D (1996) Quantification of air contaminants at a municipal sewage sludge composting facility in Colorado. 1996-03-05 Occupational Health and Safety Section, Colorado State University, Fort Collins, CO 80523.
“According to the International Committee on Occupational Health, 21 percent of the collected endotoxin concentrations exceeded levels which may cause organic dust toxic syndrome (ODTS), 69 percent exceeded acute bronchoconstriction levels, and 100 percent exceeded the mucous membrane irritation level.”

De Serres G and Laliberte D (1997) Hepatitis A among workers from a waste water treatment plant during a small community outbreak. Occup Environ Med 54(1): 60-22.

“This report confirms that hepatitis A is an occupational hazard for sewage workers.”

Douwes J, Mannetje A and Heederik D (2001) Work-related symptoms in sewage treatment workers. Ann Agric Environ Med 8(1): 39-45.
“In conclusion, sewage treatment workers develop a large variety of work-related symptoms that are not likely caused by endotoxin exposure only.”

Dutkiewicz J, Jablonski L and Olenchock SA (1988) Occupational biohazards: a review. Am J Ind Med 14(5): 605-623.
“There is growing evidence that biohazards are also important risk factors for many other professions, including woodworkers, workers of textile plants, sewage and compost workers, miners and renovators.”

Friis L, Norback D and Deling C, (1999) Self-Reported Asthma and Respiratory Symptoms in Sewage Workers. J. Occup. Health 41: 87-90.
“Self-reported asthma was more common among the sewage workers than other municipal workers.”

Friis L (2001) Health of municipal sewage workers. Comprehensive Summaries of Upsala Dissertations from the Faculty of Medicine 1015, 67p. (
“In a cohort of municipal sewage workers there was no increase in the overall incidence of cancer when compared to the general population” “Sewage workers reported adult bronchial asthma significantly more than the referents.”

Glas C, Hotz P and Steffen R (2001) Hepatitis A in workers exposed to sewage: a systematic review. Occup Environ Med 58(12): 762-768.
“The systematic review does not confirm an increased risk of clinical HA in workers exposed to sewage.”

Gregersen P, Grunnet K, Uldum SA, Andersen BH and Madsen H (1999) Pontiac fever at a sewage treatment plant in the food industry. Scand J Work Environ Health 25: 291-295.
“It was concluded that the fever was caused by L. pneumophila emitted to the environment by the uncovered (sewage) decanter.”

Iftimovici R, Iacobescu V, Copelovici Y, Dinca A, Iordan L, Niculescu R, Teleguta L and Chelaru M (1980) Prevalence of antiviral antibodies in workers handling wastewater and sludge. Virologie 31(3): 187-189.
“The sera were tested against influenza, parainfluenza, adeno-, herpes, coronavirus, rickettsial and chlamydial antigens, as well as for the presence of HBsAg and anti-HBs. Statistically significant differences between group A (direct contact) and groups B (occupational contact) and C (control) were found as regards the prevalence of antibodies to adenovirus and parainfluenza virus type 1 antigens.”

Kraut A, Lilis R, Marcus M, Valciukas JA, Wolff MS and Landrigan PJ (1988) Neurotoxic effects of solvent exposure on sewage treatment workers. Arch Environ Health 43(4): 263-268.

“Nineteen Sewage Treatment Workers (STWs) exposed to industrial sewage that contained benzene, toluene, and other organic solvents at a primary sewage treatment plant in New York City were examined for evidence of solvent toxicity. Fourteen (74%) complained of central nervous system (CNS) symptoms consistent with solvent exposure, including lightheadedness, fatigue, increased sleep requirement, and headache. The majority of these symptoms resolved with transfer from the plant.”

Laitinen S, Kangas J, Kotimaa M, Liesivuori J, Martikainen PJ, Nevalainen A, Sarantila R and Husman K (1994) Workers' exposure to airborne bacteria and endotoxins at industrial wastewater treatment plants. Am Ind Hyg Assoc J 55(11): 1055-1060.
“The microbiological contamination of air was highest near the inlets where incoming wastewater entered the basins, in the sludge treatment area, and inside the biofilter tower.”

Lundholm M and Rylander R (1980) Work related symptoms among sewage workers. Br J Ind Me 40(3): 325-329.
“A significantly higher proportion of employees at sewage treatment plants reported skin disorders, diarrhoea, and other gastrointestinal symptoms than the control group.”

Lundholm M and Rylander R (1980) Occupational symptoms among compost workers. J Occup Med 22(4): 256-257.
“Exposure to gram-negative bacteria and the presence of subjective symptoms among workers were investigated at an experimental compost plant. Four of the 11 workers reported nausea, headache, and diarrhea, an incidence greater than that reported by workers in a drinking water plant. The number of airborne gram-negative bacteria was high where household garbage was agitated by the technical equipment. The findings are similar to those in studies on workers in sewage treatment plants.”

Mattsby I and Rylander R. (1978) Clinical and immunological findings in workers exposed to sewage dust. J Occup Med 20(10): 690-692.
“A clinical investigation was made between workers exposed to dried sewage sludge dust and age matched controls not exposed. About 50% of the workers reported work related fever, eye symptoms and general fatigue. Thirteen percent of the workers in the sewage plant reported work-related diarrhea. Serum immunoglobulins, white blood cells and thrombocytes were elevated and a higher percentage of increased levels of C-reactive protein and fibrinogen degradation products was found in the exposed group. Although no definite cause-effect relationship could be established, it is suggested that the responsible agent in the environment is endotoxins.”

Melbostad E, Eduard W, Skogstad A, Sandven P, Lassen J, Sostrand P and Heldal K (1994) Exposure to bacterial aerosols and work-related symptoms in sewage workers. Am J Ind Med 25(1): 59-63.
“An association between levels of total bacteria, rod-shaped bacteria, and symptoms, such as tiredness and headache, during and after work was found.”

Morse DL, Kominsky JR, Wisseman CL 3d and Landrigan PJ (1979) Occupational exposure to hexachlorocyclopentadiene. How safe is sewage? JAMA 241: 2177-2179.
“This episode demonstrates the toxicity of HCCPD and emphasizes the vulnerability of sewage workers to chemical toxins in wastewater systems.”

Nethercott JR and Holness DL (1988) Health status of a group of sewage treatment workers in Toronto, Canada. Am Ind Hyg Assoc J 49(7): 346-350.
“This investigation revealed that many workers reported "influenza-like" symptoms, cough, sputum production, wheezing, sore throat and skin complaints. The workers tended to have somewhat reduced lung function.”

NIOSH HETA 94-0182-2519. Waste Water treatment Health Hazard Evaluation, Little Blue Valley Sewer District, Independence MO.
“Respiratory protection is recommended …… until work practices and engineering controls can effectively reduce H2S exposures below recommended levels.

NIOSH HETA 83-440-1537. Occupational Fatality Following Exposure to Hydrogen Sulfide - Nebraska.
“The exact circumstances resulting in the worker's death may never be known. NIOSH investigators concluded that the factors contributing to the death included: (1) the summer temperature and the long transit time of the sewage entering the plant (resulting in high concentrations of dissolved H2S); (2) inappropriate design of the ventilation system; and (3) inadequate safety procedures for workers entering potentially dangerous areas.”

Richardson DB (1995) Respiratory effects of chronic hydrogen sulfide exposure. Am J Ind Med 28(1): 99-108.
“In conclusion, this study found evidence that chronic low level exposure to H2S may be associated with reduced lung function.”

Rylander R (1999) Health effects among workers in sewage treatment plants. Occup Environ Med 56(5): 354-357.
“The results confirm previous studies on the presence of airways and intestinal inflammation among workers in sewage treatment plants.”

Salano R and Copello F (1998) An epidemiological study of a group of workers employed in the maintenance of a sewer network and of urban waste water treatment plants. Med Lav 89: 393-403.
“The relative risk of alterations in respiratory function (both instrumental and clinical findings) was increased among the waste water treatment workers. The average platelets count in the exposed workers appeared to be significantly reduced compared to non-exposed subjects although both were within the normal limits.”

Scarlett-Kranz JM, Babish JG, Strickland D and Lisk DJ (1987) Health among municipal sewage and water treatment workers. Toxicol Ind Health 3(3): 311-319.
“Sewage workers reported a significantly higher frequency of headache, dizziness, sore throat, skin irritation and diarrhea within the month immediately preceding receipt of the questionnaire, after controlling for various possible confounders. Eye and skin irritation were significantly associated with exposure to mutagens.”

Scarlett-Kranz JM, Babish JG, Strickland D, Goodrich RM and Lisk DJ (1986) Urinary mutagens in municipal sewage workers and water treatment workers. Am J Epidemiol 124(6): 884-893.
“Sewage workers had a significantly higher risk for urinary mutagens.”

Schlosser O, Grall D and Laurenceau MN (1999) Intestinal parasite carriage in workers exposed to sewage. Eur J Epidemiol. 15: 261-265.
“The results of this study emphasize an occupational risk of intestinal protozoan infestation in workers exposed to sewage.”

Weldon M, VanEgdom MJ, Hendricks KA, Regner G, Bell BP and Sehulster LM (2000) Prevalence of antibody to hepatitis A virus in drinking water workers and wastewater workers in Texas from 1996 to 1997. J Occup Environ Med 42(8): 821-826.
“Wastewater workers in this study had a higher prevalence of anti-HAV than drinking water workers, which suggested that wastewater workers may have been at increased risk of occupationally acquired hepatitis A.”

Zuskin E, Mustajbegovic J and Schachter EN (1993) Respiratory function in sewage workers. Am J Ind Med 23(5): 751-761.
“Our data indicate that sewage workers experience frequent acute and chronic respiratory symptoms and exhibit objective evidence of respiratory dysfunction.”

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