Cognitive functions changes among Egyptian sewage network workers

Farahat, Sahar Ali; Kishk, Nirmeen A.

doi:10.1177/0748233710364966

Cited by 19 publications

(13 citation statements)

References 30 publications

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“…Most other H 2 S studies with cognitive function tests have involved occupationally or industrially exposed populations (De Fruyt et al, 1998, Farahat and Kishk, 2010, Kilburn, 1997) where H 2 S exposure can be difficult to quantify. Some used duration of H 2 S exposure, rather than H 2 S measurements (Kilburn, 1997, 2003), while others reported few measurements (Kilburn et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

Chronic ambient hydrogen sulfide exposure and cognitive function

Reed

Crane

Garrett

et al. 2014

Neurotoxicology and Teratology

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Background Exposures to hydrogen sulfide gas (H2S) have been inconclusively linked to a variety of negative cognitive outcomes. We investigated possible effects on cognitive function in an urban population with chronic, low-level exposure to H2S. Methods Participants were 1,637 adults, aged 18-65 years from Rotorua city, New Zealand, exposed to ambient H2S from geothermal sources. Exposures at homes and workplaces were estimated from data collected by summer and winter H2S monitoring networks across Rotorua in 2010/11. Metrics for H2S exposure at the time of participation and for exposure over the last 30 years were calculated. H2S exposure was modeled both as continuous variables and as quartiles of exposure covering the range of 0 – 64 ppb (0-88 μg/m3). Outcomes were neuropsychological tests measuring visual and verbal episodic memory, attention, fine motor skills, psychomotor speed and mood. Associations between cognition and measures of H2S exposure were investigated with multiple regression, while covarying demographics and factors known to be associated with cognitive performance. Results The consistent finding was of no association between H2S exposure and cognition. Quartiles of H2S exposure had a small association with simple reaction time: higher exposures were associated with faster response times. Similarly, for digit symbol, higher H2S exposures tended to be marginally associated with better performance. Conclusion The results provide evidence that chronic H2S exposure, at the ambient levels found in and around Rotorua, is not associated with impairment of cognitive function.

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Section: Discussionmentioning

confidence: 99%

Chronic ambient hydrogen sulfide exposure and cognitive function

Reed

Crane

Garrett

et al. 2014

Neurotoxicology and Teratology

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“…Several studies have shown that the range of symptoms are also broad, extending from central nervous system (CNS), respiratory, and gastrointestinal symptoms to infection and flu-like symptoms (Lundholm and Rylander, 1983, Melbostad et al, 1994, Douwes et al, 2001, Thorn et al, 2002, Heldal et al, 2010. Of all the airborne exposure associated with handling waste water at sewage treatment plants, hydrogen sulphide (H2S) from degradation of organic material in the sewage and endotoxins from Gram-negative bacteria are of particular interest (Adelson and Sunchine, 1966, Beauchamp et al, 1984, Latinen et al, 1994, Farahat and Kishk, 2010. High-dose acute exposure to H2S can be extremely hazardous, being able to cause pulmonary oedema (> 300 ppm) and sudden unconsciousness (> 500 ppm) or death by even a single exposure at levels above 1,000 ppm (NEG 2001).…”

Section: Introductionmentioning

confidence: 99%

“…High-dose acute exposure to H2S can be extremely hazardous, being able to cause pulmonary oedema (> 300 ppm) and sudden unconsciousness (> 500 ppm) or death by even a single exposure at levels above 1,000 ppm (NEG 2001). However, repeated exposure to low levels of H2S (1-10 ppm) may possibly result in chronic symptoms from the CNS, such as fatigue, headache, poor memory and concentration difficulties (Tvedt et al, 1991, Richardson, 1995, Watt et al, 1997, Lee et al, 2007, Farahat and Kishk, 2010.…”

Section: Introductionmentioning

confidence: 99%

Endotoxin and Hydrogen Sulphide Exposure and Effects on the Airways Among Waste Water Workers in Sewage Treatment Plants and Sewer Net System

Heldal

Austigard

Svendsen

et al. 2019

Annals of Work Exposures and Health

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Background: The purpose of this study is to investigate whether airborne exposure to endotoxins, hydrogen sulphide (H2S) and inhalable particles negatively impacts the respiratory system and inflammatory blood proteins in sewage plant and sewer net system workers, and further to determine dose-response associations between exposure and health outcomes.Methods: In total, 148 waste water workers (WWWs) from urban and rural sewage plants and the sewer net system participated. One hundred and twenty-one workers were exposed to sewage, 46 from sewage plants and 75 from the sewer net system.Twenty-seven workers were characterized as little or not exposed and served as an internal reference group. Personal inhalable samples were analysed for endotoxins (Limulus assay), particle dust (gravimetrically) and Salmonella and Yersinia spp. (polymerase chain reaction method, PCR). Levels of H2S were measured using personal electro chemical sensors. Intercellular adhesion molecule 1(ICAM-1), interleukin 8 (IL-8), surfactant protein D (SP-D), club cell protein 16 (CC16) and macrophage inflammatory protein (MIP) were determined by enzyme-linked immunosorbent assay and C-reactive protein (CRP) by an HS-MicroCRP assay in blood samples.Results: Workers in sewage plants were exposed to significantly higher levels of endotoxins compared to workers in the sewer net system (median 55 EU/m 3 (4-262 EU/m 3 ) and median 27 EU/m 3 (1-304 EU/m 3 ), respectively). The estimated H2S index showed higher values when working in the sewer net system (median 3.1 (0.5-78.1) compared to workers at the sewage plants (median 1.3 (0.5-9.3), and the most excessive exposure was collecting sewage from cesspools (273 ppm). No viable airborne Salmonella and Yersinia spp. were detected. The exposed workers had significantly higher CRP compared to the referents (1.2 µg/ml (0.1-19.0 µg/ml) and 0.8 µg/ml (0.1-5.0 µg/ml), respectively) and lower forced expiratory volume in 1 s (FEV1 %) (92.6 %, SD 14.6) and 102.0 %, SD10.1, respectively), with numbers given as mean and standard deviation. The serum concentration of CRP was significantly and negatively associated with FEV1% (β = -7.7, R 2 = 0.05) and FVC% (β = -8.5, R 2 = 0.08), and the serum concentration of ICAM-1 with the estimated exposure to H2S (β = -19.9, R 2 = 0.07). Conclusion:Despite moderate levels of endotoxin and H2S exposure, the results indicate an impact of these agents on lung function and the adhesion molecule ICAM-1, and a low-grade systemic inflammation was indicated in increased levels of CRP.

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“…WWWs commonly suffer from various health symptoms, including neurological and respiratory tract [ 1 – 5 ]. These effects have been ascribed to exposure to microorganisms and noxious gases such as H 2 S or from exposure to low levels of different biological and chemical agents [ 1 , 4 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

“…In particular H 2 S exposure has been associated with cognitive impairment among WWWs [ 5 ] and neurological symptoms [ 2 , 7 ].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen sulphide exposure in waste water treatment

Austigard

Svendsen

Heldal

2018

J Occup Med Toxicol

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BackgroundThe aims of this study was to assess exposure to hydrogen sulphide (H2S) among waste water treatment workers (WWWs), and achieve a better measure of the risks of H2S exposure than only using the eight-hour average value and the ceiling value because the exposure pattern of H2S for WWWs is dominated by short-term peaks.MethodsNinety-three measurements of H2S from 56 WWWs in three cities and three rural areas were collected. All exposure measurements were carried out from the start of the day until lunch time (sampling time 4–5 h) when most of the practical work was performed. The type of tasks and extent of flushing were registered. H2S was measured using direct-reading instruments with logging: OdaLog L2/LL, Dräger X-am 5000 and Dräger Pac 7000 (0.1–200 ppm). Number and duration of peaks for different work tasks, seasons, places and extent of flushing were combined in an exposure index (IN), and evaluated in a mixed-model analysis, building a model aimed to predict exposure for different job tasks.ResultsNine Percent (8 of 93) of all H2S measurements have peaks above 10 ppm; in addition, 15% (14 of 93) have peaks of 5–10 ppm, 35% (33 of 93) have peaks of 1–5 ppm and 65% (62 of 93) have peaks of 0.1–1 ppm. 29% of the measurements of hydrogen sulphide showed no registered level > 0.1 ppm.From the mixed-model analyses we see that exposure level, expressed as H2S index IN, varied between places, work type, season and degree of flushing. For the work in a plant in the capital, the exposure index varied from 0.02 for working in spring doing some flushing, to 0.7 for working at the same plant in winter doing flushing more than three times or more than 10 min. Collecting sewage from cesspools in city 2 in winter doing a lot of flushing gave a hydrogen sulphide index of 230.ConclusionsThe use of a H2S index, taking into consideration peak height, duration and number of peaks, could be a tool for exposure assessment for H2S.

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Cognitive functions changes among Egyptian sewage network workers

Cited by 19 publications

References 30 publications

Chronic ambient hydrogen sulfide exposure and cognitive function

Chronic ambient hydrogen sulfide exposure and cognitive function

Endotoxin and Hydrogen Sulphide Exposure and Effects on the Airways Among Waste Water Workers in Sewage Treatment Plants and Sewer Net System

Hydrogen sulphide exposure in waste water treatment

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