Characterization of exposure to hydrogen sulfide (H2S) among wastewater workers

Every mans shit goes toxic

Handling wastewater carries increased risk of severe health problems and fatal accidents. The main health risk hazard is hydrogensulfide (H2S). Knowledge of how and when exposure to H2S may occur, good work practices, and using safety equipment will reduce therisk and save health and lives. Collecting measurement data from alarm equipped gas sensors provides answers to where the risk is at itspeak, so that risk mitigating action can be conducted with the best effect.

Proper collection, management and adequate treatment of wastewater prior to discharge to the receiving environment is critical for awell functioning modern society, to avoid spreading of 1) Illnesses and diseases, and 2) Pollutants. This means that as a society, we areobliged to give employees the necessary protection against exposure to hazardous substances and gases that are found in wastewater.Society cannot expect workers to risk their lives in providing the critical environmental municipal services that we have come to expectand depend on. Deaths are fortunately rare. However, we see that lung capacity among Norwegian wastewater collection and treatmentemployees are lower than expected (K. E. Heldal et al., 2016; Kari Kulvik Heldal et al., 1991).

There are significant variations between municipalities in technical standards of wastewater treatment and handling facilities, and in theknowledge related to wastewater work associated risks. Unfortunately, gas sensors with warning alarms are not in use everywhere. Thiswork will develop knowledge and help colleagues and municipalities in all of Norway, and hopefully beyond, to make good choices forrisk reduction and control in facility design, in choice of alarm- and security equipment and in information and education of thewastewater workers.

Handling wastewater gives increased risk of severe health problems and fatal accidents. Knowing the exposure pattern, good workpractice and use of safety equipment will reduce risk and save health and lives. Collecting measurement data from alarm sensors givesanswers to where the risk is at its peak, so that risk mitigating action can be conducted where they will have the best effect.

Hydrogen sulfide from sewage handling is a challenge to municipal authorities and wastewater workers. The risks related to highexposure to hydrogen sulfide is well documented.

Hydrogen sulfide is formed during degradation of biological material under lack of oxygen. The gas is partly trapped in the sedimentsand partly released from the sewage. As gas bubbles bursts from the sediments, the gas enters work space. This happens bothcoincidentally and as a result of active work in the facilities.

An exposure index of H2S was created from data in Stami project "Exposure and health effects on the airways an central nervous syatem by handling of wastewater" 2013-2017 (https://stami.no/ny-stami-rapport-eksponering-og-helseeffekter-pa-luftveiene-og-sentralnervesystemet-ved-handtering-av-avlopsvann/). The further study aims to give a methodology that in a simple way calculatesthe index values from large series of measurements (part 2), so we can provide a full/ broad exposure profile to show the width of theexposure and give better understanding of exposure and risk. To get the broad exposure profile, we want to collect all data for selectedweeks, in three periods of 14 days (10 working days), from as many as possible of the workers. During these periods they must dock inevery day, and register the activity (task), place, time, duration and comments. This will allow pairing of exposure and task in a form oflog book procedure. The exposure profiles can then be put together, due to information of tasks, duration and places. This will hopefullyease the risk evaluation and choice of precautive measures.We expect that in particular smaller municipalities without a safety department will benefit from the new data, but we expect it to beimportant for all actors involved with wastewater work in Norway, and hopefully elsewhere.