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

Handling wastewater gives increased risk of severe health problems and fatal accidents. Knowing the exposure pattern, good work practice and use of safety equipment will reduce risk and save health and lives. Collecting measurement data from alarm sensors gives answers 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 high exposure 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 sediments and partly released from the sewage. As gas bubbles bursts from the sediments, the gas enters work space. This happens both coincidentally and as a result of active work in the facilities. An exposure index of H2S was created in part 1 of the study. The further study aims to give a methodology that in a simple way calculates the index values from large series of measurements (part 2), so we can provide a full/ broad exposure profile to show the width of the exposure and give better understanding of exposure and risk. To get the broad exposure profile, we want to collect all data for selected weeks, in three periods of 14 days (10 working days), from as many as possible of the workers. During these periods they must dock in every day, and register the activity (task), place, time, duration and comments. This will allow pairing of exposure and task in a form of log book procedure. The exposure profiles can then be put together, due to information of tasks, duration and places. This will hopefully ease 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 be important for all actors involved with wastewater work in Norway, and hopefully elsewhere. An article covering calculation of index value of H2S from large dataset was published in june 2021.

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Handling wastewater gives increased risk of severe health problems and fatal accidents. Knowing the exposure pattern, good work practice and use of safety equipment will reduce risk and save health and lives. Collecting measurement data from alarm sensors gives answers 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 high exposure 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 sediments and partly released from the sewage. As gas bubbles bursts from the sediments, the gas enters work space. This happens both coincidentally and as a result of active work in the facilities. An exposure index of H2S was created in part 1 of the study. The further study aims to give a methodology that in a simple way calculates the index values from large series of measurements (part 2), so we can provide a full/ broad exposure profile to show the width of the exposure and give better understanding of exposure and risk. To get the broad exposure profile, we want to collect all data for selected weeks, in three periods of 14 days (10 working days), from as many as possible of the workers. During these periods they must dock in every day, and register the activity (task), place, time, duration and comments. This will allow pairing of exposure and task in a form of log book procedure. The exposure profiles can then be put together, due to information of tasks, duration and places. This will hopefully ease 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 be important for all actors involved with wastewater work in Norway, and hopefully elsewhere.