Risk assessment of toxic hydrogen sulfide concentrations on swine farms

Hydrogen sulfide is a highly toxic gas, causing many lethal accidents in farming environment. Until now, the understanding of the interactive impact of different variables on hydrogen sulfide concentrations on swine farms has been limited. The risk of high hydrogen sulfide concentrations has not yet been assessed comprehensively. The main goal of this study is to identify and investigate the variables, which significantly influence hydrogen sulfide concentrations, and to assess the risk of exposure to toxic hydrogen sulfide concentrations on swine farms. A generalized linear model was built to show the intertwining impact of different variables, and, on the basis of this model, sensitivity analysis, stress tests and Monte Carlo simulations were conducted to thoroughly assess the risk of exposure to dangerous hydrogen sulfide concentrations. Use of generalized linear models and risk assessment tools is a novelty in this context. The model results show that the most significant variables are the location of sample origin, manure disturbance, pig age, weight and diet. If hydrogen sulfide is measured outside a barn, the concentration is up to 47-times lower than inside a barn. Hydrogen sulfide concentration increases by a factor of 7 if manure is pumped during the observation period. Operations with growing pigs have the highest expected hydrogen sulfide concentrations in comparison to other pig age groups. Risk assessment analysis additionally reveals that certain combinations of variable values result in lethal hydrogen sulfide concentrations, and that the likelihood of such scenarios can reach 0.69%.

Automated summary

This study aims to comprehensively assess the risk of exposure to toxic hydrogen sulfide concentrations on swine farms through the use of a generalized linear model and risk assessment tools. It identifies key variables influencing hydrogen sulfide concentrations and reveals that certain combinations of variable values may result in lethal hydrogen sulfide concentrations.