ABSTRACT

Hydrogen Sulfide (H2S) is produced in manure storage facilities and released during manure agitation. Exposure to this gas presents health risks to workers at daily exposure of greater than 10 parts per million (ppm). Exposure levels on BC dairy farms are unknown. The aim of this study was to document peak H2S exposure levels to operators and bystanders during manure agitation on British Columbia dairy farms to determine if action levels were exceeded. Farms were evaluated at two time points during manure agitation. Both operator exposure and potential exposure sampling were undertaken. Peak hydrogen sulfide levels were measured and categorized as greater than or less than the ceiling level (10 ppm) and action level (5 ppm). Associations between H2S levels above the ceiling level and farm factors were assessed. Measures were recorded at 43 dairy farms with 91 total measures recorded. Action levels were exceeded in 30% of operator measures and 64% of potential exposure measures while 20% of operator and 53% of potential peak H2S measures exceeded 10 ppm. Manure storage facilities were evenly distributed between indoor and outdoor locations with under-barn (43%) and outdoor storage (47%) most common. Sawdust was the most prominent bedding type (65%). Tractor operated propeller was the most common type of agitation equipment (62%). Manure temperature remained a significant predictor in the multivariate model for operator peak exposure. Exposure to H2S above the action level commonly occurs on BC Dairy farms. Given that Worksafe BC requires exposure control plans for H2S levels above 5 ppm, and that on dairy farms, measures of operator and potential H2S exposures were recorded above these levels, best practices to reduce potential H2S exposure are necessary to reduce possible operator and bystander exposure.

摘要

硫化氢 (H2S) 在粪便储存设施中产生，并在粪便搅拌过程中释放。每天暴露在这种气体中的工人的健康风险超过百万分之 10 (ppm)。BC 奶牛场的暴露水平未知。本研究的目的是记录不列颠哥伦比亚省奶牛场粪便搅拌期间操作员和旁观者的 H2S 暴露峰值水平，以确定是否超出了行动水平。在粪便搅拌期间的两个时间点对农场进行评估。进行了操作员暴露和潜在暴露采样。测量硫化氢峰值水平并将其归类为高于或低于上限水平 (10 ppm) 和行动水平 (5 ppm)。评估了高于上限水平的 H2S 水平与农场因素之间的关联。在 43 个奶牛场记录了措施，总共记录了 91 项措施。30% 的操作员措施和 64% 的潜在接触措施超过了行动水平，而 20% 的操作员和 53% 的潜在峰值 H2S 措施超过了 10 ppm。粪便储存设施均匀分布在室内和室外位置，最常见的是谷仓下 (43%) 和室外储存 (47%)。锯末是最突出的垫料类型 (65%)。拖拉机操作的螺旋桨是最常见的搅拌设备类型 (62%)。粪便温度仍然是操作员峰值暴露的多变量模型中的重要预测因子。BC 奶牛场通常会接触到高于行动水平的 H2S。鉴于 Worksafe BC 需要针对高于 5 ppm 的 H2S 水平以及奶牛场的暴露控制计划，