Quantifying Farmers' Exposure to Corn and Soybean Dust in On-Farm Grain Storage Bins

On-farm samples were used to analyze farmers' exposure to dust while cleaning and unloading their grain bins. Over 18% of samples exceeded the 8-hour time-weighted average (TWA) concentration recommended by ACGIH for respirable dust, and over 27% of samples exceeded the ACGIH recommendation for total suspended particles. The results strengthen the need for relevant agricultural safety education programs to help farm workers understand the health hazards associated with grain dust.

Grain dust consists of grain particles, insect parts, silica, bacteria, fungi, and mycotoxins. The size of these airborne particulates is a concern because they can become deeply lodged in the respiratory tract. Exposure to grain dust can diminish overall lung function and lead to respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), organic dust toxic syndrome (ODTS), chronic bronchitis, and hypersensitivity pneumonitis (farmer's lung). Grain storage and handling facilities are primary work locations with high levels of grain dust concentrations. The objective of this study was to understand farmers' exposure to grain dust while cleaning and unloading their grain bins. During on-farm dust sampling, researchers visited farms to collect dust samples for analysis. Two types of samples were taken. Integrated samples provided average concentrations of total dust and respirable dust while farmers performed their normal tasks in the grain bin. Real-time samples provided instantaneous concentrations of respirable dust (RESP) and total suspended particles (TSP) and how the variations changed during the farmers' working periods. From the data collected in corn storage bins, RESP concentrations ranged from 4.1 to 6.6 mg m^-3, and TSP concentrations ranged from 33 to 70.7 mg m^-3. From the data collected in soybean storage bins, RESP concentrations ranged from 1.6 to 82.3 mg m^-3, and TSP concentrations ranged from 8.9 to 146.8 mg m^-3. Based on the calculated 8-hour time-weighted average (TWA) concentration of all samples, 18.2% of the 8-hour TWA RESP concentrations exceeded the ACGIH-recommended respirable dust concentration of 3 mg m^-3, and 27.3% of the 8-hour TWA TSP concentrations exceeded the ACGIH-recommended total dust concentration of 610 mg m^-3. The results strengthen the need for relevant agricultural safety education programs to help farm workers understand the health hazards associated with grain dust.