Levels of soya aeroallergens during dockside unloading as measured by personal and static sampling

Abstract

Soya is an important worldwide agricultural product widely shipped and imported in bulk. It contains a number of recognised allergens and the use of soya products and its dockside unloading have been associated with occupational asthma and community episodes of asthma. Two recognised inhalation soya allergens, soya trypsin inhibitor (STI) and hydrophobic soya protein (HSP), were measured in personal and static air samples collected at a United Kingdom (UK) dock during 3 days of unloading three bulks of processed soya beans and soya pelletised husk. Static samples included task-related and those taken at the workplace perimeter and neighbouring sites. Soluble total protein (STP) and gravimetric dust analyses were also undertaken. While gravimetric dust results in personal air samples were below half of the current UK exposure limit of 10 mg m^-3 for grain dust, and generally less than 0.5 mg m^-3 for the static samples, airborne concentrations for STI and HSP ranged between 0-3,071 and 11-12,629 ng m^-3, respectively, while the correlation between the two specific allergen measurements was generally good (Rank Spearman coefficient 0.74). The data from this investigation suggest that HSP is a more sensitive indicator of soya exposure than STI, but only for soya husk, while STI may be equipotent in detecting exposure to both hull and bean derived soya products. Both assays appear sensitive techniques for investigating the control of exposure to allergenic soy material. The endotoxin level in the husk bulk was 15-60-fold that found in the two chipped bean bulks.