Side-by-side comparison of three sampling methods for aerosolized endotoxin in a wastewater treatment facility

Research studies have established the occurrence of adverse health effects in individuals exposed to organic dusts and water aerosols laden with endotoxin. To determine what exposure levels cause these health effects, it is necessary to quantify airborne endotoxin. Several scientific studies have demonstrated that the quantification of detectable endotoxin is affected by differences in sampling media, analytical method, and aerosol composition. The study reported here performed side-by-side endotoxin sampling using a liquid impinger, a glass fiber filter, and a polycarbonate filter in a wastewater treatment plant. Results show levels of detected endotoxin appear to be highest with the impinger. Coefficients of variation calculated for each sampling method show the glass fiber filter having the least variability when sampling was conducted at the highest endotoxin levels. Lastly, a Spearman rank order correlation test identified an apparent correlation between endotoxin levels obtained with the impinger and the glass fiber filter.