Biomonitoring of indoor particle contamination by detection of bioluminescence reduction of marine bacterium Vibrio fischeri

Bioassay, which detects biohazardous property of environmental contaminants, is still being an unexplored field of air quality monitoring. This study aims to develop a simple testing system of toxicity of the indoor particulate matter by detecting bioluminescence reduction of marine bacterium Vibrio fischeri. Suspended particulate matter in indoor and outdoor air was collected on a quartz fiber filter at a flow rate of 23.5 L/min. by a low volume air sampler for 7-day duration, at the terrace and living room of an apartment house in Kanagawa, Japan. Collected materials were extracted with sterilized distilled water by mild shaking. After filtration with 0.45 mum pore size filter, the extracts were subsequently mixed with a bacterium solution in a well of 24-well plate and time courses of bioluminescence intensity were measured by a luminometer. As a result, the water extracts of indoor and outdoor aerosol samples significantly reduced the bioluminescence of Vibrio fischeri and the inhibition per sampling volume increased with increasing TSP concentrations. The inhibition per unit mass of the indoor aerosols became greater than that of outdoor aerosols, when increasing in air change rate. The inhibition tended to correlate with nitrate and sulfate concentrations in the extracts. This study showed possible application of bioassay to the monitoring of indoor suspended particle contamination.