[Atmospheric and respiratory contamination by waste water aerosols]

A study was undertaken of the particle size of aerosols, emitted by a treatment plant for urban waste water, by counting the total flora, using and Andersen apparatus. Evidence of significant bacterial contamination was obtained on the perimeter of the installations. Calculations were made on the data obtained using a method to show the number of viable particles deposited at different levels within the pulmonary tree. During the working day approximately 10(4) viable particles, representing 1.5 x 10(6) organisms, products of the common flora of activated sludge were inhaled. Only a small fraction enters the pulmonary acini; the greater part are swallowed or excreted via the nose or on coughing.