[Microbial emission, immission and changes in the germ count in the cooling water during operation of wet cooling towers. IV. Communication: microbial immission in the vicinity of wet cooling towers (author's transl)].

From the emission rates of the bacterial cooling tower emission determined in field measurements (see Comm. II) the mortality rate of enterbacteria on soil, grass and solid surfaces and the mortality rate in the atmosphere taken from literature the immission rates and the long-term effect on microbial surface flora were calculated and compared with our own measurements. The values used in the calculations include large margins for error. The atmospheric germ counts determined by experiment were no higher than the calculated values; they fluctuated in terms of concentration between 20 KBE m-3 and 200 KBE m-3 in ranges which were measured in areas with little or no anthropogenic influences. The maximum long-term surface load which occurs under these assumptions is 2.3.10(5) KBE M-2. This relatively small additional load (approx. 10(-3%) would hardly be noticeable in a number of colonies of approximately 10(10) KBE m-2 normally occurring in soil and grass samples.