Comparative survival of faecal and human contaminants and use of Staphylococcus aureus as an effective indicator of human pollution

Comparative survival tests of faecal coliforms (FC), faecal streptococci (F S), Salmonella spp. and Staphylococcus aureus grown in sea (35 parts per th ousand, of salinity) and brackish water (27 parts per thousand, of salinity ) were performed in the dark at room temperature (22 +/- 2 degrees C), In s eawater T90 was: S. aureas > FS > Salmonella spp, > FC, Survival in brackis h water generally appeared to be higher than in seawater; in particular thi s increased from 48 to 72 h, from 88 to 104 h and from 56 to 80 h, respecti vely for FC, FS and Salmonella spp, A lower salinity had no effect on the s urvival rates of S, aureus whose T90 remained stable (96 h), FC proved to b e the most sensitive bacteria to salinity and S. arn eus the most adaptable one. There should be caution in interpreting these data; however it seems that S, Rm ells could be an effective indicator of human pollution and that the microbiological parameters used for the control of seawater could be r econsidered. (C) 2000 Elsevier Science Ltd. All rights reserved.