AWWA PATH56559

In spite of considerable expenditure by water companies on new sewage treatment works, sewer infrastructure and better sited outfalls, the microbiological quality of bathing waters is still a major cause of concern among health scientists and the general public. Salmonella is one of the principal pathogenic waterborne bacteria causing gastrointestinal symptoms that can be severe to humans. Such symptoms have been described in individuals using sewage contaminated recreational waters. It is generally assumed that pathogenic microorganisms are present in recreational waters when the well established indicators of faecal pollution, e.g. total coliforms (TC), faecal coliforms (FC) and faecal streptococci (FS), are detected in elevated numbers. However, detection of pathogens has been reported in samples where indicators are isolated in minimal numbers or in their absence (Polo et al 1998, Morinigo et al 1990) and several epidemiological surveys investigating the health risk to bathers swimming in sewage polluted marine waters associate morbidity to surprisingly low numbers of indicator bacteria (Cabelli et al 1982, Kay et al 1994). The objective of this study is to assess the association between the three most common indicators of faecal pollution to Salmonella spp. This could lead to an estimation of the extent of treatment necessary (expressed in indicator counts) to achieve an acceptable microbial quality (low numbers or absence of pathogens - salmonellae) of the sewage before it is disposed into a body of water in proximity to a bathing site. Sea water samples were collected from 9 coastal stations located near Athens, Greece. They were collected, stored and transported in accordance with standard procedures. Sampling was avoided during or after heavy rainfall. The samples were analyzed for concentrations of TC, FC, FS in 100ml of water. Salmonella spp were detected in 1 liter. The membrane filtration method was used according to the guidelines of the WHO Program for Pollution Monitoring in the Mediterranean Sea (WHO/UNEP 1995). Salmonella identification was carried out by appropriate biochemical and serological tests. Includes 8 references, table.

Product Details

Edition:

Vol. - No.

Published:

09/22/2002

Number of Pages:

3

File Size:

1 file , 120 KB