Persistence of Escherichia coli introduced into streambed sediments with goose, deer and bovine animal waste.

AIMS

The focus of this work was to compare the survival of Escherichia coli introduced into streambed sediments from goose, deer and bovine faeces vs indigenous E. coli.

METHODS AND RESULTS

The survival experiments were conducted in flow-through chambers for 32days using two sediments (mineral and organic) obtained from a first-order creek in Maryland. Bovine, goose and deer faeces were collected fresh and diluted or enriched so that added E. coli and indigenous populations were equivalent. Escherichia coli and total coliforms were enumerated using the Colilert-18 Quanti-Tray system. Patterns of E. coli survival and inactivation rates were virtually identical for indigenous strains in both mineral and organic sediments. The addition of E. coli strains from bovine, goose or deer faeces had relatively little impact on final E. coli concentrations, with the exception of deer-borne E. coli populations in the organic sediment.

CONCLUSION

These results indicate that indigenous sediment-borne E. coli strains are generally, or more, persistent than those deposited into sediments, including wildlife.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study on the survival of E. coli originating from wildlife faeces, in sediments, as opposed to bovine faeces or laboratory-cultured strains. As wildlife are likely to be the primary source of E. coli in most non agricultural watersheds, an understanding of the persistence of these strains is important to understanding microbial water quality.