RESUMO
The dilution rates of indicators Enterococcus faecalis and E. coli were studied from the St. John's River estuary in Grenada, West Indies. Health risk zones were established based on the levels of bacteriological pollution. In accordance with the World Health Organization (WHO) health risk guidelines, risks were in the range of <1% gastrointestinal (GI); <0.3% acute febrile respiratory illness (AFRI) to a 1%-5% GI; and 0.9%-1.9% AFRI within 100 m from the St. John's River outflow site in St. George's Bay. These values were the result of river water dilution, where the most probable number (MPN) levels for both indicator organisms from the river were equivalent to that of raw sewage with an AFRI health risk of >3.9% and a GI risk of >10%. The distance intervals farther than 100 m showed fluctuating values and corresponding health risks. E. faecalis and E. coli strains isolated were resistant to 35.7% and 42.9% of the antibiotics tested, respectively.