Research into Health Risks at Bathing Beaches in Hong Kong

STandARDS FOR water quality at bathing beaches are intended to protect the health of swimmers. Until recently no reliable data were available on the relationship between pollution levels as measured by indicator bacteria and the actual level of risk to swimmers. The standard used in Hong Kong uses running median levels of E. coli but is relatively lax, reflecting the lack of alternatives to what are, in some cases, moderately polluted beaches. A prospective epidemiological study has been undertaken to determine what the risks are to swimmers in such circumstances and hence to determine the required level of pollution control. It has been established that there are higher rates of minor ailments among swimmers than among non‐swimming control groups, and that the excess illness rates are pollution‐related for most symptom categories, except eye symptoms. The best indicators were found to be E. coli, and staphylococci. The existing limit of acceptability applied in Hong Kong corresponds to a risk of 15 skin and gastrointestinal cases per thousand swimmers, a reasonably low rate but still a significant public health problem when multiplied by the very large number of swimmers using the beaches in Hong Kong every year.