impact of local geography and meteorological conditions on water quality should also be evaluated. In most cases it will be necessary to collect representative water samples to confirm the presence of faecal pollution, to establish its variability and to identify the source. Non-toxic fluorescent tracer dyes, bacteriophages (such as PDR-1) or faecal sterol biomarkers (coprostanol and 24-ethylcoprostanol) may also be helpful to identify sources of contamination.
Epidemiological studies have shown that bathers can be a significant source of pathogenic micro-organisms (Seyfried et al., 1985; Calderon et al., 1991; Cheung et al., 1991). In small bathing areas with a lot of bathers and a low rate of water turnover, the person to person disease transmission has to be considered, even if there is no source of faecal pollution from the outside. The assessment may therefore need to consider measures to control microbiological water pollution by bathers in the area. This is especially important in shallow, enclosed areas used by young children where water circulation and flushing rates are low. Intensive studies to locate sources of pollution and to propose remedial actions have been undertaken successfully (Wyer et al., 1994; Tsanis et al., 1995; Marsalek et al., 1996). A specially designed form can assist in the process of comprehensive sanitary inspection (Box 8.1).
Box 8.1 Sanitary inspection form
Area name and code number: ____________________________ Location: ____________________________________________
Type of water: Fresh
Responsible authority: __________________________________ Address: ____________________________________________ Tel. ________ Fax. ________ E-mail ______________________
Laboratory of analysis: Name: ______________________________________________ Distance (km) _____ Sample transport time (h) _______________ Person responsible for samples during transport: ______________
What land or human activity surrounds the bathing area? (check all that apply)
_ _ _ _ _ _ _ _ _
Is the area surrounding the bathing area urban? ____
Additional details (historical information, reason for assessment, other contacts, etc.): Size of bathing area: Area (m2) ___ Length (m) ___ Mean width (m) ___ Is there a beach? ___ Average area (m2) ___ Length (m) ___ Width (m) at high tide ___ Width (m) at low tide ___ Prevailing onshore winds: Direction ____ Typical speed (km/h) ____ Prevailing water currents: Direction ____ Typical speed (m s-1) ____ Shoreline configuration ____ Presence of sandbars ____