The swash zone interstitial water (SZIW) which occupies interstices, or spaces between sand grains at the shoreline is suspected of accumulating microbes and thus of posing a health risk for beach users. In this study we examined the presence and concentrations of filamentous fungi and yeasts in SZIW and compared the results with the fungal densities found in the beach sand at three sampling locations along a Mediterranean beach (Sturla Beach, Genoa City, Italy). Unexpectedly SZIW had the highest counts of total filamentous fungi and yeasts while sand samples always displayed lower counts. The SZIW also harboured a high fungal diversity with ten genera and 74 different strains isolated from this matrix while only eight genera and 47 different strains were isolated from the beach sand samples. Overall data from this study suggest that SZIW may constitute an important reservoir of fungal micro-organisms in the beach environment.
