Abundance and distribution of fecal indicator bacteria in recreational beach sand in the southern Baltic Sea

Density and distribution of fecal indicator bacteria in dry and wet sand and the adjacent seawater of recreational marine beach in Poland, Baltic Sea, were estimated. Numbers of total coliforms, fecal coliforms and fecal streptococci were 3-9 times higher in dry sand than in the seawater and 2-6 times higher in dry sand than in wet sand. Within a year, number of fecal bacteria inhabiting the sand and seawater showed considerable monthly changes. The highest number of the studied fecal indicator bacteria in the seawater and sand occurred in spring-summer season and the best sanitary state was noted in the winter months. There were differences in the numbers of fecal indicator bacteria between the surface and subsurface sand layer with a clear decreasing trend in the number of the studied bacteria with increasing depth.