[Bacterial fluctuations in the recreational waters of the Mar del Plata area]

In the period comprised between 1981 and 1983, a study was carried out in relation with the bacteriological quality of the sea water used for recreational purposes. Beaches are situated along 35 km of coast, including Mar Chiquita and Gral. Pueyrredón Departments. The principal pollution focus is the city of Mar del Plata which, like many other big cities, overturns its industrial, rainy and urban sewer liquids to the sea, with no previous treatment, in most of the cases. The effluent open sewer, situated in the north suburban district, drives into the sea the content of three maximum sewers that recollect domiciliary branches. To determine quali and quantitatively heterotrophic aerobic mesophilic, psicrophilic, marine and E. coli bacteria, water samples were taken at 0.30 m depth, behind the shoal, in each of the 17 determined stations (Figure 1), and an enumeration of colonies in agar plate was carried out in duplicate. E. coli was used as indicator of fecal contamination and served to establish the quality of the water used in bath and other recreational functions. The quantification was done by recounts in plates or membrane filter methods, in duplicate, with previous revivification. Serology of strains isolated from marine medium by polyvalent sera was done. Independently of the recount obtained, the distribution of serological groups was rather uniform along all the coast. Colony-forming units (CFU) did not exceed values of 240/100 ml, except in the beach situated at 0.5 km of the effluent, which always gave values above those accepted internationally for bathing waters or other recreational uses (Figure 2).(ABSTRACT TRUNCATED AT 250 WORDS)