Bacteriological and chemical studies in Baradero River (Argentina): Sanitary water quality and
fish safety. As a result of an agreement subscribed by the Municipal Government of Baradero and the
INIDEP, the sanitary quality of the Baradero River waters was studied and fish safety assessed. This
paper deals with the results of five field surveys carried out between 1993 and 1997. Organochlorine
and organophosphorate pesticide residues, as well as traces of heavy metals were analyzed in 49 fish
specimens and aerobic heterotrophic bacteria (AHB), total coliform bacteria (TC) and fecal coliform
bacteria (FC) were counted out in 7 sampling stations placed on the coast and the riverbed. Alpha
Hexachlorohexane, gamma Hexachlorohexane, beta Hexachlorohexane, Aldrin, Heptachlor epoxide,
pp'DDE and Dieldrin were detected in fish tissues. The values of AHB found in different stations were
not statistically different. The FC density on the coast was significantly greater than that found in the
riverbed. Enterobacter cloacae, Morganella morganii, Proteus mirabilis, Escherichia coli, Aeromonas
hydrophila and Non-O1 Vibrio cholerae were identified. It is concluded that the current levels of heavy
metals and pesticide residues in fish are not dangerous for the average consumer; nevertheless, further
research is needed to assess the risk for groups with higher consumption rates, such as sport and subsistence fishers. On the other hand, there is microbiological pollution in the river owed to both, industrial wastewater and sewage discharges. The recorded bacterial stocks, pathogenic or potentially pathogenic, are susceptible to cause illnesses.
Key words: Pollution, pesticide residues, heavy metals, coliform bacteria, sanitary quality, Baradero river.