Faecal contamination of water in the Lake Mellah and its catchment area, north-eastern Algeria

Abstract

Abstract Lake Mellah close to the Mediterranean Sea in north-eastern Algeria belongs to valuable ornithological sites with numerous, often migratory, birds. To achieve the research goal, seventeen (17) sampling points were sampled based on the urbanization of the watershed. Water samples were taken at different wadis levels (upstream and downstream of settlements), as well as at the wastewater treatment plant and in Lake Mellah based on four measurement campaigns conducted at one frequency seasonal (high water, low water) during the year (2011/2012). Biological parameters (coliform faecal bacteria, streptococci) were analysed in water of the lake and its affluents in the laboratory of the Department of Health and Population, El Taref by the most probable number (MPN) technique of the Mac Grady table taken from various points. Obtained results were processed by the use of Bourgeois ratio (coliform faecal bacteria: streptococci) to indicate the origin of faecal contamination of waters and to establish maps of the spatio-temporal evolution of this ratio by the software Surfer 9. This way we obtained information of contamination of human origin during the dry season coming from domestic waste waters. In winter the ratio showed animal prevalence of contamination coming primarily from Animal Park in El Kala.