title: Sorption kinetics of Escherichia coli and Salmonella sp on two soil layers associated with a groundwater table in Yaounde, Cameroon (Central Africa).
abstract: A laboratory study has been carried out on two soil layers (H[X] and H[Y]) located above a groundwater table in Yaounde, Cameroon (Central Africa). The main purpose of this study was to assess the retention potential or sorption kinetics of Escherichia coli and Salmonella sp. on these soil layers. For both soil layers, bacterial sorption on soil particles occurred rapidly during the first 30 minutes of incubation of bacteria and soil particles in aqueous media, and increased gradually with incubation time up to 300 min. In some cases, adsorption rates fluctuated after 30 min of incubation, probably due to bacterial cell sorption to and de-sorption from soil particles. Using Freundlich isotherms, it was noted that adsorption coefficient related to adsorption capacity varied from 19 to 4026 E. coli.mg(-1) of soil, and from 506 to 847 Salmonella sp.mg(-1) of soil. For both bacterial species, the adsorption coefficient of layer H[Y] (located in close proximity of the water table) was greater than that of H[X] (located above layer H[Y]) and seemed to positively correlate with the pH values and N/P ratios, and to negatively correlate with the values of C/N and C/P ratios. The linearity coefficient related to adsorption intensity varied from 0.5841 to 1.0023 for E. coli, and from 0.7068 to 1.5236 for Salmonella sp. The physico-chemical characteristics of soil particles seemed to influence the sorption kinetics of bacteria on soil.
authors.affiliation: University of Yaounde 1, Faculty of Sciences, Laboratory of General Biology, P.O. Box 812 Yaounde, Cameroon. mnola@uycdc.uninet.cm
authors.forename: Moïse
authors.initials: M
authors.lastname: Nola
authors.forename: Thomas
authors.initials: T
authors.lastname: Njiné
authors.forename: Claude
authors.initials: C
authors.lastname: Boutin
authors.forename: Pierre
authors.initials: P
authors.lastname: Servais
authors.forename: Mohamed
authors.initials: M
authors.lastname: Messouli
authors.forename: Louise Marie Ngo
authors.initials: LM
authors.lastname: Bidjeck
authors.forename: Adolphe
authors.initials: A
authors.lastname: Monkiedje
authors.forename: Serge H Zébazé
authors.initials: SH
authors.lastname: Togouet
authors.forename: Norbert
authors.initials: N
authors.lastname: Kemka
mesh_terms: D000327:Adsorption; D002163:Cameroon; D004926:Escherichia coli / Q000737:chemistry*; D007700:Kinetics; D012475:Salmonella / Q000737:chemistry*; D012987:Soil; D014881:Water Supply
chemical_list: D012987:Soil