The aim of this survey is to assess the microbiological impact of
irrigation water on lettuces produced on two urban agricultural sites
and sold on markets; 6 and 7%, respectively, of lettuces coming from
the sites of Pikine and Patte d'Oie were Salmonella spp. positive.
Lettuces irrigated with shallow groundwater (''Ceanes'' water) were
more contaminated (8% at both Pikine and Patte d'Oie sites) compared to
those irrigated with wastewater (4% at Pikine) or well water (5% at
Patte d'Oie). As for the lettuces in marketplaces, their contamination
seems to depend on the type of treatment occurring before sale. Lettuces
previously washed in the ``Ceanes'' were more contaminated than those
rinsed with tap water at the marketplace. Salmonella spp. have been
isolated from all marketplaces. However, the rates of contamination in
markets surrounding Patte d'Oie are higher (9 and 11% at Grand Yoff and
Dalifort) than those surrounding Pikine (4 and 2% at Zinc and Sham) or
Rufisque, the control (2%). Our results confirm that the reuse of
wastewater in irrigation is an alternative to animal manure. Its risk of
microbial contamination can be significantly reduced by washing the
vegetables with tap water before they are sold. Copyright (C) 2010 John
Wiley & Sons, Ltd.