Contamination of Lettuce Plants Irrigated with Waste Water in Yaounde, Cameroon

Aims: To evaluate the effects of various treatment combinations of water contaminated with faecal sludge on the growth and microbiological characteristics of lettuce (Lactuca sativa L.) cultivated around the river Avo'o discharged zone.

Study Design: We used randomized plots in which young lettuce plants obtained from a nursery were planted in four sites (S0, S1, S2 and S3) situated 3000, 810, 100 and 350 m from the raw discharge area along river Avo'o.

Place and Duration: Field studies were carried out in Nomayos (Yaounde) during the 2009-2010 growing seasons while laboratory analysis were effected at the waste water research unit of the Department of Plant Biology at the University of Yaounde I.

Methodology: Faecal streptococci, faecal coliforms and parasitic characteristics were determined in raw discharged sludge from river Avo’o water samples collected at three different points (P1, P2, P3) and in lettuce using standard protocols. Growth parameters of the lettuce plants were also evaluated.

Results: Faecal sludge, water from river Avo'o and L. sativa showed high levels of bacteriological and parasitological pollutants. The results also revealed high concentrations of faecal coliforms and faecal streptococci (6092 and 3390 CFU/100 ml respectively), and helminth eggs (> 273 eggs / L) in water. Treatment 3 (S3) showed the largest number of leaves