Qualidade microbiológica da água usada na irrigação de alface (Lactuca sativa) no vale de Infulene

Abstract

The objective of this monograph was to evaluate the microbiological quality of the water used for irrigation of lettuce in the Infulene Valley, an area located in a natural depression in the smooth and undulating plain on the western outskirts of Maputo city. For this purpose, four (4) different sources of water for irrigation were chosen. Twenty-four (24) water samples were collected from four (4) sources of water used for irrigation, two of which were pre-irrigation water sources and others already used for irrigation of lettuce. The sources used were: tap water or drinking water (before and after irrigation) and water from WWTP effluents or wastewater (before and after irrigation). The microbiological quality of the water was analyzed by the filtration technique in filter membranes. The results of this study showed growth of fecal coliforms (E. coli) in all samples (24 samples) collected from the (4) sources of irrigation water from a waste source, where the average growth rate of fecal coliforms (E. coli) for samples before irrigation was 7.08 logUF/100ml and after irrigation 7.28logUF/100ml. Regarding the source of drinking water used for irrigation, the average growth rate of fecal coliforms (E. coli) was 0.39logUF/100ml before irrigation of lettuce (P3) and 4.98logUF/100ml after irrigation of lettuce. The overall mean count of E. coli showed statistically significant differences through the analysis of variance test (ANOVA: F=4.601449; p=0.003; TuskeyHSD; α>0.005) between the groups tap water or drinking water (before and after irrigation) and water from WWTP effluents or wastewater (before and after irrigation). The results of this study suggest that the growth rate of fecal coliforms (E. coli) is higher in samples from wastewater sources compared to water from drinking sources.. (TRADUÇÃO NOSSA)