An assessment of public health hazard potential of waste water use in salad crop production at Umguza irrigation lots.

Abstract

Famers at Umguza litigation Lots practise unrestricted crop production using undertreated domestic and industrial wastewater. However, this presents potential public health risk to those manning the production, the vendors who sale the produce and the consumers of the produce. This research was conducted at Umguza Irrigation Lots of Umguza District, Matabeleland North Province, Zimbabwe during the period starting from 30th of October 2013 to 26th of February 2014. The thrust of the research was on the establishment of the level of public health risk of undertreated wastewater use in unrestricted crop production at UmguzaIn'igation Lots. Samples of irrigation water collected from dam, canal and overnight reservoir and vegetables_y (Lettuce (Lactucascttiva), cabbage (Brassica oleraceci) and tomato (Solarium lycopersicum) were obtained and analysed for microbial and physiochemical characteristics. Both irrigation water and vegetable samples were obtained in duplicate totalling six samples at each sampling point for the entire research. The samples were obtained before the onset of rain, season, mid rain season and approximately end of rain season. The fanners at UmguzaInigation Lots are growing salad crops which include lettuce (.Lactuca sativa), cabbage (Brassica oleracea) and tomato (,Solarium lycopersicum) using wastewater. The mean pH value for the inigation water was 8.9 and was slightly above the FAO range of 6.5-8.5 units. The EC value was averaged at 866.9|jS/cm far less than the 2000(jS/cm FAO guidelines. Pathogens (E.coli 0157, Shigella, Salmonella and S aureus) were isolated in the wastewater with a steady decrease in pathogen concentration as the rain season progressed. The same trend of pathogen concentration decrease was also observed on vegetable samples. The level of contamination by pathogen was noted to be ranging from significantly low to nil where drip irrigation system was used. Future research is recommended to determine the extent of contamination and conduct confirmatory test like Biochemical tests or Quantitative Real- Time Polymerase Chain Reaction.