Contamination Health Risks of Parasitic Helminths with Reused Wastewater for Vegetable Irrigation in Mbeya, Tanzania
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Date
2019
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Publisher
Sokoine University of Agriculture
Abstract
Reuse of wastewater for vegetable irrigation is common in developing countries due to its accessibility and being rich in fertilizing elements thus improving crops yield. Regardless of these advantages, the practice plays an important role in transmission of intestinal parasitic helminths to vegetable consumers. This study was conducted to assess farmers’ awareness, perceptions, managerial and consumption practices regarding vegetables irrigated with reused wastewater on health risks of consumers. In addition, this study assessed intestinal parasitic helminths eggs concentration and profile from samples of wastewater and vegetables irrigated with wastewater. Sociological survey data were collected from 61 purposively selected smallholder vegetable farmers using semi-structured questionnaire. A total of 56 samples of effluent water from wastewater treatment ponds (WWTP), polluted stream water (PSW) and reused wastewater irrigated vegetables were collected for parasitological examination. Parasitological examination was conducted using the floatation method adopting a modified Bailenger protocol with zinc sulphate (1.3 specific gravity). Then all Taeniid eggs positive isolates were subjected to PCR for Taenia solium detection. Differences in farmers’ awareness and perception levels were analyzed by multivariate analysis of covariance (MANCOVA). The association between demographic factors and vegetable consumption practices were analyzed using multivariate linear regression analysis model. The results indicated presence of risky practices for transmission of intestinal helminths in the study area such as consumption of raw vegetables. Education levels of the respondents found to influence consumption practices of vegetables irrigated with wastewater (P<0.05) whereby more educated individuals were not certain on safety of the water. Besides, the analysis of parasitic helminths data showed that, 88% of WWTP, 78.6% of PSW and 75% of the vegetables were contaminated with intestinal parasitic helminths eggs with mean concentration of 1.14 eggs/L, 0.667 eggs/L and 3.3 eggs/100g, respectively. Intestinal parasitic helminths found were: Ascaris sp., hookworms, Taenia sp., Trichuris sp., Strongyloides sp. and Enterobius sp., and Hymenolepsis sp. Polymerase chain reaction analysis revealed that 26.7% of samples were contaminated with T. solium eggs. It is concluded that polluted streams channeled with effluent water from Kalobe (WWTPs) is contaminated with high levels of intestinal parasitic helminths eggs than what recommended by World Health Organization for unrestricted agriculture irrigation. Furthermore, molecular analysis confirmed involvement of T. solium in some isolates of Taeniid eggs. Thus, it is recommended that, community training particularly in health risks associated with contamination of crop irrigated using recovered wastewater should be considered. More studies should be conducted on reused wastewater chemical contaminations and other microbial pathogens profiles using modern techniques such as molecular methods.
Description
This is a Master Dissertation
Keywords
Contamination health; Parasitic helminths; Vegetable irrigation; Irrigation; Wastewater