Letshwenyo Moatlhodi Wise, Mokokwe Gobusaone
Botswana International University of Science and Technology, Faculty of Engineering and Technology, Private Bag 16, Palapye, Botswana.
Department of Civil and Environmental Engineering, Private Bag 16, Palapye, Botswana.
Heliyon. 2020 Oct 13;6(10):e05241. doi: 10.1016/j.heliyon.2020.e05241. eCollection 2020 Oct.
Shortage of water for agriculture has resulted in the need to explore the use of wastewater for irrigation, however this can pose a health problem to the people emanating from the produced food as a result of the accumulation of pollutants. The purpose of this research was to investigate the accumulation of some heavy metals and bacteriological indicators in the different parts of spinach vegetable irrigated with secondary wastewater effluent treated through a pilot filtration system. There was a variation of heavy metals accumulation in the roots, stem and leafy parts of the vegetable. Bioaccumulation factors of some metals were greater than 1 in the roots and stems but not in the leaves. Three heavy metals being copper, iron and zinc revealed high translocation factors in the stems than leaves; whereas arsenic, chromium, nickel, manganese and lead had high translocation factors in the leaves than stems. Health index coefficients in the stem during the first, second and third months were 2.33, 0.18 and 3.57 respectively, and corresponding values in the leaves were 0.68, 0.09 and 6.75 if consumed by adults. The health index values greater than 1 in children were 2.68 in the stem during the first month and then 4.1 and 7.76 in the stem and leaves during the third month for spinach consumed by children. There was no bacteriological indicators detected in the aboveground parts of the vegetable. To conclude, irrigation of vegetables should be practiced using secondary treated wastewater and monitoring over time intervals in order to safe guard human health.
农业用水短缺导致有必要探索将废水用于灌溉，然而，由于污染物的积累，这可能会给食用由此生产的食物的人们带来健康问题。本研究的目的是调查用通过中试过滤系统处理的二级废水灌溉的菠菜蔬菜不同部位中一些重金属和细菌学指标的积累情况。蔬菜的根、茎和叶部分的重金属积累存在差异。一些金属在根和茎中的生物积累因子大于1，但在叶中则不然。铜、铁和锌这三种重金属在茎中的转运因子高于叶；而砷、铬、镍、锰和铅在叶中的转运因子高于茎。如果成年人食用，在第一、第二和第三个月茎中的健康指数系数分别为2.33、0.18和3.57，叶中的相应值为0.68、0.09和6.75。儿童食用的菠菜在第一个月茎中的健康指数值大于1为2.68，在第三个月茎和叶中的健康指数值分别为4.1和7.76。在蔬菜的地上部分未检测到细菌学指标。总之，蔬菜灌溉应使用二级处理后的废水，并进行定期监测，以保障人类健康。
