ASSESSMENT OF PHYTOTOXIC EFFECTS OF INDUSTRIAL WASTEWATER ON OKRA (Abelmoschus esculentus L.) AND AFRICA SPINACH (Amaranthus hybridus L.)

Abstract

In Nigeria, most of the industrial units discharge their toxic liquid effluent to the nearby water bodies and to the environment. This study was conducted to demonstrate the effects of brewery industrial wastewater on the morphology and histopathology of Okra (Abelmoschus esculentus L.) and African spinach (Amaranthus hybridus L.). The study was carried out in a screen house. Three (3) different volumes of brewery wastewater: 50 ml, 100 ml, 150 ml and a control (0.00 ml) were applied to five (5) kg of dry loamy soil in perforated bowls under a completely randomized design (CRD). The parameters measured were plant height (cm), number of leaves, leaf area, stem girth, fresh weight and dry weight. The measurement was done with the use of measuring tape and the vascular tissue was dissected into thin section with the use of razor blade. During this study, it was observed that brewery wastewater induced detrimental effects on the plant tissue, morphology (plant height, leaf area, stem girth, number of leaf), chlorophyll contents, wet and dry weight of the plants. Physicochemical analysis of the soil showed that, brewery wastewater increases the soil pH, nitrogen, potassium and soil organic carbon. The cross section analysis of the stems revealed a slight pathological damage in xylem and phloem and death of parenchyma of the pith cells in A. esculentus and A. hybridus grown at low concentration (50 ml) while, the xylem and phloem appeared faintly in the vascular matrix of the plants at high concentration (150 ml). Three heavy metals were detected from the wastewater in which Nickel had the highest concentration of 3.51 ppm followed by Iron with concentration of 2.00 ppm and Chromium had the least concentration of 0.42 ppm. The study showed that Okra is more tolerant to brewery wastewater than African spinach due to its ability to hold more water and consistence growth at high concentration of industrial wastewater. However, the ability of these plants to tolerate such level of pollution suggests it may have a good bioremediation potential.