Abstract

The authors investigated the impact of industrial effluents from 5 different industrial concerns in Lagos, Nigeria on Okra (Abelmoschus esculentus). During the study, it was observed that these effluents induced detrimental effects on the flowering, fruiting, stem length, leaf width and leaf length of okra. Other parameters analysed were pH, electrical conductivity, total dissolved solids, chemical oxygen demand (COD), biological oxygen demand (BOD) and oil level. Results obtained show that the main drain (MD) had the highest electrical conductivity (1961 µs, pH 10.43), as well as total dissolved solids (TDS, 977 mg/l). Effluent from toiletries had the highest concentration of oil (0.121) and the lowest pH (2.75). All effluents affected the time of flowering and fruiting of okra when compared with the control. The mean number and mean weight of fruits produced were also affected, although the extent varies from effluent to effluent. The effect was more pronounced in toiletries and plastic effluents where the mean values for fruit numbers was 3 and mean weight of 17.4 g. However, the mean weight for paint was higher than toiletries. Cross-sections of the experimental okra plants showed that the effluent affected the anatomical structures of the plant; the effect being more pronounced on okra grown on MD. The anatomy of the control grown okra was not affected. The leaves of okra grown on toiletries effluent had a less mean leaf length than those grown on the rest effluents. The same trend was recorded for the mean leaf width. The stem length of okra grown on paint effluent had the least mean value and hence most affected. The highest value for all parameters studied was recorded for the control. There was a significant difference between the means of length of leaf, stem and leaf width and those of the control, signifying the effects which industrial effluents could have on the growth and productivity of plants.

Key words: Abelmoschus, anatomy, effluent, cross-section, fruiting.