Nickel and chromium concentrations in plant tissues of accessions of Okro (Abelmoschus esculentus (L) Moench.) grown in soil contaminated with paint waste

Abstract

The proper disposal of paint waste from Paint Factories should be a concern to Environmentalists and Regulators. In this study, six accessions of Abelmoschus esculentus (okro) were grown in paint waste contaminated soil. Parameters studied were plant height, stem girth, leaf elongation rate, and chlorophyll contents. Others were tissue concentrations of Ni and Cr of plant organs. Soil chemical analysis showed that the contaminant increased pH and organic C. Ni and Cr were detected in the contaminated soils only. The paint waste contamination depressed all plant parameters studied. Differences between values obtained for control and treatment were significant for plant height, and leaf elongation rate (α = 0.05). Responses to the treatment vary among the accessions as some were depressed more than others. The plant tissue analyses show that Ni and Cr were present in all organs (root, stem, and fruit) of the plants in control and paint waste contaminated soils for all accessions, indicating the translocation of these metals from root through stem to fruits. This has implication where the plant is grown in a soil contaminated by toxic heavy metals. The differences in metal concentration of tissues as exhibited among the accessions showed three out of six to have low tissue concentration of Ni and Cr consistently