ABSTRACT

 The study of the levels of heavy metals Pb, Cd, Cu, Zn and Fe in soils and plant nutrients uptake at waste dump sites in Akwa Ibom State was carried out. Two Local Government Areas (Oron and Uyo) were selected randomly for the study. Three (3) dump sites were used in Uyo and Two (2) in Oron • Soil samples were collected at a depth of 30cm and 70cm at two weeks interval for six months. The textural class of soil was observed to be a mixture of sand, loam and clay with low sand fractions in almost all the site except for Asutan and Iquita Road dump sites in Uyo and Oron respectively. The pH results show moderate acidity in all sites ranging from 5.5 - 6.0. The Total Organic Carbon (TOC) levels were higher at depths of 30cm than 70cm in all sites. The Cation Exchange Capacity ranged between 21.30 - 26.20 Cmol/kg in 30cm depth and 20.84- 26.40 Cmol/kg in 70cm depth across the dump sites. Heavy metals concentration was more at the 30cm depth than the 70cm depth with mean concentrations of Pb being 17.00mg/kg at 30cm and 10.Slmg/kg at 70cm, Cd was 12.92 mg/kg at 30cm and 6.74 mg/kg at 70cm, Cu was 45.34 mg/kg at 30cm and 18.70 mg/kg at 70cm, Zn was 76.18 mg/kg at 30cm and 37.84 mg/kg at 70cm while Fe was 162.24 mg/kg at 30cm and 133.01 mg/kg at 70cm across the dump sites. The level of heavy metals concentration in the soil was above permissible limits by World Health Organization which is Pb 0.01, Cd 0.03, Cu 2.0, Zn 3.0 and Fe 0.005 Mg!1. Correlation analysis between heavy metals and soil properties was negative with Clay, Sand, pH, Na, and CEC but positive with Silt, N%, Total Organic Carbon, Organic Matter and EA. Heavy metals correlation at different soil depth showed strong positive correlation except for Asutan Street with a weak positive correlation. In plants, Telfairia occidentalis had more heavy metals concentration when compared with Talinum triangulare and Abelmoschus Esculentus except for the cadmium which Talinium triangulare had the highest concentration. Zinc had the highest mean concentration in the plant samples followed by Copper, Lead and Cadmium. T-test of heavy metals between the soil depths showed significant difference in Udoh and Asutan street and no significant difference in Old stadium road, Iquita road and Idua Assang road. T-test of heavy metal means between the soil and plant samples showed no significant difference. Analysis of the questionnaire showed that a greater percentage of respondents were of the opinion that waste affected the environment negatively. So there is great need to minimize their release by treating such metal containing waste at source before being released into the environment. Sorting of waste could go a long way to help in waste treatment. Sites designated for dumping of waste should be analyzed for suitability and most importantly, people should learn the culture of conservation and not throw away things at the slightest whim.