Heavy Metal Levels in Paddy Soils and Rice (Oryza Sativa (L)) Exposed to Agrochemicals at Ikwo, South-East Nigeria

The heavy metal levels of rice grains produced on soils and water contaminated with agrochemicals was studied, in 2013, at Ebonyi State Rice Project, Ikwo southeastern Nigeria. The heavy metals studied were Mercury (Hg), Copper (Cu), Arsenic (As), Lead (Pb), Chromium (Cr), Fe (Iron) Cadmium (Cd), Zinc (Zn), Manganese (Mn), and Nickel (Ni). Soil and water samples and Rice grains of different varieties were collected from paddy fields of the various locations of the project and analyzed for their levels of heavy metals contamination. The results indicated that the levels of the heavy metals in the soils and water were all above the permissible levels for agricultural soils and water. The results further showed that the levels of Cadmium, Chromium, Copper Lead, Zinc, Arsenic, Nickel, Manganese and Iron in polished rice were generally within the acceptable levels for human food. However, the concentration of Hg found in the polished grains of Landrace, FARO44, FARO52 and Fadama rice varieties, were higher than the World Health Organization maximum permissible concentration of mercury in polished rice for human consumption, suggesting the significance of establishing regulation measures for application of agrochemicals in the wetlands of Ikwo.