J.Abah, F. I. Abdulrahaman, N. P. Ndahi, V. O. Ogugbuaja
Department of Chemistry, Benue State University, P.M.B. 102119, Makurdi, Benue State Nigeria
Department of Chemistry, University of Maiduguri, P.M.B. 1069, Maiduguri, Borno State, Nigeria
Key words: Beans, agrochemicals, heavy metals, Benue State.
The increasing usage of agrochemicals in crop cultivations has resulted in the accumulation of excess nutrient elements in the rooting and deeper soil zones. This study employed standard laboratory procedures to determine the levels of some heavy metals in seeds of beans (Phaseous vulgaris) intercropped with yams (Dioscorearotundata) cultivated under uncontrolled applications of chemical fertilizers, herbicides and pesticides in Otukpo, Ohimini and Katsina-Ala Local Government Areas of Benue State, Nigeria. The study was carried out between August and December, 2009. Levels of the heavy metals were determined using SP PyeUnicam (1900) Atomic Absorption Spectrophotometer equipped with air-acetylene burner. Results of the heavy metals concentrations of the beans seeds obtained from farmers’ fields varied between 0.023±0.001μg/g Co to 1.230±0.160μg/g Fe while records of 0.012±0.002μg/g Co to 0.788±0.230μg/g Fe were obtained in the seeds obtained from control farms.
Soil samples from the farmers’ fields recorded heavy metals contents of 0.052±0.005μg/g Ni to 3.820±0.220μg/g Pb and 0.068±0.004μg/g Co to 4.310±0.120μg/g Pb within 0-20cm and 20-40cm soil depth respectively. Analyses of the variations of the levels of the heavy metals differed significantly (P < 0.05) between sample farms and locations. The mean transfer factors of the heavy metals showed high absorption of zinc, nickel, chromium and cadmium. However, the beans contents of the metals were below the dietary toxicity limits recommended by WHO. The elevated levels of the heavy metals in beans and soil samples obtained from the farmers’ fields may be due to anthropogenically induced source. Therefore, there is the need for increasing farmers awareness and training aimed at sustainable agriculture and proper agrochemical usage.
Get the original articles in Source: Volume 3, Number 1, January 2013 – JBES