Poisonous heavy metals in maize grown on a waste dump site in Ibadan

Overview

In as much as some metals are necessary for the good growth of plants, some others are very poisonous. The poisonous metals are usually the non-important ions in ecological systems. This study has shown that it is possible for edible monocotyledonous plants, grown on polluted soil, to take up some of the poisonous pollutants while assuming that such will be beneficial to their growth. However, the uptake and bioaccumulation of these toxic heavy metals have a great effect on the other members of the food web as they move up the food ladder.

Summary

Our findings shows that the uptake of toxic heavy metals do occur when polluted soils are used for agricultural purpose and such uptake, which usually further lead to bio-accumulation/bio-concentration, is not without consequences to the food chain/web.

Author Comments

Dr Afolayan A, PhD
Dr Afolayan A, PhD
National Center for Genetic Resources and Biotechnology (NACGRAB)
Dr
Ecology and Environmental Biology
Ibadan, oyo | Nigeria
Writing this article was a great pleasure as it has co-authors with whom I have had long standing collaborations.Dr Afolayan A, PhD

Resources

Lead, Cadmium and Iron Concentrations in Zea Mays Grown Within the Vicinity of Ori-Ile Battery Waste Dumpsite, Olodo, Ibadan, Nigeria

American Journal of Bioscience and Bioengineering

Adedotun Onoyinka Afolayan, Amusat Titilayo Hassan. Lead, Cadmium and Iron Concentrations in Zea Mays Grown Within the Vicinity of Ori-Ile Battery Waste Dumpsite, Olodo, Ibadan, Nigeria. American Journal of Bioscience and Bioengineering. Vol. 5, No. 5, 2017, pp. 92-103. doi: 10.11648/j.bio.20170505.

Agricultural produce resulting from the cultivation of polluted soil can result in undue exposure and health hazards for its consumers at different level along the food chain. Available literature has shown that maize absorbs and accumulates toxic heavy metals from polluted soils. This study was designed to determine the concentration of lead (Pb), cadmium (Cd) and iron (Fe) within the leaf, stem, grains and root of maize grown on Ori-Ile battery waste dumpsite, Olodo, Ibadan Nigeria. Soil samples were collected every two months (March 2008 to July 2009) from the waste dumpsite and along the direction of the garden at 5m interval from the edge of the waste dump site. To determine the levels of uptake and accumulation of Pb, Cd, and Fe, maize was planted in a nearby house garden, situated within 25m distance away from the waste dumpsite and the root, stem, leaf and grains were harvested at maturity. All soil samples collected and the harvested maize parts were analysed for Pb, Cd, and Fe. Concentrations of Pb, Cd and Fe in soil were found to range from 3265.8±517.8 to 4351.3±1068.2; 163.96±23.2 to 258.38±123.1; 7712.90±473.8 to 8130.00±808.4 mg/kg respectively. These were significantly higher than values obtained from the reference soil (157.0±39.8, 2.2±1.2, 976.3±353.9 mg/kg respectively) and National Environmental Standard Regulation Agency (NESREA) limits (164mgPb/kg and 50mgCd/kg). Also, soil contamination factor values obtained were greater than 6 and this indicated severe contamination. Concentrations of Pb, Cd and Fe in maize-parts were significantly higher (P ≤ 0.05) than those cultivated on the reference site soil. Roots had the highest concentration of Pb (40.95±1.98 mg/L) and Cd (2.84±0.19 mg/L). In all maize-parts, bio-accumulation factor of the heavy metals was less than 1. Overall, these results have shown that the levels of metals in soil were several folds above the limits set by NESREA. Also, the range within the analysed plant parts was above the normal limit recommended for plants. High accumulation of heavy metals found in the soils of Ori-Ile battery waste dumpsite, Olodo, Ibadan bio-accumulated in maizeroots. Therefore, maize root is actively involved in phyto extraction of heavy metals from contaminated soils.
November 2017
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