Abstract

Chigozie John Onyinye Anarado, Charity Ebere Anarado^*, Francis Chisom Nwajide, Augustine Obiora, Vinna Dan Chukwuma and Ijeoma Lilian Anarado

DOI : http://dx.doi.org/10.13005/ojc/360317

Fertilizer application has gained much attention because not only has it been increasing crop yield (improving the economy of the farmers), but also been increasing/decreasing heavy metals uptake by many plants. In this study, four non-edible African plants- Euphorbia heterophylla, Axonopus compressus, Emilia coccinea and Scoparia dulcis were used to examine the effect of fertilizer (organic manure and Nitrogen Phosphorus Potassium (NPK) fertilizer) application on uptake of Pb, Cd, Hg and As by the plants. The seedlings of the plants were collected, planted and inoculated with 0.1M solutions of the salts, buffer 7, Organic manure and NPK fertilizers. Plant parts were harvested after 14 weeks of inoculation, washed, air-dried, ashed, digested and analyzed for the presence of the four metal ions. The results showed increase in pH decreased the absorption of Pb, Cd, Hg, As by A. compressus and S. dulcis. Organic manure application at pH of 6.3 increased the uptake of; Pb by A. compressus and E. coccinea. At pH of 7, organic manure application increased the uptake of; Pb by E. heterophylla and A. compressus. Application of NPK fertilizer at pH of 6.3 increased the uptake of; Pb by A. compressus and S. dulcis. At pH of 7, NPK fertilizer application increased the absorption of; Pb and Cd by all the plants, Hg by A. compressus, As by E. coccinea and S. dulcis. Most of Pb uptake were found in the roots showing that the plants can be used to phytostabilize the metal ion. Though As was phytotoxic, it was the highest absorbed among the four and E. coccinea could be used as an arsenic hyperaccumulator.

Phytoremediation, Fertilizers, Euphorbia heterophylla; Axonopus compressus

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