The Use of Cyperus iria Linn. and Echinochloa colona Stapf. for the Phytoextraction of Cadmium and Lead from Contaminated Soil at Abandoned Metal Scrap Dumpsite

Abstract

This study investigated Cd and Pb uptake by Cyperus iria Linnand Echinochloa colona Stapf from contaminated soils enhanced with NPK fertilizer at rate of 40, 80 and 120g. AComplete Randomized Design was adopted. The research was conducted at the Center for Ecological Studies, University of Port Harcourt.Heavy metal contaminated soil (2kg) was arranged in 4 batches 4 batches (A, B and C) alongside with uncontaminated soil (batch D). A and B were each subdivided into 3 sub-plots and amended as follows: A: (40g NPK/2kg + Cyperus iria; 80g NPK/2kg + Cyperus iria and 120g NPK/2kg + Cyperus iria);B: (40g NPK/2kg + Echinochloa colona; 80g NPK/2kg + Echinochloa colona and 120g NPK/2kg + Echinochloa colona) while C (which had polluted soil with no amendment) and D (with unpolluted without amendment) were set up as control and double control experiments. This was monitored at 60-day interval.The addition of NPK caused pH increase and decrease in chloride (3687-283) sulphate (269-92.41) and conductivity (1193-209)phytoextracted with the test plant species. Translocation factor was greater than 1 for Cd and Pb in Cyperus iria grown in 40g NPK/2kg. Translocation factor was also greater than 1 for CdinEchinochloa colonagrownin 40g NPK/2kg and 120g NPK/2kg amended soil. The test plants are suitable for remediation of Cd and Pb contaminated soil, Cyperus iria can be classified as Cd and Pb accumulator plant while Echinochloa colonacan be classified as Cd accumulating plant based on theseobservations.