Page 71 - Plant-Based Remediation Processes

Chapter 4
Remediation Mechanisms of Tropical Plants
for Lead-Contaminated Environment

Olabisi Peter Abioye, Udeme Joshua Josiah Ijah,
and Sesan Abiodun Aransiola

4.1 Introduction

Heavy metals are a unique class of toxicants since they cannot be broken down to
nontoxic forms. Concentration of these heavy metals has increased drastically,
posing problems to health and environment, since the onset of the industrial
revolution. Once the heavy metals contaminate the ecosystem, they remain a
potential threat for many years (Jabeen and Ahmad 2012). The threat of heavy
metals to human and animal health is aggravated by their long-term persistence in
the environment (Gisbert et al. 2003). For instance, Pb, one of the more persistent
metal, was estimated to have soil retention time of 150–5,000 years and was
reported to maintain high concentration for as long as 150 years after sludge
application to soil (Nanda Kumar et al. 1995).
Lead (a chemical element with symbol Pb) is a silvery-white highly malleable
metal. Among its physical properties, at normal environmental conditions this
metal is presented in the solid state and is dense, ductile, and very soft with poor
electrical conductivity when compared to most other metals. The chemical symbol
for lead (Pb) is an abbreviation of the Latin word plumbum, meaning soft metal. Pb
is rarely found in native form in nature, but it combines with other elements to form
a variety of interesting and beautiful minerals. Galena, which is the dominant Pb ore
mineral, is blue-white in color when first uncovered but tarnishes to dull gray when
exposed to air. Archeological research indicates that Pb has been used by humans
for a variety of purposes for more than 5,000 years. In fact, archeological
discoveries found glazes on prehistoric ceramics. The Egyptians used grounded

O.P. Abioye (*) • U.J.J. Ijah • S.A. Aransiola
Department of Microbiology, Federal University of Technology,
P.M.B. 65, Minna, Niger State, Nigeria
e-mail: bisyem2603@yahoo.com

D.K. Gupta (ed.), Plant-Based Remediation Processes, Soil Biology 35, 59
DOI 10.1007/978-3-642-35564-6_4, # Springer-Verlag Berlin Heidelberg 2013