Agriculture Reference
In-Depth Information
7
Biological Remediation of Hydrocarbon and
Heavy Metals Contaminated Soil
Abioye, O. Peter
Institute of Biological Sciences, University of Malaya,
Kuala Lumpur
Malaysia
1. Introduction
Contamination of soil environment by hydrocarbons (mostly petroleum hydrocarbons) is
becoming prevalent across the globe. This is probably due to heavy dependence on
petroleum as a major source of energy throughout the world, rapid industrialization,
population growth and complete disregard for the environmental health. The amount of
natural crude oil seepage was estimated to be 600,000 metric tons per year with a range of
uncertainty of 200,000 metric tons per year (Kvenvolden and Cooper (2003). Release of
hydrocarbons into the environment whether accidentally or due to human activities is a
main cause of water and soil pollution (Holliger et al., 1997). These hydrocarbon pollutants
usually caused disruptions of natural equilibrium between the living species and their
natural environment. Hydrocarbon components have been known to belong to the family of
carcinogens and neurotoxic organic pollutants (Das and chandran, 2010).
Heavy metals contaminated soil from industrial waste; electronic wastes etc. on the other
hand pose a serious threat to both man and animals in the environment if not properly
remediated to the innocuous level. Environmental pollution by heavy metals which are
released into the environment through various anthropogenic activities such as mining,
energy and fuel production, electroplating, wastewater sludge treatment and agriculture is
one of the world's major environmental problem. Heavy metals or trace metals refer to a
large group of trace elements which are both industrially and biologically important.
Initially, heavy metals are naturally present in soils as natural components but as of now,
the presence of heavy metals in the environment has accelerated due to human activities.
This is a widespread problem around the world where excessive concentration of heavy
metals such as Pb, Zn, Cr, Cu, Cd, Hg, and As can be found in soils.
Soil contamination by heavy metals is consequently the most critical environmental
problems as it poses significant impacts to the human health as well as the ecosystems. The
contaminants are able to infiltrate deep into the layer of underground waters and pollute the
groundwater as well as the surface water. Heavy metals in the soil subsequently enter the
human food web through plants and they constitute risk to the ecosystem as they tend to
bioaccumulate and can be transferred from one food chain to another. Heavy metals are
discovered in various food chains where the results are usually detrimental to micro-
organisms, plants, animals and humans alike.
