Metals such as lead, arsenic, cadmium, copper, zinc,
nickel, and mercury are continuously being added to our
soils through various agricultural activities such as
agrochemicals usage and long-term application of urban
sewage sludge in agricultural soils, industrial activities
such as waste disposal, waste incineration and vehicle
exhausts, as well as from anthropogenic sources. All
these sources cause accumulation of metals and metalloids
in our agricultural soils and pose threat to food
safety issues and potential health risks due to soil-toplant
transfer of metals. Co-existence and persistence of
heavy metals in soils as multiple contaminants and
human exposure to them through ingestion of heavy
metal contaminated food or uptake of contaminated
drinking water can lead to their accumulation in
humans, plants and animals. They can also cause a
considerable detrimental effect on soil ecosystems,
environment and human health due to their mobilities
and solubilities which determine their speciation [1]. In
some cases, the soil may be contaminated to such an
extent that it may be classified as a hazardous waste [2]
Soil contamination with heavy metal mixtures is
receiving increasing attention from the public as well
as governmental bodies, particularly in developing
countries [3]. The remediation of such soils is important
because these usually cover large areas that are rendered
unsuitable for agricultural and other human use.