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Assessment of cadium (Cd) and lead (Pb) contamination in the soils of pre-school facilities in the City of Cape Town
Author(s)
Nkoe, Nozi 'Mabafokeng
Date Issued
2009
Type
Thesis
Publisher
Cape Peninsula University of Technology
Abstract
In the last two centuries, the natural state of the environment has changed
significantly due to anthropogenic activities. With an estimated half-life of 15 -
1100 years for cadmium in soils, the metal remains a threat to the ecosystem. In
general, most soils contain <1 mg/kg, except those contaminated from discrete
sources or developed on parent materials with very high cadmium contents.
Anthropogenic lead in soil has several well recognized major sources, namely,
lead based paint, mining and smelting activities, manures, sewage sludge usage
in agriculture and contamination from vehicle exhausts. Since lead is a heavy
metal, over time it will settle down and build up in soil. The main aim of this study
was to determine the degree of cadmium and lead contamination of soil, in and
around selected pre-school facilities in the City of Cape Town (CCT). A number
of pre-school facilities, particularly those nearby heavy traffic, were selected in
the CeT. Natural soil and sand pit soil samples were collected and analysed for
cadmium and lead. Low soil moisture is normally associated with high pH, as
found in the present study. High pH values are in turn associated with low toxicity
of metal contaminants. Most urban populations rely heavily on motor vehicles
and vehicle-related pollution has been an increasing concern in recent years
(before 2006). Air pollution in the CCT is trapped by inversion layers. In this
study it has been found that cadmium is not a significant contaminant in the soils
of pre-school facilities in the CCT. The Cape Town administration area was
found to be the most contaminated with this metal. This study showed that the
Cape Town administration area also had the highest lead concentrations in pre-school soils in the CCT. This can be attributed to the higher density of industry
and traffic activities (study conducted pre-2006) in this area. There is a need for
further research to determine the relationship between soil metal concentrations
and blood metal levels, especially in children.
significantly due to anthropogenic activities. With an estimated half-life of 15 -
1100 years for cadmium in soils, the metal remains a threat to the ecosystem. In
general, most soils contain <1 mg/kg, except those contaminated from discrete
sources or developed on parent materials with very high cadmium contents.
Anthropogenic lead in soil has several well recognized major sources, namely,
lead based paint, mining and smelting activities, manures, sewage sludge usage
in agriculture and contamination from vehicle exhausts. Since lead is a heavy
metal, over time it will settle down and build up in soil. The main aim of this study
was to determine the degree of cadmium and lead contamination of soil, in and
around selected pre-school facilities in the City of Cape Town (CCT). A number
of pre-school facilities, particularly those nearby heavy traffic, were selected in
the CeT. Natural soil and sand pit soil samples were collected and analysed for
cadmium and lead. Low soil moisture is normally associated with high pH, as
found in the present study. High pH values are in turn associated with low toxicity
of metal contaminants. Most urban populations rely heavily on motor vehicles
and vehicle-related pollution has been an increasing concern in recent years
(before 2006). Air pollution in the CCT is trapped by inversion layers. In this
study it has been found that cadmium is not a significant contaminant in the soils
of pre-school facilities in the CCT. The Cape Town administration area was
found to be the most contaminated with this metal. This study showed that the
Cape Town administration area also had the highest lead concentrations in pre-school soils in the CCT. This can be attributed to the higher density of industry
and traffic activities (study conducted pre-2006) in this area. There is a need for
further research to determine the relationship between soil metal concentrations
and blood metal levels, especially in children.
Additional information
Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2009.
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