A study was conducted in two sites: one at an electricity storage facility belonging to
the Swaziland Electricity Board (SEB) and the other at a facility that belongs to its
treated pole supplier, the Thonkwane wood creosote treatment plant. The drainage
system of these sites leads to surface waters in rivers. This is a cause of concern
since creosote contains polycyclic aromatic hydrocarbons (PAHs), which are listed
as priority pollutants by the US Environmental Protection Agency. They have toxic,
mutagenic and carcinogenic effects and as a result they pose a threat to human life
and the environment. No previous studies have been done on PAHs in Swaziland.
The main objective of this study was to determine the impact of the SEB storage
facility and the creosote treatment plant by investigating the extent of PAHs in
surrounding environments (soil, sediments and surface waters).
Preliminary studies were undertaken on the storage facility and the creosote
treatment plant. No PAHs were detected from the pole storage facility; therefore the
creosote wood treatment facility was selected as the ideal site at which to conduct
the research. Soil samples were collected from depths 15 cm and 60 cm at points
around the creosote plant, including effluent discharge points. The samples were
extracted by solid-phase micro extraction (SPME) and analysed by GC/MS. The
GC/MS, incorporating a solid phase micro extraction step, provided detection limits
ranging from 0.12 μg/g to 20.08 μg/g. The pollution patterns in the study site were
assessed using cluster analysis and principal component analysis.
Most of the 16 US EPA-listed priority pollutants were detected from the creosote
wood treatment facility. PAHs such as anthracene, fluorene, naphthalene and
fluoranthene were dominant in all the sampling sites. The compounds occurred in
very high concentrations (0.64, 0.46, 0.27 and 0.26 mg/kg respectively). These
compounds are found in pure creosote as determined in the sample taken from the
Thonkwane creosote tank site. The highest concentration of PAHs was observed in
the soil samples taken next to the road site.
The concentrations of the identified PAHs were above the acceptable minimal level
allowed in soil by the US EPA and Swaziland Environment Authority (SEA). The
levels of the PAHs are also above the recommended US EPA limit in soil, which is
0.1 mg/kg. The results indicated that significant soil pollution was taking place in
some of the sampling sites.
The top layer (0, 15 cm) contained many PAHs at high levels whilst the 60 cm layer
had a lower number of PAHs which were also in low concentrations. This provided
an indication that there is no downward movement of PAHs from the surface layer to
underground layers. The potential exists for contamination of surface waters when
there is runoff from the project area. This is a cause of concern, since both the
creosote treatment plant and areas outside the facility are contaminated. Therefore,
the site has to be cleaned up, preferably by using a phytoremediation technique. / Environmental Sciences / M. Sc. (Environmental Science)
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:unisa/oai:umkn-dsp01.int.unisa.ac.za:10500/549 |
| Date | 30 June 2007 |
| Creators | Van Zuydam, Constance Sthembile |
| Contributors | Thwala, J. M., Mearns, K. F. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | 1 online resource (x, 112 leaves : ill. (some col.), maps (some col.) |
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