Abstract
Parmotrema austrosinense (Zahlbr.) Hale lichens were
collected from the Pretoria central business district (CBD),
as well as three sites to the east of Pretoria; the National
Botanical Gardens, the CSIR campus and the suburb of
Lynnwood, with the aim of utilising these lichens as biomonitors
of air quality to determine the effects of the phasing
out of leaded petrol and the simultaneous introduction
of manganese anti-knock additives to fuel in South Africa.
In addition to lichens, roadside dust and soil samples were
collected from the CBD and CSIR campus, and all samples
were analysed by flame atomic absorption spectrometry after
acid digestion. There was no significant difference (95 %
confidence) between the Mn content of lichens from all
sampling sites (overall average of 97.1 ± 39.1 μg.g-1, n=
28), which was most likely due to an even suspension of
Mn-containing particles arising from soil dust. Additional
contributions to Mn loading as a result of vehicle emissions
were currently not evident. For all non-CBD sites, higher
Pb levels were found in lichens which were nearer to busy
roads, suggesting an historical impact by vehicular emissions
of Pb arising from leaded petrol usage. The Pb concentrations
in lichens found in the CBD (average of 181.1
± 98.0 μg.g-1, n=10) were significantly higher (95 % confidence
limits) than those of lichens growing outside of the
CBD area (average of 41.5 ± 36.4 μg.g-1, n=18), and the Pb
levels were higher than those of Mn, which was contrary
to that found in sites outside the CBD.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:tut/oai:encore.tut.ac.za:d1001756 |
| Date | 25 August 2008 |
| Creators | Forbes, PBC, Thanjekwayo, M, Okokwo, JO, Sekhula, M, Zvinowanda, C |
| Publisher | Fresenius Environmental Bulletin |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | |
| Rights | Fresenius Environmental Bulletin |
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