With parts of SA in a malaria endemic area, a preventative way of fighting
malaria is with the use of pesticides such as 1,1,1–Trichloro–2,2–bis(pclorophenyl)
ethane, also known as DDT. DDT is listed under the persistent organic
pollutants (POPs) and considered an endocrine disruptive compound (EDC) under
the Stockholm Convention. SA registered an exemption to use DDT as means to
fight malaria. DDT and its isomers are, however, known EDCs. Combined with their
ability to persist in the environment while not being target specific motivates further
studies into possible detrimental effects.
The present study aimed to establish if ED was present by comparing the
male reproductive organs from snails from an area currently sprayed with DDT (for
malaria control) to an area not sprayed with DDT in the Limpopo Province. A possible
endpoint (the penis sheath/preputium length ratio or PSPLR) was identified for the
freshwater snail Bulinus tropicus.
B. tropicus and sediment samples were collected from DDT–sprayed and nonsprayed
areas located close together. The snails were dissected and various
morphometric parameters measured. Sediments from the sites where the snails were
collected were analysed for DDT using GC–MS.
Statistical analysis showed significant differences in PSPLR (and therefore
possible ED) between snails from the two areas. The difference in PSPLR values
was mainly due to a relatively shorter preputium for the snails from the DDT–sprayed
area. Even though the sediment samples showed that DDT was present in most of
the DDT–sprayed sites and not in the non–DDT sprayed sites, causality of the
possible ED could not be established from this field study. This study indicated the
possibility of using the PSPLR as endpoint for ED. Recommendations are made for
further development of the PSPLR and B. tropicus as biological indicators for
endocrine disruption, but causality must first be established. / Thesis (M.Sc (Environmental Science))--North-West University, Potchefstroom Campus, 2011.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nwu/oai:dspace.nwu.ac.za:10394/4510 |
| Date | January 2010 |
| Creators | Viljoen, Ignatius Michael |
| Publisher | North-West University |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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