Abstract
M.Sc. (Zoology)
Tilapia sparrmanii (Smith) obtained from the Provincial Fishery in Lydenburg
was used for toxicological studies. The haematology of T. sparrmanii was
investigated after exposure to sub-lethal doses of atrazine, zinc and iron for
72 hours in a continuous flow and static system, as well as prolonged (4 weeks)
exposure in the continuous flow system. After exposure the blood of the
experimental fish were sampled. Mean values and standard errors were obtained
for several haematological parameters such as number of red and white blood
cells, haematocrit, haemoglobin, mean corpuscular volume, pH, plasma glucose-,
protein-, lipid- and lactate concentrations, as well as plasma Na+, K+, eland
Ca+. Statistically significant differences were found between the values
of haematological parameters of experimental and control fish. A tendency
towards haemoconcentration was observed when fish were exposed to the low
pollutant concentrations, while signs of haemodilution was found at higher
concentrations. The results in this study demonstrate that, after prolonged
exposure, T. sparrmanii develops a tolerance and partially recovers from the
stress condition.
The bioconcentration of atrazine in the blood of T. sparrmanii after exposure
were determined by liquid chromatography and zinc and iron by atomic absorption
spectrophotometry. During this study it was found that atrazine, zinc and iron
concentrated in the blood of T. sparrmanii after short- and prolonged exposure
to the pollutants.
The routine oxygen consumption of "!'. sparrmanii exposed to atrazine, zinc and
iron were determined in a continuous flow apparatus over 72 hours. The oxygen
consumption of the experimental fish fluctuated for the first 8-12 hours during
the acclimation period. The influence of atrazine on the routine oxygen
consumption was not so drastic as that of zinc and iron. Zinc caused a decrease
in the routine oxygen consumption of the experimental fish over 72 hours, while
iron increased the routine oxygen consumption...